{ Bulldozer Track Chains }

  • Why do we value the carburizing process for bulldozer track chains?

    The specific impacts of carburizing treatment on the performance of bulldozer track chains are reflected in the following aspects:

    Improved Hardness and Wear Resistance: Carburizing treatment significantly increases the hardness and wear resistance of the chain by increasing the carbon concentration on the surface. For example, in chains used for slagging machines, the enhanced surface hardness allows them to withstand significant tension and pressure, extending their service life.

    Enhanced Fatigue Strength and Crack Resistance: Carburizing treatment forms fine, evenly distributed carbides, avoiding network-like or large clumping of carbides, thus improving fatigue strength and preventing issues such as cracking and flaking. Additionally, rare-earth carburizing processes can create a more gradual gradient in carbon concentration, further enhancing fatigue resistance and wear performance.

    Improved Adhesion and Coating Performance: For components like the transmission shafts of bulldozers, using ion plating and magnetron sputtering composite techniques during carburizing treatment allows for the deposition of NbTaZrC gradient coatings, increasing the adhesion between the coating and the substrate, improving wear resistance, and extending service life.

    Reduced Wear and Increased Longevity: Although carburizing treatment can significantly enhance the hardness and wear resistance of the chain, regular lubrication and maintenance are still necessary in actual use to reduce wear and friction.

    Through the increase in hardness, improvement in fatigue strength, enhancement of adhesion, and reduction of wear, carburizing treatment significantly enhances the overall performance and service life of bulldozer track chains.

  • Key Processes in the Production of Excavator and Bulldozer Track Links

    In the production process of excavator and bulldozer track links, various processes can ensure or enhance the quality of the chains. Here are some key processes:

    Material Selection: The use of high-quality steel is fundamental to ensuring track links. For example, 35MnBN material is used for the link plates of bulldozer track links and is treated through quenching and tempering to improve its core performance.

    Heat Treatment Process: Heat treatment is a critical step for increasing the hardness and wear resistance of the track links. For instance, the link plates undergo medium-frequency quenching to further enhance their wear resistance. Additionally, track links components typically undergo hardening and tempering to ensure proper mechanical properties. 

    Precision Machining Technology: Precision machining technology ensures that the dimensions and fit of each track links component are highly accurate, which improves overall durability and stability. For example, all bushings, pins, and forged link plates are processed with precision to ensure tight and accurate assembly dimensions and sealing performance.

    Lubrication Technology: Lubrication technology is also crucial in the production of track links. Lubricating the chains with oil reduces friction between the bushings and pins, allowing them to maintain superior wear resistance even in harsh working environments. Furthermore, regular lubrication can extend the lifespan of the chains.

    Flaw Detection Process: The flaw detection process for the track links of excavators and bulldozers is an important step in ensuring chain quality. Flaw detection is primarily performed using magnetic particle testing. This non-destructive testing method applies magnetization to the surface of the components, creating a leakage magnetic field in the defect areas, which attracts magnetic particles to form visible magnetic indications that reveal internal or surface defects in the parts, such as cracks or inclusions.

    Magnetic particle testing is a commonly used non-destructive testing method, where magnetization is applied to the surface of the parts followed by the application of magnetic particles. Observing the accumulation of particles at defect sites allows for the identification of cracks or other defects in the parts. This method can detect surface and near-surface defects, ensuring the safety and reliability of the equipment.

     

    The role of magnetic particle testing is to ensure the quality and safety of the track links. Given the enormous loads that track links endure during use, even the smallest crack or defect can lead to severe mechanical failure or accidents. Therefore, magnetic particle testing can promptly detect and address these potential defects, extending the lifespan of the chains and ensuring the normal operation of the equipment as well as the safety of the operators.

  • The Impact of Heat Treatment Processes on Bulldozer Track Chains

    The heat treatment process of bulldozer track chains significantly enhances their performance in the following aspects:

    1. Increased Hardness and Wear Resistance: Heat treatments, such as quenching and tempering, can markedly improve the hardness of chain materials. For example, the composite secondary chemical heat treatment method effectively increases the surface hardness and the thickness of the hard layer on the pin shaft, thereby enhancing the chain's wear resistance and durability.

    2. Improved Mechanical Properties: Heat treatment processes adjust the microstructure of the material, improving its mechanical properties. By optimizing the heat treatment process of 40Cr steel, the treated mechanical properties can meet or exceed those of the original manufacturing material, 42CrMo steel, fulfilling the operational requirements of the chain.

    3. Extended Service Life: Proper heat treatment enhances the fatigue strength and tensile strength of the chain, extending its service life. For instance, applying the quenching-tempering process to drive chain plates and drive chain pins not only increases core hardness and tensile load limits but also significantly saves energy and reduces consumption.

    4. Reduced Maintenance Costs: By improving the wear resistance and fatigue resistance of the chain, the frequency of maintenance and replacements due to wear or damage is reduced, thereby lowering long-term operational costs.

    5. Adaptability to Different Working Environments: Various heat treatment processes can be optimized according to the working environment and load conditions of the chain, ensuring it maintains good performance under different conditions. For example, medium-frequency induction heat treatment technology can be used for large-diameter chains and various sprockets. By improving tooling structures and heat treatment process parameters, more precise heat treatment effects can be achieved.

    In summary, the heat treatment process of bulldozer track chains is a key technology for enhancing their performance. Through appropriate heat treatment, the durability, reliability, and cost-effectiveness of chains can be significantly improved.

     

    Reference link:https://onlinelibrary.wiley.com/doi/10.1002/mawe.201700061