Numerical Simulation And Research Of Heat Conduction Of Atomizing Gas Quenching Process

With the rapid development of modern machinery manufacturing industry,the requirements of heat treatment for metal materials become more and more complex,and the traditional quenching can not fully satisfy the demand of manufacturing improvement,so there is an urgent need to find some novel quenching method. Atomization gas quenching is just a new heat treatment process, Atomizing gas is used as cooling medium for rapid cooling treatment on the specimen during the quenching process, strong controllability, uniform cooling, cooling rate can be adjusted over a wide range and no pollution are the advantages of atomizing gas quenching cooling technology.However, because of a late start, atomizing gas quenching is still at the experimental research stage.First of all, according to the finite difference principle and quenching heat transfer basic principle, mathematical model relevant to heat conduction of atomization gas quenching was established,then the nonlinear finite difference heat conduction equations were derived in this paper.Secondly, The reverse thinking of integrated surface heat transfer coefficient of atomization gas quenching was proposed basing on finite difference nonlinear heat conduction equations and nonlinear iteration method.after that, the inverse program of the synthetic surface heat transfer coefficient during atomization gas quenching was written by the Matlab software.Then the surface integrated heat transfer coefficient corresponding to different process parameters are numerical calculated by the inverse program. The results show that the gas pressure and liquid content of atomization gas quenching medium all affect the heat transfer coefficient, the effects of liquid content are more obvious.The integrated surface heat transfer coefficient was substituted into the atomization gas quenching boundary conditions in succession,and the internal temperature field of specimen corresponding to different working conditions during atomization gas quenching were numerical simulated. The results show that the gas pressure and liquid content of quenching medium all affect the cooling speed of every internal node in specimens, the effects of liquid content are more obvious.Lastly, the experiment of atomizing gas quenching was designed and relevant experimental data have been collected in this paper.Then the calculated value and the measured value of specimen center temperature during atomizing gas quenching were compared to verify the accuracy of numerical simulation. Verification results show that the numerical simulation of heat transfer during atomizing gas quenching process is accurate and effective.