Title:
【発明の名称】銅を含有した変態誘起塑性の加工容易な熱間圧延高張力鋼の製造方法
Document Type and Number:
Japanese Patent JPH11507103
Kind Code:
A
Abstract:
A method for producing a high strength hot-rolled steel sheet with good formability applicable to automobiles, industrial machines and the like is disclosed. The basic composition of TRIP steel is adjusted wherein Cu is added to improve the strength by precipitation hardening of a fine epsi-Cu. Other conditions are controlled to obtain a tensile strength of over 90 kg/mm2 with good formability. The steel is composed of 0.15-0.3% by weight of C, 1.5-2.5% by weight of Si, 0.6-1.8% by weight of Mn, 0.02-0.10% by weight of Al, 0.6-2.0% by weight of Cu, 0.6-2.0% by weight of Ni, the balance being Fe and inevitable impurities and has a microstructure of multi-phase structure consisting of ferrite, bainite, and retained austenite, or a granular structure (M-A constituents in bainitic ferrite matrix). The steel is finish rolled at a temperature of 750-880° C., water cooled from a water cooling initiation temperature of 680-740° C. to a water cooling termination temperature of 240x(% Mn+% Ni)-140 (° C.) to 540° C., and subsequently coiled at this temperature.
Inventors:
Kou Hyang Jin
Kimnak June
Park Sang Who
Kimnak June
Park Sang Who
Application Number:
JP52123998A
Publication Date:
June 22, 1999
Filing Date:
November 04, 1997
Export Citation:
Assignee:
Pohang Iron and Steel CEO., LDT.
International Classes:
C21D9/46; C21D8/02; C22C38/00; C22C38/02; C22C38/08; C22C38/16; (IPC1-7): C21D9/46
Attorney, Agent or Firm:
Takahashi Masahisa