Cast iron brake disc and preparation method thereof

Abstract

The invention discloses a cast iron brake disc and a preparation method thereof. The cast iron brake disc is prepared by spraying a functional coating on a cast iron base body, and the use amount of the functional coating accounts for 8-12% of the mass of the cast iron base body. According to the cast iron brake disc prepared through the method, the rare earth oxide is added into traditional cast iron preparation raw materials, the mechanical property of the material is improved, the rare earth oxide is a compound of yttrium oxide and cerium dioxide, and synergistic interaction is achieved through compound use. The surface of the brake disc is coated with the functional coating, the wear resistance and heat resistance of the brake disc are improved, the wear resistance of the brake disc is improved through combined use of the perchloro-ethylene resin and the polyaspartic acid resin, and the heat resistance of the brake disc is improved through combined use of the sodium tungstate and the potassium titanate whiskers.

Description

Technical Field

[0001] The present invention belongs to the technical field of automotive brake discs, and particularly relates to a cast iron brake disc and a preparation method thereof. Background Art

[0002] The brake disc is a key component in the automotive braking system, and its main function is to decelerate or stop the vehicle by friction with the brake pads. Brake discs are usually made of metal materials such as cast iron, steel or composite materials, and can still maintain good performance and durability under high temperature and high load conditions. Brake discs are usually circular and fixed on the wheel hub, rotating with the wheel. When the driver steps on the brake pedal, the brake caliper clamps the brake disc, generating frictional force to decelerate or stop the vehicle.

[0003] Cast iron brake discs are a traditional material widely used in automotive braking systems, with various advantages and limitations. Cast iron materials have good wear resistance and high temperature resistance, can withstand high temperature and wear, and are suitable for long-term use. Its fracture surface is dark gray, indicating that it has certain mechanical properties. Cast iron brake discs have a high thermal conductivity, can dissipate heat quickly, prevent heat fade caused by overheating, and thus ensure the stability during continuous braking. The manufacturing process of cast iron brake discs is relatively simple, easy to process and form, and suitable for mass production. Cast iron brake discs also have some limitations. Cast iron materials are prone to oxidation and rust, especially in humid environments, which may affect their service life and performance. Under high temperature braking conditions, cast iron brake discs have poor thermal fade resistance, which may lead to a decrease in braking force. Cast iron materials have a low hardness, are prone to cracks and wear, and are not suitable for the manufacture of high-precision and high-wear-resistant parts. Summary of the Invention

[0004] The purpose of the present invention is to provide a cast iron brake disc and a preparation method thereof.

[0005] A cast iron brake disc is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 8-12% of the mass of the cast iron matrix.

[0006] The cast iron matrix is made of the following raw materials in parts by weight: 100-200 parts of pig iron, 6-8 parts of carburizer, 0.2-0.6 parts of electrolytic copper, 3-5 parts of ferromanganese, 2-4 parts of ferrochrome, and 3-5 parts of rare earth oxide.

[0007] The carburizer is graphite, petroleum coke or coke.

[0008] The ferromanganese contains Mn≥52.4%, P≤0.8%, and S≤0.05%.

[0009] The ferrochrome contains Cr≥48.2%, Si≤2.2%, Mn≤0.8%, and V≤0.3%.

[0010] The rare earth oxide is a mixture of yttrium oxide and cerium dioxide mixed in a mass ratio of 1:1.

[0011] The functional coating is composed of the following components in parts by weight: 20-30 parts of perchloroethylene resin, 20-30 parts of polyaspartic acid resin, 20-30 parts of filler, 3-5 parts of isophorone diisocyanate, 2-5 parts of dispersant, and 1-3 parts of leveling agent.

[0012] The filler is a mixture of sodium tungstate and potassium titanate whiskers mixed in a mass ratio of 1:1.

[0013] The dispersant is one or more of polyvinylpyrrolidone, sodium polyacrylate, methyl methacrylate, magnesium stearate, and methacrylate phosphate diol; the leveling agent is one or more of polydimethylsiloxane, polymethylphenylsiloxane, and n-butyl acrylate.

[0014] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0015] (1) Add pig iron, carbon additive, electrolytic copper, ferromanganese, ferrochrome, and rare earth oxide into an electric arc furnace for heating. The heating temperature is 1600-1800 °C, and keep warm for 10-20 min, then skim the slag to obtain a cast iron solution.

[0016] (2) Pour the molten cast iron solution into a pre-prepared mold, and make it fill the cavity by gravity or pressure. The casting is cooled and solidified in the mold, and a robotic arm or vibrating sand cleaning machine is used to remove the sand shell from the casting to obtain a cast iron matrix.

[0017] (3) Place the cast iron matrix in a coating chamber, heat the functional coating to 60-80 °C, and spray it onto the cast iron matrix. The dosage of the functional coating accounts for 8-12% of the mass of the cast iron matrix. After spraying, cool it naturally to room temperature.

[0018] The beneficial effects of the present invention: For the cast iron brake disc prepared by the present invention, rare earth oxide is added to the traditional cast iron preparation raw materials, which improves the mechanical properties of the material. Moreover, the rare earth oxide is a composite of yttrium oxide and cerium dioxide, and the combined use has a synergistic effect. The surface of the brake disc is coated with a functional coating, which improves the wear resistance and heat resistance of the brake disc. The combined use of perchloroethylene resin and polyaspartic acid resin improves the wear resistance of the brake disc, and the combined use of sodium tungstate and potassium titanate whiskers improves the heat resistance of the brake disc. Specific embodiments

[0019] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0020] Example 1

[0021] A cast iron brake disc, which is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 10% of the mass of the cast iron matrix.

[0022] The cast iron matrix is made of the following raw materials in parts by weight: 150 parts of pig iron, 7 parts of graphite, 0.4 parts of electrolytic copper, 4 parts of ferromanganese, 3 parts of ferrochrome, 4 parts of rare earth oxide; the ferromanganese contains 55.3% of Mn, 0.6% of P, and 0.03% of S; the ferrochrome contains 53.6% of Cr, 2.1% of Si, 0.6% of Mn, and 0.2% of V; the rare earth oxide is a mixture of yttrium oxide and cerium dioxide mixed in a mass ratio of 1:1.

[0023] The functional coating is composed of the following components in parts by weight: 25 parts of perchloroethylene resin, 25 parts of polyaspartic acid resin, 25 parts of filler, 4 parts of isophorone diisocyanate, 3 parts of polyvinylpyrrolidone, 2 parts of polydimethylsiloxane; the filler is a mixture of sodium tungstate and potassium titanate whiskers mixed in a mass ratio of 1:1.

[0024] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0025] (1) Add pig iron, graphite, electrolytic copper, ferromanganese, ferrochrome, and rare earth oxide into an electric arc furnace for heating, the heating temperature is 1700 °C, keep warm for 15 min, skim the slag, and obtain a cast iron solution;

[0026] (2) Pour the molten cast iron solution into a pre-prepared mold, and make it fill the cavity by gravity or pressure. The casting is cooled and solidified in the mold, and a robotic arm or a vibrating sand cleaning machine is used to remove the sand shell from the casting to obtain a cast iron matrix;

[0027] (3) Place the cast iron matrix in a coating chamber, heat the functional coating to 70 °C, spray it onto the cast iron matrix, and the dosage of the functional coating accounts for 10% of the mass of the cast iron matrix. After spraying, cool it naturally to room temperature.

[0028] Example 2

[0029] A cast iron brake disc, which is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 8% of the mass of the cast iron matrix.

[0030] The cast iron matrix is made of raw materials in the following parts by weight: 120 parts of pig iron, 6 parts of petroleum coke, 0.3 parts of electrolytic copper, 3 parts of ferromanganese, 2 parts of ferrochrome, and 3 parts of rare earth oxide; the ferromanganese contains 56.1% Mn, 0.2% P, and 0.02% S; the ferrochrome contains 49.4% Cr, 1.6% Si, 0.5% Mn, and 0.2% V; the rare earth oxide is a mixture of yttrium oxide and cerium dioxide mixed in a mass ratio of 1:1.

[0031] The functional coating is composed of components in the following parts by weight: 22 parts of perchloroethylene resin, 22 parts of polyaspartic acid resin, 22 parts of filler, 3 parts of isophorone diisocyanate, 3 parts of methyl methacrylate, and 1 part of polymethylphenylsiloxane; the filler is a mixture of sodium tungstate and potassium titanate whiskers mixed in a mass ratio of 1:1.

[0032] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0033] (1) Add pig iron, petroleum coke, electrolytic copper, ferromanganese, ferrochrome, and rare earth oxide into an electric arc furnace for heating. The heating temperature is 1600 °C, keep warm for 20 min, skim the slag to obtain a cast iron solution;

[0034] (2) Pour the molten cast iron solution into a pre-prepared mold, and make it fill the cavity by gravity or pressure. The casting cools and solidifies in the mold, and use a robotic arm or vibrating sand cleaning machine to remove the sand shell from the casting to obtain a cast iron matrix;

[0035] (3) Place the cast iron matrix in a coating chamber, heat the functional coating to 60 °C, spray it onto the cast iron matrix. The dosage of the functional coating accounts for 8% of the mass of the cast iron matrix. After spraying, cool it naturally to room temperature.

[0036] Example 3

[0037] A cast iron brake disc is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 12% of the mass of the cast iron matrix.

[0038] The cast iron matrix is made of raw materials in the following parts by weight: 200 parts of pig iron, 8 parts of coke, 0.6 parts of electrolytic copper, 5 parts of ferromanganese, 4 parts of ferrochrome, and 5 parts of rare earth oxide; the ferromanganese contains 54.3% Mn, 0.7% P, and 0.04% S; the ferrochrome contains 52.6% Cr, 1.6% Si, 0.5% Mn, and 0.2% V; the rare earth oxide is a mixture of yttrium oxide and cerium dioxide mixed in a mass ratio of 1:1.

[0039] The functional coating is composed of the following components in parts by weight: 30 parts of perchloroethylene resin, 30 parts of polyaspartic acid resin, 30 parts of filler, 5 parts of isophorone diisocyanate, 5 parts of methacrylate phosphate diol, and 3 parts of n-butyl polyacrylate; the filler is a mixture of sodium tungstate and potassium titanate whiskers mixed in a mass ratio of 1:1.

[0040] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0041] (1) Add pig iron, coke, electrolytic copper, ferromanganese, ferrochromium, and rare earth oxide into an electric arc furnace for heating. The heating temperature is 1800 °C, keep warm for 12 min, and skim the slag to obtain a cast iron solution;

[0042] (2) Pour the molten cast iron solution into a pre-prepared mold, and make it fill the cavity by gravity or pressure. The casting is cooled and solidified in the mold, and a robotic arm or vibrating sand cleaning machine is used to remove the sand shell from the casting to obtain a cast iron matrix;

[0043] (3) Place the cast iron matrix in a coating chamber, heat the functional coating to 80 °C, spray it onto the cast iron matrix. The dosage of the functional coating accounts for 12% of the mass of the cast iron matrix. After spraying, cool it naturally to room temperature.

[0044] Comparative Example 1

[0045] A cast iron brake disc is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 10% of the mass of the cast iron matrix.

[0046] The cast iron matrix is made of the following raw materials in parts by weight: 150 parts of pig iron, 7 parts of graphite, 0.4 parts of electrolytic copper, 4 parts of ferromanganese, 3 parts of ferrochromium, and 4 parts of yttrium oxide; the ferromanganese contains 55.3% Mn, 0.6% P, and 0.03% S; the ferrochromium contains 53.6% Cr, 2.1% Si, 0.6% Mn, and 0.2% V.

[0047] The functional coating is composed of the following components in parts by weight: 25 parts of perchloroethylene resin, 25 parts of polyaspartic acid resin, 25 parts of filler, 4 parts of isophorone diisocyanate, 3 parts of polyvinylpyrrolidone, and 2 parts of polydimethylsiloxane; the filler is a mixture of sodium tungstate and potassium titanate whiskers mixed in a mass ratio of 1:1.

[0048] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0049] (1) Add pig iron, graphite, electrolytic copper, ferromanganese, ferrochromium, and yttrium oxide into an electric arc furnace for heating. The heating temperature is 1700 °C, keep warm for 15 min, and skim the slag to obtain a cast iron solution;

[0050] (2) Pour the molten cast iron solution into a pre-prepared mold, and let it fill the cavity by gravity or pressure. The casting cools and solidifies in the mold, and then use a robotic arm or a vibrating sand cleaning machine to remove the sand shell from the casting to obtain a cast iron matrix.

[0051] (3) Place the cast iron matrix in a coating chamber, heat the functional coating to 70 °C, and spray it onto the cast iron matrix. The dosage of the functional coating accounts for 10% of the mass of the cast iron matrix. After spraying, let it cool naturally to room temperature.

[0052] Comparative Example 2

[0053] A cast iron brake disc, which is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 10% of the mass of the cast iron matrix.

[0054] The cast iron matrix is made of the following raw materials in parts by weight: 150 parts of pig iron, 7 parts of graphite, 0.4 parts of electrolytic copper, 4 parts of ferromanganese, 3 parts of ferrochrome, 4 parts of cerium dioxide; the ferromanganese contains 55.3% Mn, 0.6% P, and 0.03% S; the ferrochrome contains 53.6% Cr, 2.1% Si, 0.6% Mn, and 0.2% V.

[0055] The functional coating is composed of the following components in parts by weight: 25 parts of perchloroethylene resin, 25 parts of polyaspartic acid resin, 25 parts of filler, 4 parts of isophorone diisocyanate, 3 parts of polyvinylpyrrolidone, 2 parts of polydimethylsiloxane; the filler is a mixture of sodium tungstate and potassium titanate whiskers mixed in a mass ratio of 1:1.

[0056] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0057] (1) Add pig iron, graphite, electrolytic copper, ferromanganese, ferrochrome, and cerium dioxide into an electric arc furnace and heat it. The heating temperature is 1700 °C, keep it warm for 15 minutes, and skim the slag to obtain a cast iron solution.

[0058] (2) Pour the molten cast iron solution into a pre-prepared mold, and let it fill the cavity by gravity or pressure. The casting cools and solidifies in the mold, and then use a robotic arm or a vibrating sand cleaning machine to remove the sand shell from the casting to obtain a cast iron matrix.

[0059] (3) Place the cast iron matrix in a coating chamber, heat the functional coating to 70 °C, and spray it onto the cast iron matrix. The dosage of the functional coating accounts for 10% of the mass of the cast iron matrix. After spraying, let it cool naturally to room temperature.

[0060] Comparative Example 3

[0061] A cast iron brake disc, which is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 10% of the mass of the cast iron matrix.

[0062] The cast iron matrix is made from raw materials in the following parts by weight: 150 parts of pig iron, 7 parts of graphite, 0.4 parts of electrolytic copper, 4 parts of ferromanganese, 3 parts of ferrochrome, and 4 parts of rare earth oxide; the ferromanganese contains 55.3% Mn, 0.6% P, and 0.03% S; the ferrochrome contains 53.6% Cr, 2.1% Si, 0.6% Mn, and 0.2% V; the rare earth oxide is a mixture of yttrium oxide and cerium dioxide mixed in a mass ratio of 1:1.

[0063] The functional coating is composed of components in the following parts by weight: 50 parts of perchloroethylene resin, 25 parts of filler, 4 parts of isophorone diisocyanate, 3 parts of polyvinylpyrrolidone, and 2 parts of polydimethylsiloxane; the filler is a mixture of sodium tungstate and potassium titanate whiskers mixed in a mass ratio of 1:1.

[0064] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0065] (1) Add pig iron, graphite, electrolytic copper, ferromanganese, ferrochrome, and rare earth oxide into an electric arc furnace for heating. The heating temperature is 1700 °C, keep warm for 15 min, and skim the slag to obtain a cast iron solution.

[0066] (2) Pour the molten cast iron solution into a pre-prepared mold, and let it fill the cavity by gravity or pressure. The casting cools and solidifies in the mold, and use a robotic arm or a vibrating sand cleaning machine to remove the sand shell from the casting to obtain a cast iron matrix.

[0067] (3) Place the cast iron matrix in a coating chamber, heat the functional coating to 70 °C, and spray it onto the cast iron matrix. The dosage of the functional coating accounts for 10% of the mass of the cast iron matrix. After spraying, cool it naturally to room temperature.

[0068] Comparative Example 4

[0069] A cast iron brake disc is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 10% of the mass of the cast iron matrix.

[0070] The cast iron matrix is made from raw materials in the following parts by weight: 150 parts of pig iron, 7 parts of graphite, 0.4 parts of electrolytic copper, 4 parts of ferromanganese, 3 parts of ferrochrome, and 4 parts of rare earth oxide; the ferromanganese contains 55.3% Mn, 0.6% P, and 0.03% S; the ferrochrome contains 53.6% Cr, 2.1% Si, 0.6% Mn, and 0.2% V; the rare earth oxide is a mixture of yttrium oxide and cerium dioxide mixed in a mass ratio of 1:1.

[0071] The functional coating is composed of the following components in parts by weight: 50 parts of polyaspartic acid resin, 25 parts of filler, 4 parts of isophorone diisocyanate, 3 parts of polyvinylpyrrolidone, and 2 parts of polydimethylsiloxane; the filler is a mixture of sodium tungstate and potassium titanate whiskers mixed in a mass ratio of 1:1.

[0072] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0073] (1) Add pig iron, graphite, electrolytic copper, ferromanganese, ferrochrome, and rare earth oxide into an electric arc furnace for heating, with a heating temperature of 1700 °C, keep warm for 15 min, skim the slag, and obtain a cast iron solution;

[0074] (2) Pour the molten cast iron solution into a pre-prepared mold, and make it fill the cavity by gravity or pressure. The casting is cooled and solidified in the mold, and a robotic arm or vibrating sand cleaning machine is used to remove the sand shell from the casting to obtain a cast iron matrix;

[0075] (3) Place the cast iron matrix in a coating chamber, heat the functional coating to 70 °C, spray it onto the cast iron matrix, and the dosage of the functional coating accounts for 10% of the mass of the cast iron matrix. After spraying, cool it naturally to room temperature.

[0076] Comparative Example 5

[0077] A cast iron brake disc is prepared by spraying a functional coating on a cast iron matrix, and the dosage of the functional coating accounts for 10% of the mass of the cast iron matrix.

[0078] The cast iron matrix is made from the following raw materials in parts by weight: 150 parts of pig iron, 7 parts of graphite, 0.4 parts of electrolytic copper, 4 parts of ferromanganese, 3 parts of ferrochrome, and 4 parts of rare earth oxide; the ferromanganese contains 55.3% Mn, 0.6% P, and 0.03% S; the ferrochrome contains 53.6% Cr, 2.1% Si, 0.6% Mn, and 0.2% V; the rare earth oxide is a mixture of yttrium oxide and cerium dioxide mixed in a mass ratio of 1:1.

[0079] The functional coating is composed of the following components in parts by weight: 25 parts of perchloroethylene resin, 25 parts of polyaspartic acid resin, 25 parts of sodium tungstate, 4 parts of isophorone diisocyanate, 3 parts of polyvinylpyrrolidone, and 2 parts of polydimethylsiloxane.

[0080] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0081] (1) Add pig iron, graphite, electrolytic copper, ferromanganese, ferrochrome, and rare earth oxide into an electric arc furnace for heating, with a heating temperature of 1700 °C, keep warm for 15 min, skim the slag, and obtain a cast iron solution;

[0082] (2) Pour the molten cast iron solution into a pre-prepared mold, and let it fill the cavity by gravity or pressure. The casting cools and solidifies in the mold, and then use a robotic arm or a vibrating sand cleaning machine to remove the sand shell from the casting to obtain a cast iron substrate.

[0083] (3) Place the cast iron substrate in a coating chamber, heat the functional coating to 70 °C, and spray it onto the cast iron substrate. The dosage of the functional coating accounts for 10% of the mass of the cast iron substrate. After spraying, let it cool naturally to room temperature.

[0084] Comparative Example 6

[0085] A cast iron brake disc is prepared by spraying a functional coating on a cast iron substrate, and the dosage of the functional coating accounts for 10% of the mass of the cast iron substrate.

[0086] The cast iron substrate is made of the following raw materials in parts by weight: 150 parts of pig iron, 7 parts of graphite, 0.4 parts of electrolytic copper, 4 parts of ferromanganese, 3 parts of ferrochrome, 4 parts of rare earth oxide; the ferromanganese contains 55.3% Mn, 0.6% P, and 0.03% S; the ferrochrome contains 53.6% Cr, 2.1% Si, 0.6% Mn, and 0.2% V; the rare earth oxide is a mixture of yttrium oxide and cerium dioxide mixed in a mass ratio of 1:1.

[0087] The functional coating is composed of the following components in parts by weight: 25 parts of perchloroethylene resin, 25 parts of polyaspartic acid resin, 25 parts of potassium titanate whiskers, 4 parts of isophorone diisocyanate, 3 parts of polyvinylpyrrolidone, and 2 parts of polydimethylsiloxane.

[0088] The preparation method of the cast iron brake disc is carried out according to the following steps:

[0089] (1) Add pig iron, graphite, electrolytic copper, ferromanganese, ferrochrome, and rare earth oxide into an electric arc furnace for heating. The heating temperature is 1700 °C, keep it warm for 15 min, and skim the slag to obtain a cast iron solution.

[0090] (2) Pour the molten cast iron solution into a pre-prepared mold, and let it fill the cavity by gravity or pressure. The casting cools and solidifies in the mold, and then use a robotic arm or a vibrating sand cleaning machine to remove the sand shell from the casting to obtain a cast iron substrate.

[0091] (3) Place the cast iron substrate in a coating chamber, heat the functional coating to 70 °C, and spray it onto the cast iron substrate. The dosage of the functional coating accounts for 10% of the mass of the cast iron substrate. After spraying, let it cool naturally to room temperature.

[0092] Experimental Example 1:

[0093] The tensile strength (MPa) of the cast iron brake discs prepared in Examples 1-3 and Comparative Examples 1-2 was determined according to the provisions of GB / T 34422-2017 "Brake Discs for Motor Vehicles". Each group was measured in parallel 3 times and the average value was taken. The experimental results were statistically analyzed using SPSS 24.0 software. The results of measurement data were expressed as (mean ± standard deviation), and the Kolmogorov-Smirnov test method was used for data normality test. For data conforming to normal distribution, the t-test was used to compare the mean differences between two groups. A P<0.05 was considered statistically significant. The measurement results are shown in Table 1:

[0094] Table 1

[0095]

[0096] Note: * represents P<0.05 compared with the Example 1 group.

[0097] Experimental Example 2:

[0098] The braking performance of the brake discs prepared in Examples 1-3 and Comparative Examples 3-4 was tested using an MM-1000 friction testing machine. The test conditions were: inertia 3.8 kgf·cm·s 2 , specific pressure 100 N / cm 2 , linear velocity 25 m / s; the wear amount (mg) after 500 uses was measured. Each group was measured in parallel 3 times and the average value was taken. The experimental results were statistically analyzed using SPSS 24.0 software. The results of measurement data were expressed as (mean ± standard deviation), and the Kolmogorov-Smirnov test method was used for data normality test. For data conforming to normal distribution, the t-test was used to compare the mean differences between two groups. A P<0.05 was considered statistically significant. The measurement results are shown in Table 2:

[0099] Table 2

[0100]

[0101] Note: * represents P<0.05 compared with the Example 1 group.

[0102] Experimental Example 3:

[0103] Under the condition of 600 °C, the brake discs prepared in Examples 1-3 and Comparative Examples 5-6 were statically oxidized at a constant temperature for 30 h, and their oxidation weight loss rate (%) was measured. Each group was measured in parallel 3 times and the average value was taken. The experimental results were statistically analyzed using SPSS 24.0 software. The results of measurement data were expressed as (Mean ± Standard Deviation). The Kolmogorov-Smirnov test method was used for data normality test. For data conforming to normal distribution, the t-test was used to compare the mean differences between the two groups. A P value < 0.05 was considered statistically significant. The measurement results are shown in Table 3:

[0104] Table 3

[0105]

[0106] Note: * indicates P < 0.05 compared with the Example 1 group.

[0107] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A cast iron brake disc, characterized in that: The cast iron brake disc is prepared by spraying a functional coating on a cast iron substrate, and the amount of the functional coating accounts for 8-12% of the mass of the cast iron substrate.

2. The cast iron brake disc according to claim 1, characterized in that: The cast iron matrix is ​​made of the following raw materials in parts by weight: 100-200 parts of pig iron, 6-8 parts of carburizer, 0.2-0.6 parts of electrolytic copper, 3-5 parts of ferromanganese, 2-4 parts of ferrochrome, and 3-5 parts of rare earth oxide.

3. The cast iron brake disc according to claim 2, characterized in that: The recarburizer is graphite, petroleum coke or coke.

4. The cast iron brake disc according to claim 2, characterized in that: The ferromanganese contains Mn≥52.4%, P≤0.8%, and S≤0.05%.

5. The cast iron brake disc according to claim 2, characterized in that: The ferrochrome contains Cr≥48.2%, Si≤2.2%, Mn≤0.8% and V≤0.3%.

6. The cast iron brake disc according to claim 2, characterized in that: The rare earth oxide is a mixture of yttrium oxide and cerium dioxide in a mass ratio of 1:

1.

7. The cast iron brake disc according to claim 1, characterized in that: The functional coating is composed of the following components in parts by weight: 20-30 parts of perchlorethylene resin, 20-30 parts of polyaspartic acid resin, 20-30 parts of filler, 3-5 parts of isophorone diisocyanate, 2-5 parts of dispersant and 1-3 parts of leveling agent.

8. The cast iron brake disc according to claim 7, characterized in that: The filler is a mixture of sodium tungstate and potassium titanate whiskers in a mass ratio of 1:

1.

9. The cast iron brake disc according to claim 7, characterized in that: The dispersant is one or more of polyvinyl pyrrolidone, sodium polyacrylate, methyl methacrylate, magnesium stearate, and methacrylate phosphate diol; the leveling agent is one or more of polydimethylsiloxane, polymethylphenylsiloxane, and polybutyl acrylate.

10. The method for preparing the cast iron brake disc according to claim 1, characterized in that: Follow these steps: (1) Add pig iron, carburizer, electrolytic copper, ferromanganese, ferrochrome and rare earth oxide into an electric arc furnace and heat at a temperature of 1600-1800°C for 10-20 minutes, remove the slag and obtain a cast iron solution; (2) Pour the molten cast iron solution into a pre-prepared mold, fill the mold cavity by gravity or pressure, cool and solidify the casting in the mold, and use a robotic arm or a vibrating sand cleaning machine to remove the sand shell from the casting to obtain a cast iron matrix; (3) Place the cast iron substrate in a coating room, heat the functional coating to 60-80°C, and spray it onto the cast iron substrate. The amount of functional coating accounts for 8-12% of the mass of the cast iron substrate. After spraying, cool it naturally to room temperature.

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