Improving the mode of induction surfacing of reinforcing rings on internal combustion engine valves made of austenitic steel.

Abstract

One of the most common causes of internal combustion engine malfunction is destruction of valves. Valves play a key role in the efficiency, durability and safety of internal combustion engines. The sealing of the combustion chamber depends on the tightness of the working chamfer of the valve to the valve seat. The main part of the heat is removed from the valve precisely through the chamfer and seat, the rest through the valve stem and guide. The valves are divided into inlet and exhaust. The exhaust valves are not cooled by the air entering the cylinder, unlike the inlet valves. Significant temperature and shock loads occur in the combustion chamber due to the disruption of the combustion process. Exhaust valves require increased heat resistance combined with high mechanical properties at extremely high temperatures. For this purpose, a special ring is melted using an induction installation to create a working chamfer. The reasons for the occurrence of characteristic surfacing defects are revealed. These defects detected by the capillary control method represent the dispersion of gas inclusions. A mathematical model of induction surfacing ring installation on the valve has been developed. A formula was obtained for calculating the current at 4 stages, which determines the quality of the surfacing, which takes into account the mass of the surfacing ring and valve, the current strength and heating time at each stage, as well as the ambient temperature. Validation of the mathematical model was carried out, which confirmed the error of the mathematical model at the level of no more than 5 %. Testing in industrial conditions made it possible to reduce the defect of the surfacing of induction surfacing of reinforcing rings on the valves of the internal combustion engine made of austenitic steel.