Kawasaki Steel Corporation

The Furukawa Electric Co., Ltd.

Furukawa Aluminum Co., Ltd.

Naoki Nishiyama

Motohiro Nabae

Rinsei Ikeda

Koichi Hashiguchi

Nobuo Totsuka

Yoshihiro Matsumoto

Yasuji Uesugi

Masaaki Kurihara

Yoichiro Bekki

Takaaki Hira

Koji Yamato

Makoto Imanaka

Masaki Mabuchi

Kouichi Hashiguchi

An aluminum alloy sheet combining excellent press formability and spot weldability is disclosed. A chromate film of about 1.0 to 50.0 mg/m.sup.2 expressed in terms of metallic chromium is formed as a first layer on an aluminum alloy sheet, and an organic resin film containing about 60-95% by weight of organic lubricant and having a thickness of 0.02 to 0.90 .mu.m in terms of dry thickness is formed as a second layer on the chromate film. As the organic lubricant, a high-density polyethylene having a mean molecular weight of about 900 to 15,000 and a density of about 0.93 g/ml or more is preferable. This aluminum alloy sheet can be effectively used for automobile body applications.

Aluminum alloy sheet having excellent press formability and spot

A method including preparing an aluminum scrap containing a total of about 0.3 to 2.0 wt % of Fe and Si; melting and then adjusting the material composition so as to attain an Mg content of about 3 to 10 wt % or a composition further containing at least one of the elements Cu, Mn, Cr, Zr and Ti, each in the amount of 0.02 to 0.5 wt %; subjecting the material to casting, hot rolling, cold rolling and continuous annealing to obtain an aluminum alloy sheet having a tensile strength of about 31 kgf/mm.sup.2 or more; and applying a lubricant surface coating to impart a coefficient of friction of not more than about 0.11.

Method of producing an aluminum alloy sheet excelling in formability

A surface-treated aluminum material comprising an aluminum or aluminum alloy substrate, a chromate film deposited on the substrate, and an organic resin mixture film deposited on the chromate film is provided. The chromate film is deposited to a coating weight of from 5 to 100 mg/m.sup.2 calculated in terms of elementary chromium on the aluminum substrate. The organic resin mixture film is deposited to a dry film thickness of from 0.05 to 3.0 .mu.m, and comprises (a) 100 parts by weight of an organic resin, (b) 0.5 to 40 parts by weight of a powder lubricant having an average particle size of from 0.05 to 20 .mu.m, said average particle size being in the range of from 1.0 to 10 folds of the dry film thickness, and (c) 1.0 to 40 parts by weight of electroconductive finely divided particles having an average particle size in the range of from 0.05 to 5 .mu.m, said average particle size being in the range of from 1.0 to 2 folds of the dry film thickness. The organic surface-treated aluminum material has remarkable weldability, workability as well as corrosion resistance.

Surface-treated aluminum material having improved spot resistance

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Chiba, Japan

Naoki Nishiyama