Cryogenic Treatment of Materials

[weed78]

I tried this posting in the Cryogenic Engineering forum but received no replies so I will ask my question here.

Is there a significant difference in the final wear properties of tool steel materials cryogenically treated in liquid vs vapor?

 

[Goahead]

You probably mean the Subzero treatment used to transform retained austenite (obtained upon quenching in oil or in air) into martensite (to be subsequently tempered) in order to increase the hardness of the steel.
What matters is the temperature.
You might use dry ice (frozen carbon dioxide) at -78.5 C or
liquid nitrogen at -196 C.
It depends on the amount of austenite present and on its stabilization, that may make it harder to transform.

http://www.welding-advisers.com/

 

[alexit]

We usually triple cryo for our machine tool parts. This is to reduce distortions for later temperature variations. I have never seen any part in contact with the liquid nitrogen, the tray is suspended in the boiling zone and heat is removed there. Recently we began qualification of an in-house cryo at -100°C, becuase this is the lowest temperature our freezer can maintain...