automobile making

Four forging methods for fuel-efficient, durable, and aesthetically pleasing aluminum wheels
 

Conventional forging

Forging is one of the early forming processes for aluminum wheel hubs. Forged aluminum wheels have advantages such as high strength, good corrosion resistance, precise dimensions, and small processing volume. Generally, their weight is only half or less of that of steel wheels of the same size. The grain flow direction and stress direction of forged aluminum wheels are consistent, and their strength, toughness, and fatigue strength are significantly better than those of cast aluminum wheels.

At the same time, the performance has good reproducibility, and almost every wheel hub has the same mechanical performance. The typical elongation of forged aluminum wheels is 12%~17%, which can effectively absorb road vibration and stress. Usually, cast wheels have a strong ability to withstand compressive forces, but their ability to withstand impact, shear, and tensile loads is far inferior to forged aluminum wheels. Forged wheels have a higher strength to weight ratio.

In addition, the surface of the forged aluminum wheel hub has no pores, so it has good surface treatment ability, which not only ensures uniform and consistent coating, firm bonding, but also good color. The biggest drawback of forging aluminum wheels is that there are many production processes and the production cost is much higher than that of casting.

Forging method

It is a method of plastic processing by using castings as blanks in the forging process. Due to the use of forging as the final forming process of parts, casting defects can be eliminated, the organizational structure of products can be improved, and the mechanical properties of products can be greatly improved compared to castings. At the same time, the advantages of casting technology in forming complex parts can be fully utilized, reducing the forging process of products with complex shapes, greatly improving material utilization, and reducing production costs.

The production of aluminum wheels using casting and forging technology can fully meet the mechanical performance indicators of forgings, but the production cost can be reduced by 30% compared to ordinary forged parts. At present, since its successful application in batch production in September 1996, this process has been adopted by multiple Japanese companies with good economic results. At present, only a few enterprises in mainland China (mainly in Taiwan's Liuhe System) are adopting this process, and the equipment and technology come from Bulgaria.

Semi solid forging process

　　The so-called semi-solid die forging refers to the process of heating a semi-solid billet to a semi-solid state with a liquid phase of about 50%, and then forming it in one die forging to obtain the required size of finished parts. This is a new process between solid forming and liquid forming.

The advantages of semi solid die forging: the shrinkage of the parts in the mold is small, and it is easy to form near the end, reducing the amount of mechanical processing; The surface of semi-solid die forgings is flat and smooth, the internal structure is dense, the grains are small, and the mechanical properties are higher than those of die-casting and squeeze casting parts; Forming is not easy to wrap air, and macroscopic pores and micro porosity are much less than those in conventional castings; Low forming temperature and long mold life.近10年来，半固态成形技术在国外获得了广泛的应用，已逐步成为各

A new field that advanced industrial countries are competing to develop is called the emerging metal forming technology of the 21st century by experts and scholars. It is expected that for a considerable period of time, the main market for semi solid forming will be the automotive industry, with the most successful and widely used being automotive aluminum alloy parts.

Several semi-solid die forging factories of aluminum alloy have been built in the United States, among which AEMP and Superior Industries in the United States established the world's first semi-solid die forging aluminum alloy automobile hub factory in Arkansas in 1992. Replacing low-pressure casting with semi-solid forging to produce ZL101 aluminum alloy car wheels can not only reduce mechanical processing and improve productivity, but also improve mechanical performance and reduce mass.

Forging spinning

　　A relatively high-end forming process, currently only about 10% of domestic enterprises use this process for production, and the products are mainly supplied to the domestic and international markets of buses, trucks, and high-end sedans. The advantage is that the product has good internal quality, high strength, and light weight; The disadvantage is that the equipment cost is high, and the spokes of products manufactured by traditional forging processes can only be completed by milling, resulting in low metal utilization and low production efficiency. Forging is divided into traditional forging and rolling forging, and rolling forging can directly forge the shape of the spoke.