... certificate (2)iso9001 certificate (3)API 5Land API5CT certificate1> seamless steel pipe Size: OD 1/8 inch --14 inch, wall thickness ... precision cold drawn seamless steel pipe: OD20mm to 203mm,wall thickness:2mm to 30mmthe material are A53B,A106B,ST37,ST45,ST52,10#, 20#, ... 35#, 45# 40Cr, 16Mn, 20Cr,40Cr,35CrMo,42CrMo,12CrMoV,10CrMo910, 12Cr1MoV, 15CrMo etc.seamless steel pipe Main ...