OD: 38mm-325mm WT:4.5mm-45mm Grades:20G,20MnG,25MnG,15MoG,20MoG,12CrMoG,15CrMoG,12Cr2MoG,12CrMoVG,12Cr3MoVSiTiB,etc OD: 38mm-325mmWT:4.5mm-45mmStandard: GB5310-1999Grades:20G,20MnG,25MnG,15MoG,20MoG,12CrMoG,15CrMoG,12Cr2MoG,12CrMoVG,12Cr3MoVSiTiB,etc seamless steel pipe