What technical standards should be formulated for the entire spraying process during coating design?

       At the same time of coating design, it is necessary to put forward the corresponding technical conditions so that the process and inspection department can implement it.

    There is still a lack of a unified method for formulating technical conditions for spraying. The main contents of spraying technical conditions for general workpieces are introduced here.

    (1) Specifying the grade of alloy powder and the corresponding macro hardness can generally judge whether the process is normal or not.

    (2) The surface quality of the spray coating shall be specified. For example: the surface is required to be smooth, the color is uniform, condensation and coating peeling are not allowed, and there are no defects such as pores, slag inclusions, cracks, and pinholes. For pores and slag inclusions, corresponding regulations are made depending on the importance of the workpiece. When the workpiece is only subject to wear, a single blowhole or slag inclusion can be tolerated. If corrosive medium acts, defects such as pores are not allowed.

    (3) When the workpiece needs heat treatment, it is necessary to specify whether it is heat treatment before spraying or heat treatment after spraying.

    (4) If finishing is required after spraying, the surface quality after processing is also stipulated. For example, the defects pointed out in item (2) are not allowed to exist, and the unprocessed surface of the sprayed layer is not allowed to exist. For the thickness of the coating, corresponding provisions should also be made, such as the allowable range of the coating thickness, or the non-uniformity in the thickness of the coating should be specified. In addition, the roughness of the machined surface is also specified.

    (5) Large batches of workpieces require stable quality, and the bonding strength indicators, test methods and random inspection ratios must be specified.