... --for the general structure6-610×1-75 Fluid Pipe20,Q345GB/T8163-2008Fluid transport8-630×1.5-40 Precision Tube ... oil pipe for oil well, Coupling Cylinder60-630×1.53-40 Low and medium pressure boiler tube 10 ... plant-heat-exchanger tube- Pipeline seamless pipe10-530×1.5-36 high-pressure seamless pipe for chemical ... gas, industrial dilivery(gas,water,oil)60-630×1.53-40 Rectangular TubeQ195,Q235,Q345,20#GB/ ...