It may be debarked, but any commercial heat-treating setup that's adequate
for A2 shouldn't produce a decarbed surface in the first place. They
probably heat it in a controlled atmosphere.
Carbon bearing steels that are hot worked tend to have the surface carbon
burned out, or the material is "decarbed". When you buy decarb free
material, you're buying material that has been further processed, usually
machined, to remove the zone that has lost its carbon content. Without
eliminating the surface material, it often won't heat treat properly because
of the lower carbon content.
If you do not have a controlled atmosphere furnace, there's almost no way
around using the stainless bag material if you intend for your parts to not
experience further decarburization, or scaling.
A thin layer of copper plate can be used, IIRC--apparently, this acts as a
barrier that the carbon wont readily pass through.
But I might be wrong on this one--Im recalling process control where a
certain amount was removed ( milled away ) on carbon steel alloy forgings to
remove hi carbon scale...
Then pretty sure that anything that went into the electric furnaces was
plated beforehand, where with gas furnaces, and IF the Co2 levels could be
controlled, then the plating wasnt needed......
I can't remember all the details anymore, but the copper plate did
definately play some role here.
This one answers it!
Thanks a lot ...
I have a home-made heat-treating oven (see my post on the subject if
interested) - it goes to about 2000F, is Omega-controlled and
to make, runs off 110V.
It doesn't have controlled atmosphere, so when heat-treating A-2
I do use SS bags/envelopes (McMaster is one source, MSC probably
it too). Sharp crease and a strip of brown bag paper put inside of the
envelope take care of not letting much of oxygen to get in contact
with the steel.
Harold and Susan Vordos wrote:
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