casehardening

It is a merciless exposition of how iron and cinders impregnate the family life of a captain of industry, casehardening his heart, warping his honor, searing the joy of all who will not walk straight along the machine-made ways of the industry.

Machinery steel may be annealed in spent ground-bone that has been used in casehardening; but tool steel must never be annealed in this way, as it will be injured by the phosphorus contained in the bone.

How to Caseharden Large Pieces of Steel.—A box of cast or wrought iron should be provided large enough to hold one or two of the pieces, with sufficient room all around to pack well with the casehardening materials, which may be leather scrap, hoof shavings, or horn shavings, slightly burned and pulverized, which may be mixed with an equal quantity of pulverized charcoal.