UND fixed rail flash but welding machine belong to automatic flash welding equipment, composed of machine body, hydraulic clamp equipment, hydraulic compact structure, hydraulic central equipment, hydraulic slag remover, hydraulic slag block equipment, hydraulic pump station, constant temperature cold system, and CNC system. This machine adopts Japanese PLC control, realizing digital control, digital adjustment of program work time & work current, and network voltage compensation. It is the best electric control system, and it is the perfect special equipment which can instead of import equipment.