Galvannealed steel sheet

US11035020B2 · US · B2

Patent metadata
FieldValue
Publication numberUS-11035020-B2
Application numberUS-201516067055-A
CountryUS
Kind codeB2
Filing dateDec 29, 2015
Priority dateDec 29, 2015
Publication dateJun 15, 2021
Grant dateJun 15, 2021

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  1. Title

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  2. Abstract

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  3. Assignees and inventors

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  4. Key dates

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  5. First independent claim

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  6. CPC / IPC classifications

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  7. Citations and related patents

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Abstract

Official abstract text for this publication.

A method for producing a coated steel sheet having a tensile strength of at least 1450 MPa and a total elongation of at least 17% is provided. The method includes providing a cold rolled steel sheet having a chemical composition in weight %: 0.34%≤C≤0.45%, 1.50%≤Mn≤2.30%, 1.50%≤Si≤2.40%, 0%<Cr≤0.7%, 0%≤Mo≤0.3%, 0.10%≤Al≤0.7%, optionally 0%≤Nb≤0.05%, and a remainder of Fe and unavoidable impurities. The sheet is annealed at an annealing temperature higher than the Ac3 transformation point of the steel, quenched to a quenching temperature lower than the Ms transformation point of the steel and between 150° C. and 250° C., reheated to a partitioning temperature between 350° C. and 450° C., maintained at the partitioning temperature for at least 80 s, then coated by galvannealing, with an alloying temperature between 470° C. and 520° C. A steel sheet is also provided.

First claim

Opening claim text (preview).

What is claimed is: 1. A galvannealed steel sheet made of a steel having a chemical composition including by weight: 0.34%≤C≤0.45%, 1.50%≤Mn≤2.30%, 1.50%≤Si≤2.40%, 0%<Cr≤0.7%, 0%≤Mo≤0.3%, 0.10%≤Al≤0.7%, optionally 0%≤Nb≤0.05%, and a remainder, the remainder including Fe and unavoidable impurities, a structure of the steel consisting of between 50% and 70% of martensite, retained austenite, and bainite. 2. The galvannealed steel sheet according to claim 1 , wherein the composition of the steel includes Al≤0.30%. 3. The galvannealed steel sheet according to claim 1 , wherein the composition of the steel includes 0.15%≤Al. 4. The galvannealed steel sheet according to claim 1 , wherein the composition of the steel includes 0.03%≤Nb≤0.05%. 5. The galvannealed steel sheet according to claim 1 , wherein the retained austenite has a C content between 0.9% and 1.2%. 6. The galvannealed steel sheet according to claim 1 , wherein the galvannealed steel sheet has a tensile strength TS of at least 1450 MPa and a total elongation TE of at least 17% as measured according to ISO standard ISO 6892-1, published in October 2009.

Assignees

Inventors

Classifications

  • during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

  • for remelting the coating · CPC title

  • Bainite · CPC title

  • containing Mn · CPC title

  • containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title

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What does patent US11035020B2 cover?
A method for producing a coated steel sheet having a tensile strength of at least 1450 MPa and a total elongation of at least 17% is provided. The method includes providing a cold rolled steel sheet having a chemical composition in weight %: 0.34%≤C≤0.45%, 1.50%≤Mn≤2.30%, 1.50%≤Si≤2.40%, 0%<Cr≤0.7%, 0%≤Mo≤0.3%, 0.10%≤Al≤0.7%, optionally 0%≤Nb≤0.05%, and a remainder of Fe and unavoidable impurit…
Who is the assignee on this patent?
Arcelormittal
What technology area does this patent fall under?
Primary CPC classification C21D8/0247. Mapped technology areas include Chemistry & Metallurgy.
When was this patent published?
Publication date Tue Jun 15 2021 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
What related patents are in patentsdb?
We list 7 related publications on this page (citations in our corpus or others sharing the same primary CPC).