Invention Grant
- Patent Title: Cold rolled steel sheet
- Patent Title (中): 冷轧钢板
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Application No.: US12919159Application Date: 2009-03-06
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Publication No.: US08343288B2Publication Date: 2013-01-01
- Inventor: Toshio Murakami , Akira Ibano
- Applicant: Toshio Murakami , Akira Ibano
- 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: JP2008-057319 20080307; JP2008-057320 20080307; JP2008-059854 20080310; JP2008-097411 20080403
- International Application: PCT/JP2009/054326 WO 20090306
- International Announcement: WO2009/110607 WO 20090911
- Main IPC: C22C38/44
- IPC: C22C38/44

Abstract:
Provided are the following cold-rolled steel sheets: 1) a cold-rolled steel sheet having higher stretch flangeability than conventional steels; 2) a cold-rolled steel sheet having a higher balance between elongation and stretch flangeability than conventional steels; and 3) a cold-rolled steel sheet heightened in all of yield stress, elongation, and stretch flangeability. The cold-rolled steel sheets are characterized by containing 0.03-0.30 mass % carbon, up to 3.0 mass % (including 0 mass %) silicon, 0.1-5.0 mass % manganese, up to 0.1 mass % phosphorus, less than 0.01 mass % sulfur, up to 0.01 mass % nitrogen, and 0.01-1.00 mass % aluminum and having a structure which comprises tempered martensite in an amount of 50% or more (including 100%) in terms of areal proportion and in which the remainder is ferrite. The steel sheets are further characterized in that at least one of the following structural factors has been regulated: the proportions of cementite particles and of the ferrite grains in the tempered martensite and the dislocation density in all structures.
Public/Granted literature
- US20110005643A1 COLD ROLLED STEEL SHEET Public/Granted day:2011-01-13
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