Inland Steel Company

Dennis T Quinto

Debanshu Bhattacharya

Michael O Holowaty

A steel billet is produced having free machining properties and substantially devoid of surface-cracking in the as-deformed condition and without surface conditioning. The steel contains bismuth and tellurium and may contain lead but in a smaller amount than is conventional in leaded, free machining steels. The billet was hot deformed at a temperature above about 920.degree. C. (1700.degree. F.) and below 1150.degree. C. (2100.degree. F.). The steel contains inclusions of MnTe and Bi.sub.2 Te.sub.3 as well as elemental Bi.

Semi-finished steel article

A free machining cast steel shape containing bismuth which functions as a liquid metal embrittler. The ability of the bismuth to function as a liquid metal embrittler is enhanced by restricting the total amount of ingredients which lower the wetting ability of the bismuth to less than the bismuth content and by controlling the amount of strengthening elements added to the steel.

Bismuth-containing steel

A free machining steel shape containing bismuth which functions as a liquid metal embrittler. The opportunity for bismuth to function as a liquid metal embrittler is increased by limiting the size of bismuth-containing inclusions to less than five microns.

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St. John, IN, United States of America

Dennis T Quinto