Title:
GALVANNEALED SHEET STEEL AND PROCESS FOR PRODUCTION THEREOF
Document Type and Number:
WIPO Patent Application WO/2006/112515
Kind Code:
A1
Abstract:
The invention aims at providing galvannealed sheet steel excellent in corrosion resistance, workability, coatability and appearance and a process for the production thereof. The invention relates to a process for the production of galvannealed sheet steel which comprises subjecting an ultra low carbon steel sheet to surface cleaning and preplating with nickel, heating the resulting sheet rapidly either in the absence of oxygen or in a reducing atmosphere to a sheet temperature of 430 to 500°C at a temperature rise rate of 30°C/sec or above, plating the sheet in a plating bath of molten Zn, wiping the resulting sheet, heating the sheet rapidly to 470 to 600°C at a temperature rise rate of 30°C/sec or above, and then cooling the sheet either without soaking or after soaking for less than 15 seconds. The galvannealed steel sheet produced by the process is composed of an ultra low carbon steel sheet and a galvannealed layer formed on at least one side of the sheet which layer comprises by mass Fe: 8 to 13 %, Ni: 0.05 to 1.0%, and Al: 0.15 to 1.5% with the balance being Zn and unavoidable impurities, and has an Al/Ni ratio of 0.5 to 5.0, the mean thickness of &Ggr layer present on the interface of basis steel being 1μm or below and the dispersion of the thickness falling within ± 0.3μm.
Inventors:
ISHIZUKA KIYOKAZU (JP)
NISHIMURA KAZUMI (JP)
KIKUCHI IKUO (JP)
MIYASAKA AKIHIRO (JP)
NISHIMURA KAZUMI (JP)
KIKUCHI IKUO (JP)
MIYASAKA AKIHIRO (JP)
Application Number:
PCT/JP2006/308369
Publication Date:
October 26, 2006
Filing Date:
April 14, 2006
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
ISHIZUKA KIYOKAZU (JP)
NISHIMURA KAZUMI (JP)
KIKUCHI IKUO (JP)
MIYASAKA AKIHIRO (JP)
ISHIZUKA KIYOKAZU (JP)
NISHIMURA KAZUMI (JP)
KIKUCHI IKUO (JP)
MIYASAKA AKIHIRO (JP)
International Classes:
C23C2/02; C23C2/06; C23C2/28
Foreign References:
| JPH073417A | 1995-01-06 | |||
| JPH11315360A | 1999-11-16 | |||
| JPH0734213A | 1995-02-03 |
Attorney, Agent or Firm:
Aoki, Atsushi (Toranomon 37 Mori Bldg. 5-1, Toranomon 3-chom, Minato-ku Tokyo 23, JP)
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