Oil Quenching Stainless?

L6steel

L6steel

Joined
Sep 23, 1999
Messages
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When you oil quench ats-34 or 440c, can you leave the blades in the foil wrap and dunk it or do they need to be removed? Also, what kind of oil is best? Thanks!
 
when i did heat treat 440c i use napp gas torch took it up to cherry/orange the dipped it blade down in a painter roll tray so it whent about 3/4 of the way deep in ATF fluid. then cleaned off the scale off. i then heated the spine to blue to temper. don't know a exact hardness but i worked i did my first few knives that way until i started sending them out.
 
stainless is an animal all unto itself. It takes a lot longer for carbon to go into solution with stainless, 440c needs to be soaked 30 min at 1850 so the torch method is not really recomended. I heat treat stainless in foil and leave it in the foil to quench. Motor oil will work but can cause some problems as it can cavitate because of its lower flash point than actual quenching oil. ATF tranny fluid is better than motor oil and mineral oil is the best. Olive oil also works well. Cheveron and the other oil companies sell oils that are actually made for quenching steels.
 
About 18 years ago I tried a multiple quench with 440c forged from a ball bearing or gate check from an oil pump. It was a ball about 2 inches in diameter. I quenched test blades from once to 10 times. I found no significant difference from three quenches to 10. A significant difference from once to three. The multiple quench took the place of 30 minute soak times. The blades were only submerged 1/2 way down in the oil.. I used Brownells quick quench. A slower oil like Texaco type might work better.

I got up to 18 cuts on test rope and the blade flexed to 90 degrees without any damage.

This is the best performance I have seen with 440c.
 
Mr. Fowler,
Thanks for the 440C quench instructions, as I had been wondering about this too. What temperature did you use to draw the blade back?
 
I tried to find my old experimental notes, they are hiding! I beleive that I used a 350 f draw, two hour soak, allowing it to cool to room temp in my Paragon. Then a repeat for three total. I would suggest that if you try the multiple quench, also determine the appropriate temper via the edge flex. Undoubtably your steel will vary from the stuff I used. I now use increments of 10 degrees when seeking the optimum tempering temperature. Good Luck and Take Care
 
This is really interesting. I was under the impression that 440C was an air hardening steel so this oil quenching is somewhat of a shock to me.

Ed, did you use foil to protect the blade?
 
many stainless steels are air hardening but that does not preclude them from being quenched in oil or water.
 
I did not use foil, I heated the blades with a 000 Victor tip, 3x flame on my oxy-acet rig, brought the lower half of the blades up to critical and quenched as soon at they reached critical. There was some scale, but not much.
 
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