Heat treat question????

J

jsmithknives

Joined
Dec 11, 2008
Messages
393
I need a little help on some heat treating I am doing! I am using a coal fire to heat treat some 5160 and quenching in parks 50.
Here is the problem I am having, after I have the blade to nonmagnetic I let it soak for another two minutes then I am quenching in the oil which is heated to 125 degrees, the problem I am having is the blade is warping in the quench. I am dunking the blade tip first in the oil and dunking it fast but I am not sure how to correct the problem!
If the warp is normal then how or when to I attempt to bend the blade back straight. I have done this whole process before and never had a problem, so I really can't figure out what I am doing wrong.
Thanks in advance for all of your help!!!
Jason
 
I can answer part of your question. The best time to straighten is during the quench, after it has fallen below 600 degrees, but before martensite is fully formed. After about 7 to 10 seconds you can pull it from the oil. It should be steaming hot, around 500. You're under the nose so you can take your sweet time and it will be like taffy until it gets under about 300. Once it starts to "set up", stop.

Warping can be caused by a lot of things, including too thin, uneven heat, swishing the blade in the oil side to side instead of up and down and front to back, lack of normalizing, stress from grinding. I'll let someone more knowledgeable answer that one
 
Hay Jason, What I do is -quince until the count of 10 -pull the blade out and quickly put it in the plates and clamp it tight. Jerry
 
I was not sure of how long to leave the blade in the oil, so this gives me the answer I was looking for to be able to pull the blade out after 7 to 10 seconds then reshape to straight!!!
Thanks for your help, I will give this a try!!!
 
What's the temp of that blade during your two minute soak?
How are you controling, not only an even temp throughout the length of the blade, but a consistant temperature of the coal as well?
 
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