N60 W15088 Bobolink Ave. --  Menomonee Falls, WI 53051 -- (262) 252-3804 / 800-366-1973 - Email Badger Metal Tech

Javascript DHTML Drop Down Menu Powered by dhtml-menu-builder.com

History of Nitriding

The early pioneering work of Fry, Machlet, as well as others

Dr. Adolph Fry in the early 1900's found that nitrogen and iron had an affinity to one another, much the same way that aluminum and iron contact under heat can cause soldering to occur in die casting dies.
From his work in 1906 he developed the iron-nitrogen equilibrium diagram.  This diagram is still valid today.  If heat is applied to both iron and a nitrogen gas, the nitrogen will diffuse in the surface of the steel and along with this create a structural change in the surface of the steel affecting the hardness.  This increase, it was noted, went from 282 Brinell hardness to 470 Brinell in steel containing .39% carbon and 2.88 % chromium.
From this began the development of extremely high surface hardness steels called "Nitralloy" steels.  These steels provided high resistance to decomposition along with being stable to temperatures up to 1800 degrees F.
Dr. Fry also investigated the effect of adding other alloys such as vanadium, tungsten, manganese, molybdenum, and titanium and discovered that all of these elements would also produce stable high nitrogen content nitrides.

At the same time in New Jersey, Adolph Machlet while working for American Gas Company in Elizabeth, was also studying absorption of nitrogen into iron under heat conditions.  He applied for his patents somewhat earlier than Fry.  He consequently received his patent long before Fry on June 24, 1913.  Sad to say no commercial benefits were recognized by US industries at the time, however, Dr. Jeffries in Essen Germany saw otherwise and pushed for America to further develop it.

In 1927 at an SME convention in Chicago a good friend of Fry, Pierre Aubert presented both the research and practical applications for it that were being used in Europe.  These included, railway steel, machine tools, along with other applications in both the auto and aviation industries.  Here are some of the benefits explained at the time:

• High surface hardness with practically no distortion
• Core material properites did not change
• Higher wear resistance than those acheived at the time with other surface treatments
• Tempering did not negate the hardness advantages
• No shelf life aging since parts were free of internal stress
• Corrosion resistance

These benefits still hold true today, however, the techniques for creating the diffusion have advanced and improved.

Work continued and in 1928, McQuaid and Ketchum both metallurgists at Timken - Detroit Axle Co. presented yet another paper using the work of Fry and Machlet as their pivot point along with some of their own investigative work into practical applications and costs.

Next in 1929, Robert Sergeson from Central Alloy Steel Corp. in Canton, Ohio did work that was published with regard to the effect of varying the aluminum content of the nitralloy along with the effect of nickel.

It was not until V.O. Homberg and J.P. Walsted at MIT that any work was done on the effect of varied temperature on the physical properties of the nitriding steels, equipment preheat-treatment, and decarburization effects on nitrided steel.  In their work, the initial comments were made regarding the phenomena of "white layer" and its effects on component performance.

Dr. Carl F. Floe an Associate Professor at MIT continued the study of the "white layer" (epsilon) effect and supported discussions of various methods to change the composition and reducing or changing this thin hard layer.  His work today is known as the "The Floe Process".

All of this early pioneering work in the field of nitriding ranging from process control, evaluation of metallurgical results, alloy steel developments, and most others still are gospel in today's processing environments.

This early work led the way for the 1930 Plasma Ion Nitriding or "Glow Discharge Technique" as it is also known.  The jump start for this technology was the desire to be able to shorten cycle times, reduce distortion and improve upon the metallurgical problems and properties associated with nitriding.

Continuing development, refinement, and modern day capabilities have progressed carbonitriding from the early liquid, gas, and plasma to controlled atmosphere methods.  Now in the early 21st Century comes automated ferritic nitrocarburizing.  We are proud to be the first company in the United States to offer TherMaLLifeÒ for the perishable tooling industry.

back to topics