RESTORATION OF THE LOWER HEAD OF "CHIPPED" CONNECTING RODS

Abstract

Modern high-precision machines for machining basic engine parts allow for high-quality restoration of a wide range of various machine parts and mechanisms. The article considers the restoration of the connecting rod, one of the basic and most numerous parts of the connecting rod – piston group. (Research purpose) The research purpose is in analyzing the possibilities of various technologies for the restoration of "chipped" connecting rods and giving technological proposals for their restoration for the company "Motortechnology". (Materials and methods) The research object is the "chipped" connecting rod of the Cummins engine as one of the most massive engines used on KAMAZ vehicles. It was proposed to use electric spark processing technology to restore the lower head of the "chipped" connecting rod. It is possible to obtain a new layer with predictable characteristics depending on the parameters of the spark discharge, the composition of the electrode material, the material of the work piece and other factors. The resulting coating will have properties different from the base material, which can be controlled within a wide range and provide the required qualities, such as increased microhardness, wear resistance, heat resistance. The important advantage of the electric spark processing technology is the absence of a significant thermal effect on the part during processing, therefore, thermal residual deformation of the part is excluded. (Results and discussion) The article presents the data on the effectiveness of the restoration of "chipped" connecting rods with the use of electric spark technology as an independent technological process, and when using various combined coatings. (Conclusions) To improve the physical and mechanical properties of the coating when restoring "chipped" connecting rods with a wear of more than 100 micrometers, it is advisable to restore them in a combined way, where the first layer is an electric spark coating, the second layer can be gas dynamics, metal polymers or an electrochemical coating method.