Polishing machine with round stepped polishing tool

The utility model discloses metal processing equipment, particularly a polishing machine with round stepped polishing tools used for weld joint finishing. A piston (3) is movably arranged inside a cylinder body (4), a work piece (1) is arranged inside a small-diameter inner bore at the left end of the piston (3) and movably connected with a magnet ejector rod (5), and a combined polishing tool (2) is arranged inside a large-diameter inner bore (8) at the left end of a piston (7) and movably connected with a weld joint (6) at the left end of the work piece (1). With the arrangement of the combined round stepped polishing tool, when polishing the work piece, the acting force on the stepped polishing tools is 1/10 to 1/20 that of the whole round stepped polishing tool, thereby increasing the efficiency of polishing the weld joint of the round thin-wall work piece. The utility model can not only increase the work efficiency, but also prevent the damage to the work piece.