Causes of accelerated failure of excavator bucket teeth crowns when operating in Arctic regions

The mining industry is gradually moving to the Arctic region characterized by permafrost and permafrost soils. Excavation of rocks in these regions is hampered by increased rock strength due to ice freezing of rock pieces after stripping works and requires a new approach to the production of quick-change tools for excavator and loader buckets. The paper analyzes the causes of accelerated failure of excavator bucket crowns after operation in winter in the northern regions of the country; it is shown that the main causes of their accelerated failure are casting defects and insufficient cold resistance of crown material. Hot foundry cracks and large non-metallic inclusions are the initiators of accelerated failure, fatigue cracks and cold brittle cracks develop on their basis during operation. Insufficient cold resistance of steel grades used for these regions and their heat treatment modes have been confirmed, which leads to the development of brittle fracture cracks. It is established that in order to increase the serviceability of excavator crown metal operating in cold climate conditions it is necessary to modify the chemical composition of steel aimed at increasing its cold resistance while maintaining the level of strength and hardness, the main directions of steel composition modification are determined.The study was supported by the Russian Science Foundation grant No. 24-29-00713, https://rscf.ru/project/24-29-00713/.