It is not unfamiliar to mention aluminum alloy wheels. When buying a car, it will be weighed and compared by consumers as a more important reference indicator for appearance and configuration. In fact, I fully agree with this approach, because the aluminum alloy wheel has the advantage that the steel wheel can't match, and it has a great influence on the future driving.
Aluminum alloy wheels have many advantages over steel wheels:
First, the heat dissipation is good: the heat transfer coefficient of aluminum alloy is three times larger than that of steel. The friction between the tire and the ground and the brake disc and the brake pad during the running of the car will generate a very high heat, which will cause the tire and the brake pad to age and accelerate the wear, and the braking performance will be abruptly attenuated due to the high temperature. There is also a risk of puncture in the tire. Aluminum alloy wheels transmit this heat to the air faster than steel wheels, increasing the safety factor.
Second, light weight: the proportion of aluminum alloy wheels is smaller than that of steel wheels, the average one is about two kilograms lighter than the same size steel wheel, and the total spare wheel can be reduced by eight kilograms; the lighter wheel can also reduce the starting and accelerating time. The resistance, the two work together to make the vehicle more fuel efficient.
Third, the precision is high: the precision of aluminum alloy wheel casting is much higher than that of steel wheel hub, and the roundness and unbalance weight are small; in addition, the aluminum alloy has small elastic modulus and better anti-vibration performance than steel wheel hub. These two can effectively reduce vehicle vibration and make driving more comfortable.
Fourth, more beautiful: aluminum alloy in high temperature liquid state fluidity and tension better than steel wheels, post-polishing and electroplating process to make it more beautiful and changeable appearance; surface anti-corrosion treatment and electrostatic powder coating It also makes it last forever.
Can the deformation of the aluminum alloy wheel be repaired?
I personally think it is ok, and now there are many mechanisms for repairing the deformation of aluminum alloy wheels. But for the sake of safety, it is still new.
These stores not only promote the deformation of the rim, but even the cracking can be repaired. As the saying goes, don't look at advertising to see the effect.
Can the actual strength of these repaired rims meet safety standards? The figure below is the criteria for BMW (BMW) to determine the deformation of the rim:
The upper limit of the 0.3mm bounce yaw set by BMW is a very strict requirement. The rims with a yaw of more than 0.3mm can only be scrapped and replaced with new ones.
Some friends may say that BMW forced the scrapping of the rims, which does not mean that the wheel has no maintenance value. Only the Germans have high wages, and the labor cost of repairing may be more expensive than buying a new rim produced in batches. Of course, this is also a very convincing reason.
Why is BMW forced to scrap the deformed rim?
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. According to the processing method, it can be divided into two types: deformed aluminum alloy and cast aluminum alloy. The deformed aluminum alloy is divided into non-heat-treated reinforced aluminum alloy and heat treatable reinforced aluminum alloy. The deformed aluminum alloy has excellent plasticity (relatively high aluminum content), and can be subjected to deep processing deformation in a hot state and a cold state. It can form a single-phase solid solution when heated, and has good plasticity and is suitable for processing. If the aluminum alloy wheel hub is made of a heat-resistant reinforced deformation-alloyed aluminum alloy, it is of course feasible to perform deformation repair in a hot or cold state, but it is unfortunate that the aluminum alloy rim is not a deformed aluminum alloy.
Since the aluminum alloy wheel has a light weight and high manufacturing precision, the deformation is small at the time of high-speed rotation, and the inertia resistance is also small. This is beneficial to improve the straight running performance of the car and reduce the rolling resistance of the tire, thereby reducing fuel consumption.