Title:
HOT ROLLED STEEL SHEET AND COLD ROLLED STEEL SHEET HAVING EXCELLENT IMPACT RESISTANCE FOR AUTOMOBILES AND THEIR PRODUCTION
Document Type and Number:
Japanese Patent JP3039842
Kind Code:
B2
Abstract:
PURPOSE: To obtain a hot rolled steel sheet for automobiles which has excellent impact resistance and with which safety and weight reduction are attained by specifying the chemical compsn. of the steel sheet and specifying a static- dynamic ratio by adjusting the steel structure.
CONSTITUTION: The compsn. of the hot rolled steel sheet is composed, by weight%, of 0.010 to 0.10% C, ≤1.50% Si, 0.50 to 3.00% Mn, ≤0.010% S and 0.01 to 0.1% Al, one or two kinds selected from 0.05 to 0.15% P and 0.5 to 1.5% Cr and the balance Fe and inevitable impurities. In addition, the compsn. mainly composed of a martensite phase of 2 to 30% by volume ratio and a ferrite phase of ≤0.0010wt.% in solid soln. C quantity is used and its static- dynamic ratio is specified to ≥1.6. This hot rolled steel sheet is obtd. by hot rolling a steel slab at 850 to 780°C, starting cooling at a rate of ≥30°C/sec within 0.50sec to cool the steel sheet down to 750 to 650°C and stagnating the steel sheet for 4 to 60 seconds at 750 to 600°C, then cooling the steel sheet at a rate of ≤30°C/sec and coiling the steel sheet at 500 to 100°C.
Inventors:
Kazuya Miura
Shusaku Takagi
Nobutaka Kurosawa
Takaaki Hira
Toshiyuki Kato
Shusaku Takagi
Nobutaka Kurosawa
Takaaki Hira
Toshiyuki Kato
Application Number:
JP32273794A
Publication Date:
May 08, 2000
Filing Date:
December 26, 1994
Export Citation:
Assignee:
Kawasaki Steel Co., Ltd.
International Classes:
C21D8/02; C21D9/46; C22C38/00; C22C38/18; C21D1/19; (IPC1-7): C22C38/00; C21D8/02; C21D9/46; C22C38/18
Domestic Patent References:
| JP7188833A |
Attorney, Agent or Firm:
Junzo Ogawa (1 person outside)