O1 heat treating question

smitty0331

smitty0331

Joined
Dec 5, 2006
Messages
892
I've been using O1 for about 2 yrs now, for stock removal knives, and I can't seem to beat the large amount of scale i always get when tempering. My forge is propane, with a thermocouple, and I heat up to about 1475f then add a little charcoal and stick my blade in and hold for 10 min. then quench. What am I doing wrong? Can I use s.s. foil with an oil hardening steel?
 
Hi Smitty,
I really like this stuff. It takes a try or two to get it down right.
I will buy more when I run out.
 
Last edited:
ATP anti-scale. Brownell's and a few others sell it. You just paint it on, let dry, then do your HT. I have had very good results with it. If possible, increase your soak time a bit more. Straight in cold, the blade will take a few minutes to come up to full heat. I would suggest doubling your soak time.
 
i use a kiln and soak for 15-20 min but dont think that decarb is too bad but then again i dont take my blades to 80% finished before HT
I perfer to HT thick and grind the last 40% after hard
 
smitty0331 said:
I've been using O1 for about 2 yrs now, for stock removal knives, and I can't seem to beat the large amount of scale i always get when tempering. My forge is propane, with a thermocouple, and I heat up to about 1475f then add a little charcoal and stick my blade in and hold for 10 min. then quench. What am I doing wrong? Can I use s.s. foil with an oil hardening steel?
Click to expand...

In the first sentence I thought "wow, you really are encountering some strange issues", then I realized you were heating the steel for hardening. An often confused terminology is "tempering" and "hardening", your problem operation is hardening, the tempering process comes after that at around 400F to relive some stress and toughen the blade.

It does sound like an inordinate amount of scale, I would first double check the accuracy of the thermocouple because it sounds like it could be a combination of overheating and atmosphere adjustment.

You actually have two separate problems to deal with, decarburization and scaling, adjusting the atmosphere too lean will get you more scaling while adjusting it too rich could get you decarb. I would go for a neutral flame that leans slightly toward the rich side. Adjust your forge until the flame stops just at the door opening and then give it enough gas to get the flame to creep out an inch or two.

Foil would be a pain for most oil hardening steels, but I and many others have worked with the anti-scale compounds with quite a bit of success.
 
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