Research on rolling-extrusion forming of variable wall thickness cylinder parts

摘要

The rolling-extrusion technique for the mass production of variable wall thickness cylinder parts is put forward to reduce the machining time and increase the material utilisation. In this process, material is formed by means of three passive rotational tools. The charge is provided by means of a pusher pushing the billet in a working space between the profiled rolls. A coupled thermalmechanical rigid viscoplasticity FEM model for rolling-extrusion of variable wall thickness cylinder parts is developed based on the DEFORM-3D software. Then the distribution of effective strain field, temperature filed and the load during the rolling-extrusion forming process are discussed. Moreover, the influence of process parameters on the deformation uniformity is analysed, and the results show that the deformation non-uniformity of billet increases with increasing punch speed and friction factor or decreasing initial temperature of billet. In physical experiment, the press machine and a simple machine for rolling-extrusion are used to work out the parts. The results of these tests show the parts can be produced accurately by using rolling-extrusion technique. Compared with the traditional method, the material utilisation is increased by 19% with the machining time greatly reduced.