Preheating Requirements of Aluminum Castings And Rational Use of Aluminum Molds

Aluminum castings need to be preheated before use. Aluminum molds must be preheated to a certain temperature before use. Preheating can prolong the service life of the die. Usually, electrical appliances or induction heating are used for preheating. The preheating temperature is controlled at 250℃ ~ 300℃. Keep the temperature for about 0.5h, and it can be used. It is forbidden to use molten metal to directly preheat the mold, because the cold mold is in direct contact with hot liquid metal, which will inevitably be subjected to thermal shock, thus leading to thermal corrosion and accelerating the cracking and peeling caused by thermal fatigue.

In the process of manufacturing aluminum castings, the surface treatment quality of mold cavities can be effectively improved. There should be no obvious traces of deep processing tools on the surface of the mold cavity to prevent the mold from cracking due to stress concentration during the mold finishing process. The surface of the cavity should be effectively polished and ground to control the surface roughness of the cavity below 0.8 μ m.

In continuous production, the temperature of aluminum casting mold has an upward trend. Excessive temperature will not only lead to the formation of boulders in liquid metal, but also slow down the cooling rate of castings, resulting in coarse grains and poor quality of aluminum castings. Therefore, when the temperature of aluminum casting die is too high, cooling measures should be taken. Compressed air or water is usually used for cooling. Casting aluminum molds are usually designed with a cooling system to ensure the thermal balance of the molds.

After the aluminum casting die is used, the die cavity should be cleaned in time to remove the residual aluminum effectively. After cooling, it should be rusted and put into the warehouse for centralized management for reuse. At the same time, by grasping the design, manufacture, use, maintenance and management of the mold, the service life of the aluminum casting mold can be effectively extended, thus reducing the manufacturing cost of the motor.