Manganese and carbon partition heat treatment and its microstructure and properties of high boron wear-resistant steel

    
    High boron wear-resistant steel is a kind of wear-resistant material with high boron content, which has significant wear resistance and plasticity. In order to make full use of its properties, appropriate heat treatment is required.
    
    Manganese and carbon partition heat treatment is one of the most effective heat treatment processes for high boron wear-resistant steel. The main purpose of this heat treatment process is to control the partitioning of carbon and manganese inside the steel.
    
    This heat treatment process is generally composed of three steps, including quenching, low temperature tempering and high temperature tempering. In the quenching process, the steel is quenched from 800-850°C to middle-high temperature, so that the austenite inside will transform to martensite, and the fraction carbon and manganese will separate and precipitate, thus forming a fine secondary hardening structure. After the quenching, the steel will undergo low temperature tempering for about 1-4h at about 200°C, followed by high temperature tempering for about 4-5h at about 600-650°C. During this low temperature tempering process, the fraction carbon and manganese can move relatively freely due to the presence of a small amount of austenite, and finally precipitate in different places. During the high temperature tempering process, austenite is present inside the steel, which is beneficial for the carbon and manganese to spread in different areas. Through these three steps, the carbon and manganese can separate and evenly distribute in the steel, and finally form a stable microstructure with high boron alloy.
    
    Manganese and carbon partition heat treatment can significantly increase the wear resistance and plasticity of high boron wear-resistant steel. The specific mechanism of this process can be explained as follows: After heat treatment, the carbides and manganese carbides in the steel can be refined and distributed uniformly, and the grain boundary can become more uniform. Meanwhile, the martensite lath can be refined and tempered, and the toughness of the material can also be increased. The generated microstructure also has a certain amount of boron carbonitride, and its wear resistance is better than that of traditional high boron wear-resistant steel.
    
    ➢Drawing1
    
    As shown in Figure1, the heat-treated microstructure of high boron wear-resistant steel is mainly composed of martensite laths and boron-manganese-based second-phase particles. The above-mentioned microstructure has good toughness, wear resistance and plasticity.
    
    ➢Drawing2
    
    Figure2 shows the stress-strain curve of high boron wear-resistant steel under different heat treatment states. It can be seen from the figure that the ultimate strength and elongation of the steel after the partition of manganese and carbon are significantly higher than before. The good wear resistance, plasticity and fatigue properties of the material can also be proved from the figure.
    
    In conclusion, manganese and carbon partition heat treatment is an effective approach to improve the performance of high boron wear-resistant steel. After the heat treatment, the microstructure and properties of the steel can be significantly improved, so as to make the steel have better wear resistance and plasticity in practical applications.

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