Title:
COLD ROLLED STEEL PLATE EXCELLENT IN WORKABILITY, HOT DIP PLATED STEEL PLATE AND THEIR PRODUCTION
Document Type and Number:
Japanese Patent JP3555483
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To impart excellent workability, chemical convertibility and hot dip plating suitability to high tensile strength steel.
SOLUTION: A slab having a compsn. contg., by mass, 0.0005 to 0.005% C, ≤2.0% Si, ≤3.0% Mn, ≤0.005% B, ≤0.1% Al, ≤0.15% P, ≤0.01% S and 0.005% N, furthermore contg. one or two kinds selected from 0.015 to 0.100% Ti and 0.001 to 0.015% Nb, and the balance Fe with inevitable impurities is subjected to hot rough rolling in such a manner that the rolling finishing temp. is controlled to the Ar3 transformation point to 950°C and is thereafter subjected to hot finish rolling by lubrication rolling of ≥80% draft in such a manner that the rolling finishing temp. is controlled to 500°C to the Ar3 transformation point. Next, with black film scale coated, it is subjected to heat treatment in the range of 650 to 950°C in an atmosphere in which reduction does not substantially occur to form an internal oxidizing layer on the surface layer part of matrix in the steel plate, the black film scale is removed by pickling, and cold rolling at 50 to 95% draft and recrystallization annealing at the recrystallization temp. to 950°C are executed.
Inventors:
Kyono Kazuaki
Shigeru Unno
Akio Toyoda
Shigeru Unno
Akio Toyoda
Application Number:
JP5505899A
Publication Date:
August 18, 2004
Filing Date:
March 03, 1999
Export Citation:
Assignee:
jfe Steel Corporation
International Classes:
C21D9/46; C22C38/00; C22C38/14; (IPC1-7): C22C38/00; C21D9/46; C22C38/14
Domestic Patent References:
| JP10204580A | ||||
| JP6179943A |
Attorney, Agent or Firm:
Kosaku Sugimura
Hiroshi Tokunaga
Kazuaki Takami
Umemoto Masao
Juno Aoki
Shiro Fujitani
Hiroshi Tokunaga
Kazuaki Takami
Umemoto Masao
Juno Aoki
Shiro Fujitani