Heat treating/tempering O1 steel?

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brano880

Joined
Jun 18, 2016
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It s my first time making a knife and I heat treated it with a MAP torch in a makeshift forge. It was a dull red inside so I thought it was a good temperature to quench. Once I took off the lid, it began to cool off really quickly and within 10-15 secs before I quenched it wasn t glowing at all. Once it reached about 125 F, I stuck it in to temper at 400F for 2 hours. I feel like I might not have gotten it hot enough. Would it be safe to re-heat treat it? Would it be worth the work in the end?
Any info is helpful, thanks
 
It's safe to re-heat treat it. It probably didn't harden, as you lost too much heat. Get a telescoping magnet, heat until it becomes non magnetic, go two shades brighter, and quench. It's not ideal, but the minimum you can do. Simpler steel like 1084, 1080, 1075 will be much more forgiving of simple heat treatments.
 
The transfer from forge to the quench tank should be smooth and immediate. A few seconds at most.

If you have some sort of forge that has to be taken apart to get the blade out, that is the biggest problem. You should be able to grab the blade by the tang with a pair of long needle nose pliers or a set of tongs and pull it right out and stick it immediately in the oil..
 
Willie71 said:
It's safe to re-heat treat it. It probably didn't harden, as you lost too much heat. Get a telescoping magnet, heat until it becomes non magnetic, go two shades brighter, and quench. It's not ideal, but the minimum you can do. Simpler steel like 1084, 1080, 1075 will be much more forgiving of simple heat treatments.
Click to expand...

Good to know, thanks.

Stacy E. Apelt - Bladesmith said:
The transfer from forge to the quench tank should be smooth and immediate. A few seconds at most.

If you have some sort of forge that has to be taken apart to get the blade out, that is the biggest problem. You should be able to grab the blade by the tang with a pair of long needle nose pliers or a set of tongs and pull it right out and stick it immediately in the oil..
Click to expand...

I think I'm going to make a small forge- something that would make the knife easier to access. It was recommended that since it was my first time I should make something like a tin can forge which would give me the ability to quench it right away. Would you recommend anything else/different?
 
Have you checked out Atlas Forge? He's a member here and the forges are very reasonably priced. One day in the not too distant future the urge to forge some damascus is going to overwhelm me and I'm going to pick one up...in BLACK! :D
 
A coffee can forge or other tiny forge isn't very good for HT. You want a forge with better chamber size and a real burner. You can build a small 12" long forge for less than $100 easily. Atlas sells very nice small and medium size forges that are virtually plug-and-play. They are good units and affordably priced.

Filling out your profile would tell us something about you ( age, location, hobbies, occupation, etc.) as well as allow someone near you to offer you a shop visit and do the HT for you.
 
I'm quite sure it hardened to some extent. I'm working with O1 and once I get it hot (glowing), it basically hardens enough to make filing extremely difficult.

Also, if you approximate your blade to be the shape of a flat bar (not paper thin), then it should lose around 50°C in the first 10 - 15 seconds. After around 300 seconds, it would begin hardening.
 
O1 will air harden to a certain extent. Not enough for knife use, but it will harden. If you got it above critical, it will form pearlite which is much harder on tooling than a spheroidized state.
 
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