Chaikovska G. Improving the stability of structure and properties of hardened bar reinforcement of A500C class when reheating

The paper deals with the processes of structural and phase transformations in the production of rod fittings grade A500C. In order to scientifically based definition of allowable temperature of reheating, which provide stability of structure of steel and high thermo-mechanical properties of reheating rod fittings grade A500C. The paper deals with the applied methods of qualitative and quantitative metallography, electron diffraction translucent and raster microscopy, X-ray analysis, determination of mechanical properties, electrical resistivity and coercive force. The quantitative characteristics of the structure, fine structure and geometric parameters of the lagers are determinated in the thesis, which are formed at different distances from the cooling surface of the thermo-mechanical hardened rods fittings diameters 12 ... 25 mm grade A500C. This allows to control the structure and properties of high-strength rod fittings during its manufacture, and opens the possibility of using it in building structures. The paper shows the quantitative dependency of the mechanical properties and width of surface hardening (martansitno-bainite) layer, which is formed in the rod fittings grade A500C after heat treatment. That allows to predict the mechanical propertieg based on the of rod fittings without a long mechanical tests metallographic researches. Materials of the thesis with the aim of improving the quality of finished products are used for the improvement of production technology for thermo-mechanically rolled hardened light-section mill enterprise PJSC "ArcelorMittal Kryviy Rih".