| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyethylene-coated steel pipe having excellent cathode peeling resistance of a resin-coated layer and enabling production without a chromate treatment.SOLUTION: A steel pipe includes a surface-treated layer formed with an aqueous surface treatment agent comprising (A) a required amount of silica, (B) aluminum phosphate, (C) titanium peroxide, (D) an organic phosphonic acid compound, (E) zirconium ammonium carbonate, (H) a silane coupling agent having an epoxy group as an organic functional group and, if necessary, (F) a required amount of zirconium ammonium fluoride and/or (G) a required amount of ammonium metavanadate and also has an epoxy primer resin layer, an adhesive polyethylene resin layer, and polyethylene resin layer, in this order, on the surface-treated layer. |
