Deep hardening machinable aluminum killed high sulfur tool steel

Claim 1

A method of producing a low alloy, aluminum killed, water-quenched, resulfurized, martensitic deep hardening steel, highly machinable in the hardened condition comprising: a. providing an ingot of a composition consisting essentially of by weight: Carbon -- 0.33 to 0.42% Manganese -- 0.70 to 1.25% Phosphorus -- 0.025% maximum Sulfur -- 0.03 to 0.110% Silicon -- 0.15 to 0.45% Aluminum -- 0.019 to 0.077% Chromium -- 0.90 to 1.85% Molybdenum -- 0.10 to 0.50% boron and titanium in amounts to effect hardening of said steel, said boron and titanium being present in amounts of at least 0.0005 and 0.010 weight percent, respectively and the balance iron with residual impurities; b. hot working said ingot to form a hot worked product; c. water-quenching said hot worked product from an austenitizing temperature; and d. tempering said water-quenched hot worked product to a desired hardness.

Claim 2

A method of producing a low alloy, aluminum killed, water-quenched, resulfurized, martensitic deep hardening steel, highly machinable in the hardened condition comprising: a. providing an ingot of a composition consisting essentially of by weight: Carbon -- 0.33 to 0.42% Manganese -- 0.70 to 1.25% Phosphorus -- 0.025% maximum Sulfur -- 0.03 to 0.110% Silicon -- 0.15 to 0.45% Aluminum -- 0.019 to 0.077% Chromium -- 0.90 to 1.85% Molybdenum -- 0.10 to 0.50% boron and titanium in amounts to effect hardening of said steel, said boron and titanium being present in amounts of at least 0.0005 and 0.010 weight percent, respectively and the balance iron with residual impurities; b. hot working said ingot to form a hot worked product; c. water-quenching said hot worked product from an austenitizing temperature; and d. tempering said water-quenched hot worked product to a desired hardness.