Abstract: A method of forming coatings in coated tubular metal members which comprises coating a fluoro resin on a chromate layer of a tubular metal member previously applied with Zn-plating having such chromate layer at the outer circumferential surface; coating a primer to the coating surface of the fluoro resin; depositing a heat shrinkable tubular member or applying a sol lining treatment of a vinyl chloride resin to the coated primer layer; forming a layer by heat shrinking the tubular member by applying heat treatment or by completely geling the sol lining, thereby tightly adhering and laminating them.

Abstract: A seam welded steel pipe proofed against corrosion and prevented from oxidizing a fluid such as gasoline to be passed therethrough is produced by a process comprising forming an Ni layer by electroplating on at least one of the opposite surfaces of a steel strip, abutting the opposite edges of said steel strip in the direction of width with the Ni layer on the inside and fusing the abutted edges, subjecting the resultant steel pipe to a heat treatment in an oxidizing atmosphere thereby forming an oxide coating on the surface of the Ni layer, acid dipping the resultant steel pipe thereby removing the oxide coating from the portion of the skin of steel exposed in the neighborhood of a bead part in consequence of the fusion, and introducing a chemical Ni plating liquid through the interior of the steel pipe thereby coating the inner surface in the neighborhood of the bead part with a Ni alloy layer by chemical plating.