How to prevent the low hardness of the nitriding layer of Wuhan ionnitriding furnace

In production practice, the surface hardness of the workpiece after nitriding (soft nitriding) in the ion nitriding furnace sometimes does not meet the requirements of the process regulations, in this regard, the light can be reworked, but the heavy one will cause scrap, which brings great economic losses and affects our production development very much. So, how to prevent the low hardness of the nitriding layer of Wuhan ion nitriding furnace?
The low hardness of the ion nitriding layer will reduce the wear resistance of the workpiece and reduce the service life of the workpiece, and we will find the following reasons:
1) The nitrogen content of the surface layer of the nitriding mold is low, which is due to the high furnace temperature during nitriding or the high ammonia decomposition rate in the nitriding stage, that is, the nitrogen atmosphere in the furnace is too low.
2) The hardness of the substrate is too low after the mold is pre-heat-treated.
3) Poor sealing of the nitriding furnace, air leakage or new nitriding tank.
Precautions for low hardness of the nitriding layer of the ion nitriding furnace:
1) Reduce the nitriding temperature appropriately. The temperature control instrument should be calibrated frequently to maintain the appropriate nitriding temperature.
2) The workpiece should be heated slowly after being loaded into the furnace, the ammonia decomposition rate should be appropriately reduced in the first stage of nitriding, and the nitriding atmosphere all-factor monitoring system should be used to accurately restore the ammonia cracking rate, hydrogen content and nitrogen potential in the original atmosphere.
3) The ion nitriding furnace should be sealed, the muffle tank with leakage should be replaced in time, and the new nitriding tank should be pre-nitried, and the ammonia decomposition rate in the furnace should be stable through the whole process monitoring of the system.
The above is the introduction of the reasons for the low hardness of the nitriding layer of the Wuhan ion nitriding furnace and the preventive measures.