Classification of vehicle body coverings systems and aluminum alloy die castings

I. Auto body coverings system
From the wave of automotive lightweighting in the early 21st century, the lightweighting of body and coverings has been the main character. Starting from the introduction of all-aluminum body by Audi, the lightweight body has been synonymous with the lightweighting of automobiles. As countries pay more and more attention to energy saving and emission reduction, the trend of lightweighting will continue. New energy vehicles and intelligent driving vehicles, automotive lightweighting has risen to a new level, especially the power battery system weight problem is difficult to solve in a short period of time, so lightweighting has taken on the difficult task of increasing the range. From the perspective of the major new energy car companies, most of the newly launched models are all-aluminum body, the main reason is the huge contribution of lightweight alloy parts to the weight reduction of the body.
From the point of view of body parts, the major car companies, especially the medium-sized models have generally accepted high-pressure casting structural parts as a solution for the integration/lightweighting of body parts. A typical component is the shock tower, the traditional stamping and welding to die-casting integrated design, parts significantly reduced, lightweighting effect is also very obvious. In addition, four doors and two covers system using aluminum stamping and magnesium alloy die-casting integrated forming has also been applied on a large scale, with the further advancement of lightweighting demand and related materials and parts suppliers to increase production, the price bottleneck problem will also be solved.
The cover parts are the parts with high requirements for appearance, and at present they are mainly formed by steel plates. All-aluminum body design introduced 6xxx aluminum plate as a car covering parts, these products are still mainly models in use, there are aluminum natural aging and stamping rebound difficult to control and other technical reasons, there are also suppliers less high price reasons.
Second, the classification of alloy aluminum die-casting parts
The classification of alloy aluminum die-casting parts in the automobile is concentrated in two aspects, respectively, aluminum-silicon alloy and aluminum-magnesium alloy, the specific analysis is as follows.
1, aluminum - silicon system alloy
Aluminum-silicon alloy refers to the increase of silicon element in the alloy aluminum die-casting parts, to promote aluminum castings with considerable tensile strength, hardness and fluidity, the alloy is mixed with silicon material to help improve the alloy aluminum die-casting parts wear resistance, reduce the coefficient of linear expansion. The alloy aluminum die-casting parts used in the automobile, silicon content reaches 12.6% value, the alloy will show good fluidity, thermal cracking and shrinkage will also be reduced, the alloy aluminum die-casting parts have good performance. Alloy aluminum die-casting parts in the development of the automobile manufacturing industry, aluminum - silicon system alloy gradually introduced in the metal elements, the purpose is to optimize the performance of alloy aluminum die-casting parts in the automobile, specifically such as: ① copper elements in the alloy aluminum die-casting parts can enhance the overall mechanical strength, control the amount of copper elements mixed into the alloy to prevent more copper elements and aggravate the corrosion of aluminum castings; ② magnesium elements mixed into the alloy aluminum die-casting parts fundamentally improve the alloy corrosion and toughness, in accordance with the requirements of aging to achieve the role of dispersion of alloy aluminum die castings; ③ automotive aluminum castings in the joint admixture of copper and magnesium elements, optimize the performance of aluminum castings, strengthen the toughness strength, while reducing the application cost of aluminum castings.
2, aluminum - magnesium system alloy
The actual automotive aluminum castings can be directly mixed with magnesium elements. Aluminum - magnesium system alloy has the characteristics of the mechanics of the room temperature state, its manufacturing in the automobile by the wall thickness effect reduces the performance of casting, resulting in alloy aluminum castings cracking problem, so in the automobile manufacturing to control the wall thickness effect, solve the problem of aluminum - magnesium alloy cracks, focusing on the advantages of such alloys in the automobile, the strength of automotive components.