1080/1084 temper

Z

ZeroOne

Joined
Apr 21, 2013
Messages
3
Hi,
I have been reading these forums for a while and have to thank all of you folks out there for you wealth of knowledge and passion for bladesmithing. I am beginning my knife making using 1084. After reading how to heat treat it I am confused about how soon after harding should the knife be placed in the oven? Should it be allowed to cool to room temperature or right away?
This is from: http://www.knivesby.com/knifemaking-Kevin-Cashen-treating-1084.html

"The sooner you can get to the temper after the blade has reached Mf (THIS IS ROOM TEMP AT LEAST) the better off you will be. Not letting the blade completely cool to Mf will result in many problems, not the least of which would be the previously mentioned retained austenite."

Thanks.
 
The martensitic conversion from austenite does not stop until below 200°F, and is considered finished at room temperature. You then have brittle martensite that needs immediate tempering.
 
Long enough to scrub them with a little dish detergent and wash the quench oil off before you put them in the oven. Ask me how I know :)

Seriously though, 1084's not likely to explode on you. Don't dawdle, but it's not like you have to have them in the tempering oven 37 seconds after the quench.
 
ESPECIALLY if you have to wait for your oven to cool down after hardening. ;)
Jason Fry said:
Long enough to scrub them with a little dish detergent and wash the quench oil off before you put them in the oven. Ask me how I know :)

Seriously though, 1084's not likely to explode on you. Don't dawdle, but it's not like you have to have them in the tempering oven 37 seconds after the quench.
Click to expand...
 
The word "immediate" is use in tempering instructions more to avoid the stabilization of austenite than to prevent cracking. Retained austenite will become stabilized with time...the less time the less worry. As far as cracking/breaking the blade, unless you subject it to some force or stress.....like going to the grinder to "clean it up a bit"....there is little worry about it spontaneously cracking. Drop it on the cement floor, and it may well break. The best procedure is to plan the temper ahead. Turn on the kitchen oven and get it at 400F when you start the HT. If you use the HT oven for tempering, just let it cool off. A few hours is no problem. Overnight isn't really a problem either. I wouldn't suggest waiting more than that, though.
 
Agree with Stacy. The scrub the oil tip is for the kitchen oven. I usually do my first cycle in the kitchen oven, then my second cycle 25 degrees higher back in the kiln. First cycle is quick after, second cycle is usually the next day.
 
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