| 摘要 |
PURPOSE:To provide the titled steel pipe which is inexpensive and sufficiently resistant to corrosion in cold and severe corrosive environments, by providing an underplated Zn-Ni alloy layer, in a steel pipe which is obtained by subjecting an electroplated Zn layer to a chromate treatment and is used for piping in a brake system of an automobile or the like. CONSTITUTION:An electroplated Zn-Ni alloy layer 3 preferably consisting of an alloy of 80-95% of Zn and 5-20% of Ni and having a thickness of 1-10mum is provided on the outer surface of a steel pipe 1 with or without an electroplated layer of copper or a copper alloy. Then, an electroplated Zn layer 4 consisting of pure Zn and having a thickness of 2-10mum is provided thereon, and finally a chromate layer 5 is provided.
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