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. 電縫鋼管の製造ラインに、多段に配置され、シームを溶接した鋼管を最終製品サイズにまで絞り圧延するサイザー圧延機の下流にめっき槽を設け、絞り圧延後の鋼管に溶融金属めっきを施す方法を改良した。 - 特許庁