Why is BMW forced to scrap deformed rims?
Because people have a hundred years of experience, while respecting science. Let's start with the classification of aluminum alloys. The concept of aluminum alloy is too broad, and can be divided into two types: wrought aluminum alloy and cast aluminum alloy according to the processing method. The wrought aluminum alloy can be divided into non heat treatment strengthening type aluminum alloy and heat treatment strengthening type aluminum alloy. Wrought aluminum alloy has excellent plasticity (relatively high aluminum content), and can be processed in hot and cold state. When heating, the single phase solid solution can be formed, which has good plasticity and is suitable for processing and forming. If aluminum alloy wheel is made of heat treated wrought aluminum alloy, it is feasible to repair it in hot or cold state. Unfortunately, aluminum alloy rim is not made of wrought aluminum alloy.
Because the aluminum alloy wheel has light weight and high manufacturing accuracy, it has small deformation and low inertia resistance when rotating at high speed. This is beneficial to improve the straight running performance of automobiles, reduce the rolling resistance of tires, and thus reduce the fuel consumption.