Sumitomo Metal Industries, Inc.

Sumitomo Light Metal Industries, Ltd.

Masanori Tsuji

Yoshihiko Hoboh

Kazuyuki Fujita

Naotaka Ueda

Masanari Kimoto

Hiroshi Ikeda

Tetsuaki Tsuda

Kiyoyuki Fukui

Keizo Namba

Hiroshi Oishi

Seiji Bando

Hisao Yoshimori

Takao Aimu

Hideyuki Uto

A plated aluminum sheet has improved spot weldability and press-formability and is suitable for use in the manufacture of automobile bodies. The aluminum sheet has a plated coating of a metal having a melting point of about 700.degree. C. or above, e.g., Cr, Mn, Fe, Co, or Ni, an alloy of two or more of these metals, or a Zn alloy with at least one of these metals, on one or both surfaces thereof.

Plated aluminum sheet having improved spot weldability

An aluminum sheet for use in spot welding has an anodic oxide film with a thickness of 50 .mu.m or less on at least one surface thereof. The anodic oxide film is preferably overlaid with a plating layer predominantly comprising at least one metal selected from the group consisting of Zn, Cr, Co, Ni, Fe, and Mn. The aluminum sheet can be produced by subjecting an aluminum or aluminum alloy sheet to anodic oxidation in an acidic solution having a pH of 4 or less conditions of from 2 to 200 V in voltage and from 0.2 to 200 seconds in duration, optionally followed by electroplating in an acidic plating bath.

Spot-weldable aluminum sheet and production thereof

A multilayer plated aluminum sheet suitable for use in automobile body panels comprises a base aluminum sheet made of aluminum or an aluminum alloy and has a first layer of zinc or a zinc alloy formed by displacement plating on the surface of the aluminum sheet and one or more layers of electroplated coating formed on the first layer by electroplating in an acidic bath. Preferably, the upper electroplated coating comprises at least one layer of zinc or a zinc alloy and the uppermost layer of the coating is formed from a metallic material having a melting point above 500.degree. C.

Multilayer plated aluminum sheets

A process for zinc electroplating of aluminum strip which can be performed continuously at a high speed and a high current density. The process comprises subjecting aluminum strip to anodic electrolysis in an acidic solution which may be an acidic plating bath solution or a pickling solution before the strip is subjected to cathodic electrolysis in an acidic zinc plating bath to perform zinc electroplating.

Process for zinc electroplating of aluminum strip

A process for direct zinc electroplating of aluminum strip which can be performed continuously at a high speed and a high current density. The process comprises pretreating aluminum strip by alkaline degreasing and then pickling and subjecting the pretreated aluminum strip to zinc electroplating in an acidic zinc plating bath which contains, in addition to Zn.sup.2+ ions, metal ions selected from the group consisting of Ni.sup.2+ ions and Fe.sup.2+ ions in a concentration of at least about 10 g/1 to form a Zn-Ni, Zn-Fe, or Zn-Ni-Fe alloy plated coating, which may be overlaid with another zinc electroplated coating.

Process for direct zinc electroplating of aluminum strip

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Wakayama, Japan

Masanori Tsuji