COATED STEEL PIPE

PROBLEM TO BE SOLVED: To provide a coated steel pipe wherein even in a wet environment, the adhesiveness of coating is not lowered so that excellent corrosion resistance can be obtained by superposing an ethylene-methacrylic aid copolymer layer on the undercoated inner or outer surface of a steel pipe through an epoxy primer layer. SOLUTION: An ethylene-methacrylic acid copolymer layer 3 is superposed on the undercoated inner or outer surface of a steel pipe 1 through an epoxy primer layer 2. As the steel pipe, a carbon steel pipe, stainless steel pipe or a clad-steel pipe wherein various kinds of metals or alloys are stacked on the inner or outer surface of a steel pipe can be used. And a steel pipe whose inner or outer surface is plated with various metals or alloys can be used. For undercoating, oil is removed from a surface of a steel pipe by degreasing and scales are removed by a blasting or pickling. As an epoxy primer, for example, a mixture comprising an epoxy, pigment, and curing agent is used, and the thickness of the layer is preferably 30-250 μm. And the thickness of the ethylene-methacrylic acid copolymer layer may be 0.5-8 mm.