Title:
HOT-DIP GALVANIZED STEEL SHEET, ALLOYED HOT-DIP GALVANIZED STEEL SHEET AND PRODUCTION METHODS THEREFOR
Document Type and Number:
Japanese Patent JP2017048412
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet each of which has good elongation property and bendability, and production methods therefor.SOLUTION: The hot-dip galvanized steel sheet is provided which comprises a steel sheet and a hot-dip galvanized layer, and in which the steel sheet includes a base material and a decarbonized ferrite layer, structure at a position of 1/4 depth of sheet thickness of the steel sheet contains 5.0 vol.% or more of tempered martensite and 0.5 vol.% or more and less than 7.0 vol.% of retained austenite and the balance mainly composed of 4 to 70 vol.% of ferrite and bainite, a part or all of the tempered martensite and retained austenite form M-A (Martensite-Austenite constituent), the decarbonized ferrite layer contains 120% or more of ferrite based on content of ferrite at depth of 1/4 of the sheet thickness, has ferrite average crystal particle diameter of 20 μm or less and a thickness of 5 μm to 200 μm, the structure of the decarbonized ferrite layer contains 1.0 vol.% or more of the tempered martensite and number density of the tempered martensite in the decarbonized ferrite layer is 0.01/μmor more.SELECTED DRAWING: Figure 1
Inventors:
HAYASHI KOTARO
HAGA JUN
KAWADA HIROYUKI
SANO KOICHI
UENISHI AKIHIRO
HAGA JUN
KAWADA HIROYUKI
SANO KOICHI
UENISHI AKIHIRO
Application Number:
JP2015170772A
Publication Date:
March 09, 2017
Filing Date:
August 31, 2015
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP
International Classes:
C22C38/00; C21D9/46; C22C38/58; C23C2/40
Domestic Patent References:
| JP2013144830A | 2013-07-25 |
Foreign References:
| WO2013047760A1 | 2013-04-04 | |||
| US20140234659A1 | 2014-08-21 | |||
| WO2013047755A1 | 2013-04-04 | |||
| US20140227555A1 | 2014-08-14 | |||
| WO2013118679A1 | 2013-08-15 | |||
| US20140377582A1 | 2014-12-25 | |||
| WO2016171237A1 | 2016-10-27 |
Attorney, Agent or Firm:
Masatake Shiga
Mitsuo Teramoto
Sumio Tanai
Tomoo Katsumata
Hiroshi Yamaguchi
Mitsuo Teramoto
Sumio Tanai
Tomoo Katsumata
Hiroshi Yamaguchi
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