Estimation of interface heat transfer coefficient of ultra high strength steels in hot forming

To evaluate the interface heat transfer intensity during hot stamping process of ultra high strength steel,the numerical integration form of heat balance equation was proposed to calculate the IHTC in this study on the basis of experiment measured temperature curves,and the martensitic phase transformation was taken into consideration by means of equivalent heat capacity in the process of solving.The results show that the IHTC not only depend on working pressure,but also depend on temperature of materials.Finally,effectiveness of applied experimental and estimation method is verified by bringing the calculated IHTC into FEM software,and simulation results are in good agreement with experimental data.