Did you know that reducing an electric vehicle's weight by 180 kg can boost its range by up to 17%? This isn't theory—it's an engineering fact backed by solid data.
While most automakers compete on battery capacity and charging speed, a group of engineers is quietly changing the game through a different approach—making cars lighter. And one of the most critical technologies enabling this? Aluminum forging.
Why Lightweighting Has Become Essential for EVs
In the traditional combustion engine era, weight reduction was primarily about fuel savings. According to the U.S. Department of Energy, a 10% reduction in vehicle weight can improve fuel economy by approximately 6-8%. That's a decent number, but in electric vehicles, the value of lightweighting multiplies several times over.
EVs exhibit what engineers call a "compounding effect": lighter vehicle → smaller battery needed → lighter battery makes the car even lighter → costs drop accordingly. This creates a positive feedback loop. Simply put, you're not just reducing weight—you're also cutting battery costs and charging time.
Here are the real numbers: According to a 2020 European market study, for every 100 kg of weight reduction in an EV, energy consumption drops by 0.47 to 1.17 kWh/100km, depending on vehicle type and driving patterns. For a mid-size SUV with a 60 kWh battery and 400 km original range, reducing weight by 180 kg (about 10%) can extend range from 400 km to 424-466 km—an improvement of 6-17%.
Forging vs. Casting: Why Chassis Components Demand Forged Parts
When it comes to aluminum components, many ask: Isn't casting cheaper and more geometrically flexible? Why insist on forging?
The answer lies under the microscope.
The biggest enemy of cast aluminum alloys is porosity—gas pores and shrinkage cavities. A 2022 study on the common casting alloy A356-T6 found that porosity damages fatigue performance more severely than microstructure coarsening. Cracks initiate prematurely at pore edges due to stress concentration, drastically reducing component life.
Forging is entirely different. The European Aluminum Association notes that aluminum die forging creates a "fibrous microstructure," with optimal mechanical properties—strength, ductility, toughness, and fatigue resistance—achieved along the fiber direction. Even better, this fiber orientation can be "engineered to align" with service load directions through die design and process parameters.
In plain terms: forging lets you "design" the internal structure of the metal, making it strong where it needs to be strong and tough where it needs to be tough. For chassis components under cyclic loading, this is a decisive advantage.
Here's a real data comparison:
| Material | Density | Yield Strength | Fatigue Strength | Specific Yield Strength |
|---|---|---|---|---|
| Forged Al 7075-T6 | 2.81 g/cm³ | 503 MPa | 159 MPa | ≈179 |
| Cast Al 356.0-T6 | 2.68 g/cm³ | ≥138 MPa | 60 MPa | ≈51 |
| Steel AISI 4140 | 7.85 g/cm³ | 415 MPa | — | ≈53 |
The specific yield strength (strength/density) of forged 7075-T6 aluminum is 3.4 times that of steel. This means that in "strength-limited" designs, forged parts can achieve extremely aggressive weight reductions.
How Tesla and NIO Use Forged Aluminum
Tesla's approach is pragmatic: not full aluminum adoption, but "putting the right material in the right place."
According to technical teardown reports, the Model 3's front steering knuckle uses forged aluminum alloy, while the rear knuckle uses cast aluminum. This division makes engineering sense: the front axle handles more complex steering, braking, and road load spectra with higher durability requirements, so forging reduces defect sensitivity; the rear axle, with relatively simpler loads, can use casting for greater geometric freedom and cost advantages.
NIO emphasizes the "unstrung mass reduction" narrative even more. The ET7's five-link suspension uses forged aluminum components, primarily to reduce unstrung mass. What are the benefits of lighter unstrung mass? Better vehicle attitude control—less nose lift during acceleration, less dive during braking, and faster steering response.
The new ES8 goes further, extensively using forged aluminum control arms and lightweight aluminum steering knuckles, achieving over 30% weight reduction compared to traditional cast iron parts.
Where Are the Technical Barriers for Forged Aluminum?
If forging is so good, why don't all automakers adopt it universally?
Because aluminum forging is far more difficult than you might imagine.
First, there's the "narrow temperature window." Take the commonly used 6082 alloy: forging temperature is approximately 430-500°C, but the solidus is only 575°C. The safe margin is less than 100 degrees, and you must also account for heat generated by deformation and friction. Any localized overheating causes irreversible microstructural damage.
Second, there's the "recrystallization problem." Research from Taiwan found that 6082 can form coarse recrystallized surface layers after hot deformation and heat treatment, even exhibiting mixed coarse and fine grain structures. These conditions degrade mechanical and fatigue properties. Controlling "where recrystallization occurs," "whether coarse grains appear," and "whether grain size distribution is uniform" are the most common materials science challenges in mass production.
There's also "flash line" placement. During forging, excess material is squeezed into flash, and impurity particle density is highest near the flash line. If these areas coincide with high cyclic stress locations, they become fatigue weak points. This requires coordination between die design and CAE fatigue analysis from the earliest stages.
Future Technology Breakthrough Directions
Facing these challenges, the industry is pushing forward in several directions.
Cast-forging hybrid processes combine casting's geometric freedom with forging's performance advantages. A 2023 study showed that AlSi7Mg using cast-forging achieved tensile strength improvement from 290 MPa to 311 MPa, and elongation from 11% to 13%. This provides an intermediate path that reduces die costs while maintaining performance.
Rapid heat treatment is another highlight. Traditional solution treatment and aging require long times and can easily cause grain coarsening. Research found that using salt bath or infrared rapid heating can complete solution treatment before grain coarsening occurs, achieving tensile strength exceeding 400 MPa while maintaining finer grain size. This is crucial for shortening production cycle times and improving quality consistency.
Liquid die forging (squeeze casting) sits between casting and forging, combining liquid forming's complex shaping capability with solid forging's high-pressure, high-performance characteristics, and is receiving attention as lightweighting demands increase.
Conclusion: The Next Decade of Lightweighting
The positioning of aluminum forging in the EV era is clear: not to completely replace casting, but to provide higher load-bearing capacity per unit weight and more reliable durability performance in chassis, steering, and suspension "fatigue-critical parts" through designable metal flow lines and low-defect microstructures.
For automakers and suppliers evaluating lightweighting solutions, the key question has shifted from "whether to use forged aluminum" to "how to use it smarter"—the right parts, the right alloys, the right heat treatment, integrating weight, cost, and carbon footprint into competitive metrics.
In the next decade, whoever can turn forging into a "system solution" will run faster on the EV lightweighting track.
Want to Learn More?
If you have any questions about aluminum forging technology or automotive lightweighting, feel free to contact us. We specialize in aluminum forged component development and manufacturing, with complete technical capabilities from material to finished product.