CN109306440B

CN109306440B - C-C-B4C-combined tread sweeper grinder and preparation method thereof

Info

Publication number: CN109306440B
Application number: CN201811499028.9A
Authority: CN
Inventors: 贺子铭; 彭程林
Original assignee: Maanshan City Leishi Track Traffic Equipment Co ltd
Current assignee: Maanshan City Leishi Track Traffic Equipment Co ltd
Priority date: 2018-12-08
Filing date: 2018-12-08
Publication date: 2021-11-05
Anticipated expiration: 2038-12-08
Also published as: CN109306440A

Abstract

The invention discloses a C-C-B₄C combines tread sweeper to grind son and preparation method thereof belongs to the track traffic equipment field. The method comprises the steps of putting 5-10% of a binding agent, 10-20% of graphite, 10-25% of carbon fiber, 10-20% of copper fiber, 5-8% of boron carbide and 40-50% of iron powder into a mixer for homogenization for 10-20 minutes, then adding 5-10% of an organic solvent, then granulating for 2-5 minutes, discharging, then putting the material into a drying roller for rotary secondary granulation and drying until the volatile matter is less than 1%, thus obtaining a qualified mixture, then cold press molding, curing and firing to obtain C-C-B₄And C, combining a tread sweeper grinder. The invention adopts a carbon-carbon combination mode, effectively avoids the heat fading generated by the grinding mill in the friction process, and the boron carbide is used as a reinforcing auxiliary agent and combined with the carbon and the carbon, so that the structure is stable, and the slag falling condition can not occur in the friction process.

Description

C-C-B4C-combined tread sweeper grinder and preparation method thereof

Technical Field

The invention belongs to the field of rail transit equipment, and particularly relates to a C-C-B₄C, combining the tread sweeper grinder and a preparation method thereof.

Background

The tread sweeper plays a role in sweeping the wheel and increasing the adhesion coefficient of a wheel rail to ensure the safety of service braking, and a part of the tread sweeper directly acting on the wheel is called a grinder. The grinder is a friction part with the functions of cleaning, thickening, rounding and the like in the tread cleaner, and is formed by solidifying the grinder after counter-pressing and molding in view of the functions. In the production process of the grinder, phenolic resin is generally used as a binding agent for hot press molding, the temperature is rapidly increased in the friction process, so that the resin is thermally decomposed, the binding force is reduced, the friction force of the grinder is further rapidly reduced, the phenomenon of slag falling of the grinder is serious, and in addition, the odor generated by volatilization of organic matters in the thermal decomposition process of the resin is dispersed in the atmosphere, and the adverse effect on the environment can be possibly generated.

In order to solve the above problems, through search, chinese patent CN102432978A discloses an abrasive for a motor car tread sweeper, which is made of a composite material, and the components of the composite material comprise modified phenolic resin 6818, reduced iron powder, copper fiber, steel fiber, sepiolite, potash feldspar, graphite, cryolite and alumina; for another example, chinese patent CN107915951A discloses a grinder for high-speed motor cars, which is made of a composite material composed of phenolic resin, steel fiber, copper-aluminum powder, carbon fiber, tungsten carbide, aramid fiber, black iron oxide, nitrile rubber, and an accelerator; for another example, chinese patent CN108839640A discloses a grinder for high-speed motor train units and a preparation method thereof, wherein the grinder is composed of a friction material and a steel backing, the friction material is composed of components such as phenolic resin with specific physical properties, reinforcing fibers and fillers, the friction material components need to be subjected to pretreatment such as mixing and drying, and the steel backing needs to be subjected to pretreatment such as sand blasting and resin glue spraying; then, preparing the pre-treated friction material and the steel backing together through special hot press molding, heat treatment and other processes to obtain a grinder; further, as disclosed in chinese patent CN108359212A, a grinding wheel for rail vehicles and a method for preparing the same, the grinding wheel comprises the following raw materials: phenolic resin, potassium feldspar, barium sulfate, graphite, wollastonite cotton, copper fiber, iron powder, aluminum oxide and sepiolite; for another example, chinese patent CN107188456A discloses a shape-modifying grinder for a motor car tread sweeper and a preparation method thereof, which comprises the following steps: 10-35% of binder, 5-15% of nitrile rubber, 10-20% of carbon fiber and 5-E10% of modification auxiliary agent, 15-35% of graphite and 0-10% of graphite; then the raw materials are added into a high-speed plow-rake type mixer according to the proportion and in steps, mixed for 5-10 min, and the mixture is put into a forming die at the temperature of room temperature-150 ℃ at the volume of 200-600 kg/cm²The pressure reaction is carried out for 200-500 seconds, and then the formed grinding particles are sintered at a high temperature, wherein the sintering temperature is 100-140 ℃, and the sintering time is 5-20 hours, so that the grinding particles are obtained.

By analyzing the content of the patent, because the resin can carry out condensation reaction after being heated to a certain temperature and simultaneously emit gas, the resin can increase the strength of the product but also emit a large amount of gas at the same time, thereby increasing the difficulty of gas exhaust; in addition, during the hot press molding process, the temperature also affects the performance of the abrasive, for example, the surface of the abrasive will solidify rapidly, the internal gas will not be discharged easily, and bubbles and cracks are easily generated.

Disclosure of Invention

1. Problems to be solved

Aiming at the problems that the existing grinder has serious slag falling phenomenon caused by the thermal decomposition of resin and the resin can generate thermal decomposition to release organic gas possibly causing adverse effects on the environment in the friction process, the invention provides a C-C-B₄The C combined tread sweeper grinder and the preparation method thereof enable the resin to be decomposed and completed in the production and manufacturing stage and form a carbon combined network, and the B is utilized in the using process₄C prevents oxidation of the carbon-bonded network and forms B₂O₃This low-melting product, finally, forms a C-C-B₄And C, combining a tread sweeper grinder.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the invention provides a C-C-B₄C, combining the tread sweeper grinder, which comprises the following components in percentage by weight: 5-10% of a binder, 10-20% of graphite, 10-25% of carbon fibers, 10-20% of copper fibers, 5-8% of boron carbide and 40-50% of iron powder, wherein the total amount of the graphite and the boron carbide is 2-5 times, preferably 3 times that of the binder, and the carbon fibers and the copper fibersThe total amount of vitamins is not more than 30%.

As a further improvement of the invention, the binding agent is Carbores P, the carbon residue content of the binding agent is more than 85%, and the binding agent is converted into a C-C binding network when being fired at high temperature. Other resin binders, such as phenolic resin, can also be converted into a C-C binding network during high-temperature firing, but the carbon residue after conversion is only 40% -70%, and the carbon binding strength can be higher by more than 85% of the carbon P binder used in the invention.

As a further improvement of the invention, the graphite is copper-plated graphite to improve the mechanical strength of the graphite.

As a further improvement of the invention, the carbon fiber adopts SIC coating carbon fiber, and the thickness of the coating is 0.35-0.4 micron, so as to solve the problem of oxidation of pure carbon fiber at 500 ℃.

As a further improvement of the invention, the boron carbide adopts 1000-mesh fine powder, so that the boron carbide is more dispersed, and in addition, the characteristic of starting oxidation at 600 ℃ is utilized, so that the boron carbide can play two roles, namely, the effect of preventing oxidation can be realized, the carbon bonding oxidation formed by Carbores P bonding agent can be prevented, the carbon bonding strength is ensured, and one of the products of the oxidation of the boron carbide is B₂O₃The material is a low-melting-point material, and the initial melting point is 445 degrees, so that the reinforcing effect can be realized.

As a further improvement of the invention, the iron powder is secondary reduced iron powder with the granularity of 100 meshes.

As a further improvement of the invention, the copper fibers are brass fibers having a copper content of greater than 55%.

The invention also provides a C-C-B₄The preparation method of the grinding element combined with the tread sweeper comprises the following steps:

(1) firstly, weighing and proportioning the raw materials, then adding the raw materials into a mixer for pre-homogenizing for 10-20 minutes, then adding an organic solvent accounting for 5-10% of the weight of the raw materials, and then granulating for 2-5 minutes to discharge, thus obtaining a primary granulation material;

(2) putting the granulated material into a drying roller for rotary secondary granulation and drying until the volatile matter is less than 1%, reducing the volatile matter and reducing the possible gas generation way to obtain a qualified mixture;

(3) placing the qualified mixture and the steel backing matched with the grinding mill into a cold pressing die, and performing cold pressing molding;

(4) placing the cold-pressed and molded semi-finished grinding mill into a curing furnace for curing;

(5) and uniformly stacking the semi-finished grinding mill millstones after the curing treatment in a stainless steel tank, sealing, and carrying out non-oxidation sintering in a sintering kiln to obtain the finished grinding mill millstones.

As a further improvement of the invention, the organic solvent in the step (1) is one or a combination of two of FF liquid (furfural), ethylene glycol and absolute ethyl alcohol; when two organic solvents are used in combination, it is necessary to have FF solution and W (FF solution): w (ethylene glycol) ═ 3: 1 or W (FF liquid): w (absolute ethyl alcohol) ═ 3: 1.5. in the actual production process, due to segregation reasons of the mixed materials, the grinding mill is easy to cause nonuniformity, the local strength of the grinding mill is easy to cause higher and local strength is easy to cause lower, and therefore the overall strength is influenced.

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

(1) C-C-B of the invention₄C, the grinding element of the tread sweeper is combined, and a carbon-carbon combination mode is adopted, so that heat fading generated in the friction process of the grinding element can be effectively avoided; boron carbide is adopted as a reinforcing auxiliary agent, can simultaneously play a role in medium-temperature reinforcement, and is combined with carbon to finally form C-C-B₄The C combination mode has stable structure and can not generate slag falling in the friction process;

(2) C-C-B of the invention₄C, the grinding element of the tread sweeper is combined, the bonding agent is completely carbonized in the production process, organic gas is not released in the using process, and the grinding element has a positive effect in the aspect of environmental protection;

(3) C-C-B of the invention₄C-combined tread sweeperThe grinding mill, the inventor obtains through a large number of tests and analyses that the total amount of graphite and boron carbide is 2-5 times, preferably 3 times, of the total amount of the binding agent, the total amount of the carbon fiber and the copper fiber is not more than 30%, under the condition that the amount of the carbon fiber and the copper fiber is certain, the synergistic effect of the graphite, the boron carbide and the binding agent is optimal, the overall bonding strength of the grinding mill is high, and when the continuous drag grinding distance of the grinding mill reaches 12000 meters, the stability of the friction coefficient is still maintained;

(4) C-C-B of the invention₄C combines the tread sweeper to grind the son, the binder is Carbores P, its carbon residue is up to more than 85%, these binders will turn into C-C and combine the network while firing at high temperature. Other resin binders, such as phenolic resin and the like, can also be converted into a C-C binding network during high-temperature firing, but the carbon residue after conversion is only 40-70 percent, and the carbon P binder adopted in the invention can ensure that the carbon binding strength is higher by more than 85 percent of the carbon residue;

(5) C-C-B of the invention₄C combines tread sweeper to grind the son, and boron carbide adopts 1000 mesh fine powder, makes it more dispersed, utilizes its characteristics that begin to oxidize at 600 degrees in addition, can play two effects, and the effect of preventing oxidation can prevent the carbon that Carbores P binder formed from combining the oxidation, guarantees carbon bonding strength, and one of the product of utilizing boron carbide self oxidation is B₂O₃The material is a low-melting-point material, and the initial melting point is 445 degrees, so that the reinforcing effect can be realized.

Drawings

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and examples, but it should be understood that these drawings are designed for illustrative purposes only and thus do not limit the scope of the present invention. Furthermore, unless otherwise indicated, the drawings are intended to be illustrative of the structural configurations described herein and are not necessarily drawn to scale.

FIG. 1 shows a schematic view of the present invention C-C-B₄C, combining a brake curve schematic diagram of the ramp of the novel grinding sub;

FIG. 2 is a schematic diagram of a conventional ramp braking curve for a grinder.

In the figure: 3. 9, pressure; 4. 10 torque; 2. 8, temperature; 1. a factor of 7; 5. 11, time; 6. 12 full coordinates correspond to: pressure 2MPa, torque 100 N.m, temperature 1000 deg.C, friction coefficient 1.0.

Detailed Description

The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration exemplary embodiments in which the invention may be practiced. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the invention, to set forth the best mode of carrying out the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the invention is to be limited only by the following claims.

The detailed description and exemplary embodiments of the invention will be better understood when read in conjunction with the appended drawings, where the elements and features of the invention are identified by reference numerals.

Example 1

The invention is illustrated below with reference to specific examples. It will be understood by those skilled in the art that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention in any way.

A C-C-B of this example₄The preparation method of the grinding element combined with the tread sweeper specifically comprises the following steps:

(1) preparing materials: the ingredients are prepared according to the following formula, the specific parameters are shown in table 3, and a scheme or automatic ingredient charging system can be adopted for the ingredients, the error of the ingredients is required to be +/-0.05 g, and the ingredients comprise the following components in percentage by weight: 8% of CARBORES P, 12% of copper-plated graphite, 20% of SiC-coated carbon fiber, 15% of 55% of copper fiber, 5% of 1000-mesh boron carbide and 40% of 100-mesh secondary reduced iron powder;

(2) mixing materials: after the raw materials are prepared according to the formula proportion, the raw materials are sequentially put into a mixer for pre-homogenization and fiber opening, and the pre-homogenization time is 600 seconds;

(3) and (3) granulation: then adding 8% of organic solvent, wherein the organic solvent comprises FF liquid (furfural) and ethylene glycol, and W (FF liquid): w (ethylene glycol) ═ 3: 1, granulating for 2 minutes, and then discharging;

(4) drying materials: putting the granulated mixture into an oven for drying treatment, wherein the drying time is 3 hours, and then detecting that the volatile matter is 0.8 percent, and obtaining qualified material when the volatile matter is less than 1 percent;

(5) cold pressing: weighing the qualified materials according to the weighing requirement, putting the weighed materials into a cold pressing die, putting a matched steel backing, and performing cyclic pressing according to the following parameters: the mold temperature is normal temperature, and the pressing curve is as follows: 0-20 MPa is 30S, 20-50 MPa is 60S, 50MPa is maintained for 150, 50-20 MPa is subjected to pressure relief for 30S to 18MPa in equal proportion, and then pressure relief is completely carried out;

(6) and (3) curing: in order to ensure the uniform curing of the product and the safety of the product, the curing is carried out in a curing oven according to a reasonable temperature rise curve, wherein the temperature is 1 hour at room temperature to 60 ℃, 3 hours at 60-90 ℃, 4 hours at 90-122 ℃, 4 hours at 122-138 ℃, 3 hours at 138-168 ℃ and 2 hours at 168-185 ℃, and then the curing chamber door can be opened after the product is naturally cooled to below 100 ℃;

(7) and (3) firing: uniformly stacking the cured product in a stainless steel tank, sealing, pushing into a sintering kiln, and heating to 1000 ℃ under an oxygen-free environment according to the following heating curve: 0.5 hour at room temperature to 300 ℃, 1 hour at 300 to 450 ℃, 5 hours at 450 to 750 ℃, 1 hour at 750 to 850 ℃, 1.5 hours at 850 to 1000 ℃, and heat preservation for 1.5 hours at 1000 ℃, then cooling to 350 ℃, opening a kiln door, and taking out the finished product of the millets after cooling to room temperature.

Comparative example 1

A method of making a tread sweeper abrasive combination according to comparative example 1 was substantially the same as in example 1 except that no boron carbide was present in the composition.

The C-C-B obtained in example 1₄C grinding the productAfter cutting, the coefficient of friction test was performed on an MM3000 Friction tester, C-C-B of FIG. 1 below₄C combined with the new mill ramp braking curve, while the comparative example 1 conventional mill was subjected to a coefficient of friction test on an MM3000 friction tester, as shown below in fig. 2 for the conventional mill ramp braking curve.

TABLE 1 this example C-C-B₄C-combined novel grinder ramp braking curve

Table 2 comparative example 1 conventional mill ramp braking curve

As can be seen by comparing Table 1 corresponding to FIG. 1 with Table 2 corresponding to FIG. 2, this embodiment C-C-B₄And C, the friction coefficient of the combined grinder is small in fluctuation amount in the whole braking process, and the friction coefficient is relatively stable.

Example 2

(1) preparing materials: the ingredients are prepared according to the following formula, the specific parameters are shown in table 3, and a scheme or automatic ingredient charging system can be adopted for the ingredients, the error of the ingredients is required to be +/-0.05 g, and the ingredients comprise the following components in percentage by weight: 5% of CARBORES P, 15% of copper-plated graphite, 15% of SiC-coated carbon fiber, 13% of 55% of copper fiber, 7% of 1000-mesh boron carbide and 45% of iron powder;

(2) mixing materials: after the raw materials are prepared according to the formula proportion, the raw materials are sequentially put into a mixer for pre-homogenization and fiber opening, and the pre-homogenization time is 900 seconds;

(3) and (3) granulation: then adding 6% of organic solvent, wherein the organic solvent comprises FF liquid (furfural) and ethylene glycol, and W (FF liquid): w (absolute ethyl alcohol) ═ 3: 1.5, granulating for 5 minutes, and then discharging;

(4) drying materials: putting the granulated mixture into an oven for drying treatment, wherein the drying time is 3 hours, and then detecting that the volatile matter is 0.9 percent, and obtaining qualified material when the volatile matter is less than 1 percent;

Example 3

(1) preparing materials: the ingredients are prepared according to the following formula, the specific parameters are shown in table 3, and a scheme or automatic ingredient charging system can be adopted for the ingredients, the error of the ingredients is required to be +/-0.05 g, and the ingredients comprise the following components in percentage by weight: 6% of CARBORES P, 18% of copper-plated graphite, 12% of SiC-coated carbon fiber, 15% of 55% of copper fiber, 6% of 1000-mesh boron carbide and 43% of iron powder;

(3) and (3) granulation: then 8% of FF liquid is added for granulation, and the granulation time is 5 minutes, and then the materials can be discharged;

(4) drying materials: putting the granulated mixture into an oven for drying treatment, wherein the drying time is 3 hours, and then detecting that the volatile matter is 0.95 percent, and obtaining qualified material when the volatile matter is less than 1 percent;

Example 4

(1) preparing materials: the ingredients are prepared according to the following formula, the specific parameters are shown in table 3, and a scheme or automatic ingredient charging system can be adopted for the ingredients, the error of the ingredients is required to be +/-0.05 g, and the ingredients comprise the following components in percentage by weight: 5% of CARBORES P, 10% of copper-plated graphite, 10% of SiC-coated carbon fiber, 20% of 55% of copper fiber, 5% of 1000-mesh boron carbide and 50% of iron powder;

(2) mixing materials: after being prepared according to the formula proportion, the raw materials are sequentially put into a mixer for pre-homogenization and fiber opening, and the pre-homogenization time is 1200 seconds;

(3) and (3) granulation: then adding 6% of organic solvent, wherein the organic solvent comprises FF liquid (furfural) and ethylene glycol, and W (FF liquid): w (absolute ethyl alcohol) ═ 3: 1.5, granulating for 4 minutes, and then discharging;

(4) drying materials: putting the granulated mixture into an oven for drying treatment, wherein the drying time is 3 hours, and then detecting that the volatile matter is 0.85 percent, and obtaining qualified material when the volatile matter is less than 1 percent;

TABLE 3 recipe parameters

Claims

1. C-C-B₄The grinding mill combined with the tread sweeper is characterized by comprising the following components in percentage by weight: 5-10% of a binder, 10-20% of graphite, 10-25% of carbon fibers, 10-20% of copper fibers, 5-8% of boron carbide and 40-50% of iron powder;

the binding agent is Carbores P; the copper fiber is brass fiber with copper content more than 55%, the total amount of graphite and boron carbide is 2-5 times of the total amount of the bonding agent, and the total amount of the carbon fiber and the copper fiber is not more than 30%;

the boron carbide is fine powder of 1000 meshes.

2. A C-C-B compound according to claim 1₄And C, combining the tread sweeper grinder, and is characterized in that the graphite is copper-plated graphite.

3. A C-C-B compound according to claim 2₄The C is combined with a tread sweeper grinder, and is characterized in that the carbon fiber is SiC coating carbon fiber, and the thickness of the coating is 0.35-0.4 microns.

4. A C-C-B compound according to claim 3₄The grinding mill is characterized in that the iron powder is secondary reduced iron powder with the granularity of 100 meshes.

5. C-C-B according to any one of claims 1 to 4₄The preparation method of the grinding element combined with the tread sweeper is characterized by comprising the following steps:

(1) weighing and proportioning the raw materials, adding the raw materials into a mixer for pre-homogenizing for 10-20 minutes, adding an organic solvent accounting for 5-10% of the weight of the raw materials, and then granulating for 2-5 minutes to discharge, thus obtaining a primary granulation material;

(2) putting the granulated material into a drying roller for rotary secondary granulation and drying until the volatile matter is less than 1 percent to obtain a qualified mixture;

6. A C-C-B compound according to claim 5₄The preparation method of the grinding mill combined with the tread sweeper is characterized in that the organic solvent in the step (1) is one or a combination of two of FF liquid, glycol and absolute ethyl alcohol; when two organic solvents are used in combination, it is necessary to have FF solution and W (FF solution): w (ethylene glycol) ═ 3: 1 or W (FF liquid): w (absolute ethyl alcohol) ═ 3: 1.5.