MANUFACTURING HEAT TREAT TECH

Heat Treat Radio #106: Heat Treat Legend Doug Peters

/ HEAT TREAT RADIO, MANUFACTURING HEAT TREAT TECH

“Don’t lose sight of who you are . . . .” In an industry where passion to create, help, and discover can become all-consuming, Doug Peters’ drive and dedication to the heat treat industry has not compromised his care to family, employees, and the joys of life. As the founder and CEO of Peters’ Heat Treating, this Heat Treat Legend joins Heat Treat Radio host, Doug Glenn, in a special episode.

Below, you can watch the video, listen to the podcast by clicking on the audio play button, or read an edited transcript.

HTT · Heat Treat Radio #106: Heat Treat Legend Doug Peters

The following transcript has been edited for your reading enjoyment.

Meet Doug Peters (01:05)

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Doug Glenn:  Doug, it’s really good to talk with you. We’ve known each other for many, many years, but it’s really nice to get a chance to sit down with you here on Heat Treat Radio’s Heat Treat Legend — it’s an appropriate title for you. I’m really glad you took the time to talk to us. Welcome to the episode.

Doug Peters:  Thanks, I appreciate it.

Doug Glenn:  The first thing we do in these episodes, Doug, is just kind of give people a sense of you, the person, before heat treat. How did you get into the industry and a little bit of the history of your experience? Why don’t you start with where you are located, as well?

Doug Peters:  We’re located in Meadville and McKean, Pennsylvania; we have two plants. The total square footage in the plants is probably roughly 70,000 square feet.

My history goes clear back to my farm days. Our family farm, which has been in our family since 1885, opened a retail milk store in 1963. My mother had no babysitter, so I had to go to work with her. During that time, I was taught how to prepare a storefront, and by the time I was 12, she had me cashing out the cash register, and reconciling all receipts at the end of the day. When “Mrs. Brown,” who was elderly, pulled up out front, you went out and met her at the car and got her bottles for her, and helped her in and out of the store. A good amount of my business acumen, believe it or not, came from my mother and that experience.

Doug Peters, a true Heat Treat Legend
Source: Peters’ Heat Treating

I graduated from Penn State University with a degree in business but, enroute, tried to be a pharmacist, so I ended up with 40 credits in the sciences. I went into the insurance business because I felt as though I needed some toughening up, people-wise. I ended up being an insurance agent for three years and had one question that I always asked customers and that was: “If I’m a genie and I can grant you one wish, what would it be?” And every tool shop I called on said, “We need a good heat treater.”

I had worked for my wife’s father in a tool and die shop, in the summers, as a saw boy, etc., so I sort of knew what heat treating was. Well, I went and discussed it with my wife’s father, and he gave me the name of a gentleman who had just retired from Talon after 32 years in their heat treating department. I called him on the phone, I paid him under the table, and he taught me the trade. Without him, I wouldn’t be sitting here today.

Likewise, my father-in-law bought us a building and gave it to me one-year rent-free, and my father, who was a railroad engineer, showed up every day after a full shift, and helped me fix the old broken-down equipment that I had bought to start the business.

Then there was Jackie, sitting behind the scenes. She did all the books. She was a full-time schoolteacher. I went three years, to the day, without a paycheck. My first paycheck was $100.

That’s how I got started.

Doug Glenn:  What year did you actually start the heat treat?

Doug Peters:  1979, October of 1979.

Doug Glenn:  October of ’79 you started the heat treat. Wow. And there is great family involvement too, right? Your dad, your father-in-law, Jackie . . .

Doug Peters:  Yes. You know something? You certainly can’t accomplish anything by yourself. Without those guys and Jackie, we would not have been able to do what we did.

Doug Glenn:  That’s great stuff.

Help me with the math. How many years was that ago?

Doug Peters:  In October 2023, it would have been 44 years ago.

Major Accomplishments (04:40)

Doug Glenn:  So, in the 44 years, what are the highlights? Are there one or two, or two or three, major accomplishments that, when you look back, you say, “You know what? This was a major accomplishment or something pretty significant.”

Doug Peters:  I think probably the most satisfying thing to me are the families of the employees that we’ve had over the years. I’ve watched them get married, buy homes, have children, have grandchildren, and we’ve been very lucky to keep a very tenured staff over the years. Being involved with not only the employees but our customers within the community. Being able to contribute and help people as a result of what we do here in the heat treat — it’s really been the most satisfying thing for me.

Doug Glenn:  I don’t want to underemphasize that. I think that’s a classic Doug Peters answer too. You know, you are one of the most “people oriented” people I know, which is great. I told my wife, when we were starting Heat Treat Today: You know what I’m looking forward to, is paying people. I don’t know why I was looking forward to it, but I was. So, I appreciate that perspective.

Does anything jump to your mind as far as actual business accomplishments? Is there anything that happened over the years, like, for example, opening the McKean plant?

Doug Peters:  Yes, I suppose, if you look at those things. To me, those were just normal forces of business to better serve customers.

We started out with four little box furnaces with maximum capacity of 20 pounds. My first employee was my loyal dog. As we moved forward, I was lucky enough to work for a very innovative group of customers. We were on the cusp of tool and die morphing with the advent of computers into enabling (or demanding) us to really do more than traditionally what heat treating had been responsible to do.

For instance, one of the early things we did was we learned how to not control size, but influence size on a particular part and design to eliminate hard finish time on tooling. That was one of the things we did a lot of work in. We did a lot of work in straightening.

Early cryogenics work. I mean, back in 1980 and 1981, I bought a machine that would take gaseous CO₂ and compress it into very pithy dry ice. Then, utilizing ethyl alcohol as a catalyst, I could drive temperatures to -70/-75 degrees. Experimenting with that, we found that we could improve the stability of materials that were being manufactured in the shops, but most of all, improve part life. So, that was the advent of us getting into liquid nitrogen cryogenics, in the very early ‘80s.

From there, we graduated into vacuum furnaces. We have nine vacuum furnaces, presently. In 2006, we bought 20,000-pound nitriders that can do up to 138 inches in length. Then, of course, the specification requirements grew and grew, as we moved forward.

Doug Peters with family. Left to right: Doug Peters, Diana Wilkosz, Jackie Peters, and Andy Wilcosz, with three grandkids interspersed.
Source: Peters’ Heat Treating

At this point in time — and I’ve got to give my son-in-law, Andy, my daughter, Diana, and his staff a lot of credit — Jackie and I had a company that was ISO, and we could work the ASM2750 pyrometry specifications. When Andy and Diana came on board, they took us to Nadcap. Andy just put in a destructive testing laboratory. For instance, we just had our first AS audit, so those capabilities are now online.

And we’ve grown to nearly 80 employees. When you look at the major accomplishments over the years, a lot of the technical-credit goes to the people out on the shop floor who really put their shoulder on the wheel and pushed with us to go through the disciplines that are required to gain those things.

The Metal Treating Institute (09:18)

Doug Glenn:  I’d like you to address two other questions on accomplishments, if you don’t mind, Doug. You and I have had a long history in the Metal Treating Institute. I’d just like you to have a comment about your activity there, including the fact that you were a president. Then, also, would you be comfortable commenting on Laser Hard?

Doug Peters:  Sure!

As far as MTI, our company would not be successful without MTI — or as successful as it is. We’ll give Jackie the credit.

In 1984, I bought a fluidized bed from Wally Bamford. As we sat at dinner, after we had signed the purchase orders that evening, Wally shoved an application for MTI under my nose, and he said, “You’ve got to join this organization.” I asked him what it was about, and he told me, so Jackie and I joined. But we didn’t do anything for four years, except look at the sales reports and everything else.

Well, my wife signed us up for our very first meeting in 1989. Once we got there, I went, “Oh my goodness, have I been missing out on how to grow the company?” It was at that meeting that I met Chet Walthall and Roger Keeran, who ended up being wonderful mentors and friends of mine. I treasure those guys so much.

The other fellow that I met through that journey was Jack Ross who owned Ironbound. Jack would allow you to come into his plant and he’d share anything, as long as you were an MTI member — that was his only requirement.

Lance Miller was our executive secretary, at that point. My first involvement at MTI was getting a call from Chet Walthall congratulating me because I was on his education committee. Then, with forward planning — which is now strategic planning — I called Lance and asked if I could go to the meetings being held in Pittsburgh. I was not on the committee but my contention to him was, as a forty-something, I really thought that somebody younger should be on the committee that was planning the future in the institute. So, that’s my involvement, and it just mushroomed from there.

I was the millennial president in 1999 and 2000. I have been on numerous committees, chaired the Education Foundation’s institution with Norm Graves; Norm was the treasurer.

Well, yes, of course, my wife, Jackie, who was our president in in 2015. It was my pleasure to carry her briefcase that year and watch her. Her tenure, at the board level and through the chairs, was longer than mine. She served on numerous committees and she’s received a few awards, and she’s so deserving.

Doug Peters, Founder & CEO, Peters’ Heat Treating, Inc.

Doug Glenn:  In fact, if I may interrupt, you were one of the founders of that Educational Foundation, if I’m correct.

Doug Peters:  That is correct. And, you know, there were other people on our committee too, but to be able to see what the education foundation has grown to and how it will support the industry moving forward, I am very pleased to have been a part of that.

Doug Glenn:  And we’ve got to make another note here, since we mentioned Wally Bamford: It wasn’t long ago that Wally made a very significant contribution to that foundation.

Doug Peters:  Well, you’re doggone right.

Our initial bogey was a quarter of a million dollars. We weren’t going to take a nickel out until we got to $250,000. We pushed it over $250,000 and that’s when I stepped aside and we had different folks take chairs. Then we pushed it to $450,000, and now we’re giving scholarships. As a matter of fact, we had a recipient, here at the heat treat, to the Founders Scholarship. Then, of course, Wally, at our 90th anniversary, gave us a million dollars.

Doug Glenn:  Canadian!

Doug Peters:  Canadian, yes, yes! And I’m going to call Wally to make sure that he listens to this podcast, Doug.

Doug Glenn:  It was so typical Wally Bamford, right? He’s up front, he’s talking, and he says, “I’d like to donate a million dollars,” and everybody is oohing and aahing, and he leans in and says, “Canadian” in a deep voice, into the mic. It was classic. Wally needs a lot of credit there.

One other question, before we get off of MTI. Have any other people in your family been the president of MTI that you’d like to talk about?

Doug Peters:  Well, yes, of course, my wife, Jackie, who was our president in in 2015. It was my pleasure to carry her briefcase that year and watch her. Her tenure, at the board level and through the chairs, was longer than mine. She served on numerous committees and she’s received a few awards, and she’s so deserving.

Doug Glenn:  We share quite a bit in common, right? First off, we have the same names: Doug and Doug. We also have wonderful wives and, if you’re like me, people in MTI can tolerate you, but they really like your wife. That’s the way it works on my side.

Doug Peters:  Absolutely. Everybody says “hi” to her before they say “hi” to me.

Doug Glenn:  Exactly. We both married well!

So, as far as MTI, thank you for commenting on that. I just felt that was important. That’s one of the reasons why I think both you and Jackie really are kind of heat treat legends. You’ve been very active in a lot of different things, MTI especially.

Laser Hard (14:12)

Tell us briefly about Laser Hard.

Doug Peters:  Laser Hard has been a joint family venture. Good friends of ours (and customers), the Learn family has been doing laser welding and cladding for a good number of years and are principals in Alpha Laser in North America. The patriarch, Blair Learn, gave me a call and said, “I want to show you something.” So, I went down and looked at it and, when all was said and done, we decided to partner. He knew lasers and I knew heat treating and we felt as though there was a real need.

The things that we’ve done with Laser Hard, in solving issues that cannot be solved in traditional heat treating, do not cease to amaze me on a daily basis. The type of customers that we’re attracting, including large toolmakers (Tesla, Ford) there are all kinds of people that have come and worked with us on applications that we have had an opportunity to pioneer, literally.

It’s just been a wonderful partnership. I can’t say enough good things about Phoenix Laser, Inc.; that is the formal name of our partner’s company, and the Learn and Peters connection continues to thrive.

Doug Glenn:  That’s great, that’s great. If anyone wants additional information on Laser Hard or Phoenix Laser, Inc., we can certainly get in touch with them.

I want to make sure people know a couple of names we’ve thrown out there, just for reference. Obviously, you’ve mentioned Jackie is your wife, and you’ve also mentioned Andy and Diana Wilkosz. Diana, of course, is your daughter, and Andy is now the plant manager/president.

Doug Peters:  He is the president of the company.

Doug Glenn:  Very good. A little kudos out again, back to the MTI relationship. Andy did a good bit of interning, I think, down at Texas Heat Treating, Inc. with Buster Crossley, if I remember correctly.

Doug Peters:  That is correct. He worked out at Buster’s plant for three years before he came up.

Doug Glenn:  Not that my opinion counts, but both Diana and Andy seem to be very accomplished folks; they represent Peters well in the industry.

Influential People (16:30)

You had mentioned, Doug, a couple of names that had a major influence or that were helpful to you, people that you want to maybe give some credit to. You mentioned about the guy at Talon. Is there anybody else, as you look back on your career, that has had a significant impact on you and helped you along the way?

Doug Peters:  There have been so many people, I almost feel remiss in naming only a few names, in case I forget somebody. Obviously, Mr. Weller Gregg, who was that Talon guy (who was the head of heat treating), that gave me the start.

The young Doug Peters
Source: Peters’ Heat Treating

My two dads. And my two moms. Jackie’s mom taught me one of the most valuable lessons in business that I tell people about and that I carry forward. Every Thursday, Jackie’s mom would watch our children, when they were young, so Jackie could come to the shop and do payroll. Then she started having us up for dinner after work.

I was up there one evening and she sensed that I was a little troubled with something, and she said, “You have something on your mind, today,” and I said, “Yeah, I have a few things going on at work,” and she said, “Well, might I suggest something? I have a question: Can you do anything about them, right now?” and I said, “Well, no,” and she said, “Well, I suggest that you worry about them when you can do something about them.”

It was absolutely the best piece of advice I ever got because I learned how to put some of those things on a shelf and deal with them when I could deal with them. I think it saved me a lot of grief and a lot of stress, over the years.

Obviously, Chet and Roger. They gave me the confidence to think that I was good enough to do this. Jim Balk, up at Hansen/Balk, was a real mentor, and he gave me the confidence that I was heading in the right direction, and we shared many of the same philosophies about how you take care of customers.

I’ll talk about Lance Miller who really put the love of the industry inside of me; I can’t say enough about Lance.

And then you look down through that long list of the notables in the industry: A shoutout to Roger Jones who’s going through a battle, right now, with cancer. Roger, we love you and we hope that everything comes through for you. John Hubbard, who’s a really good friend of mine and who was an industry giant with his career and his seat at Bodycote. Like I said, Jack Ross, and just the different people, Doug, that I’ve met over the years who were just phenomenal people.

MTI, right now, I believe, is in very capable hands with Tom Morrison and his staff. I feel very good to still be part of MTI.

Life Lessons (19:15)

Doug Glenn:  Any lessons that you’ve learned, like the one that your mother-in-law gave you, which I think is a valuable one: “Don’t worry about it until you can do something about it.” Is there anything else that you’ve learned, as a “senior” in the industry, that you think is worth discussing?

Yes, I did just call you a senior!

Doug Peters:  My parents stuffed a lesson right inside of me: be a finisher. Put all the tools away where you found them.

One of things from being in business that I can tell you is very valuable — when your name is on the sign, you accept all blame. I’ve never, in 44 years, ever thrown one of my employees under the bus to a customer. I accept the blame. Because, when something goes wrong in this building, it is something that I take responsibility for. You do not ever throw somebody under the bus; you go back and you work with them to perhaps correct the behavior, the execution, or something.

But that one’s been really important to me because, you know, you do not tear down a person’s dignity, as you work with them, whether it’s a customer or one of the folks that you work with inside of your building. So, that one has been very, very important to me.

Doug Glenn:  As you’ve worked, over the years, I’m sure the way you started working, back when you were a young man and as you’ve progressed up through, were there any disciplines you developed that really helped make you either a better person or a better businessman, or anything of that sort — anything that maybe even you continue, to this day, in disciplines?

Doug Peters:  Number one is being up really early in the mornings, when you have personal time. Because a lot of people complain that they don’t have personal time. They lose themselves in their vocation. My father was a big contributor to that. Dad used to go to work at 7:00 in the morning. He was a railroad engineer so he’d get up at like 4:30/4:45am. I said to him one day, “Dad, why do you do that?” And he looked at me and he grinned and he said, “Because you’re not!” The point was that that was his time.

“I think you have to make family time. I don’t care how busy you think you are; you have to be able to create that balance, and you have to force that balance to happen.”

Doug Peters, Founder & CEO, Peters’ Heat Treating

And I think you have to make family time. I don’t care how busy you think you are; you have to be able to create that balance, and you have to force that balance to happen. For instance, I was home every night by 5:30pm: I had dinner with my children, I played with them, we worked on homework, and when they were young, I’d help bathe them. And if I needed to go back to work, I would kiss Jackie and go back out the door after the kids were snugged in their beds.

Jackie, on the other hand, used to bring the kids to the shop. In the early days, I’d be working weekends, and she’d pack up a whole dinner and she’d come over and she’d bring the dog and the picnic table and be outside and we’d have a family dinner together. But I think, when we were together, we never really tried to not talk business because we always had our family first, business second, so that made that formula easy.

The only goal that we ever had for the company, Doug, was to be with our children when we wanted to be with them. When Diana graduated from college, I looked at Jackie and asked, “What’s the goal now?” and she said, “To be with our children when we want to be with them.” At that point, that’s been the only major goal that Jackie and I have ever had with Peters’ Heat Treating.

Learning Through Difficulties (22:37)

Doug Glenn:  That’s great.

Well, you’ve addressed the other question I was going to ask you and that was about work/life balance.

Jackie and Doug Peters receiving the Winslow Award
Source: Peters’ Heat Treating

As you know, 40 some years, not every day is sunshine and roses — sometimes there can be difficult times. Can you recall a difficult time and — if you’re comfortable talking about it — what was it and what did you learn from it?

Doug Peters:  Well, we’ve had two fires, one in each plant. Each fire was not a result of anything that was a delinquency on our part. But having to take each one of those buildings and sift through the rubble and to rebuild each one of them certainly was, I think, a character tester.

Losing key employees at the wrong time. All it did was reinforce why you do contingency planning, why you cross train, etc.

The one thing Jackie always said was it was wonderful being married to somebody that liked what he did for a living because I seldom came home, downtrodden. There were a lot of nights, in the early days of building the company, I’d be crawling into bed at 10:30pm when the phone would ring and 3rd shift would be calling off when we only had two guys up there, and I’d pull my pants back on and go back to work and then stay the whole next day. I did that numerous times as we built this company.

Those, somebody might say are “trials and tribulations,” but to me, it was just part of the job. It’s what I signed up to do and there’ll be no whining. You got your pants on, you went to work, and you were fortunate that you had a job to go to.

Career Highlights and Advice to the Next Generation (24:17)

Doug Glenn:  Obviously, there were some valleys there, like the fires and things of that sort. How about the highlight? If you could pick one thing that was the highlight of your career, what would it be?

Doug Peters:  There were a number of highlights: Watching the kids go through school and be successful in their respective careers, watching my wife be president of MTI in 2015 was a super, super highlight for me, and being fortunate to be asked to serve in the institute and to win the Heritage Award was something that was very special to me.

Here, in Meadville, we have what’s called the Winslow Award. It was started by Dr. Harry Winslow many, many years ago to go to the person that contributes the most to making sure that the Meadville economy is sound. I was the proud recipient of that in 2022. The list of names in that award, locally, is just amazing, too.

To not have made a bunch of enemies is something. You know, you have those instances where you’re in a difficult time — a job that’s gone bad or whatever. I’m very proud to say that, most of the time, when I see somebody that I haven’t seen in a while, I’m glad to see them and I think they’re glad to see me.

Doug Glenn:  Last question for you, then: You and I both are getting up there as being “seniors” in the industry. Is there any piece of advice you would give to younger people?

Doug Peters:  I think, first and foremost, don’t lose sight of who you are. I’ll go back to my father again. Dad looked at me one time and said, “Don’t become what your job is.” This all stemmed from him being a really beautiful woodworker. He could do woodworking that was gorgeous, and I asked him one time, “Why don’t you do this for a career?” and he said, “Well, it would be a job then!” And, in the course of that conversation, he looked at me and he said, “Don’t become what your job is. Be a great person that enjoys the job you chose.” I always tried to make sure that that’s who I was because I chose this vocation because I love to serve people, not because I loved to heat treat. It just so happened that heat treating was the vehicle that fulfilled my dream of serving people.

Doug Peters, Founder & CEO, Peters’ Heat Treating. Source: Peters’ Heat Treating

Dad was spot-on. Because, you know, when you retire, how many people do you see that are completely lost after they’ve walked out of their place of employment and they don’t know who they are? For me, that’s not been the case. I’ve been completely fulfilled. It was time. I’m happy to be on to the next stage in my life.

So, don’t become what your job is, is the first piece of advice I’m going to give these folks. Secondly, “Eat the frog.” Do the most unpleasant thing that you have to do every day, first, because your day is only going to get better. An MTI seminar that I went to gave me that piece of advice.

Last, but not least, take the three most important things you have to do tomorrow and write them down on a notebook and put them right in front of your computer at your desk at work so the next day when you walk in, there are only three things that are clouding your mind instead of list with 50 things. But if the day gets worse, turn the page, and write one down and take the other two off the list. It will help you focus and it will keep you moving forward.

Doug Glenn:  That’s really good advice.

You know, you were talking about not becoming your job, which reminded me of a picture I saw of you, years ago, sitting behind a drum set. Tell us about that, just a little bit.

Doug Peters:  I started playing the drums when I was in 8th grade. My father was a drummer, and he was a USO drummer. He was a sergeant in the Transport Corp, during World War II, in the European theater, and dad taught me how to play the drums. I did take some lessons, for a short time, but not as long as I would’ve liked to have.

Then, I had a rock band, and I’ve continued to play, over the years, and I play with artists on records. I’ve played, pretty much, my whole life, and I’ve enjoyed it.

Doug Glenn:  That’s the human side and that’s great.

Doug, thanks very much. I appreciate the time you’ve taken to visit with us.

Doug Peters:  Well, thank you, Doug. It’s always a pleasure.

About the Expert

Doug Peters with his wife, Jackie (Kuhn) Peters, founded Peters’ Heat Treating company in 1979. Over his career, Peters has served on numerous community service and industry trade association boards. He is past president of the NW Chapter National Tooling and Machining Association as well as the millennial president of the Metal Treating Institute.

Contact www.petersheattreat.com

Search Heat Treat Equipment And Service Providers On Heat Treat Buyers Guide.Com

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Exo Gas Composition Changes, Part 2: Cool Down and Use in Heat Treat Furnaces

/ ATMOSPHERE AIR FURNACES TECHNICAL CONTENT, BULK GASES & SYSTEMS TECHNICAL CONTENT, FEATURED NEWS, MANUFACTURING HEAT TREAT TECH

In Part 1, the author underscored the importance of understanding the changes in gas composition through three steps of its production: first, the production in the combustion chamber; second, the cool down of gas to bring the Exothermic gas (Exo gas) to below the ambient temperature; and third, the introduction of the gas to the heat treat furnace. Read Part 1, published in Heat Treat Today’s August 2023 Automotive Heat Treat print edition, to understand what Exo gas is and to learn about the composition of gas in the first step.

Harb Nayar
Founder and President TAT Technologies LLC Source: TAT

As the author demonstrated in Part 1, Exo gas composition changes in its chemistry for heat treatment; this first step is how the gas composition changes when it is produced in the combustion chamber. The composition of reaction products, temperature, Exothermic energy released, various ratios, and final dew point are all factors that need to be considered to protect metal parts that will be heat treated in the resulting atmosphere.

Now, we’ll turn to Steps 2 and 3.

Step 2: Composition of Exo Gas after Exiting the Reaction Chamber Being Cooled Down

The two examples that follow demonstrate how lean and rich Exo under equilibrium conditions change as they are cooled from peak equilibrium temperature in the combustion chamber down to different lower temperatures (Table B). This cool down brings the Exo down to below ambient temperatures to avoid water condensation.

Example 1: Lean Exo Gas with a 9:1 Air to CH₄ Ratio

The first column highlighted in blue shows the composition of the lean Exo gas as generated in the reaction chamber with an air to natural gas ratio of 9:1. The peak temperature as generated in the combustion chamber is 3721°F. The next four columns show how the composition changes when the lean Exo gas is slowly cooled from 3721°F to 2000°F, 1500°F, 1000°F, and 500°F under equilibrium condition. The following key changes take place as the temperature of the lean Exo is lowered from the peak temperature to 500°F:

  1. Hydrogen volume almost triples from 0.67% to 1.97%.
  2. H₂O volume decreases slightly from 19.1% to 17.5%, but still is very high at all temperatures.
  3. Oxidation-reduction potential (ORP) changes as the H₂ to H₂O ratio increases from 0.035 to 0.111. At all temperatures, it is very low.
  4. CO and the CO to CO₂ ratio drop in a big way, making lean Exo from being decarburizing at higher temperatures to being highly decarburizing at lower temperatures.
  5. The percentage of N₂ remains at 70.34 at all temperatures.
  6. There is no C (carbon, i.e., soot) or residual CH₄ at all temperatures.
  7. For all practical purposes, at an air to natural gas ratio of 9:1, the Exo gas as generated is predominantly an N₂ and H₂ (steam) atmosphere with some CO₂ and small amounts of H₂ and CO.
Table B. Air to Natural Gas at 9:1 and 7:1, cooled to various temperatures

Example 2: Rich Exo Gas with a 7:1 Air to CH₄

The column under ratio of seven is highlighted as red to show the composition of the rich Exo gas as generated in the reaction chamber with an air to CH₄ ratio of seven. The peak temperature is 3182°F — significantly lower than that for lean Exo. The next four columns show how the composition changes when the rich Exo gas is slowly cooled from 3182°F to 2000°F, 1500°F, 1000°F, and 500°F. The following key changes take place as temperature of the rich Exo is lowered from the peak temperature to 500°F:

  1. Hydrogen volume almost doubles from 5.58% at peak temperature to 9.91% at 1000°F, and then it drops to 5.70% at 500°F. The overall volume of H₂ in rich Exo is significantly higher than in lean Exo.
  2. H₂O volume decreases slightly from 17.9% to 15.1%, but it is still very high at all temperatures.
  3. Oxidation-reduction potential (ORP) changes as the H₂ to H₂O ratio increases from 0.312 at peak temperature to 0.737 at 1000°F before decreasing to 0.377 at 500°F. Overall, ORP in rich Exo is significantly higher than that in lean Exo.
  4. CO and the CO to CO₂ ratio drop in a big way, making it mildly decarburizing to more decarburizing
  5. The percentage of N₂ remains at 65– 67%, which is lower than lean Exo.
  6. There is no C (carbon, i.e., soot) at any temperature. However, there is residual CH₄ at 1000°F and lower. This increases rapidly when cooled slowly below 1000°F.
  7. For all practical purposes, the rich Exo gas (at air to natural gas ratio of 7:1) generated is still predominantly a H₂
    and H₂O (steam) atmosphere, but with more H₂; hence, it has somewhat higher oxidation-reduction potential (ORP) than lean Exo and a bit higher CO to CO₂ ratio (less decarburizing than lean Exo).

In summary, rich Exo as generated in the combustion chamber differs from lean Exo as follows:

  1. It has a little less N₂ % as compared to lean Exo.
  2. It has significantly more H₂ , but a little less H₂O than lean Exo. As such, it has a significantly higher H₂ to H₂O ratio (ORP).
  3. It is decarburizing, but less than lean Exo.
  4. It has residual CH₄ at temperatures below 1000°F. Therefore, it must be cooled very quickly to suppress the reaction of developing too much residual CH₄.

Discussion

Let us take the example of rich Exo (an air to natural gas of 7:1) exiting from the reaction chamber in Table B (see column highlighted in red). The total volume is 853.3 SCFH and has H₂O at 152.4 SCFH (17.9% by volume). This is equivalent to dew point of 137°F. Its H₂ content is 47.6 SCFH (5.58% by volume). And the H₂ to H₂O ratio is 0.312.

If this were quenched to close to ambient temperature “instantly,” this composition would be “frozen,” except most of the H₂O vapor will become water. Let us assume the Exo gas was instantly quenched to 80°F (3.6% by volume after condensed water is removed). Rough calculation shows that the final total volume of H₂O vapor has to be reduced from 152.4 SCFH to about 26.0 SCFH in order to meet the 80°F dew point goal. This means 152.4 – 26.0 = 126.4 SCFH of H₂O vapor got condensed to water.

Now the total volume of Exo gas after cooling down to 80°F= 853.35 – 126.4 = 726.95 SCFH, or almost 15% reduction in volume of Exo gas as compared to what was generated in the reaction chamber.

Of course, the composition of Exo gas will not be the same as calculated above. The exact composition after being cooled down depends upon the following:

a. Cooling rate of the reaction products from the peak temperature in the reaction chamber to some intermediate temperature, typically around 1500°F.
b. Cooling rate of the gas from the intermediate temperature to the final (lowest) temperature via water heat exchangers — typically 10–20°F below ambient temperature unless a chiller or dryer is installed on the system.

Depending upon the overall design of the generator, especially how Exo gas coming out of the combustion chamber is cooled and maintained during the period of its use, the expected Exo gas composition should be in the range of the light red columns in Table B — where temperatures are between 1500°F to 1000°F — however:

  1. Total volume closer to 727 SCFH (since a major portion of H₂O was condensed out)
  2. N₂ between 74–77%
  3. Dew point between 80–90°F
  4. CH₄. between 0.1–0.5%
  5. H₂ percentage between 7–9%

Step 3: Composition of Exo Gas after Being Introduced into the Heat Treat Furnace

The cooled down Exo gas will once again change its composition depending upon the temperature inside the furnace where parts are being thermally processed.

As an illustration, let us assume the following composition of the rich Exo gas (with a 7:1 air to natural gas ratio) at ambient temperature just before it enters the furnace:

  • Total volume: 727 SCFH
  • H₂: 8% (58.16 SCFH)
  • Dew Point 86°F or 4.37% (31.77 SCFH)
  • CO: 6% (43.62 SCFH)
  • CO₂: 6% (43.62 SCFH)
  • CH₄ : 0.4% (2.91 SFH)
  • Balance N₂ (%)
  • 75.23% (546.92 SCFH)

Table C shows how the composition changes once it reaches the high heat section of the furnace where parts are being thermally treated. The column highlighted blue shows the composition of Exo gas as it is about to enter while it is still at the ambient temperature. The next three columns show the composition of the Exo gas in the high heat section of furnaces operating at three different temperatures depending upon the heat treat application — 1100°F like annealing of copper, 1500°F like annealing of steel tubes, and 2000°F like copper brazing of steel products. The H₂ to H₂O ratio decreases as temperature increases.

Other general comments on Exo generators:

  1. Generally, they are horizontal.
  2. Size ranges from 1,000 to 60,000 SCFH.
  3. Rich Exo generators use Ni as a catalyst in the reaction chamber. Lean Exo does not.
  4. Lean Exo generators typically operate at a 9:1 air to natural gas ratio. There is no carbon/soot buildup.
  5. Rich Exo generators typically operate at a 7:1 air to natural gas ratio. Below about 6.8 and lower ratios, soot/carbon deposits start appearing that require carbon burnout as part of the maintenance procedure.
Table C. Exo gas compositions in heat treat furnaces

Conclusions

A walkthrough of the entire cycle of gas production to cool down to use in the high heat section of the furnace clearly shows that as temperature changes, so does the Exo gas composition for any air to natural gas ratio.

Having a well-controlled composition of Exo gas requires the following:

  • Well-controlled composition of the natural gas used
  • Air supply with controlled dew point
  • Highly accurate air and natural gas mixing system
  • Highly controlled and maintained cooling system
  • A reliable ORP analyzer or the H₂ to H₂O ratio analyzer as part of the Exo gas delivery system.

Protecting metallic workpieces is paramount in heat treating, and in order to do this, the atmosphere created by Exothermic gas must be understood, both in the cool down phase and within the heat treat furnace. For further understanding of the good progress made in the improvement of Exo generators, see Dan Herring’s work in the reference section below.

References

Herring, Dan. “Exothermic Gas Generators: Forgotten Technology?” Industrial Heating, 2018, https:// digital.bnpmedia.com/publication/?m=11623&i=53 4828&p=121&ver=html5.

Morris, Art. “Exothermic Atmospheres.” Industrial Heating (June 10, 2023), https:// www.industrialheating.com/articles/91142-Exothermic-atmospherees.

About the Author

Harb Nayar is the founder and president of TAT Technologies LLC. Harb is both an inquisitive learner and dynamic entrepreneur who will share his current interests in the powder metal industry and what he anticipates for the future of the industry, especially where it bisects with heat treating.

For more information: Contact Harb at harb.nayar@tat-tech.com or visit www.tat-tech.com

Find Heat Treating Products And Services When You Search On Heat Treat Buyers Guide.Com

Exo Gas Composition Changes, Part 2: Cool Down and Use in Heat Treat Furnaces Read More »

Heat Treat Radio #105: Lunch and Learn: Batch IQ Vs. Continuous Pusher, Part 2

/ ATMOSPHERE AIR FURNACES TECHNICAL CONTENT, CARBURIZING TECHNICAL CONTENT, FEATURED NEWS, HEAT TREAT RADIO, MANUFACTURING HEAT TREAT TECH

Have you decided to purchase batch or continuous furnace system equipment? Today's episode is part 2 of the Heat Treat Radio lunch & learn episode begun with Michael Mouilleseaux of Erie Steel. Preceding this episode were Part 1 (episode #102) and a Technical Tuesday piece, so listen to the history of these systems, equipment and processing differences, and maintenance concerns before jumping into this episode about capability and throughput.

Doug Glenn, Heat Treat Today publisher and Heat Treat Radio host; Karen Gantzer, associate publisher/editor-in-chief; and Bethany Leone, managing editor, join this Heat Treat Today lunch & learn.

Below, you can watch the video, listen to the podcast by clicking on the audio play button, or read an edited transcript.

The following transcript has been edited for your reading enjoyment.

An Example: Carburizing (00:52)

Michael Mouilleseaux:  What we want to do here is just compare the same part, the same heat treating process, processed in a batch furnace and processed in a pusher.

Figure 1: Carburizing Load Example (Source: Erie Steel)

Here we’re just going to make an example:

Pusher Load Description (00:58)

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I’m going to take a fictious gear: it’s 2 ¾ inch in diameter, it’s got an inside diameter of an inch and a quarter, it’s an inch and a half tall, and it weighs 1.25 pounds. For our purposes here, we’re going to put these in a cast basket. For the furnace that we’re going to put them in, the basket size is 36 inches square — so, it’s 36 x 36. The height in this pusher furnace is going to be 24 inches; the inside dimensions of a 36-inch basket (actually it’s a 35-inch basket that sits on a 36-inch tray) is 32 ½ inches.

Michael Mouilleseaux General Manager at Erie Steel, Ltd. Sourced from the author

If I take 10 rows of parts — that’s 27 ½ inches — that gives me about a half inch between parts. That’s going to be our loading scheme. So, in one layer, it’s going to be 10 pieces of 10 rows of 10 pieces each; that gives us about a half inch between parts. It doesn’t matter why, that’s just what we’re going to do so that we have some standard to do that.

We’re going to say that this basket is 18 inches tall, so we’re going to get 7 layers of parts so that there’s approximately 1 inch between each layer of parts. This loading scheme gets us 700 pieces in a basket; it gets us 875 pounds net.

So the 36-inch basket that’s 18 inches tall and we’ve got 10 rows of 10 pieces, and we’ve got 7 layers of these things, so we have some room in between them. The reason for that is circulation of atmosphere and quenchant. This is what’s going to constitute the pusher load.

Batch Load Description (03:09)

Now, when we go to the batch load, we’re going to take four of these, because the batch furnace that we’re going to compare this to is going to be 36 inches wide and it’s going to be 72 inches long. We have two baskets on the bottom, 36, and then two of them is 72, and two on top. They’re 18 inches high, so 18 and 18 is 36 — a standard 36 x 72. It’s got 40 inches of height on it. I can take that 36 inches, put it on a 2 ½-inch tray and I can get it in and out of the furnace.

What is this four baskets? 2800 pieces in a load and 3500 pounds. That’s the difference. I’m comparing one basket, 700 pieces and 875 pounds and we’re going to compare that to what we would do if we ran a batch load, which is significantly more. It’s 2800 pieces and 3500 pounds.

What do we want to do with this?

Let’s say that we’re going to carburize this, and we want 50 thousandths case (total case depth of 0/050”). Now, I will show you very soon why we’ve chosen 50 thousandths case. Because at 1700°F (which is what we’re going to carburize at), the diffusion rate is 25 thousandths of an inch times the square root of time.

Now, I can do that math in my head. 25 thousandths times 2 is 50 thousandths. That means we need four hours. So, the part would have to be in the furnace for four hours, at temperature, carburizing, in order to achieve 50 thousandths case.

Figure 2: Batch IQ Carburizing Load (Source: Erie Steel)

Batch Furnace Time (04:59)

Let’s look at the next section. As we said, the furnace is 36 x 72 x 36 and we have 2800 pieces in the load. So, that is 1700°F. We’re going to say that there is 3500 pounds and there is probably another 800 or 900 pounds in fixturing so that’s about 4500 pounds. It’s very conservative; in a 36 x 72 furnace, you could probably get away with running 6,000 pounds. This is just a load that is well within the capability of that.

Furnace recovery is going to take two hours.

Doug Glenn:  Meaning, it’s going to take you two hours to get up to temperature.

Mike Mouilleseaux:  Until the entirety of the load is at 1700°F, that’s right. Inside, outside, top to bottom.

We’re going to carburize this at four hours, as we described previously; we calculated that and we need four hours to get our 50 thousandths case. Then we’re going to reduce the temperature in the furnace to 1550°F so that we can quench it.

So, we have two hours of furnace recovery, four hours at carburizing, two hours to reduce the temperature and attain a uniform 1550°F. That’s eight hours, and that’s what you would term an 8-hour furnace cycle.

We know that we have 2800 pieces in the load. In eight hours (2800 divided by 8) you’ve got 350 pieces/hour. That’s what the hourly productivity would be in this load.

We won’t talk about “what could we do.” There’s a lot of things that we could do. This is simply an example.

Pusher Furnace Time (07:05)

Now, in the pusher load, as previously described, it’s 36 x 36 and it’s 24 inches high. Now, we know that we have a basket that’s 18 inches high. Again, it’s going to sit on a 2-inch tray, so we’ve got 21 inches of the top of the basket that is going to fit in the furnace; there are going to be no issues with that whatsoever.

When we looked at the first description of that furnace, there were two positions in recovery, there were four positions to boost to diffuse, and there were two positions to reduce the temperature.

The controlling factor is that we want four hours at temperature. In the boost and diffuse, we have four positions. The furnace cycles once per hour.

We get one load size (700 pieces, 875 pounds) every hour. So, in this example (an 8-position, 36-square pusher) this process would yield 700 pieces an hour, and a batch furnace loaded as we described (same exact loading and number of pieces/basket) would yield 350 pieces/hour. In this scenario, the pusher furnace is going to produce twice the number of parts/hour that the batch would.

So, you would say, “Well, let’s just do that.” What you have to understand is that every hour, you are going to produce 700 pieces. If we went back and we looked at that description of what that pusher system looked like, you would see there are 23 positions in that. When I load a load, it’s going to be 23 hours before the first load comes out.

What we’re talking about is whether or not there were 700 pieces and 800 pounds, 23 of those[ET10] [BL11]  load.

The point would be, you either have to have enough of the same product or enough of similar product that can be processed to the same process to justify using something like this. Because if we want to change the cycle in the furnace. So, can we do that? The answer is absolutely, yes.

The preheat there, that stays at relatively the same temperature. The first zone in the furnace where we’re preheating the load, that temperature can be changed, as can the temperature in the boost diffuse and/or cycle time.

Figure 3: Pusher Furnace System (Source: Erie Steel)

So, in our example, we used an hour. What if you wanted 40 thousandths case and you’re going to be closer to 45 minutes or 50 minutes of time, how would you accomplish that? That can be done.

Typically, commercial heat treaters would come up with a strategy on how to cycle parts in and hold the furnace, or how many empties you would put in the furnace before you would change the furnace cycle.

Obviously, in the last two positions, where you’re reducing temperature, you could change the temperature in either the first two positions, where you’re preheating the load, or you could change the carburizing temperature, because when we’re dropping the temperature, it doesn’t have a material effect upon that.

Typically, in an in-house operation, you would not do that kind of thing, for a couple of reasons, not the least of which would be considering the type of people that you have operating these furnaces. They come in and out from other departments, and this is the kind of thing that you would want someone experientially understanding the instructions that you’ve given them. The furnace operator is not necessarily going to be the one to do it; this may be a pre-established methodology. You want them to execute that. But if you have somebody that is running a grinder and then they’re running a plating line and then they’re coming and working in the heat treat, that would not be the recipe for trying to make these kinds of changes.

As I described to you before, I worked in another life where we had 15 pushers. They were multiple-row pushers. We made 10,000 transfer cases a day. The furnace cycle on every furnace was established on the 1st of January, and on the 31st of December it was still running the same furnace cycle. You never changed what you were doing. The same parts went into the same furnaces and that’s how they were able to achieve the uniform results they were looking for.

Pusher Furnaces and Flexibility (12:45)

So, the longer the pusher furnace is, the less flexible it is.

In this example, you have eight. You know, there are pusher furnaces that have four positions. If you think about it, in a 4-position furnace, you could empty it out pretty quickly and change the cycle.

There are a lot of 6-position pusher furnaces in the commercial heat treating industry; that seems to be a good balance. The number of multiple-row pushers in the commercial industry, they’re fewer and far between. I’m not going to say they’re nonexistent, but enough of the same kind of product to justify that is difficult.

Doug Glenn: You could put two 8-stations in a pusher side by side so that there’s two baskets going through side by side or three baskets side by side, or four. That increases the productivity even more. There are multi-row setups.

Distortion, Quenching, and Furnace Choice (14:28)

I think the bottom line here is, for companies that are having high variability, low quantity, low volume loads, generally speaking, your batch is going to be good because it’s very flexible, you can change quickly.

However, with a company like the one you were describing where there is low variability and very high volume, pushers are obviously going to make sense. But there is a whole spectrum in between there where you’re going to have to figure out which one makes more sense — whether you’re going to go with a batch or a continuous.

Mike Mouilleseaux: Possibly underappreciated is the aspect of distortion.

Figure 4: Pusher Furnace Sequence (Source: Erie Steel)

In that carburizing example, you’d say, “We have an alloy steel, we’re aiming for 50 thousandths case — what’s the variation within a load?” And I’m going to say that it is going to be less than 5 thousandths, less than 10%. From the top to the bottom, the inside to the outside, it’s going to be less than 5 thousandths. That same process, in the pusher furnace is going to be less than 3 thousandths.

That’s one aspect of the metallurgy. The other aspect is quenching.

Doug Glenn: 5 thousandths versus 3 thousandths — 3 thousandths is much more uniform, right?

Mike Mouilleseaux:  Correct.

Doug Glenn: And that’s good because that way the entire load is more consistent (in the continuous unit, let’s say).

Mike Mouilleseaux:  That is correct.

Then there is the consistency in quenching. In the batch furnace, you’re quenching 36 inches of the parts. If we had seven layers in the pusher, we have 14 layers of parts in the batch. What are the dynamics involved in that?

We have experience that the ID of a gear (it’s a splined gear) in a batch furnace, we were able to maintain less than 50 microns of distortion. There is a lot involved in that, that’s not for free; there’s a fair amount involved in that and it’s a sophisticated cycle, if you will. That same cycle in a pusher furnace, same case depth, similar quenching strategy, will give you less than half that amount of distortion.

To the heat treater, where we’re talking about the metallurgy of this, you’re going to think 5 thousandths or 3 thousandths is not a big deal.

To the end-user, that reduction in distortion all of a sudden starts paying a number of benefits. The amount of hard finishing that has to be done or honing or hard broaching or something of that nature suddenly becomes far more important.

Doug Glenn:  Yes. That adds a lot of money to the total process, if you’ve got to do any of those post heat treat processes.

Mike Mouilleseaux:  To a large extent, that is due to the fact that you have a smaller load. If you have a smaller load, you have less opportunity for variation — it’s not that it’s all of a sudden magic.

Doug Glenn:  And for the people that don’t understand exactly what that means, think about a single basket that goes into a quench tank and four baskets, arranged two on top and two on bottom. The parts in the middle of that are going to be quenched more slowly because the quench is not hitting it as much.

So, the cooling rates on a stacked load are going to be substantially different than for a single basket, and that’s where distortion can happen.

Mike Mouilleseaux: There are a tremendous number of components that are running batch furnaces successfully. The transportation industry, medical, aerospace, military — are all examples. I’m simply pointing out the fact that there is an opportunity to do something but what we have to keep in mind is — how many of those somethings are there available?

The one thing you would not want to do is try to run four loads in a pusher furnace that could hold 10 because the conditions are not going to be consistent. The front end (the first load) has nothing in front of it so it’s heating at a different rate than the loads in the center, and the last load is cooling at a different rate than the loads that were in the center. That which I just described to you about the potential improvement in distortion, that would be negated in that circumstance.

Doug Glenn:  If you’re running a continuous system at full bore and you’re running a batch system at full capacity, especially when you get to the quench, there are a lot of other variables you need to consider in the batch.

This is simply because of the load configuration, and the rates of cooling from the outer parts — top, bottom, sides, as opposed to the ones in the middle. Whereas with a single basket, you still have to worry about the parts on the outside as they’re going to cool quicker than the parts on the inside, but it’s less so, by a significant degree.

Mike Mouilleseaux: Something that I have learned — which is totally counterintuitive to everything that I was educated with and everything that I was ever told— we’d always thought that it was the parts in the top of the load where the oil had gone through and had an opportunity to vaporize and you weren’t getting the same uniform quench—those were the parts that you had the highest distortion.

Counterintuitively, it’s the parts in the bottom of the load that have the greatest degree of distortion. It has very little to do with vaporizing the oil and it has everything to do with laminar flow versus turbulent flow.

Doug Glenn: In the quench tank, is the oil being circulated up through the load?

Mike Mouilleseaux:  Yes.

Doug Glenn:  So, supposedly, the coolest oil is hitting the bottom first.

Mike Mouilleseaux:  Yes.

Thoughts on the Future of Furnace Improvement (22:20)

Doug Glenn:  What about the future on these things?

Mike Mouilleseaux:  Where do we think this thing is going? Obviously, you’re going to continue to see incremental improvement in furnace hardware: in burners, in controllers, in insulation, in alloys. These things will be more robust; they’re going to last longer. If we looked at a furnace today and we looked at a furnace that was made 50 years ago, and we stood back a hundred yards, almost no one could tell what the difference was, and yet, it would perform demonstrably different. They are far more precise and accurate than ever.

For the process control systems, we’re going to see real-time analysis of process parameters. We don’t have that now. I think that machine learning is going to come into play, to optimize and predict issues and prevent catastrophic things.

Heating rates that we talked about: Why are we not going to see machine learning or AI finding the problem sooner, rather than my looking at it and seeing it a week later and thinking, “You know, it looks like these things are starting to take longer to heat up.” Why can’t that be noticed by some kind of machine learning or something like that?

In terms of atmosphere usage, if you’re running the same load, and you run it a number of times, the heating rate should be the same, and the amount of gas that you use to carburize that load should be exactly the same. But if you have a problem with atmosphere integrity — you got a door leak, you got a fan leak, or you got a water leak on a bearing — those things are going to change. Now, by the time it gets your attention, you could’ve dealt with that much sooner and prevented other things from happening.

"For the process control systems, we’re going to see real-time analysis of process parameters. We don’t have that now. I think that machine learning is going to come into play, to optimize and predict issues and prevent catastrophic things."

So, did it cause a problem with the part? By the time it causes a problem with the part, it’s really serious. The point is that there is something between when it initiated and when it’s really serious. With the right kind of analysis, that could be prevented. I think that that kind of thing is coming.

Motor outputs, transfer times — I see all of those things being incorporated into a very comprehensive system whereby you’re going to understand what’s happening with the process in real-time. If you make adjustments, you’re going to know why. Then you’re going to know where you need to go and look to fix it.

And last but not least, the integration of the metallurgical results in the process. Before you have a significant difference in case depth or core hardness. There are reasons that these things happen. Again, this machine learning, expert analysis, AI (whatever it is we’re going to call that) we’re going to see that that’s going to do it, and we’re not relying on somebody to figure why it’s happening.

The other thing I see happening in the future is all about energy and greenhouse gases. Our Department of Energy has an industrial decarbonization roadmap today, and it’s being implemented, and we don’t even know it. One of the targets in this industrial decarburization roadmap is reduction in greenhouse gases: 85% by 2035, net zero by 2050.

So, what does that mean? I’ve listened to the symposiums that they have put on. There are three things that they’re looking for and one is energy efficiency. I’m going to say that we’ve been down that road and we’ve beat that dog already. Are there going to be other opportunities? Sure. It’s these incremental things, like burner efficiency. But there is no low hanging fruit in energy efficiency.

The other thing is going to be innovative use of hydrogen instead of natural gas because the CO₂ footprint of hydrogen is much lower than that of natural gas. If you look at how the majority of hydrogen is generated today, it’s generated from natural gas. How do you strip hydrogen out of there? You heat it up with natural gas or you heat it up with electricity. Hydrogen is four times the cost of natural gas as a heating source.

The other thing that they’re talking about is electrifying. It’s electrify, electrify, electrify. The electricity has to be generated by clean energy. So, does that mean that we run our furnaces when the wind is blowing or the sun is out, or we’re using peaker plants that are run off hydrogen, and the hydrogen is generated when the sun is shining or the wind is blowing, and we’re stripping out the natural gas?

From what I, personally, have seen with these things, these are absolutely noble goals. You could not disagree with them whatsoever. The way that they want to go about accomplishing it, and the timeline that they wish to accomplish that in, is unrealistic.

If you look at how the majority of hydrogen is generated today, it’s generated from natural gas. How do you strip hydrogen out of there? You heat it up with natural gas or you heat it up with electricity. Hydrogen is four times the cost of natural gas as a heating source.

Doug Glenn:  Well, Michael, don’t even get me going on this! There are a lot of different things that are going on here but it’s good to hear you say this stuff. I agree with you on a lot of this stuff. They are noble goals; there is absolutely nothing wrong with electrifying.

Now, I do know some people — and even I would probably fall into the camp of one of those guys — that questions the premise behind the whole decarbonization movement. I mean, is CO₂ really not our friend? There’s that whole question. But, even if you grant that, I agree with you that the timeframe in which they’re wanting to do some of these things is, I think, fairly unrealistic.

It’s always good to know the reality of the world, whether you agree with it or not. It’s there, it’s happening, so you’ve got to go in with eyes wide open.

Safety Concerns (29:41)

Mike Mouilleseaux:  The safety concerns on these are all very similar. You know, the MTI (Metal Treating Institute) has some pretty good safety courses on these things, and I think there are a lot of people who have taken advantage of that. The fact that it’s been formalized is much better.

When I grew up in this, it was something that you learned empirically, and making a mistake in learning it, although the learning situation is embedded in you, sometimes the cost of that is just too great, so that the probability of being hurt or burnt or causing damage to a facility, is just too great.

There are definitely things that need to be addressed with that, and there are some very basic things that need to be done.

Doug Glenn: Michael, thanks a lot. I appreciate your expertise in all these areas, you are a wealth of knowledge.

Mike Mouilleseaux:  My pleasure. It’s been fun.

Doug Glenn:  You bet, you bet.

About the Expert:

Michael Mouilleseaux is general manager at Erie Steel LTD. Mike has been at Erie Steel in Toledo, OH since 2006 with previous metallurgical experience at New Process Gear in Syracuse, NY and as the Director of Technology in Marketing at FPM Heat Treating LLC in Elk Grove, IL. Having graduated from the University of Michigan with a degree in Metallurgical Engineering, Mike has proved his expertise in the field of heat treat, co-presenting at the 2019 Heat Treat show and currently serving on the Board of Trustees at the Metal Treating Institute.

Contact: mmouilleseaux@erie.com

 

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Heat Treat Radio #105: Lunch and Learn: Batch IQ Vs. Continuous Pusher, Part 2 Read More »

Sustainability Insights: How Can We Work to Get the Carbon Out of Heating? Part 1

/ BULK GASES & SYSTEMS TECHNICAL CONTENT, BURNERS & COMBUSTION SYSTEMS TECHNICAL CONTENT, FEATURED NEWS, MANUFACTURING HEAT TREAT TECH, OP-ED
op-ed

The search for sustainable solutions in the heat treat industry is at the forefront of research for industry experts. Michael Stowe, PR, senior energy engineer at Advanced Energy, one such expert, offers some fuel for thought on the subject of how heat treaters can reduce their carbon emissions.

This Sustainability Insights article was first published in Heat Treat Today’s December 2023 Heat Treat Medical and Energy print magazine.

Michael Stowe
PE, Senior Energy Engineer
Advanced Energy

The question in the article title is becoming increasingly popular with industrial organizations. Understanding the carbon content of products is becoming more of a “have to” item, especially for organizations that are in the supply chain for industrial assembly plants such as in the automotive industry. Many heat treaters are key steps in the supply chain process, and their carbon footprints will be of more interest to upstream users of heat treated parts in the future. I know I am overstating the obvious here, but I am going to do it anyway for emphasis:

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  1. Heat treating requires HEAT.
  2. HEAT requires ENERGY consumption.
  3. ENERGY consumption creates a carbon footprint:
    a. Fossil fuels heating — direct carbon emissions (Scope 1)
    b. Electric heating — indirect carbon emissions (Scope 2)

Therefore, by definition and by process, if you are heat treating, then you are producing carbon emissions. Again, the question is, “How can we work to get the carbon out of heating?” Let us explore this.

Figure 1. Methane combustion (Source: Advanced Energy)

Once more, heat treating requires energy input. The energy sources for heat treating most frequently include the combustion of carbon-based fossil fuels such as natural gas (methane), propane, fuel oil, diesel, or coal. Also, most combustion processes have a component of electricity to operate combustion air supply blowers, exhaust blowers, circulation fans, conveyors, and other items.

Figure 1 shows the chemical process for the combustion of methane (i.e., natural gas). Figure 1 demonstrates that during combustion, methane (CH4) combines with oxygen (O₂) to form carbon dioxide (CO₂) and water (H₂O). This same process is true for any carbon-based fuel. If you try to imagine all the combustion in progress across the globe at any given time, and knowing that all this combustion is releasing CO₂, then it is easy to see the problem and the need for CO₂ emission reductions.

In the most basic terms, if you have a combustion-based heat treating process on your site, then you are emitting CO₂. The electricity consumed to support the combustion processes also has a carbon component, and the consumption of this electricity contributes to a site’s carbon footprint.

Figure 2. The 4 Rs of carbon footprint (Source: Advanced Energy)

So, combustion and electricity consumption on your site contributes to your carbon footprint. Knowing this, organizations may want to consider the level of their carbon footprint and explore ways to reduce it. There are many methods and resources available to help organizations understand and work to improve their carbon footprint. For this article, we will focus on the 4 Rs of carbon footprint
reduction (see Figure 2).

We will discuss each of these approaches individually in priority order in the next installment of the Sustainability Insights.

For more information:
Connect with IHEA Sustainability & Decarbonization Initiatives www.ihea.org/page/Sustainability
Article provided by IHEA Sustainability

Find Heat Treating Products And Services When You Search On Heat Treat Buyers Guide.Com

Sustainability Insights: How Can We Work to Get the Carbon Out of Heating? Part 1 Read More »

Continuing the Dialogue: Michael Mouilleseaux on Batch/Continuous Furnace Maintenance

/ ATMOSPHERE AIR FURNACES TECHNICAL CONTENT, CONTROLS, CONTROLS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH / Leave a Comment

Our readers and Heat Treat Radio listeners will remember a recent episode entitled "Heat Treat Radio #102: Lunch & Learn, Batch IQ Vs. Continuous Pusher, Part 1." Today's Technical Tuesday article is a continuation of this dialog, with Michael Mouilleseaux, a boot-on-the-ground North American heat treat expert from Erie Steel here to answer your questions on the maintenance of batch and continuous pusher furnace systems.

Doug Glenn, Heat Treat Today's publisher, Karen Gantzer, associate publisher/editor-in-chief, join in this Technical Tuesday article.

Stay tuned for a Part 2 continuation of the Lunch and Learn Heat Treat Radio episode, coming to Heat Treat Radio in a couple weeks.

Below, you can watch the video or read from an edited transcript.

https://player.vimeo.com/video/900890450?badge=0&autopause=0&player_id=0&app_id=58479
Michael Mouilleseaux
General Manager at Erie Steel, Ltd.
Sourced from the author

Introduction to Maintenance

Doug Glenn: We would like to move on to maintenance of the batch furnace and the continuous furnace. What is the cost of maintaining and operating these furnaces?

Michael Mouilleseaux:  When they are utilized in a carburizing environment, there is always excess carbon that falls out or precipitates out of the atmosphere, and it ends up as elemental carbon in the bottom of the furnace.

What do you do with that? In furnaces that are using a carburizing environment, the burnout of the furnace is easily the single most important piece of preventative maintenance that you can perform. How is that performed? First, the furnace is vacated; there is no product in the furnace, the temperature is reduced — typically, you want it down around 1500°F or 1550°F — and you introduce room air into the furnace. The room air ignites the carbon. It’s a very primitive operation.

So, what temperature does carbon burn at? It burns at 3000°F.

You need to be very careful. It’s a controlled burn because you can actually damage the furnace through refractory, through the alloy that’s in the furnace, or it can get away. How do you do control it? On one level, you’re just looking at the temperature control. If you have it set at 1550, you’re going to say, “I’m only going to put air as long as the temperature of the furnace does not go up more than 25°F or 50°F.” It’s somewhat dependent upon the piece of equipment and is one of those things that you learn empirically; there is not a hard and fast rule for it.

Then, you can shut off the air. If there is no oxygen, then the source for combustion is taken away and you stop that operation. If you need to do it more rapidly than that, you may need to flood the furnace with nitrogen. Typically, if you have to flood the furnace with nitrogen to do it, you’ve been a little too aggressive in your burnout.

How long do you perform that? The great thing with oxygen probes is that you can utilize your oxygen probe to help you learn when you have burnt out the furnace. You’re not getting an actual carbon atmosphere, but what you do get is a readout from the probe. What you can do is perform the burnout operation until you attain that level and then you know that you’ve done a sufficient job in burning it out. That’s the single most important piece of preventative maintenance that’s done on a furnace used for carburizing.

Doug Glenn: Is that both in batch and in continuous?

Michael Mouilleseaux: Identical, yes.

Doug Glenn: I’ve got a couple other questions about furnace burnouts as someone who’s not a furnace operator. You said that there’s “carbon dropout” in the furnace. I know that in some furnaces, parts of the atmosphere may precipitate onto the coolest part of the furnace. Is that what is happening, or are we talking about carbon powder at the bottom of a furnace?

Michael Mouilleseaux: It is carbon powder, and it becomes more egregious. The powder then begins to accumulate into pebbles, nuggets, and larger size pieces. That’s more problematic. When it is in a powdered form, that is the best.

The question will be: How often do you have to do this? As with everything, the answer is — it depends. It depends on what you’re doing; it depends on how aggressive you are in your carburizing.

In the boost phase, we talked about carburizing at upwards of 1%. As soon as you exceed the saturation level of carbon, you’re going to precipitate out the excess carbon. What is that number? It’s different for every temperature. At 1500°F, it’s .9 or .85; at 1750°F, it’s 1.25. But to attain that, you’re actually putting natural gas into the furnace, and the amount of natural gas that you put into the furnace and its dissociation rate — the rate that it breaks down — can then subsequently be diffused into the parts; all of that comes into play.

With saturation levels of carburizing, there is always some residual carbon that’s in the furnace.

Doug Glenn: You mentioned that carbon burns at around 3,000 degrees. Are you taking the furnace up to that temperature?

The great thing with oxygen probes is that you can utilize your oxygen probe to help you learn when you have burnt out the furnace. You’re not getting an actual carbon atmosphere, but what you do get is a readout from the probe. What you can do is perform the burnout operation until you attain that level and then you know that you’ve done a sufficient job in burning it out. That’s the single most important piece of preventative maintenance that’s done on a furnace used for carburizing

Michael Mouilleseaux: No. The burnout cycle is at 1500 or 1550. You raise that carbon to that level and introduce oxygen, and what you want is a slow burn.

We next think about the systems involved in the furnace. First there is the heating system. In a gas-fired furnace, some critical things to consider are burner recovery, burner adjustment, and the amount of excess air that results in that burner adjustment. That’s a preventative maintenance operation that needs to be performed on a regular basis. It probably doesn’t need to be done daily, but monthly is optimal. If everything is very steady, including the barometric pressure, then you don’t need to do all of those adjustments.

Now, electric furnaces have SCRs that fire the elements, and you have to pay attention to the tuning of those things to make sure that they’re operating at optimum performance. One of the ways that you can do that, in a batch furnace, is if you look at the recovery time.

For example, if you have a load that weighs 4000 lbs. and you put it in the furnace and you know that it takes an hour and a half for the furnace to recover to temperature, but then all of a sudden, it takes an hour and 45 minutes, or an hour and 50 minutes, or two hours, obviously the burners are not producing the same amount of heat. The burners are not pumping the requisite amount of BTUs to achieve that recovery time. Could that be related furnace circulation? Could it be related to the insulation in the furnace? At an extreme, it could. Typically, though, it’s related to burner or SCR tuning.

Those are the kinds of things that are very easy to pay attention to.

"Electric furnaces have SCRs that fire the elements, and you have to pay attention to the tuning of those things to make sure that they’re operating at optimum performance. One of the ways that you can do that, in a batch furnace, is if you look at the recovery time."

Setting up PM Through Controls System

The control schemes in the PLC are typically very robust. So, you can establish a program and the PLC is going to say, “I want to heat it at this rate, I want the carbon potential to be .4%, I want to hold this at two hours at temperature, and then I want to initiate a quenching cycle.” Typically, PLCs are quite robust.

The thing you have to be careful with is obviously not just power outages, but brownouts. Brownouts are when you don’t quite lose all voltage, but you lose some of it. If you don’t have some kind of a filter on the power you can mitigate with, or have an uninterruptable power supply for the PLC, you can damage those things, resulting in some major work on the PLC.

The other part of that is the furnace circulation. We’ve got fans in these furnaces, and we circulate the atmosphere. The primary stages of heating in the furnace are convection, until we get to 1200 degrees. How do we convect the heat? We have the atmosphere in the furnace, the fan circulates, it washes the atmosphere down the radiant tubes, it heats up the atmosphere, the atmosphere comes into contact with the components, and we’re convection-heating the parts.

Once we get to 1200 degrees or more, then the primary method of heating becomes radiant heating. That’s where the radiant tubes are then the primary means of transferring energy. But the fans become very important. Are they balanced? Is the RPM correct? Is the amp reading on the fan? Those are areas to look at.

You have to understand how the furnace operates when it’s healthy — the furnace manufacturer can help you and/or you just learn empirically. For instance, what would it mean if, all of a sudden, I’m drawing much fewer amps on a circulating fan and it’s running very rough? Quite possibly, we’ve lost a fan blade.

Then there is the atmosphere control system. All that we just described is applicable to both continuous and batch furnaces. The furnace needs to be sealed and you want a couple inches of water column pressure — excess pressure — in the furnace relative to atmosphere pressure, since safety is the number one concern.

The atmosphere that we’re talking about in most of these furnaces is endothermic atmosphere. It’s a reducing atmosphere, meaning that it’s combustible. If, of course, we have combustion in a closed vessel, that’s called an explosion.

The reducing atmosphere, in and of itself, is if you look in a furnace that is at anything above 1200 degrees where it’s red, up to 1700–1800 degrees where it’s going to be yellow to white — and there is no flame . . . . People are absolutely amazed when they look in an atmosphere furnace and they see no flame. What you should see is everything in a relative, uniform color. The parts should be a uniform color. If you look at the tubes, they should be a little lighter because the tubes will always be somewhat above the temperature of the parts . . . .

Back to the atmosphere: We want to be sure that the atmosphere stays in the furnace and that we maintain that pressure in the furnace. So, what would be a cause to lower the pressure in the furnace? A door leak or a leak in a fan. It could be, if you have a mechanical handling system, a leak through that system. Those are all places to look.

The PM on that? For maintaining the level of lubrication in the fan bearings, see that they’re cooled so that the outlet temperature of the coolant — be it air or water — should be higher than the inlet temperature; that shows that they’re being cooled.

I can’t tell you an absolute number, but I can say that for the equipment that we have, we have numbers that we’ve developed; we know that if the outlet temperature of the water is 20 degrees higher than it is going in, we’re doing a good job of cooling the bearings.

The door seals in furnaces, typically, are brick on brick. Typically, they use a wedge system to seal the doors in the furnace. But, of necessity, these are wear items. Therefore, in preventative maintenance, you might notice a burnout around a door where you hadn’t had one before. That tells you that atmosphere is leaking out of that door and so a repair is needed in the near future.

An interesting thing about a batch furnace: Most of them only have one door. So, it’s quite easy — you can open the vestibule and, in a maintenance operation, if you gassed up the furnace, you could see.There is always going to be some atmosphere coming around the door because that’s where the atmosphere goes into the vestibule, but it should be at the top; it shouldn’t be around the sides, and it definitely shouldn’t be at the bottom. It should be very consistent.

That’s one of those things that, again, you empirically learn. You look at it — it’s a visual operation to say what you’re doing.

There are two other systems: First, the quench system. We talked about how critical the quench system is. The RPMs of the prop, the amp draw of the motors for the props — those things should be very consistent. I think they should be monitor and data logged. The reason for that is you want to know when you quench a load that the RPMs of those props are what you have set it for. When you introduce a load into the quench, the amp draw is, of necessity, going to increase. That’s because you’ve put something in the path of the quenchant so, in order to maintain that flow, you’ve increased the amount of work that it takes to rotate those props.

That’s the kind of thing that you want to monitor. If the amp draw is changing, that means that there’s something in the quench system. Could it be the bearings? Could it be the motor? Those are some things that you’d need to take a look at and be certain of. Obviously, the props need to be in balance; you don’t want any vibration in them.

Doug Glenn: This is also true on the continuous furnace. You’ve got three or four green props in the batch furnace, and it would be the same in the continuous furnace.

Source: Erie Steel, Ltd

Maintenance of Quenchant

Michael Mouilleseaux: Also, there is the maintenance of the quenchant. I’m of the belief that the quench should be continuously filtered. I’m not a fan of batch filtering. I’ve been doing this long enough that I’ve done that, and it just isn’t successful. Quite possibly there are operations that allow it.

If you’re carburizing, you’re going to have particulate in the quenchant because that same atmosphere precipitation of carbon finds its way into the quench. It’s going to be on the parts, it’s going to be on the trays, it’s going to be dragged in there. So, you have this particulate carbon in the quench and it acts as a catalyst to break down the oil.

One way to extend the life of the oil is to make sure that you’re continuously filtering that out. People say 50 microns or 100 microns or 25 microns. Experientially, I’m going to say that it’s going to be 25 microns. If you have a 100-micron filter, that’s great for getting the pebbles out of the quench or the scale, if that were to be an issue with your customer’s parts, but that’s not sufficient to filter out the particulate that’s going to be of the size that’s going to catalyze the breakdown of your quenchant.

Doug Glenn: I assume that if you’re providing for some sort of continuous filtering of your quench, that’s built into the quench structure. The quench tank is built for that, right, and you’re continually flowing it through this filter?

Michael Mouilleseaux: I’m not going to say that no manufacturers offer sufficient quench filtering, but I am not aware of anyone that offers a quench filtration system that’s sufficient. Most of these things end up being standalone. You want to draw the quenchant from the bottom of the tank in one quarter, you want to put it through a series of filters, and you want to put it back into the furnace at the opposite end of the quench tank.

I can say with certainty, that a batch furnace which has not been filtered well, if you remove the quenchant from the furnace after six months — definitely after 12 months — of using it in daily carburizing, you’re going to take 55-gallon drums of sludge out of the furnace, and the sludge is essentially carbon that’s mixed in with the oil.

For that same furnace, with a sufficient quench filtration system, there will be little pockets in the four corners of the quench tank, but that’s about it.

CQI-9, Nadcap and all of those standards have a requirement for monitoring of quenchant. One of the monitors should be particulate because that lets you know how good a job you’re doing in filtering.

Having done it properly, one can say, “Well, I have to replace my quench oil,” — fill in the blank — “once a year, once every six months, once every two years.” Properly maintained and filtered, the quenchant does not have to be replaced very often.

You’re going to drag out a little oil on every load. You want to let the load drip so that you’re not taking that precious quench oil and just putting it in the wash and washing it off. But in a batch furnace, you could have a couple hundred gallons a month to four hundred gallons, depending on the size of the furnace, of add-back that you’re putting in there. Is that sufficient to maintain all of the additives that are in the quenchant? Is that something that you need to monitor? Typically, the manufacturer can do that for you. You get monitoring and you see what the quench speed is, what is the viscosity, flash – all of those important pieces of information.

Now, it doesn’t come for free. A filtration system is costly, and the filters are costly. A year’s worth of quenchant is five years’ worth of filters. In my mind, that’s a good tradeoff.

Karen Gantzer:  So, Michael, when the process is filtering the quench, does this happen during production downtime?

Karen Gantzer
Associate Publisher/ Editor in Chief
Heat Treat Today

Michael Mouilleseaux:  No, it’s done continuously. Even when the furnace is not running on the weekend, you’re still filtering the oil. You’re going to be taking 20-50 gallons out of the quench tank but you’re putting it right back in. It just passes through filters.

Some people have utilized centrifuges. It’s a very successful way of filtering out carbon particles in oil. The caveat on that is you don’t want the oil above 140 degrees. If you get the oil above 140 degrees and for every 20 degrees you go up, you start doubling the oxidation rate of the oil.

In high-temperature oil, we do a fair amount of modified marquenching. We do it in closed canisters. The seals must be temperature-tolerant, but it is very successful.

The last part is going to be the quench heating and cooling. Typically, at the first part of the week when you’re starting up the furnace or if you’re going from operation A to operation B and it requires a higher temperature quenchant, you’re going to use either gas or electric elements that are going to heat it. Those things need to be monitored so that they’re available when you need them. The last thing that you want to do is start out the week and find out that the quench heaters don’t work; then, you’re trying to find a couple of dummy loads that you can heat up to put into the quench to heat up the quenchant before proceeding with operations.

Then, of great, importance is quench cooling. In petroleum-based quenchants, you’ve got a flashpoint of 400 degrees plus or minus — could be 350, could be 450, depending upon the quenchant that you’re using. You don’t want the temperature of that oil to approach that flashpoint. You do that by using a quench-cooling system. It’s a big radiator. You’ve got a pump, and you set it when you want the pump to go on. You pump the oil out to the quench coolant, and when it comes back, once you’ve attained what your temperature is, then you stop.

Doug Glenn: I’ve got a couple quick questions on this. First, is the quench heater an immersion tube?

Michael Mouilleseaux: Yes. Gas-fired tubes and gas-fired units are very small u-tubes that go into the quench tank. Electrical units have got elements that are tolerant to that.

Doug Glenn: Typically, you’re using those because you’re actually using the quenchant and always putting hot things into it, so once the quench fluid is up to temperature, it’s not a problem. You’re using that quench heater just to get the thing up to temperature. So after that, most of the time, you’re using the cooler to keep it cool, correct?

Michael Mouilleseaux: Absolutely. That’s a control scheme. The last thing that you want to do is set the quench heater so that it’s within five degrees of setpoint and set the quench cooling so that it’s within five degrees of setpoint — then, the temperature just sits there, with heating and cooling fighting each other. You’re heating and cooling oil unnecessarily. You want to give yourself some bandwidth on that.

Material Handling System

Last is going to be the material handling system. In the batch furnace, many have what we call a “rear handler.” We saw the cart and it would push the load into the vestibule, the inner door would open, and it would push the load into the furnace. It’s always preferable to push hot loads, not to pull on them. The reason is that the base trays are alloy and the compressive strength is much higher than the tensile strength is. If you’re pulling on loads, you’re going to break trays.

Once the load is in the furnace, you would have a rear handler so when the cycle is terminated and the inner door opens, you would have a mechanism — it may have a flat bar that’s half the width of the tray — that actually pushes the load into the quench vestibule.

There it’s pushed by the charge car and the inner door is open. That same handler, from the charge car, pushes it into the furnace. Now, when the cycle is terminated, there is a handler in the rear of the furnace that pushes it into the vestibule for quenching.

The exception is right here: When it’s taken out of the vestibule, typically the charge car goes in and grabs it and pulls it out. But, at that point, you’re at 100 or 200 degrees so, at that temperature, you have no material effect upon the strength of the alloy.

Doug Glenn: Okay, the motion it took it from the tray on the left inside is going to push it in and then the next step it’s also going to push it into this “hot zone,” correct?

Michael Mouilleseaux: Yes.

Doug Glenn: But what you’re saying is, when it’s coming out of the hot zone, there’s probably a mechanism on the far righthand side of the hot zone that’s going to push it back. Nothing is going in to pull it out because it’s hot.

Michael Mouilleseaux: Extended reach cars put the load into the vestibule and then put it into the hot zone.

There are some rear handlers that, rather than being a simple push function, have a dog mechanism that allows them to go and get the load in the vestibule and pull it into the furnace. Personally, I am not a fan of that; I like the extended reach car because when you’re pushing something, it is very easy to determine if you’ve put it in the right location. If you grab a load and pull it, you could lose the attachment on that load and then it’s not put exactly where you want it to be.

You can put amp meters on these things so that the amount of force that the motors require to pull in or push out a load. The one thing you need to be cognizant of is that it’s going to take more power — a higher amp draw — to push a 4000-pound load than it is a 2000-pound load. Once you understand what that is, you can monitor these furnaces and then they start making sense to you.

Source: Erie Steel, Ltd

 

Continuing the Dialogue: Michael Mouilleseaux on Batch/Continuous Furnace Maintenance Read More »

An Overview of Case Hardening: Which Is Best for Your Operations?

/ CARBURIZING TECHNICAL CONTENT, FEATURED NEWS, HARDENING, HARDENING TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, NITRIDING TECHNICAL CONTENT, NITROCARBURIZING TECHNICAL CONTENT
Best of the Web

Source: Advanced Heat Treat Corp.

Case hardening is an essential process for many heat treating operations, but knowing the different types and functions of each is far from intuitive.

In this best of the web article, discover the differences between carburization, carbonitriding, nitriding, and nitrocarburizing, as well as what questions you should ask before considering case hardening. You will encounter technical descriptions and expert advice to guide your selection of which case hardening process will be most beneficial for your specific heat treat needs.

An excerpt:

Case hardening heat treatments, which includes nitriding, nitrocarburizing, carburizing, and carbonitriding, alter a part’s chemical composition and focus on its surface properties. These processes create hardened surface layers ranging from 0.01 to 0.25 in. deep, depending on processing times and temperatures. Making the hardened layer thicker incurs higher costs due to additional processing times, but the part’s extended wear life can quickly justify additional processing costs. Material experts can apply these processes to provide the most cost-effective parts for specific applications.

Read the entire article from Advanced Heat Treat Corp. by clicking here: "Case Hardening Heat Treatments"

An Overview of Case Hardening: Which Is Best for Your Operations? Read More »

Trending Market Insights for Aluminum Thermal Processing

/ ALUMINUM PROCESSING TECHNICAL CONTENT, HEAT TREAT NEWS, HEAT TREAT NEWS INDUSTRIES, MANUFACTURING HEAT TREAT, MANUFACTURING HEAT TREAT TECH

Are there rapid changes in the North American aluminum industry to accommodate trending technology, or does the aluminum market have a different focus? Enjoy this Technical Tuesday article, in which six industry players responded to the following survey from Heat Treat Today’s editorial team in August 2023.

Steady and Increasing Melters’ Demand

Contact us with your Reader Feedback!

Is demand increasing or decreasing for aluminum processing/melting equipment?

AFC-Holcroft: “Yes, we continue to see opportunities for a variety of furnaces for T5, T6, and other aluminum heat treating processes. We recently signed a license agreement with Sanken Sangyo in Japan to offer their aluminum rotary furnace designs in the U.S. and Canada.”

Can-Eng Furnaces Intl., Ltd.: “Yes, particularly in finished component heat treatment systems (T4, T5, T6, and T7 processes). The processing demand is coming from new vehicle (ICE, hybrid, electric) model line-ups that are focusing heavily on lightweighting body in white (BIW), structural, and suspension components that are being converted from steel to aluminum.”

Lindberg/MPH: “We have seen an increase in aluminum scrap melting in the recent past with larger capacity melters being quoted.”

Premier Furnace Specialists: “We’re seeing a steady demand for aluminum processing equipment. Typically, our clients are requesting either aluminum solution furnaces, drop bottom furnaces, or pre-heat furnaces. There has been an increased demand for larger furnace chamber sizes and heavier load capacities as more customers are requesting furnaces that can handle a variety of materials, temperature ranges, and processes. It seems the aerospace industry is driving most of the demand at the moment.”

SECO/WARWICK: “On the molten metal side of the SECO/WARWICK business, there are a few significant projects out there which are active, and the level of inquiries is good!”

Wisconsin Oven: “We have seen an uptick in aluminum solution treat and aging equipment in recent years.”

Tracy Dougherty
Chief Operating Officer
AFC-Holcroft LLC
Tim Donofrio
Vice President of Sales
Can-Eng Furnaces International, Ltd.
Kelley Shreve
General Manager
Lindberg/MPH
Jacob Laird
Mechanical Engineer
Premier Furnace Specialists, Inc./BeaverMatic
Dan Peterson
Product Manager
Molten Metal Furnaces
SECO/WARWICK Corp.
Mike Grande
Vice President of Sales
Wisconsin Oven Corporation

AM/3D: Allusive Adoption

Has additive manufacturing/3D printing contributed to current business levels?  

AFC-Holcroft: “It’s been an ongoing topic, but volumes are still low, which has kept heat treating equipment investments at a minimum.”

Can-Eng Furnaces Intl., Ltd.: “No noticeable increase.”

Lindberg/MPH: “There have been more requests than in the past few years for sintering applications which, I believe, is largely driven by the increase in 3D metal printing manufacturing.”

Premier Furnace Specialists: “The company has been receiving a number of requests for smaller batch style ovens for the processing of additive manufactured/3D printed materials. We have also fulfilled a number of requests to alter existing or used systems to meet new process requirements.”

SECO/WARWICK: “On the molten metal side, this would be what we call the powdered metals industry, we has not seen much interest in that area this year. One exception is an inquiry that our sister company Retech was fielding.”

Wisconsin Oven: “No contribution.”

Adaptations To Slow Supply Chains

Have international supply chain disruptions impacted demand for your company’s equipment?

AFC-Holcroft: “There are certainly disruptions, but we’re finally starting to see some improvements. Our team has worked hard to mitigate the supply chain challenges through unique forward-looking programs with our suppliers and clients. As far as demand goes, it has not had an impact at all. In fact, we are currently experiencing booking levels that we haven’t seen in more than 20 years.”

Can-Eng Furnaces Intl., Ltd.: “Clients are planning ahead to address the longer lead times.”

Lindberg/MPH: “We have noticed that supply chain issues in general, both domestic and international, have created an environment where lead times to build equipment have more than doubled. This has caused many clients to begin looking for alternative solutions to meet their needs, as they cannot wait two-thirds of a year for equipment. The largest delays are with refractory, gas burners, alloy, and many various control components.”

Premier Furnace Specialists: “Actually, we’ve seen an increase in demand for our equipment from various industries impacted by disruptions. Many companies seem to be reassessing their supply chains and expanding production capacity to avoid future disruptions.”

Dual pit furnace and water quench tank system designed and built for a client in the aluminum castings industry. It is used for aluminum solution heat treating of thick walled castings. Each furnace has a 4,000 pound gross load capacity and an operating temperature range of 300°F – 1100°F. (Source: Premier Furnace Specialists/BeaverMatic)

SECO/WARWICK: “Lately our clients are for projects that are further out, 1–2 years in some cases. Most of our end users are aware that prices are still moving up and deliveries are stretched out, however there have been some improvements of deliveries on MCC’s and PLC’s.”

Wisconsin Oven: “Not that we know of.”

The State of Sustainability in Aluminum Market

Has the sustainability push affected demand for your equipment?

Horizontal quench system used for the solution treatment of aluminum parts (Source: Wisconsin Oven)

AFC-Holcroft: “Again, no impact on demand, but our group has been offering many ‘green’ options on our equipment for years to assist our clients in the drive for a reduction in their carbon footprint.”

Can-Eng Furnaces Intl., Ltd.: “Yes, there’s more emphasis on reduced environment impact processes and equipment designs.”

Lindberg/MPH: “Not really. We have had a couple of RFQ[ET7] ’s come in related to green energy, but they are very slow-moving projects with a lot of R&D on the buyers’ end. Additionally, we have been asked to partner with these clients to develop a solution to help them meet the end goal.”

Premier Furnace Specialists: “For a minor segment of clients, the push for sustainability seems to be driving a demand for electrically heated equipment rather than natural gas. Even for those clients, however, the main deciding factors are still local utility costs, existing facility restrictions, and familiarity with existing equipment.”

SECO/WARWICK: “Environmental sustainability has definitely affected what our clients are looking for on most new inquires. Most have strict emissions requirements and are looking for combustion systems with lower NOx and higher fuel efficiency. Peripheral hooding is also commonly requested to capture emissions from around door openings and over charge wells. I would not say that sustainability has diminished the demand, however it has affected what they need with regard to emissions compliance.”

Wisconsin Oven: “Clients occasionally request energy-efficient features and designs, but not more often than in the past.”

Anticipating Growth and Novel Aluminum Applications

What plans are you making to meet future market demand? 

AFC-Holcroft: “We are a global group and have recently restructured our organization to better serve our customers. We have also undergone a facility expansion to help reduce our carbon footprint and provide our clients with the best products and deliveries available in the market. This includes an expansion of our build to stock production planning to greatly reduce lead times on UBQ furnaces and EZ endothermic generators among other products.”

Can-Eng Furnaces Intl., Ltd.: “We have increased emphasis on electric battery vehicle component and materials processes and equipment design development. Additionally, we are planning further use of electric energy as an alternate heating source for system designs.”

Lindberg/MPH: “We are looking to work with vendors to create vendor managed inventory in order to reduce lead times, as well as hire additional employees to reduce labor driven lead times. We continually look for additional vendors to remain cost competitive and reducing the overall cost of manufacturing.”

Premier Furnace Specialists : “We’ve expanded vendor and supplier listings. We have also gained experience implementing existing and new alternatives for almost all of our furnace components. By reassessing our standard component choices and offering a variety to clients, we have been able to substantially reduce lead times which allows for more efficient and flexible production while reducing costs.

“We have also added new technology to aid in our manufacturing. Building parts in-house significantly cuts down on lead times and pricing. Thus, clients know that their equipment will have little or no downtime, saving them the time and stress of not running product.”

SECO/WARWICK: “We are adding engineers, field service technicians, etc. and having our “seasoned veterans” bring them up to speed! We have also moved to a larger new office location to accommodate future growth.”

Wisconsin Oven: “We have acquired additional floorspace in recent years and have been hiring aggressively in the last six months.”

About the Industry Experts

Tracy Dougherty, Chief Operating Officer, AFC-Holcroft LLC. tdougherty@afc-holcroft.com

Dan Peterson, Product Manager, Molten Metal Furnaces, SECO/WARWICK dan.peterson@secowarwick.com

Tim Donofrio, Vice President of Sales, Can-Eng Furnaces International, Ltd tdonofrio@can-eng.com

Kelley Shreve, General Manager, Lindberg/MPH https://www.lindbergmph.com/

Jacob Laird, Mechanical Engineer, Premier Furnace Specialists, Inc./BeaverMatic jlaird@premierfurnace.com

Mike Grande, Vice President of Sales, Wisconsin Oven Corporation www.wisoven.com

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3 Top Tips for Brinell and Rockwell Hardness Tests

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OC

Accurate hardness testing is a critical business for numerous industries, not least heat treatment. In this guide, we will offer our “best practice” list for getting the best possible reading for your hardness test with the most efficiency.

This Technical Tuesday article was written by Alex Austin, the managing director at Foundrax Engineering Products Ltd.  

1. Tip for All Tests 

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Alex Austin
Managing Director
Foundrax Engineering Products Ltd.
Source: Foundrax

Make sure the test equipment is properly set up. In most instances, this involves keeping the test machine serviced and calibrated in accordance with the international standards (ASTM E-10 for Brinell and ASTM E-18 for Rockwell) or the manufacturer’s instructions — whichever are more strict — along with mounting it on a level, vibration-free surface. The absence of vibration is crucial if you are using a lever and weight machine, but still desirable for hydraulic and motor-driven types, and it is mandated by the standards. 

It is worth noting that for tests made using portable Brinell hardness testers that apply the full test load (albeit without the ability to maintain it uninterrupted for the full ten seconds), while it might not always be possible to mount the machine on a solid and level surface, the rest of the above still applies.  

If the anvil is mounted on a leadscrew, ensure that it is properly secured. Similarly, jigs should be in good condition, correctly mounted and hold the test piece securely. It is easy to become very relaxed about the amount of energy that goes into applying 3000 kg to a 10 mm ball, but if the component shatters under load the results can be dramatic and, potentially, very dangerous. 

Don’t forget your safety boots!  Also, as fingerprint residue is corrosive, always wear gloves.

2. Brinell Hardness Testing 

Preparation 

Before performing a Brinell hardness test, make sure both the test area and the indenter ball are clean and free of all lubricants. Oil or grease on the test surface or indenter could wreck the test by lubricating the path of the indenter, making a very significant difference to the apparent hardness level. For example, at 300 HBW the material may appear around 20 HBW softer than it actually is. Moreover, it can change the appearance of the indentation edge, causing a false diameter measurement. In any case, the hardness standards are clear that test pieces must be clean and lubricant-free. 

Prepare the area of the component surface where the test is to be carried out so that the indenter comes into direct contact with the core material. For this, the skin must be removed, including any decarburized layer, using a hand grinder with 60 grit abrasive (or finer, if appropriate) in 3–5 seconds, if a good automatic Brinell microscope will measure the indentation, or 10–15 seconds for a good manual microscope. This time differential is on the basis that a good automatic system will measure hundreds of diameters and ignore grinding “noise” when identifying the true edge of the indentation. On the other hand, use of a manual microscope is limited to the number one can reasonably measure by the time available and the equipment at hand. However, in the case of both automatic and manual testing, the better the surface, the better the result.    

Next, place the material on the test machine’s table or anvil. Ensure that it is stable and cannot move under the test load (machines with an integral clamp are preferable from this point of view). The clamp should be holding the material so that the test surface is perpendicular to the indenter’s line of operation.  

Carrying Out the Brinell Hardness Test

Table A. Force-diameter indexes for different materials

Use the correct force-diameter index (F/D²) for the material being tested; see Table A.

Apply the test force in accordance with ISO6506 or ASTM E-10, as appropriate. While the indenter is in downward motion and in contact with the material, avoid doing anything that might create vibrations that could reach the machine. When the indenter has withdrawn, measure the resulting indentation in a minimum of two diameters perpendicular to each other and convert the mean measurement into an HBW number.  

If using a portable Brinell hardness tester, exercise caution when removing the machine from the component so that the edge of the indentation is not accidentally damaged when the machine is released.  

3. Rockwell Hardness Testing

Preparation 

Figure 1. Close-up of Rockwell indentation

Cleanliness is everything in Rockwell testing. The indenters are much smaller than those used in Brinell testing and (as you would expect) so are the indentations (see Figure 1). And because the Rockwell test measures indentation depth, not width, any contaminant or particle that gets between the indenter and the material is a problem. Underside contamination is almost as important. There have been instances of clients finding that the testing block seemed to render two hardness points lower than we stated, yet in every instance, we found a buildup of soft contaminants (e.g., grease, oxides, micro-swarf) on the underside of the block. These contaminants “give” as the indenter is driven into the block, thereby permitting further indenter travel than would occur in the block material alone.

Lubricant contamination on the block surface is obviously extremely problematic. All blocks should be cleaned with a cloth and a liquid solvent that leaves minimal residue (e.g. isopropyl alcohol). Tissue paper can be used for cleaning but can scratch aluminum and brass easily; untreated cotton wipes are preferable. The anvil should also be cleaned by gentle application of a lint-free cloth dampened with solvent, and the indenter itself should be gently wiped at intervals throughout the test session. Another place where contaminants can build up (easily producing an error in excess of one Rockwell point) is the mating face where the indenter holder is inserted into the test head of the machine (see Figure 2). 

Figure 2. Importance in preparation

It is obviously also essential that the anvil mount cannot budge under the indenting load. If it is mounted on a vertical threaded column, the column should be free of excess grease and tightened to the point of no movement. Column “give” is another area where we have detected consequential erroneous readings.  

A further notable check worth performing is that the block, or test piece, has not been dropped and landed on a corner of the underside, which would leave a burr. This would prevent the piece from sitting flush on the anvil and probably negate the possibility of correct readings, as the piece would move under the indenter load. 

Procedure 

Figure 3. Softer block placed over test material during Rockwell test

If the first indentation on a block suggests a lower hardness than the remainder, there is a chance that air was trapped underneath it. The first indentations usually drives any air out, but in the case that air remained trapped beneath the indenter, the hardness reading will be falsely soft; the block will have moved downwards as it displaced the air, and the indenter will, therefore, have travelled further than if the block were truly sitting flush on the anvil. Placing a block that is softer than the test material on top of the test block and putting one indentation into it before commencing the tests will eliminate this problem (see Figure 3). 

Have an aerosol duster to hand during indenting to keep the block surface clear. 

Test blocks should, ideally, be stored in airtight cases to reduce the rate at which oxides form on their surfaces. Better still, wrap them in rust-reducing paper as well.   

(Photo Source: Foundrax Engineering Products Ltd.) 

About the Author: Alex Austin has been the managing director of Foundrax Engineering Products Ltd. since 2002. Foundrax has supplied Brinell hardness testing equipment for 60+ years and is the only company in the world to truly specialize in this field. Alex sits on the ISE/101/05 Indentation Hardness Testing Committee at the British Standards Institution. He has been part of the British delegation to the International Standards Organization advising on the development of the standard ISO 6506 “Metallic materials – Brinell hardness test” and is the chairman and convener for the current ISO revision of the standard.

For more information:

Contact www.foundrax.co.uk

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It’s Time for Another Look at Vacuum Oil Quenching

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Oil quenching can be a dirty phrase around the heat treat shop. But with vacuum, does it have to be?

This Technical Tuesday article was written by Don Marteeny, vice president of engineering at SECO/VACUUM Technologies, for Heat Treat Today’s November 2023 Vacuum Heat Treating print edition.

There are metallurgical advantages to oil quenching for which there are no gas quench substitutes, but for a time, those advantages only came bundled with some disadvantages that proved incompatible with a growing preference for vacuum processes. This drove vacuum oil quenching (VOQ) to evolve and improve, often faster than its reputation. VOQ has since matured into a convenient, safe, and economical choice, offering today’s vacuum heat treaters all the metallurgical advantages of oil quench without any of the compromises.

A Familiar Scene . . .

Don Marteeny
Vice President of Engineering
SECO/VACUUM Technologies
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When oil quenching is mentioned in the break room of any heat treat department, it’s a sure bet that those listening have very similar thoughts. With just the mere mention of oil, their thoughts carry them, not to memories of the first time they helped their dad change the oil in their car in the family garage, but instead to a row of furnaces belching flames from their doors. Next, they are sure to see one of the doors open, and the familiar sensation of hot air moves through their mind. They may – for a moment – expect the smell of salt air, the sand between their toes, and the sun from above.

For many heat treaters, this is but a momentary escape. Soon, the taste and smell of hot oil and metal return them to the moment, and they know they are standing next to a row of batch integral quench (aka, batch IQ or BIQ) furnaces.

It’s about then they will feel the heat of those flames at the end of this furnace line or by the transfer car, wiping the sweat from their brow with a sooty hand and anticipating a return to the break room for a cool drink of water.

Sound familiar? If so, you’re one of the hundreds of heat treaters who has had the pleasure of operating a tried-and-true atmosphere integral quench line; it faithfully does its job, hardening and case hardening steels where oil is the only heavy lifter that can do the job.

Figure 1. Atmosphere oil quenching
Source: SECO/VACUUM Technologies

Necessity Waiting on Invention

While heat treaters have been diligently pumping out oil hardened steels, furnace builders and OEMs alike have been trying to find ways to move away from oil to quenchants that, primarily, reduce distortion, but also that are cleaner, require less processing, and present a safer working environment. Despite their efforts working with modified quenchants – including high pressure gas quenching (HPGQ) in vacuum furnaces – oil quenching has proven robust, maybe even stubborn.

Does that mean we are stuck with the integral quench furnace and its fire-breathing ways? Not necessarily. . . .

Figure 2. D-Type double chamber for batch work processing with conventional loading over the oil quench
Source: SECO/VACUUM Technologies

An Invention Waiting on Improvement

The concept of a vacuum oil quenching furnace is nothing new. When first developed, it was unique because it combined the advantages of vacuum heat treating with the ability to oil quench. But at the time, they were an unlikely couple that never really got along as well as the atmosphere furnace with an oil quench tank.

Vacuum oil quench furnaces were expensive, had large footprints, and were not particularly reliable. Plus, if case hardening was required, low pressure carburizing was not particularly attractive as it was still in its infancy, at least compared to gas carburizing. So, VOQ stayed in the shadows, fulfilling limited roles where the application warranted the extra complication of vacuum. In the meantime, the integral quench furnace became the workhorse of choice, churning out oil and case hardened parts for industries worldwide.

HPGQ Drives Improvement in Vacuum Furnace Technology

Despite the success of the integral quench furnace, VOQ remained present, stirring in the shadows. In the meantime, vacuum furnace technology advanced through the development of high pressure gas quenching. The design and construction of a vacuum furnace lent itself to this application well and introduced a host of advantages, such as found in Maciej Korecki’s “Case Study of CMe-T6810-25 High Volume Production”:
• Decreased distortion
• Elimination of intergranular oxidation (IGO)
• No decarburization

Vacuum Furnaces Move from Niche to Standard Issue

In addition, these design developments supported the opportunity to case harden parts through the use of low pressure carburizing (LPC). Coupled with quenching pressures up to 25 bar, the HPGQ-equipped vacuum furnace became a real option for the heat treater interested in through hardening that did not require:
• Special atmosphere generation equipment (atmosphere generator)
• Lengthy furnace-conditioning cycles to assure the correct gas carburizing conditions as is typically necessary in the batch IQ furnace
• Post-heat treating surface cleaning in the form of washing or oxidation removal

VOQ Begins to Follow Suit

Still, vacuum and HPGQ were limited in their ability to serve in the role of hardening some steels when considering common geometries. This meant that, for those steels, oil remained the go-to quenching solution. As a result, the VOQ furnace became the furnace of choice. It still required:
• Post-quench wash
• Aggressive oil circulation to minimize distortion
• Selection of the appropriate oil
• Careful fixture design
However, the advantages were too many to ignore. The fact that one could through harden steels like 8620 in a clean environment without the safety and cleanliness concerns inherent to integral quench furnaces was a huge advantage. And although furnace footprint remained a concern until the early 2000s, advancements in areas such as mixer design, vacuum pumps, and low vapor pressure quenching oils all contributed to decreasing the footprint and increasing the reliability of VOQ, making it an even more viable option. In more recent times, environmental concerns have also renewed attention to the VOQ furnace because of its vacuum capability. Advantages include:
• Electric heating – no natural gas consumption
• Inert gas atmosphere or vacuum environment – no atmosphere generator needed                                      • Zero CO2 emissions, even when case hardening using LPC

Figure 3. T-Type triple chamber for continuous batch work – oil quench or gas cooling/quenching with a separate chamber for preheating and semicontinuous operation
Source: SECO/VACUUM Technologies

Which Brings Us to Today

Vacuum oil quenching technology has progressed to overcome the challenges of yesteryear, and technological improvements have made it a flexible and configurable option for a heat treater’s current – and future – needs.

The VOQ is now available in configurations that provide both batch and semicontinuous options. This provides the opportunity to harden or case harden components with increased productivity and efficiency.

A common configuration offered is the two-chamber VOQ furnace as pictured in Figure 2. In this batch type configuration, common working zone sizes – such as 24″ x 24″ x 36″ or 36″ x 36″ x 48″ – are available with load capacities up to 2,650 lbs. A graphite-insulated hot zone provides the capability to achieve working temperatures up to 2400°F while providing the platform to case harden using LPC. This configuration also has the ability to conduct partial pressure heating using nitrogen. When quenching, the use of high-flow oil mixers promotes good oil mixing during quench to minimize distortion. This configuration can also cool in nitrogen above the oil in the quench tank, providing additional process flexibility.

In applications requiring higher productivity, a third preheating chamber can be added to the furnace system to provide the opportunity to preheat the furnace charge. The addition of the preheating chamber provides a semicontinuous operation as opposed to the batch operation provided by the two-chamber furnace. The result is a two times increase in throughput of the furnace system. Depending on the process requirements, production rates of up to 440 lb/hr are possible. The modern vacuum oil quench offers a versatile platform with a compact design capable of multiple processes and high production rates. The traditional two-chamber VOQ offers a batch platform capable of neutral and case hardening through the use of LPC. The three-chamber model provides similar options with the opportunity for high-capacity production through the addition of a preheating chamber with semicontinuous processing. Both demonstrate the advancements and the potential of this modern furnace as flexible, safe, and environmentally-friendly option in oil quenching.

Figure 4. An LPC process that yielded a net 1,322 lb (600 kg) load of gears with an effective case depth of 0.039 in (1 mm). This resulted in a throughput of 294 lb/hr (133 kg/hr). Slight adjustments to this process have rendered production of up to 440 lb/hr. (Source: Maciej Korecki, “Case Study of CMe-T6810-25”)
Source: SECO/VACUUM Technologies

References

Maciej Korecki, “Case Study of CMe-T6810-25 High Volume Production,” SECO/WARWICK S.A.
Maciej Korecki, “Case Study: Heat Treat Equipment Meets the Future Industry Today”
(Heat Treat Today, 2022), https://www.heattreattoday.com/equipment/heat-treating-equipment/vacuum-furnaces/vacuum-furnaces-technical-content/case-study-heat-treat-equipment-meets-the-future-industry-today/.
Don Marteeny and Maciej Korecki, “Triple Chamber Vacuum Furnace Systems – The
Low-Pressure Carburizing Workhorse,” SECO/WARWICK S.A. Presented at Heat Treat 2019
– ASM International.

About the Author: Don Marteeny has been vice president of Engineering for SECO/VACUUM Technologies for over five years. He is a licensed professional engineer and has been a leader at the company over the last several years filling project management and engineering leadership responsibilities. Don is a member of Heat Treat Today’s 40 Under 40 Class of 2021.

For more information:
Contact Don at Don.Marteeny@secowarwick.com

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Listen To Vacuum Heat Treat on the Radio Waves

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There’s always more to learn, and at Heat Treat Today, we strive to help you be well informed. Thanks to our Heat Treat Radio guests, we are happy to offer much more expertise on all things vacuum processing, including hardening, ion nitriding, and the stainless steel materials in vacuum furnaces.

This Technical Tuesday article was written by the Heat Treat Today Editorial Team for the November 2023 Vacuum Heat Treating print edition.

Heat Treat Radio #93: Why Ion Nitride? An Exploration with Gary Sharp

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Perhaps the most visual of all vacuum processes, ion nitriding is known for its unique purple glow, caused by nitrogen diffusing into the surface of the workpiece. Gary Sharp gives this glowing summary of ion nitriding, including the development of vacuum equipment to fit the process and special challenges like loading vacuum chambers and parts cleaning in this recent episode.

“[Ion nitriding is] a diffusion process. If you look at a piece of equipment, a hearth plate is a cathode in a DC circuit. The vessel wall is the anode, and the gas is your carrier.

“Through the transfer of energy, you bombard the part with ions and neutral atoms. They transfer their kinetic energy, and that is what actually heats up the parts. In the early years, that was the only way you could heat the parts. Later came more developed equipment.”

“Now, you have auxiliary heating in the walls, which adds some advantage but also a little more complexity in terms of keeping and maintaining a current density on the part adequate to diffuse into the metal itself. Sometimes you put it in a vessel, and you turn on the power supply. All the energy is coming from somewhere else, and you don’t actually diffuse or harden the part itself. It’s been solved, obviously, over the years.”

As Sharp further explains, some advantages of ion (or plasma) nitriding overlap with other forms of nitriding. But specific to this purple heat treatment under vacuum are its great masking abilities.

Heat Treat Radio #82: Gun Part Treatments, Turning Up the Heat with Steve Kowalski

When it comes to stainless steels for gun components, autonomy is the name of the game. Vacuum processing is “critical” in the gun part industry, says Steve Kowalski, president of Kowalski Heat Treating, for this reason of control over the part:

“With stainlesses and the various materials that we’re currently using, having high-pressure quench vacuums/high pressure quench allows for a significant amount of flexibility. We can finetune a recipe, or cycle, to achieve properties that the customer needs where it makes it repeatable.”

Rolls, slitter blades racked, and SS vavle seats for vacuum processing
Source: Kowalski Heat Treating

The means to reach the end of perfectly heat treated components are many, the critical step being defining the heat treat process itself. “The majority of what we process for the gun world (for the firearms world) would be either salt to salt rack austempering or marquenching, vacuum and actually plasma processing, whether it’s FNC or nitriding. We’re involved with those three areas in the gun world.” He later expands upon this list noting, “salt neutral hardening, salt hardening, and then marquenching or austempering, depending on the component.”

Heat Treat Radio #54: Metal Hardening 101 with Mark Hemsath, Part 2 of 3

“Hardening” is a broad thermal processing term that generally means increasing a material’s strength and toughness and minimizing distortion. Hardening can be done in a simple tip-up or bell furnace. So, which hardening processes require vacuum furnaces?

In addition to plasma nitriding as mentioned above, Mark Hemsath of NITREX sheds some light on carburizing as done in a vacuum furnace. He says, “Caburizing is the addition of carbon, right? So, the difference here is that when we talk low pressure . . . it’s done at a negative pressure, less so than atmosphere. We call this either low pressure carburizing or vacuum carburizing; it’s the same process. This takes place at pressures typically in the 1–15 torr range, which is about 1–20 millibar range of pressure. If you know one atmosphere is 760 torr, when we’re going down to 1–15 torr, we’re at pretty good vacuum. Just like with gas carburizing, the higher the temperature, the faster the process. What’s unique with vacuum equipment is that vacuum equipment is typically capable of going to higher temperatures which adds to the speed of carburizing.”

Unveiling the inner workings of a vacuum furnace, he adds, “Now, we didn’t discuss the design of gas carburizing furnaces that much, but typically they’re gas fired and they have radiant tubes. In the interior of the furnace, the higher temperature you go with the really nasty carburizing atmosphere, it reduces the life of those furnaces substantially, so the people that own the furnaces don’t want to go to high temperature. If you can go 100 degrees higher in temperature, like you can with the vacuum carburizing furnace, the process gets much faster. That means higher productivity.”

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