Research On Control Strategy Of Variable Thickness Disk Gas Quenching Process Based On Distributed Parameter Model

It is an available approach to enhance the mechanical and chemical properties of metal by using a more efficient quenching process. Nowadays the quenching methods of industry can be divided into several categories by quenching medium, such as water quenching, oil quenching, gas quenching, etc. Gas quenching among those methods is a proper way which can reduce the material internal structure stress and has a higher quenching speed. In this paper, the effect of air gas quenching of disk with variable thickness was discussed based on a new type of gas quenching device. The better technology parameters for internal temperature uniformity and crystal phase while quenching disk with several shape features were obtained by means of controlling gas velocity.This paper revealed numerical simulation research on air gas quenching process of disk; simplified turbulence equations and studied heat transfer parameters of disk surface. Turbulence model of simulation was verified by a dimensionless distance of the first layer cell adjacent to disk surface. Nu number of disk surface on different regions was analyzed and the relations between average Nu number and Re number were revealed.In order to obtain the ideal temperature during quenching process, corresponding nozzles must control their gas velocity with time. Aimed at this inverse problem, closedloop control system of FLUENT and Simulink co-simulation was designed and the velocity data was obtained via this system. The internal points’ temperature of disk based on the distributed parameter model was under control accurately using this method. While the closed-loop control model designing, traditional fuzzy control and other control policies were changed according to the long time-delay, inertia and coupling characteristics of the disk. Finally the real time velocity data of corresponding nozzles were obtained. The control strategy, in this paper, can optimize the traditional quenching process and improve the mechanical properties of disk.Experiments of the variable thickness disk were done using this device. Temperature of some internal monitoring points was extracted, and the regular of temperature dropping was analyzed. Compared with these points’ temperature obtained by simulation, the temperature downtrend and deviation were analyzed.