Processing and heat treatment of automobile aluminum die casting parts

The major aluminum alloy die casting parts of Sieg-Huao are applied in automotive industry which includes automobile air-conditioning, automobile wiper system, fuel filter system, charging system, car rearview system, automobile steering system and commercial vehicle brake system. Today our topic is the processing and heat treatment of automobile aluminum die casting parts. 

The metal copper, zinc, aluminum and aluminum alloy have good flowability and plasticity, and casting process is done in pressure die casting machine, for that reason aluminum die casting can make all kinds of complicated shapes, can also achieve higher precision and smoother finish, thus greatly reduce the mechanical processing capacity of the casting and the casting allowance of metal copper, zinc, aluminum or aluminum alloy. The structure design of automobile aluminum die casting parts should not only meet the requirements of machine equipment and machining technology, but also meet the requirements of casting technology. Therefore, the following points are summarized for your reference.

1. Convex platform on the casting parts and casting body should not differ too much, it is best to take the same height. For the convex sets which are close to each other in the same surface level, it is best to connect the raised part of the whole.

2. The shape of the castings shall be as simple as possible in order to achieve easy rapping of die casting parts. The joint face of casting parts shall be as flat as possible and the number shall be minimized.

3. The internal cavity of the casting shall be cast with no or less cores. When using cores, it shall be convenient to support, fix and vent sand, and sufficient process holes shall be provided if necessary.

4. For the internal and external profile and strengthening rib structure of the casting parts, a certain structural slant should be set in the direction of the rising die. .

The heat treatment of automobile aluminum die casting is to control the heating temperature, heat preservation time and cooling speed according to a certain heat treatment specification and change the structure of the alloy. Its main purpose is to improve mechanical performance, enhance corrosion resistance, improve processing performance and obtain dimensional stability.

The heat treatment process of aluminum alloy die casting is as follows:

1. Annealing process heats aluminum alloy die casting parts to a high temperature which is about 300 ℃ and preserve heat  for some certain amount of time, and cool to room temperature along with the furnace. In the process of annealing, the solid solution is decomposed and the second phase particle is aggregated, which can eliminate the internal stress of the casting, stabilize the size of the casting, reduce the deformation and increase the plasticity of the casting. 

2. The solid solution treatment heats the casting to the highest possible temperature which is close to the melting point of the eutectic, maintains at this temperature for a long enough time, and then cools quickly to allow maximum dissolution of the strengthened elements. This high temperature state is fixed and stored at room temperature, which is called solid solution treatment. Solid solution treatment can improve the strength and plasticity of casting and improve the corrosion resistance of alloy.