OP-ED

Why Heat Matters and the Need for Speed

/ BURNERS & COMBUSTION SYSTEMS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, OP-ED

In this installment of Technical Tuesday, Jim Roberts of U.S. Ignition engages readers in a Combustion Corner editorial about the role of velocity in heat treating — breaking down how faster burner speeds create more turbulence in the furnace, which helps parts heat up faster and more evenly.

This editorial was first released in Heat Treat Today’s June 2026 6th Annual Buyers Guide Issue print edition.

A furnace guy walks into a heat treat plant and looks around. While it all looks calm and controlled, the agitation inside the furnaces is rampant.

So many times, we forget to slow down, look over our shoulders, and see all we’ve accomplished or learned. Combustion Corner series began with the intent to take a simple, almost primer-level look at what combustion-related issues the modern heat treater — furnace technicians, production managers, and really everybody involved in the process — may encounter.

The focus has been on burners and flame-related items. Occasionally, we get questions for an opinion on considering gas-fired versus electric furnaces or other similar questions. That’s dangerous ground to tread because so many different processes can use both. In fact in most cases, the method of heating is really moot to the process goal: Get heat delivered, cleanly, and all will be well with the parts and the process.

With that in mind, let’s take a peek at what really matters in heat treating. It’s the heat. Specifically, it’s how to get heat delivered as quickly as possible and with as much control as is possible. I know, kind of obvious that heat is important in heat treating. There are “four modes of heat transfer,” but we’ll just look at one of them today.

Convective Transfer

Convective transfer is an easy one because we see so many practical applications in our own homes. The new ovens in the modern home are often convection ovens and seemingly everybody has an air fryer. In the kitchen alone, you can see this how heat transfer increases can happen via convection increases. Take this principle to the shop floor and you can see how critical it is in processes that allow contact with flue gases or hot air.

We used to heat up the box of bricks, and once it got to the needed temperature for the metallurgy requirement, we would push in a basket of parts and wait for them to catch up to that temperature. The thermal mass of the load would literally suck the heat right out of the box, and the temperature would crash. Then, we’d wait for the temperature to stabilize. Once there, the old rules of time and temperature would apply.

But what if we wanted to speed up the process? What if we wanted more even temperature delivery and more temperature uniformity? The word that comes to mind in most burner intrinsic processes is velocity.

Velocity

We talked about how some direct-fired burners are now designed to give fantastic exit velocities from the burner and into the furnace chamber. And when I say fantastic, it has to do with comparing what was an acceptable burner design back in the early days of industrial America when burner flame/flue gas exit velocity of direct-fired heat treating was like 40 MPH. New burners of today have exit velocities of almost 500 MPH!

Here is why it matters: Velocity will have a direct effect on the heat transfer, firstly by blasting into the “boundary layer” of gases that circulate around parts in the furnace. And most flue gases have been laminar in nature, but with this increased turbulence, the agitation of these gases allows more direct contact with the actual part.

The Reynolds Number

This increased turbulence results in a higher Reynolds number. The Reynolds number (Re) is a dimensionless quantity in fluid mechanics that predicts flow patterns — laminar (smooth) or turbulent (chaotic) — by calculating the ratio of inertial forces to viscous forces.

The word viscous reminds us that all things flowing around in the furnace are considered fluid from a scientific viewpoint. Interestingly, all this turbulence also results in greater mass transport. Remembering that the part or load has some mass, once it begins to heat up, it actually begins to emit heat as well. This mass transport mechanism is a result of the turbulence moving the heated molecules away from the surface of the part more quickly, which maintains a higher temperature differential, and again, increases heat transfer.

I guess what we are doing here is starting with velocity on a burner-level discussion, and we will discuss multiple methods and scientific quirks regarding the big picture — heat transfer. We will discuss some of the basics of heat transfer and explore comparisons between conduction, radiation, and convection, and more.

Till next time…

About The Author:

Jim Roberts
President
US Ignition

Jim Roberts president at U.S. Ignition, began his 45-year career in the burner and heat recovery industry focused on heat treating specifically in 1979. He worked for and helped start up WB Combustion in Hales Corners, Wisconsin. In 1985 he joined Eclipse Engineering in Rockford, IL, specializing in heat treating-related combustion equipment/burners. Inducted into the American Gas Association’s Hall of Flame for service in training gas company field managers, Jim is a former president of MTI and has contributed to countless seminars on fuel reduction and combustion-related practices.

For more information: Contact Jim Roberts at jim@usignition.com.

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Answers in the Atmosphere: Hydrogen Part 2 — Costs and Gas Blend Generation

/ ATMOSPHERE GENERATORS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, OP-ED

In this installment of Answers in the Atmosphere, David (Dave) Wolff, an independent expert focusing on industrial atmospheres for heat treat applications, examines the cost dynamics of hydrogen as a process gas and the blended atmospheres strategies thermal processors use to manage them. Drawing on insights from Stephen Feldbauer PhD of Abbott Furnace, Wolff walks through the key gas blend options available to operators and how operators select the most cost-effective mix for the job.

This informative piece was first released in Heat Treat Today’s May 2026 Sustainable Heat Treat Technologies print edition.

In last month’s column, we discussed hydrogen as a process gas and addressed key attributes. In that column and in the one that follows, Stephen Feldbauer PhD, director of Research & Development at Abbott Furnace, provided key insights.

A Question of Cost

Stephen Feldbauer PhD
Director of Research & Development
Abbott Furnace

Hydrogen gas is relatively expensive; in fact, case studies conducted by Abbott Furnace have demonstrated that atmosphere costs often constitute over two-thirds of the variable costs of thermal processing. Hence, cost savings in hydrogen-containing atmosphere supply are important.

As a result, thermal processors will preferentially employ gas blends, containing just the right amount of hydrogen to get the job done, diluted in a larger volume of inert or non-problematic diluent gas. Think of it like using a small amount of powerful dish soap diluted with a large volume of water to effectively clean a large amount of pots and pans. The primary advantage to using hydrogen-blended atmospheres is that they are much less expensive than using pure hydrogen.

Hydrogen-Nitrogen Blended

Pure hydrogen, delivered or generated on-site, may be blended with pure nitrogen to reduce atmosphere costs. While nitrogen can be delivered as a gas or liquid, it can also be separated from atmospheric air on-site at low cost to produce a hydrogen-nitrogen blended atmosphere. Hydrogen-nitrogen blended atmospheres typically range in hydrogen content from about 3% to 75% hydrogen, with the balance nitrogen. Nitrogen costs the thermal processor about 20% of the cost of hydrogen for a similar volume of gas, so blending hydrogen with nitrogen may be a useful approach to obtaining the benefits of a hydrogen-based atmosphere at substantially lower cost.

The actual blend of hydrogen and nitrogen used is primarily determined by the metal that is being thermally processed. As the oxide of one metal may be more stable and difficult to reduce than another, the amount of hydrogen is often increased to make the atmosphere more active. Some metals will be adversely affected by nitrogen at high temperatures. Thermal processors using a hydrogen-nitrogen atmosphere will use furnace atmosphere mixers to blend the leanest (lowest hydrogen) atmosphere that yields acceptable results in the finished metal parts.

Image Credit: Abbott Furnace

A widely used generation approach to a hydrogen-nitrogen atmosphere is to use a thermal catalytic reactor (a “dissociator”) to crack metallurgical grade ammonia (NH₃) to a gas blend of nominal 75% hydrogen, 25% nitrogen (based on the ratio of nitrogen and hydrogen atoms in the ammonia starting gas). Because ammonia is a commonly used agricultural and industrial chemical, ammonia is widely available and cost-effective. Ammonia is delivered by truck in pressurized liquid form and stored in a tank for use.

The resulting atmosphere gas blend is generally called dissociated ammonia (DA). Significantly less expensive than using pure hydrogen, DA gas is a popular gas blend if a nitrogen-containing gas blend can be used. If decreased reducing potential is acceptable, generated DA gas can be further diluted with pure nitrogen to reduce costs even more.

Generation from Hydrocarbon

Another approach to cost-reducing hydrogen-containing atmospheres is to generate a hydrogen-containing atmosphere from a readily available hydrocarbon, such as natural gas, propane, or even methanol. This is possible because these hydrocarbons can be thermally cracked using a catalytic reactor to liberate free molecular hydrogen gas in a blend with other constituents. These reactors may use partial combustion in the case of Exothermic reactors to make Exo gas, or they may use pure thermal cracking, avoiding combustion, in which case the technique is called Endothermic gas generation, and the resulting gas is often called Endo gas.

Because Exo gas is a result of partial combustion with air, an Exo gas blend has approximately 10% hydrogen and considerable nitrogen in it, whereas Endo gas has approximately 40% hydrogen and very low levels of nitrogen. Because both Exo and Endo gases contain considerable carbon (originating from the fuel gas), their uses are limited to processes and materials where the carbon content does not create processing issues.

Argon-Hydrogen Blend

Many of the stainless steel grades cannot be thermally processed in nitrogen-containing atmospheres because the nitrogen gas will react with the chromium, damaging the alloy. In that case, an argon-hydrogen blend may be employed. Because argon is more expensive than hydrogen, the economics of an argon-hydrogen gas blend may result in much higher levels of hydrogen in the furnace atmosphere.

About The Author:

David (Dave) Wolff
Industrial Gas Professional
Wolff Engineering

Dave Wolff has over 40 years of project engineering, industrial gas generation and application engineering, marketing, and sales experience. Dave holds a degree in engineering science from Dartmouth College. Currently, he consults in the areas of industrial gas and chemical new product development and commercial introduction, as well as market development and selling practices.

For more information: Contact Dave Wolff at Wolff-eng@icloud.com.

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Answers in the Atmosphere: Hydrogen Part 1 — Powerful Reducing Properties, High Thermal Conductivity

/ ATMOSPHERE GENERATORS TECHNICAL CONTENT, BULK GASES & SYSTEMS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, OP-ED, SINTERING POWDER/METAL TECHNICAL CONTENT

In this installment of Answers in the Atmosphere, David (Dave) Wolff, an independent expert focusing on industrial atmospheres for heat treat applications, examines the powerful reducing properties and high thermal conductivity that make hydrogen a critical atmosphere in metal thermal processing.

This informative piece on hydrogen’s role in sintering, annealing, and surface protection — including how it is sourced, how it behaves inside the furnace, and how operations can safely manage this flammable atmosphere under NFPA 86 — was first released in Heat Treat Today’s April 2026 Annual Induction Heating & Melting print edition.

Hydrogen is widely used in metal thermal processing for sintering of powdered metal fabrication technologies and for heat treatment (e.g., annealing, brazing) of bulk metal manufactured components. This column draws heavily from an interview the author had with Stephen Feldbauer Ph.D., director of Research & Development at Abbott Furnace. Abbott Furnace is a leading furnace manufacturer for continuous furnaces and furnace controls. As R&D Director, Steve leads Abbott’s work in pioneering furnace advances with a special focus on debinding and sintering.

Why Hydrogen?

Stephen Feldbauer, PhD
Director of Research & Development
Abbott Furnace

Hydrogen provides two desirable characteristics to heat treaters: very high chemical reducing potential and the highest thermal conductivity of any gas. The high reducing potential enables hydrogen to convert heated metal oxide coatings to pure metals. This is extremely helpful for successful sintering of powder metallurgical parts. Superior thermal conductivity enables rapid part heat up and cool down. Compared with either vacuum or inert gas atmospheres, hydrogen enables much faster throughput and achieves shorter furnace cycles.

Hydrogen-containing atmospheres are required to successfully sinter most iron-based metal parts, whether manufactured by powder metallurgy (PM), metal injection molding (MIM), or binder-jet metal additive manufacturing techniques. As-received, the iron-containing metal powders used for these advanced fabrication techniques are covered with an iron-oxide coating, making it virtually impossible to successfully sinter the particles together under reasonable temperature conditions. Reducing the oxide coating enables successful sintering.

Hydrogen-based atmospheres used with a tube or strand furnace are the primary surface protective technology used for drawn components (e.g., wire, tubing, and profiles). Hydrogen simultaneously protects the part surface from oxidation and allows metal to anneal, which softens it and restores toughness after it has been hardened by the drawing process.

Sourcing Hydrogen

Because of its high reactivity, hydrogen is almost never found in nature as a pure gas (H2). Instead, it is generally found as a component in a compound like water (H2O) or a hydrocarbon gas or liquid, such as methane (CH4), propane (C3H8), or longer hydrocarbon. In order to be used as a thermal processing atmosphere, hydrogen is liberated from these hydrogen-containing compounds to exist as a pure gas while in use in the hot furnace.

The liberation of elemental hydrogen from its compound carrier can happen at a remote plant operated by an industrial gas company provider, in which case the hydrogen would be compressed or liquified for delivery to the thermal treatment client, or may be conducted at the site of the thermal processor themselves through use of on-site generation equipment. User choices of approaches to pure hydrogen supply will be covered in future columns.

Inside the Furnace

Inside the hot furnace, hydrogen changes metal oxide coatings to pure metals by preferentially reacting with the metal oxides to produce pure metal and water vapor. Thus, the furnace atmosphere dewpoint (a measure of gaseous water content) will increase as the hydrogen simultaneously creates pure metal surfaces and produces water vapor as a byproduct. The water vapor is swept out of the furnace and replaced by the clean furnace atmosphere that flows counter current to the heated metal product. Furnace atmosphere controls for hydrogen-based atmospheres use dewpoint as a key operating parameter.

Hydrogen’s ability to protect the part surface from oxidation is critical in the annealing process. | Image Credit: Abbott Furnace

Since furnaces must open to admit parts for thermal processing, the furnace, the atmosphere system, and the procedures must all be designed to prevent unsafe conditions caused by hydrogen leaking out of the furnace, or air leaking in. Furnaces intended for a flammable gas atmosphere use doors, curtains, and pilot lights (i.e., flame curtains) to prevent hydrogen or other flammable gas from leaving the furnace without being combusted. These precautions avoid explosions inside or outside the furnace.

Furnaces for hydrogen-containing atmospheres utilize unique design and construction approaches to safely use this flammable atmosphere. In the U.S., furnace design and operation is guided by NFPA 86, the furnace code. NFPA 86 defines certain furnace design features and also defines standard operating techniques for safe operation with a combustible atmosphere, such as a hydrogen-containing atmosphere. Similar codes and standards are used in other countries.

Next month, this column will pick up the question of cost by looking at options for generation of hydrogen atmosphere blends. Generation of pure hydrogen will be a future topic.

About The Author:

David (Dave) Wolff
Industrial Gas Professional
Wolff Engineering

Dave Wolff has over 40 years of project engineering, industrial gas generation and application engineering, marketing, and sales experience. Dave holds a degree in engineering science from Dartmouth College. Currently, he consults in the areas of industrial gas and chemical new product development and commercial introduction, as well as market development and selling practices.

For more information: Contact Dave Wolff at Wolff-eng@icloud.com.

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Keeping the Burners in Tune

/ BURNERS & COMBUSTION SYSTEMS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, OP-ED

Jim Roberts of U.S. Ignition engages readers in a Combustion Corner editorial about keeping industrial burners in tune — examining how everything from simple orifice plates to sophisticated burner control units (BCUs) and P-type radiant tubes drive efficiency and temperature uniformity in modern heat treating furnaces.

This editorial was first released in Heat Treat Today’s April 2026 Annual Induction Heating & Melting print edition.

In part 2 of this series (Aerospace Heat Treating, March 2026), we talked about how balancing the pressure can save gas and reduce emissions. So, how do they do it?

Figure 1. ECOMAX® with eductor and burner control unit BCU | Image Credit: Honeywell

There are some fairly sophisticated and exacting control systems that can use flow meters that compensate and monitor pressure fluctuations. The air and gas valving will then react to inputs from the orifice meters and pressure monitors. Some systems may even extract a sample of the flue gas at the exhaust, much like the sensors on your automobile catalytic converter. The use of these burner control units (BCUs) keeps burners tuned to exacting performance. A lab setup example of that technique is shown in Figure 1.

Other setups are quite simple and perform at their best on the normal setting. In other words, if the process temperature is 1850°F, engineers design burners to perform optimally at that temperature and for thermal input to be achieved 90% of the time. In this scenario, orifice plates and control valves set for that optimum performance hold the combustion system steady at that input; variations are minimal.

The burners may not run perfectly when coming up to heat, but that is hopefully a short-term situation, and as the furnace comes up to heat the burner, systems settle into a desired tune range. Think of these as the dragsters at a racetrack. We’ve all seen how they shudder and quake while waiting to go flat out down the racetrack. But when gas is pushed into them, they blow fire, smooth out, and go to unbelievable performance levels. Only we furnace guys would make that comparison… or maybe just this guy.

It bears noting that recirculation patterns can take on many variations depending on the type of heat treating you may be doing. Direct fired systems for stress relieving and straight up hardening operations use a high velocity direct fired system (Figure 2). That is where the aforementioned eductor pulls the flue gases out of the furnace and over the heat exchanger. Recirculation takes place in front of the burner in a high velocity stream exiting the nozzle. A percentage of the chamber gases gets pulled into that flue stream.

Figure 2. ECOMAX® in direct heating
systems | Image Credit: Honeywell
Figure 3. Examples of the design and the flue gas flow pattern | Image Credit: Honeywell
Figure 4. Schematics of P-type and double P-types tubes | Image Credit: Honeywell

In the case of controlled atmosphere furnaces, where radiant tubes are utilized for the heating system, all sorts of different techniques exist. In the designs of recuperative recirculating style burners (i.e., FGR burners, flue gas recirculation), the tube designs are diverse and varied. Early designs of single ended tubes (SER) were the first to utilize recirculation designs (Figure 3).

Later, steel mills began to experiment and use P-type and double P-type tubes for strip annealing lines and galvanizing lines (Figure 4). You can see in these figures that the flue gases get pulled around, and we get the benefit of heat we have already generated and gas we have already burned. This creates a very good improvement in tube temperature uniformity and heat delivery. The arrows on the figures show the flow pattern of the gases.

So, in conclusion, there is no conclusion. Design improvements will continue to be made as long as we have requirements for efficient and emission-responsible operations in our heat treating plants and furnaces. Understanding that the world requires heat treating to be available for just about everything, and that we need to address those needs with ever-improving technologies… now THAT is pressure.

Till next time.

About The Author:

Jim Roberts
President
US Ignition

Jim Roberts president at U.S. Ignition, began his 45-year career in the burner and heat recovery industry focused on heat treating specifically in 1979. He worked for and helped start up WB Combustion in Hales Corners, Wisconsin. In 1985 he joined Eclipse Engineering in Rockford, IL, specializing in heat treating-related combustion equipment/burners. Inducted into the American Gas Association’s Hall of Flame for service in training gas company field managers, Jim is a former president of MTI and has contributed to countless seminars on fuel reduction and combustion-related practices.

For more information: Contact Jim Roberts at jim@usignition.com.

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Answers in the Atmosphere: Argon Part 2 — Market Perspectives

/ BULK GASES & SYSTEMS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, OP-ED

In this installment of Answers in the Atmosphere, David (Dave) Wolff, an independent expert focusing on industrial atmospheres for heat treat applications, examines the market realities shaping argon supply and demand.

This informative piece on argon’s sourcing and distribution landscape, safety considerations, and emerging growth drivers — from U.S. titanium refining and powder metallurgy to the reshoring of domestic steel production — was first released in Heat Treat Today’s March 2026 Annual Aerospace Heat Treating print edition.

Akin Malas
Business Development Manager / Metallurgist
Linde

If you are just beginning to read this column, welcome. I encourage you to read the February 2026 installment to have a better understanding of the attributes of argon as an industrial gas for the thermal processing industry. Akin Malas, business development manager and metallurgist at Linde, joins me in this foray into argon, and we’re exploring market realities in this installment.

Though many companies compete for market share in the supply of gases such as nitrogen, oxygen, and hydrogen because they are relatively less expensive to source and process, the number of companies that have sufficient scale and expertise to produce and market argon is generally considered to be limited to the top tier of industrial gas companies like Linde, Air Liquide/Airgas, Air Products, Matheson, and Messer. Many other companies operate ASUs; however, very few of the plants are large enough to separate and purify argon. In the case of some ASUs owned and operated by very large steel mills, they generally sell their crude argon to industrial gas suppliers for purification and subsequent marketing and sales.

Linde gas delivery truck | Image Credit: Linde

Argon is delivered as a liquid cryogenic product (LAR), like liquid nitrogen (LIN), or liquid oxygen (LOX), but there may be differences in the storage and dispensing equipment installed at a client’s site due to the variety of uses for argon. Certain high-volume applications, such as ladle stirring and metals atomization, may require substantially higher pressure than normal cryogenic tanks are set up to store, making the use of boosters or cryogenic pumps necessary. If your application requires argon pressure to be above 100 psig, make sure that you are talking to a supplier that is experienced in providing and maintaining the equipment needed for your process.

From an NFPA codes standpoint, argon storage is comparable to nitrogen storage, and the clearances in NFPA 55 are the same for argon and nitrogen. But there are some key points to consider as far as safety in use:

  • While all cryogenic gases will create a vapor cloud that hugs the ground if there is a release, the clouds from nitrogen and oxygen will disperse and rise relatively rapidly as the gas warms. But because argon has much higher density than oxygen and nitrogen, a release will tend to hug the ground and can create a serious oxygen deficient atmosphere issue in low spots. Users of pit furnaces with argon need to be particularly aware of the unique characteristics of argon.
  • Because argon is generally shipped much longer distances than oxygen or nitrogen, tanks tend to be larger sized so that more can be delivered in a single visit. Since the transportation element of the price is considerable, keep in mind that your tank size (and NFPA clearance calculations) may be different than is typical for nitrogen.

While argon cannot be cost-effectively produced from air by non-cryogenic generation techniques (like membrane and PSA techniques used for nitrogen and oxygen), argon recovery/recycling is possible from argon-based industrial streams. A few of the larger industrial gas providers can provide recycling equipment that uses cryogenic separation technology to re-create very high purity argon from argon-rich offgas streams. Note that these installations are relatively expensive and specialized and are generally only of interest to the largest argon consumers.

After many years of relatively modest growth in the consumption of argon, several market segments are driving potentially important growth in argon use:

  • Several companies are developing U.S.-based titanium refining capabilities. Argon is required for processing and refining titanium metal, and the U.S. titanium production may become an important consumption driver.
  • Virtually all atomization of the special metals for powder metallurgical applications currently is done with argon used as the atomization gas. Though cheaper water-based atomization is being developed, it is not yet suitable for high quality powders. The metals powder industry has experienced strong growth and continues to grow.
  • The U.S. is reshoring iron and steel production, meaning that argon use for ladle stirring will rise. This means that overall argon use will rise, and that some new argon-capable ASU capacity will be built to serve the needs of new and refurbished steel plants.

Akin and I hope that these last two column installments have helped readers understand the factors in the market for argon that make it different in several ways from the more familiar nitrogen/oxygen marketplace.

About The Author:

David (Dave) Wolff
Industrial Gas Professional
Wolff Engineering

Dave Wolff has over 40 years of project engineering, industrial gas generation and application engineering, marketing, and sales experience. Dave holds a degree in engineering science from Dartmouth College. Currently, he consults in the areas of industrial gas and chemical new product development and commercial introduction, as well as market development and selling practices.

For more information: Contact Dave Wolff at Wolff-eng@icloud.com.

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Ask The Heat Treat Doctor®: Why and How Do We Heat Treat Gears? Part Two

/ AEROSPACE HEAT TREAT TECHNICAL CONTENT, CARBURIZING TECHNICAL CONTENT, HARDENING TECHNICAL CONTENT, INDUCTION HEATING TECHNICAL CONTENT, OP-ED, QUENCHING TECHNICAL CONTENT, VACUUM FURNACES TECHNICAL CONTENT

Ask The Heat Treat Doctor® has returned to bring sage advice to Heat Treat Today readers and to answer your questions about heat treating, brazing, sintering, and other types of thermal treatments as well as questions on metallurgy, equipment, and process-related issues. In this installment, Dan Herring continues his discussion on gear heat treatment, exploring vacuum and induction hardening methods for gears — from low-pressure carburizing for advanced materials to single shot and tooth-by-tooth induction techniques — and how each can be matched to the specific demands of any gear application.

This informative piece was first released in Heat Treat Today’s March 2026 Annual Aerospace Heat Treating print edition.

In Part One of this discussion (Air & Atmospheres Heat Treating, February 2026), we discussed various gear types, materials, and how they can be atmosphere heat treated. This month, we are focusing on vacuum and induction heat treating methods. Let’s learn more.

Vacuum Heat Treatment Processing Methods

Table A. Advanced Materials Processed by LPC

Vacuum processing can be used for most of the atmosphere treatments mentioned in Part One including carburizing (Figure 1). Low pressure carburizing (LPC) is a proven technology and the choice for many advanced applications in aerospace, automotive, off-highway, and motorsports markets, as well as the development of carburizing cycles for high-performance materials (Table A).

Figure 1. Typical commercial heat treat load of gears for vacuum carburizing (Otto and Herring 2007) | Image Credit: Photo courtesy of Midwest Thermal-Vac
Figure 2. Pyrowear 675 – LPC – anneal – double normalize – harden – anneal – deep freeze – double temper | Image Credit: The HERRING GROUP, Inc.

The range of effective case depths for most of these grades can range up to 2.0–3.0 mm (0.080–0.120 inches) without significant sacrifice of microstructure (Figure 2). Furnace variables, such as temperature uniformity (± 3°C or ± 5°F), control of cycle parameters (boost/diffuse times, gas flow rate, pressure, hydrocarbon type) and surface carbon optimize the microstructure, producing case uniformities of ± 0.05 mm (± 0.002 inches). Where permitted, the range of carburizing temperatures now includes the use of high temperature (> 980°C, or 1800°F) techniques.

All these advanced materials required extensive development testing to produce custom designed recipes to optimize cycle parameters. Also, quenching methods (Otto and Herring 2002) have improved, allowing us to achieve desired core properties with quenching parameter selection (high-pressure gas or oil) for distortion-sensitive and distortion-prone part geometries (Otto and Herring 2005, 2008).

Induction Hardening Methods

Various methods of hardening via applied energy are used in manufacturing gears, including flame hardening, laser surface hardening, and induction hardening.

Of the various types of applied energy processing, induction hardening is the most common. Induction heating is a process that uses alternating electrical current that induces a magnetic field, causing the surface of the gear teeth to heat. The area is then quenched resulting in an increase in hardness within the heated area. This process is typically accomplished in a relatively short time. The final desired gear performance characteristics are determined not only by the hardness profile and stresses but also by the steel composition and prior microstructure. External spur and helical gears, bevel and worm gears, racks, and sprockets are commonly induction hardened. Typical gear steels include AISI/SAE grades 1050, 1060, 1144, 4140, 4150, 4350, 5150, and 8650.

Figure 3. Patterns produced by induction hardening (Rudnev 2000)

The hardness pattern produced by induction heating (Figure 3) is a function of the type and shape of inductor used, as well as the heating method. Quenching or rapidly cooling the workpiece can be accomplished by spray or submerged quench. The media typically used for the quench is a water-based polymer. The severity of this quenchant can be controlled by the polymer’s concentration. Cooling rates are usually somewhere in between what would be obtained from pure water and oil. In some unusual situations compressed air or nitrogen is used to quench the part.

The most common methods for hardening gears and sprockets are by single shot (Figure 4) or the tooth-by-tooth method (Figure 5). Single shot often requires large kW power supplies but results in short heat/quench times and higher production rates. This technique uses a circumferential copper inductor, which will harden the teeth from the tips downward.

Figure 4. Typical single shot induction hardening operation | Image Credit: Photo courtesy of Ajax-Tocco-Magnethermic
Figure 5. Tooth-by-tooth induction hardening of a helical gear | Image Credit: Photo courtesy of Ajax-Tocco-Magnethermic

The larger and heavier loaded gears (where pitting, spalling, tooth fatigue, and endurance are issues) need a hardness pattern that is more profiled like those produced by carburizing, which can be obtained by tooth-by-tooth hardening. This method is limited to gear tooth sizes with modulus 4.23–5.08 (6 or 5 DP) using frequencies from 2 to 10 kHz and about 2.54 (10 DP) using a range of 25 to 50 kHz.

The lower the frequency, the deeper the case depth. Tooth-by-tooth hardening is a slow process and usually reserved for gears and sprockets that are too large to single shot due to power constraints. The process involves heating the root area and side flanks simultaneously, while cooling each side of the adjacent tooth to prevent temper-back on the backside of each tooth. The induction system moves the coil at a pre-programmed rate along the length of the gear. The coil progressively heats the entire length of the gear segment while a quench follower immediately cools the previously heated area. The distance from the coil to the tooth is known as coupling or air gap. Any changes in this distance can yield variation in case depth, hardness, and tooth distortion. The gear is indexed after each tooth has been hardened, often skipping a tooth. This requires at least two full revolutions in the process to complete the hardening of all teeth. Straight, spur, and helical gears up to 5.5 m (210 inches) weighing 6,800 kg (15,000 lb) have been processed with this method. The entire process yields a repeatable soft tip of the tooth with hard root and flank. In other applications, the tip and both flanks can be hardened simultaneously and yield a soft root.

In Summary

Today’s design engineer has the good fortune of being able to choose from a number of heat treatment technologies for any given type of gear material and design. When selecting a gear hardening method, it is essential to specify not only the desired mechanical and metallurgical properties, but the critical dimensions that must be held and even the desired stress state of the gears themselves. The secret to success is understanding the advantages and limitations of each technology and taking these into consideration when determining the overall cost of gear manufacturing.

References

Herring, Daniel H. 2004a. “Gear Heat Treatment: The Influence of Materials and Geometry.” Gear Technology, March/April.

Herring, Daniel H. 2004b. “Reducing Distortion in Heat-Treated Gears.” Gear Solutions, June.

Herring, Daniel H. 2007a. “Oil Quenching Technologies for Gears.” With Steven D. Balme. Gear Solutions, July.

Herring, Daniel H. 2007b. “Heat Treating Heavy Duty Gears.” With Gerald D. Lindell. Gear Solutions, October.

Herring, Daniel H. 2012–2016. Vacuum Heat Treatment. Vols. 1–2. BNP Media Group.

Herring, Daniel H. 2014–2015. Atmosphere Heat Treatment. Vols. 1–2. BNP Media Group.

Herring, Daniel H., Gerald D. Lindell, D. J. Breuer, and B. Matlock. 2001. “Atmosphere vs. Vacuum Carburizing.” Heat Treating Progress, November.

Herring, Daniel H., Gerald D. Lindell, D. J. Breuer, and B. Matlock. 2002. “An Evaluation of Atmosphere and Vacuum Carburizing Methods for the Heat Treatment of Gears.” In Off-Highway Conference Proceedings. SAE International.

Otto, Frederick J., and Daniel H. Herring. 2002a. “Gear Heat Treatment: Today and Tomorrow, Part 1.” Heat Treating Progress, June.

Otto, Frederick J., and Daniel H. Herring. 2002b. “Gear Heat Treatment: Today and Tomorrow, Part 2.” Heat Treating Progress, July/August.

Otto, Frederick J., and Daniel H. Herring. 2005. “Vacuum Carburizing of Aerospace and Automotive Materials.” Heat Treating Progress, January/February.

Otto, Frederick J., and Daniel H. Herring. 2007. “Advancements in Precision Carburizing of Aerospace and Motorsports Materials.” Heat Treating Progress, May/June.

Otto, Frederick J., and Daniel H. Herring. 2008. “Improvements in Dimensional Control of Heat Treated Gears.” Gear Solutions, June.

Rudnev, V. 2000. “Gear Heat Treating by Induction.” Gear Technology, March/April.

About the Author

Dan Herring
“The Heat Treat Doctor”
The HERRING GROUP, Inc.

Dan Herring has been in the industry for over 50 years and has gained vast experience in fields that include materials science, engineering, metallurgy, new product research, and many other areas. He is the author of six books and over 700 technical articles.

For more information: Contact Dan at dherring@heat-treat-doctor.com.

For more information about Dan’s books: see his page at the Heat Treat Store.

Ask The Heat Treat Doctor®: Why and How Do We Heat Treat Gears? Part Two Read More »

“Just Balance the Pressure,” They Said

/ BURNERS & COMBUSTION SYSTEMS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, OP-ED

Jim Roberts of U.S. Ignition engages readers in a Combustion Corner editorial about the hidden complexity of balancing furnace pressures — explaining how thermal expansion, gas velocity, and pressure fluctuation interact in modern burner systems, and how flue gas recirculation can push firing efficiency from 30% to 75% while cutting NOx emissions by more than half.

This editorial was first released in Heat Treat Today’s March 2026 Annual Aerospace Heat Treating print edition.

When I made the comment about the negative attitude in Part 1 of this series (Air & Atmosphere Heat Treating, February 2026), I was referring to the fact that most of these burner designs require a suction component (in this case, the eductor) to help pull the exhaust gases out over the heat exchanger portion of the burner. Also, if we just tried to pressurize the burners and force the exhaust gases out through the exchanger section, there would be a pressure buildup in the furnace. With that comes the destruction of door seals. Burner plates begin to leak, and when the doors open, the operators and furnace guys get greeted with a blast of 2000°F flue gas. I can honestly say, I have not, in all my years in this industry, met a furnace guy who likes a thermal haircut.

So, by balancing the pressures, we can save gas, reduce emissions, and probably even heat treat some products along the way.

A comment like, “just balancing the pressures,” seems like such an easy thing to accomplish. And, for all the experienced furnace guys out there, that is probably regarded as pretty simple stuff. But we have to give proper respect to the myriad of moving parts in today’s modern burners and heating systems. When I say moving parts, perhaps the better description is designing around the fluctuations in pressures, temperatures, and flows that these modern systems all perform to operate at these efficiencies.

When Combustion Corner covered pressures and velocities in August and September 2025, you will recall that under these temperatures, everything starts moving around under the temperature growth and pressure increases. Velocity increases like crazy, and at heat treating temperatures, the very components expand significantly enough to affect the pressure and delivery of flue gases.

High temperatures cause flue gases to expand significantly because increased thermal energy boosts gas molecules’ kinetic energy, making them move faster and spread out. This principle, described by gas laws like Charles’s Law, leads to volume increases that necessitate expansion joints in equipment to prevent system damage and maintain integrity. This expansion can create immense stress on combustion systems, requiring specialized components like expansion joints to absorb thermal growth and maintain seals, while the high heat can also induce chemical changes and dissociation, influencing performance in other ways.

For example, can you begin to envision how furnace designers and burner design engineers have to pay attention to component growth while maintaining the critical pressures of the furnace and the burners and heat exchangers? It’s a dance, let me tell you! I believe I pointed out a while back that a 6-inch diameter radiant tube or burner combustor will grow almost an inch in length when running at 1400°F and above. If it’s growing in length, it is also trying to grow in diameter. It’s like trying to produce a constant flow of water at a constant spray rate on your garden hose, all the while the hose is changing dimensions. Not so easy is it?

To sum up, with heat recovery, and then with the addition of flue gas recirculation and high velocity burners, it is really quite remarkable how well many of these systems perform. The firing efficiency of a flue gas recirculation system over a conventional cold air burner can be the difference of 30% fuel efficiency and 75% fuel efficiency! We are talking about some serious fuel dollar savings when that all happens. And now, with recirculation, you are also cutting NOx by better than half as well.

Next time we will talk about how these systems do all of this.

About The Author:

Jim Roberts
President
US Ignition

Jim Roberts president at U.S. Ignition, began his 45-year career in the burner and heat recovery industry focused on heat treating specifically in 1979. He worked for and helped start up WB Combustion in Hales Corners, Wisconsin. In 1985 he joined Eclipse Engineering in Rockford, IL, specializing in heat treating-related combustion equipment/burners. Inducted into the American Gas Association’s Hall of Flame for service in training gas company field managers, Jim is a former president of MTI and has contributed to countless seminars on fuel reduction and combustion-related practices.

For more information: Contact Jim Roberts at jim@usignition.com.

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Answers in the Atmosphere: Argon Part 1 — An Inert Alternative

/ BULK GASES & SYSTEMS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, OP-ED

In this installment of Answers in the Atmosphere, David (Dave) Wolff, an independent expert focusing on industrial atmospheres for heat treat applications, explores the practical role of argon as a truly inert alternative to nitrogen in thermal processing.

This informative piece on argon’s unique properties, production challenges, and applications — from vacuum heat treating of titanium to powder metallurgy and additive manufacturing — was first released in Heat Treat Today’s February 2026 Annual Air & Atmosphere Heat Treating print edition.

Akin Malas
Business Development Manager / Metallurgist
Linde

In this column, I’ve invited Akin Malas, business development manager and metallurgist at Linde, to bring his deep expertise in the subject of argon gas. What follows is the fruit of our discussion and continued conversations about this specialized yet indispensable industrial gas in thermal processing applications.

Compared to nitrogen (the industrial gas this column last covered), argon exhibits actual inertness, enabling its use in high-temperature environments and for processing metals that cannot tolerate nitrogen atmospheres, such as titanium and certain high-performance stainless steels. While argon is significantly higher cost than nitrogen, it remains far more economical than helium, another highly inert alternative.

Argon plays a vital role across multiple stages of metal processing, including:

  • Primary metallurgy: ladle stirring
  • Powder metallurgy: atomization of metal powders
  • Additive manufacturing: laser and electron-beam processes requiring inert chamber atmospheres
  • Vacuum heat treating: backfill gas for titanium and specialty alloys

Argon is used differently than nitrogen in most cases. Inexpensive nitrogen is often used as a utility pressurization gas, for scavenging, and blended with other gases (such as hydrogen); however, argon is most often used in pure form. Nitrogen is considered inert for heat treatment applications except in extraordinarily high temperatures or heat treatment of reactive metals, such as titanium and stainless steels. In this case, using an actual inert gas like argon or helium is necessary. Also, while nitrogen is virtually the same density as air and thus will diffuse throughout a vessel, argon is much denser than air and can be used to form a stratified inert layer.

Linde gas storage tanks | Image Credit: Linde

Both argon and nitrogen are separated from air in a cryogenic air separation unit (ASU), but there are three main factors that make argon much harder to make than nitrogen and thus much more expensive:

  • Argon is only 1% of air while nitrogen is 78% of air. Argon boils at nearly the same temperature as oxygen, making a separate purification process necessary. Those two factors mean that only the largest ASUs make enough argon to make it worth purifying.
  • Argon cannot economically be separated from air non-cryogenically (primarily because the percentage in air is so low), so there is no low-cost competition to cryogenic argon. Also, because argon is prized for its inertness, there is much less interest in argon that might be lower purity.
  • Because argon is made in only the largest ASUs (typically those serving very large steel mills) and because those plants tend to be geographically grouped, shipping distances for argon tend to be much farther than for nitrogen and oxygen, further driving up the costs.

Processors of titanium parts and parts made of some stainless steels, such as the 300 series stainless alloys (SS), cannot be processed in nitrogen-containing atmospheres, because the metals will nitride at heat treating temperatures. Hence these metals may be processed in a pure argon (for Ti) or hydrogen (for SS) atmosphere blends.

We’ll pick up this discussion next month to see what market options are available, particularly in the U.S.

About The Author:

David (Dave) Wolff
Industrial Gas Professional
Wolff Engineering

Dave Wolff has over 40 years of project engineering, industrial gas generation and application engineering, marketing, and sales experience. Dave holds a degree in engineering science from Dartmouth College. Currently, he consults in the areas of industrial gas and chemical new product development and commercial introduction, as well as market development and selling practices.

For more information: Contact Dave Wolff at Wolff-eng@icloud.com.

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Ask The Heat Treat Doctor®: Why and How Do We Heat Treat Gears? Part One

/ ATMOSPHERE AIR FURNACES TECHNICAL CONTENT, CARBURIZING TECHNICAL CONTENT, HARDENING TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, NITRIDING TECHNICAL CONTENT, NITROCARBURIZING TECHNICAL CONTENT, OP-ED

Ask The Heat Treat Doctor® has returned to bring sage advice to Heat Treat Today readers, answer questions about heat treating, brazing, sintering, and other types of thermal treatments, as well as metallurgy, equipment, and process-related issues. In this installment, Dan Herring examines the essential role of heat treatment in gear performance: exploring the key material and design considerations for power transmission gears, the difference between through hardening and case hardening, and the atmosphere heat treatment processes — from carburizing and carbonitriding to nitriding and nitrocarburizing — that determine how well a gear handles load, wear, and fatigue in heavy-duty applications.

This informative piece was first released in Heat Treat Today’s February 2026 Annual Air & Atmosphere Heat Treating print edition.

Have questions or feedback? We’d love to hear from you — reach out to our editorial team at editor@heattreattoday.com.

Gears play an essential role in the performance of many products that we rely on in our everyday lives. When we think about gears, we generally separate them into two categories: motion-carrying and power transmission. Motion-carrying gears are generally nonferrous alloys or plastics, while load bearing power transmission gears (Figure 1) are usually manufactured from ferrous alloys and are intended for heavy-duty service applications.

Figure 1. Typical off-highway truck power transmission gears | Image Credit: The Heat Treat Doctor®

Gear Materials & Engineering

Power transmission gears involve a wide variety of steels and cast irons. In all gears, the choice of material must be made only after careful consideration of the performance demanded by the application end-use and total manufactured cost, taking into consideration such issues as pre- and post-machining economics.

Key design considerations require an analysis of the type of applied load, whether gradual or instantaneous, and the desired mechanical properties, such as bending fatigue strength or wear resistance — all of which will define core strength and heat treating requirements.

Figure 2. Stress profile in a heavy-duty transmission gear | Image Credit: The Heat Treat Doctor®

It is important for the designer to understand that each area in the gear tooth profile sees different service demands (Figure 2). Consideration must be given to the forces that will act on the gear teeth with tooth bending and contact stress, resistance to scoring and wear, and fatigue issues being paramount. For example, in the root area, good surface hardness and high residual compressive stress are desired to improve endurance or bending fatigue life. At the pitch diameter, a combination of high hardness and adequate subsurface strength are necessary to handle contract stress and wear and to prevent spalling.

Some of the factors that influence fatigue strength are:

  • Hardness distribution, a function of:
    • Case hardness
    • Case depth
    • Core hardness
  • Microstructure, a function of:
    • Retained austenite percentage
    • Grain size
    • Carbide size, type, and distribution
    • Non-martensitic phases
  • Defect control, a function of:
    • Residual compressive stress
    • Surface finish and geometry
    • Intergranular toughness

In the total manufacturing scheme, a synergistic relationship must exist between the material selection process, engineering design, and manufacturing (including heat treatment). A balance of the priorities in each discipline must be reached to achieve the optimization necessary for the ultimate performance of the gear design. This is often not an easy task.

Various atmosphere heat treatment methods are used for most types of gears including pre-hardening steps (e.g., annealing, normalizing, stress relief) and hardening processes (e.g., neutral hardening and case hardening).

Hardening

Neutral (aka through hardening) refers to heat treatment methods that do not produce a case. Examples of commonly through-hardened gear steels are AISI/SAE grades 1045, 4130, 4140, 4145, 4340, and 8640. It is important to note that hardness uniformity should not be assumed throughout the gear tooth. Since the outside of a gear is cooled faster than the inside, there will be a hardness gradient developed. The final hardness is dependent on the amount of carbon in the steel. The depth of hardness depends on the hardenability of the steel.

Through hardening can be performed either before or after the gear teeth are cut. When gear teeth will be cut after the part has been hardened, machinability becomes an important factor based on final hardness. The hardness is achieved by heating the material into the austenitic range, typically 815°C–875°C (1500°F–1600°F), followed by quenching and tempering.

Case Hardening

By contrast, case hardening is used to produce a hard, wear resistant case (surface layer) on top of a ductile, shock resistant interior (core). The idea behind case hardening is to keep the core of the gear tooth at a level under 40 HRC to avoid tooth breakage while hardening the outer surface to increase pitting resistance.

Carburizing

Figure 3. Atmosphere carburizing of large gears | Image Credit: Photograph courtesy of Aichelin Group

Atmosphere carburizing is the most common of the case hardening methods in use today and can handle a diverse range of part sizes and load configurations (Figure 3). In general, a properly carburized gear will be able to handle somewhere between 30–50% more load than a through-hardened gear. Examples of commonly carburized gear steels include AISI/SAE grades 1018, 4320, 5120, 8620, and 9310, as well as international grades, such as 20MnCr5, 17CrNiMo6, 18CrNiMo7-6, and 20MoCr4.

Atmosphere carburizing is typically performed in the temperature range of 870°C–955°C (1600°F–1750°F) although temperatures up to 1010°C (1800°F) are used for deep case work. Carburizing case depths can vary over a broad range, typically 0.13–8.25 mm (0.005–0.325 inches).

Carbonitriding

Carbonitriding is a modification of the carburizing process, not a form of nitriding. This modification consists of introducing ammonia into the carburizing atmosphere to add nitrogen to the carburized case as it is being produced. Examples of gear steels that are commonly carbonitrided include AISI/SAE 1018, 1117, and 12L14.

Carbonitriding is done at a lower temperature than carburizing, typically between 790°C–900°C (1450°F–1650°F), and for a shorter time. Combine this with the fact that nitrogen inhibits the diffusion of carbon, and what generally results is a shallower case than is typical for carburized parts. A carbonitrided case is usually between 0.075–0.75 mm (0.003–0.030 inches) deep.

Nitriding

Nitriding is another surface treatment process that has as its objective increasing surface hardness. One of the appeals of this process is that rapid quenching is not required, hence dimensional changes are kept to a minimum. It is not suitable for all gear applications; one of its limitations is that the extremely high surface hardness case produced has a more brittle nature than say that produced by the carburizing process. Despite this fact, in a number of applications, nitriding has proved to be a viable alternative. Examples of commonly nitrided gear steels include AISI/SAE 4140, 4150, 4340, and Nitralloy® 135M.

Nitriding is typically done in the range of 495°C–565°C (925°F–1050°F). Case depth and case hardness properties vary not only with the duration and type of nitriding being performed but also with steel composition, prior structure, and core hardness. Typically, case depths are between 0.20–0.65 mm (0.008–0.025 inches) and take from 10 to 80 hours to produce.

Nitrocarburizing (Ferritic or Austenitic)

Nitrocarburizing is a modification of nitriding, not a form of carburizing. In the process, nitrogen and carbon are simultaneously introduced into the steel while it is in a ferritic or at times an austenitic condition. A very thin “white” or “compound” layer is formed during the process, as well as an underlying “diffusion” zone. Like nitriding, rapid quenching is not required. Examples of gear steels that are commonly nitrocarburized include AISI/SAE grades 4140, 5160, 8620, and certain tool steels, such as H11 and H13.

Nitrocarburizing is normally performed at 550°C–600°C (1025°F–1110°F) and can be used to produce a 58 HRC minimum hardness, with this value increasing dependent on the base material. White layer depths range from 0.0013–0.056 mm (0.00005–0.0022 inches) with diffusion zones from 0.03–0.80 mm (0.0013–0.032 inches) being typical.

In Summary

There are many ways to heat treat gears. While atmosphere heat treatment (discussed above) is perhaps the most widely used technology today, other types of heat treatments, namely vacuum and induction hardening, are becoming more and more common methods. These will be discussed in Part Two.

About the Author

Dan Herring
“The Heat Treat Doctor”
The HERRING GROUP, Inc.

Dan Herring has been in the industry for over 50 years and has gained vast experience in fields that include materials science, engineering, metallurgy, new product research, and many other areas. He is the author of six books and over 700 technical articles.

For more information: Contact Dan at dherring@heat-treat-doctor.com.

For more information about Dan’s books: see his page at the Heat Treat Store.

Ask The Heat Treat Doctor®: Why and How Do We Heat Treat Gears? Part One Read More »

Answers in the Atmosphere: The Tremendous Value of Industrial Gas Smartphone Apps

/ BULK GASES & SYSTEMS TECHNICAL CONTENT, MANUFACTURING HEAT TREAT TECH, OP-ED

In this installment of Answers in the Atmosphere, David (Dave) Wolff, an independent expert focusing on industrial atmospheres for heat treat applications, highlights the practical value of smartphone apps designed for industrial gas calculations and conversions.

This informative piece on mobile tools that simplify gas property calculations, unit conversions, and storage or flow-rate estimations — drawing attention to apps developed by major gas suppliers and equipment providers that help heat treaters access critical data in the field — was first released in Heat Treat Today’s January 2026 Annual Technologies to Watch print edition.

The field of industrial gases is complicated by the fact that the physical characteristics of gases depend on the temperature and pressure at the time of measurement. Industrial gases may be delivered and stored as cryogenic liquids and highly pressurized gases, though they are generally used in relatively low-pressure gaseous form. Additionally, gases may be used for different purposes; for example, hydrogen may be used as a metallurgical atmosphere or as a burner fuel. As such, users need a ready source of data on various industrial gases to make necessary calculations.

Image Credit: Open Library/Internet Archive

Years ago, industrial gas users had to rely on data tables in publications like the CRC Handbook of Chemistry and Physics — the nearly 8 lb, $195 hardbound handbook that has been published continuously since 1914 and is currently on its 106th edition.

Today, there are many more mobile solutions in the form of smartphone applications. Several of the major gas providers have developed handy apps available for both Apple and Android operating systems to simplify gas conversions and calculations. Equipment providers have also developed apps to help understand the specifics of their equipment. All of these can be helpful to metals thermal processors, including heat treaters at in-house processing operations.

Some examples follow:

  • Air Products and Linde both provide powerful conversion engines that enable users to convert from imperial to metric units, from mass to volume measurements, and from liquid to gaseous volumes for common industrial gases. For example, users can calculate how many hours of atmosphere coverage 6,000 gallons of liquid hydrogen stored in a tank will provide.
  • Cyl-Tec, Inc. has developed an app that focuses on calculations primarily specific to cryogenic and pressurized gas storage. In addition to unit of measure conversions for each common industrial gas, the app provides detailed information on each of the storage vessels that the company makes.
  • WITT-Gasetechnik of Germany has developed an app to support their gas safety and controls business. Their products include gas mixers, gas analyzers, regulators, and other controls. The app provides a variety of gas blending and measurement information, including welding gas blend suggestions, unit conversion, and flow rate calculators.
  • Gasmet of Finland has developed an app that simplifies calculation of dewpoint and combustion products depending on the fuel being combusted.

While these suppliers hope that you will buy their products, be assured that the measurements and conversions performed with their tools, and the recommendations generated, will be equally applicable to products and systems supplied by others.

I suggest you create a folder called “calculations and conversions” on your smartphone and load it up with several of these apps while you are connected to your home or office internet, so that you will have the apps handy when you are away from your standard technical resources.

About The Author:

David (Dave) Wolff
Industrial Gas Professional
Wolff Engineering

Dave Wolff has over 40 years of project engineering, industrial gas generation and application engineering, marketing, and sales experience. Dave holds a degree in engineering science from Dartmouth College. Currently, he consults in the areas of industrial gas and chemical new product development and commercial introduction, as well as market development and selling practices.

For more information: Contact Dave Wolff at Wolff-eng@icloud.com.

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