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US 3,973,950 AGranted
Low carbon calcium-sulfur containing free-cutting steel
AssigneeDaido Seiko Kabushiki Kaisha
InventorsTetsuro Itoh, Tetsuo Takahashi, Kiyoichi Yamano
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AssigneeDaido Seiko Kabushiki Kaisha
InventorsTetsuro Itoh, Tetsuo Takahashi, Kiyoichi Yamano
Estimating the term…
Low carbon calcium-sulfur containing free-cutting steel exhibiting improved machinability is disclosed. The said steel consists essentially of 0.03 to 0.10% carbon, up to 0.3% silicon, 0.8 to 1.5% manganese, 0.04 to 0.10% phosphorus, 0.20 to 0.45% sulfur, 0.0003 to 0.0050% calcium and the remainder being iron and inherent impurities such as copper, nickel, chromium and nitrogen; and is prepared by regulating the composition of the steel so that the value of theoretical Brinell hardness of the steel matrix, which is determined on the basis of the content of carbon, silicon, manganese, phosphorus, sulfur, copper, nickel, chromium and nitrogen in the steel, to a value between 110 and 130, and by forming and maintaining in the range of from 100 to 500 grams per steel-ton oxide inclusions of type JIS-A2 (ASTM-C) which soften or fuse at a temperature not higher than 1400.degree.C.
A low-carbon calcium-sulfur containing free-cutting steel, which consists essentially of 0.03 to 0.10% carbon, up to 0.3% silicon, 0.8 to 1.5% manganese, 0.04 to 0.10% phosphorus, 0.20 to 0.45% sulfur, and 0.0003 to 0.0050% calcium, 0 to 0.25% lead, 0 to 0.10% telurium, 0 to 0.15% bismuth, 0 to 0.2% tin, 0 to 0.2% zinc, 0 to 0.2% arsenic, 0 to 0.2% thallium, and the remainder being iron and impurities;
A low-carbon calcium-sulfur containing free-cutting steel, which consists essentially of 0.03 to 0.10% carbon, up to 0.3% silicon, 0.8 to 1.5% manganese, 0.04 to 0.10% phosphorus, 0.20 to 0.45% sulfur, 0.0003 to 0.0050% calcium, and the remainder being iron and impurities;
A low-carbon calcium-sulfur containing free-cutting steel, which consists essentially of 0.03 to 0.10% carbon, up to 0.3% silicon, 0.8 to 1.5% manganese, 0.04 to 0.10% phosphorus, 0.20 to 0.45% sulfur, 0.0003 to 0.0050% calcium and at least one of 0.05 to 0.25% lead, 0.02 to 0.10% telurium and 0.02 to 0.15% bismuth (total amount of Pb, Te and Bi being up to 0.25%), the remainder being iron and impurities;
A low-carbon calcium-sulfur containing free-cutting steel which consists essentially of 0.03 to 0.10 carbon, up to 0.3% silicon, 0.8 to 1.5% manganese, 0.04 to 0.10% phosphorus, 0.20 to 0.45% sulfur, 0.0003 to 0.0050% calcium, at least one of 0.05 to 0.2% tin, 0.05 to 0.2% zinc, 0.05 to 0.2% arsenic and 0.05 to 0.2% thallium (total amount of Sn, Z, As and Tl;
A low-carbon calcium-sulfur containing free-cutting steel which consists essentially of 0.03 to 0.10% carbon, up to 0.3% silicon, 0.8 to 1.5% manganese, 0.04 to 0.10% phosphorus, 0.20 to 0.45% sulfur, 0.0003 to 0.0050% calcium, and at least one of 0.05 to 0.25% lead, 0.02 to 0.10% telurium and 0.02 to 0.15% bismuth (total amount of Pb, Te and Bi:
Dependencies are inferred from the claim text.