Introduction. The article examines the problem of choosing a material and method for increasing the wear resistance of construction machines elements. The performance of construction machines is affected by the reliability of the parts used. The selection of materials for their manufacture allows to calculate the probability of how such elements will affect its ability to work and productivity.Materials and methods. In the process of determining the material and the method for increasing the wear resistance of construction machines, structural steels with various chemical compositions were selected: lowcarbon 08ps (as a model material), 10, 20.30, St3 and low-alloy steels 09G2S and 10HSND, as well as high-carbon steel 65G and boron steel 30MnB5. The methods as high temperature annealing, normalization, injection and high temperature release, thermocyclic processing, cold plastic deformation, thermocyclic processing of steels after cold plastic deformation were used.Results. During the experiment, it was found that both for low-carbon 08ps, 10, 20, 30, St3, and for low-alloy structural steels 09G2S and 10HSND, as well as for high-carbon steel 65G and for boron-containing steel 30MnB5, an increase in the number of TCT cycles (thermal cycling) leads to an increase in the strength properties of the metal. With an increase in the number of cycles over 3-6, the increase in strength properties slows down significantly. Conclusion. In contrast to heat treatment, TCO allows to identify the positive effect of alloying on strength and plastic properties to a greater extent. At the same time, significantly increasing the strength and plasticity, it is possible to obtain previously unattainable values of the work of destruction of alloy steels in the process of various types of loading. Accordingly, the preliminary preparation of steel for the production of individual elements of machines and mechanisms will increase their strength and wear resistance.

Introduction. The experimental studies of the heat treatment effect on the properties of welded joints in working mechanisms of road-building machines are carried out in the work. Studying the structures of the metal itself, as well as welded joints and considering their heterogeneity, the author analyzes the strength characteristics of these objects.Materials and methods. By means of metallographic analysis, as well as using boron-containing steel 30MnB5, which is used for the manufacture of structures for construction machines, as a research material, the author examined its microstructure, which took place in certain zones of welded joints. In particular, welded jointss, fusion zones with an overheating area, a complete recrystallization area and the base metal were studied. We also studied the features of cold plastic deformation of the specified steel sample.Results. It was determined that the mechanical inhomogeneity of the steel at these joints is the cause of the structural inhomogeneity of the welded joints. As a result of this process, some dangerous zones of acting voltages concentration are formed. These conclusions predetermine the need to identify some certain zones that concentrate stresses in themselves, while it is mandatory to strengthen the metal in such zones to standard indicators. An increase in the strength properties of the steel under study is possible by applying cold plastic deformation and subsequent thermal cycling (STC). This is achieved by obtaining a fine-grained metal structure with higher strength. The author defines the welded joints and the zone of its fusion with the base metal and the overheating area as the most dangerous areas subject to loading. To control this process, it is recommended to use the passive fluxgate method in the work, while the fusion zone with the overheating section should be inspected first, and then the weld.Discussion and conclusion. The author comes to the conclusion that the experimental studies carried out can contribute to an increase in the efficiency of the process of reducing the stress concentration (SC) in the elements of construction machines made of steel and subjected to intensive operation by reducing the structural and mechanical inhomogeneity of welded joints.

Representation of the information about the motion surface in the form of discrete maps of passability finds application in the tasks related to the control of autonomous vehicles. The technology was developed, in particular, for use on planetary vehicles. The fields of autonomous transport, transport-technological machines operating in artificial and natural environments, and chassis of mobile robots seem to be promising. The goal is to develop principles for the construction and use of multilayer maps of terrain for mobile chassis. The basic method is to represent the terrain over which the mobile platform moves as a set of cells of a discrete working field. Each cell has a size defined by the size of the chassis in question, the cell is characterized by a set of data represented as a vector. Each component of the vector is part of some surface called a layer. The map contains layers of passability, energy efficiency, etc. The routing can be done by algorithms of a group of methods related to the Lee method. The principles of constructing multilayer passability maps are proposed. A variant of the map based on hexagonal cells is proposed. The principle of constructing an optimal vehicle route which can be based on different optimization criteria has been proposed. Within the framework of the routing problem, a method for constructing a corridor for the safe passage of a vehicle is proposed. The perspectives of application of multilayer maps of passability in control tasks of transport and transport-technological platforms and group control tasks are determined. The basics of technology for preparing terrain information, the principles of using this information in solving the transport task are presented, and examples are given.

In the context of an ever-increasing complication of both the construction of building machines and mechanisms and the conditions of their operation, the issues of achieving reliability and durability of the main welded joints are actualized, since the quality of the welded joint determines the operability of the assembly and the machine as a whole. In this regard, ensuring satisfactory weldability and obtaining a better welded joint are necessary conditions of increased strength for welded structures on which the working bodies of construction machinery, as well as mechanisms and their assembly units are mounted. The article addresses the key issues of improving the reliability of welded structures of building machines. Special attention is paid to the problems of strengthening hazardous areas, as well as the restoration of such zones in the welded structures of construction machinery. As an example, the article considers the frame of a forklift truck equipped with a hydraulic manipulator. Particular emphasis is placed on the fact that when calculating the distances between welds, it is necessary to take into account its dependence on the welding conditions and the parameters of the frame structures of construction machines. The stress-strain state of the frame was evaluated by modeling the state of the structure in various situations. Using finite element analysis programs, it was found that it is possible to reduce local stresses that exceed the tensile strength of the material and cause the risk of microcracks due to the welding of overlays with short seams in a checkerboard pattern, as well as finding the optimal parameters of the welds taking into account the stress concentration. It was also established during the study that the greatest influence on the value by stress concentration factors is exerted by the radius of the transition from the base metal to the weld metal. An increase in the transition radius from 0.1 mm to 1.0 mm makes it possible to reduce the value of the stress concentration coefficient.