The interfacial heat transfer coefficient in hot die forging of titanium alloy

An investigation of die temperature changes and the heat transfer coefficient during hot forging of titanium alloy has been carried out using experiments and a thermal-plastic coupled finite element analysis. Hot Ti-6Al-4V rings were forged between two heated Aat dies made of Inconel alloy IN718. The bottom die was instrumented with high-response thermocouples on its surface and subsurface. The recorded temperatures were analysed and used to determine the interface heat transfer coefficient between the die and the workpiece in conjunction with the thermal-plastic coupled finite element analysis using a reverse algorithm. The coefficients determined were then used in a finite element model for the analysis of the upsetting process and the results produced were in good agreement with the experimental data.