Title:
HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2016/129213
Kind Code:
A1
Abstract:
Provided is a high-strength hot-dip galvanized steel sheet that has a component composition containing, by mass%, 0.07-0.25% C, 0.01-3.00% Si, 1.5-4.0% Mn, at most 0.100% P, at most 0.02% S, 0.01-1.50% Al, 0.001-0.008% N, 0.003-0.200% Ti, and 0.0003-0.0050% B, wherein Ti>4N is satisfied, and the remainder comprises Fe and unavoidable impurities. By area ratio in a cross section located 1/4 of the steel sheet in the thickness direction from the base-iron steel sheet surface, a ferrite phase is 70% or less (including 0%), a bainite phase is 20% or less (including 0%), a martensite phase is 25% or more, and a residual austenite phase is less than 3% (including 0%). The average crystal grain size of the martensite phase is 20 μm or less. The variation in the Vickers hardness of the martensite phase is 20 or less in terms of standard deviation. Also provided is a manufacturing method for the steel sheet.
Inventors:
HASEGAWA HIROSHI (JP)
FUNAKAWA YOSHIMASA (JP)
FUNAKAWA YOSHIMASA (JP)
Application Number:
PCT/JP2016/000303
Publication Date:
August 18, 2016
Filing Date:
January 21, 2016
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/14; C21D8/02; C21D9/46; C22C38/58; C23C2/02; C23C2/06; C23C2/28
Domestic Patent References:
| WO2011129452A1 | 2011-10-20 | |||
| WO2015162849A1 | 2015-10-29 |
Foreign References:
| JP2011153361A | 2011-08-11 | |||
| JP2011111670A | 2011-06-09 | |||
| JP2009209384A | 2009-09-17 | |||
| JP2010215958A | 2010-09-30 |
Other References:
See also references of EP 3257961A4
Attorney, Agent or Firm:
KUMASAKA, Akira et al. (JP)
Akira Kumasaka (JP)
Akira Kumasaka (JP)
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