1、 Low hardness

The large amount of retained austenite is one of the reasons for the low hardness of the stamping die. The large amount of retained austenite in the carburizing layer is often due to the high carburizing temperature and the high surface carbon concentration. The low surface carbon concentration is another reason for the low hardness of the stamping die. The low surface carbon concentration is caused by the low carburizing temperature; Low carburizing gas flow; The vacuum quenching oil absorbs a large amount of air; Other oils, such as cylinder oil, are mixed with vacuum quenching oil.

2、 The depth of carburized layer fails to meet the requirements of technical conditions

The reason why the carburizing layer depth of the stamping die exceeds the requirements is that the carburizing temperature is high or the carburizing time is long, and the reason why the depth is lower than the requirements of the technical conditions is that the carburizing temperature is low or the carburizing time is short.

3、 The carburized layer of the stamping die itself is uneven

The reasons for this may be: air is mixed in the carburizing gas; Pulse carburizing is not used; Carburizing gas pressure is too low; Too much charging and too dense; Carburizing gas is of low purity and produces more carbon black.

4、 There is a lot of carbon black, and the stamping die is also attached with carbon black

When a large amount of carbon black is produced in the carburizing process, it may cause electric short circuit between heater and furnace body, heater and heater, and increase the maintenance workload of equipment; The holes of the stamping die are blocked, the carburizing layer is uneven, and the workload of removing carbon black on the surface of the parts is increased.

5、 Deterioration of brightness of stamping die

After vacuum carburizing and air cooling, the stamping die shall be silvery white when it is discharged. If the brightness of the parts deteriorates when it is discharged, the reason may be that the furnace has a large leakage; The vacuum quenching oil is mixed with more air; The purity of cooling gas (such as nitrogen) is not high, which contains more oxygen; More cylinder oil is mixed with vacuum quenching oil.