Title:
HIGH STRENGTH HOT ROLLED STEEL SHEET EXCELLENT IN WORKABILITY AND ITS PRODUCTION
Document Type and Number:
Japanese Patent JP3536412
Kind Code:
B2
Abstract:
PURPOSE: To produce a high strength hot rolled steel sheet excellent in workability such as stretch-flanging properties by specifying the compsn. constituted of C, Si, Mn, Nb, Al, S, N and Fe and forming its metallic structure into the one essentially consisting of ferrite.
CONSTITUTION: This high strength hot rolled steel sheet is the one having a compsn. contg., by weight, 0.010 to 0.020% C, 0.5 to 2.0% Si, 0.45 to 3.2% Mn, 0.07 to 0.30% Nb, 0.01 to 0.05% Al, ≤0.005% S and ≤0.005% N in the ranges satisfying Mn/Si=0.9 to 1.6 and Nb/8(C+12N/14)=0.8 to 1.5, moreover contg., at need, ≤0.15% Ti, and the balance Fe with inevitable impurities, having a metallic structure of ≥95% ferrite volume ratio and having excellent stretch- flanging properties. This steel sheet is produced in such a manner that the steel stock having the same compsn. is heated to a temp. T satisfying the inequalities I or II, e.g. to 1000 to 1300°C, rolling is finished at the Ar3 point to the Ar3 point + 100°C, within two seconds from the same, cooling is started, and it is cooled to 800 to 650°C at 10 to 50°C/sec and is coiled at 500 to 650°C.
Inventors:
Kurosawa, Nobutaka
Miura, Kazuya
Kato, Toshiyuki
Miura, Kazuya
Kato, Toshiyuki
Application Number:
JP7300495A
Publication Date:
June 07, 2004
Filing Date:
March 30, 1995
Export Citation:
Assignee:
KAWASAKI STEEL CORP
International Classes:
C21D8/02; C21D9/46; C22C38/00; C22C38/12; C22C38/14; (IPC1-7): C22C38/00; C21D8/02; C21D9/46; C22C38/12; C22C38/14
Attorney, Agent or Firm:
杉村 興作 （外４名）
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