... ISO, API Seamless Steel Tubes for low and Medium Pressure BoilersSpecificationsChina StandardSteel GradeStandardseamless steel tubesGB/T8162-199910, 20 ... 5LA, B, X42APIoil casing andtubing in oil wellsSeamles Steel TubesGB5310-199520G, 20MnG, 25MnG, 15MoG, 20MoG, ... 15CrMo, 12Cr2MoISO 9329-2-1997 for high pressure --Chemical fertilizer equipmentASTM A161-94Seamless steel tubesGB9948-8610, 20, 12CrMo ...