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Prediction of working stress of quenched and tempered steel and cast steel specimen

In this paper, the prediction of working stress of quenched and tempered steel and cast steel shaft has been done. The method of simulation of working stress was applied in workpiece of complex form. The working stress was characterized by yield strength and toughness. Proposed method was successfully applied in optimization of the manufacturing of quenched and tempered engineering steel components. Starting point in studying of the mechanical properties of steel castings can be the fact that the mechanical properties of steel castings are derived from the mechanical properties of ordinary steel metal matrix reduced by the influence of the typical as-cast structure, i.e. casting defects on those properties. Hardness and yield strength will be unaffected by most defects. Coarse as-cast microstructure of cast steel lowers ductility and toughness, i.e. impact energy and fracture toughness. Estimation of hardness distribution can be based on time, relevant for structure transformation, i.e., time of cooling from 800 to 500 °C (t8/5). Hardness of quenched and tempered steel can be expressed as function of maximal hardness of actual steel, hardness of steel with 50 % of martensite in microstructure, according to the time and temperature of tempering. The algorithm of estimation of yield strength and toughness was based on hardness, HV.

steel, cast steel, heat treatment, mathematical modelling, mechanical properties

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