AEROSPACE HEAT TREAT

Predicting the Effects of Composition Variation for Heat Treatment of Aerospace Alloys

/ AEROSPACE HEAT TREAT, FEATURED NEWS

In the following original content from Heat Treat Today, Thermo-Calc Software's Adam Hope, PhD, materials scientist, and Paul Mason,  president, delve into how modeling and simulation tools can help heat treaters make well-informed decisions.

This article first appeared in the latest edition (March 2020) of Heat Treat Today’s Aerospace Heat Treating magazine.

Consistency in material properties and performance is critical to the aerospace industry, and small variations in material chemistry or process windows can have a large impact on the final parts performance. The ability to predict and adjust for these variations can reduce scrap and part re-work. Metallurgists and process engineers responsible for heat treatments must adapt their process when input variables change, such as material chemistry. They are routinely faced with questions such as:

Paul Mason
President
Thermo-Calc Software

*How will heat to heat variations affect the final part performance?

*What heat treatment should be given to a part that has been built via a novel approach such as additive manufacturing?

*How should one optimize a heat treatment schedule for a new alloy?

*When the data required to make these decisions does not exist, what are the options?

Experiments can generate this data, but this is costly and time-consuming. Handbooks might have data for known alloys, but this is often only for the nominal composition and may not be suitable for material processed under a novel route. Modeling and simulation tools can help fill this knowledge gap and help inform better decisions.

 

Integrated Computational Materials Engineering and CALPHAD

Adam Hope, PhD
Materials Scientist
Thermo-Calc Software

The publication by the National Academies in 2008 on Integrated Computational Materials Engineering (ICME)[1] outlined an approach to designing products, the materials they are comprised of, and their associated materials processing methods, by linking materials models at multiple length scales. The report highlighted the need for a better understanding of how processes produce material structures, how those structures give rise to material properties, and how to select materials for a given application, describing the need for using multiscale materials modeling to capture the process, structures, properties, and performance of a material.

Computational thermodynamics, and specifically CALPHAD (CALculation of PHase Diagrams)[2], enables the prediction of the thermodynamic properties and phase stability of an alloy under stable and metastable conditions. The CALPHAD approach captures the underlying composition and temperature dependence of properties and can also be extended to model atomic mobilities and diffusivities in a similar way. By combining thermodynamic and mobility data, kinetic reactions during solidification and subsequent heat treatment processes can be simulated. Computational thermodynamics and CALPHAD- based tools are an important component of an ICME framework because, through the use of such simulations, it is possible to vary alloy compositions and predict optimal solidification processes and solution heat treatment temperature ranges without performing many time-consuming and costly experiments.

Predicting Heat Treatments for Additively Manufactured Parts

Many additive manufacturing processes subject the material to rapid solidification with multiple subsequent reheat cycles. The effect of these thermal cycles on material properties is not always known and typically does not result in the properties that a similar cast or wrought metal would have. Additionally, many additively manufactured parts are built using conventional alloys which have been engineered for cast or wrought processes. In some cases these alloys are not suitable for additive processing, and problems such as deleterious phases forming during a post-build, stress-relief heat treatment, designed for conventionally treated alloys, may result.

Additive processes are typically associated with rapid cooling rates and large thermal gradients. This can give rise to the following:

  1. High levels of residual stress in the final part
  2. Microsegregation during solidification of each layer, which leads to local inhomogeneities in alloy composition

In the case of additive manufacturing, these separate heat treatments are often combined, and stress relief heat treatments designed for cast or wrought material may not be suitable for additively processed materials for two reasons:

  1. The chemical inhomogeneities arising from rapid cooling can influence precipitation behavior, and some deleterious precipitates may precipitate more quickly than expected.
  2. The multiple heating cycles of subsequent layers may have already started some precipitation reactions, making stress relief more difficult without first homogenizing these precipitates.

Zhang et al.[3] have studied laser powder bed builds of Alloy 625 and found that after applying an industry recommended stress relief heat treatment, delta phase can precipitate in the segregated regions much faster than in the wrought material. The formation of delta phase is extremely detrimental to material properties. They attributed this to increased Nb and Mo concentrations found in the interdendritic regions in the as-built microstructure.

To understand this further, the authors first simulated the extent of this segregation using the Scheil-Gulliver model for solidification in Thermo-Calc[4] in conjunction with the diffusion module, DICTRA[4]. They then used the Precipitation module, TC-PRISMA to predict the precipitation kinetics of the deleterious delta phase for nominal feedstock compositions, as well as the compositions measured at dendrite boundaries. Both simulations, shown in Figures 1a and 1b, predict that a stable MC carbide forms, followed by some gamma double prime. Delta phase then forms at the expense of the gamma double prime. However the gamma double prime and delta phase both precipitate much more quickly in the segregated interdendritic region, due to the increased Nb and Mo. Delta phase is predicted to start forming around 1 hour, compared with 10 hours for the wrought material.

Figure 1. TC-PRISMA Precipitation simulations using nominal IN625 powder compositions (top) and segregated compositions (bottom) measured at the dendrite boundaries. Recalculated based on Reference 3.

While these calculations give insight to the reason why the conventional stress-relief heat treatment is not suitable, additional simulations can be made to identify a suitable temperature and time to both homogenize and stress-relieve the part, while avoiding deleterious phases. The authors of the study determined a post-build homogenization treatment was required to avoid deleterious delta phase precipitation.

Gas Carburizing Highly-Alloyed Steels

Highly-alloyed stainless steels can be gas carburized to increase the surface hardness, as well as improve the overall mechanical characteristics of the surface. However, an increase in chromium-rich carbides such as M23C6 or M7C3 can result in the decrease of chromium in the solid solution which leads to a reduction in corrosion resistance. Balancing these properties can be time consuming through trial and error experimentation, but CALPHAD-based tools can be used to identify suitable alloy compositions and heat treat windows, which are optimal for the application needs prior to testing in the laboratory.

Turpin et al. 5 made such a study, combining both experimental work and theoretical simulations to investigate carbon diffusion and phase transformations during gas carburization of high alloyed martensitic stainless steels. First, using thermodynamic calculations performed with Thermo-Calc 4 they determined the optimal balance between the carbide formation and chromium content of the alloy for corrosion resistance. They concluded:

  1. At 1750°F (955°C), which corresponds to the austenitization temperature of their alloy, M23C6 and then M7C3 will be the first carbides to precipitate in the austenite phase as the amount of carbon content in the alloy is increased.
  2. If the amount of carbon exceeds 3.8 wt% then M3C carbides are predicted to be stable. M3C carbides have a structure similar to cementite and preferentially precipitate at the grain boundaries which weaken the microstructure. Therefore, to avoid these phases, the overall content of carbon in the steel must be below this amount at the end of the carburizing process.
  3. Above 1.7 wt% C, the mole fraction (an indicator of the volume fraction) of M7C3 carbides exceeds 20%, and the chromium content of the alloy associated with these carbides is 65 wt%. Therefore, there is a correspondingly strong depletion of chromium from the matrix.
  4. To balance the desire for adding carbon into the matrix phase to obtain hardness with depleting the matrix of carbon, it was determined that the optimal amount of carbon in the matrix phase should not exceed 1 wt%. Thus, the thermodynamic calculations were used to establish a limit, without yet any consideration of the kinetics or time.

The second stage of the study then considered the diffusional reactions in the multi-component system during i) the carbon enrichment step and ii) the diffusion step of the gas carburizing process, and to determine how the composition and the amount of each phase vary with time and distance from the gas/solid interface and the carbon profile of the alloy as a function of time and distance. These calculations were made using the diffusion simulation software, DICTRA 4.

Consider the carbon enrichment step first. In DICTRA, several boundary conditions can be used for such a simulation, and in this work the carbon flux was determined experimentally using thermogravimetric measurements. During the diffusion step, the N2-CH4 mixture is replaced with pure N2, and the carbon flux at the surface of the samples is zero. To simulate this step using DICTRA, a zero carbon flux was applied as the boundary condition for two hours.

Figure 2 shows a simulated carbon profile for Fe-13Cr-5Co-3Ni-2Mo-0.07C, which is found to be in good agreement with the experimental values reported by Turpin et al. The authors concluded from this study that the carbon profile can be calculated and followed at any time if the boundary condition evolution at the gas-solid interface is known during the carburizing treatment.

Figure 2. DICTRA carbon diffusion profiles for Fe-13Cr-5Co-3Ni-2Mo-0.07C. Recalculated based on Reference 5.

Predicting β-transus Temperatures in Ti-Alloys

Many Titanium alloys respond well to heat treatments, through which the microstructure can be manipulated to optimize properties for a particular application. For example, some microstructures are better for high temperature creep, and some are better for fatigue strength. This is primarily achieved by controlling the nature and amount of α and β phases in the microstructure.

At high temperatures, titanium alloys are primarily β phase. At the β-transus temperature, the α phase becomes stable and can start to form. The β-transus temperature can change as a function of alloy chemistry. Knowing the β-transus temperature is critical to determining the nature and amount of α phase that will form during a heat treatment or thermal cycle.

Many alloying elements in Ti alloys have a strong effect on β-transus temperature. Knowing the actual β-transus for a specific chemistry is critical to determining suitable heat treating windows to obtain a specific set of material properties. However, even within a particular alloy specification, there can still be small compositional variations that have a significant effect on the β-transus. Thermo-Calc [4] can be used to calculate this if the exact chemistry is known, or to determine the potential distribution of β-transus temperatures for a given chemistry range.

Table 1 -- Composition specification for major elements in Ti-6-2-4-2 Alloy

Table 1 shows the composition ranges for the major elements in Ti6-2-4-2Si (AMS 4919). Figure 3 shows the calculated distribution of β-transus temperatures in the composition specification of Ti6-2-4-2. Over 40 degrees variation is possible for compositions that lie within the specification and the calculations show good agreement with the experimentally measured values of 995°C ± 15°C (1823°F ± 27°F).[6]

Figure 3. Variation in Beta transus temperature for 1000 possible compositions within Ti-6-2-4-2 specification

 

Summary

In the 100th Column of the Heat Treat Doctor [7], Dan Herring, stated that heat treating can best be defined as “the controlled application of time, temperature and atmosphere to produce a predictable change in the internal structure (i.e. the microstructure) of a material.” However, variability arising from composition differences in materials can sometimes be challenging for heat treaters. The examples shown here have illustrated how modeling and simulation tools such as those based on the CALPHAD approach can be used to predict variability arising due to material composition. HTT

References

[1] National Research Council. 2008. “Integrated Computational Materials Engineering: A Transformational Discipline for Improved Competitiveness and National Security.” Washington, DC: The National Academies Press.

[2] Kaufman, L and Bernstein, H. Computer Calculation of Phase Diagram. New York: Academic Press Inc, 1970.

[3] Zhang, Fan, et al. “Effect of heat treatment on the microstructural evolution of a nickel-based superalloy additive-manufactured by laser powder bed fusion.” Acta Materialia 152 (2018) pp 200-214.

[4] Andersson, J O, et al. “Thermo-Calc and DICTRA, Computational tools for materials science.” Elsevier, CALPHAD, Vol. 26, (2002) pp. 273-312.

[5] Turpin, T, et al. “Carbon diffusion and phase transformations during gas carburizing of high-alloyed stainless steels: experimental study and theoretical modeling.” Met. Trans. A, Vol. 36A, (2005) pp 2751-2760.

[6] TIMET datasheet for TIMETAL® 6-2-4-2, TMC-0157 (2000).

[7] Herring, D “What is Heat Treating and Why Do We Do It?” Industrial Heating Magazine BNP Media (2011).

About the authors: Paul Mason is the president and Adam Hope, PhD is a materials scientist for Thermo-Calc Software, whose products assist academia, government, and industry to make calculations which predict or assist in the understanding of complex multicomponent alloys and non-metallic systems, as well as processes of industrial and scientific relevance.

For more information, contact Paul or Adam at info@thermocalc.com or (724) 731 0074

 

(Photo source: dayamay from pixabay.com)

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Is a Nadcap Accreditation Required to Process “Nadcap” Parts?

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Nadcap is a ubiquitous topic in the aerospace industry. In this original Heat Treat Today column, veteran heat treating partner, Todd Wenzel, of Throughput/Bluestreak, shares his opinion of the accrediting of Nadcap parts.

This article first appeared in the latest edition (March 2020) of Heat Treat Today’s Aerospace Heat Treating magazine.

Todd Wenzel, president of Throughput Consulting, Inc.

First of all, I want to admit that I am not a quality manager, nor have I played one on TV, nor did I stay at a Holiday Inn Express last night. I just want to convey what I have seen in the heat treating realm regarding Nadcap accreditation. I also want to state upfront that if your company plans on aggressively pursuing aerospace part processing, it is always preferable to have your AS9100 and Nadcap accreditations in place.

My basic point to convey is that, in my humble opinion, it is not always necessary to have a Nadcap accreditation to actually process aerospace parts. Why would I make such a “treasonous” quality claim? Let me share two real examples that I have witnessed, and perhaps you have also witnessed.

Example 1

I have worked directly with many heat treating companies over the past 15+ years. Many have a Nadcap accreditation, many are in the process of obtaining it, and many that do not have it. My first example is an experience one well-respected heat treater had when setting up a new facility in a new location that would be physically positioned to tap into Nadcap work. They established this new facility and began the process of obtaining their AS9100 and Nadcap accreditation, none of which is inexpensive, as you are well aware.

Simultaneously, they started to market and talk to prospective customers about this new resource they would have for their aerospace parts. They eventually discovered that even though they had a stellar reputation in the industry, and their commitment to obtaining AS9100 and Nadcap was well documented, they found it extremely difficult, and even impossible, to move these prospective customers away from their current heat treat supplier(s) who were NOT Nadcap certified. WHAT, how could that be?!

 

Photo source: TAV Vacuum Furnaces

Well, it turns out these non-Nadcap heat treaters were “grandfathered” into the manufacturer’s supply chain. They had been processing parts before Nadcap “requirements” and had sufficient quality control to produce the required results. I’m sure there was also a cost component here since the grandfathered heat treaters did not have the added expense of obtaining and maintaining a Nadcap accreditation. Plus, there was the inherent corporate inertia to not want to change unless forced into a change, in this case suppliers.

So, what did the Nadcap accreditation do for this heat treater, completely set up to serve the aerospace industry? Bupkis.

Example 2

In this second example, there is again a well-respected heat treater who has an AS9100 accreditation, but not Nadcap. They leverage their software-based quality management system like very few other heat treaters. Nearly every piece of data they need for an audit is literally one or two mouse clicks away. They fly through audits 50%-75% faster than other heat treaters, many without any findings, and every auditor who has the opportunity to work with them is astounded at the MES/QMS system they rely upon to produce these results.

Along comes a very well-known aerospace manufacturer who is looking for other heat treating suppliers. They show up for their normal audit, and what they find is not what they were expecting. Remember, this heat treater does NOT have a Nadcap accreditation, which is supposed to be a “requirement” for processing any aerospace parts.

Their audit went much faster than normal, and they passed with zero findings, which is almost unheard of for this manufacturer of flight-critical parts. The auditor said this company is in the top tier of heat treaters he had worked with and was “blown away” by the QMS system that provided them with the flexibility to drive customer-specific production control right down to every step performed on the shop floor. Plus, all of the supporting documentation of calibrations, training, document revisions, and much more was easily available to back up the processing history.

The auditor also said that the founder of this aerospace company always emphasized that they should NOT exclude potential suppliers that are not Nadcap or AS9100; they just need to have a fully vetted quality system. Obviously, this heat treater’s MES/QMS system met that standard in spades!

Conclusion

I am NOT implying there is no value to having AS9100 or Nadcap accreditations, but what I am saying is that as long as you have a well-vetted QMS system, you should not avoid marketing your company to process aerospace parts.

Obviously, you would need specific thermal processing equipment to do so; but, a well-vetted MES/QMS system that is designed to give your company the quality “leverage” you need to compete in the aerospace market is, in many respects, the main resource you need to expand your business into aerospace and beyond.

 

About the Author: From its inception in 2004, Todd Wenzel has served as president of Throughput Consulting, Inc., an enterprise software consultancy serving the metal treating industry.

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Aerospace Fastener Manufacturer Receives Three Multipurpose Box Furnaces

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An aerospace fastener manufacturer, located in Pennsylvania, received three multipurpose bench mounted box furnaces used to test high-temperature aerospace fasteners. 

The new model GS2026, from L&L Special Furnace Co., Inc. includes a spring assist vertical lift door that allows for effortless loading and unloading even at high temperatures. The control is an industrial control system that includes a Eurotherm temperature control, overtemperature protection and a recirculation fan for uniformity.

L&L Special Furnace Model GS2026 bench mounted box furnace
(Photo source: L&L Special Furnace Co. Inc.)

The GS2026 has internal dimensions of 18” wide by 12” high by 24” deep. It has an operating voltage of 208, 220, 240 volts single phase, 60 or 50 hertz. The furnace is constructed from 3” lightweight IFB firebrick, backed up with 2” of board insulation. The elements are supported in hard ceramic element holders. These provide long element life and are easily replaced.

These additions now bring a total of five GS series furnaces at its facility.

(Photo source: spacex at unsplash.com)

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EthernetIP

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EthernetIP is the future of vacuum gauge communications for vacuum furnaces. It’s simple to integrate and improves accuracy by reducing latency from legacy analog 0 to 10 V DC outputs.

Shawn Orr, Technical Business Development Manager,
Televac – The Fredericks Company

Learn about EthernetIP and its place in your heat treat department in this Technical Tuesday original Heat Treat Today article by Shawn Orr, Technical Business Development manager with Televac – The Fredericks Company. 

This article first appeared in the latest edition (March 2020) of Heat Treat Today’s Aerospace Heat Treating magazine.

What is EthernetIP?

Figure 1.

EthernetIP (IP for Industrial Protocol) is an implementation of the digital communication standard referred to as the Common Industrial Protocol (CIP). It’s a modification of standard Ethernet and is managed by the organization ODVA, Inc. If you’re familiar with the OSI model (Open Systems Interconnection), EthernetIP defines the session layer, the presentation layer, and the application layer, with the other layers (1 through 4) defined by standard Ethernet.

EthernetIP uses standard RJ45 connectors (Figure 1) which are 8P8C (8 position 8 contact). The widespread use and availability of standard Ethernet cables makes them a more affordable solution compared to custom cables and connectors used by many manufacturers for their devices.

Figure 2. Ring topology with a PLC, MX4As, and MX7Bs. Each active gauge is connected to the previous active gauge.

EthernetIP can be configured with various topologies including ring (daisy chaining) and star (point-to-point) configurations (Figures 1 & 2). This can further reduce integration complexity and cable complexity by daisy chaining various components together on the same EthernetIP connection. Each device will have a unique IP address (or they can be grouped together in some cases depending on the implementation), but all configurations will allow you to communicate with all devices individually and digitally.

Figure 3. Star topology with a PLC, MX4As, and MX7Bs. Each active gauge is connected directly to the PLC.

Communications are done in one of two ways; cyclically (Class 1 EthernetIP connection) and acyclically (Class 3 EthernetIP connection). Cyclic communications output the same set of data over and over at a specific rate. Acyclic communications allow you to send commands and receive data back from the EthernetIP device at any time. Acyclic communications give you more control, but cyclic communications can be simpler to integrate.

How Does It Apply to Heat Treating?

So, you might be wondering, how does this apply to vacuum furnaces? All vacuum furnaces have a PLC (programmable logic controller) which is essentially the brain of the furnace. In North America, one of the most common types of PLCs is a Rockwell Automation® Allen-Bradley® PLC which has, you guessed it, EthernetIP capability! PLCs almost always have an HMI (human machine interface) where the operator can control various functions of the furnace.

The PLC takes a variety of inputs from other controllers and sensors which come in many shapes and forms. Some of the most basic are analog signals like 0 to 5 V DC or 0 to 10 V DC. Others are more complex forms of digital communication like EthernetIP. This means that you can use your PLC and HMI to take readings and adjust settings on connected EthernetIP devices.

What Are the Benefits of EthernetIP?

We already talked about some benefits of EthernetIP, but there are many others. Another significant benefit is having digital communications to your vacuum gauging and other devices on the furnace. Let’s use the example of vacuum gauge calibration.

Benefit 1 – Calibration

Many who have worked with devices on vacuum furnaces like vacuum gauges know that calibrating them can be a real hassle. Gauges often have potentiometers (sometimes called pots) that are adjusted with a set screw. This means that you’re trying to look at one reading on the HMI of your furnace while adjusting a gauge that’s possibly on top of the furnace, meaning you need two people. This is a worst-case scenario, but you get the idea; it’s not convenient.

Having digital communications over EthernetIP means that your calibration can be done from the HMI, because you can adjust the calibration digitally with most digital vacuum gauges. No more climbing on top of the furnace and adjusting pots! This is especially useful as Nadcap and AMS (specifically AMS 2769) standards become stricter, you may want to start doing more calibration at your facility instead of sending your gauges out to another facility for calibration.

Benefit 2 – Cost

One of the most significant benefits is the cost of using EthernetIP enabled devices. In addition to cheaper standard Ethernet cables, most furnaces will include other devices with EthernetIP capability, so an EthernetIP communications module for the PLC is already included. This means that if you have analog devices (such as 0 to 5 or 10 V DC), you can remove the need for costly ADC (analog to digital converter) modules by switching your devices to EthernetIP.

Benefit 3 – Power

Another benefit is powering your devices. Because there are open pins on a standard Ethernet cable with standard EthernetIP connections, it’s possible to utilize the unused pins to supply power over the Ethernet cable. There are other implementations where the power is supplied over the data lines. This is called PoE (Power over Ethernet). This eliminates the need for additional, potentially costly and complex power connections for your EthernetIP enabled devices. PoE is done many different ways, but three have been standardized by IEEE called Alternative A, Alternative B, and 4PPoE.

Benefit 4 – Accuracy

(Photo source: Solar Manufacturing/Solar Atmospheres)

The last benefit is accuracy. Using an analog signal can cause signal loss and is susceptible to signal degradation from noise depending on the cable length, particularly in industrial environments. The speed of an analog to digital conversion is also typically done with an equation and can be slow and somewhat inaccurate for a variety of reasons. Eliminating analog to digital conversions improves the latency and accuracy of readings on your HMI. No more mismatches between your gauge display and your vacuum furnace HMI!

How Do You Integrate EthernetIP into an Existing System?

Talk to your furnace manufacturer or a system integrator. First, you’ll need to make sure you have an EthernetIP enabled PLC, then you’ll need to make sure that your furnace configuration supports the addition of specific EthernetIP devices. Since each type of device communicates differently over EthernetIP, you may need to have PLC code and HMI changes made to your system to support something like an EthernetIP vacuum gauge.

About the Author: Shawn Orr is the technical business development manager for Televac – The Fredericks Company and has served as the technical liaison between its customers and engineering, responsible for identifying and implementing new growth opportunities.

(Photo Source: Figures 1-3: Televac – The Fredericks Company)

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U.S. Air Force Awards StandardAero Multi-Year MRO Contract

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Scott Starrett, president of StandardAero’s military division.

The United States Air Force (USAF) has awarded a $237 million multi-year contract to provide engine maintenance, repair, and overhaul (MRO) services for General Electric J85 turbojet engines powering the USAF fleet of T-38 trainer aircraft. The multi-year contract with StandardAero will continue into 2028.

Under the new contract, StandardAero will provide the same service the USAF has received through other multi-year contracts, including support for the USAF MRO requirements for Rolls-Royce T56 engines that power C-130 aircraft as well as General Electric F110 MRO engine support, which power international F-15 and F-16 aircraft. All of these programs are performed at the company’s San Antonio facility.

T-38 Talon trainer jet (source: Master Sgt. Lance Cheung, U.S. Air Force)

“We are thrilled to continue expanding our successful partnership supporting USAF aircraft engine MRO and the J85 program is a very strategic and logical addition to our portfolio services,” said Scott Starrett, President of StandardAero’s military division. “Our employees take great pride in helping our nation’s airmen achieve the highest level of operational readiness and mission success.”

(source: StandardAero)

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Heat Treat Radio #29: Heat Treating and Coal with Brian Joseph, CEO Touchstone Research

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Welcome to another episode of Heat Treat Radio, a periodic podcast where Heat Treat Radio host, Doug Glenn, discusses cutting-edge topics with industry-leading personalities. Below, you can either listen to the podcast by clicking on the audio play button, or you can read an edited version of the transcript. To see a complete list of other Heat Treat Radio episodes, click here.

Audio: Heat Treating and Coal with Brian Joseph, CEO Touchstone Research

In this conversation, Heat Treat Radio host, Doug Glenn, interviews Brian Joseph, the founder, CEO, and president of Touchstone Research Laboratories, about the emerging part that coal is playing in the heat treat world. Listen to find out more about the surprising uses of coal in heat treating, the development of the world's strongest aluminum, and some tips for how to make your organization run at its best.

Click the play button below to listen.

Transcript: Heat Treating and Coal with Brian Joseph, CEO Touchstone Research

The following transcript has been edited for your reading enjoyment.

We are headed to coal country, just outside Wheeling, West Virginia, to talk to Brian Joseph, founder, CEO, and president of Touchstone Research Laboratories as well as several other companies pertinent to the heat treat industry.  If you thought coal was a commodity of the past, I suggest you buckle up for one of the most interesting Heat Treat Radio episodes that will widely expand your appreciation for coal and its future uses in the heat treat industry.

I was introduced to Brian Joseph by Heat Treat Today's lead editor, Karen Gantzer, who just happens to be a relative of Brandon Robinson, a young, very sharp engineer working for one of Brian Joseph's companies, Touchstone Advanced Composites.  Brian and Brandon hosted both Karen and I at their campus in Triadelphia, WV, earlier this year, and were gracious enough to spend an entire afternoon showing us around and talking with us about some of the exceptionally fascinating esoteric work they're doing for all sorts of world leading companies in aerospace, defense, and energy as well as a host of other government agencies and national labs.  I think you'll find this episode fascinating, and I bet you're going to learn something new about coal.

Brian Joseph, Founder, CEO, and president of Touchstone Research Laboratories (source: TouchstoneAC)

Brian Joseph is the president, CEO, and founder of Touchstone Research Laboratory, as well as Touchstone Advanced Composites, Touchstone Testing Laboratory, and CFOAM Limited.

BJ:  I grew up in the panhandle of West Virginia and went to a local university, West Liberty University, and did a little bit of graduate work at Ohio State.  I then started my own business.  I never had a "job."  I've only owned my own business, and that is Touchstone Research Laboratory.  At Touchstone, we invent all kinds of things.  We put out, sometimes, a patent a month, and then we spin businesses out.  We've spun out three businesses in the last three years, and we have probably three more in the works today.

DG:  If I remember correctly, you're doing stuff for the aerospace industry and the automotive industry.  What other major markets are you hitting on?

BJ:  As you can envision, an innovative company like Touchstone Research Laboratory is far ranging.  We do a lot of work in aerospace, we do work in automotive, we do work in general manufacturing; we're inventing all kinds of things all the time.  And then there are our spin-out companies.  Touchstone Laboratory has three locations.  We do a lot of aerospace testing for virtually every aerospace company at those facilities. We test all kinds of materials at Touchstone Testing.

Then we spun out CFOAM, which is probably what we'll talk mostly about today.  This is a foam we make from coal.  In the research lab, we do a lot of coal-to-products research.  This is a foam that is extremely strong and can withstand really high temperature.  CFOAM is a publicly traded company today on the Australian stock exchange.  The applications for that are in numerous markets, one of which is in heat treating.

The third business is called Touchstone Advanced Composites.  Touchstone Advanced Composites takes the foam that CFOAM makes and builds the molds for next generation carbon fiber airplanes, rockets, etc.  Many of these are companies that you would recognize--all of the big aerospace companies, all of the commercial launches to space; we work with virtually everyone to build the molds to make their carbon fiber parts, and we do that on coal, which I think is sort of surprising to people.

DG:  I get excited about this.  This is what I want to tease our audience about a little bit, if you will, is coal.  The place of coal in heat treat.  Where might we find it currently, if at all?  And, in your mind, because I know you're very much a forward thinker, where do you see coal being used in the heat treat market, or even outside the heat treat market in the future?

BJ:  Today, the big uses for coal are electricity, to make electricity to run kilns and things.  In steel making, the coke for steel making and in cement production, we often burn coal to heat the cement.  These are current uses.

Many years ago when I was a kid, there was this basketball player that was named Lou Alcindor, and he was dunking the basketball at will and just dominating college basketball.  So they outlawed it.  They said nobody's allowed to dunk anymore.  In general, you would think that would be devastating.  But no, he just invents a special hook shot called the “sky hook” and now, all of a sudden, he can score from 20' out at will.  He became one of the highest scorers in basketball.  To me, that's what is going on in coal right now.  The things that it is dominating today, that is its primary markets, are under a lot of pressure.  But when I look out, what do I think is going to happen, is a huge number of products.

Let me tell you what we're doing right now.  We take the coal in the CFOAM business, we grind it into powder, we heat it under pressure, and we blow it up into beautiful black foam.  (Think Styrofoam only a thousand times stronger and good to enormously high temperatures, like probably up to 3000°C.)

Over at Touchstone Advanced Composites, they're building the molds to make carbon fiber airplane parts because the foam is high temperature so it will go in the autoclave.  It's very strong. It also does not expand and contract hardly at all with changes in temperature, and that's what you want in the best mold-making material.  What I get a kick out of is, you take coal out of the ground and all of a sudden we're making parts for the James Webb space telescope.

Where else will it be used?  Wow, anywhere you could think of a really high temperature.  Just imagine Styrofoam a thousand times stronger and fireproof.  Where would you use it? Everywhere.  When I think heat treatment, where do I think the obvious applications are? Kiln furniture--the strength of this stuff compresses strength of the low density material is over a thousand pounds per square inch.  Kiln insulation because it is very insulating--especially kiln floors.  Now all of a sudden, you've got a carbon floor you could walk on that is an insulator.  And, by the way, the higher density material that we make has a compressive strength so high you could set a car on one square inch and it wouldn't crush, so we're talking really high strength.

CFOAM carbon foam used as kiln furniture (source: TouchstoneAC)

You can pass electricity through it and use it as a heating element, and we've done that at times.  I could envision someone building some kilns where you lay it up like you do refractory brick today, only a carbon version of refractory brick.  One of the other ones that we don't typically think about, and is this in the heat treatment area?  I don't know, but it's sort of interesting.  CFOAM has a program with Argon National Laboratories.  Argon is working on concentrated solar power. This is the thousands of mirrors in the desert that reflect light up to a single point, and then that heats a fluid and it goes underground and it melts like a salt (like sodium chloride, like the stuff you eat) or magnesium chloride.  You're over 1400°F, so the salt is great material to hold the heat, but it's a really bad material to conduct the heat.  So we're taking the salt, putting it in the pores of the foam, and then using the ligaments of the coal foam to conduct the heat to store the energy in the salt.  Again, what I like about that is we're going to store solar power in coal, which is, again, counterintuitive.

DG:  And a bit of an irony, right?

BJ:  Yes!  I think you're going to see these carbon foams everywhere.

DG:  When we think of the heat treat industry, we certainly don't think about using coal; but in some of these new applications, like you say, being pressed in their major markets, whether it's energy production and things of that sort, there are new applications, and Touchstone Research Labs is developing some of these things.  That to me is what is interesting.

Let's talk outside of heat treat for just a minute.  I want to prime you on one of them, and then if you think of others, feel free to run with them.  You and I spoke previously about the use of coal as architectural structures in the future in place of concrete structures.  Can you hit on that a bit, and if there is anything else outside of the thermal part of coal being used outside the heat treat industry, just go ahead and roll right into those?

BJ:  We're working with a gentleman named Mark Goulthorpe.  He is an architect at MIT.  He has a program called Carbon House with the Department of Energy.  Specifically, it's an ARPA-E program, that's their real advanced technology area, and he presents this story.  He says the world population has been increasing at a very high rate of speed, but the wealth didn't spread around the world for a long time, so people didn't have much money, they didn't make much, and they didn't buy much, so we didn't notice them so much.  But what's happened in the last 20 years, maybe the greatest accomplishment of man in the last 20 years, is we've reduced that extreme poverty 80% worldwide, which is just extraordinary.  So now, all of a sudden, the complex part of this is that these people are moving to cities at a rate of a million people a week.  That means, inside 30 years, we will need to double the number of houses and buildings on the surface of the earth inside 30 years.  The construction boom has already started.  Imagine you've got to build a million, I'll say apartments, and office buildings and things every week until after the year 2050.  He points out, what are we going to build all of this out of?  There is not enough wood on this planet.  You can't use concrete.  If we're concerned about global climate change and that puts out more carbon dioxide than burning coal, so what are our options?  He points out that the answer is probably buried in our hydrocarbons.  Things like methane to carbon nanotubes where we take the carbons and the methane and we make carbon nanotubes.  That will be part of the structure.  Take the hydrogen and make that the fuel.

And at MIT, that's what they're thinking the future is.  And CFOAM will probably play a major role in these kinds of structures because at the end of the day, the coal that we make the foam from is very inexpensive, available in extraordinarily large quantity, and can make fireproof structures that are inexpensive and with a pretty low carbon footprint.  The production of the foam is a very small carbon footprint production.  It does not produce much pollution or production of much CO2 and that kind of thing.  So it's fairly green.  It's funny to talk about coal in a green way, but it really is a pretty green product.  And that may be the thing that gets us there.

DG:  Yes. And compared to the manufacturing of concrete, it's a lot greener manufacturing the CFOAM panels, let's say, as opposed to concrete.

Clean Room (source: TouchstoneAC)

BJ:  Yes, absolutely.  Some fun things to talk about for just a minute:  Over at Touchstone Advanced Composites, we've made the molds to make parts for the James Webb space telescope.  This will be the greatest telescope, I think, the world has ever produced.  I think it's 8 times bigger than Hubble, it will be located a million miles from earth, just so everyone can have a little yardstick, that's four times the distance to the moon, and it will see back in time till to the creation of some of the first galaxies.  We've made all of these parts on molds made from coal.

We just finished building the molds to make the communications dish antenna for the NASA wide field infrared telescope, which is the size of Hubble, and that is going up soon.  We just finished the structures that will be on a solar sail for NASA.  Let me tell you what a solar sail is:  Imagine a kite, only square.  So you have two sticks on a kite.  We're going to make those out of carbon fiber, but we're going to make them in a special way that collapse, so that they go into a box 2' x 2', but when you get up into space, you open this box up and this rolls out 54 ½ ' in all directions.  You end up with this 110' solar sail that is up in space.  What's going to happen is, the light from the sun moves this thing.  Just the light, no propellant.  It will go 240 thousand miles an hour.  And we've built all the molds from CFOAM that we make from coal.

We do work with virtually every one of the commercial launches to space.  We just did the front end of a supersonic aircraft and dozens of other new aircraft that are being built.  All of that is being done on CFOAM.  That's a whole group of fun things we do.

DG:  Can you tell us about MetPreg?

BJ:  At Touchstone Research Laboratory, we're developing the world's strongest aluminum.  This is aluminum with fibers in it.  It's aluminum oxide fibers in aluminum.  What's really interesting about it is it's the highest temperature aluminum that exists, so this will be useful at temperatures up to 1000°F.  It will keep 80% of its strength.  It's 3 times stronger than the world's strongest aluminum alloy.  This is not made from coal.  This is aluminum with fibers.  We either make it in a tape form or pultruded form, or we make it into cylinders by film winding it, like you do polymer composites.  It is a whole new class of materials, and our plan is to spin that out into a separate company, probably within the next year or so.  Right now we're developing the business plan.

We are doing this on-scale already.  It's already been put on a ship.  One of the applications, by the way, is repairing the structures in large ships, especially aluminum hold ships, for fatigue in particular.  Some of these ships are tracking hundreds of fatigue cracks in the structural component, and we can use this as a patch to repair the ships while at sea and have a permanent repair.  This is an application, by the way, that I wouldn't have even come up with.  This is one that the navy came to us and said, is this something you guys could do? So we've been working in a development program with the navy.  It about a million dollar program.  While in the program, we're already on our first ship and we're really excited about that.  That application is ready to go but many of the other applications are still in development.

DG:  You've already run down a list of some of your customers, but maybe just give us a sense of the breadth and depth of your customer base, as many as you're comfortable telling us about.

MetPreg Rocket Motor Casing (source: TouchstoneAC)

BJ:  On the aerospace side, it's virtually everyone in aerospace, from your Boeing and Airbuses, Embraer, to some of your smaller ones that are suppliers to that industry.  We have hundreds and hundreds of people, especially using the CFOAM.  In terms of MetPreg, we're not there yet with flying on airplanes, but I'm really confident we will get there.  We can probably mention the work we do with Virgin. I love Richard Branson, by the way. He is a hero of mine; I think the world of him.  We've done work with some of his companies--Virgin Orbital, Virgin Galactic. They are two separate companies. Virgin Galactic is the one that's going to take people into space.

I want to spin back around and talk about what that means, taking people to space.  The thing we think about is rich people going for joy rides, which is good, and there is a market.  But don't think of it like that.  I think he's building this next generation aircraft that, for example, we'd take off from LA.  Well, it's just as easy to drop you in Chicago as it would be back to LA, in fact I think it's easier.  So I see this is as the beginning of a new way to fly around the world.

I'll give you another one--SpaceX.  They have a similar vision. SpaceX rockets are very different.  They're going to land vertical.  Richard Branson's is going to look like an airplane.  It's going to be more normal looking, but they won't go that fast; they'll go a couple thousand miles/hour maybe, whereas SpaceX is going to go like 18,000 mph.  I saw the president of SpaceX give a talk.  (In fact, by the way, one of our people got to meet Elon Musk just a few weeks ago, and he came back with the biggest grin on his face.)  So the president of SpaceX, says, "I do a lot of business in Riyadh, and I can't wait for the day that I take off from here in California, fly to Riyadh, (it will take about 40 minutes and most of that is landing), and then we'll fly back home in time to fix dinner for the family." It just made me smile. Gwynne Shotwell is awesome in every way.

Now Virgin Orbital is different.  Virgin Orbital shoots rockets up in the air.  They come off of a Boeing 747 that they've named 'Cosmic Girl,' and then it goes into orbit.  That does go fast.  It is not to carry humans, it's to put satellites in orbit.  It's an inexpensive way to put satellites in orbit.  You fly the 747 as high as you can, you tilt it a little bit upwards and you shoot your rocket right into orbit.  It's a lot less expensive than launching from the ground.  That's another one of Richard Branson's businesses and they have a great team of people working there.  I'm really optimistic about it.

For your heat treatment people, think about the temperatures we're dealing with.  The rocket motors are all super high temperature, just through the atmosphere.  It takes you up into the thousands of degrees.  So all the things your client base works with is what the outside of all of these vehicles is.  It's just interesting.  And yet, I don't know that they think in that world right now.  When you look at the number of launches going into space right now, we in the United States don't track what's going on around the world so much, so I'll give you just one example.  Rocket Lab has what they call the Electron rocket.  It will be launched from New Zealand.  Now, I was unaware that New Zealand ever launched a rocket, it's just not something I was aware of.  They're planning to launch 300 launches a year--in New Zealand!  So, what do you think the worldwide going in and out of space is going to be here in the next decade or two? I think it's going to be really large.  And markets for things like thermal protection systems or high temperature components is going to be much bigger than anyone realizes.

DG:  Shifting just a little bit.  Obviously, the organization that you've developed, Touchstone Research Laboratory, etc., your whole organization, all of them, have been very innovative.  Can you speak to the, let's say, culture there and the method by which you push the innovation?  How do you make such an innovative organization?

BJ:  You may have picked up on something with that question.  You've been here, you've walked through, and you have a feel for how we sort of work.  I went to Dearborn, Michigan, once and I went to the Henry Ford Museum in Greenfield Village.  (If anyone has never been there, you've got to go, especially if you like technical things.)  And there, Henry Ford bought Edison's first research laboratory and rebuilt it there.  It's four buildings, so you walk through the world's first industrial research laboratory.  I went there one day about 4 years ago, and I was not necessarily a big Edison fan.  I knew who he was and everything, but when I walked into this building, it was like something was overly familiar.  So I said to my wife, “I have to go back there and spend a day by myself just in the buildings and just look around.”

Here's what I figured out:  As you know, I never "got a job." I went to graduate school, came out, and started my own research laboratory from scratch.  I didn't know all of the modern processes to manage a laboratory.  So I'm sort of figuring out from scratch as a kid in my twenties and trying to work my way through.  And what I ran into was a process that ends up being almost identical to what Edison did.  I'm not saying I'm smart like Edison, I'm just saying that my invention process ended up remarkably similar.  Here's how it goes: In R&D, you need some well educated people, they've got their PhD from Berkeley or MIT or wherever, for example.  But then there is this other group that fabricates stuff.  This person, maybe from MIT, says, “Hey, what if we make this vacuum chamber and heat in this way with microwaves and then we put UV light in?” and that's my idea on Monday morning.  Now it's about how fast can we turn that into something real, run our experiments, and get to the next thing.  In R&D, the thinking part is seconds, minutes, or hours, but the doing part is usually days, weeks, and months.  So if you want to collapse your time of invention, you work on that second side, and you get the best technicians you can.  And they make the people with the high degrees look really smart.  So it's how you blend those together that I think can create this really unique environment, and I think that's sort of money that tricks behind what we do.

(source: TouchstoneAC)

In addition to that, we're a real flat organization and things like that. There are a lot of things that people don't know about Edison's management approach, but he dressed down for work. He didn't want to be seen as the boss at work. He just blended in and went from person to person. When investors would show up, people would be running around, saying, “Get him cleaned up!” At work, he didn't have any airs about him, which is the right answer. The more central control you have, the less your organization has that ability to just run. You've got to handle your organization very gently. He was the first guy to ever build an industrial research facility. He did amazingly well with it, but he was less than perfect. In recent years, there's been a lot of complaints about the details of what he did, but he was the guy out there blazing the trail, so I give him a lot of credit for that.

DG:  Let's circle back around to CFOAM for just a moment.  CFOAM, current and future, especially where it hits on the heat treat market.  Where would we see CFOAM?  You mentioned the fact that the mechanical properties are very strong, it could be used for floors and furnaces, it could be used for hearth piers, hearth rails, could be used for the sides of furnaces.  One of the issues in the heat treat market that we have to be careful about is, you know, the guys on the forklifts who smash the trays into the sides of the furnace during loading and unloading.  I assume there is some strength here in the CFOAM that you might not have another especially ceramic materials, but also maybe some of your metal walls, if you will.

BJ: The foam can be made in a wide range of densities too.  When you were here, I think I showed you two densities that we predominantly manufacture today. One is 20 pounds/cubic foot and the other is 30 pounds/cubic foot. But you can make it up to 90 pounds/cubic foot, which at that point it is massively strong and very high temperature, but not as insulating.  There is a trade-off between insulation and strength.  So what we can do for some of those applications is dial in "what is the appropriate mechanical properties versus thermal properties for an application?" because the technology is really robust that way. In fact, one of the challenges to new materials like this is deciding what is the thing I want to make this week.  Because you can offer all kinds of things, so you have to figure out what are the things you think your customers want.  If customers look at our properties and they're not exactly what they need, there is a good chance we could make some adjustments and make something with either more conductivity, less conductivity; in fact, there is a whole group of things we haven't talked about, which is the other end of the spectrum--very high thermal conductivity foams.  We have some foams that we can make with the thermal conductivity of aluminum at one-fifth the weight.  To me, is there a market?  Does this relate to heat treaters?  It's not obvious to me, and I'm not down on the details of that business, but it wouldn't surprise me at all if someone listening doesn't say, “You know, that's exactly what we need! A carbon that's very thermally conductive.”  So that's the other end of the spectrum.

DG:  So you can make the foam either thermally insulative or conductive, either way?

BJ:  That's right.  And we can bury the electrical properties through ten orders of magnitude, from 10 million ohm centimeters to .1 ohm centimeters.

DG:  The question that jumps into my mind, and this may not be a fair question to ask you, but let me ask it anyhow: The commercial viability of these CFOAM products in the heat treat market.  You can use them as heating elements, I assume.  I don't think we see much.  We see a lot of graphite heating elements, but heating elements, I assume for structural parts, perhaps.  The one that jumps to my mind, and I think I mentioned it to you when I was there, was radiant tubes, which are the metal tubes are somewhat, they have a life cycle, let's put it that way.  Because of thermal cycling, they do tend to, at some point in time, crack or whatever.  We have some companies that are making radiant tubes out of ceramic-type material, but there are sometimes issues with breakage.  My thinking is, is it possible that perhaps we could get coal based radiant tubes even, that are very strong yet very thermally conductive?

BJ:  Yes, I think such a thing would be possible.  I can't tell you that I could give it to you tomorrow afternoon, but absolutely.  I think the material can do it.  I think we can figure out how to actually make that on volume. I think that's very doable.

Another thing: the foam is porous.  Are there situations where you want to bring nitrogen in through the wall at really, really low speeds for some reason, while heating to very high temperature? I don't know; or any other gas--hydrogen or whatever.  I haven't had that need, but I'm not in that particular marketplace that might have that need.

Doug Glenn, Publisher, Heat Treat Today
Doug Glenn, Heat Treat Today publisher and Heat Treat Radio host.

To find other Heat Treat Radio episodes, go to www.heattreattoday.com/radio and look in the list of Heat Treat Radio episodes listed.

Heat Treat Radio #29: Heat Treating and Coal with Brian Joseph, CEO Touchstone Research Read More »

Future Heating of Industrial Furnaces

/ AEROSPACE HEAT TREAT, BURNERS & COMBUSTION SYSTEMS TECHNICAL CONTENT, FEATURED NEWS, OP-ED

Climate change and fossil fuels are topics that can spur many lively conversations. In today’s Heat Treat Today Technical Tuesday feature, explore their connection as it relates to heating industrial furnaces in the future with Dr. Joachim G. Wüenning, president, WS Inc. and an expert in clean efficient combustion.

This article originally appeared in Heat Treat Today’s  March 2020 Aerospace print edition.

 

Joachim G. Wüenning, President of WS Inc.

Many people view climate change as the biggest threat to mankind. Technical and social efforts will be required to meet the goals, formulated in the “Paris Climate Agreement,” to limit global warming to less than 35.6° F (2° C).

Combustion of fossil fuels is by far the largest human contribution to global warming. Fossil fuel-fired power plants and internal combustion engines are already in the public focus. The transformation to alternative drives for vehicles has just started, and the days of coal-fired power plants are numbered.

Combustion of fossil fuels for industrial furnaces is also a large contributor to greenhouse gases and air pollution. The industrial heating sector is not in the public focus yet, but that will change soon; therefore the topic should be addressed proactively.

For mid- to long-term future industrial process heating, there are three main scenarios:

  • heating with renewable electricity, or
  • heating with non-fossil fuels, or
  • a combination of both.

Humans used non-fossil fuels for hundreds of thousands of years and are returning to that habit after a short period of about 250 years where fossil fuels were primarily used.

Reducing CO2 Now and In the Future

Heating a furnace using electricity is locally CO2 free, but an even greater amount of CO2 is emitted at power plants since the majority of electricity is generated by burning fossil fuels. For every kilowatt hour (kWh) produced, roughly one pound (~0.45kg) of CO2 is emitted into the atmosphere [1]. This is true for Germany, and the figures for the United States are in the same range.

Heating an industrial furnace with a typical temperature of around 1832°F (1000°C) with natural gas produces about 0.4kg CO2 for every kWh of available heat for a cold air burner, and less than 0.25kg/kWh CO2 when using a recuperative or regenerative burner where waste heat is recovered using a heat exchanger.

So, the short-term measure to reduce CO2 emissions is to use an efficient burner with heat recovery or to switch from electric to natural gas heating, which can cut CO2 emissions by 50% or more.

For a further reduction, we have to wait until electricity generation becomes predominantly regenerative, or we have to use green, non-fossil fuels. The possible paths to non-fossil heating of industrial furnaces are drafted in Figure 1. It shows that the short-term action should be improving the efficiency of burner systems or a switch from electric to gas heating. In the mid- to long-term future, there should be a healthy competition between non-fossil fuel gas and electricity, driving the prices for non-fossil energy down.

Figure 1

Changing Fuel Compositions

The most relevant characteristic for the interchangeability of fuel gases is the Wobbe Index (Figure 2), with the lower or upper heating value (Hi, Hs), the density of the fuel gas (r) and the density of dry air (r0). Fuel gases with the same temperature, pressure, and the same Wobbe Index will provide the same energy output from a burner. If the Wobbe Index is changing, the flow must be corrected by changing the fuel gas pressure or a flow throttle device to keep the burner power constant.

Figure 2

In most cases, the air does not need to be corrected since the ratio between stoichiometric air ratio and lower heating value is about 0.95 m3/kWh for common hydrocarbons. That means that a burner with a given heating power needs the same amount of air even when different fuel gases are used. A good rule of thumb is that one cubic meter per hour of air is required for every kilowatt of heating power.

If hydrogen is used as a fuel, about 15% less air is required. So, when hydrogen is added to natural gas and the fuel gas flow is corrected but the air flow is left unchanged, the system would be operated with somewhat more excess air, slightly less efficient but safe.

If gas fluctuations will occur in the future, adjusting the burners with more excess air would be an easy measure to ensure safe operation. With an effective heat recovery system and low exhaust gas temperatures, efficiency losses would be minimal.

Fuel Gases With High Hydrogen Content or Pure Hydrogen

The flame speed of hydrogen is much faster compared to hydrocarbons. That can cause some problems, especially in premixed burners where a flashback can occur. Another challenge resulting from faster combustion could be higher flame peak temperature leading to higher thermal NOx emissions. Modern low NOx methods are available to address this problem.

A positive effect of hydrogen can be a more reliable and easier ignition of burner systems. Many industrial burner systems can be operated with high percentages of hydrogen or with pure hydrogen with little or reasonable modifications.

Fuel Gases Containing Fuel Bound Nitrogen

Using ammonia or bio-gases with fuel bound nitrogen will produce excessive amounts of NOx-emissions when burned in most burner systems. There are a number of options to achieve low NOx-combustion with fuel bound nitrogen.

One method is fuel conditioning where fuel bound nitrogen is broken up into molecular nitrogen. This was successfully demonstrated using a stainless steel reactor in combination with a flameless oxidation burner system.[2] Another method would be exhaust gas cleaning by selective (SCR) or non-selective (SNCR) catalytic exhaust gas cleaning. Both processes require large investments and operating costs and should only be used if other options are not available.

The development of combustion systems with integrated treatment of fuel bound nitrogen would be the preferred method and will be an important topic for combustion research in the coming years. One approach is multi-stage flameless oxidation [3].

Fuel Conditioning

Fuel conditioning might be required to keep fuel gas properties within regulated limits inside the gas transport and distribution grid or for certain customers with special requirements. Fuel conditioning can be performed by blending different gases or by changing their compositions by using reformers or gas separation units like pressure swing adsorption (PSA) or membrane technology.

If future regulations propose a certain hydrogen content in the fuel gas grid, strategically placed steam reformers could keep the hydrogen content within certain ranges, even if there is no regenerative electricity available to operate electrolysers.

Reformers could also crack ammonia, ethanol, or methanol before being used as fuel gas to heat processes.

Outlook

There are several options towards non-electric, fossil-free industrial process heating. All these options have to be thoroughly investigated to keep a number of options open for future energy systems. The energy system of the future will be based on regenerative power generation but it will involve additional energy carriers to store and transport the energy. There are some challenges for combustion but there is no doubt that these can be overcome.

A fair and open competition between the different energy options will create the best solutions for society and the planet. A planned economy will not provide the fertile soil for innovations and entrepreneurship necessary to meet the challenges.

References

[1]    German Environment Agency, CO2 Grid Emission Factors from 1990 – 2018 for the German Energy Mix, March 2019

[2]    Domschke T., Becker C., Wüenning J.G., Thermal Use of Off‐Gases with High Ammonia Content – a Combination of Catalytic Cracking and Combustion, Chem. Eng. Technol., 21: 726-730

[3]   Wüenning J., Multistage Flameless Oxidation, AFRC Combustion Symposium, Waikoloa, HI, September 2019

 

About the Author: Joachim G. Wüenning is president of WS Wärmeprozesstechnik GmbH and his area of expertise is in clean efficient combustion, FLOX—flameless oxidation, heat recovery, radiant tubes, and recuperative, regenerative burners. This article originally appeared in Heat Treat Today’s  March 2020 Aerospace print edition.

 

(Image source: Seagull from pixabay.com)

 

Future Heating of Industrial Furnaces Read More »

West Coast Aerospace Company Purchases Custom Batch Tempering Furnace

/ AEROSPACE HEAT TREAT, AEROSPACE HEAT TREAT NEWS, ATMOSPHERE AIR FURNACES NEWS, FEATURED NEWS

A commercial heat treating company located in the heart of the aerospace industry on the West Coast of the United States recently commissioned a custom built batch tempering furnace. With a working load size of 168” wide, 48” deep, and 48” tall, coupled with a max load weight of 10,000 pounds, the furnace from Gasbarre Thermal Processing Systems can accommodate a number of differently sized parts within its market.

The gas fired air furnace passes survey at +/- 10℉ over a temperature range of 850℉ to 1350℉ per AMS2750E. At the customer’s request, the electrical controls are UL approved and include the latest in Eurotherm brand temperature controlling instrumentation.

(source: Gasbarre Thermal Processing Solutions)

(Image source: John Torcasio, unsplash.com)

West Coast Aerospace Company Purchases Custom Batch Tempering Furnace Read More »

Aerospace Standards in the Heat Treating Industry

/ AEROSPACE HEAT TREAT, AEROSPACE HEAT TREAT NEWS, FEATURED NEWS

Have you ever wondered how to create or revise AMS specifications? In this original Heat Treat Today Technical Tuesday feature, come along with Andrew Bassett, president of Aerospace Testing and Pyrometry and an expert in aerospace pyrometry specifications, as he shares his experience and knowledge in the process.

Andrew Bassett, President, Aerospace Testing and Pyrometry

Author’s Note: These comments are the non-binding opinion of the author and do not constitute an interpretation by SAE. Such opinions do not replace the need to ensure agreement between the supplier, customer, and cognizant engineering organization.

This article originally appeared in Heat Treat Today’s  March 2020 Aerospace print edition.

Those who are familiar with aerospace heat treating are accustomed to Aerospace Material Specifications (AMS) that guide heat treaters on how to process parts and raw materials. These specifications will mandate equipment requirements, atmospheres to be used, cleaning methods, soaking times and temperatures, and testing requirements, to name a few. The working committee, Aerospace Metals Engineering Committee (AMEC), is in charge of revising these specifications, which is required every five years. This is a long and sometimes tedious process of revising specifications with many knowledgeable experts involved.

There are various types of specifications that have been established by the SAE Technical Standards Board:

  1. Aerospace Material Specifications (AMS)
    • These technical reports contain specific performance requirements and are used for material and process specifications conforming to sound established engineering and metallurgical practices in aerospace sciences and practices.
  2. Aerospace Standards (AS)
    • These technical reports contain specific performance requirements and are used for design standards, parts standards, minimum performance standards, quality, and other areas conforming to broadly accepted engineering practices or specifications for a material, product, process, procedure, or test method.
  3. Aerospace Recommended Practice (ARP)
    • These aerospace technical reports are documentations of practice, procedures, and technology that are intended as guides to standard engineering practices. Their content may be more general in nature, or they may offer data that has not yet gained broad acceptance.
  4. Aerospace Information Report (AIR)
    • These aerospace technical reports are compilations of engineering reference data, historical information, or educational material useful to the technical community.

To create or revise an Aerospace Specification, a “sponsor” of the specification will request to either create a new or revise an existing standard with the approval of the chairperson. Once the approval has been granted, the sponsor will work to create and/or revise the existing document. When the draft document is complete, the draft is balloted for a 28 Day Ballot. Members of AMEC can make comments on the ballot with either a “T” comment or an “I” comment. The “T” comment is a technical error, missing requirement, or improper requirement that needs action by the committee. All technical comments should be accompanied by a reason for the comment and a suggested improvement to resolve the issue. The “I” comment is a non-technical correction. These may include spelling and grammatical mistakes, incorrect paragraph numbering, and the like. Each “T” comment must be discussed and voted on by the committee members and approved or disapproved. During the ballot process, members are asked to “Approve” or “Disapprove” the ballot. This process goes on until no more changes are required to the draft before the document is sent to the appropriate commodity committees.

The illustration (Figure 1) describes the creation/revision process for given specifications.

 

(Click on image to enlarge)

Figure 1. Ballot Process Flowchart from SAE

 

The projects for the revisions to AMS-2759 series of specifications started in 2009/2010 with many of the draft revisions waiting in “parking lots” until all the specifications were completed. Since their release in 2018, several of these specifications had to be revised again due to missing or omitted requirements or small changes to clarify issues.

Over the last eighteen months, the heat treat industry has experienced new revisions to the following specifications (revision dates):

  1. AMS-2759 Rev G Heat Treatment of Steel Parts General Requirements (04-23-19)
  2. AMS-2759/1 Rev H Heat Treatment of Carbon and Low Alloy Steel Parts Minimum Tensile Strength Below 220 ksi (1517MPa) (09-19-19)
  3. AMS-2759/2 Rev J Heat Treatment of Low Alloy Steel Parts Minimum Tensile Strength 220 ksi (1517MPa) and Higher (07-15-19)
  4. AMS-2759/3 Rev H Heat Treatment Precipitation-Hardening Corrosion-Resistant, Maraging and Secondary Hardening Steel Parts (01/07/19)
  5. AMS-2759/4 Rev D Heat Treatment Austenitic Corrosion-Resistant Steel Parts (04-28-18)
  6. AMS-2759/5 Rev E Heat Treatment Martensitic Corrosion-Resistant Steel Parts (04-28-18)
  7. AMS-2759/6 Rev C Gas Nitriding of Low Alloy Steel Parts (06-11-18)
  8. AMS-2759/7 Rev D Carburizing and Heat Treatment of Carburizing Grade Steel Parts (04-15-19)
  9. AMS-2759/8 Rev B Ion Nitriding (06-11-18)
  10. AMS-2759/9 Rev E Hydrogen Embrittlement Relief (Baking) of Steel Parts (10-18-18)
  11. AMS-2759/10 Rev B Automated Gaseous Nitriding Controlled by Nitriding Potential (06-11-18)
  12. AMS-2759/11 Rev A Stress Relief of Steel Parts (04-28-18)
  13. AMS-2759/12 Rev B Automated Gaseous Nitrocarburizing Controlled by Potentials (07-02-18)
  14. AMS-2759/13 Gaseous Nitrocarburizing (06-11-18)
  15. AMS-2769 Rev C Heat Treatment of Parts in Vacuum (07-12-19)
  16. AMS-2770 Rev P Heat Treatment of Wrought Aluminum Alloy Parts (04-08-19)
  17. ARP-1962 Rev B Training and Approval of Heat Treating Personnel (06-11-19)
  18. ARP-7446 Vacuum Gauge Calibration (03-06-19) New ARP

There are several more projects underway that include the revision of AMS-H-6875, Heat Treatment of Steel Raw Materials that will become a four-digit AMS Specification, AMS-2774, Heat Treatment Wrought Nickel Alloy and Cobalt Alloy Parts, AMS-2801, Heat Treatment of Titanium Alloy Parts and AMS-2750, Pyrometry, to name a few. As new technology emerges, such as additive manufactured metal parts, AMS standards will need to be revised or created to address the thermal processing of these parts.

AMS-2750 (Pyrometry) is one of the more contentious specifications, which is currently under revision, because it is the main specification for the testing of thermal processing equipment. This specification not only has an effect on commercial heat treaters working in aerospace, but this specification has been adopted in chemical processing/coatings for baking/drying ovens, composites for curing and bonding laminates, and as of January 28, 2018, the FDA Center for Devices and Radiological Health has added this standard to its list of recognized consensus standards database. For those who are heat treating medical devices such as needles, heart wires, titanium staples, and metallic joint replacements, AMS-2750 is now governing how the thermal processing equipment will be tested.

When I first became involved with AMEC in June 2008, the AMS-2750D (Pyrometry) was starting to be revised to AMS-2750E. I attended my first meeting in Niagara Falls, New York, with the expectation that I would be working only with a group of aerospace primes who write these standards. As it turned out, many of the members at AMEC are end users, such as captive and commercial heat treaters who are experts in the specifications in which they are involved. Since being in the field of pyrometry, I thought I would volunteer my time and expertise on the revision of AMS-2750. The sub-team group consisted of experts from Boeing, Honeywell, Carpenter Technology, Alcoa, Performance Review Institute (PRI), and Bodycote Thermal Processing with each team member bringing to the table his/her own knowledge and expertise in pyrometry. The process of revising this specification took four years to complete with numerous team meetings to discuss and propose changes to better clarify the previous revision. The final revision was finally published in July of 2012. Since then, I have been involved with other specifications such as AMS-2769 (Heat Treatment of Parts in a Vacuum), ARP-7446 (Vacuum Gauge Calibration), and the next revision of AMS-2750F.

Getting involved with AMEC and the various commodity groups is rewarding as it allows you to have a voice in the specifications that affect your business. You work with other members in the heat treat community to develop and create specification to enhance the industry, better the process, and continually strive to deliver quality parts or materials.

About the Author: Andrew Bassett is the president of Aerospace Testing and Pyrometry and is an expert in aerospace pyrometry specifications. He has 25 years of experience in the calibration and testing of thermal processing equipment. This article originally appeared in Heat Treat Today’s  March 2020 Aerospace print edition.

 

(source: Stefan Fluck on Unsplash)

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A Tour of Common Hazards in the Heat Treat Industry

/ AEROSPACE HEAT TREAT, AEROSPACE HEAT TREAT NEWS, FEATURED NEWS

Rick Kaletsky, Owner, Safety Consultant

Safety is a concern to all industries, but it’s of paramount importance for the aerospace manufacturing sector. Join us on this whirlwind tour of a heat treat shop from the perspective of an industry safety consultant, Rick Kaletsky. Rick’s a funny guy, but don’t let that detract from the critically important information he has to share. Rick Kaletsky is an MTI OSHA Safety Consultant and the author of the popular book, OSHA Inspections: Preparation and Response, 2nd Edition.

This column is being supplied courtesy of the Metal Treating Institute and was first published in the Heat Treat Today Aerospace magazine in March 2019.

With all of the bright and shiny new gadgets and technology in the heat treat industry, it’s easy to overlook the wealth of the “same old” classic hazards, which may not have been properly dealt with in the shop. It is critical to address these basic (often severe) risks/violations rather than be distracted by trying to identify new-to-the-forefront issues. Please note that this list is surely not all-inclusive. I’ll make this concise as we tour the shop and highlight areas that demand attention.

Let’s take a look:

  • Are you still allowing obstacles to impede immediate access to exits, fire extinguishers, electrical disconnects, and emergency eye fountains?
  • Are you permitting unguarded (or improperly guarded) power transmission equipment, highlighted by chain drives, belt drives, couplings, and gears?
  • Have you adequately guarded fan blades?
  • Are you adhering to the (chemical) hazard communication program— especially the labeling, safety data sheets, and
    training? (Also, don’t forget the Globally Harmonized System.)
  • Is the lockout/tagout program (relating to unexpected energization and release of stored energy) sufficient— attaining ZES (zero energy state addressing electrical, mechanical, pneumatic, hydraulic, spring, thermal, steam, gravity+), only one “available” key per personal lock, machine-specific procedures, and more?
  • What kind of permit-required confined-space program have you implemented—a detailed, super priority, tackling matters of oxygen deficiency, vapor ignition, entrapment, and so on, with a fully integrated plan including (but not limited to) space identification, permit system, calibrated instrumentation, attendants, and non-exposed rescuers?

All set now? WAIT! There’s more that is routinely violated on a regular basis. These items above, and more to follow, are not simply matters of technical non-compliance with the law of the land. They are scenarios waiting to ambush workers and leave them with burns or worse (from fire, explosion, and electrical sources), mangled digits and limbs, blindness, lung damage, and many other examples of preventable misery.

Abatement can be motivated by a desire to avoid “breaking the law and paying the price.” It can be motivated by ethics and the sincere “touchy feely” desire to “do the right thing.” Yet it can also be motivated by a company’s knowledge that employee protection is good business, with very tangible, financial results. The cost of occupational injuries and illnesses can decimate your profit line far more than direct medical costs. It is worth considering all of the follow-up medical bills, cleanup, overtime, downtime, insurance rate increases, and much, much more, not to mention the enhanced OSHA penalties.

Pardon the diversion; now for a look at some more key questions:

  • Is heat stress considered to be a very real concern (and met head-on as an occupational hazard) rather than viewed as a mere matter of degrees of comfort?
  • Has there been a full assessment of personal protective equipment needs?
  • Is safety-toed footwear required, as determined by such an assessment?
  • How about eye protection (consider different forms for different hazards), hand protection (again, particular types for particular risks), hearing protection, flame-resistant/retardant clothing, and whatever else is brought to light by way of a thorough assessment considering each task to be performed?
  • Are the extinguishers conspicuous, fully charged, and professionally tested on a timely basis?
  • Who is expected to use the extinguishers, and have those employees been “hands-on” trained?
  • Are compressed gas cylinders well-secured, capped (where designed to be), and properly separated (oxygen from fuel gas, in storage)?

Have I offered enough tips? No? Okay, here are just a few more points to ponder:

  • Are electrical cords in good condition, without (for instance) stripped/cut/burned insulation, damaged/missing grounding prongs, or similar damage? (Remember that portable electrical tools can be double-insulated, as an alternative to grounding.)
  • Is there accurate, unambiguous, easy-to-read labeling on disconnects, breakers, controls, and so on?
  • If there are breaker slots without breakers, are those spaces filled with blanks?
  • Are electrical boxes and similar apparatus equipped with approved covers?
  • Are forklift trucks and similar vehicles properly maintained, with emphasis on steering, brakes, horn, tires, overhead guard, and fork movement reliability; are all operators suitably trained?
  • How about the elimination or deep mitigation of trip and slip hazards?
  • What have you done (including by engineering means and specific training) to decrease exposure to ergonomic hazards, especially regarding backs?

There’s always more that can be done to improve safety and minimize risk in the shop, and it’s usually something easily overlooked in regular safety checks that turns up flagged in a review. But don’t let the procedure blind you to the most important reason we stress safety in the shop: the welfare of our employees.

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