Materials and Technologies for Restoration of Worn Surfaces of Automobile Parts
Authors:   Poltava State Agrarian University, Ivankova Olena , Burlaka Alexei ,   Poltava State Agrarian University, Bartosh Vitaly ,   Auto-Motor Company LLC
Published: February 2025

The materials from which car parts are made determine: the level of manufacturability in the manufacturing process; reliability and durability during operation; economy and maintainability of the car. The purpose of the article. To study the level of defects of crankshafts of automobile engines, to analyze methods of restoration and to choose the optimal one. To conduct experiments on the use of electric spark build-up, to determine the optimal materials for build-up, as well as the parameters of the technological process.
The regularities of the formation of defects in the crankshafts of truck engines have been analyzed. A sample of 20 engines was studied. It has been determined which defects have the greatest effect on the service life of crankshafts. Recovery methods were analyzed and the optimal one was selected. Conducted research on the use of electrospark build-up, experiments on layer build-up on steel samples. The following were investigated: the dependence of the total growth of the cathode on the carbon content and the number of electrode passes, the thickness of the layer applied to the surface of the part, the hardness of the coated samples, and the adhesion strength of the built-up layer to the main one were determined. We determined the optimal materials for building up, as well as the parameters of the technological process. A high (638.7 MPa) level of strength was established by tests on the adhesion strength of the built-up layer to the base. On the basis of the conducted tests, it was established that the steel samples with the applied coating have a higher hardness compared to the sample after heat treatment. Experiments have shown that electrode materials with a carbon content of 1.0-2.5% and chromium content of 10.0-25.0% are optimal for electrospark build-up of 45G, 40X steel samples.
Conclusions. Most of the crankshafts that were overhauled had worn connecting rods (95%) and main journals (93.8%). Elimination of these defects is possible by applying a coating using the electrospark build-up method. Experiments on the dependence of the total growth of the cathode and the thickness of the coating on the chemical composition of the anode and the number of electrode passes when coating samples made of 45G and 40X steels showed that the growth of the cathode increases with increasing pulse energy. It was established that when using electrodes with a carbon content of 1.5-2.5% and chromium content of 10.0-25.0%, it is not advisable to make more than 3 passes of the electrode, since 3 passes provide sufficient growth of the cathode and coating thickness. It was established that the steel samples with the applied coating have a higher hardness compared to the sample after heat treatment and a high (638.7 MPa) level of adhesion strength of the built-up layer to the base. The possibility of using this method at technical service enterprises to increase the durability and reliability of parts has been confirmed. Therefore, research on the development of the technology for the restoration of specific parts of the equipment by the method of electrospark build-up is still an actual task and requires continued research.