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Alloy Wheels Light Weight, High Manufacturing Accuracy
Sep 29, 2017

The current alloy wheels as a commonly used wheels in a variety of models are almost used, the advantages of alloy wheels:

1 energy saving: alloy wheels of light weight, high precision manufacturing, high-speed rotation in the small deformation, inertia resistance is small, is conducive to improving the car's straight line performance, reduce tire rolling resistance, thereby reducing fuel consumption.

2 safety: aluminum thermal conductivity is three times the steel, cooling effect is very good, thereby enhancing the braking performance, improve the tire and brake disc life, effectively protect the car's safe driving.

3 comfortable: equipped with alloy wheels of the car are generally used cushioning and shock absorption performance is better than ordinary tires flat tires, so that the car on the uneven road or high-speed driving, the comfort greatly improved. Low-pressure casting can achieve a high degree of mechanization, automation, both to improve productivity (10-15 / h), but also reduce the number of human factors are not conducive to the production process to improve the yield, and can greatly reduce the labor intensity of workers. However, the quality of low-pressure casting parts such as process solutions, process parameters, mold structure and manual operation and other factors, and their mutual influence, any one of the irrational design or improper operation may lead to defects in low-pressure casting parts. Among them, the formation of aluminum alloy wheel corrosion is the impact of production costs, production efficiency of the important factors. Therefore, it is very important to study the causes of crack initiation of low-pressure cast aluminum alloy wheels.

In the sealed liquid containing metal liquid into the dry compressed air, the role of maintaining a certain temperature on the metal surface, the metal liquid along the riser from bottom to top through the runner into the cavity, to be metal After filling the cavity, increase the pressure,Alloy Wheels  the cavity of the molten metal in a certain pressure under the action of solidification forming, and then lift the liquid pressure on the liquid, so that the liquid tube is not solidified liquid fall into the pot, and then open Type pickup.

Mainly in the stress concentration of the site, or wheel Yi mold release due to uneven force, or the liquid tube caused by liquid coagulation cracking. Cracks are generally divided into two types: cold cracking and thermal cracking.

Cold cracking refers to the formation of cracks in the alloy below its solidus temperature. In layman's terms, cold cracking is caused by the casting stress acting on the casting over the strength or plasticity of the casting itself when the casting is cooled to a low temperature. The cold cracking is mostly present on the surface of the casting, and the surface of the crack is slightly oxidized. The hot cracking is usually considered to be caused during the solidification of the alloy. The casting always solidifies from the surface due to the heat transfer of the wall. When the casting surface appears a large number of dendrites and lap into a complete skeleton,Alloy Wheels  the casting will appear solid shrink (often in line contraction). But there is still a layer of dendrites between the liquid metal film (liquid film), if the casting shrinkage without any hindrance, then the dendritic layer is not the role of force, can be free to shrink, it will not appear stress. When the shrinkage of the dendrites is hindered, it is not free to shrink or be subjected to tensile forces, and tensile stress occurs, and the liquid film between the dendrites is deformed by stretching. When the tensile stress exceeds the strength limit of the liquid film, the dendrites will be opened. However, there are some liquid metal around the cracked part. If the liquid film is pulled at a very slow speed and there is enough liquid around it and flows into the cleavage in time, the cleavage will be filled and "healed" No hot cracks will occur. If the rupture can not be re-"healing", the casting will be hot cracks. The surface of the hot crack fracture is strongly oxidized, showing a metallic luster of dark or black.