Popular Science of Metal Materials in Automobile Lightweighting-Aluminum Alloy
In the development of the automotive industry, lightweighting has consistently been an important and highly regarded direction. This trend holds significant implications for new energy vehicles. It is not only key to improving driving range but also central to enhancing fuel economy, reducing emissions, and optimizing vehicle performance.
In the automotive field, aluminum alloy is a critical material for achieving vehicle lightweighting. With its excellent properties—including high strength-to-weight ratio, strong corrosion resistance, and recyclability—aluminum alloy is increasingly replacing traditional steel in automobile body structures, securing a more prominent role in the industry.
I. Characteristics of Aluminum Materials
(1) Low Density
The density of aluminum alloy is typically around 2.7 g/cm³, approximately one-third that of steel, copper, or brass. This means aluminum alloy is lighter in weight for the same volume. In automotive manufacturing, an aluminum alloy body can reduce the vehicle's overall weight, helping to lower fuel consumption and improve handling performance.
(2) High Strength
After proper heat treatment, aluminum alloy can achieve higher strength. Its tensile strength can reach 200–600 MPa, and some high-strength aluminum alloys can even match the strength of medium-carbon steel. This allows aluminum alloy to withstand greater loads.
(3) Good Corrosion Resistance
A dense aluminum oxide film naturally forms on the surface of aluminum alloy, effectively preventing the aluminum matrix from further contact with the external environment and providing excellent protection. Under typical environmental conditions, such as atmospheric or freshwater environments, aluminum alloy remains stable for extended periods and resists corrosion. However, in certain aggressive chemical environments (such as strong acid or strong alkali conditions), the corrosion resistance of aluminum alloy may be compromised.
(4) Good Electrical and Thermal Conductivity
Aluminum alloy is an excellent conductor of heat and electricity, with electrical conductivity approximately 60–70% that of copper. In the power industry, aluminum alloy is widely used for manufacturing wires and cables. It also exhibits strong thermal conductivity, making it suitable for heat exchange equipment such as radiators. For instance, the aluminum alloy heat sink in computers efficiently conducts and dissipates heat generated by the chip, ensuring optimal performance.
II. Aluminum Alloys in the Automotive Industry
- Body and Frame
Aluminum alloys can be used to manufacture body frames, such as the A-pillars, B-pillars, and roof rails of automobiles. These components utilize a combination of 1500MPa hot-formed steel and aluminum alloy to ensure structural integrity while achieving weight reduction.
- Engine Parts
Aluminum engine blocks offer excellent thermal conductivity, enabling efficient dissipation of heat generated during engine operation. This helps maintain optimal operating temperatures while enhancing reliability and durability. Additionally, their lightweight properties reduce overall engine weight, improving vehicle acceleration performance. Aluminum pistons minimize energy loss during high-speed reciprocating motion, increasing fuel efficiency. They also withstand high-temperature and high-pressure environments, further improving the engine's mechanical efficiency.
- Chassis and Suspension System
Aluminum alloys are also widely used in chassis and suspension systems. Forged aluminum alloys can be utilized to manufacture lightweight and durable suspension components, such as control arms, steering knuckles, and suspension brackets. These parts reduce weight while maintaining sufficient strength and rigidity, enhancing the vehicle's handling performance.
- Radiator and Heat Exchanger
Because aluminum alloy has excellent thermal conductivity, it is an ideal material for manufacturing radiators and heat exchangers. It effectively dissipates heat generated by components such as engines, ensuring thermal balance in vehicles during operation.
III. Joining Technology of Aluminum Alloy Materials in Automobiles
Heron Intelligent Equipment is an innovative mechanical connection technology. Special rivets are automatically fed into the upper rivet head using specialized riveting equipment. During the stamping process, the rivets are punched and discharged by the connected parent material, and then the material surrounding the rivet is compressed by the lower die to create a reliable connection.
This tool can rivet a variety of materials, including high-strength aluminum alloys, and is capable of performing FSPR to accommodate connections between materials of varying strengths and thicknesses in the automotive industry—such as hot-forming steel, aluminum-magnesium alloys, carbon fiber, and PP materials. It also supports multi-layer riveting, with a maximum total thickness of 9.1mm.
Key process advantages include:
- No pre-punching required; punching and riveting are completed in a single step.
- High automation level with a fast riveting cycle.
- Strong material adaptability, including compatibility with a wide range of material elongation rates.
The connection quality is reliable, with strong and stable shear and tensile resistance. The riveting appearance is consistent and offers excellent rust resistance. The process is stable and easy to monitor. FSPR is a material compression molding method. The material remains intact after riveting, allowing for visual inspection to determine if the rivet is defective or if the connection meets quality standards.
This process features an upgraded technical configuration compared to traditional riveting technology and can be applied to connecting structural components such as aluminum alloy body frames. While maintaining connection strength, it reduces body weight, improves vehicle handling performance and fuel efficiency, and better meets the automotive industry's stringent requirements for safety factors and quality stability.