Increasing the endurance of welded joints operating under low-cycle loading

Fatigue strength and endurance are important criteria when evaluating the efficiency and service life of components and structures. Processes of elastoplastic deformation and contact formation are relatively complicated and the prediction of the operating life of the components under conditions of low-cycle fatigue loading is a scientific problem whose solution is of considerable importance for the national economy. It is also important to examine the problem of increasing the cyclic strength of materials, which determines the reliability margin of many important sections of machines and structures operating under conditions of alternating sign-constant loading. The urgency and complicated nature of the problems increase for compound components, whose application is determined by the need to save expensive high-speed tool steels. In most cases, these compositions are represented by welded joints in steels of the R6M5 type (R6M5K5, R6AM5, R5M5F3, etc.) and medium-carbon steels of the 40Kh type. Welding is carried out in semi-automatic butt welding equipment, followed by machining and heat treatment consisting of stepped quenching from a salt bath into oil followed by triple tempering.