Increasing the durability of soldering wearresistant steel by regulating the redistribution of thermal stresses

Abstract. Problem. The tangential load has a significant influence on the stress state during pressure treatment of metals in the contact zone and on the nature of fatigue failure. As a result of plastic deformations, stresses are redistributed in places of concentration of defects. Since the amount of plastic displacements depends on the level of tangential stresses, the critical number of internal breaks in the material should increase with the increase in the intensity of stresses σ, as the quantity responsible for the formation of the material. Goal. The purpose of the work is to determine the critical values of external loads and the angle of initial propagation of cracks (crack-type defects) at which local or complete destruction of the body will occur. Methodology. Brazing with wear-resistant alloys of the Cr-MnTi-Si and Cr-Mn-Mo-Ti-Si systems was carried out on samples made of 50HNM steel according to the "slide" scheme with flux-cored wire. The effect of temperature on the strength and wear resistance of alloys was studied at elevated temperatures under the conditions of a volumetric stress state using the calculated criterion equations of fracture mechanics. Calculations were made using Mathcad software.Originality. It is theoretically substantiated that at temperatures of 673...873 K and large ratios of crack radii to their depth, mechanical and thermal stresses are responsible for the destruction of the investigated wear-resistant alloys, with an increase in temperature and a decrease in the ratio of the crack radius to its depth, a factor that affects their destruction, there is accumulated plastic deformation. Practical value. Analysis of the results of the influence of temperature stresses on the ultimate external load shows: – at T=673 K, the temperature stresses are 33% of the destructive load;– at T=793 K, the temperature stresses are 44% of the destructive load; – at T=893 K, temperature stresses are 50% of the destructive load