Heat and corrosion resistant steel pipe having multi-layered coating

Abstract

A heat and corrosion resistant steel pipe having multi-layered coating comprising a steel pipe, a Zn-Ni alloy plating layer deposited to the outer surface of the steel pipe and a polyvinyl fluoride layer formed on the Zn-Ni alloy plating layer with an epoxy resin being intervened therebetween as an intermediate layer. A metal plating layer comprising Zn-Ni plating layer and Ni-plating layer may be used instead of the Zn-Ni plating layer. A chromate layer may be formed on the metal plating layer.

Description

[0001] 1. Field of the Invention

[0002] The present invention concerns a pipe of relatively small outer diameter such as less than about 20 mm disposed as a fluid transportation pathway to automobiles or like outer various machineries and, more in particular, it relates to a heat and corrosion resistant steel pipe having multi-layered coating with a protection layer capable of withstanding severe corrosive circumstance.

[0003] 2. Description of the Prior Art

[0004] As pipeways used for automobiles or other machineries, those products having Zn-plating layer formed to the outer surface of a steel pipe and applied with chromate treatment to the Zn-plating layer have generally been used.

[0005] However, working conditions are severe, for example, in braking or fuel pipeways of automobiles and there have been demands for heat resistance under high temperature circumstance such as at the periphery of engines, resistance to external mechanical forces such as scratch resistance and impact shoc...

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