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Four forging methods for fuel-efficient and durable aluminum wheels

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Update time : 2020-07-24 15:59:27
Conventional forging
 Forging is one of the earlier forming processes for aluminum wheel applications. Forged aluminum wheels have the advantages of high strength, good corrosion resistance, accurate size, and small processing capacity. Generally, the weight is only 1/2 or less of the same size steel wheel. The grain flow direction of the forged aluminum wheel hub is consistent with the direction of the force, and its strength, toughness and fatigue strength are significantly better than cast aluminum wheels.
At the same time, the performance is very reproducible and almost every hub has the same mechanical properties. The typical elongation of forged aluminum wheels is 12% to 17%, so it can absorb the vibration and stress of the road. Casting hubs are generally quite resistant to compressive forces, but are less able to withstand impact, shear and tensile loads than forged aluminum wheels. Forged wheels have a higher strength to weight ratio.
In addition, the surface of the forged aluminum hub has no air holes, so it has a good surface treatment ability, which not only ensures uniform coating, but also a firm combination and good color. The biggest disadvantage of forged aluminum wheels is that there are many production processes and the production cost is much higher than that of casting.
 
Casting forging

 It is a method in which a casting is used as a blank for a forging process and plasticized. Since the forging is used as the final forming step of the part, the casting defects can be eliminated, the structure of the product can be improved, the mechanical properties of the product can be greatly improved compared with the casting, and the advantages of the casting process in forming complex parts can be fully utilized, and the shape is complicated. The product forging process is reduced, the material utilization rate is greatly improved, and the production cost is lowered.
The aluminum wheel hub is produced by casting forging technology, and its performance can fully reach the mechanical performance index of forgings, but the production cost can be reduced by 30% compared with ordinary forged parts. At present, the process has been successfully applied to mass production since September 1996, and has been adopted by many Japanese companies with good economic results. At present, only a few companies in the mainland (mainly in Taiwan's Liuhe system) are using this technology, equipment and technology from Bulgaria.
 
Semi-solid die forging process
 The so-called semi-solid die forging is a process in which a semi-solid billet is heated to a semi-solid state with a liquid phase of about 50% and then subjected to one-time die forging to obtain a desired close-sized finished part, which is a kind of solid-state forming and A new process between liquid forming.
Advantages of semi-solid die forging: the parts shrink less in the mold, easy to be near-final forming, and the machining amount is reduced; the surface of the semi-solid die forging is smooth and smooth, the internal structure is dense, the grain is fine, and the mechanical properties are higher than die casting and extrusion. Casting parts; forming is not easy to wrap, macroscopic pores and microscopic porosity are much less than in conventional castings; forming temperature is low and mold life is long.
In the past 10 years, semi-solid forming technology has been widely used in foreign countries, and has gradually become a new field for the development of advanced industrial countries. It has been called a new generation of emerging metal forming technology in the 21st century by experts and scholars. It is expected that for a long period of time, the main market for semi-solid forming is the automotive industry, and the most successful and widely used automotive aluminum alloy parts.
Several aluminum alloy semi-solid die forging plants have been built in the United States. Among them, the American company AEMP cooperated with Superior Industrial Company in Arkansas in 1992 to build the world's first semi-solid die-wrought aluminum alloy automobile wheel factory. The use of semi-solid die forging instead of low-pressure casting to produce ZL101 aluminum alloy wheel hubs not only reduces machining and productivity, but also improves mechanical performance and quality.
 
Forging spinning
Compared with the high-end forming process, only about 10% of 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.