Hardening method of metal hard sealed ball valve balls and valve seats
At present, the commonly used hardening processes for the surface of metal hard sealed ball valves mainly include the following: (1) Surface welding (or spray welding) of hard alloy on the sphere can achieve a hardness of over 40HRC. The process of surface welding of hard alloy on the sphere is complex, with low production efficiency, and large area welding can easily cause deformation of the parts. Currently, there is relatively little use of surface hardening technology on the sphere. (2) The surface of the sphere is plated with hard chromium, with a hardness of 60-65HRC and a thickness of 0.07-0.10ram. The chromium plating layer has high hardness, wear resistance, corrosion resistance, and can maintain surface brightness for a long time. The process is relatively simple and the cost is relatively low. However, the hardness of the hard chromium coating will rapidly decrease as the temperature increases due to the release of internal stress, and its working temperature cannot exce