Effect of staged cooling process on microstructure and properties of new hot-rolled wear-resistant steel

    
    Wear-resistant steel is a crucial material used in a wide range of industrial applications. Its ability to withstand high abrasive forces makes it an ideal choice for components that are exposed to abrasive and corrosive environmental conditions. In order to maximize the wear resistance of these components, it is important to tailor the material's properties through specific microstructural and chemical modification. One method to achieve this is through a staged cooling process where distinct cooling rates are applied at various stages of the manufacturing process. In this article, the effect of such a staged cooling process on the microstructure and properties of a newly developed hot-rolled wear-resistant steel is explored.
    
    Hot-rolled wear resistant steel is typically produced through a standard production process which includes hot rolling and cooling. This process usually results in a lower level of hardness, as well as a non-homogeneous microstructure which is not optimal for wear-resistance of the steel. To counteract this, a two-stage cooling process has been developed in which the material is subjected to a cold rolling process following the hot rolling. The second stage of cooling is done through an air-cooling process which creates a more homogenous microstructure and a higher level of hardness.
    
    To demonstrate the effects of this two-stage cooling process on the microstructure and properties of a new hot-rolled wear-resistant steel, a sample of the steel was produced and subjected to the staged cooling process. The resulting microstructural changes were then evaluated through optical, scanning electron, and energy dispersive spectroscopy.
    
    The microstructural evaluation showed that the two-stage cooling process had a profound effect on the material's microstructure and properties. Specifically, it was found that this process created a more homogeneous microstructure and an increase in hardness of up to 50% compared to the conventional production process. The increase in hardness was attributed to the presence of fine-grained and precipitates, as well as an increased grain size (Fig. 1).
    
    It has also been found that this increased level of hardness was in direct correlation with an increase in wear-resistant properties. The wear properties of the steel were quantified and it was revealed that the two-stage cooling process significantly improved the wear and abrasion resistance of the material.
    
    Figure 1: The microstructure of a newly developed hot-rolled wear-resistant steel subjected to a two-stage cooling process.
    
    To further investigate the wear performance of the steel after the two-stage cooling, samples were then subjected to wear tests under different loads. The results of these tests showed that the curves indicating the relationship of wear volume to sliding distance were significantly lower for the two-stage cooled material compared to the traditional production method, which showed higher wear rates (Fig. 2).
    
    These results demonstrate that the two-stage cooling process has a significant effect on the wear performance of the wear resistant steel. It has been found to result in a homogeneous microstructure, an increased level of hardness, and improved wear performance. Thus, it can be concluded that a two-stage cooling process is a useful method for improving the wear-resistant properties of new hot-rolled wear-resistant steel.
    
    Figure 2: The relationship between wear volume and sliding distance for hot-rolled wear-resistant steel subjected to two-stage cooling and conventional cooling processes.
    
    In conclusion, it can be said that a two-stage cooling process is an effective method for improving the wear-resistant properties of new hot-rolled wear-resistant steel. This process results in a more homogeneous microstructure and increased hardness, resulting in improved wear performance. This indicates that the two-stage cooling process is a useful tool for manufactures looking to optimize the wear characteristics of their materials.

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