The front lower control arm connects the vehicle body to the wheels.

Core load-bearing component

Wanxiang Intelligent Manufacturing High-Strength Steel Front Lower Control Arm Assembly

Based on FB780 high-strength steel material

Tackling challenges through the integrated approach of materials, structure, and process.

Successfully developed a new-generation front lower control arm.

Compared to the traditional front lower control arm, it is 9.8% lighter.

Fatigue life increased by 38.8%

The parts replacement cycle has been extended by 25%.

Cost reduction per unit: 5.4%

Multiple models adopted by User B

Achieved a dual breakthrough in product performance and economic benefits.

Material Selection

Finding the optimal solution between “performance” and “feasibility”

Traditionally, front lower control arms have often been made from cast iron or ordinary steel, which suffer from drawbacks such as excessive weight and insufficient impact resistance. To break through the performance limitations of conventional control arms, material selection is the primary starting point.

The photo shows engineers adjusting parameters on the production line.

High-strength steel materials boast higher yield strength and tensile properties, making them particularly well-suited for safety-critical components such as automotive control arms that are subjected to complex, alternating loads. However, the forming process for these materials also requires significantly greater forces, thereby increasing the difficulty of application geometrically. To address this challenge, engineers combined user design requirements with the material properties of high-strength steel, conducted multiple rounds of sheet-metal forming analysis and verification, repeatedly fine-tuned model parameters, and simulated various extreme operating conditions. Ultimately, they identified FB780 high-strength steel as the optimal solution.

Structural optimization

The ultimate pursuit of balancing “high strength” with “lightweight.”

“Structural design isn’t just about drawing blueprints—it’s about striking a balance among ‘is the strength sufficient, can we reduce the weight, and will the cost exceed the budget?’ Every single modification must be backed by data and must also stand up to real-world testing,” summarized the engineer involved in the development. To fully unlock the performance of FB780 high-strength steel, the project team leveraged CAE fatigue analysis tools as a foundation and embarked on a cyclical process of “simulation—testing—optimization.”

The photo shows engineers tackling the challenging CAE fatigue analysis.

The risk of failure often lurks in the details—for instance, at the overlap between the casing and the main body. If the weld design is not optimized, cracks are likely to develop over time under sustained stress. Another example is the thickness of the stiffening ribs: too thick, and they’ll add unnecessary weight; too thin, and they’ll fail to provide adequate reinforcement... “We just keep testing and tweaking—making minor adjustments, conducting tests, and starting over if the data doesn’t meet our standards—until every single parameter falls within the target range,” said the engineer, his words brimming with meticulous dedication. Based on feedback from actual tests, they’ve continuously fine-tuned the thickness of the stiffening ribs, adjusted the angles of the flanges, and optimized local structural designs to redistribute stress effectively. As a result, they’ve reduced damage to critical welds to just 0.566 (the target is less than 1), significantly enhancing the product’s overall strength and durability.

Process problem-solving

Turn “theoretically feasible” into “mass-production reliable.”

Although the FB780 high-strength steel boasts high tensile strength and excellent yield performance, its elongation rate tends to decrease accordingly. This characteristic turns sheet metal forming processes—such as bending, stamping, and deep drawing—into a challenging issue in actual production.

The photo shows engineers collecting data in the workshop.

During the project’s advancement, engineers spent every day immersed in the production workshop, standing by the machines and meticulously recording every detail of the material-forming process. “There are no shortcuts to overcoming technical challenges—only by observing more, experimenting more, and taking detailed notes can we systematically address each issue in the workshop and turn blueprints into qualified parts.” They carefully observed how different bevel angles affected mold formation, tested the impact of the rounded corners at the bottom of the molds on machining, and adjusted the pressure parameters and feed rates in the drawing process. After each adjustment, they conducted thorough parameter inspections on the formed parts, collected data, and summarized patterns. Through countless rounds of trial and error in the manufacturing process, they not only managed to keep the forming thinning rate—a measure of how much the material thickness decreases during metal sheet forming due to plastic deformation—at a stable 6%, surpassing industry standards, but also boosted material utilization by 6.2% by optimizing the mold layout.

Currently, the high-strength steel front lower control arm.
All bench and road tests have been passed.
Enter the stage of stable mass production.
Successful development of a high-strength steel front lower control arm
For the subsequent upgrade of other chassis structural components.
Provided reusable and implementable practical experience.
Inspire the engineers
Continuously explore the application potential of high-strength steel.
Deepen research on the compatibility of materials, structures, and processes.
Promote the company's products
Continuously moving toward high strength, lightweight design, and long service life.