... and Cold DrowingSurface treatmentTransparent oil or black painting anti-corrosionPlace of originTianjinStandardBS, JIS, GB, DIN, ASTM, APIApplication Natural gas, petroleum, chemical ... , Cr5Mo, Cr9Mo GB9948-8810-530*1.5-36Boiler pipes for refinery,heatexchangeing pipes,seamless steel pipes for pipelineHigh-pressureSeamless pipes for fertilizer making equipment20, 16Mn,Q345GB6479-200018-530*3 ...