First, that the tower wheel is used in what conditions should be noticed. If it is used in common tungsten wire, molybdenum wire and other production industries, it is recommended to use supersonic flame spraying tungsten carbide coating. This process is mature and used by many manufacturers. If it is necessary to use laser melting coating, the stability of laser power should be considered first, as well as the time for measuring hardness. The hardness should be measured after the workpiece is completely cooled to room temperature. The common hardness meters similar to the outer surface of the tower wheel cannot completely and accurately measure the hardness. To measure the hardness, the same parameter test block should be made for testing.