Delamination Defect Analysis of Medium Manganese Wear-Resistant Steel Continuous Casting Slab

    
    Medium manganese wear-resistant steel is a kind of medium-manganese wear-resistant steel that is widely used in wear-resistant steel casting and rolling industry. The continuous casting slab of medium manganese wear-resistant steel is mainly used in manufacturing of steel components with extremely high wear resistance like screw conveyor, etc.
    
    Continuous casting slab is one of the most important steps in steel production; consequently, any defects present in this form of steel can have serious detrimental effects for its end application. One of the more common defects that occur in the continuous casting slab of medium manganese wear-resistant steel is delamination.
    
    Delamination occurs when there is an imbalance of internal and external forces in the steel. This imbalance can cause the material to experience internal stress, causing it to come apart and separate from itself. The internal stress can be caused by factors such as grain boundary misorientation, unequal strain hardening, and mechanical and thermal stresses.
    
    The most common form of delamination occurs when the internal and external stresses cause the steel slab to break up into very thin layers. This process is typically referred to as cracking or crazing. This can severely affect the properties of the steel, rendering it unsuitable for use in high wear-resistance applications.
    
    The other type of delamination that is seen in the continuous casting of medium manganese wear-resistant steel is called ‘haloing’. In this phenomenon, the interior of the slab appears to be recessed and surrounded by an outer rim that is called a ‘halo’. This halo is caused by the unequal strain hardening and high mechanical stresses.
    
    In order to detect and diagnose delamination in the continuous casting slab of medium manganese wear-resistant steel, several methods are used. Visual inspection is one of the simplest and most commonly used methods, whereby the slab is inspected for any signs of cracking or crazing. A loupe or magnifying glass may be used to get a better view of the surface.
    
    Apart from visual inspection, other methods used to diagnose delamination in the continuous casting slab of medium manganese wear-resistant steel include using a microscope, X- rays, and Ultrasound. In the microscope, small cracks and ridges on the surface of the slab can be seen. X-rays can be used for detecting subsurface cracks and flaws deeper within the slab. Ultrasound is used for detecting subsurface faults and porosity.
    
    Once the cause of delamination has been identified, it must be rectified. This can be done by resolving the source of imbalances in the internal and external forces which are causing the defects. This can be done through higher demand on production process control, making use of better quality raw materials, and improving process parameters like pouring temperature, cooling rate, and heat treatment.
    
    In summary, delamination is a defect that is commonly seen in the continuous casting slab of medium manganese wear-resistant steel. Visual inspection, microscopy, X-rays, and ultrasound are the most commonly used methods to detect and diagnose delamination. Once identified, the issue can be rectified by making sure that the production process is in control, and better quality raw materials are being used.

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