Heat treat fail

I

IgorOs

Joined
Jan 2, 2020
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Hello everybody, begginer knifemaker here, after a long time of lurking on this forum, watching videos etc. I've decided to make my first knife.

I've managed to profile it and put on the bevels using only hand tools. After that I tried to heat treat it with a torch since it was the only thing I had. The HT attempt didn't work since i could not get the temp high enough and it left some kind of scale on the knife and the steel underneath is black. Anyone know what it is and can the blade still be salvaged?

The steel is 80crv2 and the plan was to do a simple HT, 3 normalization cycles, heat up a few shades over non-magnetic and quench in warm canola oil. I'm aware that 80crv2 requires a soak to get the best out of it but it was the only steel I had and don't have the equipment for soaking. Also sending out is not an option because no one near me provides that kind of service. I figured that even with a simple HT I should get a serviceable blade out of that steel.

Should I try to HT again (i will build a two brick forge, just waiting for the bricks) and if so do I need to remove the scale (if so how?) or do I just scrap the whole thing?
I've got the bug and will definitely keep at it even if I have to scrap this one :)
Pics of what I'm talking about below

https://imgur.com/a/o6T1ATL

Thanks
 
you should try it again.
unless you got the steel too hot, then you should be good to go! I wouldn't worry about the scale too much, just try it again.
 
Scale is normal after HT. It is also very hard. Soak the knife in sodium-bisulphate pickle (Ph down) overnight to loosen and dissolve it before you start sanding or grinding.

Re-do the HT as you described and it should come out OK.

Don't be fooled by testing the edge with a file after HT and it not skating. The blade will have a layer of soft decarb on it from the exposure to the flame and the oxygen in the air. After a few strokes the file will hit the hard stuff ans skate. In post-HT sanding and grinding, you will remove the decarb. Sand it all away before finishing the blade.
 
Thanks, that's great to hear, will remove the scale and re-do the heat treat as soon as i get my forge up and running
 
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