... 3-114.3mm 3)Application:Structure 4)Certification:ISO9001:2000 Hot-dip Galvanized steel pipe 1)Thickness:2.77-6.02mm ... )Application:Structure 4)Certification:ISO9001:20001)Product Name:ASTM A53 Hot-dip Galvanized steel pipe2)Place of Origin:Nantong China(Mainland ... the following production steps:a. Round preparation, b. Heating, c. Hot perforation, d. Cutting head, e. Pickling, f. Grinding, g. ...