In the complex mechanical structure of gearbox, the durability and strength of gear parts are directly related to the performance and service life of the entire gearbox. The selection and treatment of special materials are the key to achieving this goal.
In terms of material selection, alloy steel is one of the commonly used high-quality materials. For example, chromium-molybdenum alloy steel contains alloy elements such as chromium and molybdenum. Chromium can significantly improve the oxidation resistance and corrosion resistance of steel, making it difficult for gears to rust and corrode in complex working environments, thereby maintaining their structural integrity. Molybdenum can effectively improve the strength and toughness of steel, especially in high temperature environments. Molybdenum can inhibit grain growth, so that gears can still maintain good mechanical properties when subjected to the heat generated by high-load operation, and are not prone to deformation or fracture.
Carburized steel is also an ideal material for gearbox gear manufacturing. It has the characteristics of low carbon content. After carburizing treatment, the surface carbon content increases significantly, forming a high-carbon hardened layer. This hardened layer has extremely high hardness and can effectively resist the wear of the tooth surface during meshing, significantly improve the wear resistance of the gear and extend its service life. The core still maintains the toughness of low-carbon steel, so that when the gear is subjected to impact load, it can rely on the toughness of the core to absorb energy and avoid sudden fracture, achieving a good combination of strength and toughness.
For material processing, heat treatment technology plays a vital role. Normalizing can refine the grains, uniform the structure, and eliminate the internal stress generated by the gear blank during the forging process, laying the foundation for subsequent processing and final performance improvement. Quenching and tempering processes are the core links to improve the strength and toughness of gears. During quenching, the gear is quickly cooled to transform austenite into martensite, thereby greatly improving the hardness and strength of the gear. However, the brittleness of the gear after quenching is relatively large. Tempering treatment reduces internal stress through appropriate heating, adjusts the balance between hardness and toughness, and makes the gear have sufficient strength to transmit power and a certain toughness to cope with impact and vibration.
In addition, surface strengthening treatments such as shot peening are also widely used. By high-speed jetting projectiles hitting the gear surface, the surface is plastically deformed and residual compressive stress is formed. This residual compressive stress can effectively offset part of the tensile stress borne by the gear during operation, inhibit the generation and expansion of cracks, further improve the fatigue strength and wear resistance of the gear, ensure that the gearbox gear can still operate stably and reliably under long-term and high-intensity working conditions, and provide solid guarantee for the efficient operation of vehicles and other equipment.
