Heat Treatment for Thin Blades

M

Mike Arsenault

Joined
Dec 23, 2006
Messages
84
Hello All,

So over the last 2 weeks I decided to take advantage of my colleges forging facilities to whip up a couple vegetable/light duty kitchen cleavers for my family as Christmas gifts. We had just finished a unit on forging and metallurgy and I figured "hey, if I can turn a piece of octagonal tool steel into a chisel, how hard could it be to turn an old bastard file into a couple of knives..." lol... yeah...

So here I am, 60 man-hours later, with one ALMOST straight 6 inch cleaver blade with a differential heat treatment, one collection of ultra hardened steel chips that took 30 hours to create, and a new obsession to boot.

I just could not for the life of me devise a way to keep that thin blade from warping when I quenched it, it seemed to be a chaotic stroke of luck that the one blade did as well as it did, as both were quenched and had to be re straightened several times. I even built a clamp from 2 pieces of 3/4 x4 inch bar, leaving only 1/8 of an inch of the edge exposed, but no use.

I pounded those files pretty thin ( probably no more than 50-70 thou by the time they were heat treated... is it even possible to quench at this thickness without totally warping? Or would one have to do the heat treatment with a thicker piece, then grind it down to size?

Thanks for any help, my apologies for anything that seems to have an obvious answer, the learning curve is steep with this hobby! Lol, though I'm doing my best to read the @#$*&*# manual.

cheers
 
Gabe Newell said:
Wouldn't using quench plates help with this?
Click to expand...

I believe quench plates are only used on air hardening steels. If he's hammering out files, he's supposed to be quenching in some kind of fast oil.

Myself, I would heat treat these thin blades before grinding them. Might use a few more belts, but would cut down on the warping.
 
Yeah, they're pretty thin (0.050") . Quench plates? , like slapping two pieces of metal around it? Tried that ( bolted 'em between 2 peices of 3/4 x 4" bar stock), but maybe they weren't constructed well enough... I tried both water and oil as a quench ( quenching oil but unsure of type). Both queches warped, though the oil not quite so badly. I tried water more, as I was still able to file the edge slightly after an oil quench, whereas the water made it hard as hell.
 
Plate quenching can only be used on high hardenability steels -the air hardening types. ..What did you do before the quench ? Normalize 1 to 3 times ?
 
Hehe... hell no mete... I came here (or somewhere) and read about the pre-quench normalizing AFTER I messed it all up. I would just quench, then take the warped piece of junk into the forge to straighten it out, then fire it back into the oven till it was 1450, then quench again. I annealed the files before I hammered'em out, but thats it. I suppose all the stress left over from my hammering didn't help matters any...
 
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