Failure Analysis of Cold Extrusion Combination Concave Die and Numerical Simulation of Extrusion Process

The failure of cold extrusio n combination concave dies was observed through the experiment of screw cold extrusion forming.The results Indicate that the fatigue crack is the main failure form of the cold extrusion combination concave die and the crack occurrs mainly in the extrusion cone angle 45 and expands to outward.The cold extrusion process of screw was simulated by using DEFORM-2D.The stress distribution and change trend of the cold extrusion combination concave die were analyzed,the fatigue failure mechanism of the die was discussed.The simulation results give theoretical basis for improving and optimizing the structure of die.