Please help with O1 heat treatment

[keltic230]

Hi all, first post. I'm getting into knife making, and for some reason, I can't get this right. I've also spent a ton of time reading to try to find where I could have gone wrong, but I can't find that either. I'm doing stock removal with O1

My process was this:

1) Stress relief: Heat to 1200 degrees F, then air cool. This is just for stress reduction

2) Hardening: Heat to 1450, hold for 20 min, quench in olive oil. Olive oil at 130 degrees.

This did not harden it. A file would not skate across it, and left gouges. So fuck, time to correct, then try again

1) Normalized 1600, cooled in air

2) Annealed at 1400, folded it up in high temp fiber insulation, and put a couple fire bricks over it. Left until cool

3) Hardening: Heat to 1200, let soak for 20 min, rise to 1475, hold for 20 min, quench in olive oil. Olive oil at 130 degrees.

I had better luck with the file, it skated across, but that may have been partly the oxidized coating.

4) Temper at 450 for 2 hours

I spent a couple hours cleaning up the knife, but I noticed a bang on the workbench left a scratch. I tried running a file across it, and of course it scratched.

What am I doing wrong? This is super annoying, and I didn't have any issue with my S30V heat treatment actually hardening it. I thought O1 was supposed to be easier.

Also, have I now screwed up this steel, or can I go through the normalize/annealing process again to reset it?\

Thanks for any help you can give

 

[Stacy E. Apelt - Bladesmith]

Well, there are several places that you can look at.
1) Since O-1 is a carbon steel, you will have a lot of decarb with those long soaks and multiple cycles. You may need to grind/sand it down a few thousandths to get to the hardened steel.
2) Are you positive it is O-1. Occasionally mistakes happen from suppliers, and mistakes happen more often in the shop when a piece of stainless is accidentally uses as a piece of carbon steel.
3) O-1 needs a soak, but 20 to 40 minutes in oven time excessive. 10 minutes is more than enough for any knife blade. A 1200F pre-heat is seen in the metallurgy books, but is mostly used on large and odd shaped parts in industry.
4) If you have a programmable oven, set the program something like this: Seg1 - ramp at 9999 to 1200F. ( place blade in at 1200°F), Hold for 3 minutes; Seg2 - ramp at 5000 to 1475-1495F, hold for 10 minutes. Remove blade and immediately quench in 120F oil. You should have hard steel.

 

[keltic230]

Thanks. I tried it again, following your suggestion, and still had issues with the file leaving marks. At the recommendation of a friend, I'm just going to finish the temper and clean it up to sharp. I'll see if it can hold an edge. One possibility is that I'm not getting full hardness (though I don't know why) and the file is simply harder than the hardened O1.

I got the steel from Jantz Supply, so I'm guessing it's correct. They seem pretty reputable but, as I say, I'm pretty new to the game.

Oh well, it's not like I'm making them for sale regardless haha all part of the learning process. Thanks again