Applications of Aluminum Alloy to Commercial Vehicles

April 13, 2023
Technical Articles

A new wave of industrial transformation and technological revolution is sweeping the world. New materials and technologies in the automotive industry are widely used, and new models and new formats are emerging. To cope with this new wave, Dongfeng Company responded to the national concept of "five modernizations", namely lightweight, electrification, intelligence, networking, and sharing. Lightweight, as the main way to save energy and reduce emissions, has become the focus of body development in recent years. For the future trend of lightweight commercial vehicles, materials and processes are important ways to reduce the weight of automobiles, and the integrated application of multiple materials is the development direction of automotive materials. New materials, new processes and new technologies are the sources of power for development to meet the coordinated development of lightweight, cost and user expectations.

The application of lightweight materials in the body-in-white of commercial vehicles is explained in this article. Lightweight materials have different characteristics. The main lightweight materials for body-in-white include high-impact steel, aluminum alloy, glass fiber-reinforced plastics, and composite materials. The weight reduction effect and relative cost of several commonly used lightweight materials are shown in Table 1. According to requirements for the material of different parts for the body-in-white, develop light-weight, high-performance, and easy-to-form advanced lightweight material, and provide material research and development and technical reserves for the design and manufacture of energy-saving commercial vehicles.

Table 1 Weight reduction effect and relative cost of lightweight materials

Materials	Relative costs of materials	Relative costs of parts	Weight reduction %
Mild steel	1.0	1.0
High-impact steel	1.1	1.0	10
Aluminum alloy	4.0	2.0	40 to 50
Glass fiber reinforced plastics	3.0	0.8
Composite materials	3.0	0.8	25 to 35

2. Aluminum alloy
Aluminum alloy is widely used in body-in-white as a lightweight representative material based on the following advantages:
(1) Low density and lightweight: while the strength and rigidity can meet the requirement for safety, the use of aluminum alloy can greatly reduce the weight of the vehicle. Since the density of aluminum alloy is only one-third of that of steel, generally speaking, aluminum alloy vehicles are 30% to 50% lighter than steel vehicles.
(2) Fire resistance and corrosion resistance: aluminum alloy has excellent thermal conductivity, and it also dissipates heat better than steel. Aluminum alloy is easy to oxidize, and an oxide film is formed on the surface; aluminum alloy has better corrosion resistance than a steel body.
(3) Good impact absorption: the impact absorption capacity of aluminum is twice that of steel, and it has obvious advantages in terms of collision safety.
(4) Easy processing and manufacturability: aluminum alloy parts are suitable for various surface treatments, so it is easier to maintain. Good recyclability greatly simplifies the manufacturing process.

The technology of aluminum alloy used in auto parts and bodies has matured based on the above advantages, and can be applied to body-in-white outer coverings, such as roof panels and door outer panels. However, the application of aluminum alloys to domestic commercial vehicle cabs is still limited. The reasons are as follows:
(1) It is difficult to form mainly due to poor deep drawing performance, and the foreign manufacturing level has reached the same stamping performance as steel plate; it is widely used in foreign commercial vehicle bodies.
(2) Welding performance is poor. Since the thermal conductivity and electrical conductivity of aluminum alloy are 3 times that of steel, and the welding seam strength of aluminum is lower than that of steel; the current density required for welding aluminum alloy is about 3 times that of steel, so it is necessary to consider other ways to connect parts.
(3) The aluminum alloy cannot be restored to its original shape after being deformed by impact, and the whole part must be removed and replaced with a new one, resulting in high maintenance costs.
(4) Corrosion of steel is accelerated after contacting aluminum alloy.
(5) The cost of aluminum alloy is high.

The application of aluminum alloys in commercial vehicle body-in-white is limited due to these disadvantages. Figure 2 is the aluminum alloy toolbox door of a commercial vehicle. The toolbox door is easy to form and the inner and outer panels are connected by hemming, so it overcomes the problems of forming and welding processes; because the toolbox door is a relatively independent system, the maintenance process is easy to change independently; it overcomes the problem of difficult maintenance. Because the parts are not big, the impact on the cost is also small, and a better weight reduction effect can be achieved. The parts can be used as the main application of aluminum alloy to commercial vehicles due to the small parts, small impact on the cost and a better weight reduction effect.

Figure 2 The aluminum alloy toolbox door of a commercial vehicle

5. Conclusion
The application of lightweight materials to the structure of the body-in-white of commercial vehicles can effectively reduce the weight of the cab and achieve the effect of energy saving and consumption reduction. However, lightweight materials cannot be widely used due to reasons such as high costs and complicated processes. Therefore, it is necessary to apply lightweight materials to the body-in-white structure with the idea of using the right material in the right place. Nowadays, the automobile manufacturing industry is developing rapidly. At the same time, global environmental issues and energy shortages are becoming more and more prominent, and the lightweight development of automobile manufacturing has become one of the important topics in product research and development. How to reduce the weight of the car body as much as possible and improve the power of the car while ensuring the safety of the car is an important prerequisite for the extensive application of lightweight materials to achieve the purpose of weight reduction, and it is also an important way to achieve environmentally friendly car manufacturing. If lightweight materials are to be widely used in the manufacture of automobiles, especially commercial vehicles, in-depth research on the mechanical and thermal stability of lightweight materials is required, and further optimization of the manufacturing process is required. I believe that with people's research on lightweight materials and further emphasis on applications, the dream of a lightweight body is just around the corner.

Next: Test Results & Analysis of Properties of ADC12 Aluminum Alloys (Part one)

Previous: Effect of Rheological Die Casting on Properties of ADC12 Aluminum Alloys

Applications of Aluminum Alloy to Commercial Vehicles

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