... seamless steel tubes and transport liquid, gas, oil etc.Quality Standard:GB/T 8163: Seamless steel tubes for liquid serviceGB 3087: ... : SEAMLESS CIRCULAR TUBES OF NON ALLOY STEELS WITH SPECIAL QUALITY REQUIREMENTSDIN 17175: SEAMLESS STEEL TUBES FOR ELEVATED TEMPERATURESAPI 5L: ... 10#, 20#, 35#, 45#, 16MN(Q345B)GB 3087: 10#, 20#, 35#, 45#, 16MN(Q345B)GB 5310: 20G, 12Cr1MoV, 12Cr1MoVG, 12CrMoGASTM A106 ...