New lightweight materials for automobiles - part 1

Main ways of automobile lightweight

① The main specifications of automobile models are continuously optimized. On the premise of retaining the main parameters of specifications, the structural strength of the whole vehicle is improved and the consumption of consumables is reduced;

② Use light materials. Such as aluminum, magnesium, ceramics, plastics, glass fiber or carbon fiber composites;

③ Computer is used for structural design. Such as finite element analysis, local strengthening design, etc;

④ Adopt load-bearing body, reduce the thickness of body sheet, etc.

Among them, the current main vehicle lightweight measures are mainly the use of lightweight materials.

The lightweight of the car is to reduce the servicing quality of the car as much as possible on the premise of ensuring the strength and safety of the car, so as to improve the power of the car, reduce fuel consumption and reduce exhaust pollution. Experiments have shown that if the vehicle mass is reduced by half, the fuel consumption will also be reduced by nearly half. Due to the needs of environmental protection and energy conservation, the lightweight of cars has become the trend of the world's automobile development.

Basic information of vehicle lightweight

Main guiding ideology: on the basis of ensuring stable and improved performance, energy-saving design of various assembly parts and components, and continuous optimization of the model spectrum.

Experiments show that if the weight of the whole vehicle is reduced by 10%, the fuel efficiency can be increased by 6% - 8%; The fuel consumption per 100 kilometers can be reduced by 0.3-0.6 liters for every 100 kilograms of vehicle curb weight reduction; The vehicle weight is reduced by 1%, and the fuel consumption can be reduced by 0.7%. At present, due to the needs of environmental protection and energy conservation, the lightweight of cars has become the trend of the world's automobile development.

Automotive materials mainly contribute to the improvement of fuel economy through the lightweight of vehicles. Theoretical analysis and experimental results show that lightweight is an effective way to improve vehicle fuel economy. In order to meet the requirements of automobile lightweight, some new materials came into being and expanded the scope of application.

Nonferrous Alloy

For passenger cars, the weight ratio of non-ferrous alloys used in each car to all materials was 5.0% in 1973, increased to 5.6% in 1980, and reached 9.6% in 1997. The rapid growth of the application of non-ferrous alloys in automobiles is the general trend of the development of automotive materials.

Aluminium alloy

The density of aluminum is about 1/3 of that of steel, which is the most widely used lightweight material. Take the automobile products produced in the United States as an example. In 1976, the aluminum alloy for each vehicle was only 39kg, in 1982 it reached 62kg, and in 1998 it reached 100kg.

(1) Cast aluminum alloy

Many elements can be used as alloying elements of cast aluminum alloys, but only Si, Cu, Mg, Mn, Zn, Li are of great significance in mass production. Of course, it is not the above simple binary alloys that are widely used in automobiles, but a variety of elements are added at the same time to obtain good comprehensive properties.

Automobile industry is the main market of aluminum castings. For example, in Japan, 76% of aluminum castings and 77% of aluminum die castings are automobile castings. Aluminum alloy castings are mainly used in engine cylinder block, cylinder head, piston, intake manifold, rocker arm, engine mounting bracket, air compressor connecting rod, driver housing, clutch housing, wheel, brake parts, handle and cover housing parts, etc.

There are inevitable defects in aluminum castings, and the die castings cannot be heat treated, so it is limited to produce castings with high strength with aluminum alloy. Therefore, the casting production process has been improved. Casting forging method and semi-solid forming method will be more used in the future.

(2) Wrought aluminum alloy

Wrought aluminum alloy refers to aluminum alloy plate, strip, extruded profile and forged material. It is mainly used in automobile body panels, body frames, engine radiators, air conditioning condensers, evaporators, wheels, decorative parts and suspension system parts.

Due to the obvious lightweight effect, the application of aluminum alloy in car bodies is expanding. For example, the Japanese Honda NSX car, which was sold in September 1990, adopts an all aluminum load-bearing body, which is 200kg lighter than the same body made of cold-rolled steel plate, attracting worldwide attention. NSX aluminum materials for all vehicles reach 31.3%. For example, on the all aluminum body, the outer plate uses 6000 series alloy, the inner plate uses 5052-0 alloy, and most of the skeleton uses 5182-0 alloy; Because the side door frame has high requirements for strength and stiffness, an alloy based on 6n01 alloy with appropriate adjustment of Mg and Si content is used. In Europe and America, 2036 and 2008 alloys are also used as body inner and outer panels.

Aluminum radiator originated in Europe and then spread all over the world. In Europe, by the late 1980s, aluminum radiators had occupied 90% of the market. With? With the extensive use of automotive air conditioners and oil coolers, the market of aluminum heat exchangers has expanded rapidly. From the perspective of materials, the wide application of aluminum in heat exchangers is largely due to the successful development of clad aluminum plates and strips.