Title:
PRODUCTION OF HIGH STRENGTH STEEL PLATE HAVING EXCELLENT LOW TEMPERATURE TOUGHNESS
Document Type and Number:
Japanese Patent JP3212438
Kind Code:
B2
Abstract:
PURPOSE: To produce a thick steel plate exceedingly excellent in TS, in rolling in the austenitic unrecrystallized region and the two phase region of austenite and ferrite, by controlling the rolling temp. by utilizing the draft per pass.
CONSTITUTION: At the time of subjecting a slab to hot rolling, the cumulative draft at ≥950°C is regulated to ≥30%, successively, rolling in which the cumulative draft at the Ar3 -20°C to the Ar3+180°C is regulated to ≥60% and, as for ≥60% of the total time of passes, the draft per pass is regulated to ≥15% is executed, and after that, air cooling or accelerated cooling is executed. In this way, intensive rolling is executed in the nallow temp. range in the vicinity of the Ar3, and the remarkable increase of the ferritic nuclear forming sites and the recovery and recrystallization of ferrite are enabled to refine the ferritic grains to a limit, by which excellent low temp. toughness and strength can be attained. As a result, the steel plate with ≥15mm plate thickness having exceedingly excellent low temp. toughness of ≥500MPa TS can be obtd.
Inventors:
Akihiko Kojima
Yoshio Terada
Hiroshi Tamehiro
Yoshio Terada
Hiroshi Tamehiro
Application Number:
JP3615194A
Publication Date:
September 25, 2001
Filing Date:
March 07, 1994
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
B21B3/00; B21B37/00; B21B37/76; C21D8/02; (IPC1-7): C21D8/02
Domestic Patent References:
| JP4202712A | ||||
| JP5271763A | ||||
| JP3223419A | ||||
| JP1136929A | ||||
| JP1312032A | ||||
| JP121016A | ||||
| JP59573A | ||||
| JP7242944A |
Attorney, Agent or Firm:
Tachio Chanogi (1 outside)