Effects of Local Heating on Material Flow in Free Forming Process

Abstract

A novel manufacturing method is investigated, in which a proper temperature gradient is created within workpiece in order to control local material flow during free forming. The main motivation is to produce complicated shapes by reducing the flow stress on the regions, where local deformation is desired to take place. A sufficient control of temperature within the material results in the required product shape even in the absence of complicated dies. Besides the lower tooling costs the process provides, the heat energy applied to the workpiece is less than that in conventional hot forming processes, which is currently a strong alternative for manufacturing of such products. In the study, heating is realized by means of induction heating and laser beam scanning. The process is investigated experimentally on circular cylinder specimens made of different materials, namely Ti6Al4V, X5CrNi18/9 and 16MnCr5. The effect of process parameters on the mode of deformation is analyzed by finite element method (FEM). The thermo-mechanical analysis of induction heating is supported by electromagnetic calculations. The two alternative heating methods are compared. Affects of heating on multiple locations is investigated for induction heating applications. A brief overview of the process is presented and conclusions are drawn on the effectiveness, limitations, failure modes and applicability of the process. Copyright © 2006 by ASME.