Research on microstructure and properties of wear-resistant steel under different tempering processes

    
    Wear-resistant steel is an important material for many industries, such as automobiles and aeronautics. Its research and development has always been the focus of research. Under different tempering processes,Due to its unique metallurgical effects, it can improve the surface, comprehensive mechanical properties, heat treatment and so on, which can meet the requirements of high-end applications.
    
    The tempering process of wear-resistant steel is a heat treatment process, which is mainly aimed at alleviating the stress state of martensite structure and improving the performance of wear resistance. The process requires the determination of appropriate tempering temperature, cooling rate and holding time, so that it can obtain high wear-resisting steel performance.
    
    1. Microstructure Analysis of Wear-Resistant Steel
    
    The microstructure of wear-resistant steel after tempering can generally be divided into three parts: bainite, ferrite and a small amount of retained austenite. After the tempering of wear-resisting steel, The microstructure mainly contains tempered bainite, and a small amount of ferrite, pearlite and retained austenite. Under different tempering processes and tempering temperatures, different refined microstructure is formed.
    
    At room temperature, the microstructure of wear-resistant steel after tempering is compact. As the tempering temperature and time increase, the microstructure becomes more refined, and carbide and TiC-rich particles are evenly distributed in the matrix. The average size of carbide particles is between 0.1—1 μm. Figure 1 shows the microstructure of the wear-resistant steel tempering at different temperatures.
    
    
    FIGURE 1: Microstructure of wear-resistant steel tempering at different temperatures (Source: National Center for Nanomaterials)
    
    2. The Wear Resistance of Wear-Resistant Steel
    
    The wear resistance of wear-resistant steel after tempering treatment is an important issue. The wear resistance is mainly related to the hardness and microstructure of the steel. The hardness of the steel after tempering increases with the tempering temperature. When the tempering temperature is above 350 °C, the hardness is detected, and the wear resistance is increased in a large span.
    
    On the other hand, the microstructure of the wear-resistant steel is also the key factor that affects its wear resistance. The fine microstructure formed by tempering treatment can improve the comprehensive strengthening of wear-resistant steel, which in turn increases its abrasion resistance.
    
    When wear resistant steel is tempered at a constant temperature, its wear resistance will increase at the beginning and reach a peak, then gradually decrease as the time increases. Such as the wear resistance of wear-resistant steel after tempering at 550°C. Figure 2: Wear resistance of wear-resistant steel after tempering at 550°C
    
    Fig.2 Wear resistance of wear-resistant steel after tempering at 550°C (Source: National Center for Nanomaterials)
    
    3. Conclusion
    
    In conclusion, A tempering process is an important part of the process for improving the comprehensive performance of wear-resistant steel, and the tempering temperature, tempering holding time and cooling rate of the wear-resistant steel are all factors to be considered in the tempering process. According to the microstructure and wear resistance of wear-resistant steel after tempering, it can be found that when the tempering temperature is higher than 350°C, the wear resistance can be improved in a large span, and the optimal tempering temperature should be determined according to the actual application performance.

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