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Low Temperature Surface Carburization of Stainless Steels. (Final Report, January 1, 2004-December 31, 2006).

DE2008920895

Publication Date	2007
Personal Author	Collins, S. R.; Heuer, A. H.; Sikka, V. K.
Page Count	119
Abstract	Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces.
Keywords	Surface hardening Carburization Steels Low temperature Carbides Austenitic stainless steels Thermodynamics Models Corrosion resistance Wear resistance Fatigue Ductility Diffusion Mobility Surface treatments Metals Alloys Crystals Dimensions Low temperature colossal supersaturation(LTCSS)
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Oak Ridge National Lab., TN.; Case Western Reserve Univ., Cleveland, OH.; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Case Western Reserve Univ., Cleveland, OH. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200811

Low Temperature Surface Carburization of Stainless Steels. (Final Report, January 1, 2004-December 31, 2006).

Low Temperature Surface Carburization of Stainless Steels. (Final Report, January 1, 2004-December 31, 2006).
DE2008920895

Publication Date	2007
Personal Author	Collins, S. R.; Heuer, A. H.; Sikka, V. K.
Page Count	119
Abstract	Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces.
Keywords	Surface hardening Carburization Steels Low temperature Carbides Austenitic stainless steels Thermodynamics Models Corrosion resistance Wear resistance Fatigue Ductility Diffusion Mobility Surface treatments Metals Alloys Crystals Dimensions Low temperature colossal supersaturation(LTCSS)
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Oak Ridge National Lab., TN.; Case Western Reserve Univ., Cleveland, OH.; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Case Western Reserve Univ., Cleveland, OH. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200811