A method of measurement for determination of relative density in the axisymmetric forming of sintered porous material

Abstract

A new method for the determination of relative density is proposed in this work. Density is one of the most important variables in the forming of sintered porous materials. In the proposed method, the distribution of relative density is obtained experimentally from the grid patterns of the deformed specimen. The nodal coordinates and the tangential slopes of the end-points of each segment of a grid element are measured by use of an optical projector. The measured data are curve-fitted using an appropriate interpolating equation, the relative density then being obtained by means of numerical integration on the basis of mass conservation. The validity of the proposed method is checked for the axisymmetric forward extrusion process through a curved die. The indirectly measured values of relative density distribution are compared with those obtained by the rigid-plastic finite-element method, the comparison showing that there is a good agreement between the two results considering the numerical errors involved in the two methods. It is thus shown that the proposed method can be utilized further in other forming processes for sintered materials. © 1992.