So I have been working on my very first knife, made from a O1 steel, for a while now. Today I attempted to heat treat, but I think I made a mistake. Any advice would be greatly appreciated. I began by using a torch to harden the blade. It definitely changed colors, but it never got red hot. So I made a really hot bonfire and put in the embers for a while and it still didn't really get red hot..but I wasn't sure. I quenched it and tempered it for 2 hrs at 475F. Now I am unsure if I did this right..I have already spent a lot of time on this knife. What would be the best way to proceed? Can I reharden it? Again, any advice would be great, thanks!
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A question about heat treating
- Thread starter Adam25
- Start date
It needs to be the right shade of red (temp) for the right amount of time (steel fact sheet, consult it) and embers alone aren't hot enough. You need some more heat. Google up brake drum forge. In a pinch, but not very controlled or repeatable you could try to bury the blade in the coals and run a hair dryer blowing into the coals to get them really, really hot. I've never tried it, just a random idea.
You can anneal and reharden it since it was buried in the coals it should be fine for another go.
You can also make a new one and send it off for heat treat. They will do it for a fair, relatively low price and it will be perfect. Just don't sharpen it all the way before heat treat.
After heat treating, but before tempering, you can test with a file. If it skates over the knife metal without leaving marks you have hardened the metal.
Now, of course you might have only hardened the top layer, for instance with torches. this can happen. This is kind of like case hardening. Problem is, it isn't very deep. Final shaping and sharpening might reveal soft metal.
Ask a mod to move this over to the right section, more knowledgable people than me will chime in quickly. Also read the threads there, you aren't the first to have this problem. Good luck and have fun!
And pics. We need pics!
You can anneal and reharden it since it was buried in the coals it should be fine for another go.
You can also make a new one and send it off for heat treat. They will do it for a fair, relatively low price and it will be perfect. Just don't sharpen it all the way before heat treat.
After heat treating, but before tempering, you can test with a file. If it skates over the knife metal without leaving marks you have hardened the metal.
Now, of course you might have only hardened the top layer, for instance with torches. this can happen. This is kind of like case hardening. Problem is, it isn't very deep. Final shaping and sharpening might reveal soft metal.
Ask a mod to move this over to the right section, more knowledgable people than me will chime in quickly. Also read the threads there, you aren't the first to have this problem. Good luck and have fun!
And pics. We need pics!
Last edited:
- Joined
- Nov 29, 2012
- Messages
- 232
Hi Adam, Welcome aboard.
The critical temp for O1 is right around 1500 degrees (bright orange).... If it didn't change colors much you didn't get anywhere near austentizing (hardening) heat.
Cheapest simplest way to get these temps in your back yard is to use charcoal (not briquettes). anykind of trench you can blow air through/across will do... get them going and put some kind of fan on them... when they are bright orange bury the blade in until it is BRIGHT orange through, it is very possible to overheat the blade so once it is bright orange, but before it goes yellow, quench in oil (about any kind will do, some guys use old motor oil). Then temper...
hope that helps,
Good luck.
The critical temp for O1 is right around 1500 degrees (bright orange).... If it didn't change colors much you didn't get anywhere near austentizing (hardening) heat.
Cheapest simplest way to get these temps in your back yard is to use charcoal (not briquettes). anykind of trench you can blow air through/across will do... get them going and put some kind of fan on them... when they are bright orange bury the blade in until it is BRIGHT orange through, it is very possible to overheat the blade so once it is bright orange, but before it goes yellow, quench in oil (about any kind will do, some guys use old motor oil). Then temper...
hope that helps,
Good luck.
