Experimental and Numerical Parameter Studies on Plane-Strain Backward Extrusion

The present paper is concerned with the experimental and numerical studies on the effects of some process variables on the forming load and product uniformity in the plane-strain backward extrusion operation. At first, several extrusion experiments were conducted with linear dies, various extrusion ratios and bar sizes. Then the finite-element simulations of these tests were performed. After attaining good correlations between the numerical and experimental results, further numerical analyses were carried out in order to investigate the influences of other types of die shapes, namely the exponential and the second-order polynomial profiles. It was found that the later profile, compared with the linear and exponential profiles, involved the minimum load and energy requirements and higher uniformity for the product. After observing the distributions of the effective strain in the product and deformation zone, it was found that these benefits were achieved because the second-order polynomial profile induced smaller redundant work and strain in the process.