Punch

In order to solve the technical problem that a rivet joint is cracked in the process of punching and riveting the rivet joint by a conventional punch, the utility model provides a punch which is used for punching the rivet joint, at least one end of the rivet joint is provided with a punching hole surrounded by the peripheral wall of the rivet joint, and the punch comprises a punch main body and a plurality of punching holes, one end face of the punch body is recessed inwards, a limiting part is arranged on the edge of the end face of the punch body, a punching concave face is defined by the limiting part and comprises a round face and a plurality of arc faces extending outwards from the round face, and the arc faces are connected end to end. And the expanding part is connected with the circular surface, is convexly arranged on the circular surface, and is used for extending into the punched hole and expanding the peripheral wall towards the periphery in the punching process, so that the peripheral wall exten