Effect of heat treatment on microstructure and mechanical properties of low-alloy wear-resistant steel NM450

    
    Introduction
    
    NM450 is a low-alloy wear-resistant steel, which is often used in the production of wear-resistant parts such as large container liners, bulldozers, and top plates of automobiles. It is resistant to abrasion and possesses high strength, hardness and toughness. Due to these properties, it can resist a large amount of wear and tear without breaking down. In order to further improve the mechanical properties of NM450, heat treatment is often used. Heat treatment can cause microstructural and phase transformations in the material, as well as changes in its mechanical properties. This article provides an overview of the effects of heat treatment on the microstructure and mechanical properties of NM450.
    
    Microstructure
    
    Heat treatment in NM450 is typically used to improve the hardness, toughness and dimensional stability of the material. When subjected to heat treatment, the microstructure of the steel changes depending on the temperature and time of heat treatment. Heat treatment temperatures for NM450 range from 200°C to 800°C.
    
    At temperatures below 400°C, the microstructure of NM450 is that of ferrite, which is relatively soft and ductile. It is also relatively stable and resistant to wear and tear. Above 400°C, the microstructure of NM450 changes to bainite, which is harder, tougher and more resistant to wear and tear than ferrite. Above 600°C, the microstructure of NM450 changes to martensite, which is the hardest and toughest of the three microstructures.
    
    Mechanical Properties
    
    The mechanical properties of NM450 can be improved by heat treatment. Heat treatment affects the strength and hardness of the steel. At temperatures below 400°C, the strength and hardness of the steel increase with increasing temperature. At temperatures above 400°C, the strength and hardness of the steel decrease with increasing temperature.
    
    The hardness of NM450 can be enhanced by tempering the steel. Tempering is a process of heating the steel at a specific temperature for a specific time. Tempering increases the hardness of the steel and makes it more wear-resistant.
    
    Conclusion
    
    Heat treatment has a significant effect on the microstructure and mechanical properties of NM450. At lower temperatures, the microstructure is ferrite, resulting in a relatively soft and ductile material. At higher temperatures, the microstructure changes to bainite or martensite, resulting in a harder and tougher material. Heat treatment also improves the strength and hardness of the steel, making it more wear-resistant. Tempering is an effective way to further increase the hardness of NM450.

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