Cryogenic treatment of steel

[EVM]

Hello) I work with steel 12X18H10T after cryogenic treatment and subsequent anneal uniaxial tension. Have you encountered similar steels and what research method apply?

[Enthalpy]

Hi EVM!

 

Never encountered the name before because it's a Russian designation, apparently for plain X12CrNiTi18-10, among the most common austenic stainless steel:

http://www.steel-grades.com/Steel-Grades/Heat-Resistant-Steel/12x18h10t.html

 

EN equivalents would have a bit less carbon, like <0.06% in X6CrNiTi18-10, which improves the corrosion behaviour of weld seams. The "temper" and "HRC" data is the previous link look nonsense.

 

I can't help more...

- I don't see a reason for cryo with this steel. Other stainless (PH15-7 maybe?) use cold to finish the martensitic transformation. Some benefit from cold to obtain work hardening using smaller deformations, typically to make rocket tanks, but CrNi17-7 would be better than 18-10 and is preferred then.

- On annealing, the CrNi18-10 family uses to forget all previous treatments, so why use cold before?

- I don't understand "what research method applies"

- You could look at the websites of Carpenter, Boehler, Allegheny... They often explain much about the heat response of their alloys. Search for 18-10 alloys with titanium and without molybdenum.

[Enthalpy]

Maybe you could detail more in which sequence cold, tension and annealing are applied, and what the conditions are?

 

For instance, anealing CrNi17-7 at 700°C suppresses the hardening benefit of previous cold-rolling, but tempering at +200°C makes it more resilient AND improves the yield strength a bit.

 

I can't tell if the Russian Gost make a difference between CrNi18-10 and 17-7. Anyway, some suppliers do cold-work even the CrNiMo18-12, despite it hardens less quickly; for instance Bulten prefer this alloy for their screws (originally for submarines), which are non-magnetic and resist seawater corrosion.