... galvanized steel pipe 1)Thickness:1.0-6.5mm 2)OD:20-168mm 3)Certification:ISO9001:20 GB/T3091galvanized ... of Origin:Tianjin, China.3.Nominal Diameter:1/2,3/4,1,1-1/4,1-1/2,2,2-1/2,3,4,5 ... -1985 DIN2244 GB3091-93 10.Grade10#,20#,45#,A53(A,B),Q195,Q215,Q235 11.Production:Has the following ... production steps:a. Round preparation, b. Heating, c. Hot perforation, d. ...