In the continuous production process of the mold, due to prolonged contact with the blank with higher temperature than itself, the temperature of the convex and concave molds continuously increases, and the strength and hardness decrease sharply, thereby affecting the life of the mold. At the same time, under the high extrusion stress, the mold after the temperature rise is more likely to be deformed, which will seriously affect the shape and dimensional accuracy of the extrusion. Therefore, in the mold structure should be considered to set the cooling device or continue to use artificial cooling method, so that the mold temperature is maintained in the range of 150 ~ 300 °C.
In small batch production, after each forming, the working parts such as male and female molds can be cooled with compressed air, or the time interval for warm forging can be increased.
In large-scale production, special measures should be taken to ensure that the mold temperature is stable within the preheat temperature range. The specific measures are as follows.
First,when using a mechanical press for continuous production, the number of strokes per unit time can be appropriately adjusted to ensure sufficient time for the mold to cool.
Second,open the hole in the mold to strengthen the internal cooling, such as pumping the lubricant with pressure of 0.12~0.14 MPa into the hole in the mold to exile to cool the punch, and blow the pressure in the die to 0.4~0.5 MPa. Compress air to cool the die and ejector.
Third，the spray cooling of the mold mainly considers where the lubricant cannot flow due to the rapid evaporation of water.
Fourth,mold set water cooling device.
The above four methods can be used in combination to produce better results.