Title:
高強度合金化溶融亜鉛めっき鋼板およびその製造方法
Document Type and Number:
Japanese Patent JP5867436
Kind Code:
B2
Abstract:
Provided is a high-strength galvannealed steel sheet having a chemical composition to which expensive alloy elements are not actively added, excellent formability including elongation, bendability, and stretch flange formability, and a tensile strength of 900 MPa or more. A high-strength galvannealed steel sheet has a chemical composition containing, by mass%, C: 0.14% or more and 0.24% or less, Si: 0.8% or more and 1.8% or less, Mn: 1.0% or more and 3.0% or less, P: 0.020% or less, S: 0.0040% or less, Al: 0.01% or more and 0.1% or less, N: 0.01% or less, Ca: 0.0001% or more and 0.0020% or less, and the balance comprising Fe and incidental impurities, and a microstructure, in which the total area ratio of a ferrite phase and a bainite phase with respect to the whole microstructure is 30% or more and 70% or less, in which the area ratio of a tempered martensite phase with respect to the whole microstructure is 20% or more and 40% or less, in which the area ratio of a retained austenite phase with respect to the whole microstructure is 1% or more and 5% or less, in which the area ratio of a martensite phase with respect to the whole microstructure is 2% or more and 20% or less, and in which the total area ratio of cementite and a pearlite phase with respect to the whole microstructure is 10% or less.
Inventors:
Hidenao Kawabe
Takeshi Yokota
Takeshi Yokota
Application Number:
JP2013068297A
Publication Date:
February 24, 2016
Filing Date:
March 28, 2013
Export Citation:
Assignee:
jfe Steel Corporation
International Classes:
C22C38/00; C21D9/46; C22C38/06; C23C2/02; C23C2/06; C23C2/28; C23C2/40
Domestic Patent References:
| JP2012214868A | ||||
| JP2003171735A | ||||
| JP2011157583A | ||||
| JP2009203548A |
Foreign References:
| WO2012036269A1 | ||||
| WO2011065591A1 |
Attorney, Agent or Firm:
Shigeru Inoue
Kazuhiro Mori
Kazuhiro Mori