Sumitomo Metal Industries, Inc.

Tadashi Nonaka

Yoshihiko Hoboh

Tatsuo Kurimoto

Nobukazu Suzuki

Atsuhisa Yakawa

Hiroshi Oishi

Yasuo Shimada

Kazuhide Oshima

Yoshikazu Yamanaka

Tomio Kondo

Hisakazu Morino

Steel plate for automobile bodies and a method for manufacturing the steel plate are disclosed, the steel plate containing 0.02.about.0.03% of P as an alloying element with a total amount of Cu, Ni, Cr, and Mo being more than 0. 01% but less than 0.08 weight % and being electroplated with a Zn alloy.

Steel plate for the outside of automobile bodies electroplated with a

A continuous multi-layer plating line for steel sheet which includes a hot-galvanizing apparatus to form a galvanized coating and optionally to alloy the coating and an electroplating apparatus to form an electroplated coating on the galvanized coating. Between the hot-galvanizing apparatus and the electroplating apparatus, a post-galvanizing surface treatment apparatus effective for removing surface oxide contaminants and activating the surface of the galvanized coating is disposed and the galvanized steel sheet is treated thereby prior to electroplating. The post-galvanizing surface treatment may be carried out by applying an alkali solution or an acid which can dissolve aluminum oxide to the galvanized coating, by alkali electrolysis, by cathodic electrolysis, by cooling the galvanized steel sheet with an alkali solution, or by skin-pass rolling using an alkali solution or an acid which can dissolve aluminum oxide as a skin-pass roling liquid.

Electroplating of hot-galvanized steel sheet and continuous plating line

Steel plate for automobile bodies and a method for manufacturing the steel plate are disclosed, the steel plate containing 0.02.about.0.03% of P as an alloying element with a total amount of Cu, Ni, Cr, and Mo being more than 0.01% but less than 0.08 weight % and being electroplated with a Zn alloy.

A Pb alloy insoluble anode and continuous electroplating of zinc using the same are disclosed, in which the Pb alloy consists essentially of 0.5-13 weight % of In or 0.5-13 weight % of In and 0.5-10 weight % of Ag and a balance of Pb with incidental impurities in which the amount of Sn is restricted to not more than 0.005% is used as an insoluble anode, and plating is carried out with a current density of at least 50 A/dm.sup.2 and a plating solution flow velocity of at least 0.6 m/sec.

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Wakayama, Japan

Tadashi Nonaka