The problem of raw materials: the mineral fiber slag ball in the brake pad will scratch the brake disc, and the slag ball in the mineral fiber is more prone to noise.

The material that is easy to scratch the disc in the raw material is artificial graphite. The artificial graphite itself is very soft, and the hardness of the impurity silicon carbide inside is close to diamond, which is enough to scratch the brake disc. For the artificial graphite used in brake pads, most small factories use recycled waste graphite (juedui does not use recycled graphite in large-brand products). Some industries have no effect on the silicon carbide contained in graphite, but it is used in brake pads. Silicon carbide becomes a very harmful substance

If there is a problem with the raw material of the brake pad, there should be a problem in the same batch, and the area may be relatively wide. In this situation, the brake pads must be replaced in time. If the brake disc is seriously damaged, the brake disc must be replaced.

This situation generally occurs when the four friction surfaces of the two symmetrical brake discs are gnawing grooves at the same time, and the position of the grooves is irregular, which may be high or low, or all grooves.

The brake pad attachment will also mark the brake pad out of the groove. Some brake pads have alarm pads (the alarm pads are generally made of stainless steel). When the brake pads are worn to the position of the alarm pads, the alarm pads will rub against the brake discs during braking and emit a harsh scream to remind the owner to change the brake pads Up. If the car owner does not care about the noise and allows the alarm and brake pads to wear, the brake disc will be scratched. This kind of pit usually only has one groove. If it is not serious, just change the brake pad. When this happens, the position of the groove in the brake disc is generally fixed, that is, the position in contact with the alarm pad.

Installation problems caused the brake disc to be gnawed. If the brake pad is installed unevenly, one end or all of it will be in contact with the brake pad for a long time, which will cause the brake disc and the brake pad to rub at high temperature for a long time. In this case, the brake disc is prone to be gnawed grooves, and there will be many grooves. This situation is likely to occur on the rear brake. When someone is driving, the handbrake is not put down or the handbrake is not put to the end, causing the brake pads to wear out for a long time, which is easy to cause this reason. It can be seen from the brake disc that the disc has changed color under long-term high temperature, and the brake disc must be replaced if it takes a long time. If the brake pads are not installed flat, there will be gnawing grooves on the disc surface. And how wide the contact area between the brake pad and the brake disc is, the position of the groove is too wide. Under such circumstances, you should not rush to replace the new brake pads and brake discs. It is possible that the disc will continue to be damaged. You should check the brake calipers carefully.

Why do the brake pads have grooves on the disc, starting from the structure of the brake pads and the composition of raw materials:

The main body of the brake pad is generally divided into two parts: the friction layer and the steel back. The main difference between the quality of the brake pad is the friction layer. The friction layer is a composite material, which is a mixture of organic fibers, inorganic fibers, mineral fillers, and phenolic resins. Composition, after high temperature and high pressure, hot press molding. Nowadays, many brake pads divide the friction layer into two layers, the bottom layer and the surface layer. The bottom layer is between the steel back and the surface layer. During the use of the brake pad, the surface layer will be worn away first. It will wear to the bottom material and then to the steel back. Generally, the brake pads should be replaced before the surface material wears out.

The brake pad itself caused the brake disc to be scratched. The surface material of the brake pad contains mineral fiber, which is formed by spinning various minerals after melting at high temperature. However, while the ore spinning process produces fibers, some of them cannot be sprayed into fibrous shape, and some form small balls (called "slag balls"). The hardness of these slag balls is much higher than that of fibrous ore. It will cause damage to the brake disc. After the mineral fiber is produced, the content of the slag ball will be as high as 40%~50%, and the enterprises of the regular manufacturers will screen. The purity of mineral fiber will be increased to about 95%~98.5%. But it still contains 1.5%~5% of slag balls (the current process cannot remove all the slag balls). Generally, the mineral fiber used in the disc fabric layer is of this type. It will inevitably contain a small amount of slag balls. Will cause damage to the brake disc. If there are too many slag balls in the fabric layer of the brake pads, the brake disc will be marked out. In serious cases, the brake pads and the brake disc need to be replaced together.

The brake disc is scratched due to human factors, and the friction layer is divided into a fabric layer and a bottom material layer. When braking, the fabric layer will be worn first, and then the bottom layer. The role of the bottom material layer is different from that of the fabric layer. The bottom material layer generally plays a role in improving the bonding strength and heat insulation. Because the focus is not on friction performance when designing the formula, the materials and fabric layers used are different. The mineral fiber content used in the fabric layer is 95%~98.5%. In the bottom material layer, mineral fibers with a high content of slag balls can be used (inexpensive). The content of slag balls may be 10% or 20%. Some manufacturers Strength, reduce cost, will use glass fiber. Enterprises with high quality requirements will add aramid fiber to the bottom layer to increase strength. The thickness of the brake pads needs to be checked regularly to see if the fabric layer has been worn out. After the fabric layer is polished, the next layer that rubs against the brake disc is the bottom layer. The main function of the bottom layer is not friction. If the brake pads are not replaced, it may cause grooves in the brake discs over time. (Nowadays, many brake pads have an alarm line. When they reach the alarm line, you will hear a noticeable noise. At this time, you need to change the brake pads. When listening to the scream, the disc has been damaged.)

In fact, the hard substance in the brake pads is not a kind of slag ball in the fiber. The glass fiber will also form glass beads under the high temperature generated during braking. The hardness is also very high. Ceramic fiber also has slag ball, many natural There may also be impurities in mineral fillers. Therefore, the regular manufacturers of brake pads will choose raw materials that contain little or no such hard substances when selecting materials. Like glass fiber, it is no longer used in discs. But like mineral fiber, as one of the main materials of brake pads, there is no better material to replace it.