Carbon Steel Pipe with High Quality 1.WT:4-70mm OD:25-370mm 2.Certification:API ... .53-40 Rectangular TubeQ195,Q235,Q345,20#GB/T6278-2002 Structure, decoration, construction20*20-500*500 ductile iron pipe-ironGB/ ... industryDN80-1500-square pipeQ195,Q235,Q345,20#GB/T6278-2002 Structure, decoration, construction20*20-500*500ASTM A53 GR.B Carbon ... A53 GR.B/A106 GR.B Carbon Steel Pipe with High Quality