Induction annealing equipment must meet several conditions if it is repelled: 1. Suitable temperature. 2. The appropriate rate (mainly allows the workpiece to be fully heated in the high temperature zone and cold in the low temperature zone). 3. Suitable ammonia flow rate and ammonia decomposition quality. 4. Guarantee the integrity of the muffle can. 5. Ensure the uniformity of ammonia in the muffle tank.