The interaction between aluminum alloy and
die casting mold, and the temperature of operation interface is the key factor to interfere with AR / AA ratio. When the atomic structure of the operation interface interacts with each other, the value of AR / AA increases with the increase of temperature. The operation interface temperature is mainly the interference of the internal surface layer of the pressure mold and the temperature of the aluminum alloy. The casting temperature is the key technical factor to interfere with the operation interface temperature. The higher the casting temperature is, the higher the operation interface temperature is, and the easier the welding is. In addition to being disturbed by the casting temperature, the temperature of the inner surface of the die casting mold also needs to be disturbed by the structure of the die casting mold and the necessary conditions for cooling. If the cooling system layout of the die casting mold is unscientific, the operating temperature of the die casting mold is too high, or the cooling of the die casting mold is uneven, so that the welding is very easy to occur when the temperature of the die casting mold is close to the critical temperature.
Disadvantages and characteristics:
There are other problems on die cast
aluminum castings. When they are more serious, they are mainly manifested in the cracking of parts. Cracks are usually waste. The cracks on it can be divided into hot cracks and cold cracks. Hot cracking is caused at a higher temperature, that is, in the whole process of forming. There is air oxidation on both sides of the crack, and the color is a little darker. The cold crack occurs after the casting is cooled, and the tone of the side of the crack is no different from that of the casting itself.
Cause：
The reason for the hot crack is that the temperature of the liquid metal material is too high, the solidification is not enough, the mold is opened too early, or the closing is blocked and the overall temperature of the mold is unbalanced. It may also be that the inclination of the mold is too small and the parts are bruised, resulting in cracks. Cold crack is the crack caused by excessive internal stress in parts at room temperature.
Avoidance Countermeasures：
Properly reduce the liquid metal temperature, preheat the mold and balance the mold temperature, and do not open the mold too early; The surface of the cavity should be smooth and smooth to reduce the resistance of some fluidity, which can help avoid thermal cracks. Avoiding cold cracks is usually considered in the structure of castings, at the junction of face to face and line to line of aluminum die castings.
Ningbo Fuerd was founded in 1987, is leading full-service
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