... 1/4"-24" Certificate: ISO, API Seamless Steel Tubes for low and Medium Pressure BoilersSpecificationsChina StandardSteel GradeStandardseamless ... SPEC 5LA, B, X42APIoil casing andtubing in oil wellsSeamles Steel TubesGB5310-199520G, 20MnG, 25MnG, 15MoG, 20MoG, 12Cr1MoVG, ... A192for low and Medium Pressure BoilersASTM SA179,SA192, BS3059Seamless Steel TubesGB6479-8610, 20G, Q345, Q390, 10MoVNb, 12CrMo, ...