... rolled galvanized steel pipe 1)Thickness:1.0-6.5mm 2)OD:20-168mm 3)Certification:ISO9001:20 GB/T3091galvanized steel pipe ... Details1.Product Name:GB/T3092-93 galvanized steel pipe 2.Place of Origin: ... Grinding, g.Lubrication, h. Cold rolling, i. Degreasing, j. Solution heat treatment, k. Straightening, l. Cutting, m. Pickling, n. Inspection ...