Heat Treat with SS Foil

B

B.V.

Joined
Dec 27, 2007
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How do you Heat Treat (lets say using O1 as an example) with the Stainless Steel Foil? Do you leave it in the foil during the quench or do you have to take it out somehow just prior? :confused:
 
I only heat treat stainless and air hardening steels with heat treat foil. Oil and water/brine hardening steels are more demanding because of time to quench, so you can't remove them from the foil before quenching. Quenching with the foil pack means that you're quenching an uneven surface and could possibly be trapping air in the pack. Even if a person worked out a sound method, the temperatures that carbon steels heat treat at don't produce enough decarb to make it worth the effort or expense in my opinion.
 
I agree, foil is only for "air quenching" steels.
Still I'm not happy with the decarb and scale if you just soak an unprotected blade. I solve the problem with Turco. Fair to middlin' protection and still just straight into the quench.

Rob!
 
I use foil for A2 but not O1. I am not sure anyone uses foil is a steel that is going to be quenched in liquid. I just heat, soak and then quench. Really not alot of decarb at 1500 F. From what I know, if you are quick you could use foil, you have less than 10 seconds to get it out of the foil and into the quench.
 
It's nearly impossible to remove the foil in time to beat the nose on most oil quenching steels. And as Patrick and Acrid pointed out, at temps around 1500, you wont have too much decarb unless you're waving the steel in the air or using a very oxidizing environment within a forge. Ovens are usually fine. With your stainless steels requiring temperatures in the 1900 to 2000F range and anywhere from 15 to 45 minute long soaks, you will burn up steel pretty fast.

Some tips on using foil. I've seen in a book somewhere that a maker recommended punching a small hole to prevent a vacuum or something like that. I don't do this. Almost every maker I know goes to extra lengths to AVOID ways for air to get in. If the blade is well wrapped, there won't be enough air to cause any trouble in the packet as long as you have it all sealed well. Crimp your 3 edges twice and flatten the crimps and you should be fine.

Also, when you fold over the foil, make sure the folded foil does not overlap the blade anywhere. I had a packet the other day that I folded not realizing the folded foil extended just past the tip. When I clamped the blade between the plates, the tip warped away from the foil. Not having had problems with warps in the past, I didn't see it until the blade was fully cooled and I had to heat to 1200 for a couple of hours, straighten it out, normalize it, and redo my HT. Now I cut open my packets after just a few seconds between the plates when the blade has stopped glowing (but somewhere above 400-500). That gives you a short window to fix any warps as the steel behaves almost like stiff rubber at this point before it begins to harden.

--nathan
 
But you can use foil with oil/water hardening steel for preliminary steps like spheroidal annealing. That seems to work and you end up with a blade that looks like it has been tempered all to hell as opposed to one with a layer of "grit" (thin decarb?) that must be ground or sanded off.
 
silver_pilate said:
Good tip, Joe. Hadn't thought about using foil for annealing.

--nathan
Click to expand...
No need to do it right out of the forge. The scale takes care of that. But if you are doing it after rough grinding right before quenching, then it helps a LOT!! Anti-scale compound is fine for a 10-20 minute soak before hardening, but it just doesn't do well at all when you are cooking that blade for 2 hours even if you are below critical.:D
 
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