Title:
METHOD FOR MANUFACTURING HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET, METHOD FOR MANUFACTURING HOT-ROLLED STEEL PLATE FOR HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET, METHOD FOR MANUFACTURING COLD-ROLLED STEEL PLATE FOR HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET, AND HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET
Document Type and Number:
WIPO Patent Application WO/2017/090236
Kind Code:
A1
Abstract:
Provided is a method for manufacturing a high-strength hot-dip galvanized steel sheet, a method for manufacturing a hot-rolled steel plate for a high-strength hot-dip galvanized steel sheet, a method for manufacturing a cold-rolled steel plate for a high-strength hot-dip galvanized steel sheet, and a high-strength hot-dip galvanized steel sheet, the high-strength hot-dip galvanized steel sheet having exceptional molding properties, outer surface appearance, and plating adhesion. The Mn content is 2.00 to 10.00%. The concentration of solid-solution Mn within a depth of 5 μm from the steel plate surface is 1.50% by mass or less, and the value obtained by dividing the average Mn mass percentage in the residual austenite by the average Mn mass percentage in the ferrite is 2.0 or greater. A first heat treatment is performed for holding said sheet in a temperature range of 650 to 850°C for 600 to 21600 s while the steel plate surface is exposed in an atmosphere having an H2 concentration of 0.1 to 25.0 vol% and a dew point of −45 to 0°C, and a second heat treatment is performed for holding said sheet in a temperature range of 650 to 830°C for 20 to 900 s in an atmosphere having an H2 concentration of 0.05 to 25.0 vol% and a dew point of −10°C or less.
Inventors:
AOYAMA MAI (JP)
TANAKA MINORU (JP)
SUZUKI YOSHITSUGU (JP)
KAWASAKI YOSHIYASU (JP)
TAKAHASHI HIDEYUKI (JP)
TANAKA MINORU (JP)
SUZUKI YOSHITSUGU (JP)
KAWASAKI YOSHIYASU (JP)
TAKAHASHI HIDEYUKI (JP)
Application Number:
PCT/JP2016/004829
Publication Date:
June 01, 2017
Filing Date:
November 08, 2016
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C38/14; C22C38/60; C23C2/02; C23C2/06
Domestic Patent References:
| WO2015022778A1 | 2015-02-19 | |||
| WO2016067626A1 | 2016-05-06 |
Foreign References:
| JP2013076162A | 2013-04-25 | |||
| JP2008266778A | 2008-11-06 | |||
| JP2003277902A | 2003-10-02 |
Other References:
See also references of EP 3382049A4
Attorney, Agent or Firm:
KUMASAKA, Akira et al. (JP)
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