Preventing Decarbonization Of Tool Steel
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HARDENING CARBON STEEL FOR TOOLS
:
The Working Of Steel
It is especially important to prevent decarbonization in such tools
as taps and form cutters, which must keep their shape after hardening
and which cannot be ground away on the profile. For this reason
it is well to put taps, reamers and the like into pieces of pipe
in heating them. The pipe need be closed on one end only, as the
air will not circulate readily unless there is an opening at both
ends.
Even if used in connection with a blacksmith's forge the lead bath
has an advantage for heating tools of complicated shapes, since
it is easier to heat them uniformly and they are submerged and
away from the air. The lead must be stirred frequently or the heat
is not uniform in all parts of the lead bath. Covering the lead
with powdered charcoal will largely prevent oxidization and waste
of lead.
Such a bath is good for temperatures between 620 and 1,150 deg.F. At
higher temperatures there is much waste of lead.