Title:
EFFECTIVE PRODUCTION OF COLD ROLLED STEEL SHEET EXTREMELY EXCELLENT IN DEEP DRAWABILITY
Document Type and Number:
Japanese Patent JP3137754
Kind Code:
B2
Abstract:
PURPOSE: To effectively produce a cold rolled steel sheet extremely excellent in deep drawability by subjecting steel contg. specified amounts of C, Si, Mn, P, S, Al, N, B, Ti and Nb to specified hot rolling, cooling and annealing and thereafter executing specified cooling and annealing.
CONSTITUTION: Steel contg., by weight, ≤0.003% C, ≤0.1% Si, 0.05 to 0.4% Mn, ≤0.05% P, ≤0.05% S, ≤0.06% Al, ≤0.004% N and 0.0001 to 0.001% B as well as 0.02 to 0.1% Ti and/or 0.002 to 0.04% Nb, and the balance Fe with inevitable impurities is heated to ≤1200°C and is thereafter subjected to hot rolling. At this time, the coarse finish thickness is regulated to ≥50mm and the effective strain εeff shown by the formula is regulated to ≥50%. Cooling is started within 1S after the completion of the finish rolling at 880 to 950°C, and it is cooled to ≤830°C at ≥20°C/S and is coiled at 680 to 800°C. This hot rolled steel strip is subjected to cold rolling at 70 to 85% draft and continuous annealing at 840 to 900°C and is moreover subjected to cold rolling at ≥50% draft and ≥85% total draft and continuous annealing at 840 to 900°C.
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Inventors:
Hirohide Asano
Nobuhiko Matsutsu
Jun Itami
Nobuhiko Matsutsu
Jun Itami
Application Number:
JP22138192A
Publication Date:
February 26, 2001
Filing Date:
August 20, 1992
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
C21D8/04; C21D9/48; C22C38/00; C22C38/28; C22C38/14; (IPC1-7): C21D9/48; C21D8/04
Domestic Patent References:
| JP3170618A | ||||
| JP452229A | ||||
| JP397813A |
Attorney, Agent or Firm:
Yu Shiina (1 person outside)