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TIL I was quenching in used oil way too hot for months

I kept getting weird micro cracks on my carbon steel blades after heat treat. Couldn't figure it out for like three months. Then I finally bought a cheap infrared thermometer from Harbor Freight for 30 bucks and checked my oil temp. Turns out I was quenching at like 180 degrees instead of the 120-130 range that works best for 1095 steel. The oil was way too thin and it was just shocking the metal too much. I had been heating the oil up on the side of the forge and just guessing when it was ready. Now I let it cool down to 125 before I dunk and my blades come out clean every time. Has anyone else been burned by guessing their quench oil temp instead of measuring it?

2 comments

2 Comments

angela_carter4d ago

Actually, 1095 usually needs a faster quench than that. Parks 50 or a thin oil at 120-130 is actually right on the money for it, not too hot. 180 would be too hot for most oils though, they get too thin and don't pull the heat out fast enough.

lucasking3d ago

Tbh the real wild card here is your steel's grain size before you even heat it. 1095 can be super picky if you didn't normalize it right, then even the perfect oil temp won't save you from a soft edge.