Gas-Metal Interactions
October 2012 | Issue 22

MetalTech: A new approach to nitriding of low-alloy steels

Issue: production variability

New burner to increase yield for secondary aluminum melters

Ask the expert

Ready. Set. Convert.

Meet this issue’s metal head

Where to find us

Useful Web links

Contact us

metals and money

Metals and money
For accurate forecasting and planning, it helps to understand the movement of key industry indices. Air Products’ economists have compiled the following graphs for you to illustrate three-year trends for utility and metals pricing as well as industrial production. We’ll continue to keep you updated in future issues.

industrial production indexes
Industrial Production Indexes
Source: U.S. Federal Reserve Bank Board of Governors
View graph →

utility pricing metrics
Utility Pricing Metrics
Source: Inside F.E.R.C., Bureau of Labor Statistics
View graph →

steel prices
Steel Prices

Source: Market Pricing
View graph →

key metals prices
Key Metals Prices

Source: London Metals Exchange
View graph →

Quotes & Quips
“Effort only fully releases its reward after a person refuses to quit.”
— Napoleon Hill
MetalTech: A new approach to nitriding of
low-alloy steels

Zbigniew Zurecki
Conventional, ferritic nitriding of low-alloy steels is a surface hardening treatment that can take many hours and, sometimes, days. Its temperature is limited to below the critical, eutectoidal temperature in order to minimize dimensional distortions. Subcritical-temperature austenitic nitriding can be an alternative to the conventional process in certain applications. It involves nitriding at increased temperatures, forming a micro-thin layer of nitrogen-austenite under the steel surface, accelerated cooling, and cryogenic nitrogen aging.

Zbigniew Zurecki, Senior Research Associate at Air Products, and scientists from the Center for Heat Treating Excellence at Worcester Polytechnic Institute evaluated this alternative process with the purpose of accelerating nitriding treatment, bringing energy savings, and improving toughness of nitrided layers while minimizing thermal distortion of treated parts. They tested AISI 4140 steels—examining the interplay between the nitriding and cooling conditions and phase transformations in the conventional, ferritic (525°C or 980°F) and the subcritical, austenitic (610°C or 1130°F) treatments. Additionally, they applied thermodynamic models for process design and microstructural interpretation of resultant layers, examined through SEM, EPMA and EDS.

To learn about the results of these experiments, treatment rates, and dimensional changes of nitrided parts, read their white paper, “Thermodynamic model-assisted evaluation of phase transformations in subcritical austenitic nitriding.”

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Issue: production variability

Recently, a rolling mill facility contacted Air Products because they could not pinpoint what was causing production variability in their annealing furnace. Process variability in furnaces using a protective atmosphere can be caused by many factors. The purity of the inlet gases is one factor which is frequently questioned by our customers. Although, it is usually not an issue, it should never be ruled out without testing. To find out how Air Products helped the customer accurately profile their furnace and determine the sources of production variability, read the full article.

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New burner to increase yield for secondary aluminum melters

new burner to increase yield for secondary aluminum melters
The new Air Products High-Yield Oxy-fuel Burner was designed specifically to increase yield for secondary aluminum melters. Our patent pending* burner technology minimizes melt losses and flux usage while achieving improved productivity, reduced process costs and emissions. Our High-Yield Oxy-fuel Burner can provide the same benefits of conventional oxy-fuel technology, including fuel savings, increased production, and reduced baghouse temperatures and loadings, as well as yield improvements through reduced melt times, reduced free oxygen, and more consistent operation.

* US2011 0154950 A1

Check out our data sheet to learn more about the benefits you could realize with our High-Yield Burner, as well as comparison results from tests with conventional oxy-fuel technology.

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Ask the expert: Anna Wehr-Aukland, Ph.D.
Senior Principal Research Chemist

ask the expert - Anna Wehr-Aukland
Q: What’s the best approach to select the hydrogen concentration for our nitrogen-hydrogen atmosphere for bright annealing of steels?

A: You can use the Ellingham diagram to predict the conditions that will be reducing to iron oxides and the oxides of the alloying elements added to steels. Alternatively, you can use more accurate and convenient diagrams for steels that were calculated using modern databases and computer programs. These techniques will help you troubleshoot and optimize your annealing operation by balancing hydrogen usage versus product quality. To learn more about these methods, read Anna’s full answer.

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Ready. Set. Convert.

gas converter app
Introducing the Air Products Gas Converter. Our new app converts weight and volume measures for industrial gases like nitrogen, oxygen, argon, hydrogen, helium, and carbon dioxide, as well as liquefied natural gas (LNG/methane), easily and quickly, right from your iPhone® or iPad®. And it’s free!

When converting between liquid and gaseous units, the converter accounts for the unique properties of each industrial gas, particularly molecular weight and density. For LNG, it converts flow rates, including Diesel Gallon Equivalents (DGE), and allows you to specify values for a number of variables.

Make your life simpler. Download the Gas Converter app today at

Meet this issue’s metal head: Shailesh Gangoli
Flow Architecture

Shailesh Gangoli
Like any young child, Shailesh Gangoli, dreamed of what he would be when he grew up. He loved visualizing and sketching buildings and thought maybe he would have a career as an architect. Then he found he also loved trains and anything that moved, and built on this passion by obtaining an undergraduate degree in mechanical engineering from Manipal Institute of Technology in India and a doctorate from Drexel University, specializing in plasma technology.

Today, as a Principal Research Engineer in Air Products’ Combustion R&D Group, Shailesh spends his time visualizing not buildings, but rather the mixing of flows, as he develops oxy-fuel burner technologies that produce the best flow patterns to achieve different energy releases for the right applications. Working with customers all over the world, he notes that the metals industry is regionally very different, depending on not only the type of metal, but also the furnaces employed, processes used, and the specific drivers for the business.

“There is no ‘cookie cutter’ approach and I enjoy working with our Commercial Technology group to develop a custom designed solution to fit our customer’s individual needs” notes Dr. Gangoli, adding that for him the following old saying is very true, “If you really enjoy what you do, you’ll never work another day in your life.”

Where to find us

Fabtech 2012—November 12–14, 2012
Las Vegas, NV; Booth C3814
Fabtech website →

TMS—March 3–7, 2013
San Antonio, TX
TMS website →

Forge Fair—March 26–28, 2013
Columbus, OH
Forge Fair website →

CastExpo 2013—April 6–9, 2013
St. Louis, MO; Booth 3047
CastExpo website →

ISRI—April 9–13, 2013
Orlando, FL
ISRI website →

AISTech 2013—May 6–9, 2013
Pittsburgh, PA; Booth 434
AISTech website →

PowderMet 2013—June 24–27, 2013
Chicago, IL; Booth 310
PowderMet website →

Useful Web links

The Aluminum Association, Inc.
American Foundry Society (AFS)
American Welding Society
ASM Heat Treating Society
ASM International, Society
Association for Iron & Steel Technology (AIST)
Industrial Heating, International Journal
International Thermal Spray Association
Metal Powder Industries Federation
Metal Treating Institute
The Minerals, Metals & Materials Society (TMS)
Pennsylvania State University – Center for Innovative Sintered Products
Worcester Polytechnic Institute – Center for Heat Treating Excellence

Contact Us

You can request more information or any of the documents referenced in this issue by calling us at 800-654-4567, code 936, or by contacting us online.

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Legal Notice | © Air Products and Chemicals, Inc. 2012 330-12-027.2-US

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