ДОСЛІДЖЕННЯ ВПЛИВУ РЕЖИМІВ ТЕРМІЧНОЇ ОБРОБКИ ДОСЛІДНИХ СТАЛЕЙ ДЛЯ ЗАЛІЗНИЧНИХ РЕЙОК НОВОГО ПОКОЛІННЯ НА МЕХАНІЧНІ ВЛАСТИВОСТІ

Abstract

The safety of railway transport depends on the quality of the metal, the efficiency of the technology for manufacturing rails and wheelsets, and the operating conditions of the railway track. The operational durability of rails is largely determined by the structural state and mechanical properties of the metal of the rail elements. On the basis of a comparative analysis of various methods and modes of treatment of railway rails, it was found that one of the ways to increase the operational reliability of rails can be the optimization of methods for heating and cooling the metal when implementing the modes of their heat treatment. A study of the microstructure of steel laboratory melts up to 10 kg, melted under the conditions of the IHM NASU (the symbol of which is PCT), after furnace heating with cooling the blanks for tensile specimens (55x12x12mm) in various cooling media: in calm air, under a ventilator, blowing with compressor air in water with a temperature of 80˚С. It is found that at cooling rate 5,1˚С / s (cooling air compressor) is obtained a homogeneous structure of fine pearlite with a hardness of the metal at the level of foreign standards. On the basis of technical sources, it has been established that volumetric furnace heating followed by immersion of the test specimens made of steel with 0,84%С, 0,44% Si, 0,95% Mn into an environment providing the metal with a controlled cooling rate of ≈5.1˚C / s contributes to the formation of a lamellar pearlite structure with a hardness of 415 HB. It was found that the use of furnace heating leads to the production of homogeneous austenite in the volume of the samples under study.