Process for producing dual phase ferritic stainless steel strip
AssigneeAllegheny Ludlum Corporation
InventorsYeong-U Kim, Lewis L. Kish
Life of this patent
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Abstract
A method for producing a dual phase ferrite-martensite steel product from a cold rolled stainless steel. The method includes a step of rapidly heating the steel to annealing temperature in less than 30 seconds, followed by a step of cooling the heated steel at a cooling rate sufficient to transform austenite to martensite.
Claims11
A method for producing high tensile strength stainless steel sheet or strip consisting essentially of a dual phase of ferrite and martensite, the method comprising:
- rapidly annealing cold rolled stainless steel by heating said stainless steel to an annealing temperature in less than 30 seconds;
- and
- cooling the heated steel at a cooling rate sufficient to transform austenite to martensite.
A method for producing high tensile strength stainless steel sheet or strip consisting essentially of a dual phase of ferrite and martensite, the method comprising:
- rapidly annealing cold rolled stainless steel of the AISI 400 series by heating to an annealing temperature within the range of about 1900.degree. F. (1038.degree. C.) to about 2250.degree. F. (1232.degree. C.) at a heating rate of at least 200.degree. F. per second (111.degree. C. per second);
- and
- thereafter immediately cooling the heated steel from said annealing temperature in ambient air at a rate sufficient to transform austenite to martensite.
Dependencies are inferred from the claim text.