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"How to obtain RH950 Condition"
January 11, 2010
It is necessary to perform cryogenic treatment (-730C) to reach RH950 Condition? As known, this step only completes the martensite transformation.
And why this step relatively is so long?
CH Condition means (Cold Worked). What about R and T meanings?
Materials Engineer - Israel
January 14, 2010
You're talking about the semi-austenitic precipitation hardening stainless steels, such as 17-7 and 15-7. These are not fully martensitic after solution treating, and need additional "pushing" to fully transform. Hence you either cold work the material, to get to condition C, or you give it an austenite conditioning step which will cause full transformation to martensite. The R and the T treatments are two that are recognized as successful, and are documented in heat treat specifications such as AMS 2759/3 or Mil-H-6875.
You'd likely benefit from reading DMIC report 111, from April 1959, on "The Physical Metallurgy of Precipitation Hardening Stainless Steels". Send me an e-mail and I'll send you a copy. I'm not that hard to find...
metallurgist - E. Aurora, New York