Hot Isostatic Pressing

Heat Treat Today publisher Doug Glenn discusses hot isostatic pressing with Cliff Orcutt of American Isostatic Presses, Inc. Learn about the revolution that is occurring in the heat treat industry and how it is being used across various manufacturing industries

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

The following transcript has been edited for your reading enjoyment.

Doug Glenn (DG):  First off, Cliff, I want to just welcome you to Heat Treat Radio.  Welcome!

Cliff Orcutt (CO):  Thank you.

DG:  If you don't mind, let's give our listeners just a brief background about you.

CO:  It's been 43 quick years in the industry.  I, actually, did start as a child.  My father was one of the original people at Battelle where it was patented in the '50s, so, I grew up under that.  Right out of school, I went to work for his company, after he and another gentleman left Battelle, Mike Conaway, and they formed Conaway Pressure Systems.  By the time I was 20, I had already installed 10 HIP units around the world and helped design and build the Mini Hipper.

I was involved in 1978 in moving the world's largest HIP unit from Battelle to Crucible Steel in Pittsburgh, which is now ATI.  Also, in 1979/80, we installed the very large system for Babcock and Wilcox at the Naval Nuclear Fuel Division in Lynchburg, VA.  Both of those units, 40 years later, are still running.

I'm also past president of the Advanced Materials Powder Association, part of MPIF, and I was also a director of their Isostatic Pressing Association.  I am currently the chairman of the International HIP Committee.  We put on the triennial HIP conference every 3 years.

DG:  Is that part of APMI?

CO:  It's actually its own group.  It was formed by all of the people in HIP around the world, in Europe and Japan and the United States back in, maybe, 1983 or so.

DG:  What's the name of the organization?

CO:  It's called the International HIP Committee.  It's kind of a loose organization which the only thing that we do is put on this conference and we bring in speakers from around the world and promote HIP technology, basically.  Our last one was in Sydney, Australia in 2017.  We were supposed to have one in October 2020 and now it's pushed until September of 2021.

DG:  Where will that be?

CO:  It's going to be in Columbus, Ohio because that was the original founding city.  Every other conference, we move to the United States, Europe or Japan.  So, it's coming back to the US.  I'm in charge of it.  We have some other good people on the board, including Mike Conaway, who was one of the original Battelle people.  Victor Samarov is on the board helping us with the meeting, programming and so forth.  People can visit www.hip2020.org to see information on that.

DG:  I got you a little distracted on that.  Keep going with your background.

CO:  Personally, in these 43 years, I've installed over 200 units, hands on.  I've flown about 5 million miles, I've been to 38 countries; you name it, I've been there, good ones and bad ones.  In my early years, when my father started this company, they pulled about 6 people out of Battelle and they were, basically, my teachers.  So, instead of going to educational school, I went to HIP school.  We had some of the top people:  Roger Pinney, Hugh Hanes, Don Woesner, Gary Felton and another gentleman, Bob Tavnner, all came out of there.

In 1979, my father passed away, and his company then sold to ASEA who then became ABB who then became ABB Flow and then they became Quintus now.  That's how they have a location in Columbus, as well.

A couple of people, including Bob Tavnner, left and formed International Pressure Service.  That was in 1983.  They hired me as operations manager, and we grew to be a force to be reckoned with and the Japanese then bought us.  At that time, Rajendra Persaud, or Reggie we call him, left and formed AIP (American Isostatic Presses) and I said, “Hey, Reggie, let's have a two person company again rather than two one-person companies.”  That was 1992 and so, 28 years later, now we're a force to be reckoned with again.

DG:  Tell us a little about AIP.

CO:  American Isostatic Presses, when the Japanese bought us, we had a lot of technology and a lot of good people.  Then they hired a new CEO and he decided he didn't want to continue building HIP units, he wanted to do something else.  So, Reggie formed AIP and I joined him and we pulled 5 other people back from ITS.  We sold our first big job in 1994 to Horus in Singapore, a multimillion dollar job, and took off from there and haven't looked back.  We started on a shoestring, no venture capitalists, no dollars, and now we have 4 buildings and locations around the globe.

"We're just a high tech blacksmith, that's all it is.  Instead of hitting something with a hammer, we're using gas pressure to squeeze on it."

DG:  How many units do you think you guys have installed since 1994?

CO:  As AIP, around 150.  It's snowballing.  In the last 5 years, we've sold 5 big units.  Up until that time we were mainly mid and small.  We had orders for some big ones but, unfortunately, we couldn't get export licenses for them.  The technology that grew out of Battelle was based on nuclear fuel rods for the submarines.  Admiral Rickover wanted to extend the life of the sub, so it was protected for quite some time.  And then they also had missile nose cone technologies it was used for and that's still what they're protecting it for is missile nose cones.

We had some orders in the late '90s early 2000 through China for large equipment and we were denied.  Then we were denied in India, so we kind of just got stuck with the smaller to mid-size units.  Here recently, it's starting to expand.  Things are loosening up a little bit.

DG:  AIP today is selling not only in North America, obviously, but you're pretty much selling around the world, anywhere where it is legal to sell, you'll do it.

CO:  Yes, if we can get an export license, we will put it in.  Some of the rules have relaxed a little bit, and, with some countries, we're more friendly with them now.

DG: I think a lot of our listeners are probably not going to be as familiar with HIPing, hot isostatic pressing, as other more common “heat treat operations” like carburizing, hardening, annealing and that type of thing.  Take us back, class 101:  What is HIPing?

CO:  We're just a high tech blacksmith, that's all it is.  Instead of hitting something with a hammer, we're using gas pressure to squeeze on it.  We heat it up hot, we put pressure on it, and we're basically densifying it, making it more dense, and getting rid of imperfections in the metal.

A lot of what's done is castings.  When you have a casting, the metal is hot, so it's expanded.  When it cools, it cools from the outside in, so it freezes on the outside first and then the center starts to shrink.  It creates internal porosity.  Most of that porosity is thermal shrinking which is a void.  So, you put it back in our heat treatment, apply pressure to it and you get rid of the voids that are left.  You make the casting dense and better grain structure and more homogenous.  It increases fatigue in property strength.  That's the number one use of it right now.

Second is probably powder metallurgy where you take powder metals and you can blend powders and you can start with different grain sizes and different materials.  You put them in a container because the gas would go through the container if you didn't have something around it.  So, you squeeze on the container and it densifies whatever is inside of it and you make a solid part.  For example, a lot of powder metallurgy billets which are then used for extruding into other products or rolls and different things.  We do a lot of pump bodies and valves for deep sea work, extruder barrels, you can bond things; there are a whole lot of applications.

DG:  The two things I understand with HIPing are high temperature and high pressure.  Give us a sense of high temperature.  What does that mean?  Is it hotter than a typical heat treat operation?  And. how about the pressures?  Give us a sense of what the pressures are looking like.

CO:  A lot of people are familiar with sintering.  That's where you just take the metal up, you sinter it and the grains merge together by melding and attractive forces.  What we're doing is: we're not taking it up to those high temperatures to where the part actually is molten or melting, we're taking them up below that and applying pressure.  Because of the pressure, we're basically pressurize sintering; we're adding force to make it sinter faster or better or at lower temperatures.

Usually, it's about 150 C degree less than sintering temperature.  Again, it depends on the process of what we're trying to do with it.  Typically, most parts are done around 15,000, some parts 30,000.  Here, at AIP, we actually have test units up to 60,000 PSI and we've actually built 100,000 PSI HIP units.  You're above the yield strength of some of the metals you're using.  Most of the majority, again, in like castings, titaniums around 970, steels around 1225, but we go up to 2200 C for some things, even higher for like half-in carbide with people pushing it to 2300.  It's pretty hot, a lot of pressure.  Unfortunately, high temperature and high pressure costs money.  You want to use the lowest pressure and the lowest temperature you can get by with, but sometimes you can't.

DG:  It's harder, I would imagine.  The way I've always heard it said is that the hotter it is, the more difficult it is to keep, let's say, that cylinder container that you're talking about.  If it becomes hotter, it's harder to keep it together.  I would guess you're right, when you've got higher temperatures, things tend to blow apart easier?

CO:  Not so much.  The temperature is contained in the middle of the pressure vessel, so you've got plenty of insulation around it and you keep your container cool.  The goal there, in a HIP unit, because it's the expensive piece of item, you want maximize your work zone, that's where you have to have good engineering to make sure you do keep the container cool.

DG:  Are most of those units water cooled jackets, or are they cold wall?

CO:  They're almost all hot wall, but some of them are cooled internally and some of them are cooled externally.  You still have loss to the metal, whether it's internal or external cooled, but internal gives you faster cooling than the external.

The big advantage of HIPing is, like with some materials like titanium, you can eliminate a lot of machining.  Making chip that you can't really reuse real easy makes a lot of economic sense.  Titanium is a very high melting temperature, so you can't take those chips and melt them cheaply.  Aluminum, you can.  A lot of aluminum, people can't afford to HIP it because you can just recast it.

HIP is an expense process.  The equipment is expense.  It uses argon gas.  Swinging a hammer is cheap, but using gas pressure, it's so compressible, that you have to put a lot in.  You can reclaim some, but the cost is still high.  You're talking medical, aerospace and military, basically.  Forty years ago, I thought every car would have HIP pistons.  It's just not going to happen.  They can't afford it.  I do see Edelbrock and Trickflow both have HIPed aluminum race heads, though.  If you get into where you have the economy of doing something like that, you can apply it.  You're definitely going to get a better product, it's just price versus performance.

Watch an "oldie but goodie" on what HIP is.

DG:  As far as why people want to do the HIPing, I guess, primarily, it's an elimination of, let's say, defects or inclusions or whatever, either cast parts or powder metal parts, you're increasing fatigue strength, and things of that sort.

Are there any other major reasons why people want to HIP?

CO:  Well, there are some things you can't make other ways.  In other words, it's like water and oil, you can't mix them very well and some metals you can't melt them and just make a molten bucket and pour it.  In HIP, since you're starting with powders that are solid, you can blend things like graphite powder and steel.  You couldn't blend them very well in a molten state, but in here, you can.  And, you can squeeze it to solid, you can get interlocking and bonding and diffusion bonding materials that you couldn't otherwise.  So, you can make things you couldn't make any other way.

Also, you can eliminate machining.  For instance, you're making a titanium fitting that has a lot of holes on the inside, it might even be curved and really hard to drill, but you can lay it up and do powder metallurgy around it and make shapes that you couldn't make otherwise.  A lot of parts are pressed and sintered for years, for instance, for transmissions.  Something like that is real easy because it's a small disc and it's not very long.  But, if you're trying to make a real long part that is a strange shape, you can't just press and sinter it.  You can do it from HIPing.  You can do big shapes that you couldn't get enough force on or you can't fit into a press dye.  You can do big shapes that you couldn't get enough force on or you can't fit into a press dye.  It opens up a lot of options.  A missile nose cone, for instance.  There is just almost no way to press and sinter a cone, but with HIPing you can make that shape and you can make it very uniform.  There's really no other way to do it.

DG:  I think that is one of the benefits of HIPing, from what I understand, it is absolutely equal pressure on all parts when you increase the pressure.  It's not like you're only pushing on one part, like with a forge press, or something like that – equal pressure all round.

CO:  Yes.  And it gives you uniform density throughout the part, which is very difficult.

DG:  HIPing is primarily used on castings, powder metal and things of that sort, helps us get a very clean part, if you will, to eliminate inclusions, and minimize the porosity.

You may have mentioned this before, but the actual history of HIPing.  It started at Battelle?

CO:  It started at Battelle [Memorial Institute], I think in '55 or '56.  Again, for the nuclear fuel rods for cladding of the fuel rod.  Four people were involved in the patent, two of them, Ed Hodge and Stan Paprocki, "the two others on the patent were Henry Saller and Russell Dayton" I worked for both of them over my years.  It grew out of Battelle and then in 1975 is when my father and Mike Conaway left and formed Conaway Pressure Systems.  That was kind of like the beginning of the commercialization of it.  There were some other companies, like Autoclave Engineers, that were building high pressure equipment, but they weren't really offering packaged HIP units.  Conaway Pressure, CPSI we called it, was really the origination of commercial HIPs as we know it.

DG:  You hit on this a little bit, but I want to make sure that we're clear on it.  You mentioned the industries that are using it, but let's just review that real quickly, and maybe if you can give any example of parts.  You said, they've got to be higher value parts because the process is expensive, so we're looking at aerospace, medical and that type of thing.  What primarily, at least in those two industries, and other industries if you want to list, are the parts being run?

We’re seeing a lot of application now in ceramics. We see pump plungers and ceramic bearings. Here, at AIP, we do a lot of military work for armor, boron carbides, spinell (21:03), things that are really hard, ceramics. . . You want them perfect because if they have a defect in it, that’s a starting point for a crack. A lot of brakes for jets and fighter jets.

CO:  A lot of extruder barrels.  What happens is you can use a solid steel chunk of metal for the barrel portion but then you can HIP or diffusion-bond powders on the inside of that barrel that might be very expensive.  If you're doing something like a crane or something where the teeth are outside, you can weld on.  A lot of times they'll weld on hard brittle materials that help you dig things with a digger.  But on an extruder barrel, it's on the inside, it's internal; it's very hard to coat down on the inside.  So, we can actually bond those powders to the inside of extruder barrels.

Another big application is sputtering targets.  I don't know if you're familiar with sputtering targets, but they're basically sacrificial material that you plate onto other materials.  The target is just something that is being hit with an electron beam inside a vacuum furnace.  It creates a vapor and by charging the different particles you can attract  them and plate things out.  All of your mirrored windows, all of your hard drives, all of your CDs and DVDs, when you see that mirrored finish on there, that is a sputtered coating and those coatings come from these things we call targets.  What happens is, if say, you're doing a chromium target, at the end,  if you try to molten cast it, if you had a bath or a melt of chromium, it would get oxides in it and be terrible.  But, you can make very pure powders.  That's one of the good things about HIPing is they can make very pure powders by blowing argon through a stream and it makes nice pure powder.  Then, we can put it in and squeeze it into a solid billet and make a target which then can be evaporated in the vacuum chamber for coating.

We're seeing a lot of application now in ceramics.  We see pump plungers and ceramic bearings.  Here, at AIP, we do a lot of military work for armor, boron carbides, spinell (21:03), things that are really hard, ceramics. . . You want them perfect because if they have a defect in it, that's a starting point for a crack. A lot of brakes for jets and fighter jets.

We have a process inside the HIP that we call carbon-carbon impregnation.  We take pressure and we push the carbon into the 3D woven graphite fibers and make brakes and nose cones.  Other materials like beryllium, it's very hard to make beryllium and machine it because it's kind of dangerous, and so forth.  Again, they take powders and the HIP the beryllium to make things like space mirrors and other jet parts.

Now, we've got into more things like teeth and braces are being done with ceramics- new transparent braces made out of aluminum and different materials, zirconia caps for your teeth.  Again, if you don't HIP them and they've got a defect in it, it will be like a plate when you drop it.  But, if you get rid of that defect, now you've got something harder than steel.  On the other end we're doing jewelry such as gold and platinum rings.  The benefit there is you don't have porosity.  If you have porosity, it's like trying to sand a sponge and you can never find a nice perfect surface.  But if you've got rid of that and the sponge is now hard, then you can polish it and you're not taking off any material.

It hasn't really happened too much, but we're seeing rumblings on phone cases.  A lot of those have been metal in the past, but now they want to do the magnetic charging and it doesn't work real well.

DG:  It's got to be glass of some sort, right?

CO:  Yes. We're competing with Gorilla Glass.  Some companies are looking at transferring that to zirconia.  The iPhone watch, or iWatch, they were making it in zirconia, and that's one of the applications and things like that.  Ceramic rings, ceramic knives, ceramic scissors – they're all being HIPed.

On the diffusion front, like the vacuum plates for the fusion reactor, like ITER, they can bond copper to tungsten and different things.  You couldn't really weld them, because if you try to weld tungsten, it gets real brittle and cracks, but you can diffusion bond materials and you can do things you couldn't do otherwise.

DG:  Those are great examples, and I think that gives folks enough.  Are there any other examples that jump to your mind that you think people ought to know about, or is that it?

CO:  The big one right now is 3-D printing.  There is a lot of interest in 3-D body parts, titanium, stents, spines, implants for teeth and screws.  Just about anything you can put in 3-D, they're trying to print.  The problem with 3-D is, it's not perfect yet.  Maybe in 10 years it will be perfect, but they're making imperfect parts when they print them.  If you put them in the HIP and squeeze on it, not you've got a pretty much perfect dense part that's bonded better, stronger, improved properties.

It also allows you to print faster, so maybe you'll want to print an imperfect part, but you can just print twice as fast, so you increase the range between the particle and speed up your process.  Again, price versus performance.  You look at what the benefits of the two ways are.

DG:  I've got a question.  In heat treating, a lot of times after heating, you have to worry about dimensional change of the part, right?  So, I'm thinking to myself, you've got a cast part with some innate porosity and you put it in a HIPing unit.  Do you have to compensate, or do you have to be careful about dimensional change, most notably, I would think, with pressure shrinkage of the part?

CO:  Very little because it's isostatic and we're talking about micro macro small porosity.  If you had a 1 inch hole in the center and you were squeezing that out, you might give it up, but microscopic particle size is really not that much.  Now, in the powder metallurgy, we say it's isostatic but then you do have some of the stresses in the container that you put around it.  You might see some distortion at the corners where you welded a container, and so forth.  But, there's good software out there, there's good programming and things and a lot of empirical data.  People can pretty much design to shape within a couple millimeters.

DG:  You mentioned this earlier, but the gas that's used is predominantly argon, because it's a heavy gas?

CO:  The reason we use argon is the furnaces we use can't run in air or oxygen.  We have a choice of nitrogen or argon, the two commercial grade gases.  Nitrogen also embrittles materials like molybdenum.  It tears up our furnaces, so argon is the preferred choice.  Also, it has poor thermal conductivity which is good for the insulating portion of the HIP unit and when you get it dense enough then it does conduct good enough that it works for the part.  It's the all around cleanest, best gas but it's an inexpensive gas.  We do use nitrogen on some things.  A lot of ceramics like silicon nitride we'll use nitrogen, for different reasons.

One of the biggest issues right now is we see a lot of interest in oxide ceramics.  I've got many customers that want us to build a real high temperature oxygen furnace and we're real close to issuing that.  What it will allow is to actually sinter in the HIP unit at high temperatures under partial oxygen which hasn't been done yet.

DG:  Let's change gears just a little bit.  You actually have two sister companies.  I want to ask you two questions and you can incorporate information about those sister companies with this:  One, why would a company want to outsource a HIPing process?  And, two, on the flip side of that, why would a company want to purchase their own HIPing equipment and do it in-house?  Maybe you can address both of those, because you've got experience on both sides, based on your sister companies.

CO:  The outsourcing is really easy.  If you've only got one part to HIP, you're not going to buy a HIPing unit.  It's quantity versus can you support the operation of the HIP unit.  And, you've got to do it profitably.  You've got to do everything profitably or you're not going to do anything.  You've got to look at the capital equipment cost and the space.  Maybe you don't have space in your building or you don't want to build a new building, or, maybe you just don't have the people that have the knowledge in HIPing and you don't want to hire and train a maintenance crew, and so forth.  Even some big companies like Pratt &Whitney and Wyam-Gordon both owned massive HIP units at one time and they decided it was cheaper to sell the HIP unit to Bodycote and then outsource it.

Sometimes economics may play in there, but sometimes maybe you want to have in-house sourcing.  Maybe your part is so heavy, you can't afford to ship it.  Then, you look at that and say you might want to have your own HIP for that reason, or you've got so many parts, you just can't afford to box them all, ship them out and bring them back.  So, there are reasons why you'd want to own your own HIP unit.

DG:  You've got sister companies that do the service, right?  AIP, American Isostatic Presses, the company that you're with specifically, they build the units.  But you've got sister company that actually does the service.  Tell us about them a little bit.

CO:  When we started out, we were just going to build HIP units and we were selling to a lot of the toll companies and we still do.  But, around 2004, after the economic downturn of 2001, we decided we would get into building our own pressure vessels.  We hired an engineer, Dan Taylor from Hydropack, and started building pressure vessels because we thought we could do it better.  Then we were looking at toll.  A lot of people would come to use and say they were not happy with turnaround or other things and they asked if we could help them toll HIP?  We kind of got drug into it.  We didn't, again, want to step on our customer's toes, so we came out with a different name and sort of hid behind that a little bit and didn't really even market it for a long time.  But then again we kept getting dragged in, so we opened another plant and now, this last year, we opened another one.  I've never seen a toll HIP company go out of business yet or lose money.  Equipment building is up and down, you're riding the waves.  It helped us flatten the curve a little bit.  It flattened out the cash flow curve and it helped us a lot.  Our competitors weren't doing it.  They still aren't really doing it like we're doing it.  The original name was Isostatic Pressing Services (IPS), then when we did our plant in Oregon, we called it ITS, Isostatic Toll Services.  The family wanted to have different names and different people involved and there are different investors.  It's AIP, basically, but there are other family members in the Persaud family.  In Spain, the big one we opened last year, it kept the ITS name, but there are five players in that one, so we're one of the players.

DG:  So, the sister companies have Toll Services, I know one in Oregon.  And one in Ohio?

CO:  The other is in Mississippi and then one in Spain.  The Ohio one is under the AIP name.  Basically, what we do in Ohio is we do more research.  We, again, are expanding here in Columbus.  We are getting ready to build again and we'll start heading a little more into the production toll.  We've got a couple customers that are, again, pulling us that way.  But, right now, Columbus has 5 HIP units, up to abut 500 mm in diameter.  Most of it is high temperature.  In Columbus, we concentrate on 2000 C.  All of our other plants are doing production work which is medical implants and turbine type parts and those are all 1225 C roughly.

DG:  Let's talk about some of the more latest advances, some of the newer things that are coming onto the scene.  You mentioned one, I know, and that was the ceramic oxides.  Let's talk about that a little bit more, and also, are there any other advances in the HIPing world that we should know about.

CO:  I've been in it from almost day one, and it hasn't changed much.  If you look at HIP from 40 years ago and today, they'd look the same.  We still use the same valves and fittings.  The big thing that has changed is computer control.  AIP was one of the very first, I won't say the first because, again, back at Battelle in 1973, they had a Foxboro PDP that was in the whole room and had tape reels in it.  I remember seeing it run a HIP unit, you'd type in STOP and START.  It was like a movie.

Around '93 or '94, AIP branched into computer control pretty hard and we've kind of  led since then.  It allows us to do a lot of things, number one is that we can run it remotely.  So, in Mississippi, we actually run our plant from Columbus.  They load it and we take it over here.  Our guys here in Columbus, they run our units all night by staying at home and watching them.  Computers really help us there.  As for service, we were able to get on the computer and look at a piece of gear in Singapore and fix it.  That's the thing that really helped us.

"Where we're advancing things is in furnace technology for high temperatures, getting these furnaces to last longer, making them more reliable. . . We're trying to hit the everyday guy and make him profitable, get parts in and parts out."

Where we're advancing things is in furnace technology for high temperatures, getting these furnaces to last longer, making them more reliable.  That's kind of one of the keys because, again, with costs and the economics of HIP is you want not to have to be repairing it and replacing things all the time.  That's what we concentrate on.  We don't try to push the edge.  I think some of our competitors really try to push the edge and do things that may or may not be beneficial or even needed, but they're just trying to push the edge of things.  We're not.  We're trying to hit the everyday guy and make him profitable, get parts in and parts out.

As far as the oxygen, that's because ceramics has been coming for a long time and it's still coming.  It's just never really taken off yet, but sooner or later it has to because they're higher temperature, stronger materials in steels, it's just we are competing against forgings and we re competing against casting companies.  That's kind of the whole thing with all the HIP companies.  There are basically only four main players in the world.  We are all kind of small.  We all kind of try to work together as much as we can and we all make good equipment to try to advance HIPing technology.  More than beating up on each other, we try to beat up on the forging companies and the casting companies.  We want to take their business.

In the research here, a lot of what we're doing is trying to work on the higher temperatures and higher pressures.  If you can go to higher pressure, you can drop the temperature which then minimizes grain growth.  In many materials, that improves either clarity of the material, if it's a transparent ceramic, or it can improve the strength of a steel because you have better interlocking between small particles.  We're trying to do a lot more in high pressure, high temperature than some of the other companies.  A lot of the companies are just in the metals only; they really focus on that.  We're doing some really odd things here.  We do stuff that nobody else wants to fool with.

DG:  And you have fun while you do it!  I'm curious, just from my own purposes.  I envision these things as kind of like bell furnaces, a cylinder.  Is that true?  And, how big, on average, is a HIP unit?  What's the work zone dimensions, let's say?

CO:  They start with our smallest one which is about the size of a desk and it has a work zone of about 3 inches x 4 inches.  We can build a little bit smaller, but economy-wise, we just built that one small model and that is the smallest that anyone uses.  It's the size you need for a tensile bar.  Just about every university and lab has an AIP small unit.  Then, they can go up to massive units.  The large one in Japan that Quintus built is 82 inch hot zone.  That's a big diameter.  They're talking about a 100 inch or 110 inch hot zone.

DG:  That's diameter.  How tall was it?

CO:  3 meters.  Some people are looking at 4 meters or even longer.  I've been told that the Army said if you can put a whole tank in one, they'd do it.  One of the drivers there is turbine blades.  As the blades get bigger, like on jet engines, your turbo fan is the outer blades and so forth, those big shrouds as they get bigger, the gas economy gets better, so they would like to build massive engines and they would like some of those parts HIPed.  They want really big HIP units.   Another one is in nuclear reactors for small modular nuclear power.  They'd like to replace some forgings and if they could do it with powder metallurgy lids, and so forth, and those need a 3mm diameter HIP unit.  The majority of the work is in the 1 meter range.

For more information: isostaticpressingservices.com or aiphip.com/links

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