... /4"-24" Thickness: 2mm-60mm Certificate: ISO,API material:carbon steel API 5L carbon steel pipeline SpecificationsChina StandardSteel GradeStandardseamless steel tubesGB/T8162-199910 ... steel tubes forAPE SPEC 5LA, B, X42APIoil casing andtubing in oil wellsSeamles Steel TubesGB5310-199520G, 20MnG, 25MnG, 15MoG, 20MoG, 12Cr1MoVG, 15CrMoVG ...