Understand the relevant dynamics of car brake discs

The brake hub is a vulnerable and consumable component. The market demand is particularly high. At present, the annual production in China is about ten million or more. Due to the relatively simple product structure, both machine and manual modeling are easy to implement, and almost all parts of the country have foundries producing brake hubs.

Due to different product structures and supply targets, production processes vary. However, overall, there are still many quality issues that cannot meet the quality requirements of automotive brake hubs. The production process of brake hub mainly focuses on two aspects, one is how to ensure its mechanical properties and metallographic structure meet product requirements. But how to reduce its casting defects. Especially for internal defects in key parts, in reducing casting defects.

One aspect is mainly to better provide the metallurgical quality of molten iron. Another aspect is to find suitable process methods for manufacturers. Due to the excellent thermal conductivity, shock absorption, wear resistance, excellent casting performance, and low manufacturing cost of gray cast iron, almost all brake hubs of motor vehicles are made of gray cast iron, with grades HT200 and HT250.

The internal shrinkage, porosity, and surface shrinkage of cast iron castings are largely influenced by the mold. After the molten iron is poured into the mold, the volume of the mold cavity will move under the static pressure and thermal action of the molten iron, causing the volume of the mold to increase, causing the size of the casting to exceed the tolerance and weight to increase. The size of the molding change depends on the compactness of the sand mold, the molding material, and the performance parameters of the molding sand. Before being transported to machining, the internal shrinkage of the brake hub is judged using the weighing method, and it is believed that the shrinkage of the brake hub is caused by the movement of the casting mold. Therefore, improving the stiffness of the mold becomes an important measure to avoid brake hub shrinkage and looseness.