Title:
COMPLEX METALLOGRAPHIC STRUCTURE TYPE HIGH TENSILE STRENGTH HOT-DIP GALVANIZED COLD ROLLED STEEL SHEET WITH EXCELLENT DEEP DRAWABILITY AND STRETCH-FLANGE FORMABILITY, AND MANUFACTURING METHOD
Document Type and Number:
Japanese Patent JP3912181
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a complex metallographic structure type high tensile strength hot-dip galvanized cold rolled steel sheet having excellent deep drawability and stretch-flange formability and to provide its manufacturing method.
SOLUTION: The complex metallographic structure type high tensile strength hot-dip galvanized cold rolled steel sheet has a composition which consists, by mass, of 0.01 to 0.05% C, 0.1 to 1.0% Si, 1.0 to 3.0% Mn, ≤0.10% P, ≤0.02% S, 0.005 to 0.1% Al, ≤0.02% N, 0.01 to 0.2% V, 0.001 to 0.2% Nb and the balance essentially Fe with inevitable impurities and in which the respective contents (mass%) of V, Nb and C satisfy a relation of 0.5×C/12≤(V/51+Nb/93)≤2×C/12. This steel sheet has a steel structure in which a primary phase is composed of a ferritic phase consisting of a polygonal ferrite phase and a bainitic ferrite phase and which has a secondary phase containing ≥1% by area ratio of a martensite phase. Further, this steel sheet has a hot-dip galvanized layer on the surface.
Inventors:
Yoshi Hiromi Ta
Saiji Matsuoka
Takashi Sakata
Saiji Matsuoka
Takashi Sakata
Application Number:
JP2002148855A
Publication Date:
May 09, 2007
Filing Date:
May 23, 2002
Export Citation:
Assignee:
jfe Steel Corporation
International Classes:
C22C38/00; C23C2/06; C21D9/46; C22C38/12; C22C38/14; C23C2/40; (IPC1-7): C22C38/00; C21D9/46; C22C38/12; C22C38/14; C23C2/06; C23C2/40
Domestic Patent References:
| JP5078779A | ||||
| JP2001303180A | ||||
| JP2000290730A | ||||
| JP2000109966A |
Attorney, Agent or Firm:
Kosaku Sugimura