Hitachi, Ltd.

Hiromi Hieno

Kazuo Watanabe

Yuichi Kobayashi

Junichi Nagasawa

Toshiyuki Fukaya

Shoichi Kamiya

Using a chrome plating bath containing organic sulfonic acid, plating is conducted by application of a pulse current to thereby form a crack-free lower chrome layer on a steel substrate. The lower chrome layer has a compressive residual stress of 100 MPa or more and a crystal grain size of from 9 nm to less than 16 nm. Subsequently, by application of a direct current, a cracked upper chrome layer is formed on the lower chrome layer, to thereby obtain a chrome plated part. The lower chrome layer imparts the chrome plated part with heat resistance and corrosion resistance, and the upper chrome layer imparts the chrome plated part with wear resistance and good sliding properties.

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Gamagori, Japan

Hiromi Hieno