A-2 Heat Treat ?

Jack O'Neill

Jack O'Neill

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Nov 15, 2007
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I believe I have most of it down . 1775 -1825 degrees , a 20 minute soak,a double temper at 400 degrees .

A well respected heat treater says to cyro after the 1st. temper . I also read last night that the temper should be done right after the plate quench . So is there a brittleness issue with the A-2 which requires a quick temper before the cyro soak ?

How do you folks do the A-2 ?

Thanks for any input you can give me .
Jack ONeill
 
Lots of guys are going straight from quench to cryo, if you temper first it should be short and at relatively low temp, is what I have been able to learn.
I would also stick with the lower end of the austenizing range.
 
from what I have read , cyro being part of the quench is for the stainless steels . A-2 is not considered a stainless , which leads me to the question above . Maybe a snap temper to be on the safe side .

No other input , I'm feeling rejected :(
 
Jack I've not done any A2,but I go straight to cryo after plate quench with all the air hardening steel I do.The reason is to convert RA and if you tenper first you stabilize some of the RA and it won't convert.
Stan
 
thanks Stan . I understand the conversion of the RA and cyro , but Paul Bos had mentioned to me about the cyro for A-2 being done between the temper cycles to avoid a cracked blade . I was hoping that those who do there own HT of A-2 would join in here with some info .
 
Put blades in at room temperature

ramp up to 1500'F (as fast as your kiln will go)

Hold for 30 minutes

then ramp up to 1800'F

Hot for 40 minutes

Open the door and take out the SS foil packets

Leave on garage floor till all visible red heat is gone

open packet with scissors, check for straightness,

straighten if necessary

hang up blade to still air quench.

comes out at 65-66 RC

Wait till it cools down to room temperature

Temper @ 500'F for 2 hours

Cool to room temperature between tempering cycles

RC 60-61

(I have two kilns, so the snap temper is not needed)

I have left blades to cool overnight and tempered in the
morning. Have never had a problem with cracking or any
issues whatsoever.

Personally I don't like plate quenching because it can
cause undesired issues and find that still air quench
doesn't stress the steel to death so quickly as plate
quenching does. But that's just me.
 
I do air quench(still air) than cryo, than temper at 400-500F depending on desirable hardness.
Did have cracks few times when cryoed too quickly(dropped the blade in LN2).
 
Thanks guys and thanks Leu for typing all that out . I'll take all input I can get .
 
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