ATS 34 oil quench or not??????

[MoblMec]

Hi Guys
I have made several knives out of ats 34 and my heat treat guy air hardens them between alum. plates just like 440c.
Now I am ordering some ats34 from Admiral Steel and read they say to oil quench it.
Whats the right way and will it make a diffrence?
My guy gets a 60-61 RC with air cooling.
Don't know what to do?
Thanks
MoblMec

 

[Doug Lester]

When the data sheets are formulated they are generally talking about bars of steel that are about an inch thick and regular in shape, possibly round. Knives are different animals. They are thin enough that there is little difference between the cooling rates of the surface and core of the blades. They also qualify as irregularly shaped objects that will cool more quickly in the thinner parts than the thicker parts and form conversion products of austinite at different rates which can do nasty things to steel to have martensite form in the edge while the spine is still austenetic. I would go with the slowest quenchant that will adequately harden the steel. In this case air.

Doug

 

[Knifemaker.ca]

I agree with Doug - perhaps for a different reason. Plate quenching ATS34 should be very clean and yeild full hardness - 63 - 64 before tempering if cryo'd. Oil quench will also work fine, but with all the mess and cleanup, why would anyone want to? Your heat treater has it right.