High-speed data acquisition of the cooling curves and evaluation of heat transfer coefficient in quenching process

The evaluation of surface heat transfer coefficients by using experiment measurement method is an inverse heat conduction problem. According to the characteristics of quenching process, a high-speed data acquisition system for measuring the temperature variations in a quenched part was set up by using industry standard architecture (ISA) in this paper. Cooling curves of P20 steel quenched in 20 °C and 60 °C water were acquired by using this system. A new method, which combines the finite element method (FEM) with optimization methods, was presented. The method can be used to evaluate the temperature-dependent surface heat transfer coefficient between the quenched part and quenchant in quenching process according to the temperature curve gained by experiment. In every time interval, the phase-transformation volume and the phase-transformation latent heat of every element are calculated by using FEM. The temperature and the phase-transformation volume of every element are calculated with the coupling calculation of phase-transformation latent heat.