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An Application of Computer Simulation in Optimization of Quenching and Tempering of Steel Workpiece

The method of computer simulation of yield strength, fracture toughness and fatigue resistance has been applied in analysis of a quenching and tempering of steel workpiece. Two options of steel workpiece manufacturing were analyzed. First option gives opportunity to quench and temper suitable shaped workpiece, and in second option steel workpiece was manufactured from quenched and tempered steel bar of diameter equal to maximal diameter of analyzed workpiece. The algorithm of estimation of yield strength and fracture tough-ness was based on steel hardness, HV. Numerical modelling of hardness distribution in quenched and tempered steel has been performed based on time of cooling from 800 °C to 500 °C (t8/5) and by involving the results of simple experimental test, i.e., Jominy-test. The time of cooling at specimen point was predicted by numerical simulation using the finite volume method. Yield strength and fracture toughness distributions have been predicted using the Hahn-Rosenfield approach. Fatigue threshold was estimated based on predicted microstructure and hardness. Mathematical model of microstructure composition in quenched steel has been based on cooling time, t8/5 during the quenching. The better mechanical properties were achieved by quenching and tempering of workpiece with appropriate shape.

heat treatment; computer simulation; microstructure; yield strength; fracture toughness; fatigue resistance

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