PROCESS FOR PRODUCING HIGH TENSILE HOT-DIP ZINC-COATED STEEL SHEET OF EXCELLENT DUCTILITY AND ANTIFATIGUE PROPERTIES

Title:

PROCESS FOR PRODUCING HIGH TENSILE HOT-DIP ZINC-COATED STEEL SHEET OF EXCELLENT DUCTILITY AND ANTIFATIGUE PROPERTIES

Document Type and Number:

WIPO Patent Application WO/2003/078668

Kind Code:

A1

Abstract:

A hot rolled plate of a composition comprising 0.05 to 0.20 mass% of C, 0.3 to 1.8 mass% of Si, 1.0 to 3.0 mass% of Mn and the remainder consisting of Fe and inevitable impurities, having a composite texture consisting of ferrite main phase and second phase wherein the second phase comprises 80 vol.% or more of bainite and the remainder consisting of any one or two or more of martensite, retained austenite and pearlite and wherein the ratio of plate-thickness-direction average length to average length of the second phase is 0.7 or more, as a starting material, is subjected to cold rolling, given heat treatment, hot dip zinc coating and cooling operations. As a result, there can be obtained a high tensile hot-dip zinc-coated steel sheet exhibiting a ductility that is satisfactory for use as a material of automobile parts and also excellent antifatigue properties.

Inventors:

NAKAGAITO TATSUYA (JP)
SHIMIZU TETSUO (JP)
SAKATA KEI (JP)

Application Number:

PCT/JP2003/002190

Publication Date:

September 25, 2003

Filing Date:

February 27, 2003

Export Citation:

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Assignee:

KAWASAKI STEEL CO (JP)
NAKAGAITO TATSUYA (JP)
SHIMIZU TETSUO (JP)
SAKATA KEI (JP)

International Classes:

B32B15/01; C22C38/02; C22C38/04; C23C2/02; C23C2/26; C23C2/40; C21D8/02; (IPC1-7): C21D9/46; C22C38/04; C22C38/38; C23C2/40

Foreign References:

EP1096029A1	2001-05-02
JP2001192768A	2001-07-17
JP2001200338A	2001-07-24
JP2001207235A	2001-07-31
JPS6479322A	1989-03-24
JPS63105930A	1988-05-11
JP2001140022A	2001-05-22
JP2001064748A	2001-03-13
JPH05171344A	1993-07-09
JP2001207221A	2001-07-31

Other References: