Preventing Decarbonization Of Tool Steel

: 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


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.