5160 tempering

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Nov 17, 2007
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I’ve done a few tests with tempering cycles and temperature settings with 5160. My test peices are forged from 1/4" to 1/8", annealed, ground down to rough shape, normalized three times, hardened, tempered then hand sharpened. I tempered six pieces two each at 375deg at 1.5hours, 1.5hoursX2and 1hourX3. I tempered six more at 400deg at the same time cycles as before. Two I tempered at 450 for 2 hours and one I did not temper at all for a starting point to test against. I tested all the edges by the brass rod method. The pieces tempered at 450 for 2 hours were too soft, the edge rolled. The one that wasn't tempered chipped as expected. All the other tempered pieces seemed to act the same except the ones at 375deg for 1.5hours, they did not chip but it seemed the edges did not flex hardly at all. I also put all pieces in a vise and bent them until they snapped. The ones that weren’t tempered snapped with ease as expected, all others snapped with what seemed like the same pressure including the ones at 450degs which was roughly three times the pressure as the ones that wasn't tempered. I know these aren't exactly the best way to test but i was trying not to rely on you guys so much but I thought I'd see more of a difference in the temper cycles than I saw. So it leads me to my questions:

What is the best temperature and time cycles to treat 5160?

Are they a temper color chart for 5160 on the web somewhere?

What color do you guys draw the spine to? And since it’s a deep hardening steel will drawing the spine with the edge in water work or will it soften the edge even if in the water?

Thanks guys for all the help you've given me in the past and thanks ahead on this subject.

Jason Byers
 
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So if I got that right, I am to temper my blades at 350 for a total of six hours in the oven, pausing to cool them to room temp every two hours? Six hours seems like a long time. My last blades I put in for a total of 3 hrs with a (roughly) 20 min cool time in between the hours. Maybe I'll need to start tempering longer I guess.
 
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I see that he says to edge quench ONLY if you’re using it to be tested by an ABS type test. So is he saying not to edge quench for a knife that will never see chopping? What about drawing the spine and tang out a little more if you harden and temper the whole blade. I make quite a bit of hidden tang knives and feel safer to draw at least the area where the tang meets the guard. I am wondering if I can do this the same way I do 1080 by holding the edge and tip in water while taking a torch to the spine and tang. I don't want anyone to bad mouth me because of their misuse of a knife. Thanks for the quick answers.
 
An edge quenched blade will be more likely to pass the bend test as the spine is not hardened and should bend easily rather than breaking. For a chopper and one that may be used for batoning a hardened and tempered back spine would be better and less likely to deform from batoning, that and nobody should really be trying to bend your knives to 90 degrees. Those are my thoughts on the subject.
 
An edge quenched blade will be more likely to pass the bend test as the spine is not hardened and should bend easily rather than breaking. For a chopper and one that may be used for batoning a hardened and tempered back spine would be better and less likely to deform from batoning, that and nobody should really be trying to bend your knives to 90 degrees. Those are my thoughts on the subject.

Yep what he said! :thumbup: so just make those adjustments to fit your needs.

Jason
 
Ok guys thanks I'll just harden and temper the whole blade then draw the spine the same ias I draw my 1080 knives. Just wanted to make sure before I sold any 5160 knives. Merry Christmas!
 
Two tempers for two hours is the generally accepted practice except for very complex steels such as HSS that benefit from a 3rd temper.

A deep hardening steel can tolerate a slower quench from hardening temperatures and still fully harden. It will have no effect on the tendency of heat to reach the edge when drawing back the spine. For all practical purposes you can assume that any steel with the edge held in water and the spine heated with a torch is going to be okay. Heat actually does conduct more slowly in stainless and D2, but I doubt that will make much difference for what you're doing.
 
I did tons of testing on 5160 before my js test. The edge quench was the best because then spine never turned to martensite. I found drawing the spine with a torch tricky and had many failures. As far as the tempering temp start low like 275 and work your way up till you find what works on your equipment . I consulted several mastersmiths and all told me different temperatures. Test the blades on 2x4's till they don't chip or deform.
 
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