发明名称 |
Hot-rolled steel sheet and cold-rolled steel sheet and manufacturing method thereof |
摘要 |
A steel sheet excellent in mechanical strength, workability and thermal stability and suited for use as a raw material in such fields of manufacturing automobiles, household electric appliances and machine structures and of constructing buildings, and a manufacturing method thereof are provided. The steel sheet is a hot-rolled steel sheet of carbon steel or low-alloy steel, the main phase of which is ferrite, and is characterized in that the average ferrite crystal grain diameter D (μm) at the depth of ¼ of the sheet thickness from the steel sheet surface satisfies the relations respectively defined by the formulas (1) and (2) given below and the increase rate X (μm/min) in average ferrite crystal grain diameter at 700° C. at the depth of ¼ of the sheet thickness from the steel sheet surface and said average crystal diameter D (μm) satisfy the relation defined by the formula (3) given below: 1.2≦̸D≦̸7  formula (1) D≦̸2.7+5000/(5+350·C+40·Mn)2  formula (2) D·X≦̸0.1  formula (3) wherein C and Mn represent the contents (in % by mass) of the respective elements in the steel.
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申请公布号 |
US7731808(B2) |
申请公布日期 |
2010.06.08 |
申请号 |
US20080068045 |
申请日期 |
2008.02.01 |
申请人 |
SUMITOMO METAL INDUSTRIES, LTD. |
发明人 |
TOMIDA TOSHIROU;IMAI NORIO;YOSHIDA MITSURU;KAWANO KAORI;WAKITA MASAYUKI;TOKI TAMOTSU;YASUYAMA MASANORI;NISHIBATA HITOMI |
分类号 |
C22C38/00;C21D8/02;C21D8/04 |
主分类号 |
C22C38/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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