Title:
PRODUCTION OF LOW YIELD RATIO HIGH TENSILE STRENGTH STEEL PLATE EXCELLENT IN UNIFORM ELONGATION
Document Type and Number:
Japanese Patent JP3229107
Kind Code:
B2
Abstract:
PURPOSE: To produce a building high tensile strength steel plate excellent in uniform elongation and low yield ratio without deteriorating its productivity by subjecting a steel having a specified compsn. to controlled rolling.
CONSTITUTION: This steel plate has a compsn. contg., by weight, 0.01 to O.20% C, 0.20 to 1.5% Si, 0.30 to 2.5% Mn, 0.005 to 0.10% Al and 0.001 to 0.01% N, in which the carbon equivalent Ceq. shown by the formula I is regulated to 0.30 to 0.60%, and the balance substantial Fe. Moreover, Cr, Ni, Mo or the like may be added thereto under certain conditions. The slab having the same compsn. is heated to ≤1150°C, is subjected to austenitic recrystallization region rolling and is successively subjected to unrecrystallization region rolling at ≥30% cumulative draft. After the rolling, it is subjected to primary forced cooling in the temp. range of 600 to 500°C at ≥5°C/S cooling rate, is subsequently cooled at a cooling rate of air cooling or below and is moreover subjected to secondary forced cooling from the temp. range of 450 to 400°C to ≤2O0°C at ≥5°C/S cooling rate.
Inventors:
Toshinaga Hasegawa
Shuichi Jinushi
Shuichi Jinushi
Application Number:
JP2445794A
Publication Date:
November 12, 2001
Filing Date:
February 22, 1994
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
C21D8/02; C22C38/00; C22C38/06; C22C38/54; C22C38/58; (IPC1-7): C21D8/02; C22C38/00; C22C38/06; C22C38/58
Attorney, Agent or Firm:
Tachio Chanogi (1 outside)