and yet another...

rasret01

rasret01

Joined
Mar 31, 2009
Messages
153
Good morning all,

I am anticipating the delivery of my sugar creek kiln in a couple of days and I have a pretty basic question. Is it better to put the blade (O1) in the cold oven and bring it up to temp - manual controls - or should the blade go into the already hot oven.

Thanks for your insight.

Dick
 
I don't have my books here to give exact temps and times, but the normal procedure for steels like O-1 and any air quench steels it to place the cold blade in a per-heated 1200F oven. Allow to equalize ( come up to 1200F) ,and then ramp to austenitization temp. O-1 then needs a good 10-20 minute soak before quench.

Would there be any harm in placing most blades in a cold oven and heating it up with the oven....probably not. But, the more alloy ingredients in the steel, the more that can happen as the temperatures change.
 
my experience is that if the kiln has not reached equilibrium the infrared from the elements working to bring the thermal mass of the kiln up will drastically overheat the blade, especially if the kiln has exposed elements.. I bring the kiln up to austentizing temperatures and let it equilibrate for at least a half hour before I put the blade in. Before I did it that way I was having all sorts of problems. Leaving the blade in while the kiln comes up from dead cold also gives a lot of time for decarb and scale. YMMV

-Page
 
So should we not worry about the blade over-heating from radiant heat off the coils while ramping from the 1200 degree equalizing heat to our austenizing temp? It seems like this is the temp. range when scale/oxidation will make the blade most suceptible.
This is interesting stuff.
 
Not saying right or wrong, but what I've read on 01 is that it should be heated slowly, thoroughly heated at 1200° to 1250°, which means a soak, then ramped to 1475° to 1500°, and soaked again for 20 minutes, give, or take a little. As long as you have decarb protection, you can soak 01 in that temp range for hours with no internal changes in the steel, other than a good austenitization.
 
If you are going to do the ramp thing make sure to put some sort of shielding muffle between the elements and your blade. I may at some point do an experiment with an exposed blade with thermocouples on the surface to map out the radiant overheating effects

-Page
 
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