... , seamless steel pipes for pipelineHigh-pressureSeamless pipes for fertilizer making equipment20, 16Mn,Q345GB6479-200018-530*3-40Fertilizer making equipment and pipe lineLow and medium- pressure ... ,20GB3087-199910-530*2-40Over-heat pipe for low and medium pressure boiler, boiling water pipe, locomotive smoke pipe(big and small)Fluid pipe20, Q345GB/T8163-19998 ...