On Dec 31, 2:06*am, DD_BobK wrote:
On Dec 30, 3:41*pm, "Steve B" wrote:

http://en.wikipedia.org/wiki/Heat_treating

An interesting read regarding the topic being discussed. *And, it is very
applicable, because almost everyone has access to an oven, or a weed burner
that they could turn into a metal heater with just a few fire bricks. *A
very effective way of adding the properties you want to something you are
building, in this case, to keep the OP's firebox from warping.

And to the OP: *Keep in mind that in your final product, you will want a way
for the ash to fall away, so don't make the holes too small. *And that it
may take more than one to get to one that performs satisfactorily.

Steve

Great article on heat treating

but won't grate get hot enough during use to lose any heat treat
imparted?

Additionally, OP's expanded metal must be a heat treatable alloy in
order for the heat treatment to work.

My experience will cold worked steel products such as rolled, stamped
or expanded metals..... *they tend to be low carbon & thus on the
ragged edge of heat treatability . *

cheers
Bob

Yes, I have had my fireplace grate get hot enough to cause the iron to
melt and sag, so you would have to use a super-high metal to be strong
enough to not react with a long-burning fire.