Invention Grant
- Patent Title: High-strength cold-rolled steel sheet excellent in workability and method for manufacturing the same
- Patent Title (中): 加工性优异的高强度冷轧钢板及其制造方法
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Application No.: US12983482Application Date: 2011-01-03
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Publication No.: US08480819B2Publication Date: 2013-07-09
- Inventor: Yuichi Futamura
- Applicant: Yuichi Futamura
- Applicant Address: JP Kobe-shi
- Assignee: Kobe Steel, Ltd.
- Current Assignee: Kobe Steel, Ltd.
- Current Assignee Address: JP Kobe-shi
- Agency: Oblon, Spivak, McClelland, Maier & Neustadt, L.L.P.
- Priority: JP2010-019505 20100129
- Main IPC: C22C38/00
- IPC: C22C38/00

Abstract:
In a cold-rolled steel sheet in relation with the present invention, metallurgical structure of the steel sheet is made a mixture structure including bainite, residual austenite and tempered martensite, particularly, when the metallurgical structure is observed with a scanning electron microscope, bainite is constituted of composite structure of high temperature range forming bainite with 1 μm or above average distance between neighboring residual austenite and/or carbide and low temperature range forming bainite with below 1 μm average distance between neighboring residual austenite and/or carbide, and when the area ratio of the high temperature range forming bainite with respect to total metallurgical structure is made a and the total area ratio of the low temperature range forming bainite and the tempered martensite with respect to the total metallurgical structure is made b, a: 20-80%, b: 20-80%, and a+b: 70% or above are satisfied. The cold-rolled steel sheet in relation with the present invention is improved in all of the elongation (EL), stretch flange formability (A), and bending properties (R) with a good balance, is excellent in the overall workability, and has 980 MPa or above tensile strength.
Public/Granted literature
- US20110186189A1 HIGH-STRENGTH COLD-ROLLED STEEL SHEET EXCELLENT IN WORKABILITY AND METHOD FOR MANUFACTURING THE SAME Public/Granted day:2011-08-04
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