Unable to temper after main quench

Shaw Blades

Shaw Blades

Joined
May 18, 2009
Messages
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A fellow knifemaker on here helps me heat treat my knives and he lives about 1.5 hours away. So I have been doing batches, heat treating them at his place, then driving home and tempering them. Am I losing out on something by not being able to temper immediately after the main quench? All of my reading about heat treating is making me think I really might be.....

Can someone help me out?
 
It all depends on what the steel is. Some, like 1080, 1084, O1 can be tempered later (although not recommended), but steels such as W2 and 1095 need a temper just as soon as humanly possible - i.e. wipe the oil off while you're on your way to the already heated oven.
 
It will depend on a lot of variables. If you are doing a typical austenization cycle and oil quench with an oil or water hardening steel, it's probably not that critical to temper immediately. If you are using a racy heat treat, multiple quenches, water quench and/or a more complex alloy then your chances for trouble increase.
 
It's a really good idea to do a snap temper as soon as possible, especially if you get into higher carbon (e.g. 1095, W2, O1).
The snap temper can be at a much lower temperature than your final temper, but just an hour at, say, 350 F would help
a lot. This will relieve the worst quenching stresses.

NB: My main experience is with O1 and A2, where the final temper is 425-500 so 350 is low. Make sure it's low
for your steel choice.
 
Even 1095 and W2 should be allowed to cool down to 130F or so before tempering in order to get as much martensite conversion as you can. Racing to the tempering oven too soon could cut yourself short. After I do an interrupted quench, I put the blades back into the oil until my oven is ready to temper. It usually takes a couple hours but my steel is still warm in the oil.

I can't speak for the guys who clay/edge quench.
 
Sounds like I might not be in bad shape if I rush straight home then. I can have the oven ready to go by the time I get back. Thanks everyone.
 
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