METHOD FOR HOT-DIP METAL PLATING ELECTRIC RESISTANCE WELDED STEEL PIPE

PROBLEM TO BE SOLVED: To provide a method for hot-dip galvanizing an electric resistance welded steel pipe, which quickly forms not only a thick plated layer with a large coating weight on-line but also a uniform plated layer. SOLUTION: The line for manufacturing the electric resistance welded steel pipe comprises: a sizer rolling mill which is arranged in a multistage form, and squeezingly rolls a steel pipe having a welded seam into a final product size; and a plating tank which is placed in the downstream of the sizer rolling mill, and in which the squeeze-rolled steel pipe is hot-dip metal plated. The hot-dip metal plating method is an improved plating method using the above line, and comprises the steps of: squeezingly rolling the steel pipe with a roll having protrusions on its surface, which is arranged on a roll stand in a last stage, or with similar rolls arranged on two roll stand in the last stage and the preceding stage to form fine indentations on the outer surface of the steel pipe; and immersing the steel pipe into the plating tank. COPYRIGHT: (C)2007,JPO&INPIT