Heat treat discoloration

Chalet

Chalet

Joined
Aug 23, 2013
Messages
486
Hello! I’m new to this but have always enjoyed knives. Took a class a year and a half ago with a friend and then did some traveling and after a couple of cross country moves and job changes, finally have a house and a garage and subsequently the tools and a place to try this more. Just looking to make simple unique tools to use and give away.

I did do a search about this as well.

My question is that after heat treating knives they’ve been coming out of the oil with this discoloration. They’ve been singing a file and are noticeably harder than the raw steel when done side by side. Is this indicative of something I’m doing wrong, or of the metal not hardening? On a finished knife it was gone once sanded but wanted to see if it was something I should fix. It’s 80crv2 heated in a small Atlas and dipped into warm canola oil.

Thanks! I’ve been enjoying reading through here. There’s a lot of fun stuff to learn.

https://i.imgur.com/NitR73j.jpg
https://i.imgur.com/w3nXZYw.jpg
 
Is that right out of the quench with nothing done to them? That doesn’t look bad at all if so. My knives come out of the heat treat completely black.
 
That’s after tempering actually. But basically they didn’t look much different than that before tempering.
 
Ignore the colors on a blade both after the quench and after tempering. They are not really indicative of hardness or damage.

The "tempering colors charts" you find are for people who flame tempered tools like chisels and occasionally knife blades. This is a different process than an oven temper (which is a much better temper).
 
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Did I hear you right that your quenching these blades in oil while thy are still in the foil. Normally you do not foil wrap oil hardening blades. This way you get a nice fast even quench that’s not interrupted buy a foil envelope.
 
JTknives said:
Did I hear you right that your quenching these blades in oil while thy are still in the foil. Normally you do not foil wrap oil hardening blades. This way you get a nice fast even quench that’s not interrupted buy a foil envelope.
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I don’t see anywhere that he said he had the blades in foil.
 
Yeah, I think JT must have been reading a different thread. Regular quench and temper.
 
Yeah I didn’t use foil. Thanks everyone! I’ll give them that brass rod test today mentioned in another thread. I just wanted to see if the lighter colors towards the edge were indicative of softer metal.
 
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