Research on the destabilization of the ejector rod of cold header

Abstract

Taking the ejector rod of a series of long bolts on cold heading process as the research object, the force of ejector rod is simulated and analyzed by DEFORM-3D software in order to solve the problem of ejector rod fracture encountered with actual production. The buckling of ejector rod is analyzed by Workbench software, and the relationship between the stress of M6 outer hexagon longs bolt ejector rod with different length-diameter ratios of cold heading and the critical stress of destabilization is analyzed. The critical length-diameter ratio of the ejector rod to break with unprotected condition is obtained, which agrees with the production experience of an enterprise. The finite element analysis technology provides theoretical basis of the production of long bolts and provides standard for the design of cold heading ejection mechanism.