First, low pressure casting
At present, 90% of the factories in China's aluminum alloy wheel hub manufacturing industry use this process for production. The products produced by this process are mainly sold to OEMs and overseas retail markets.
The low-pressure casting process is currently quite mature in mainland China. Its advantages are moderate equipment cost, high production efficiency, high material utilization rate, and low production management. This process has been recognized by all OEMs. The aluminum alloy wheel hub manufactured by the low-pressure casting process, because the spokes are finally cooled and solidified, the spokes of some special modeling hubs are prone to quality problems such as shrinkage, and the rim portion has better strength due to the earliest crystallization.
Second, gravity casting
The most traditional casting process, currently about 15% of domestic enterprises still retain the industrial aluminum profiles of gravity casting production process, the products are mainly for domestic and overseas retail markets. The advantages of the process are low equipment cost, cheap mold, good product spoke quality; disadvantages are low metal utilization rate, low production efficiency, low cost performance, and most OEMs have rejected the wheel produced by the process, in aluminum wheels The manufacturing industry is gradually being marginalized.
Third, forging spinning
Compared with the high-end forming process, only about 10% of the domestic enterprises use this process for production. The products are mainly supplied to domestic and foreign buses, trucks and high-end sedan markets. The advantage is that the inherent quality of the product is good, the product strength is high quality and light; the disadvantage is that the equipment cost is high, and the spoke shape of the product manufactured by the traditional forging process can only be completed by milling processing, the metal utilization rate is low and the production efficiency is not high. Forging is divided into traditional forging and rolling forging, and the forging can directly forge the shape of the spokes.
Fourth, casting spinning
The casting spin is divided into two processes: "low pressure casting + spinning" and "gravity casting + spinning". At present, Korean car companies have adopted the trend of “low pressure casting + spinning” for the forming process of aluminum wheels. Some other cars have demand for this process. This process is the mainstream process in the spinning process, making OEM products. Most of the enterprises adopt this kind of technology; at the same time, a small number of enterprises doing overseas retail market adopt the process of “gravity casting + spinning”. In theory, this technology is a pass, it really puts The advantages of the two processes of gravity casting and spinning are combined and the quality of the product is improved. However, since the blank is produced by the gravity casting process, the economics of the process are very poor and the production cost is high. In short, the cast product, because the spoke portion is cast, has the same advantages and disadvantages as the product produced by the casting process; and the rim portion is spun out, so the airtightness is good. Casting products can theoretically reduce weight, but the effect is not obvious in practical applications.
Five, liquid die forging
At present, only two companies in the mainland are using this process for production, and the equipment and technology are from South Korea. In fact, the process is not forging. It should be classified into high-pressure casting. It is to directly inject a certain amount of aluminum alloy into the mold, and continuously apply mechanical static pressure to crystallize the metal under pressure and force the elimination of solidification and shrinkage. The shrinkage cavity is loosened to obtain a liquid die-forged aluminum alloy wheel blank without casting defects. Compared with the forging process, the industrial aluminum profile has the advantages of low equipment investment, direct rim formation, mechanical properties generally higher than ordinary castings, close to or even reaching the level of forgings, and it has no anisotropy usually found in forgings. The disadvantage is that liquid forged products, like traditional forged products, require milling to complete the spoke shape.
Sixth, differential pressure casting
At present, only a few companies in the mainland (mainly in Taiwan's Liuhe system) are using this technology, equipment and technology from Bulgaria. Differential pressure casting is a casting method derived from low pressure casting. The difference from low pressure casting is that the casting mold is placed in a sealed cover. The casting mold is under the pressure of the gas inside the sealed cover. When the pressure of the gas in the heat preservation furnace is greater than the pressure of the gas in the sealing cover, the industrial aluminum profile is crystallized and solidified under the action of higher pressure, so that the casting with higher density than the low pressure casting product can be obtained, and the yield is high. high. The disadvantage is the high cost of equipment and maintenance.