SELECTION OF CAST IRON WELDING METHOD FOR REPAIR AND RESTORATION OF AUTOMOTIVE COMPONENTS

Abstract

The study investigates the features of cast iron welding without preheating, which can be applied in the repair and restoration of automotive components. The relevance of the topic is determined by the inherent difficulties of welding cast iron due to its brittleness, susceptibility to cracking, and the formation of hard structures in the heat-affected zone. An analysis of existing cast iron welding methods was carried out, demonstrating that the use of specialized electrodes and optimized welding parameters can significantly improve the quality of welded joints. Experimental studies were performed on gray cast iron samples obtained from an engine exhaust manifold. Welding was carried out without preheating using three types of electrodes: TsCh-4, MNCh-2, and UTP-8. The quality of the welded joints was evaluated through tensile testing on an MR-100 testing machine, with each sample tested five times followed by the determination of the average fracture load. The obtained results made it possible to objectively assess the mechanical properties of the welded joints. A strength analysis of butt welded joints was conducted, showing that all investigated variants meet the strength requirements and possess a sufficient safety margin. It was established that the TsCh-4 electrode provides a strong but relatively brittle weld, making it suitable for components not subjected to dynamic loads. The MNCh-2 electrode is versatile and ensures a good balance between strength and ductility, while the UTP-8 electrode produces the most ductile and high-quality weld, although it is characterized by a higher cost. The results of the study confirm the effectiveness of welding of cast iron and allow for a well-founded selection of electrode type depending on operating conditions and economic feasibility.