Cause analysis of white spots on wear-resistant steel surface after milling

    
    White spots on the wear-resistant steel surface after milling can be attributed to the presence of oxidation layer or decomposition layer on the surface of the steel. The thermal energy generated by the milling process, combined with the chemical reaction between oxygen and the lubricant, induces oxygen and lubricant molecules to react with the surface of the steel, forming oxide and oxide-based products, such as a thick oxide layer. The oxide layer, due to its poor adhesion to the surface of the steel, can easily be worn away, leaving white spots.
    
    White spots on wear-resistant steel surfaces also occur due to weak adhesion of the abrasive grains to the surface of the steel, during milling. The contact between the abrasive and steel surface generates a certain degree of frictional heat and pressure, resulting in the melting and softening of the steel surface. Due to the poor adhesion of the abrasive to the steel surface, the grains become detached and leave behind white spots.
    
    Moreover, white spots may also occur due to the presence of flux residues on the workpiece surface. The flux added to the cutting fluid may react with the steel surface and form an oxide layer or oxide-based products. The oxide layer, due to its poor adhesion to the surface of the steel, can easily be worn off, leaving white spots.
    
    To address these issues and prevent the formation of white spots on wear-resistant steel surfaces after milling, the following precautions should be taken:
    
    1) Regularly check and maintain the cutting tools to ensure that they are free from grit, dust, and oxidation that can reduce adhesion between the abrasive particles and the steel.
    
    2) Use a low-temperature cutting fluid containing a high-performance lubricant or a minimum quantity lubrication (MQL) system to reduce thermal load on the wear-resistant steel surface.
    
    3) Select an appropriate feed rate and spindle speed to prevent excessive heat generation.
    
    4) Regularly clean the workpiece surface before and during machining.
    
    5) Pay particular attention when milling alloy or stainless steel material, due to the presence of chromium in the steel which makes adhesion of the abrasive difficult.
    
    6) Install a filtration system on the cutting machine to remove small particles and dust that can accumulate on the cutting tool and reduce adhesion of the abrasive particles.
    
    7) Inspect the workpiece surface after machining to ensure that no residue is left behind.
    
    By following these steps and using the right milling techniques and materials, white spots on wear-resistant steel surfaces can be effectively reduced or eliminated.

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