engleski

Computer modeling of mechanical properties and microsructure of quenched steel specimen

The research purpose is to upgrade the mathematical modeling and computer simulation of quenching of steel. Based on theoretical analyze of physical processes which exist in quenching systems the proper mathematical model is established and computer software is developed. On the basis of control volume method, the algorithm for prediction of mechanical properties and microstructure distribution in quenched steel specimens with complex geometries has been developed. The computer simulation of steel hardening is consisted of numerical calculation of transient temperature field in process of cooling, and of numerical calculation of mechanical properties. The hardness has been predicted by the conversion of calculated time of cooling from 800 to 500 °C at specimen points to the hardness. Conversion of cooling time results to the hardness was done based on Jominy hardenability curve. Other mechanical properties can be predicted based on hardness results. Physical properties that were included in the model, such as heat conductivity coefficient, heat capacity and surface heat transfer coefficient were obtained by the calibration. The established method in efficient approach combines not expensive experimental Jominy test with computer modeling of transient temperature field in prediction of mechanical properties and behavior of steel during the quenching. The algorithm is completed to solve 3- D situation problems such as the quenching of complex cylinders, cones, spheres, etc. The established model of steel quenching can be successfully applied in the practice of heat treatment.

Steel; quenching; computer modelling; microstructure; mechanical properties; die component

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