The following conclusions can be drawn from the work done:
1. From all the cold treatment schemes studied, it is not found that the cutting performance of the tool has any significant improvement over that of the tool with normal hardening and three times of firing.
2. Under the following conditions, cold treatment can significantly improve the cutting performance of the tool:
a) When the application of one-time fire distribution is (that is to use a fire distribution instead of multiple fire distribution);
b) When hardening from a lower temperature is (i.e. when the hardening temperature cannot be accurately controlled)
3. The cold treatment is only carried out in the hardening process because it can cause the transformation of residual austenite. There is no effect of cold treatment after fire mixing, because it can not cause more transformation of austenite.
4. The effect of cold treatment after hardening is the same as that of blending fire, which can actually replace the fire matching.
5. The application of cold treatment on high speed steel cutting tools can simplify and shorten the operation period of heat treatment, and can replace the three times of fire distribution with one time of fire distribution after one cold treatment.
The quality of a hardened tool can be improved at an average temperature of 70 ~ 60 ℃, because the tool quality can be improved at an average of 70 ~ 60 ℃. Cold treatment seems to correct the shortcomings of heat treatment (such as insufficient fire distribution and low hardening temperature). As a result of the work carried out, the most suitable cold treatment scheme has been determined, which consists of the following processes: 1) hardening; 2) cold treatment; 3) primary mixing