Post fab treating

A guy in another newsgroup wants to make a small box for a pellet stove, and so far, we've decided that if he can find a small piece of cnc punched plate, that would be the way to go. I suggested post fab heat treatment.

Now, the question.

After you heat it up in an oven, say 500+ for an hour or so, do you let it cool slowly, or dump it into oil?

What result do each of those actions do?

What he wants is to keep this little box from deforming, even with the small fire of a pellet stove, and I've had questions about larger applications, and want to understand more about this.

Good answers or good links appreciated

Steve

Reply to
Steve B
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It ALL depends on what kind of material the punched plate is made from. If it is mild steel, A36 for instance, it won't harden up or anneal anyway, let alone at that low temp of "500+". Thickness will matter a lot in this application. If the plate gets hot enough to glow when in operation, it will oxide rapidly and, pretty soon, there won't be any material left. We used to make maple syrup in a home made evaporator fueled by wood. I made the grate bars out of 5/8" diameter rebar. The bars didn't even last one season. They just got smaller and smaller, day by day. Sagging is also a problem.

Cast iron works much better, as long as you NEVER allow ashes to build up high enough to touch the grate from below.

Depending on the size of the device, if you can find a cast iron sewer floor drain with appropriate sized holes or slots, that should work well.

Pete Stanaitis

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Reply to
Pete S

Steel won't work very well for this application. It will quickly deform.

as mentioned cast iron is the ideal. pretty hard for the home shop type to do.

Stainless steel, #304, in a suitable thickness will work and can be welded into the correct shape. You should know this material is a stone bitch to saw or drill. It work hardens and dulls your tools.

Karl

Reply to
Karl Townsend

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