Aluminum alloy die-casting process knowledge

1) Aluminum alloys can be divided into four types according to their performance characteristics and uses:

Rust-proof aluminum (LF), hard aluminum (LY), super hard aluminum (LC) and forged aluminum (LD)

2) Cast aluminum alloys can be divided into four types according to the addition of main alloying elements:

Aluminum silicon system (AL-Si), aluminum copper system (Al-Cu), aluminum magnesium system (Al-Mg) and aluminum zinc system (Al-Zn)

Common grades are ADC12 (A383), ADC10 (A380)

3) Advantages of aluminum alloy die-casting

Good product quality: high dimensional accuracy of castings, good surface finish, high strength and hardness, the strength is generally 25~30% higher than sand casting, but the elongation is reduced by about 70%, the size is stable, and the interchangeability is good. Thin-walled and complex aluminum castings can be die-cast, for example: the current minimum wall thickness of zinc alloy die-casting can reach 0.3mm, and aluminum alloy die-casting can reach 0.5mm. High production efficiency: The machine has high productivity. For example, the domestic JⅢ3 horizontal cold air die-casting aluminum machine can die-cast aluminum 600 to 700 times in eight hours on average, and the small hot chamber die-casting aluminum machine can die-cast aluminum 3,000 to 7,000 times every eight hours on average. Excellent economic effect: Due to the advantages of die-casting aluminum parts such as precise size and smooth surface. Generally, they are used directly without mechanical processing, or the processing volume is very small, so it not only improves the metal utilization rate, but also reduces a large number of processing equipment and working hours. The casting price is cheap, and combined die-casting aluminum can be used with other metals or non-metallic materials, which saves assembly time and metal.

4) Disadvantages of aluminum alloy die-casting

During die-casting, due to the high speed of liquid metal filling the cavity and the unstable flow state, the general die-casting aluminum method is used, and the casting is prone to pores and cannot be heat treated. For castings with complex concave, die-casting is more difficult. The life of aluminum alloy die-casting molds is low, and the life is about 80,000 times. It is not suitable for small batch production. The main reason is that the manufacturing cost of die-cast aluminum molds is high and small batch production is not economical. Aluminum alloy die-casting is not easy to achieve anodization. Since many bubbles or sand holes are easily left after die-casting, the appearance cannot be well repaired, and the appearance cannot be covered after oxidation.

Note: Here we focus on the number and life of aluminum die-casting molds, the grade of die-cast aluminum, and the reasons why the appearance cannot be oxidized.

Die-casting molds must be made of hot mold steel. Commonly used steels are: H13, 8407, 2344, 8418, SKD61, DAC, FDAC, etc. After the product is formed, subsequent water inlet punching, removal of burrs, tapping, thermal shaping, etc. are required to obtain the primary product that meets the design requirements.

Tips:

1) When designing the structure of aluminum alloy die-castings, try to design as few inclined top structures as possible to prevent the subsequent removal of burrs from being difficult.
2) When designing the structure of aluminum alloy die castings, it is also necessary to pay attention to the uniform thickness of the glue and the smooth flow of the glue, which can reduce many problems such as poor appearance caused by molding and increase subsequent polishing and re-inspection.
3) When designing the load-bearing structure, it is still necessary to consider the structural strength, otherwise it is easy to break.