THE INTERFACIAL HEAT-TRANSFER COEFFICIENT IN HOT DIE FORGING OF TITANIUM-ALLOY

An investigation of die temperature changes and the heat transfer coef ficient during hot forging of titanium alloy has been carried out usin g experiments and a thermal-plastic coupled finite element analysis. H ot Ti-6Al-4V rings were forged between two heated Aat dies made of Inc onel alloy IN718. The bottom die was instrumented with high-response t hermocouples on its surface and subsurface. The recorded temperatures were analysed and used to determine the interface heat transfer coeffi cient between the die and the workpiece in conjunction with the therma l-plastic coupled finite element analysis using a reverse algorithm. T he coefficients determined were then used in a finite element model fo r the analysis of the upsetting process and the results produced were in good agreement with the experimental data.