time limit between quench & cyro

[Jack O'Neill]

quick question , using the air harden steels . Do the blades need to be soaked immediately after the H.T.and plate quench or can they sit for a day or 2 before soak and then temper ??

 

[silver_pilate]

My understanding is that after too much time, a portion of the retained austenite stabilizes and cannont be converted with cryo or temper.

I'd imagine you may see some difference/benefit with cryo after 1-2 days (just a guess), but not as much as you could. I always go straight into the liquid nitrogen after the blade has reached room temperature from the quench plates. I've never done a snap temper (working with 440C, ATS34, and CPM154), and I've never had a blade break doing cryo.

--nathan

 

[SBuzek]

I'm with Nathan
I plate quench then into the cryo tank overnite and temper the next day.
Stan

 

[galadduin]

Waiting after quench or snap tempering stabilizes a portion of retained austenite that cannot be converted to martensite with cryo...
Emre

 

[Stacy E. Apelt - Bladesmith]

Agreed with all the above.

The cryo is just the bottom of the Mf. Make a graph of your HT.If you don't go to cryo, and reach Mf, in a more of less continual line, then you haven't finished the quench. A similar comparison is holding many steels at about 200 degrees above Mf (about 400F for simple carbon steels, and room temp for cryo type steels),for one to two days.The simple steel turns into bainite. Stopping the quench at room temp for high RA steels isn't quite that dramatically different, but you see where I am going. It is best to get to -100F or lower in one straight drop.
Stacy

 

[kc custom]

As part of the quench, for me its in front of a blower (in the foil),cut open as
quickly as possible, plates till ambient, then dry ice and alcohol or suspend over
the LN. I to agree with all of the above get the blades cold as quick as possible.
Ken.

 

[Jack O'Neill]

thanks guys for the info and input . I'm toying with the thought of doing my own H.T. on the ATS and A-2 I use .