Weld Pipe 1.Standard:BS,ASTM,GB/T,API,ISOR65 2.Material:Q195-Q345,X42,X60,X65,X70 3. ... .3mmStandard GB/T3091 .BS1387-85 .ASTM A53, A500,A252,A795 ,API 5L PSL1/PSL2,ISOR65Out diameter 21.3-609.6mmMain Markets ... . 2,Special design can according to requirements. black erw welded pipes/tubes