... of our company for the seamless steel pipe and welded steel pipe are divided into two categories ... SCH10-SCHXXX wall thickness. 1 general purpose of seamless steel pipe ASTM A53GR.B: SA53B, grades, specifications:1/ ... 4" -28", 13.7-711.2mm 3 line pipe steel API SPEC5L: B specifications: 1/ 4" -28", ... -28", 13.7-711.2mm 8 Steel seamless steel pipe (heat pipe) DIN17175-1979: carbon structural steel, steel ...