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- Mar 15, 1999
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Cryogenics for Sharper edges
Copyrighted Advisor In Metals, Bill Bryson March 1999
Approximately 150 years ago, Swiss watchmakers were burying certain watch parts in snow banks during the long Swiss winter months to improve wear and accuracy. During the 1930, and 1940s it is well documented at many shipyards, sub zero cold was known to remove stresses in welded joints. Toolmakers, in the 40s, remember storing their tool steels in deep freezers for months to gain a little more wear resistance and stabilize their tools. They had no idea why there was improvement, but they knew something was happening.
In the late 1970s and early 1980s, cryogenics for wear resistance started to get some more attention and new processing companies were born to perform these services. But these companies were on their own. There was no guide book to point the way.
People are a little better informed about the benefits of cryogenics today, but theres still a long way to go in getting people up to speed on what it does, why it does it, and what they need to do to make it work better. Having worked with cryogenics and studying it from a metallurgical aspect, taught it and performed it since the mid 1960s, I dont have all the answers but am confident of even better technology refinement in the future.
The process can dramatically reduce consumption of perishable tools, both High Speed Steel and Carbide. It can substantially reduce machine down time attributable to tool or part replacement. No decarburization takes place, future grain growth and dimensional changes are eliminated, stress can be eliminated, and there is no discoloration of the metal. Cryogenics is also used to toughen and stress relieve nonferrous metals and some plastics. It causes the crystal structure to realign and form a denser structure with closely knit molecules that creates a change in the strength and toughness of metals or plastics.
As for wear resistance; martensite is the fine grained structure that is transformed from austenite during the quench cycle in heat treating ferrous metals. It is the desirable, fine grain structure that should be found in all heat treated steel. Austenite refers to the grain structure that forms during the austenization temperature soak and resists complete transformation when quenched. There is no method within the heat treating process to obtain complete transformation of austenite to martensite. Typically, 70% or less martensite is made available with even GOOD heat treating practices, and many tools will run well below 50% martensite transformation. The cryogenic process completes the transformation to near 99.9% every time. Much of the wear resistance gain is the result of additional carbide precipitation into very fine carbides producing superior wear gains in tools.
So what does it do for knives? Cryogenically treating a knife has several desirable attributes:
First, WEAR RESISTANCE! When cryogenics is performed on a knife, there is a completion of the heat treating process to transform the retained austenite into martensite. This creates a nice fine grain structure, but the real gain to wear is an offshoot of that process. The iron carbon combination precipitates carbides in an extremely small and fine configuration. It is really these carbides that double, triple or multiple by many times the wear resistance in ferrous metals.
Second, KEENER CUTTING EDGES! There is a realignment of molecules to close (densify) and reorganize the grain structure during cryogenics. The surface of the metal actually becomes smoother by the elimination or reduction in the surface peaks and valleys. This smoothing action can be seen on the cutting edge of the blade.
Lastly, STRENGTH! The denser microstructure increases the strength of a metal. Through the closer packed and more uniform grain structure, it produces an increased toughness. The Rockwell hardness does not increase, unless the heat treat process is wrong. If the time or temperature is not correct, larger amounts of austenite are formed. If this happens there often is a softening in the hardness. Cryogenics will remedy this problem and the blade hardness will snap right back into hardness more consistent to where it should be.
After we cryogenically treat blades or tools, we perform a mild tempering to make sure the freshly created martensite is tempered and not brittle. This process doesnt change the materials workability. The grinding is no different after treatment.
Cryogenics is the newest technology available to dramatically increase the productive life of thousands of products. It is a one time, permanent treatment for ferrous metals for wear resistance. The process has a profound effect on molecular and crystal structure in nearly every known material. This change effects life, wear and molecular strength.
If you have a question about cryogenics or simply want to discuss your application, feel free to contact us.
The typical cost for processing a knife is:
0 to under 6 ..$5.00
6 to under 12 $10.00
12 to under 24 ..$15.00
24 to under 36 ..$25.00
Blades should be packed to avoid damage and payment should include cost of return shipping plus insurance.
The author, Bill Bryson, Advisor In Metals, has taught seminars and has a video series on heat treatment, cryogenics and basic metallurgy for 20+ years to over 240 industries, schools, SME and ASM groups. He has written Heat Treating, Selection and Application of TOOL STEELS, published by Hanser Gardner Publications, and recently completed a new book Cryogenics, Put The Freeze On Wear being released this spring. He is on the ASM sub committee for Cryogenics and recently spoke on the subject at the ASM convention in Chicago. Advisor In Metals offers cryogenic processing for knives and tools. You may contact him at Advisor In Metals, RR1 Box 4243, Union, NH 03887 or hisaim@worldpath.net
Copyrighted Advisor In Metals, Bill Bryson March 1999
Approximately 150 years ago, Swiss watchmakers were burying certain watch parts in snow banks during the long Swiss winter months to improve wear and accuracy. During the 1930, and 1940s it is well documented at many shipyards, sub zero cold was known to remove stresses in welded joints. Toolmakers, in the 40s, remember storing their tool steels in deep freezers for months to gain a little more wear resistance and stabilize their tools. They had no idea why there was improvement, but they knew something was happening.
In the late 1970s and early 1980s, cryogenics for wear resistance started to get some more attention and new processing companies were born to perform these services. But these companies were on their own. There was no guide book to point the way.
People are a little better informed about the benefits of cryogenics today, but theres still a long way to go in getting people up to speed on what it does, why it does it, and what they need to do to make it work better. Having worked with cryogenics and studying it from a metallurgical aspect, taught it and performed it since the mid 1960s, I dont have all the answers but am confident of even better technology refinement in the future.
The process can dramatically reduce consumption of perishable tools, both High Speed Steel and Carbide. It can substantially reduce machine down time attributable to tool or part replacement. No decarburization takes place, future grain growth and dimensional changes are eliminated, stress can be eliminated, and there is no discoloration of the metal. Cryogenics is also used to toughen and stress relieve nonferrous metals and some plastics. It causes the crystal structure to realign and form a denser structure with closely knit molecules that creates a change in the strength and toughness of metals or plastics.
As for wear resistance; martensite is the fine grained structure that is transformed from austenite during the quench cycle in heat treating ferrous metals. It is the desirable, fine grain structure that should be found in all heat treated steel. Austenite refers to the grain structure that forms during the austenization temperature soak and resists complete transformation when quenched. There is no method within the heat treating process to obtain complete transformation of austenite to martensite. Typically, 70% or less martensite is made available with even GOOD heat treating practices, and many tools will run well below 50% martensite transformation. The cryogenic process completes the transformation to near 99.9% every time. Much of the wear resistance gain is the result of additional carbide precipitation into very fine carbides producing superior wear gains in tools.
So what does it do for knives? Cryogenically treating a knife has several desirable attributes:
First, WEAR RESISTANCE! When cryogenics is performed on a knife, there is a completion of the heat treating process to transform the retained austenite into martensite. This creates a nice fine grain structure, but the real gain to wear is an offshoot of that process. The iron carbon combination precipitates carbides in an extremely small and fine configuration. It is really these carbides that double, triple or multiple by many times the wear resistance in ferrous metals.
Second, KEENER CUTTING EDGES! There is a realignment of molecules to close (densify) and reorganize the grain structure during cryogenics. The surface of the metal actually becomes smoother by the elimination or reduction in the surface peaks and valleys. This smoothing action can be seen on the cutting edge of the blade.
Lastly, STRENGTH! The denser microstructure increases the strength of a metal. Through the closer packed and more uniform grain structure, it produces an increased toughness. The Rockwell hardness does not increase, unless the heat treat process is wrong. If the time or temperature is not correct, larger amounts of austenite are formed. If this happens there often is a softening in the hardness. Cryogenics will remedy this problem and the blade hardness will snap right back into hardness more consistent to where it should be.
After we cryogenically treat blades or tools, we perform a mild tempering to make sure the freshly created martensite is tempered and not brittle. This process doesnt change the materials workability. The grinding is no different after treatment.
Cryogenics is the newest technology available to dramatically increase the productive life of thousands of products. It is a one time, permanent treatment for ferrous metals for wear resistance. The process has a profound effect on molecular and crystal structure in nearly every known material. This change effects life, wear and molecular strength.
If you have a question about cryogenics or simply want to discuss your application, feel free to contact us.
The typical cost for processing a knife is:
0 to under 6 ..$5.00
6 to under 12 $10.00
12 to under 24 ..$15.00
24 to under 36 ..$25.00
Blades should be packed to avoid damage and payment should include cost of return shipping plus insurance.
The author, Bill Bryson, Advisor In Metals, has taught seminars and has a video series on heat treatment, cryogenics and basic metallurgy for 20+ years to over 240 industries, schools, SME and ASM groups. He has written Heat Treating, Selection and Application of TOOL STEELS, published by Hanser Gardner Publications, and recently completed a new book Cryogenics, Put The Freeze On Wear being released this spring. He is on the ASM sub committee for Cryogenics and recently spoke on the subject at the ASM convention in Chicago. Advisor In Metals offers cryogenic processing for knives and tools. You may contact him at Advisor In Metals, RR1 Box 4243, Union, NH 03887 or hisaim@worldpath.net
