Why aluminum is used in Transportation Industry?

2025-06-18

The widespread use of aluminum in transportation industry is closely related to its excellent physical and chemical properties, and the diversified development of aluminum alloys has further expanded its application scenarios.

1. The core reasons for the application of aluminum in transportation industry

- Significant lightweight advantages
The density of aluminum is about 2.7g/cm³, which is only about 1/3 of steel. In transportation tools, lightweighting can directly reduce energy consumption (for example, for every 100kg weight reduction of a car, the fuel consumption per 100 kilometers can be reduced by 0.3-0.6L), improve endurance (for example, weight reduction of electric vehicles can extend the range), and reduce the load on the power system.

- High specific strength (strength/weight ratio)
Pure aluminum has low strength, but high-strength aluminum alloys can be formed through alloying (such as adding copper, magnesium, zinc, etc.). The strength of some aluminum alloys (such as 7075) is even close to that of high-strength steel, meeting the load-bearing requirements of structural parts.

- Excellent corrosion resistance
A dense aluminum oxide (Al2O3) oxide film is easily formed on the surface of aluminum, which can effectively resist rain, moisture and salt spray corrosion, and is especially suitable for ships, coastal transportation vehicles and outdoor use scenarios (such as truck bodies).

- Good processing performance
Aluminum has high ductility and can be made into complex-shaped parts (such as automobile covers and aircraft skins) through extrusion, stamping, casting and other processes, and has good weldability (such as 5XXX series aluminum alloys are suitable for welded structures).

- Strong recyclability and high environmental benefits
The energy consumption of aluminum recycling is only 5% of that of original aluminum production, and the performance remains basically unchanged after recycling. After the transportation vehicle is scrapped, aluminum parts can be efficiently recycled, which meets the needs of the circular economy (such as the recycling rate of automobile aluminum wheels exceeds 90%).

- Thermal conductivity and shock absorption
Aluminum has a high thermal conductivity and can be used for heat dissipation components (such as engine cylinders and battery cooling systems); at the same time, its good shock absorption performance can reduce the vibration and noise of transportation vehicles during driving (such as high-speed rail carriage structures).

2. Specific application scenarios of aluminum in the transportation industry

(1). Automobiles and new energy vehicles
- Body parts: aluminum alloy body frame, doors, hood, trunk lid (such as Tesla Model S body aluminum alloy accounts for more than 70%), reducing weight while improving collision safety.
- Power system: engine cylinder block, cylinder head, gearbox housing (replacing cast iron, reducing engine weight), aluminum alloy battery tray (protecting batteries and dissipating heat).
- Chassis and walking system: aluminum alloy wheels (lightweight to reduce unsprung mass and improve handling), suspension system components (such as control arms).
- Others: air conditioning condenser (good thermal conductivity), body anti-collision beam (energy absorption is better than steel).

(2). Aviation and aerospace
- Aircraft structure: fuselage skin (such as Boeing 787 fuselage aluminum alloy usage is about 20%), wing frame, tail wing components (2XXX series, 7XXX series high-strength aluminum alloy).
- Landing gear and engine: landing gear hub, engine fan blades (7075 aluminum alloy), high temperature resistant aluminum alloy for engine nacelle parts.
- Spacecraft: satellite shell, rocket fuel tank (aluminum-lithium alloy, further weight reduction and high strength).

(3). Rail transit (train, subway, high-speed rail)
- Carriage body: car shell welded from aluminum alloy profiles (such as China High-speed Rail CRH series cars use 6005A aluminum alloy profiles), reducing weight while meeting fire protection standards.
- Internal structure: roof luggage rack, seat frame, floor support (corrosion resistant, easy to clean).
- Bogie and braking system: aluminum alloy brake disc, bogie frame (reduce train weight and increase running speed).

(4). Ships and marine transportation
- Hull and deck: hull of coastal ships and yachts (5XXX series aluminum alloy, resistant to seawater corrosion), such as aluminum alloy speedboats that are more than 50% lighter than steel hulls.
- Internal equipment: cabin partitions, piping systems (resistance to salt spray corrosion, reducing maintenance costs).

(5). Other means of transportation
- Motorcycles and bicycles: aluminum alloy frames and wheels (such as high-end bicycle frames mostly use 7005 aluminum alloy), lightweight to improve riding efficiency.
- Containers and logistics equipment: aluminum alloy containers (40% lighter than steel containers and rust-resistant), logistics vehicle compartment panels.

3. Commonly used aluminum alloy types and applications in the transportation industry

Aluminum alloys can be divided into the following main series according to alloying elements and properties. The characteristics of each series and their applications in the transportation field are as follows:

Aluminum and aluminum alloys have become the transportation industry's first choice for achieving lightweight, high strength, and corrosion resistance. The core material for the goal of "energy saving, high efficiency and environmental protection". From automobiles to aviation, from land to sea, the diversified series of aluminum alloys (such as 2XXX series for aviation applications and 6XXX series for rail transit applications) have further promoted the technological upgrading of transportation tools. In the future, with the development of aluminum-lithium alloys and new high-strength aluminum alloys, their application scenarios will continue to expand.

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