Next-generation tungsten carbide cutting bits through cryogenic treatment technique for superior rock cutting performance for mining applications: An experimental study

Abstract

The mining sector seeks innovation to enhance operational efficiency and prolong cutting tool life. This research investigates the impact of cryogenic treatment (CT) for 12, 24, and 36 h on tungsten carbide cutting bits used in mine machineries, focusing on its effects on cutting force, energy consumption, and tool wear during lab-scale linear rock cutting. Microstructural analysis and hardness testing follow CT, revealing improvements in hardness, the formation of new compounds, and the presence of eta carbides. Analysis of linear rock cutting experiments shows that longer holding periods under CT lead to reduced cutting force, energy consumption, and tool wear. Comparing CT 24 to untreated bit at a cutting speed of 200 m/s, CT 24 demonstrates reduction in specific energy by 39.35 %, 41.13 %, and 29.39 % at depth of cut (DoC) of 2 mm, 4 mm, and 6 mm, respectively. Additionally, CT 24 exhibits significantly lower wear rates (79.24 %, 85.44 %, and 85.01 %) compared to UT bits at the same cutting speed. Microstructural analysis identifies multiple wear mechanisms in both treated and untreated worn tools. To optimize the cutting process for mining efficiency, grey relational analysis and Python-based non-dominant sorting are employed. Grey relational analysis identifies 24-h CT, a cutting speed of 200 m/s, and a 2 mm depth of cut as optimal. Non-dominant sorting suggests 24-h CT, a cutting speed of 200 m/s, and 2–4 mm cut depth for optimal results. Pareto solutions indicate specific energy ranging from 14.96 to 9.20 kWh/m³ and wear rates ranging from 0.33 to 0.39 × 10⁻⁴ cm³/cm. Insights from this study offer valuable guidance for the mining industry to enhance cutting tool efficiency and promote environmentally sustainable mining practices.