CN113801373B - Friction filler, friction material composition, friction material and application thereof - Google Patents

Abstract

The invention provides a friction filler, a friction material composition, a friction material and application thereof. The friction filler comprises: 14.6-18.1 parts of barium sulfate, 9.2-10.6 parts of crystalline flake graphite, 3.9-4.9 parts of metal scraps, 6.6-7.8 parts of reduced iron powder, 2.5-3.3 parts of zirconium dioxide, 3.3-4.8 parts of white corundum, 4.5-5.2 parts of cryolite, 0.47-0.63 part of chlorinated fatty acid and 3.8-4.7 parts of potassium feldspar. The invention also provides a friction material composition comprising a binder, reinforcing fibers and the friction filler described above. The invention further provides a friction material prepared from the friction material composition and application of the friction material in cleaning the tread of a railway vehicle. The friction material can effectively improve the adhesion coefficient between the wheel rails, play a role in repairing the wheels, prolong the whole service life of the wheels and improve the dynamic state between the wheel rails.

Description

Friction filler, friction material composition, friction material and application thereof

technical field

The invention relates to the technical field of applying rail vehicle wheel tread cleaning friction, in particular to a friction filler suitable for wheel tread cleaning, a friction material composition, a friction material and an application thereof.

Background technique

During the operation of the rail vehicle, the braking friction and traction friction of the vehicle depend on the adhesion coefficient between the wheel and the rail. The braking and traction design of the rail vehicle is based on the corresponding wheel-rail adhesion. Avoid wheel sliding and idling, reduce the probability of wheel and rail damage. Due to the diversification of the operating environment, there are many kinds of pollutants between the wheel and the track. At the same time, due to the wide and complex sources of pollutants, the adhesion coefficient between the wheel and the rail will decrease, which may cause the wheel to slide during the braking process. Idling during traction can cause damage to rails and wheels. At the same time, due to the influence of the wavy wear of the track and the unevenness of the track, the tread of the wheel is prone to polygonal wear during operation, which affects the dynamic state between the wheel and the rail. Therefore, it is necessary to develop tread grinding materials for cleaning and grinding the wheel surface. , so that the adhesion coefficient between the wheel and rail can be effectively improved, the idling or sliding of the wheel can be reduced, and the wheel can be repaired, thereby improving the overall service life of the wheel and improving the dynamic state between the wheel and rail. The existing grinding sub-materials of tread cleaners have the following problems during use: 1. Metal inlays that are harmful to wheels are prone to appear in wet, rainy and snowy environments; Noise occurs during the process; 3. The abrasive sub-material is prone to thermal cracks during frequent and repeated braking, so that the cracks expand to form abrasive material pieces; 4. The abrasive material has limited cleaning and repair effects, and the effect of eliminating polygonal contours on the wheel surface is not good. Good; 5. The wear resistance of the abrasive sub-material is insufficient.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a friction filler, a friction material composition, a friction material and applications thereof. The friction material is applied to the wheel tread cleaning of rail vehicles, which can effectively improve the adhesion coefficient between the wheel and rail, play a role in repairing the wheel, improve the overall service life of the wheel and improve the dynamic state between the wheel and rail.

In order to achieve the above object, the present invention provides a friction filler, wherein, in parts by mass, the friction filler includes: 14.6-18.1 parts of barium sulfate, 9.2-10.6 parts of flake graphite, 3.9-4.9 parts of copper scrap, reduced iron powder 6.6-7.8 parts, 2.5-3.3 parts of zirconia, 3.3-4.8 parts of white corundum, 4.5-5.2 parts of cryolite, 0.47-0.63 parts of chlorinated fatty acid, 3.8-4.7 parts of potassium feldspar.

In the above-mentioned friction filler, the chlorinated fatty acid, as an extreme pressure additive containing active groups, can be decomposed at high temperature during the friction process, and the decomposed products can interact with the metal in the wheel to generate shear stress and melting point. The wheel metal is low in sulfides, phosphides and halides, thereby preventing contact closure and forming a protective layer on the wheel surface to avoid the occurrence of metal inlays.

In the above-mentioned friction filler, the reduced iron powder and metal shavings can synergistically improve the thermal conductivity of the friction filler and avoid harmful thermal effects on the wheel during the cleaning process. The reduced iron powder generally uses reduced iron powder with a particle size of 100-150 mesh. The iron content of the reduced iron powder is generally above 99%.

In the above friction filler, the metal shavings may include copper shavings, such as red copper shavings. The particle size of the metal shavings is generally 40 mesh to 60 mesh, for example 40 mesh.

Among the above-mentioned friction fillers, the zirconia and white corundum have good self-sharpening properties, can play a role of modification during the friction process, and can effectively improve the cleaning ability. The zirconium dioxide can be selected from 300 mesh to 400 mesh, for example, 325 mesh zirconium dioxide. The zirconium oxide content of the zirconium dioxide is generally above 99%.

In the aforementioned friction filler, the particle size of the white corundum may be 250 mesh to 350 mesh, for example, 325 mesh. The alumina content in the white corundum is generally above 98%.

In the friction filler mentioned above, the flake graphite can lubricate the wheel tread and reduce the abnormal abrasion of the wheel surface. The flake graphite may include L185 flake graphite and the like.

Among the friction fillers mentioned above, the barium sulfate can improve the cleanliness of the wheel surface and have the effect of eliminating microcracks. The barium sulfate can be selected from a particle size of 300 mesh to 400 mesh, such as 325 mesh barium sulfate.

In the above-mentioned friction filler, the potassium feldspar plays a role of sweeping particles. The potassium feldspar can be selected from potassium feldspar with a particle size of 250 mesh to 350 mesh, for example, 325 mesh potassium feldspar.

In the above-mentioned friction filler, the cryolite with a particle size of 300 mesh to 400 mesh, such as 325 mesh, can be selected as the cryolite.

The present invention also provides a friction material composition, wherein, based on the total mass of the composition as 100%, the friction material composition includes 30.1-34.4% binder, 11.8-14% reinforcing fiber, and the balance is the above friction Filler; wherein, the binder includes nitrile rubber and phenolic resin, and the reinforcing fiber includes copper fiber.

In the above friction material composition, the phenolic resin has a relatively high thermal decomposition temperature, and it can synergistically improve the toughness of the material after being blended with the nitrile rubber and hot-pressed. The mass ratio of the nitrile rubber to the phenolic resin may be 7.5-9.6:22.6-24.8.

In the above friction material composition, the nitrile rubber may include nitrile rubber powder HLN40.

In the above friction material composition, the phenolic resin generally includes a boron-modified phenolic resin. The boron-modified phenolic resin can be a boron-modified phenolic resin with a particle size of 325 mesh.

In a specific embodiment of the present invention, the curing time of the boron-modified phenolic resin at 150-155°C is generally 70s-80s.

In the above friction material composition, the copper fiber has high thermal conductivity and strength, and the metal shavings and reduced iron powder in the friction filler can synergistically improve the thermal conductivity of the friction material. In addition, the copper fibers can also rub and clean the wheels without damaging the wheels. In a specific embodiment of the present invention, the length of the copper fiber is generally 3mm-5mm.

In a specific embodiment of the present invention, based on the total mass of the composition as 100%, the friction material composition may include 30.1%-34.4% binder, 11.8%-14% reinforcing fiber, 14.6%-18.1% barium sulfate , 9.2%-10.6% flake graphite, 3.9%-4.9% (such as 3.9%-4.8%) metal filings, 6.6%-7.8% (such as 6.6%-7.6%) reduced iron powder, 2.5%-3.3% (such as 2.5 %-3.2%) zirconia, 3.8%-4.8% (eg 3.8%-4.3%) white corundum, 4.5%-5.2% cryolite, 0.47%-0.63% (eg 0.47%-0.62%) chlorinated fatty acids Esters, 3.8%-4.7% potassium feldspar.

In a specific embodiment of the present invention, based on the total mass of the composition as 100%, the friction material composition may include 7.5%-9.6% nitrile rubber, 22.6%-24.8% phenolic resin, 11.8%-14% copper fiber , 14.6%-18.1% barium sulfate, 9.2%-10.6% flake graphite, 3.9%-4.9% copper filings, 6.6%-7.8% reduced iron powder, 2.5%-3.3% zirconium dioxide, 3.8%-4.8% white corundum , 4.5%-5.2% cryolite, 0.47%-0.63% chlorinated fatty acid ester, 3.8%-4.7% potassium feldspar.

In a specific embodiment of the present invention, the above friction material combination may further include a rubber vulcanization aid. The rubber vulcanization assistant can adjust the vulcanization rate and vulcanization degree of the rubber, and then adjust the overall vulcanization performance of the adhesive. The mass of the rubber vulcanization aid is generally determined according to the amount of rubber, for example, it may be 25%-40% of the mass of the nitrile rubber.

In the above friction material composition, the rubber vulcanization aid generally includes accelerator CZ, stearic acid, zinc oxide, vulcanizing agent (such as sulfur, etc.). Preferably, the mass ratio of the accelerator CZ, stearic acid, zinc oxide, and vulcanizing agent is 1:1:1:1.

In a specific embodiment of the present invention, the friction material composition may include binder, reinforcing fiber, friction filler and rubber vulcanization aid, wherein the total mass of binder, reinforcing fiber and friction filler is 100% In total, the friction material composition includes 7.5%-9.6% nitrile rubber, 22.6%-24.8% phenolic resin, 11.8%-14% copper fiber, 14.6%-18.1% barium sulfate, 9.2%-10.6% flake graphite, 3.9%-4.9% copper filings, 6.6%-7.8% reduced iron powder, 2.5%-3.3% zirconia, 3.8%-4.8% white corundum, 4.5%-5.2% cryolite, 0.47%-0.63% chlorinated fat Ester, 3.8%-4.7% potassium feldspar, and 25%-40% rubber vulcanization auxiliary agent whose mass is that of nitrile rubber.

The present invention also provides a friction material, which is made of the above friction material composition.

In a specific embodiment of the present invention, the preparation method of the friction material generally includes: mixing the friction material composition at high speed, adding a wetting agent, stirring evenly, hot pressing, and secondary curing to obtain the friction material.

In the above preparation method of the friction material, the wetting agent is used to improve the uniformity of the mixed materials. The mass of the wetting agent is generally 1% of the total mass of the friction material composition. Wetting agent can choose toluene etc. for use.

In the above-mentioned preparation method of the friction material, the stirring speed is generally controlled at 50-60 r/min, and the stirring time is generally controlled at 35-45 min.

In the preparation method of the above friction material, the temperature of the hot pressing is generally controlled at 155-165°C, the time of the hot pressing is generally controlled at 30-40min, and the pressure of the hot pressing is generally controlled at 25-35MPa.

In the above-mentioned preparation method of the friction material, the secondary curing generally adopts step temperature treatment to cure and stabilize the properties of the material. The secondary curing stage can be followed in sequence: heat preservation at 80°C for 1 hour, heat preservation at 100°C for 0.5 hours, heat preservation at 120°C for 1 hour, heat preservation at 140°C for 1 hour, heat preservation at 160°C for 2 hours, and finally heat preservation at 170°C for 3 hours to complete the secondary curing.

In a specific embodiment of the present invention, the preparation method of the friction material may specifically include: putting the friction material composition into a mixer for high-speed mixing, and simultaneously adding 1% of the total mass of the friction material composition for wetting Mix the agent to form the material, use a high-speed mixer to stir at a high speed of 50-60r/min for 35-45min, then put the material into a mold that is heated to 160±5°C, and use a high-speed mixer at a temperature of 155-165°C and 25-30MPa Press and heat for 30-40 minutes. After hot pressing, put the material into an oven for secondary curing, that is, heat at 80°C for 1 hour, 100°C for 0.5 hours, 120°C for 1 hour, 140°C for 1 hour, and 160°C for 2 hours. Finally, it is kept at 170° C. for 3 hours, and the friction material is obtained after secondary curing is completed.

The present invention also provides the application of the above-mentioned friction material in cleaning the wheel treads of rail vehicles. The friction material has high wear resistance and mechanical strength when applied to the wheel tread cleaning process, and can effectively improve the adhesion and cracks of the wheel, repair the wheel, and increase the service life of the wheel.

The beneficial effects of the present invention are:

1. The friction material provided by the invention can be applied to the tread cleaning process of the wheel, and the adhesion between the wheel and the rail can be improved by forming a film layer with the wheel tread; at the same time, the material also has a grinding function, which can effectively eliminate tiny cracks on the wheel surface and the out-of-roundness of the wheel, thereby improving the service life of the wheel; through friction on the surface of the wheel, the static friction coefficient between it and the rail can be improved, so that the adhesion coefficient calculated by traction and braking can be improved, and the wheel can be reduced due to idling in rainy and snowy days. Damage caused by slipping.

2. The friction material provided by the present invention has a good matching of strength and toughness, can avoid the occurrence of falling blocks during use, and has good wear resistance. The overall thermal conductivity of the friction material prevents harmful thermal effects on the wheel during sweeping. The friction material can also effectively repair the shape during the friction process, significantly improve the cleaning ability and shape repair ability, and can form a protective layer on the wheel surface to avoid the occurrence of metal inlays. The friction material of the invention does not contain poisonous or heavy metal substances, is environmentally friendly and pollution-free, has wide source of raw materials and simple preparation method.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

In the following examples, the national standards on which each performance parameter determination method is based are as follows: Compressive Strength GB/T 1041 Determination of Plastic Compressive Properties; Impact Strength GB/T 1043.1 Determination of Plastic Charpy Impact Performance Part 1: Non- Instrumented impact test; Hardness GB/T 3398.2 Determination of hardness of plastics Part 2: Rockwell hardness;

For the friction cleaning performance test, refer to the rail vehicle scaled friction brake test bench to test its static friction friction coefficient, wear amount, and repair performance. The test method is as follows:

A. Test the coefficient of static friction. Use abrasive cleaning material samples to rub the surface of the wheel. The original roughness of the wheel surface is Ra 0.3-0.4. After friction cleaning, test the coefficient of static friction between the wheel and rail samples. Among them, the friction cleaning speed is 100km/h, the cleaning pressure is 5KN, continuous braking is 20s, separation is 10s, repeated braking is 10 times, the wheel-rail static friction test pressure is 10KN, and the axle load is calculated according to the axle load of 16 tons.

B. Abrasion test, according to the frictional cleaning speed of 100km/h, cleaning pressure of 5KN, continuous braking for 20s, separation for 10s, and repeated cleaning 100 times to calculate the volumetric wear of the abrasive, the smaller the wear, the better the wear resistance of the cleaned abrasive material. high.

C. Repairing performance, according to the friction cleaning speed of 100km/h, cleaning pressure of 5KN, continuous braking for 20s, separation for 10s, and repeated cleaning 100 times, calculate the front and rear mass loss of the wheel. The greater the wheel mass loss, the greater the friction repair performance of the abrasive the better.

Key manufacturing and testing equipment: rail vehicle scaling friction brake test bench, model TM-Ⅱ, manufactured by Xi'an Shuntong Electromechanical Technology Research Institute; mixing machine, model W-200, Jiangsu Rongde Machinery Co., Ltd.; hydraulic pressure Press, model 315 tons, Nantong Juneng Forging Machinery Co., Ltd. Curing oven, up to 250°C, Ningbo Hongling Electric Oven Co., Ltd. Hot pressing mold, Zhengzhou Sanhuan Mold Co., Ltd.

Raw material: basic material: phenolic resin particles are boron-modified phenolic resin with a particle size of 325 mesh produced by Sumitomo Bakelite Co., Ltd., and the curing speed of the boron-modified phenolic resin is 70-80 seconds at 155-150°C;

The nitrile rubber is nitrile rubber powder HLN40, and the manufacturer is Huangshan Hualan Technology Co., Ltd.;

The reduced iron powder is primary reduced iron powder of 100-150 mesh, the iron content is greater than 99%, and the manufacturer is Daye City Duxin Friction Powder Co., Ltd.;

The particle size of cryolite is 325 mesh, and the cryolite with fluorine mass content ≥ 50% is manufactured by Daye City Duxin Friction Powder Co., Ltd.;

The particle size of zirconia is 325 mesh, and the zirconia content is greater than 99%. The manufacturer is Xingyang Shenzhou Abrasives Co., Ltd.;

The particle size of white corundum is 325 mesh, the alumina content is greater than 98%, and the manufacturer is Xingyang Shenzhou Abrasive Co., Ltd.;

The length of the copper fiber is 3mm-5mm, the copper content is ≥99.5%, and the manufacturer is Shijiazhuang Shuomao Friction Material Technology Co., Ltd.;

The particle size of copper shavings is 40 mesh, and the copper content is ≥99.5%. The manufacturer is Shijiazhuang Shuomao Friction Material Technology Co., Ltd.;

The particle size of barium sulfate is 325 mesh, the content of barium sulfate is greater than 98%, and the manufacturer is Shijiazhuang Xinji Chemical Co., Ltd.;

The flake graphite is L185, and the manufacturer is Datong Zhaojiayao Graphite Mine;

Potassium feldspar powder is 325 mesh, the potassium oxide content is greater than 7%, and the manufacturer is Shijiazhuang Chenxing Industrial Co., Ltd.

The manufacturer of chlorinated fatty acid esters is Zhengzhou Junlei Chemical Products Co., Ltd.;

Accelerator CZ, zinc oxide, stearic acid and sulfur are commercially available industrial products.

Comparative example 1

This comparative example provides a kind of friction material, and its preparation method comprises:

1. Weigh 500g of nitrile rubber powder, 1000g of phenolic resin powder, 600g of barium sulfate, 500g of flake graphite, 690g of copper fiber, 240g of copper filings, 386g of reduced iron powder, 102g of zirconium dioxide, 150g of white corundum, 204g of cryolite, chlorine 30g fatty acid ester, 243g potassium feldspar, 50g zinc oxide, 50g accelerator, 50g stearic acid, 50g sulfur.

2. Pour the above-mentioned weighed raw materials into the production type double-cone high-speed mixer, and at the same time add toluene whose mass is 1% of the total mass of the above-mentioned raw materials as a molding aid, set the machine speed to 60 rpm, and mix for 35 minutes After mixing evenly, the formed mixture is hot-pressed and formed by a 315-ton hydraulic press, with a forming pressure of 30 MPa, a hot-pressing temperature of 160° C., and a hot-pressing time of 35 minutes. After hot pressing, according to the curing procedure shown in Table 1, use an oven to perform secondary curing on the hot pressing formed material to obtain a friction material, which can be used as a cleaning and grinding product.

Table 1

serial number Curing temperature (°C) Holding time (h) 1 80 1 2 100 0.5 3 120 1 4 140 1 5 160 2 6 170 3

Performance tests were performed on the friction material of Comparative Example 1, and the results are shown in Table 2.

Table 2

Comparative example 2

This comparative example provides a kind of friction material, and its preparation method comprises:

1. Weigh 300g of nitrile rubber powder, 1200g of phenolic resin powder, 950g of barium sulfate, 400g of flake graphite, 500g of copper fiber, 160g of copper filings, 280g of reduced iron powder, 160g of zirconium dioxide, 250g of white corundum, 247g of cryolite, chlorine 18g fatty acid ester, 180g potassium feldspar, 30g zinc oxide, 30g accelerator, 30g stearic acid, 30g sulfur.

2. Pour the weighed above-mentioned raw materials into the production-type double-cone high-speed mixer, and at the same time add toluene whose mass is 1% of the total mass of the above-mentioned raw materials, set the machine speed to 60 rpm, mix for 35 minutes, and mix well Finally, the formed mixture was hot-pressed with a 315-ton hydraulic press, with a molding pressure of 30 MPa, a hot-pressing temperature of 160° C., and a hot-pressing time of 35 minutes. After hot pressing, according to the curing program set in Table 1, use an oven to perform secondary curing on the hot pressing formed material to obtain a friction material, which can be used as a cleaning and grinding product.

Performance tests were performed on the friction material of Comparative Example 2, and the results are shown in Table 3.

table 3

Example 1

This embodiment provides a friction material, the preparation method of which includes:

1. Weigh 350g of nitrile rubber powder, 1150g of phenolic resin powder, 840g of barium sulfate, 430g of flake graphite, 550g of copper fiber, 183g of copper filings, 310g of reduced iron powder, 150g of zirconium dioxide, 200g of white corundum, 240g of cryolite, chlorine 22g fatty acid ester, 220g potassium feldspar, 35g zinc oxide, 35g accelerator, 35g stearic acid, 35g sulfur.

2. Pour the weighed raw materials into the production type double-cone high-speed mixer, and add toluene with a mass of 1% of the total mass of the above raw materials at the same time, set the machine speed to 60 rpm, mix for 35 minutes, and mix well. The obtained mixture was hot-pressed with a 315-ton hydraulic press, with a molding pressure of 30 MPa, a hot-pressing temperature of 160° C., and a hot-pressing time of 35 minutes. After hot-press forming, according to the set curing program, use an oven to perform secondary curing on the hot-press-formed material to obtain a friction material, which can be used as a cleaning and grinding product.

Performance tests were performed on the friction material of Example 1, and the results are shown in Table 4.

Table 4

Example 2

This embodiment provides a friction material, the preparation method of which includes:

1. Weigh 400g of nitrile rubber powder, 1100g of phenolic resin powder, 760g of barium sulfate, 460g of flake graphite, 600g of copper fiber, 201g of copper filings, 330g of reduced iron powder, 120g of zirconium dioxide, 220g of white corundum, 230g of cryolite, chlorine 24g fatty acid ester, 200g potassium feldspar, 40g zinc oxide, 40g accelerator, 40g stearic acid, 40g sulfur.

2. Pour the weighed raw materials into the production-type double-cone high-speed mixer, set the machine speed to 60 rpm, and mix for 35 minutes. After mixing evenly, use the 315-ton hydraulic press to heat-press the above-mentioned mixture to form it. The pressure is 30MPa, the hot-pressing temperature is 160°C, and the hot-pressing time is 35min. After hot-press forming, according to the set curing program, use an oven to perform secondary curing on the hot-press-formed material to obtain a friction material, which can be used as a cleaning and grinding product.

Performance tests were performed on the friction material of Example 2, and the results are shown in Table 5.

table 5

Example 3

This embodiment provides a friction material, the preparation method of which includes:

1. Weigh 450g of nitrile rubber powder, 1050g of phenolic resin powder, 680g of barium sulfate, 490g of flake graphite, 650g of copper fiber, 226g of copper filings, 360g of reduced iron powder, 140g of zirconium dioxide, 180g of white corundum, 210g of cryolite, chlorine 29g fatty acid ester, 180g potassium feldspar, 45g zinc oxide, 45g accelerator, 45g stearic acid, 45g sulfur.

2. Pour the weighed raw materials into the production type double-cone high-speed mixer, and add toluene with a mass of 1% of the total mass of the above raw materials at the same time, set the machine speed to 60 rpm, mix for 35 minutes, and mix well. The formed mixture was hot-pressed using a 315-ton hydraulic press, with a molding pressure of 30 MPa, a hot-pressing temperature of 160° C., and a hot-pressing time of 35 minutes. After hot-press forming, according to the set curing program, use an oven to perform secondary curing on the hot-press-formed material to obtain a friction material, which can be used as a cleaning and grinding product.

Performance tests were performed on the friction material of Example 3, and the results are shown in Table 6.

Table 6

The composition and performance test results of the friction materials prepared in Comparative Example 1 to Comparative Example 2 and Example 1 to Example 3 are summarized in Table 7.

Table 7

Comparing the above test results, it can be seen that when the amount of each component in the friction material composition is too much or too little, the mechanical properties, wear resistance and repair performance of the friction material will be significantly reduced. In the present invention, by selecting suitable components and controlling the dosage of each component within a suitable range, the formed friction material composition can realize the tread cleaning function as a whole, and improve adhesion and wheel out-of-roundness.

Claims (26)

1. A friction filler, wherein the friction filler comprises, in parts by mass: 14.6-18.1 parts of barium sulfate, 9.2-10.6 parts of crystalline flake graphite, 3.9-4.9 parts of metal scraps, 6.6-7.8 parts of reduced iron powder, 2.5-3.3 parts of zirconium dioxide, 3.3-4.8 parts of white corundum, 4.5-5.2 parts of cryolite, 0.47-0.63 part of chlorinated fatty acid ester and 3.8-4.7 parts of potassium feldspar;

the metal scraps comprise copper scraps.

2. The friction filler according to claim 1, wherein the reduced iron powder has a particle size of 100 to 150 mesh;

the copper scraps comprise red copper scraps;

the granularity of the zirconium dioxide is 300-400 meshes;

the granularity of the white corundum is 250-350 meshes;

the granularity of the cryolite is 300-400 meshes;

the granularity of the barium sulfate is 300-400 meshes;

the granularity of the potassium feldspar is 250-350 meshes;

the flake graphite comprises L185 flake graphite.

3. The friction filler according to claim 2, wherein the metal shavings have a particle size of 40-60 mesh.

4. The friction filler according to claim 2, wherein the metal shavings have a particle size of 40 mesh.

5. The friction filler according to claim 2, wherein the particle size of the zirconium dioxide is 325 mesh.

6. A friction filler according to claim 2, wherein the white corundum has a particle size of 325 mesh.

7. The friction filler according to claim 2, wherein the cryolite has a particle size of 325 mesh.

8. The friction filler according to claim 2, wherein the particle size of the barium sulfate is 325 mesh.

9. The friction filler according to claim 2, wherein the potassium feldspar has a particle size of 325 mesh.

10. A friction material composition comprising 30.1 to 34.4% of a binder, 11.8 to 14% of reinforcing fibers, and the balance of the friction filler according to any one of claims 1 to 9, based on 100% of the total mass of the composition;

wherein the binder comprises nitrile rubber and phenolic resin, and the reinforcing fibers comprise copper fibers.

11. The friction material composition of claim 10, wherein the mass ratio of nitrile rubber to phenolic is 7.5-9.6:22.6-24.8.

12. The friction material composition of claim 11, wherein the nitrile rubber comprises nitrile rubber powder HLN40 and the phenolic resin comprises a boron modified phenolic resin.

13. The friction material composition of claim 12, wherein the boron modified phenolic resin has a particle size of 325 mesh and a cure time of 70s to 80s at 150 to 155 ℃.

14. The friction material composition of claim 10, wherein the copper fibers have a length of 3mm-5mm.

15. A friction material composition according to any one of claims 10 to 14, wherein the friction material composition comprises, based on 100% total composition mass, 30.1% to 34.4% binder, 11.8% to 14% reinforcing fibres, 14.6% to 18.1% barium sulphate, 9.2% to 10.6% crystalline graphite, 3.9% to 4.9% metal shavings, 6.6% to 7.8% reduced iron powder, 2.5% to 3.3% zirconium dioxide, 3.8% to 4.8% white corundum, 4.5% to 5.2% cryolite, 0.47% to 0.63% chlorinated fatty acid ester, 3.8% to 4.7% potassium feldspar.

16. The friction material composition according to claim 15, wherein the friction material composition comprises 7.5% -9.6% nitrile rubber, 22.6% -24.8% phenolic resin, 11.8% -14% copper fiber, 14.6% -18.1% barium sulfate, 9.2% -10.6% crystalline graphite, 3.9% -4.9% metal chips, 6.6% -7.8% reduced iron powder, 2.5% -3.3% zirconium dioxide, 3.8% -4.8% white corundum, 4.5% -5.2% cryolite, 0.47% -0.63% chlorinated fatty acid ester, 3.8% -4.7% potassium feldspar, based on 100% total mass of the composition.

17. The friction material composition of any one of claims 10-14, 16, wherein the friction material composition further comprises a rubber vulcanization aid, the mass of the rubber vulcanization aid being 25% -40% of the mass of the nitrile rubber.

18. The friction material composition of claim 17, wherein the rubber vulcanization aid comprises accelerators CZ, stearic acid, zinc oxide, vulcanizing agents.

19. The friction material composition of claim 18, wherein the mass ratio of promoter CZ, stearic acid, zinc oxide, vulcanizing agent is 1:1:1:1.

20. The friction material composition of claim 18, wherein the vulcanizing agent comprises sulfur.

21. The friction material composition of claim 15, wherein the friction material composition further comprises a rubber vulcanization aid, the mass of the rubber vulcanization aid being 25% -40% of the mass of the nitrile rubber.

22. The friction material composition of claim 21, wherein the rubber vulcanization aid comprises accelerators CZ, stearic acid, zinc oxide, vulcanizing agents.

23. The friction material composition of claim 22, wherein the mass ratio of promoter CZ, stearic acid, zinc oxide, vulcanizing agent is 1:1:1:1.

24. The friction material composition of claim 22, wherein the vulcanizing agent comprises sulfur.

25. A friction material made from the friction material composition of any one of claims 10-24.

26. Use of the friction material of claim 25 in tread cleaning of rail vehicles.