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 (mum) 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 (mum/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 grain diameter D (mum) satisfy the relation defined by the formula (3) given below: <?in-line-formulae description="In-line Formulae" end="lead"?>1.2<=D<=7 formula (1)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>D<=2.7+5000/(5+350.C+40.Mn)<SUP>2</SUP> formula (2)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>D.X<=0.1 formula (3)<?in-line-formulae description="In-line Formulae" end="tail"?> 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 |
US2008202639(A1) |
申请公布日期 |
2008.08.28 |
申请号 |
US20080068045 |
申请日期 |
2008.02.01 |
申请人 |
TOMIDA TOSHIROU;IMAI NORIO;YOSHIDA MITSURU;KAWANO KAORI;WAKITA MASAYUKI;TOKI TAMOTSU;YASUYAMA MASANORI;NISHIBATA HITOMI |
发明人 |
TOMIDA TOSHIROU;IMAI NORIO;YOSHIDA MITSURU;KAWANO KAORI;WAKITA MASAYUKI;TOKI TAMOTSU;YASUYAMA MASANORI;NISHIBATA HITOMI |
分类号 |
C21D8/04;C21D11/00;C22C38/04;C22C38/18 |
主分类号 |
C21D8/04 |
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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