Inland Steel Company

Debanshu Bhattacharya

Michael O Holowaty

Dennis T Quinto

Howard M Pielet

John R Knoepke

Daniel Rellis, Jr

Purnendu K Dasgupta

Larry A Frank

Charles R Jackson

Molten steel containing an undissolved alloying ingredient denser than molten steel (e.g. Pb and/or Bi) flows from a tundish to a continuous casting mold. Various expedients are employed to prevent large globules of undissolved alloying ingredient from flowing out of the tundish into the mold. Another expedient prevents large quantities of undissolved alloying ingredient from accumulating on the bottom of the tundish.

Apparatus for preventing undissolved alloying ingredient from entering

Preventing undissolved alloying ingredient from entering continuous

Molten steel containing lead and/or bismuth is continuously cast without explosions in the casting mold. The mold has sidewalls whose interior surface is coated with a non-organic lubricant which is not violently reactive thermally or chemically, under the conditions of continuous casting existing within the mold, to produce explosions, and does not breakdown under those conditions to produce a compound which is explosive under those conditions. Conventional petroleum-base lubricants for the continuous casting of molten steel are excluded.

Method for preventing mold explosions during continuous casting of free

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.

Free machining steel with bismuth

Lead, bismuth and tellurium and/or sulfur are added to steel, to increase the machinability of the steel, in an addition alloy consisting essentially of 5-40 parts lead, 5-40 parts bismuth, up to 6 parts tellurium and up to 25 parts sulfur. The alloy contains at least one of the group tellurium and sulfur, and the alloy has a melting point of at least about 400.degree. C. (752.degree. F.).

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Matteson, IL, United States of America

Debanshu Bhattacharya