Which foil for ss heat treat

[golfer1]

I will shortly be treating my first AEB-L and have read to use 321 or 309 foil. I'm thinking to use 309 but thought I would ask here and see what the pro's say.
Also read a little talcum powder in the packet will help reduce carb, what do you say about that.
Thanks for looking and best wishes.

 

[Geoff Flato]

I use 309 from trugrit, mainly because it was the cheapest I could find. It's a bit better than the 321 which most machine shop suppliers sell as well.
I usually put a couple squares of paper in the foil pack, and I've never had any decarb or scale formation. They come out nearly looking like they went in.
One thing to keep in mind with aeb-L is that it loves to warp. Plate quenching helps a fair bit (I use 1" aluminum) but even with that on long and thin blades (fillet knives, chefs knives) they still will warp on occasion. I've had them come out of the oven straight and warp in the liquid nitrogen as well. Generally on anything like that I'll heat treat essentially a drilled and profiled blank, and do all the grinding after HT. Keeping the belt wet with soluble oil coolant will help with heat buildup.
As for cryo it definitely seems to help, but I've tried aeb-L without it a few times, and it's still a pretty good blade.

 

[SBuzek]

I use 309 on every stainless

 

[golfer1]

Thanks much guys I will use 309.

 

[J. Hoffman]

I always used 309 for everything, but when I just reordered foil I got a roll of 321 also. The 321 should be good to 2000° so it should work in AEB-L. I'm also going to be using the 321 for normalizing and such. I've also never had the issue of AEB-L wanting to warp badly.