INFLUENCE OF CHEMICAL COMPOSITION AND HEAT TREATMENT ON THE PERFORMANCE PROPERTIES OF HYPEREUTECTOID STEELS OPERATING UNDER CONDITIONS OF INCREASED VARIABLE LOADS AND TEMPERATURES

Abstract

In this work examines the influence of chemical composition and modes of heat treatment of eutectoid steels on the
basic evaluative criteria for the performance of products, which are operated in conditions of increased variable loads and
temperatures. The article analyzes the microstructural features of the steels depending on the carbon content and the impact of
heat treatment (annealing, double and triple normalization) on their mechanical properties, such as the limit of rupture and
flexion, hardness, thermal endurance and durability. The obtained regression equations made it possible to evaluate the effect
of individual chemical elements on thermal endurance and durability at double normalization. On the basis of these equations,
the optimized chemical composition of the eutectoid steel was calculated, which can provide the maximum level of operational
indicators after double normalization. It is concluded that it is advisable to use double normalization with annealing at 600 ° C
to improve the performance properties of eutectoid steels in severe operating conditions , as well as to use optimized chemical
composition to maximize efficiency.