STUDY OF THE INFLUENCE OF PLASTIC DEFORMATION ON THE PROPERTIES AND STRUCTURE OF STEEL AFTER HEAT TREATMENT

Abstract

The work investigates the influence of plastic deformation at subcritical temperatures, for example, hot rolling, cold deformation rolling, drawing on the structure, as well as the properties of steels after heat treatment – this is annealing, normalizing, and quenching. It is shown that cold deformation by rolling, cold drawing will accelerate the process of spheroidization of cementite during the process of spheroidizing annealing, respectively. At the same time, the nature and degree of influence of rolling at subcritical temperatures, deformation on the structure and properties of heat treatment of an alloy, for example, steel, will be similar in one way or another. It is found that regardless of the selected method of deformation in the ferritic-cement zone, a rational choice of its parameters can occur when using grinding of the final structure and possibly substructural strengthening to increase the mechanical properties of structural steels. For example, deformation even at low temperatures will certainly contribute to the acceleration of the processes of spheroidization and ultimate yield strength, as well as the hardness of steel after heat treatment with phase recrystallization at short exposure times and heating temperatures. It has also been established that increasing the degree of cold deformation will certainly affect the strengthening of steel after heat treatment. It has been shown that the positive effect of preliminary deformation on the properties of structural steels both after annealing and thermal improvement is due to the grinding of the initial austenitic grain and, accordingly, the final structure of the steel, as well as the substructural strengthening of ferrite in connection with the effect of inheritance of defects in the crystal structure, respectively, during polymorphic transformations. We believe that during rolling at subcritical temperatures, a developed and stable substructure will already form in ferrite, which is inherited by the formed austenite much better than disordered defects of the crystal structure.