In this work, a multicriteria optimization of the technology for applying discrete coatings by electrospark alloying in the restoration of bronze parts is carried out. As criteria for optimizing the process of electrospark alloying, tribotechnical characteristics were chosen – the wear intensity and friction coefficient of the coating. As adjustable parameters, those design, technological and operational factors that have the greatest influence on the value of optimization criteria are used: coating material; lubricant; operating current; amplitude of electrode oscillations; sliding speed; specific load. As a result of experimental studies, experimental dependences of wear intensity and friction coefficient for various coating materials, sliding speeds and lubrication conditions were obtained. The use of multicriteria optimization of the electrospark alloying technology made it possible to obtain various alternative coating options and technological parameters of their application for various operating conditions. Of the studied coatings, the most effective is a two-layer coating with the first layer SP-2 and an outer layer of the base material bronze BrAZhMts 10-3-1.5, which is explained by the formation of wear-resistant areas based on Mn and Ni. Multiparametric optimization of the electrospark alloying technology made it possible to reveal a combination of structural and technological factors that ensure the formation of discrete coatings with high operational properties in the restoration of bronze parts.

The article discusses the technological process of restoring the geometric dimensional accuracy of piston pins of internal combustion engines (ICE) due to the expansion of the internal hole by a deforming element. As part of conducting research taking into account the resource of the used plasticity of the processed material, the processing modes are determined, the deformation scheme is selected and the geometry of the deforming element is calculated. The selection of the necessary deformation of the part during processing of the piston pin was carried out under the condition of compensating for wear and ensuring an allowance for subsequent mechanical processing. This made it possible to ensure the necessary processing quality of the pin hole surface layer according to the resource parameter of the used plasticity. The deformation scheme was chosen from the condition of ensuring the geometric accuracy of the pin outer surface, which determines the size and uniformity of the allowance for subsequent processing. For these reasons, a scheme was chosen in which the deformation is carried out by two elements with a change of the support end after the first pass. The optimal geometry of the deforming tool was determined from the standpoint of minimizing errors and preserving the initial length of the pin. The results of the conducted experiments showed that using selected expansion schemes, tensions and geometry of the deforming tool, made it possible to ensure the necessary allowance for the next mechanical processing, as well as the invariance of the part length after processing.