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Analysis of the tool work and refusals when heavy machines cutting shows the necessity to use methods of bulk modification for improving structural strength and fracture resistance of cemented carbide cutting plates. It is suggested to test cutting plates to assess the structural strength limit. The accelerated method to estimate the resistance to scattered contact damage and chipping resistance is developed. It is obtained that the pulsed magnetic field treatment (PMNF) of cutting plates (85% WoC, 5% TiC, 10% Co) leads to a dependent on treatment regime increase in structural bending strength limit under static load. The PMTF allows increasing the resistance to scattered contact damage and chipping resistance for cutting plates (92% WoC, 8% Co). It is shown that physical method of pulsed magnetic field treatment is promising for modification of tool materials.

The work is devoted to the problem of fatigue strength of welded-cast joints as applied to the operating conditions of body parts of machines. Such operating conditions are characterized by non-uniformity of intensity and concentration of the load on parts and assemblies during the operation of the equipment. This heterogeneity of the load actualizes production of precisely welded-cast base parts for metalworking equipment beds. This is of considerable technological and economic interest. The aim of the work is to study the strength of welded-cast bearing structures in relation to the work of beds of heavy lathes. Unalloyed medium-carbon structural steel 35L and steel of ordinary quality MCT3 in the form of rolled products were used as the main materials for research. The research methods are presented. The study of the structure and properties of the welded joint made it possible to assess the technical feasibility of using the studied metals in the manufacture of welded-cast bearing structures. It has been established that welding of steel castings with rolled steel causes significant structural and mechanical heterogeneity. The influence of processing technology on the nature of formation of the structure of welded-cast joints is presented. The influence of heat treatment on the value of the hardness of the welded seam and the heat-affected zone was investigated. The study of the fatigue resistance of welded-cast specimens was carried out in relation to the operating conditions of joints undergoing vibration loads at normal temperatures, which can be classified as fatigue with a symmetric load cycle. It was found that the use of heat treatment of welded-cast specimens significantly reduces the mechanical heterogeneity of the joint along the seam and the heat-affected zone. Based on the results of studying mechanical characteristics, the choice of technology for the production of welded-cast joints is justified.