The manufacturing industry is developing faster and faster, and the performance requirements for mechanical parts are becoming more and more stringent. Sometimes a single heat treatment process can no longer meet its performance requirements, and a combination of multiple heat treatment processes is required. In order to save energy, reduce consumption, and pursue better performance, various types of composite (combination) processes such as toughening treatment, surface alloying, surface heat treatment, surface functional plating, and deformation strengthening have begun to be used, which greatly improves the performance of mechanical parts and opens up a new field of heat treatment technology - composite heat treatment technology.

In fact, composite heat treatment is the combination of two or more heat treatment processes, or the combination of heat treatment and other processing technologies, so that different processes complement each other and enhance each other, more effectively improving the performance of the workpiece, tap the potential of materials to a greater extent, and enable parts to obtain excellent performance that cannot be achieved by a single process, and try to save energy, reduce costs and improve production efficiency.

Principles that should be followed in heat treatment process compounding: ① Function inheritance. When considering the possibility of combining the two processes in composite heat treatment, attention should be paid to the reasonable coordination of heating and cooling specifications, as well as the interaction between them and their impact on the structure and properties of steel. The effect obtained by the former heat treatment should be inherited during the heat treatment of the latter, and the effect of the previous process should not be completely eliminated in order to obtain another performance. The two should complement each other rather than neglect one at the expense of the other. ②High quality and economical. It should be based on technical feasibility and economic rationality. Generally speaking, the performance and service life of the workpiece should be greatly improved through composite heat treatment, but the distortion and cracking tendency of the workpiece and the cost of heat treatment should not be significantly increased, and the cost of heat treatment should be as much as possible. The composite heat treatment process is simplified and the heat treatment cycle is shortened.

Tractor Parts Application

Composite heat treatment is an advanced technique used to enhance the durability, wear resistance, and performance of metal surfaces, particularly in high-stress tractor parts. This method combines different heat treatment processes to achieve optimized surface properties, such as improved hardness, corrosion resistance, and fatigue strength. Tractor parts such as gears, shafts, and drive components are critical to the machinery's operation and longevity, and composite heat treatment plays a crucial role in ensuring these parts can withstand harsh agricultural environments.

This article explores which tractor accessories benefit from composite heat treatment, how it improves their function, and the overall importance of this treatment in enhancing tractor performance.

Key Accessories Benefiting from Composite Heat Treatment

Several essential tractor parts and accessories, primarily those subjected to heavy loads, friction, and environmental stress, benefit significantly from composite heat treatment. These parts include:

Gears:

Gears in a tractor’s transmission system are subject to constant friction, heavy loads, and rotational stress. Composite heat treatment improves their wear resistance and hardness, allowing them to maintain smooth operation under extreme conditions. Treated gears have higher fatigue strength, which reduces the risk of failure from repeated loading and unloading cycles.

Drive Shafts:

Driveshafts transfer power from the tractor’s engine to the wheels or other moving parts. These shafts endure significant torque and stress, making them prone to wear and fatigue over time. Composite heat treatment strengthens the surface of the drive shafts, enhancing their ability to resist wear, cracking, and deformation.

Camshafts:

Camshafts control the opening and closing of engine valves, and their surfaces must be highly resistant to wear due to constant contact with cam followers. Composite heat treatment ensures that the camshaft surface remains smooth and durable, preventing premature wear and maintaining engine efficiency.

Pistons and Piston Rings:

Pistons and piston rings in tractor engines are exposed to high temperatures and friction during engine operation. Composite heat treatment enhances their thermal stability and wear resistance, improving engine efficiency and extending the service life of these critical components.

Hydraulic Cylinder Components:

Hydraulic systems rely on smooth operation and precise control of fluid pressure. Hydraulic cylinder rods, pistons, and seals undergo composite heat treatment to improve their resistance to corrosion and wear, ensuring reliable performance and reducing the risk of leaks or malfunctions.

Improvement of Functions Through Composite Heat Treatment

Composite heat treatment enhances the functionality of metal tractor parts in several key ways:

Increased Surface Hardness:

One of the primary goals of composite heat treatment is to increase the surface hardness of metal parts without affecting the core’s toughness. Processes like carburizing or nitriding are often combined with heat treatments to introduce carbon or nitrogen into the metal’s surface, creating a hard, wear-resistant outer layer. This increased hardness helps the treated parts resist abrasion, friction, and impact, leading to longer service life and better performance under heavy loads.

Improved Wear Resistance:

Tractor parts like gears and drive shafts experience high friction during operation, leading to gradual wear. Composite heat treatment enhances the wear resistance of these parts, reducing the rate at which they degrade over time. The combination of surface hardening and tempering processes ensures that parts can handle prolonged exposure to friction without significant loss of performance.

Enhanced Corrosion Resistance:

Many tractor parts operate in harsh outdoor environments where they are exposed to moisture, chemicals, and dirt. Composite heat treatment processes, such as nitrocarburizing or plasma nitriding, improve the corrosion resistance of metal surfaces, protecting them from rust and oxidation. This is particularly beneficial for parts like hydraulic components, which must remain corrosion-free to prevent fluid leaks or system failures.

Increased Fatigue Strength:

Fatigue is a common cause of failure in metal parts subjected to cyclic stresses, such as drive shafts, camshafts, and gear teeth. Composite heat treatment enhances the fatigue strength of these parts by refining the metal’s microstructure and creating a tougher surface layer. As a result, parts can endure repeated loading and unloading without developing cracks or deformities.

Improved Thermal Stability:

High-temperature components like pistons and camshafts can benefit from composite heat treatments that improve their thermal stability. These treatments help parts resist thermal expansion, warping, and cracking under elevated temperatures, which is essential for maintaining engine performance and reducing downtime due to part failure.

Conclusion

Composite heat treatment of metal surfaces is a vital process in the production and maintenance of tractor parts, particularly for components subjected to heavy loads, friction, and extreme environmental conditions. Accessories such as gears, drive shafts, camshafts, pistons, and hydraulic cylinder components benefit significantly from this treatment, which enhances their surface hardness, wear resistance, corrosion resistance, and fatigue strength.

By improving the performance and longevity of these parts, composite heat treatment contributes to the overall reliability and efficiency of tractors, helping operators maintain productivity while reducing maintenance costs. As technology advances, further refinements in composite heat treatment techniques will continue to drive improvements in tractor part performance, ensuring that these machines remain durable and effective for years to come.