How are the pores and slag inclusions in the coating produced?

       Pores are generated when the workpiece is not prepared properly, the oxygen content of the alloy powder is too high, the moisture in the gas, and the flame blowing force during remelting is too large. Slag inclusion is caused by the poor quality of alloy powder, such as high melting point, high viscosity, insufficient deoxidation ability and impurities in the powder. In addition, when the flame moves too fast during remelting, it is difficult for the slag to fully float out, which will also cause slag inclusion.



     Pores or slag inclusions will reduce the spraying quality and directly affect the wear resistance and corrosion resistance of the workpiece. It will also cause stress concentration and affect the strength of the workpiece.

     Spraying workpieces with pores and slag inclusions should be scrapped according to their working conditions. For workpieces with wear-resistant requirements, the coating should have no more than 5 pores or slag inclusions with a diameter of less than 0.04mm in an area of 1cm2.