Evolution of the Structure and Mechanical Prop-erties of Welded Joints of Medium-Carbon Steels, Made by Rotational Friction Welding, with Heat-ing

The paper presents the results of investigations of welded joints made of 32G2 and 30HGSA steels made by rotational friction welding on a Thompson 60 welding machine. The structure is analyzed in the initial state and after various temperature modes of heating. The results of the hardness measurement in various zones of the welded joint are given, the results of the tensile and toughness tests are presented. The features of phase transformations occurring in welded materials during welding and subsequent heating at different temperatures, which affect the degree of mechanical inhomogeneity and the level of mechanical properties are shown. It is shown that the integral mechanical properties of a welded joint of 32G2-30HGSA steels during a tensile test are determined by the properties of the zone of thermomechanical influence or induction heating of 32G2 steel, as the least durable area in which deformation is localized and subsequent destruction. On the basis of the studies carried out, the optimal temperature annealing regime is recommended from the position of equal strength and reliability of the structure.