Heat Treatment of Mining Machinery and Its Components
Mining machinery and its components such as drills, drills bits, teeth, cylinders, buckets and other components often subject to extreme stress and temperatures due to the nature of the mining environment. As such, heat treat processes are essential for maximizing the service life of these components and reinforcing their mechanical properties.
Heat treatment is a process by which the physical characteristics of metal components are altered via the inclusion or exclusion of heat. It is used to improve certain properties of metals used in mining operations such as strength, ductility, hardness and fatigue life. Heat treatment is divided into two processes: quenching and tempering.
Quenching is used to induce martensite structure in the mined metals. It is a hardening process in which the metal parts are heated to a pre-determined temperature then cooled rapidly in oil, water or air. Quenching is most commonly used in mining operations for components made from carbon and alloy steels. The heat treatment reduces the components’ susceptibility to fracture, crack and wear.
Tempering, on the other hand, is used to improve ductility in mined metals. It is a heating process in which the components are heated to a predetermined high temperature followed by a slow cooling process. Tempering helps to increase the components’ hardness, tensile strength and yield strength. It also decreases the components’ brittleness.
Another heat treat process commonly used in the mining industry is thermal cycling. This is a heat treat process used to reduce or eliminate residual stresses in metal components by heat treating them at varying temperatures. Heat treating at lower temperatures increases the grain size while heat treating at higher temperatures decreases the grain size. Smaller grain sizes are preferred in mining components as they increase the components’ ductility and resistance to fatigue and shock.
Heat treat process is a crucial step in the fabrication of mining equipment and its components. Heat treatment of these components ensures proper performance of the equipment and its components under extreme temperature and stress conditions. Heat treatment of mining equipment and components helps to improve the properties of the metal such as strength, ductility, hardness and fatigue life. Quenching and tempering can be used to harden and improve the ductility of the metal, respectively. Thermal cycling can also be used to reduce unleashing stresses and improve the components’ resiliency to shock and fatigue.
