The automotive industry uses magnesium castings on a large scale. The core driving force comes from the multiple superposition of lightweight demand, performance advantages and policy orientation. The specific reasons are as follows:
1. Lightweight and weight reduction, improve fuel efficiency and endurance
Density advantage: The density of magnesium alloy is only about 1.8g/cm³, which is 2/3 of aluminum alloy (2.7g/cm³) and 1/4 of steel (7.8g/cm³). The weight is significantly reduced under the same volume.
Case: If the automobile wheel hub is replaced from aluminum alloy to magnesium alloy, the weight of a single wheel hub can be reduced by about 30%~50%.
Fuel economy: For every 100kg reduction in vehicle weight, fuel consumption per 100 kilometers can be reduced by 0.3~0.5L; for new energy vehicles, a 10% weight reduction can increase the cruising range by 5%~8%.
Policy pressure: Many countries around the world are implementing strict carbon emission regulations (such as the EU's average carbon emission target of 95g CO₂/km for new cars in 2025), and lightweighting has become a key path for automakers to comply with regulations.
2. Excellent comprehensive performance to meet the needs of complex working conditions
High specific strength: The strength of magnesium alloy is close to that of aluminum alloy, but it is lighter and suitable for manufacturing load-bearing structural parts (such as chassis parts).
Shock absorption and noise reduction: The damping performance of magnesium alloy is better than that of aluminum alloy, which can reduce vibration and noise during vehicle driving (such as instrument panel bracket).
Good heat dissipation: The thermal conductivity of magnesium alloy is about 150~180W/(m・K), which is suitable for high heat dissipation demand parts around the engine (such as cylinder head cover).
Electromagnetic shielding: Magnesium alloy has a good shielding effect on electromagnetic waves and is suitable for vehicle-mounted electronic equipment housings.
3. Mature process, suitable for large-scale production
High die-casting efficiency: magnesium alloy has good fluidity in molten state, and can realize one-time molding of complex structural parts through high-pressure die-casting process, with short production cycle (single-piece production time can be controlled within 30 seconds to 2 minutes).
Design flexibility: The mold can support thin-walling (minimum wall thickness 0.5mm), integrated molding (such as integrating multiple functional modules), reducing the number of parts and assembly costs.
4. Environmental protection and recycling advantages
Recyclable: The recovery rate of magnesium alloy exceeds 90%, and waste castings can be directly used for reproduction after smelting, which meets the sustainable development requirements of the automotive industry.
Low-energy production: Compared with aluminum alloy, the melting temperature of magnesium alloy is lower (about 650℃ vs. aluminum alloy 700~750℃), and energy consumption is reduced by about 15%~20%.
What are the typical application parts of magnesium castings in the automotive industry?
The application of magnesium castings in the automotive field has expanded from non-load-bearing parts to key structural components. The following are the core application scenarios:
1. Power system
Gearbox housing: replace aluminum alloy or cast iron, reduce weight by about 30%, and improve heat dissipation efficiency (such as the case of a magnesium alloy gearbox housing of a German car company).
Engine cylinder head cover: covers the top of the engine, reduces vibration and noise, and is resistant to oil and high temperature (working temperature ≤150℃).
Clutch housing: used for manual transmissions, requiring high strength and dimensional stability.
2. Chassis and suspension system
Steering knuckle: connects the wheel and the suspension system, and needs to withstand complex loads. The magnesium alloy steering knuckle can reduce weight by more than 50% compared with steel parts (such as the case of a US electric car).
Suspension bracket: supports shock absorbers, springs and other components to improve handling stability.
Wheel: High-end models (such as sports cars and luxury SUVs) use magnesium alloy wheels, which are both lightweight and high rigidity. Some racing wheels even use magnesium-lithium alloy (density as low as 1.2g/cm³).
3. Body and interior system
Instrument panel frame: As the core support of the interior, it requires low deformation and easy assembly. The magnesium alloy frame can integrate functional modules such as air-conditioning outlets and airbag brackets.
Seat frame: The seat frame and adjustment mechanism reduce weight while improving collision safety (such as the magnesium alloy seat frame case of a Japanese car company).
Steering wheel frame: Replace aluminum alloy, reduce weight by about 20%, and improve texture through surface treatment (such as electroplating).
4. Other key components
Battery shell: The outer shell of the battery pack of new energy vehicles requires lightweight, impact resistance and electromagnetic shielding (such as the magnesium alloy battery shell of a domestic electric vehicle, which is 40% lighter than aluminum alloy).
Motor end cover: Used to drive the motor, it needs to take into account both heat dissipation and structural strength.
Pedal bracket: The supporting structure of the brake and accelerator pedals requires high rigidity and safety.
Future trends: from "partial substitution" to "system integration"
With the breakthroughs in the research and development of magnesium alloy materials (such as high-strength magnesium-rare earth alloys) and process innovations (such as semi-solid die casting and vacuum die casting), the application of magnesium castings in the automotive field will expand to high-stress components (such as subframes, chassis beams) and large integrated structural parts. For example, an international automaker has tried to use magnesium alloys to manufacture vehicle frames, which reduces weight by more than 60% compared to traditional steel frames.
Under the wave of lightweighting, magnesium castings are becoming one of the core materials for the "low carbonization" and "electrification" transformation of the automotive industry.
The automotive industry uses magnesium castings on a large scale. The core driving force comes from the multiple superposition of lightweight demand, performance advantages and policy orientation. The specific reasons are as follows:
1. Lightweight and weight reduction, improve fuel efficiency and endurance
Density advantage: The density of magnesium alloy is only about 1.8g/cm³, which is 2/3 of aluminum alloy (2.7g/cm³) and 1/4 of steel (7.8g/cm³). The weight is significantly reduced under the same volume.
Case: If the automobile wheel hub is replaced from aluminum alloy to magnesium alloy, the weight of a single wheel hub can be reduced by about 30%~50%.
Fuel economy: For every 100kg reduction in vehicle weight, fuel consumption per 100 kilometers can be reduced by 0.3~0.5L; for new energy vehicles, a 10% weight reduction can increase the cruising range by 5%~8%.
Policy pressure: Many countries around the world are implementing strict carbon emission regulations (such as the EU's average carbon emission target of 95g CO₂/km for new cars in 2025), and lightweighting has become a key path for automakers to comply with regulations.
2. Excellent comprehensive performance to meet the needs of complex working conditions
High specific strength: The strength of magnesium alloy is close to that of aluminum alloy, but it is lighter and suitable for manufacturing load-bearing structural parts (such as chassis parts).
Shock absorption and noise reduction: The damping performance of magnesium alloy is better than that of aluminum alloy, which can reduce vibration and noise during vehicle driving (such as instrument panel bracket).
Good heat dissipation: The thermal conductivity of magnesium alloy is about 150~180W/(m・K), which is suitable for high heat dissipation demand parts around the engine (such as cylinder head cover).
Electromagnetic shielding: Magnesium alloy has a good shielding effect on electromagnetic waves and is suitable for vehicle-mounted electronic equipment housings.
3. Mature process, suitable for large-scale production
High die-casting efficiency: magnesium alloy has good fluidity in molten state, and can realize one-time molding of complex structural parts through high-pressure die-casting process, with short production cycle (single-piece production time can be controlled within 30 seconds to 2 minutes).
Design flexibility: The mold can support thin-walling (minimum wall thickness 0.5mm), integrated molding (such as integrating multiple functional modules), reducing the number of parts and assembly costs.
4. Environmental protection and recycling advantages
Recyclable: The recovery rate of magnesium alloy exceeds 90%, and waste castings can be directly used for reproduction after smelting, which meets the sustainable development requirements of the automotive industry.
Low-energy production: Compared with aluminum alloy, the melting temperature of magnesium alloy is lower (about 650℃ vs. aluminum alloy 700~750℃), and energy consumption is reduced by about 15%~20%.
What are the typical application parts of magnesium castings in the automotive industry?
The application of magnesium castings in the automotive field has expanded from non-load-bearing parts to key structural components. The following are the core application scenarios:
1. Power system
Gearbox housing: replace aluminum alloy or cast iron, reduce weight by about 30%, and improve heat dissipation efficiency (such as the case of a magnesium alloy gearbox housing of a German car company).
Engine cylinder head cover: covers the top of the engine, reduces vibration and noise, and is resistant to oil and high temperature (working temperature ≤150℃).
Clutch housing: used for manual transmissions, requiring high strength and dimensional stability.
2. Chassis and suspension system
Steering knuckle: connects the wheel and the suspension system, and needs to withstand complex loads. The magnesium alloy steering knuckle can reduce weight by more than 50% compared with steel parts (such as the case of a US electric car).
Suspension bracket: supports shock absorbers, springs and other components to improve handling stability.
Wheel: High-end models (such as sports cars and luxury SUVs) use magnesium alloy wheels, which are both lightweight and high rigidity. Some racing wheels even use magnesium-lithium alloy (density as low as 1.2g/cm³).
3. Body and interior system
Instrument panel frame: As the core support of the interior, it requires low deformation and easy assembly. The magnesium alloy frame can integrate functional modules such as air-conditioning outlets and airbag brackets.
Seat frame: The seat frame and adjustment mechanism reduce weight while improving collision safety (such as the magnesium alloy seat frame case of a Japanese car company).
Steering wheel frame: Replace aluminum alloy, reduce weight by about 20%, and improve texture through surface treatment (such as electroplating).
4. Other key components
Battery shell: The outer shell of the battery pack of new energy vehicles requires lightweight, impact resistance and electromagnetic shielding (such as the magnesium alloy battery shell of a domestic electric vehicle, which is 40% lighter than aluminum alloy).
Motor end cover: Used to drive the motor, it needs to take into account both heat dissipation and structural strength.
Pedal bracket: The supporting structure of the brake and accelerator pedals requires high rigidity and safety.
Future trends: from "partial substitution" to "system integration"
With the breakthroughs in the research and development of magnesium alloy materials (such as high-strength magnesium-rare earth alloys) and process innovations (such as semi-solid die casting and vacuum die casting), the application of magnesium castings in the automotive field will expand to high-stress components (such as subframes, chassis beams) and large integrated structural parts. For example, an international automaker has tried to use magnesium alloys to manufacture vehicle frames, which reduces weight by more than 60% compared to traditional steel frames.
Under the wave of lightweighting, magnesium castings are becoming one of the core materials for the "low carbonization" and "electrification" transformation of the automotive industry.
