The special slag-locking valve for coal chemical industry has attracted much attention from the industry because of its critical location, high technical requirements and expensive cost. It can be used under very harsh working conditions.Its characteristics are: 1. The sealing specific pressure is high; 2. The surface hardness of the sphere is high; 3. The binding strength of the spray welding layer is high; 4. The self-cleaning function; 5. The processing is difficult.