“Exploring car subframes”

In recent years, the automotive industry has continued to pursue innovation, and one of the lesser-known but crucial components is the subframe. This component plays a key role in the car’s suspension system, however, its importance does not seem to be widely recognized and paid attention to. So today, let’s take a brief look at this much-overlooked component of your car: the subframe.

In short, the subframe is an important structural safety component. It connects and fixes assembly parts such as suspension systems, steering systems, engines or motors, and has extremely high requirements on its strength, stiffness and modal performance. The classification of subframes mainly includes Yuanbao beam, H type and full frame type. Its function is not only to solve the balance problem between vehicle comfort and handling performance, but also to improve the performance of both, and significantly improve the vehicle’s riding comfort and handling performance.

However, a bulky subframe adds weight to the vehicle. In order to balance this feature, the aluminum alloy subframe has become a choice with obvious advantages. Compared with traditional steel subframes, aluminum alloy subframes can achieve a weight reduction of more than 30%, significantly improving lightweight performance.
Currently, with the development trend of lightweight electric vehicles and integration of castings, many automobile manufacturing companies have begun to use aluminum alloy integral low-pressure casting as the manufacturing material for the subframe of new energy electric vehicles. The integrated cast subframe has a simpler structure. The reduction of its own mass not only enhances the load-bearing performance of the entire vehicle, but is also of great significance in improving the vehicle’s handling stability.

As a chassis component, the subframe has extremely high requirements for safety and product consistency. At present, the mainstream manufacturing processes include high-pressure casting, low-pressure casting, squeeze casting and gravity casting. The high-pressure casting process solidifies and crystallizes the liquid aluminum alloy through high-pressure and high-speed punching. It has a high surface finish, excellent strength and hardness, but has a low elongation and cannot be heat treated. Although low-pressure casting is more expensive, it has better machinery. performance and safety, with a higher degree of freedom in design, making it easier to achieve hollow structures and low defects.
In squeeze casting, liquid metal is injected into an open mold to form a preliminary shape, and then high pressure is applied to complete the blank production. Its mechanical properties and dimensional accuracy are very high, and it can be heat treated later; gravity casting is injected into the mold under the action of gravity. The crystal structure is not dense enough, but the mechanical properties can be enhanced through post-heat treatment.

At present, the casting process of aluminum alloy subframes shows a trend of parallel high and low pressure. It is expected that the simple-structure subframes of light passenger cars are more likely to use high-pressure casting processes, while the complex-structure subframes of heavier models, such as 7-seat SUVs, are more likely to use low-pressure casting processes. This is mainly because low-pressure casting can use tube beam structures, while high-pressure casting cannot use sand cores, so it is difficult to design hollow structures. U-shaped structures and reinforced rib structures can only be used, or pipe sleeves can be added to certain parts to form cavities. structure. Therefore, high-pressure aluminum alloy subframe and low-pressure aluminum alloy subframe technology have become mainstream trends.

Zhengheng Dynamics has accumulated rich development experience in the field of automotive parts and components, and has production capabilities for high-pressure, low-pressure and gravity casting. We provide one-stop solutions from product design, mold making, casting to machining, and can provide customers with the best solutions based on customer needs, product performance, cost and other factors.