The flange facing machine is a portable and efficient product. The machine is inside mounted in pipe or flange, and can process inner hole of the flange, the outer circle and various sealing surfaces (RF, RTJ, etc.). Modular design of the whole machine, easy to assemble and disassemble, equipped with preloaded braking system, intermittent cutting, unlimited working direction, high productivity and low noise, widely used in cast iron, alloy structural steel, stainless steel and other metal materials. Flange sealing surface repair, flange surface repair and etc.