When it comes to the all-aluminum body of a car, the inescapable feature is "lightness". Except for those expensive top supercars that use a lot of carbon fiber, the lightweight design of cars is mostly achieved by the use of aluminum alloys in a large proportion.

However, this does not mean that aluminum alloys are cheap. In fact, the all-aluminum body has another feature that is "expensive". This is not only the higher cost of the material itself, but also the cost of the manufacturing process with a higher threshold. Therefore, models that can use all-aluminum bodies may not reach the level of supercars, but they are not "economical". (For example, Audi's ASF all-aluminum frame was only used on the previous generation A8, and other models below could not afford this cost, and the latest generation of A8 also gave up the concept of "all-aluminum", where they felt appropriate. High-strength steel is also used)

However, the above two are only the well-known features of aluminum alloys. It is far more than that simple to elaborate, and some other features of the all-aluminum body are also closely related to these two features.

What is an all-aluminum body? Is it really 100% aluminum?

In fact, the concept of all-aluminum body means that the body structure is mainly made of aluminum alloy, which not only allows the existence of some non-aluminum parts, but also aluminum appears in the form of alloy here.

Aluminum alloy does not refer to an alloy, in fact, there are quite a few categories. The international rule is to use a four-digit number plus a letter to distinguish the type of aluminum alloy, such as 6063-T5 commonly used in the construction industry. , the first digit is 1, it represents pure aluminum with a purity higher than 99%, 2-8 represent alloys composed of aluminum and copper, manganese, silicon, magnesium, magnesium + silicon, zinc and other elements, 9 is the spare group . The following numbers are mainly used to distinguish, and the specific logic will not be repeated. In short, each formula of aluminum alloy has a unique label, corresponding to its unique characteristics. At present, the 5 series and 6 series are mainly used in the all-aluminum body of automobiles, which are materials with low density, good tensile strength and fatigue resistance, and can achieve higher strength at a much lower weight than steel, including Audi ASF all-aluminum body and so on are widely used. In addition, the 2 series and 7 series also have a small amount of applications. The 2 series copper aluminum alloy has high hardness and will be used in some body sheet metal parts; the 7 series is mainly used in the aviation and military fields, which are superhard, corrosion-resistant and wear-resistant. Of course, the price is also very touching. At present, the domestic 7 series aluminum materials mainly rely on imports, but the ES8 body-in-white longitudinal beams released by Weilai some time ago use 7003 aluminum materials. There are also some special aluminum castings (HPDC) that have many applications.

Different aluminum alloys have different characteristics, but the aluminum alloys used in the structural field have a common feature: high strength, and their hardness is generally stronger than that of stainless steel of the same specification. After coating and drying, the yield strength is above 200Mpa, and SPCC/DC04 is also 150-160Mpa. In addition, the all-aluminum body is not a whole. Different types of materials will be distributed according to the force of different parts of the body. Generally, they will be connected by self-piercing rivets, laser welding, gluing, etc. It is said that the whole body will be scrapped after hitting it. It is not true, the damaged part can be replaced by professional tools, of course it is more expensive.