Дослідження відновлення корпусних деталей автомобільних двигунів методом електродугової металізації

Abstract

Road transport ensures a rational organization of production and transportation of products. The cylinder block is a basic part, mechanisms and engine parts are attached to it. Engine blocks are operated with high loads. Defects arise and develop, which can be eliminated during major repairs. Improving the methods of restoring worn cylinder blocks of automobile engines is an urgent task. The possibility of restoring parts with such defects by gas-thermal methods was considered. The total level of defects that can be eliminated by applying a restorative coating by the method of electric arc metallization is 37%. The analysis of literary sources shows that surfacing and welding methods do not ensure the quality of the restored part. Gas-thermal methods are often used in the process of repairing parts. The most technological and effective is electric arc metallization. Productivity of electric arc metallization can be very high. Operating costs of using electrometallization are small. The equipment is relatively simple. Restoration of parts by electric arc metallization increases wear resistance and durability of the engine. To assess the repeatability of block defects, we analyzed a sample of 20 truck cylinder blocks from different manufacturers. It was established that the resource of the block depends on: wear of the main bearing beds, holes, cracks, damage to the thread and breakage of pins and holes. Laboratory experiments on the application of electroplating coating were carried out on samples of high-strength cast iron. Preparatory processing of samples - shot blasting. Experiments on sputtering of samples were carried out with known powder wires PG-SR4 and PG-SR4+3% Al with a diameter of 2.0 mm. Spraying was carried out with an EM-17 electric arc metallizer. Tests on the adhesion strength of the coating to the base metal were carried out using the adhesive method. From the research results, we can see that the coating applied with PG-SR4+3%A1 wire is destroyed at the joint under a higher load than the corrosion formed by PG-SR4 wire. At the same time, the adhesion strength also exceeds, and is 22.9 MPa. The microhardness of the coating built up with powder wire PG-SR4+3%A1 exceeds the level of microhardness of the surface built up with wire PG-SR4. Microhardness in both cases. decreases with distance from the surface of the deposited layer. Conclusions. From the conducted research, it follows that the electric arc restoration does not have a thermal effect on the part, provides high adhesion strength of the applied layer, which prevails over the majority of traditional methods of restoration of parts. In addition, the method of electric arc metallization is characterized by low energy consumption, small-sized and mobile technological equipment. Therefore, there is a need to continue the research of electric arc metallization in the restoration of worn surfaces of car parts.