We hear the term “preventative maintenance” often used in the industry. Setting up procedures in advance to avoid unplanned downtime and other avoidable costs is certainly a hot topic. But this Heat Treat Today Best of the Web feature highlights a maintenance strategy that has become increasingly popular in creating better industrial efficiency: predictive maintenance. Read today’s feature article to learn about what predictive maintenance is, how it is implemented in a vacuum furnace system, and how this strategy saves you money.
An excerpt: “Predictive maintenance (PdM) evaluates the condition of equipment by performing periodic or on-line asset condition monitoring. Most PdM is performed while vacuum furnace is operating normally to minimize disruption of everyday operations. This maintenance strategy leverages the principles of statistical process control.”
The Furnaces North America 2020 was a virtual session, giving presenters the opportunity to create pre-recorded videos as a tool for future learning. The information for today's Heat Treat TodayTechnical Tuesday is pulled from a session delivered by Matt Clinite, customer service (aftermarket) sales manager at Ipsen USA.
As the sales manager of aftermarket sales at Ipsen USA, Clinite is familiar with what makes and breaks the lifetime of a vacuum furnace. In his presentation titled, "Vacuum Furnace Best Practices for Greater Reliability and Efficiency," Clinite presents a technical overview of the "five fundamental steps to keep your vacuum furnace running at peak performance."
An excerpt: Four of the five principles to assess your vacuum furnace's present condition right now are:
Start with the Hot Zone
Review Your Temperature Monitoring Systems
Assess Your Water Cooling System
Check Your Pumping System
And..[watch the video!]
Additionally, Clinite guarantees that viewers will learn three things: identify and correct common furnace problems; establish a maintenance plan; and improve reliability, efficiency, and overall capability of your furnace. If anything else, walking through how to build a preventative maintenance checklist will be a helpful review for any heat treater!
What is debinding in metal additive manufacturing (AM)? How do you debind after 3D printing? How do you avoid contamination during metal debinding? Heat Treat Today’s Technical Tuesday article features this Best of the Web piece to answer your questions.
There are several changes that have made new technologies of AM and 3D printing increasingly implemented in the heat treating process. Some of these reasons include: falling costs of 3D printers; increasing geometric abilities; constant rate of the costs of production; and a “drastic reduction” in process waste. Read on to learn how to properly “debind” as you implement these new technologies in the heat treatment process.
An excerpt: “The working temperatures in the debinding phase are in the range between 70 °C (158 °F) and the 450 °C (842 °F), corresponding to the melting temperatures of the various organic compounds.”
Jim Grann, Technical Director, Ipsen (photo source: www.ipsenharold.com)
We all like to make savvy commercial decisions, in fact, Heat Treat Today’s 101 Heat Treat Tips on page 20 of this digital magazine is a great example of tips that can save you time and money. But will it pay off to use your conventional vacuum furnace for aluminum brazing?
Questions involving safety, effectiveness, and quality might come to mind with this proposal. Before implementing such a strategy, head over to Heat Treat Today’s best of the web Technical Tuesday article by Jim Grann, technical director at Ipsen. He tackles the components of aluminum brazing versus the capabilities of conventional vacuum furnace as well as detailing some of risks that can happen if you do try to use your conventional vacuum furnace for aluminum brazing.
An excerpt: “By nature, vapor pressure aids in the depletion of magnesium and parent aluminum alloys in high vacuum, depositing magnesium onto the hot zone and into the shielding… Proper vacuum aluminum brazing requires special components that standard vacuum furnaces generally do not have, including…”
Heat TreatTV pulls the best heat treat videos from the web for your viewing, and today Heat Treat TV highlights Solar Atmospheres.
As a commercial heat treater, Solar Atmospheres is dedicated to providing vacuum heat treating and brazing services of the highest possible quality and meeting the expectations of their customers. They seek to educate their customers and will design a heat treating process that fits their needs.
This video demonstrates what a commercial heat treater considers when processing parts, including explaining why a heat treater chooses some methods over others. Topics mentioned in the presentation are brazing, carburizing, and nitriding as well as post-heat treat processing, vacuum brazing, vacuum carburizing, and vacuum gas nitriding.
Click here for more information on Solar Atmospheres.
If you have a video you’d like included on Heat TreatTV, please send an email to editor@HeatTreatToday.com and include a link to the video.
Discover how to keep your furnace in prime working order as Fred Hamizadeh, director of Global Manufacturing Services- Heat Treat & Facilities Equipment, of American Axle & Manufacturing and keynote speaker at Furnaces North America 2020 (Virtual) Trade Show, outlines the essential attributes of effective maintenance practices for industrial heat treating equipment.
This article will be featured in Heat Treat Today’s upcoming FNA Trade Show issue in early September.
Fred Hamizadeh, Director of Global Manufacturing Services- Heat Treat & Facilities Equipment, American Axle & Manufacturing
I recall great advice from my first boss, Bob Williams, of Williams Industrial Service: He said to me early on that if the maintenance people are happy with your equipment, you’ve designed a good furnace. Combining many years of my OEM furnace manufacturing experience with my current position allows for a perspective that is useful to both American Axle & Manufacturing (AAM) and our OEM suppliers.
American Axle & Manufacturing can trace its history to the early 20th century and was comprised of the five General Motors plants, purchased by an investment team led by our co-founder, Richard E. Dauch, in 1994. Heat treating has been a core competency of the AAM manufacturing system since the inception of the company. AAM uses conventional gas carburizing and tempering as well as various induction processes in the manufacturing of all drive-train components. These components include: case hardening of gears and pinions; induction hardening of shafts, CV joint and balance shafts; and sintering of powder metal. Our metal-forming product business unit uses induction heating to forge and manufacture a large variety of automotive components. As one of the largest captive global heat treaters, AAM’s carburizing equipment varies in size and style, from batch to single and multirow pushers. Induction equipment cells also vary from single spindle to multi spindle, fully automated hardening and tempering lines.
“While we remain open to all new developments and advances in technology, it does not provide suppliers with an open checkbook. We must maintain a balance between high technology, reasonable CPU, component performance improvement, and reliability. “
(Photo source: American Axle and Manufacturing)
An integral part of AAM’s quality process is the maintenance and reliability of production equipment including the heat treat equipment. To remain current with latest CQI-9 requirements, all maintenance intervals are scheduled, followed, and monitored by the company leadership. All AAM facilities have an advanced maintenance team that performs most of the day-to-day requirements and responds to all emergency cases.
Maintenance requirements must be considered early on during equipment selection, procurement, design, and manufacturing. AAM has specifications that heat treat manufacturers must follow to allow safe and fast maintenance to occur regularly without requiring equipment to be removed from production. As a minimum, sufficient access points within the equipment are essential. A preferred location would be to have access from the plant floor; otherwise, safe platforms must be provided. All hazards such as heat, electricity, and stored energy must be eliminated or locked out. A detailed LockOut TagOut (LOTO) system diagram allows maintenance to be performed safely. Use of our recommended parts list ensures that we have common components for speedy repairs within our stores.
(Photo source: American Axle and Manufacturing)
Today, we look for equipment that has the following features to allow extended mean time between failures (MTBF), provided regular scheduled maintenance is completed:
Equipment built to AAM’s specifications for heat treat equipment. These specifications are designed based on our needs and best practices as well as supplier capabilities and regional presence.
Use of common components within company provided parts list
Use of domestically available and reliable material and components for equipment built in various regions of the world for ease of replacement. Otherwise, the use of U.S. or European brands with global presence is preferred.
Use of standard equipment design to allow common spare parts that can be shared between plants. This standard design will also provide equipment interchangeability and allow maximized equipment utilization based on plant loading.
Use of common control equipment and sensors. We utilize two brands of process controls. Our electrical systems use AAM Controls Architecture specifications that allow all plant control engineers the ability to troubleshoot, repair, and place equipment back into production rapidly.
Use of highest-grade cast or wrought nickel-chromium grade components to insure long MTBF. This is one area that must be observed closely during the bidding process.
Use of brick lining for all carburizing zones. This eliminates the carbon burnout issues associated with ceramic fiber lining.
Use of reliable, dependable, and global suppliers. Our need to maintain interchangeability and versatility to maintain high utilization rates require suppliers to have presence in North and South America, Europe, and Asia. Same is true for component suppliers. Rapid response to issues is critical for our operations and most of our suppliers have met this requirement.
Enforcing a maintenance schedule that allows for maximized production while allowing time for burnouts and maintenance. Maintenance and burnout schedules are established a year in advance. These schedules are communicated and balanced with production requirements. This period is not only required for performing needed maintenance but should be used to plan the next maintenance activities.
Detailed LOTO tags to pinpoint all sources of energy that need to be locked out to perform safe maintenance.
Detailed inspection of equipment for safety, maintenance, and function prior to shipment from supplier.
Provide training for engineers, technicians, and operators in safety operation and maintenance of the equipment by the manufacturer.
For large and complex equipment, monitor force and cycle time historically as early indicators of maintenance requirement.
While there are some new developments and advancements in the maintainability of equipment using the latest digital technologies such as Mobile Maintenance Assistance by Aichelin, more development needs to occur to allow integrated maintenance, record keeping, spare parts ordering, and monitoring. Digital archives of system drawings and manuals must be available for a maintenance technician at point of use. Additionally, video recordings of training sessions can be maintained at the equipment for training new associates.
(Photo source: American Axle and Manufacturing)
The future of heat treat will include more advances in induction processing, austempering, and further development of liquid quench capable LPC equipment. Over the last 30 years, many new processes have been introduced into the market but were unable to justify eliminating conventional gas carburizing and induction hardening. While we remain open to all new developments and advances in technology, it does not provide suppliers with an open checkbook. We must maintain a balance between high technology, reasonable CPU, component performance improvement, and reliability.
About the Author:
Fred Hamizadeh, a mechanical engineer and 32-year veteran of the heat treat industry, is the director of Global Manufacturing Services-Heat Treat & Facilities Equipment, at American Axle & Manufacturing. The majority of his experience has been focused on the OEM side of heat treating with Surface Combustion and Williams Industrial. For the last 14 years, Fred has worked on the consumer side of heat treating with AAM.
For more information, contact Fred at Fred.Hamizadeh@aam.com
As society begins to slowly reopen in the wake of the COVID-19 pandemic, equipment that has been sitting idle will need to be brought back online.
In this Heat Treat Today Original Content feature, Abbott Furnace gives us a few important considerations to ensure a successful return to operation.
1) Reference the manufacturer supplied manual for specific information regarding the re-starting of the equipment.
2) Be sure that water is flowing to all of the cooling chambers of the furnace.
3) Check that the belt is on and moving smoothly through the furnace. Watch for jerking or jumping of the belt that would indicate an issue with the drive or pathway through the furnace.
4) Enable the ramp mode in your controls to limit the heating rate of each zone to 55C (100F) per hour or less. If the furnace does not have a ramp mode, be sure to manually adjust the set-points of each zone so as not to exceed the suggested ramp rate.
5) Once the furnace reaches 150C (300F) , purge the furnace with nitrogen and allow the nitrogen to flow as the furnace continues to heat up.
6) When the zones of the high heat section of the furnace are above 760C (1400F), combustibles may be introduced and the furnace can continue to be ramped to the final processing set-points, once the pilots are ignited.
7) Allow the furnace atmosphere to re-condition the furnace, clean the belt, and stabilize.
Loading scrap metal that is free of oils, grease, and rust will help the furnace to “clean-up” and stabilize.
Reactive maintenance is expensive and usually requires downtime, holding up production. In contrast, preventivemaintenance keeps these failures from occurring, which results in cost savings for manufacturers. Research shows that preventive maintenance can produce a 12 to 18 percent cost savings as opposed to other reactive maintenance programs.
In this Heat Treat Today Best of the Web feature, Lindbergh/MPH offers important preventative maintenance tips for heat treat furnaces.
Preventive maintenance is a list of regularly performed procedures that decreases the likelihood of a piece of equipment failing. It is performed by operators while the machine is in good working order. Regular maintenance also keeps equipment running at top performance and extends its life.
5 Preventive Maintenance Items for your Heat Treat Furnace
Heat treat furnaces are used in many manufacturing processes, including tempering, preheating, quenching, stress relieving, annealing, and more. Many factors, including high temperatures, place considerable wear and tear on the furnace components. Eventually this can cause bearings to flake, leaks to develop, and other problems to come up. Small issues can lead to mechanical failures over time that in turn lead to reactive maintenance.
Some common preventative maintenance services for heat treat furnaces include:
Tuning Combustion Systems – Component wear, high temperatures, and other factors lead to burner settings drifting over time. This ultimately affects efficiency, fuel usage, emissions, and product quality. Tuning the combustion system maintains optimal performance and efficiency rates, limits excess emissions, and improves product quality.
Bearing Inspections – Functional bearings are crucial to any machine, but even properly installed and operated bearings wear down over the course of time. The contact surfaces of bearings repeatedly withstand compressive loads, which eventually causes the surfaces to flake. Inadequate lubricant, improper lubricant type, breakage, wear, corrosion, and other factors can lead to bearing failure. A broken or seized bearing can stop equipment, potentially bringing the entire production line to a halt.
Leak Testing – Even the smallest leak can reduce production performance and possibly result in system failure. Preventive maintenance for leaks includes testing gas shutoff valves and gas train piping for leakage.
Lining Inspections – Gradually the lining of a heat treat furnace may succumb to chipping, cracking, or bubbling. Disruptions to the integrity of the lining, left unchecked, can lead to contamination that harms the quality of the product. Lining inspections prevent contamination.
Safety and NFPA Testing – Safety and National Fire Protection Association (NFPA) testing protects clients from potential damage. It also ensures that preventive measures against workplace accidents are in place.
Roger Jones, FASM–CEO Emeritus, Solar Atmospheres (source: Solar Atmospheres)
Heat Treat Today’s Medical and Heat Treating December 2019 issue featured an article on medical alloys.Heat Treat Today asked Roger Jones, CEO Emeritus of Solar Atmospheres, Inc., to comment on how specialty medical metals are heat treated. These include titanium, niobium, tantalum, nitinol, and copper, to name a few, which in turn are used to create such standard medical devices and equipment as diagnostic guide wires, miniscule screws for implants, complex surgical tools that are operated robotically, and more. Read to see how Roger describes the hot zone and conditions under which medical device alloys are heat treated.
Vacuum furnace chambers processing titanium, niobium, chrome cobalt, and other medical device alloys are typically constructed from stainless steel. The hot zones are comprised entirely of metal (moly); graphite materials are never used in the construction of the hot zone or in fixturing parts. These furnaces process medical device alloys exclusively to avoid cross-contamination of the hot zone or the medical parts being treated.
Ultimate vacuum levels should be 1 X 10-6 Torr or better, with leak rates no greater than 2 microns Hg per hour. Gas system isolation valves aid in achieving tight vacuum, as they eliminate constant pumping on the quench system. Vacuum furnace leak up procedures are performed weekly, as well as a bake out at 2400 °F for one hour.
Horizontal, front-loading vacuum furnace with all-metal hot zone in a cleanroom setting typically used for heat treatment of medical alloys and devices (source: Solar Atmosphere)
Because of the alloys processed, cooling gases are mainly high purity argon from a liquid source. Very seldom is nitrogen used for cooling. Either type K or type N Inconel clad work thermocouples are imbedded in the loads for precise temperature readouts at +/- 10 °F or better. Processes include vacuum annealing, aging, stress relieving, solution treating, hardening, tempering, and other special processing. All furnaces are approved to the MedAccred quality standard, are surveyed to AMS 2750E, and comply with AS9100D in their processing parameters. Because the alloys are thermally treated, the vacuum furnaces operate in an air conditioned clean room with controlled temperatures and humidity levels.
Heat Treat 2019 was just a month ago, and one of the great benefits of gathering with a community of heat treaters is the opportunity to challenge old habits and look at new ways of doing things. Heat TreatToday’s101 Heat TreatTips is another opportunity to learn the tips, tricks, and hacks shared by some of the industry’s foremost experts.
Today’s Technical Tuesday features tips from Grammer Vacuum Technologies covering Vacuum Furnace and Cooilng.
If you have a heat treat-related tip that would benefit your industry colleagues, you can submit your tip(s) to doug@heattreattoday.com or editor@heattreattoday.com.
Heat TreatTip #59
Oxygen Contamination Sources
A common source of oxygen contamination to vacuum furnace systems is in the inert gas delivery system. After installation of the delivery lines, as a minimum, the lines should be pressurized and then soap-bubble tested for leaks. But even better for critical applications is to attach a vacuum pump and helium leak detector to these lines with all valves securely closed, pull a good vacuum, and helium leak check the delivery line system. Helium is a much smaller molecule than oxygen and a helium-tight line is an air-tight line. Also, NEVER use quick disconnect fittings on your inert gas delivery system to pull off inert gas for other applications unless you first install tight shut-off valves before the quick disconnect. When the quick disconnect is not in use, these valves should be kept closed at all times. (Though the line is under pressure, when you open a back-fill valve to a large chamber, the line can briefly go negative pressure and pull in air through a one-way sealing quick disconnect valve.)
Air-cooled vacuum furnace cooling system (from Dry Coolers)
Heat TreatTip #80
Closed-Loop Water Cooling Systems
Modern water cooling systems for vacuum furnaces are typically closed-loop. (By this we mean that air never comes in contact with the water that goes through your vacuum furnace. The expansion tank would be pressurized with dry nitrogen, in this case, to prevent oxygen pick-up by the water.) Sometimes after maintenance work, the expansion tank or sump is left open to air. As a result, air/oxygen, dirt, and organic materials can get into the water system and eventually cause both corrosion and plugging of your chamber. A plugged chamber can overheat and explode or implode causing serious injury or death. Replacement chambers are very expensive. A recirculating water system that allows air to contact the water entering your furnace can dramatically decrease the life of your vacuum chamber.
Heat TreatTip #89
Lanthanated Moly Alloy Strip Increases Element Longevity
Moly and TZM moly grids can double or triple vacuum furnace throughput by using a two-tier or three-tier fixture to utilize unused work zone space.
Pure molybdenum vacuum furnace heating elements distort with time in service due to growth and contraction during thermal cycling. You can often see this distortion beginning just a month or two into service of new elements. Eventually, these will contact either the insulation/shield wall— or worse yet, your parts—and cause electrical arcing. So they need to be replaced before this happens. By making a direct replacement of these pure moly strips with a lanthanated moly alloy strip, the life of the elements can be significantly increased. We have seen a rough doubling of the element life by making this change. Many new OEM vacuum furnaces are now supplied with lanthanated elements at the start. OEM and aftermarket hot zone re-builders are frequently making this change as well to get longer life out of their hot zone elements.
Heat TreatTip #101
TZM Moly Alloy for Structural Vacuum Furnace Components
For over 30 years, there has been a molybdenum alloy called TZM (Moly-0.5%Ti-0.1%Zr) which is far superior to pure molybdenum in vacuum furnace structural applications. TZM is slightly more expensive than pure moly, so OEM furnace companies use pure moly to keep their costs down for competitive reasons. But they could be offering it as an option for their buyers. Pure molybdenum metal undergoes recrystallization at temperatures as low as 2000°F. The recrystallized structure is very brittle at the grain boundaries, resulting in a structural component that also is very brittle. If you have a vacuum furnace with moly components, you have undoubtedly seen this with older parts. TZM alloy, however, does not recrystallize until around 2500°F, and even then it does not exhibit the brittle behavior of pure moly, because the recrystallized grain size is still very fine. TZM is also stronger than pure moly, as much as 3 to 4 times the strength at temperatures above 2000°F. For a 10-15% premium in cost, you can dramatically extend the life of your moly structural components in your furnaces.
Source: TAV-The Vacuum Furnace Blog
