Comparative Study on Microstructure and Properties of Low Alloy Bainite Wear-resistant Steel

    
    Abstract
    
    This paper compares the microstructure and performance of low-alloy bainite wear-resistant steel and reviews the development of wear-resistant steel. Low-alloy bainite wear-resistant steel is an important material for the manufacture of many important components due to its excellent wear resistance, good toughness, and low cost. In this article, a comprehensive comparison of the physical and chemical properties, microstructure, as well as the performance of the steel under different heat treatment conditions is carried out. The optimized heat treatment process of the steel is also analyzed. The results show that the made low alloy bainite wear-resistant steel has a good physical and chemical property structure, a stable bainite structure, and a good wear-resistant performance.
    
    1. Introduction
    
    Low-alloy bainite wear-resistant steel is an important kind of wear-resistant materials, which is widely used in engineering machinery and other equipment, especially for some severe wear parts. It has excellent wear resistance, good toughness and stability, and low cost. The high strength, wear resistance and other fine properties are much better than those of common cast iron and low-alloy steel. Therefore, low-alloy bainite wear-resistant steel has become the main material for the manufacture of many important components, such as wheel hub, shaft sleeve, axle, slide block, etc., and its application fields are constantly widening.
    
    2. Comparison of Structure
    
    2.1 Chemical Component
    
    The chemical components of low-alloy bainite wear-resistant steel contain C, Si, Mn, Cr, Mo, V, Nb, Ti, P and S. The specific elements are slightly different according to different requirements, but the main chemical components are determined by the appropriate balance of carbon content and alloying elements. The carbon content of the steel is usually between 0.5% and 0.8%, and an appropriate amount of alloying element is added according to the actual need. Generally, the number of alloying elements is within 8.
    
    2.2 Microstructure
    
    Low-alloy bainite wear-resistant steel has a two phase microstructure. The main phase is a tempered bainite form, and the secondary phase is carbides. Its main phase is made up of fine bainite laden with carbides, and there are martensite structures, small amounts of retained austenite and some amounts of ferrite under the state of not heat-treated.
    
    3. Comparison of Performance
    
    3.1 Physical and Mechanical Properties
    
    The low-alloy bainite wear-resistant steel has a good physical and mechanical property structure. The tensile strength is above 900MPa, the yield strength is above 800MPa, and the elongation is above 10%. The fatigue strength is significantly enhanced by well-controlled carbon elements and suitable heat treatment process.
    
    3.2 Wear Resistant Performance
    
    The wear resistant performance of low-alloy bainite wear-resistant steel is good, its wear resistance is higher than that of low alloy steel and due to the uniform distribution of carbides, the wear rate of parts is greatly reduced.
    
    4. Heat Treatment Process
    
    The heat treatment process of low-alloy bainite wear-resistant steel is of great importance, which is closely related to the performance of the steel. Generally, a two-stage continuous process is adopted. The first stage is a tempering process at a temperature of 400°C-600°C for a certain period of time, and the second stage is a quenching process, which is conducted at a high temperature of 960°C and then cooled at a rate of 10℃/s~20℃/s until room temperature, so as to obtain a desired bainite structure.
    
    5. Conclusions
    
    The low-alloy bainite wear-resistant steel has a comprehensive physical and chemical properties, good wear-resistant performance and long service life due to its uniform bainite structure and fine carbide particles. An appropriate heat treatment process is necessary to obtain a desired bainite structure and enhance the physical and mechanical properties of the steel. Therefore, the correct selection of heat treatment process and the corresponding parameters of parameters have an important influence on the performance of low-alloy bainite wear-resistant steel.

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