Does 1084 Air Harden?

O

oldwolf

Joined
Dec 29, 2002
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Forged out a little buffalo Skinner out of Aldo's 1084. Checked the hardness just for ducks and it's over 60 after grinding it to shape a little. Too late to temper it back or do I just reharden it and then temper? :confused:First time forging 1084.
 
You don't have to temper it back much. Give it another cycle at about 25 degrees higher than what you did the first time. You hardened it before you did any grinding? Sick, man...lol.
 
Time to learn something about heat treating !!! I would go 50-100 F above the first temper, 25 won't get you that much softer.....No 1084 does not air harden but normalizing [cooling in air from austenitizing temperature ] will get you 100 % pearlite which makes grinding a bit harder to do !!
 
It may have air hardened, stranger things have happened but I wouldn't have expected it, fine pearlite can be pretty hard, or you may just have a hard spot where you tested it. I would go through your normal thermal cycling procedure and actually harden it in a quench to be sure of the quality of the heat treat.
 
No,No,No I didn't heat treat it at all. It's just very hard after forging and cleaning it up with the grinder. I'll go a do a proper heat to critical and quench, so as Guy said I'll be sure of the heat treat. I'm no expert, but have heat treated my share of blades.
Thanks for the responses tho.
 
Some steel can work harden. And since hardening is a matter of cooling fast enough, theoritically a thin cross-section may be cooled fast enough to harden some. That I find unlikely. There may be a number of other possibilities.
Between forging and grinding, anneal (heat to critical then cool slowly, cooling can be slowed by putting the blade in dry ashes, dry sand, between layers of some insulating refractory or maybe sitting in the forge as it cools overnight).

ron
 
I tried the spherodizing anneal thingie at 1275 for the first time on a 1084 Aldo blade this past week. Didn't normalize it other than the rough normalize and trash can full of vermiculite anneal that I do when do when forging. The blade was a Moran ST24 style and I was worried about it warping in the quench because of the pronounced false edge, but it came out perfect. As for the anneal, no scale even without using anti scale!!! The blade came out covered in "soot" for lack of a better term, but no vislble decarb pits like you can get if you were to leave a blade in at critical for a long time and the anti scale flaked off.
 
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