Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Patent
1994-12-19
1997-05-13
Zimmerman, John
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
428687, 428939, 148242, 148533, 148534, B32B 1518, C23C 206, C23C 228
Patent
active
056290993
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an alloying-treated iron-zinc alloy dip-plated steel sheet excellent in press-formability and a method for manufacturing same.
BACKGROUND OF THE INVENTION
Alloying-treated iron-zinc alloy dip-plated steel sheets and zinciferous electroplated steel sheets have conventionally been used as outer shells for an automobile body, a home electric appliance and furniture. Recently, however, the alloying-treated iron-zinc dip-plated steel sheet is attracting greater general attention than the zinciferous electroplated steel sheet for the following reasons:
(1) The zinciferous electroplated steel sheet having a relatively small plating weight, manufactured usually by subjecting a cold-rolled steel sheet having an adjusted surface roughness to a zinc electroplating treatment, is preferably employed as a steel sheet required to be excellent in finish appearance after painting and in corrosion resistance such as a steel sheet for an automobile body;
(2) However, the steel sheet for an automobile body is required to exhibit a further excellent corrosion resistance;
(3) In order to impart a further excellent corrosion resistance to the above-mentioned zinciferous electroplated steel sheet, it is necessary to increase a plating weight thereof, and the plating weight thus increased leads to a higher manufacturing cost of the zinciferous electroplated steel sheet; and
(4) On the other hand, the alloying-treated iron-zinc alloy dip-plated steel sheet is excellent in electro-paintability, weldability and corrosion resistance, and furthermore, it is relatively easy to increase a plating weight thereof.
However, in the above-mentioned conventional alloying-treated iron-zinc alloy dip-plated steel sheet, the difference in an iron content between the surface portion and the inner portion of the alloying-treated iron-zinc alloy dip-plating layer becomes larger according as the plating weight increases, because the alloying treatment is accomplished through the thermal diffusion. More specifically, a .GAMMA.-phase having a high iron content tends to be easily produced on the interface between the alloying-treated iron-zinc alloy dip-plating layer and the steel sheet, and a .zeta.-phase having a low iron content is easily produced, on the other hand, in the surface portion of the alloying-treated iron-zinc alloy dip-plating layer. The .GAMMA.-phase is more brittle as compared with the .zeta.-phase. In the alloying-treated iron-zinc alloy dip-plating layer which has a structure comprising the .GAMMA.-phase and a structure comprising the .zeta.-phase, a high amount of the .GAMMA.-phase results in breakage of the brittle .GAMMA.-phase during the press-forming, which leads to a powdery peeloff of the plating layer and to a powdering phenomenon. When the .zeta.-phase is present in the surface portion of the alloying-treated iron-zinc alloy dip-plating layer, on the other hand, the .zeta.-phase structure adheres to a die during the press-forming because the .zeta.-phase has a relatively low melting point, leading to a higher sliding resistance, and this poses a problem of the occurrence of die galling or press cracking.
In the above-mentioned conventional alloying-treated iron-zinc alloy dip-plated steel sheet, particularly in an alloying-treated iron-zinc alloy dip-plated steel sheet having a large plating weight, furthermore, an effect of improving image clarity after painting of the alloying-treated iron-zinc alloy dip-plated steel sheet cannot be expected from adjustment of surface roughness of the steel sheet before a zinc dip-plating treatment.
Various methods have therefore been proposed to improve press-formability and/or image clarity after painting of an alloying-treated iron-zinc alloy dip-plated steel sheet.
Japanese Patent Provisional Publication No. 4-358 discloses a method for improving press-formability of an alloying-treated iron-zinc alloy dip-plated steel sheet by applying any of various high-viscosity rust-preventive oils and solid lubricants onto a surface of
REFERENCES:
patent: 3190768 (1965-06-01), Wright
patent: 4059711 (1977-11-01), Mino et al.
patent: 5049453 (1991-09-01), Suemitsu et al.
patent: 5316652 (1994-05-01), Sagiyama et al.
patent: 5409533 (1995-04-01), Sagiyama et al.
M. Urai et al., "Effect of Aluminum on Powdering Characteristics of Galvannealed Steel Sheet", Galvatech, 1989, pp. 478-485.
Y. Hisamatsu, "Science and Technology of Zinc and Zinc Alloy Coated Steel Sheet", Galvatech, 1989, pp. 3-12.
Patent Abstracts of Japan, vol. 12, No. 242 (C510), 8 Jul. 1988 of JP-A-63 033591 (Kawasaki Steel), 13 Feb. 1988.
Patent Abstracts of Japan, vol. 9, No. 228 (C-303), 13 Sep. 1985 of JP-A-60 086257 (Kawasaki Steel), 15 May 1985.
Inagaki Jun-ichi
Sakurai Michitaka
Tahara Kenji
Watanabe Toyofumi
NKK Corporation
Zimmerman John
LandOfFree
Alloying-treated iron-zinc alloy dip-plated steel sheet excellen does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Alloying-treated iron-zinc alloy dip-plated steel sheet excellen, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alloying-treated iron-zinc alloy dip-plated steel sheet excellen will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1383817