English-speaking countries refer to steel alloys that contain greater than ~ 10.5% chromium as "stainless steels". I am unclear what you mean by "mechaniced", however you need to provide additional information regarding the type of stainless steel you are using. Austenitic? Ferritic? Martensitic? Precipitation Hardening? If you have the chemical composition and/or specification (ASTM, EN, SAE, etc.) that would also be helpful.
Austenitic stainless steels attain full stress relief at a temperature of ~ 900 C-- 870 C results in only partial stress relief. Best results occur when using slow cooling, but care must be taken with respect to sensitization.
Conventional ferritic stainless steels (Types 405, 409, 430, etc.) have a wide range of stress relieving temperatures-- from 650 C to 925 C, depending on the alloy composition. Various forms of embrittlement can occur in these alloys. Low-interstitial ferritic alloys may require higher temperatures-- 760 C to 1065 C, again depending on the alloy composition.
Duplex alloys are annealed/stress-relieved in the temperature range of 925-955 C for Type 329 up to 1065-1175 C for higher alloyed grades like Ferralium 255.
Martensitic alloys that have been hardened should be stress relieved between 150-370 C.
I do not want to make any statements on the precipitation hardening grades as an entire category. If you are interested in more information, the material suppliers for these grades will definitely have this type of data available.
If you are interested in more information I suggest you investigate some of the following:
ASM HANDBOOK Volume 4 Heat Treating available from ASM International
