MANUFACTURE OF TI ADDED HOT ROLLED HIGH TENSILE STEEL PLATE HAVING EXCELLENT FORMABILITY
Document Type and Number:
Japanese Patent JP3275783
PROBLEM TO BE SOLVED: To obtain the steel plate having excellent press workability and weldability by hot rolling the steel slab containing the specified quantity of Mn and Ti under the specified temperature condition and executing two-stage cooling controlling the cooling speed just after hot rolling.
SOLUTION: This steel slab is composed of, by wt., 0.13-0.20% C, ≤0.20% Si, 0.8-2.0% Mn, ≤0.025% P, ≤0.015% S, 0.005-0.15% sol Al, ≤0.004% N, 0.03-0.10% Ti and the balance Fe with inevitable impurities. The steel slab of this composition is hot rolled at the heating temperature of 1150-1300°C and the finish temperature of 800-930°C. The steel slab is cooled at the cooling speed of 10-22°C/sec up to ≤750°C and moreover the temperature in the range of ≥50°C higher than the cooling temperature just after rolling. Next, it is cooled at the cooling speed of 5-10°C/sec from that temperature and coiled at 600-700°C. Moreover, the hot rolling steel plate is the high strength steel plate having the tensile strength of ≥539 N/mm2.
February 08, 2002
June 25, 1997
SUMITOMO METAL IND LTD
C21D8/02; C21D9/46; C22C38/00; C22C38/14; C21D8/02; C21D9/46; C22C38/00; C22C38/14; (IPC1-7): C21D9/46; C21D8/02; C22C38/00; C22C38/14