engleski

Influence of two different heat treatment procedures on mechanical and fracture properties of 65Si7 steel

This paper deals with the results of investigations of two different heat treatment procedures and their influence on some mechanical properties as well as on the magnitude of some fracture mechanics parameters for a particular type of steel. Experimental investigations were performed on the specimens made of 65 Si 7 steel. The processes occurring by tempering of two different microstructures of the steel, i. e. martensite and lower bainite were investigated. An advantage of austempering over hardening and tempering is in obtaining the bainite microstructure. Steel of bainite microstructure has a greater toughness, ductility, contraction, fatigue strength and a better fracture toughness than a tempered martensite of the same type of steel. A bainite microstructure also gives a better resistance to thermal fatigue in comparison with martensite microstructure. The above mentioned improved values of mechanical properties refer to the untempered state of bainite.

Heat treatment; Steel 65Si7; Mechanical properties; Fracture mechanics parameters

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