KR20100098816A - Vehicle brake disc and method for manufacturing the same - Google Patents

Abstract

PURPOSE: An automotive brake disk and a manufacturing method thereof is provided to supply a stable drive power after long driving by improving durability and thermostatic property and to reduce the entire weight of a brake. CONSTITUTION: An automotive brake disk comprises aluminum 20~30 weight%, copper 0.2~0.35 weight%, chrome 0.15~0.30 weight%, carbon 3.6~3.8 weight%, manganese 1.4~1.6 weight%, bandium 0.4~0.8 weight%, magnesium 3.0~6.0 weight%, nickel 1.0~6.0 weight%, grapheme 10~20 weight% and the rest of impurity. A vehicle brake disk manufacturing method comprises next steps. Alloy power is mixed. The mixed alloy power is thermoformed.

Description

VEHICLE BRAKE DISC AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to a vehicle brake disc having excellent durability and heat dissipation and a method of manufacturing the same.

The vehicle brake is a means for braking the vehicle by converting kinetic energy of the moving vehicle into thermal energy, and chemical and mechanical wear processes are generated on the surface of the brake disc during the braking operation.

Such brake discs must have a constant friction coefficient at which the vehicle can be braked, the value must remain constant even with the change of friction conditions, and the friction coefficient should not change over time, and the wear rate of the disc will be It should not be large.

The increase in the disc thickness variation (DVT) of the disc causes a judder, which is a phenomenon in which the vehicle body vibrates during braking. Therefore, the increase in the DVT should be as small as possible. The disk should be able to maintain a constant friction performance without being affected by external environmental changes.

On the other hand, in order to improve the driving performance or fuel economy of the vehicle, weight reduction is required. In response to such a demand for weight reduction, most of vehicle parts have been made with aluminum, but aluminum has not been realized for brake discs. When aluminum is used, not only the disk is worn out but also the sticking phenomenon is increased due to the high temperature, and aluminum is deposited on the surface, resulting in a decrease in the friction coefficient and a sharp drop in the friction characteristics. This is because the mechanical strength at high temperatures during braking was not sufficient.

Conventionally, the conventional brake disc is made of cast iron, but when replacing it with an aluminum composite material to reduce the weight of the vehicle and improve the brake performance, the weight reduction rate is expected to be 50% or more. The impact or ripple effect will be even greater.

In addition, when the disk is lightened as an unsprung weight among the chassis parts, the disk can achieve the effects of improved handling performance and driving comfort, and improves overall brake performance such as stabilizing friction coefficient and improving NVH. Therefore, it is time to focus on the weight reduction method along with wear resistance, corrosion resistance, hit crack, and the like of the brake disc.

The present invention has been proposed to solve the problems described above, and has an object to provide a brake disc for a vehicle and a method of manufacturing the same, which are excellent in heat dissipation and can provide a stable braking force even after a long run.

Vehicle brake disk according to the present invention for achieving the above object, by weight, carbon (C) 3.6-3.8%, aluminum (Al) 20-30%, copper (Cu) 0.2-0.35%, chromium (Cr) 0.15 ~ 0.30%, Manganese (Mn) 1.4 ~ 1.6%, Vanadium (V) 0.4 ~ 0.8%, Magnesium (Mg) 3.0 ~ 6.0%, Nickel (Ni) 1.0 ~ 6.0%, Graphene 10 ~ 20% , Remaining iron and other unavoidable impurities.

Preferably, the graphene is preferably attached or fixed to a thickness of 1 ~ 95 micrometers (μm) between the porous base material components.

On the other hand, the vehicle brake disk manufacturing method according to the invention, the process of mixing the alloy powder; And thermoforming the mixed alloy powder at a temperature of 140 to 150 ° C. and a pressure of 100 to 160 Kg / cm 2, wherein the alloy powder is, by weight, 3.6 to 3.8% of carbon (C). Al) 20 ~ 30%, Copper (Cu) 0.2 ~ 0.35%, Chromium (Cr) 0.15 ~ 0.30%, Manganese (Mn) 1.4 ~ 1.6%, Vanadium (V) 0.4 ~ 0.8%, Magnesium (Mg) 3.0 ~ 6.0 %, Nickel (Ni) 1.0-6.0%, graphene (10-20%), the remaining iron and other unavoidable impurities.

In addition, preferably, the thermoformed molded product is heat-treated at 130 ~ 160 ℃.

Also, preferably, the graphene is added to adhere or adhere to a thickness of 1 to 95 micrometers (μm) between the porous base material components.

According to the present invention as described above, it is possible to reduce the weight and wear resistance of the brake disc, and can provide excellent effects in terms of DTV and heat dissipation during the braking operation.

In addition, it is possible to prevent the brake disc from sticking during braking and to provide a stable braking force even after a long run.

First, look at the reason for limiting the composition of the brake disk according to the present invention.

Ⅰ) 20 ~ 30% by weight of aluminum (Al)

When aluminum is less than 20% by weight, sufficient heat dissipation of the brake disc is not obtained, and when aluminum exceeds 30% by weight, the wear resistance is inferior. Therefore, the content thereof is preferably limited to 20 to 30% by weight.

Ii) 0.2 to 0.35% by weight of copper (Cu)

If the content of copper is outside the range 0.2 to 0.35% by weight, the ferrite (ferrite) is present in the substrate, it is easy to produce a local wear, it is preferably limited to 0.2 to 0.35% by weight.

크롬) 0.15 ~ 0.30% by weight of chromium (Cr)

Chromium is a strong graphite inhibitor and hinders the growth of graphite by the formation of complex carbides in cast iron with 0.3% by weight of reddebutite. Therefore, the content of chromium may be controlled to be somewhat low, but if it is too low, the content of pure iron increases, so it is preferable to manage at 0.15% by weight or more of the residual amount from raw materials such as scrap scrap.

Iii) 3.6 ~ 3.8% by weight of carbon (C)

When the carbon content is lower than 3.6% by weight, D-type (the type adopted in ASTM is divided into five types of size A, E, and shape of the graphite) is likely to occur, and higher than 3.8% by weight. In this case, since the generation of Kishy type graphite easily occurs under hyper-Eutectic conditions, it is preferably limited to 3.6 to 3.8% by weight.

Manganese (Mn) 1.4-1.6 wt%

Manganese is a pearlite-promoting element of the matrix structure, which enhances the matrix structure and contributes to the improvement of wear resistance, and in order to exhibit the performance of the brake disc according to the present invention, the content is preferably limited to 1.4 to 1.6% by weight. If it is less than 1.4% by weight, the effect of improving strength is insufficient. If it exceeds 1.6% by weight, chills tend to occur in relation to other known reinforcing elements, and the material becomes soft.

Vanadium (V) 0.4-0.8 wt%

Vanadium is added to improve the wear resistance, but if the content is less than 0.4% by weight, it is insufficient to effectively exhibit the wear resistance, and if it exceeds 0.8% by weight, the effect exerted depending on the excess amount does not increase proportionally. It is limited to 0.4 to 0.8% by weight.

Ⅶ) Magnesium (Mg) 3.0 ~ 6.0 wt%

Magnesium improves the room temperature strength and the high temperature strength with respect to the mechanical strength by solid solution to aluminum. When the magnesium content is less than 3.0% by weight, the effect of strength improvement is not sufficient. Since there exists a disadvantage in inferior moldability, etc., the content is limited to 3.0 to 6.0 weight%.

Ⅷ) Nickel (Ni) 1.0 ~ 6.0 wt%

Nickel is an element that creates or precipitates as an intermetallic compound and improves the high temperature strength of the material. When nickel content is less than 1.0% by weight, nickel has no effect of improving the high temperature strength. Since it is saturated without rising, its content is limited to 1.0 to 6.0% by weight.

~) 10 ~ 20 wt% graphene

If the graphene is less than 10% by weight, the effect of improving strength is insignificant, and if the amount is greater than 20% by weight, the effect is not increased in proportion to the excess, so that the content is limited to 10 to 20% by weight. Such graphene is excellent in thermal conductivity to improve the heat dissipation of the disk.

The graphene consists of a two-dimensional layer of carbon atoms with a thickness of one atom, and the electrons in the graphene move about 1 million meters per second and behave like relativistic particles without a static mass. In addition, it acts as a friction and wear control material to delay the wear rate of other additives.

Since the graphene particles are considerably smaller than the base material, that is, other materials other than the graphene, the friction deformation material of the graphene particle size can be evenly distributed evenly throughout the base material gap or gap of the porous material. After histological examination, it was shown that graphene is preferably added in a thickness of 1 to 95 micrometers (µm) between the components constituting the porous base material.

Next, the manufacture of the brake disc according to the present invention, according to one example, by uniformly mixing the alloy powder that satisfies the above-described composition range, prepared by thermoforming under the conditions of temperature 140 ~ 150 ℃ and pressure 100 ~ 160kg / ㎠ do. The thermoformed moldings are preferably heat treated, ie annealed, at a temperature of 130 to 160 ° C., with good quality and least scatter at these heat treatment temperatures. Naturally, the brake disc may be manufactured by dissolving the alloying component.

Look at the experimental example for the performance evaluation of the brake disk according to the present invention.

Brake disks (Examples 1 and 2 and Comparative Examples 1 and 2) having the compositions shown in Table 1 below were manufactured. The brake discs according to Examples 1 and 2 and Comparative Examples 1 and 2 were all manufactured by thermoforming alloy powders having respective compositions under conditions of a temperature of 150 ° C. and a pressure of 150 kg / cm 2. After thermoforming it is heat-treated at 150 ℃.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Al 30 20 30 27 Cu 0.3 0.3 0.3 0.3 Cr 0.3 0.3 0.3 0.3 C 3.6 3.6 3.6 3.6 Mn 1.6 1.6 1.6 1.6 V 0.8 0.8 0.8 0.8 Mg 5.4 5.4 5.4 5.4 Ni 6.0 6.0 6.0 6.0 Fe 37 47 52 55 Graphene 15 15 - -

In the experiment, each of the brate disks according to Examples 1 and 2 and Comparative Examples 1 and 2 was subjected to a test evaluation cycle of 1 cycle, and after 6 cycles in total, the vehicle was mounted on a vehicle to perform a braking test and the surface of the disk. Observation of sticking to and progressing in a manner to evaluate the Disc Thickness Variation (DTV) and heat dissipation.

Test evaluation 1 cycle

① Constant temperature and humidity tank: Maintain 48 hours at 75 ℃, 90% humidity

② Salt spray tank: Maintain 48 hours at 35 ℃, 5% brine

③ Drying: 1 hour at 100 ℃ and 1 hour at 200 ℃

④ Natural Left: 48 hours

The results of the above experiments are shown in Table 2 below. The heat dissipation represents the cooling time until the disc temperature reaches 100 ° C. after 10 times of fading braking. Here, fade braking is a European AMS fade test method, which is performed for 9 consecutive braking cycles of 0.6 g from 0.8 Vmax to 80 KPH and one braking from 0.8 Vmax to 0 KPH.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Sticking Does not occur Does not occur Occur Occur D.T.V (μm) 2 3 8 10 Heat dissipation (seconds) 355 382 474 483

As shown in Table 2, Example 1 and Example 2 did not occur in the pressing phenomenon compared to the comparative examples, the DTV change was also insignificant, it was confirmed that the heat dissipation superior to the comparative examples.

While specific embodiments of the present invention have been illustrated and described, those of ordinary skill in the art may vary the present invention without departing from the spirit of the invention as set forth in the following claims. It is to be understood that modifications and variations are possible.

Claims (3)

By weight%, aluminum (Al) 20-30%, copper (Cu) 0.2-30%, chromium (Cr) 0.15-0.30%, carbon (C) 3.6-3.8%, manganese (Mn) 1.4-1.6%, vanadium (V) 0.4 to 0.8%, magnesium (Mg) 3.0 to 6.0%, nickel (Ni) 1.0 to 6.0%, graphene (graphene) 10 to 20%, the remaining iron and other inevitable impurities Brake discs for cars. Mixing the alloy powder; And It includes a step of thermoforming the mixed alloy powder at a temperature of 140 ~ 150 ℃, pressure 100 ~ 160Kg / ㎠; The alloy powder is, in weight percent, aluminum (Al) 20-30%, copper (Cu) 0.2-0.35%, chromium (Cr) 0.15-0.30%, carbon (C) 3.6-3.8%, manganese (Mn) 1.4 ~ 1.6%, vanadium (V) 0.4-0.8%, magnesium (Mg) 3.0-6.0%, nickel (Ni) 1.0-6.0%, graphene (10-20%), containing the remaining iron and other unavoidable impurities Brake disk manufacturing method for a vehicle, characterized in that. The method of claim 2, wherein after the thermoforming, the molded article is heat-treated at 130 to 160 ° C.