Quenching gas for PH stainless steels

[skailup]

Hi experts,

In vacuum heat treating of 17-4 or 13-8, what are common quenching gases? Specifically, would nitrogen cause any concern if used in solution treatment (1900 F) and in aging (H1150 or lower)? For thick section (3-in), is argon adequate or do I need helium?

Thank you,
skaiup

 

[TVP]

Nitrogen is often used. Argon or helium may also be used.

http://www.vacaero.com/Vacuum-Heat-...art-1-markets-processes-and-applications.html

 

[EdStainless]

It is more important to cool low enough, quench rate isn't too critical.
Various sources say that you have to cool below 90F or 80F. The actual temp for full transformation depends on composition and it can vary from 120F to 80F.
For thick sections often you will furnace quench and then have to pull the parts and put them into cold water to finish the transformation.

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[skailup]

Thank you very much!

 

[EdStainless]

You should make sure that you can get the entire part (clear through) below 90F within 2 hours of starting the cooling process (though I would be happier with faster).

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