Self-lubricating composite filler for resin-based grinding wheel and preparation method thereof

Abstract

The application discloses a kind of resin-based grinding wheel self-lubricating composite fillers and preparation method thereof, filler includes binder, reinforcing filler, lubricant and fiber material, binder includes liquid resin binder and powder resin binder.Firstly, each raw material is dryed, reinforcing filler, lubricant, fiber material is surface modified, then each raw material is mixed.For liquid resin binder, directly stirring and mixing uniformly to obtain solidification mixture;For powder resin binder, after each raw material is mixed and ball milled, solidification mixture is obtained;Solidification mixture is solidified and formed under corresponding solidification condition, and molding block is obtained, and after crushing and sieving, filler particle is obtained, and coupling modification and / or surface metal layer plating treatment is carried out, and self-lubricating composite filler is obtained.The application is used as filler to prepare grinding wheel, can play the role of lubrication and friction reduction, so as to reduce grinding temperature, improve workpiece surface quality, prolong the service life of grinding wheel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of grinding wheel manufacturing, in particular to a self-lubricating composite filler for resin-based grinding wheels and a preparation method thereof. BACKGROUND

[0002] Grinding is a machining method that removes material from the surface of a workpiece using a grinding wheel. It is often used as the final shaping process for workpieces. During grinding, the abrasive grains cut the workpiece at a large negative rake angle, generating a large amount of grinding heat at the interface between the abrasive grains and the workpiece surface. This heat can cause thermal damage to the workpiece surface, such as burning, tensile residual stress, phase transformation, and surface oxidation, which can reduce the reliability and safety of the ground workpiece in service. Therefore, controlling the grinding heat during grinding is an important means to improve the surface quality of ground workpieces.

[0003] Cooling and lubrication are the main technical means to reduce grinding heat. By spraying cooling fluid and grinding fluid onto the grinding wheel / workpiece interface in real time, the grinding heat can be effectively reduced, and the surface quality of the workpiece can be improved. However, due to the high linear speed of the grinding wheel during grinding, the centrifugal force causes a "gas barrier" effect on the surface of the grinding wheel, making it difficult for the cooling / lubricating fluid to enter the contact area between the abrasive grains and the workpiece. At the same time, the high temperature in the contact area between the abrasive grains and the workpiece can cause the cooling / lubricating fluid to vaporize instantaneously, thus failing to effectively lubricate the contact area between the abrasive grains and the workpiece. In view of this, researchers in this field have added solid lubricants (such as graphite and molybdenum disulfide) in the form of fillers to the grinding wheel formulation during the preparation of the grinding wheel, which are directly formed into the grinding wheel. During grinding, the solid lubricants are released and play a lubricating role in the contact area as the binder wears. Although this method can effectively reduce the grinding heat, the solid lubricants have low shear strength and low surface energy, making it difficult for them to be infiltrated by the resin. Therefore, excessive solid lubricants will significantly reduce the strength and wear resistance of the grinding wheel. Some scholars have also used pre-bonding to bond solid lubricants into larger self-lubricating blocks, and placed the blocks in the grinding wheel matrix to improve the contact state between the grinding wheel and the workpiece surface by wear of the blocks. However, the implantation of the blocks changes the macrostructure of the grinding wheel, and the poor adhesion between the blocks and the grinding wheel matrix leads to a decrease in the strength of the grinding wheel and an increase in the difficulty of adjusting the dynamic balance of the grinding wheel. In summary, the existing lubrication methods in the field of grinding have many drawbacks. In addition, the development of self-lubricating and high-wear-resistant grinding wheels is particularly important for dry grinding fields that do not have the conditions to spray cooling fluid and grinding fluid, such as rail grinding and rough grinding. SUMMARY

[0004] The present application aims at solving the above-mentioned problems in the prior art, and provides a self-lubricating composite filler for resin-based grinding wheels and a preparation method thereof, so as to reduce the grinding heat during the grinding process of the resin-based grinding wheels (especially in dry grinding conditions), improve the surface quality of workpieces, and further realize the preparation of self-lubricating, high-wear-resistant and long-life grinding wheels and the high-precision and low-damage processing and forming of workpieces.

[0005] The technical scheme for solving the above-mentioned technical problems is as follows:

[0006] A self-lubricating composite filler for resin-based grinding wheels, characterized in that the raw materials of the self-lubricating composite filler include, by weight, 50-70 parts of a bonding agent, 10-25 parts of a reinforcing filler, 10-35 parts of a lubricant, and 2-10 parts of a fiber material, wherein the bonding agent includes a liquid resin bonding agent and a powder resin bonding agent.

[0007] Further, the liquid resin bonding agent is epoxy resin liquid, and the powder resin bonding agent is one of phenolic resin powder, polyimide resin powder and polyether ether ketone powder. The bonding agent mainly functions to bond the reinforcing filler, the lubricant and the fiber, so as to ensure that the self-lubricating composite filler has a certain strength.

[0008] Most preferably, the bonding agent is preferably epoxy resin liquid.

[0009] Further, the reinforcing filler is one or a combination of precipitated barium sulfate, cryolite, quartz powder, corundum powder, iron oxide powder, feldspar powder and calcium carbonate powder. The reinforcing filler is used to improve the density and strength, toughness and other mechanical properties of the self-lubricating filler.

[0010] Most preferably, the reinforcing filler is a combination of precipitated barium sulfate, cryolite and calcium carbonate.

[0011] Further, the lubricant is one or a combination of graphite powder, molybdenum disulfide powder, tungsten sulfide powder and hexagonal boron nitride powder.

[0012] Most preferably, the lubricant is preferably a combination of molybdenum disulfide powder and tungsten sulfide powder.

[0013] Further, the solid lubricant can be released on the surface of the grinding wheel / workpiece contact area along with the wear of the grinding wheel binder, so as to lubricate the grinding wheel / workpiece contact area in real time, reduce the grinding heat, reduce the grinding temperature, and further reduce the thermal damage to the surface of the workpiece.

[0014] Further, the fiber is one or more combinations of aramid fiber, carbon fiber, basalt fiber, glass fiber, potassium titanate whisker. The fiber can improve the overall mechanical properties of the self-lubricating composite filler, so that the addition amount of the lubricant can be increased, and the lubricating effect of the self-lubricating composite filler can be further improved; at the same time, after the mechanical crushing of the self-lubricating composite filler, the fiber remaining on the surface of the self-lubricating filler can form an "anchoring" with the resin in the grinding wheel matrix, thereby improving the bonding strength of the self-lubricating composite filler and the resin binder, and further improving the overall mechanical properties of the resin-based grinding wheel.

[0015] Most preferably, the fiber is a combination of aramid fiber and basalt fiber.

[0016] Further preferably, the phenolic resin powder, polyimide resin powder, and polyether ether ketone powder have a particle size of 100 mesh or more.

[0017] Further preferably, the precipitated barium sulfate, cryolite, quartz powder, corundum powder, iron oxide powder, feldspar powder, and calcium carbonate powder in the reinforcing filler all have a particle size of 200 mesh or more.

[0018] Further preferably, the graphite powder, molybdenum disulfide powder, tungsten sulfide powder, and hexagonal boron nitride powder in the lubricant all have a particle size of 100 mesh or more.

[0019] Further preferably, the aramid fiber, carbon fiber, basalt fiber, glass fiber, and potassium titanate whisker in the fiber all have a diameter of 10-50 μm and a length of 0.8-3 mm.

[0020] Further preferably, the reinforcing filler, lubricant, and fiber are all surface-modified with a 2-5% silane coupling agent alcohol solution, and are dried and ball-milled for dispersion.

[0021] Further preferably, the self-lubricating composite filler for resin-based grinding wheels is optimized in the following proportions: 60-70 parts by weight of adhesive, 10-20 parts by weight of reinforcing filler, 10-20 parts by weight of lubricant, and 5-8 parts by weight of fiber material.

[0022] Further preferably, the self-lubricating composite filler for resin-based grinding wheels is optimized in the following proportions: 65 parts by weight of adhesive, 20 parts by weight of reinforcing filler, 15 parts by weight of lubricant, and 7 parts by weight of fiber material.

[0023] Further, in the preferred embodiment of the present application, the reinforcing filler, lubricant, and fiber are all surface-modified with a 2-5% silane coupling agent alcohol solution, and are dried and ball-milled for dispersion.

[0024] The present application also protects a method for preparing a self-lubricating composite filler for resin-based grinding wheels, comprising the following steps:

[0025] (1) Raw material pretreatment

[0026] (11) The reinforcing filler, lubricant, and fiber are respectively subjected to drying treatment by using a drying oven.

[0027] (12) The dried reinforcing filler, lubricant, and fiber are respectively subjected to modification treatment by using a silane coupling agent.

[0028] (13) The modified reinforcing filler, lubricant, and fiber are reserved after being ball milled.

[0029] (2) Mixing

[0030] The resin binder is mixed with the reinforcing filler, lubricant, and fiber.

[0031] For a liquid resin binder, the reinforcing filler, lubricant, and fiber are added and stirred to obtain a mixture to be cured.

[0032] For a powder resin binder, the reinforcing filler, lubricant, and fiber are mixed and ball milled to obtain a mixture to be cured.

[0033] (3) Molding

[0034] The mixture to be cured is subjected to curing molding under curing conditions to obtain a block-shaped self-lubricating composite filler.

[0035] (4) Composite filler shaping

[0036] The block-shaped self-lubricating composite filler is mechanically broken and sieved to obtain self-lubricating composite filler particles with uniform particle size.

[0037] (5) Surface treatment

[0038] The self-lubricating composite filler particles are subjected to surface coupling modification treatment and / or surface metal layer plating treatment to obtain a self-lubricating composite filler for resin-based grinding wheels.

[0039] Preferably, in step (11), drying is performed by using a drying oven, and the drying conditions are as follows: drying at 50-60°C for 20-30 h.

[0040] Preferably, in step (12), the modification method is as follows: the reinforcing filler, lubricant, and fiber are respectively placed in a 2-5 wt% silane coupling agent alcohol solution, and ultrasonic treatment is performed for 1-1.5 h under ultrasonic conditions while continuously stirring; in step (13), the corresponding reinforcing filler, lubricant, and fiber are first dried at 40-50°C for 40-50 h before ball milling, the ball mill rotates at a speed of 280-350 rpm, and the ball-to-material ratio is 1:0.6.

[0041] Preferably, in step (2), for the epoxy resin liquid as the liquid resin binder, the mixing process comprises:

[0042] (211) The epoxy resin liquid is diluted with anhydrous ethanol as the diluent, the weight of anhydrous ethanol is 10-20wt% of the epoxy resin liquid; the stirring paddle speed is 300-700rpm during the dilution process, and the stirring time is 2-5min;

[0043] (212) The lubricant is added into the diluted epoxy resin in multiple times, and the stirring paddle is used to stir at a speed of 1500-2500rpm for 10-30min;

[0044] (213) The fiber is added into the diluted epoxy resin in the above (212), and stirred at a speed of 1500-2500rpm for 5-15min;

[0045] (214) The epoxy resin curing agent is weighed, and the weight ratio of the curing agent to the epoxy resin liquid is 0.8-1.2; the curing agent is diluted with anhydrous ethanol as the diluent, and the weight of anhydrous ethanol is 10-20wt% of the epoxy resin liquid; the stirring paddle speed is 300-700rpm during the dilution process, and the stirring time is 2-5min;

[0046] (215) The diluted curing agent in the above (214) is added into the epoxy resin liquid in (213), and the stirring parameters in the above (214) are maintained for continuous stirring;

[0047] (216) The reinforcing filler is weighed and added into the mixed resin in the above (214), the stirring paddle speed is 1500-2500rpm, and the stirring time is 10-15min, to obtain the mixed material to be cured;

[0048] For the resin binder in powder state, the mixing process is as follows:

[0049] (221) The reinforcing filler is placed in a ball mill for ball milling mixing, the ball mill speed is 350-420rpm, the ball-to-material ratio is 3:1, and the ball milling time is 0.5-1h, to obtain the mixed reinforcing filler;

[0050] (222) The fiber material is mixed with the reinforcing filler in the above (221) in a ball mill, the ball mill speed is 350-420rpm, the ball-to-material ratio is 4:1, and the ball milling time is 1-2h;

[0051] (223) The lubricant is dispersed with the mixture of the mixed reinforcing filler and the fiber in (222) in a ball mill, the ball mill speed is 350-420rpm, the ball-to-material ratio is 3:1, and the ball milling time is 0.5-1h;

[0052] (224)The powder resin binder is combined with the reinforcing filler, fiber and lubricant composition obtained in step (223) and dispersed in a ball mill at a speed of 200-250 rpm, a ball-to-material ratio of 1:1 and a ball milling time of 10-15 min to obtain a mixture to be cured.

[0053] Preferably, in step (2), the mixture to be cured is cured by injecting the epoxy resin liquid into a mold and curing at 50-60°C for 48-55 h to obtain the block-shaped self-lubricating composite filler.

[0054] Preferably, in step (3), the mixture is formed by injecting the mixture into a mold and pre-pressing at 170-250°C and 5-10 MPa for 40-60 min, and then demolding to obtain the self-lubricating composite filler preform.

[0055] The self-lubricating composite filler preform is further cured in a blast drying oven at 170-250°C for 30-40 h to obtain the block-shaped self-lubricating composite filler.

[0056] Preferably, in step (5), the surface metal layer is plated by low-temperature chemical nickel plating or copper plating.

[0057] Compared with the prior art, the present application has the following advantages:

[0058] (1) The solid lubricant is bonded and mechanically broken to prepare the self-lubricating composite filler. The surface of the broken self-lubricating composite filler is chemically plated, and the surface is irregular and has a large number of protruding fibers, which can be anchored with the resin bond of the grinding wheel, thereby increasing the bonding strength of the composite filler and the resin grinding wheel matrix. By this method, the lubricant is added to the grinding wheel, which does not significantly weaken the strength and wear resistance of the grinding wheel.

[0059] (2) The resin-based self-lubricating composite filler prepared in the present application can be released in real time in the grinding wheel / workpiece contact area during the grinding process, thereby lubricating the contact area, reducing the generation of grinding heat, reducing the thermal damage of the grinding heat to the workpiece, and improving the surface processing quality of the workpiece.

[0060] (3) The use of a grinding wheel filled with self-lubricating composite filler can reduce or even replace the use of cooling / lubricating liquid which has pollution to the environment, while reducing the cost of grinding processing, thereby promoting the development of green manufacturing.

[0061] In summary, the self-lubricating composite filler for resin-based grinding wheel prepared by the present application has high compressive strength and can release in situ in the grinding wheel / workpiece contact area during the grinding process along with the wear of the grinding wheel binder, thereby playing the roles of lubrication and friction reduction, reducing the grinding temperature, improving the workpiece surface quality, and prolonging the service life of the grinding wheel. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 is a process flow chart of the preparation of the self-lubricating composite filler of Example 1 of the present application. Figure 1

[0063] Figure 3 is a process flow chart of the preparation of the self-lubricating composite filler of Example 3 of the present application. Figure 2

[0064] Figure 5 is a scanning electron microscope morphology chart of the self-lubricating composite filler prepared in Example 1 of the present application. Figure 3

[0065] Figure 7 is a curve chart of the friction coefficient of the grinding wheel / rail interface during the grinding process of the rail grinding wheel prepared in Example 6, Comparative Example 7, and Comparative Example 8 of the present application. Figure 4 DETAILED DESCRIPTION

[0066] The principles and characteristics of the present application are described below in conjunction with the examples in order to facilitate the understanding of the present application by those skilled in the art. However, it should be clear that the present application is not limited in the scope of the specific embodiments, and for those skilled in the art, any changes that are obvious within the spirit and scope of the present application as defined and determined by the appended claims are all included in the protection of the present application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturers are used. The reagents or instruments not specified by the manufacturers are all conventional products that can be purchased on the market.

[0067] Example 1

[0068] The self-lubricating composite filler for resin-based grinding wheel of the present embodiment comprises, by weight parts, 70 parts of epoxy resin liquid, 5 parts of precipitated barium sulfate, 3 parts of ice crystal stone, 2 parts of quartz powder, 5 parts of corundum powder, 20 parts of graphite powder, and 4 parts of carbon fiber.

[0069] The preparation method of the self-lubricating composite filler for resin-based grinding wheel of the present embodiment comprises:

[0070] (1) Pretreatment of raw materials

[0071] (11) The precipitated barium sulfate, ice crystal stone, quartz powder, corundum powder, graphite powder, and carbon fiber are respectively placed in a blast drying oven and baked at 50°C for 30h for drying treatment.

[0072] ​​​​(12) The precipitated barium sulfate, cryolite, quartz powder, corundum powder, graphite powder, carbon fiber were respectively placed in 3wt% silane coupling agent alcohol solution, treated for 1.5h under ultrasonic environment, and continuously stirred.

[0073] (13) The precipitated barium sulfate, cryolite, quartz powder, corundum powder, graphite powder, carbon fiber after ultrasonic treatment were respectively placed in 50℃ environment and dried for 45h.

[0074] (14) The precipitated barium sulfate, cryolite, quartz powder, corundum powder, graphite powder, carbon fiber obtained in the above (13) were respectively placed in a ball mill for ball milling dispersion, the ball mill speed was 300rpm, and the ball-to-material ratio was 1:0.6.

[0075] (2) Mixing

[0076] (21) The precipitated barium sulfate, cryolite, quartz powder, corundum powder were mixed and dispersed in a ball mill to obtain a mixed reinforcing filler.

[0077] (22) The epoxy resin liquid heated in a 50℃ oven for 10h was weighed, and anhydrous ethanol was used as a diluent to dilute the epoxy resin liquid under stirring conditions. The weight of anhydrous ethanol was 20wt% of the epoxy resin liquid. The stirring paddle speed was 500rpm, and the stirring time was 3min.

[0078] (23) The graphite powder was added to the diluted epoxy resin in three times, and a stirring paddle was used to stir at a speed of 2000rpm for 20min.

[0079] (24) The carbon fiber was weighed and added to the epoxy resin liquid in the above (23), and stirred at a speed of 2000rpm for 10min.

[0080] (25) The epoxy resin curing agent was weighed, and the weight ratio of curing agent to epoxy resin was 1:1. The curing agent was diluted with anhydrous ethanol as a diluent, and the weight of anhydrous ethanol was 20wt% of the curing agent. A stirring paddle was used for stirring during the dilution process, the stirring paddle speed was 500rpm, and the stirring time was 3min.

[0081] (26) The diluted curing agent in the above (25) was added to the epoxy resin liquid in (24), and the stirring speed was kept at 2000rpm.

[0082] (27) The reinforcing filler mixed by the ball mill in the above (21) was weighed and added to the resin liquid in the above (26) in three times, and stirred for 10min, the stirring paddle speed was 2000rpm, and the epoxy resin molding material was obtained.

[0083] (3) Molding

[0084] (31) The epoxy resin liquid molding material obtained in the above (27) is injected into a molding mold and heated in an oven;

[0085] (32) Further, the epoxy resin liquid molding curing temperature in the above (31) is 60°C, and the curing time is 50h, to obtain a block-shaped self-lubricating composite filler;

[0086] (4) Self-lubricating composite filler shaping

[0087] (41) The block-shaped self-lubricating composite filler after molding in the above (3) is mechanically broken to obtain a granular self-lubricating composite filler;

[0088] (42) The self-lubricating composite filler in the above (41) is sieved according to the requirements of the grinding wheel molding.

[0089] (5) Self-lubricating composite filler surface treatment

[0090] (51) The surface of the sieved granular self-lubricating composite filler in the above (42) is treated by low-temperature chemical copper plating to obtain a self-lubricating composite filler for resin-based grinding wheels.

[0091] Example 2:

[0092] The self-lubricating composite filler for resin-based grinding wheels of the present embodiment comprises, by weight parts, 65 parts of epoxy resin liquid, 3 parts of precipitated barium sulfate, 7 parts of corundum powder, 2 parts of iron oxide powder, 1 part of feldspar powder, 2 parts of calcium carbonate, 30 parts of tungsten sulfide powder, and 6 parts of basalt fiber.

[0093] The preparation method of the self-lubricating composite filler for resin-based grinding wheels of the present embodiment comprises:

[0094] (1) Raw material pretreatment

[0095] (11) The precipitated barium sulfate, corundum powder, iron oxide powder, feldspar powder, calcium carbonate, tungsten sulfide, and basalt fiber in the present embodiment are all sequentially subjected to drying, surface coupling agent modification, and ball milling dispersion treatment.

[0096] (2) Mixing

[0097] (21) The precipitated barium sulfate, corundum powder, iron oxide powder, feldspar powder, and calcium carbonate are mixed and dispersed in a ball mill to obtain a mixed reinforcing filler.

[0098] (22) The epoxy resin liquid is diluted with anhydrous ethanol as a diluent under stirring, and the weight of anhydrous ethanol accounts for 15wt% of the epoxy resin; the stirring paddle speed is 500rpm, and the stirring time is 3min.

[0099] (23) The tungsten sulfide powder is added into the diluted epoxy resin in three times and stirred by a stirring paddle at a speed of 2000 rpm for 20 min.

[0100] (24) The basalt fiber is weighed and added into the epoxy resin liquid in (23) above and stirred at a speed of 2000 rpm for 10 min.

[0101] (25) The epoxy resin curing agent is weighed, and the weight ratio of the curing agent to the epoxy resin liquid is 0.8:1; the curing agent is diluted by using anhydrous ethanol as a diluent, and the weight of the anhydrous ethanol is 15% of the weight of the curing agent; the stirring paddle is used for stirring during the dilution process, the stirring speed of the stirring paddle is 500 rpm, and the stirring time is 5 min.

[0102] (26) The diluted curing agent in (25) above is added into the epoxy resin liquid in (24), and the stirring speed is kept at 2000 rpm.

[0103] (27) The reinforcing filler mixed by the ball mill in (21) above is weighed and added into the mixed resin in (26) above in four times, and stirred for 10 min at a stirring paddle speed of 2000 rpm to obtain an epoxy resin molding material.

[0104] (3) Raw material molding

[0105] (31) The epoxy resin liquid molding material obtained in (27) above is injected into a molding mold and placed in an oven for heating.

[0106] (32) Further, the epoxy resin liquid molding curing temperature in (31) above is 50°C, and the curing time is 60 h to obtain a block-shaped self-lubricating composite filler.

[0107] (4) Self-lubricating composite filler shaping

[0108] (41) The block-shaped self-lubricating composite filler molded in (3) is mechanically broken to obtain a granular self-lubricating composite filler;

[0109] (42) The self-lubricating composite filler in (41) is sieved to obtain a self-lubricating composite filler with a certain particle size.

[0110] (5) Self-lubricating composite filler surface treatment

[0111] (51) The granular self-lubricating composite filler sieved in (42) is subjected to low-temperature chemical copper plating treatment on the surface to obtain a self-lubricating composite filler for resin-based grinding wheels.

[0112] Example 3:

[0113] The self-lubricating composite filler for resin-based grinding wheels of the embodiment comprises, by weight parts, phenolic resin powder 58 parts, precipitated barium sulfate 2 parts, ice crystal 1 part, quartz powder 2 parts, iron oxide powder 2 parts, calcium carbonate powder 2 parts, hexagonal boron nitride 25 parts, and glass fiber 5 parts.

[0114] The preparation method of the self-lubricating composite filler for resin-based grinding wheels of the embodiment comprises:

[0115] (1) Raw material pretreatment

[0116] (11) The phenolic resin powder and the precipitated barium sulfate, ice crystal, quartz powder, iron oxide powder, calcium carbonate powder, hexagonal boron nitride, and glass fiber are respectively placed in a blast drying oven and baked at 60°C for 25 hours.

[0117] (12) The precipitated barium sulfate, ice crystal, quartz powder, iron oxide powder, calcium carbonate powder, hexagonal boron nitride, and glass fiber are respectively placed in a 3wt% silane coupling agent alcohol solution and treated under ultrasonic environment for 1 hour with constant stirring.

[0118] (13) The precipitated barium sulfate, ice crystal, quartz powder, iron oxide powder, calcium carbonate powder, hexagonal boron nitride, and glass fiber after ultrasonic treatment are respectively dried at 50°C for 45 hours to obtain the coupling agent modified reinforcing filler, lubricant, and fiber.

[0119] (14) The precipitated barium sulfate, ice crystal, quartz powder, iron oxide powder, calcium carbonate powder, hexagonal boron nitride, and glass fiber obtained in the above (13) are respectively placed in a ball mill for ball milling and dispersion, the ball mill speed is 350 rpm, and the ball-to-material ratio is 1:0.6.

[0120] (2) Mixing

[0121] (21) The precipitated barium sulfate, ice crystal, quartz powder, iron oxide powder, and calcium carbonate powder in (14) are weighed and placed in a ball mill for ball milling and mixing, the ball mill speed is 420 rpm, the ball-to-material ratio is 3:1, and the ball milling time is 1 hour to obtain the mixed reinforcing filler.

[0122] (22) The glass fiber in (14) is weighed and mixed with the mixed reinforcing filler in the above (21) in a ball mill, the ball mill speed is 420 rpm, the ball-to-material ratio is 4:1, and the ball milling time is 2 hours.

[0123] (23) The hexagonal boron nitride is weighed and dispersed with the mixture of the mixed reinforcing filler and fiber in the above (22) in a ball mill, the ball mill speed is 400 rpm, the ball-to-material ratio is 3:1, and the ball milling time is 0.8 hours.

[0124] (24) The phenolic resin powder is weighed and combined with the precipitated barium sulfate, cryolite, quartz powder, iron oxide powder, calcium carbonate powder, glass fiber, and hexagonal boron nitride composition obtained in (23) above in a ball mill at a rotation speed of 250 rpm, a ball-to-material ratio of 1:1, and a ball milling time of 10 min. After ball milling, the mixture is sieved using a 50-mesh screen to obtain a molding material.

[0125] (3) Molding

[0126] (31) The molding material in (24) is placed in a mold and subjected to hot-press molding.

[0127] (32) The hot-pressing temperature in (31) is 180°C, the molding pressure is 10 MPa, and the pressure holding time is 60 min. After pre-press molding, the mold is opened to obtain a self-lubricating composite filler preform.

[0128] (33) The self-lubricating composite filler preform obtained in (33) is further solidified in a forced air drying oven at a solidification temperature of 180°C for a solidification duration of 40 h. After solidification is complete, a block-shaped self-lubricating composite filler is obtained.

[0129] (4) Self-lubricating composite filler shaping

[0130] (41) The block-shaped self-lubricating composite filler after molding in (33) is subjected to mechanical crushing to obtain a granular self-lubricating composite filler.

[0131] (42) The self-lubricating composite filler in (41) is sieved according to the requirements of the grinding wheel molding to obtain a granular self-lubricating composite filler with uniform size.

[0132] (5) Self-lubricating composite filler surface treatment

[0133] (51) The granular self-lubricating composite filler after sieving in (42) is subjected to low-temperature chemical copper plating treatment on the surface to obtain a self-lubricating composite filler for resin-based grinding wheels.

[0134] Example 4:

[0135] The self-lubricating composite filler for resin-based grinding wheels and the method for preparing the same in this example are the same as in Example 1, except that the formulation of the self-lubricating composite filler for resin-based grinding wheels is different.

[0136] The self-lubricating composite filler for resin-based grinding wheels in this example includes, by weight fraction, 65 parts of epoxy resin liquid, 4 parts of precipitated barium sulfate, 4 parts of cryolite, 5 parts of iron oxide powder, 25 parts of fluorite powder, 20 parts of molybdenum disulfide, and 10 parts of potassium titanate whiskers.

[0137] Example 5:

[0138] The resin-based grinding wheel self-lubricating composite filler and the preparation method thereof of the present embodiment are the same as those of Example 3, except that the resin-based grinding wheel self-lubricating composite filler formulation is different.

[0139] 65 parts of phenolic resin powder, 3 parts of precipitated barium sulfate, 3 parts of ice crystal, 1 part of calcium carbonate powder, 35 parts of fluorite, and 6 parts of glass fiber by weight.

[0140] Example 6

[0141] The self-lubricating composite filler obtained in Example 1 is used to prepare a rail grinding wheel. The raw materials of the rail grinding wheel include: 60 parts of zirconia alumina, 40 parts of brown corundum, 20 parts of phenolic resin powder, 10 parts of phenolic resin liquid, 5 parts of ice crystal, 4 parts of limestone, 3 parts of pyrite powder, 3 parts of glass fiber, and 20 parts of self-lubricating composite filler particles by weight. The particle size of the zirconia alumina and brown corundum is F14-F16, and the particle size of the self-lubricating composite filler particles is F20-F24.

[0142] The preparation method of the rail grinding wheel of the present embodiment comprises:

[0143] (1) Mixing

[0144] (11) The zirconia alumina and brown corundum are added to a double-pot countercurrent mixer for mixing, and the mixing time is 2 min, to obtain a mixed abrasive;

[0145] (12) The phenolic resin liquid is added to the mixed abrasive in the above (11) and mixed thoroughly, and the mixing time is 3 min, to obtain a wetted abrasive;

[0146] (13) The ice crystal, limestone, pyrite powder, and glass fiber are added to the wetted abrasive in the above (12) and thoroughly stirred in the upper pot of the double-pot countercurrent mixer, and the mixing time is 5 min. After mixing is completed, the mixed material is transferred to the lower pot;

[0147] (14) The phenolic resin powder and self-lubricating composite filler particles are added to the lower pot of the double-pot countercurrent mixer and mixed thoroughly with the mixed material in (13), and the mixing time is 2 min, to obtain a material to be shaped;

[0148] (15) The material to be shaped in the above (14) is passed through a 30-mesh sieve to remove excess powder, to obtain a sieve residue;

[0149] (16) The sieve residue (sieve residue) in the above (15) is passed through a 10-mesh sieve to obtain a sieve underproduct with uniform particle size and no caking, which is a rail grinding wheel shaping material;

[0150] (2) Pre-shaping

[0151] The molding material in the above (16) is weighed and delivered into a grinding wheel mold, and is pressed to form a rail grinding wheel blank under the condition of 50 DEG C and 10 MPa;

[0152] (3) Curing

[0153] The rail grinding wheel blank obtained in the above (2) is placed in a blast drying phase to cure, so that the phenolic resin of the grinding wheel is fully crosslinked. The curing process is 2 h under the condition of 50 DEG C, 5 h under the condition of 120 DEG C, 25 h under the condition of 185 DEG C, and then the furnace is cooled down, so that the rail grinding wheel is obtained.

[0154] Comparative Example 7:

[0155] The rail grinding wheel preparation method of the present comparative example is the same as that of Example 6, except that the self-lubricating composite filler is not contained in the rail grinding wheel formula, but the graphite powder is added as a self-lubricating component.

[0156] In terms of weight parts, zircon corundum 60 parts, brown corundum 40 parts, phenolic resin powder 20 parts, resin liquid 10 parts, ice crystal 5 parts, limestone 4 parts, pyrite powder 3 parts, glass fiber 3 parts, and graphite powder 4 parts. The particle size of the graphite powder is 100 mesh or more.

[0157] Comparative Example 8:

[0158] The rail grinding wheel preparation method of the present comparative example is the same as that of Example 6, except that the self-lubricating composite filler is not contained in the rail grinding wheel formula.

[0159] In terms of weight parts, zircon corundum 60 parts, brown corundum 40 parts, phenolic resin powder 20 parts, resin liquid 10 parts, ice crystal 5 parts, limestone 4 parts, pyrite powder 3 parts, and glass fiber 3 parts.

[0160] The self-lubricating composite filler for the resin-based grinding wheel obtained in the above Examples 1-5 is subjected to compression strength and tribological property detection, so that the performance detection results of the self-lubricating composite filler for the resin-based grinding wheel of the above Examples are obtained, as shown in Table 1.

[0161] Table 1 Performance detection results of the self-lubricating composite filler for the resin-based grinding wheel

[0162]

[0163] It can be obviously seen from the above results that the self-lubricating composite filler for the resin-based grinding wheel prepared by the present application has high compression strength, meets the high forming pressure requirement in the grinding wheel forming process, and can ensure that the grinding wheel has high mechanical properties after being formed.

[0164] The resin-based grinding wheel is applied with the self-lubricating composite filler to detect the tribological performance of the corundum-steel rail pair interface. The results show that the self-lubricating composite filler prepared by the application can effectively reduce the friction coefficient of the corundum-steel rail interface, thereby reducing the grinding temperature, improving the workpiece surface quality, and effectively improving the excessive wear of the resin-based grinding wheel caused by the grinding heat, thereby prolonging the service life of the grinding wheel.

[0165] The self-lubricating composite filler obtained in Example 1 is observed by scanning electron microscopy, and the surface scanning electron microscopy morphology diagram of Example 1 is shown in Figure 3 The results show that a large number of fibers protrude from the surface of the self-lubricating composite filler, which can be effectively anchored with the resin binder in the grinding wheel, thereby improving the bonding strength of the self-lubricating composite filler and the resin-based grinding wheel, and further ensuring that the grinding wheel has good mechanical properties.

[0166] The steel rail grinding wheel prepared in Example 6, Comparative Example 7 and Comparative Example 8 is subjected to compression strength detection and grinding performance detection, and the results are shown in Table 2. The results show that the use of the self-lubricating composite filler can maintain a high compression strength of the grinding wheel. Meanwhile, in the process of steel rail grinding, the self-lubricating filler in the grinding wheel can effectively lubricate the grinding wheel / steel rail interface under dry grinding conditions, thereby significantly reducing the friction coefficient of the grinding wheel / steel rail interface and the grinding heat. Under the condition of lower grinding temperature, the wear of the grinding wheel is reduced, and the grinding ratio is significantly increased. The above test results show that the addition of the self-lubricating composite filler can ensure that the grinding wheel has a high compression strength, and can effectively lubricate the grinding wheel / steel rail interface, thereby reducing the generation of grinding heat, prolonging the service life of the grinding wheel, and improving the surface quality of the steel rail.

[0167] Table 2 Performance detection results of the steel rail grinding wheel of Example 6 and Comparative Example 7

[0168]

[0169] The friction coefficient curve of the grinding wheel / steel rail interface in the process of grinding the steel rail grinding wheel prepared in Example 6, Comparative Example 7 and Comparative Example 8 is shown in Figure 4 The results show that the self-lubricating composite filler prepared in Example 1 can effectively lubricate and reduce friction of the grinding wheel / steel rail interface, reduce the friction coefficient of the grinding wheel / steel rail interface, thereby reducing the grinding heat and grinding temperature, and improving the surface quality of the workpiece. Further, it is proved that the self-lubricating composite filler particles prepared by the application have good lubricating and friction-reducing effect on the grinding wheel / workpiece interface.

[0170] Although the specific embodiments of the application have been described in detail, that should not be understood as a limitation on the scope of the patent. Various modifications and equivalents can be employed without departing from the scope of the application described in the claims.

Claims

1. A method for preparing a self-lubricating composite filler for resin bond grinding wheels, characterized by: The raw materials of the self-lubricating composite filler include: 50-70 parts by weight of a binder, 10-25 parts by weight of a reinforcing filler, 10-35 parts by weight of a lubricant, and 2-10 parts by weight of a fiber, wherein the binder is a liquid resin binder or a powder resin binder; The liquid resin binder is an epoxy resin liquid, and the powder resin binder is one of a phenolic resin powder, a polyimide resin powder, and a polyether ether ketone powder; The reinforcing filler is one or a combination of more than one of precipitated barium sulfate, cryolite, quartz powder, corundum powder, iron oxide powder, feldspar powder, and calcium carbonate powder, and has a particle size of 100 mesh or more; The lubricant is one or a combination of more than one of graphite powder, molybdenum disulfide powder, tungsten sulfide powder, and hexagonal boron nitride powder, and has a particle size of 100 mesh or more; The fiber is one or a combination of more than one of aramid fiber, carbon fiber, basalt fiber, glass fiber, and potassium titanate whisker, has a diameter of 10-50 μm, and has a length of 0.8-3 mm; The preparation method includes the following steps: (1) Raw material pretreatment (11) The reinforcing filler, the lubricant, and the fiber are respectively subjected to drying treatment by drying oven; (12) The dried reinforcing filler, the lubricant, and the fiber are respectively subjected to modification treatment by using a silane coupling agent; (13) The modified reinforcing filler, the lubricant, and the fiber are reserved after ball milling; (2) Mixing The resin binder is mixed with the reinforcing filler, the lubricant, and the fiber; For the liquid resin binder, the reinforcing filler, the lubricant, and the fiber are stirred and mixed uniformly after being added, to obtain a to-be-cured mixture; For the powder resin binder, the reinforcing filler, the lubricant, and the fiber are mixed and subjected to ball milling treatment, to obtain a to-be-cured mixture; (3) Molding The to-be-cured mixture is subjected to curing molding under curing conditions, to obtain a block-shaped self-lubricating composite filler; (4) Composite filler shaping The block-shaped self-lubricating composite filler is subjected to mechanical crushing and sieving, to obtain self-lubricating composite filler particles with uniform particle size; (5) Surface treatment The self-lubricating composite filler particles are subjected to surface coupling modification treatment and / or surface metal layer plating treatment, to obtain a self-lubricating composite filler for resin-based grinding wheels.

2. The method of claim 1, wherein the self-lubricating composite filler for resin bond grinding wheels is characterized by: In step (11), drying is performed by using a drying oven, and the drying conditions are as follows: drying at 50-60 °C for 20-30 h.

3. The method of claim 1, wherein the self-lubricating composite filler for resin bond grinding wheels is characterized by: In step (12), the modification method is as follows: the reinforcing filler, the lubricant, and the fiber are respectively placed in a 2-5 wt% silane coupling agent alcohol solution, and are subjected to ultrasonic treatment in an ultrasonic environment for 1-1.5 h, and stirring is continuously performed during the ultrasonic treatment; in step (13), the corresponding reinforcing filler, the lubricant, and the fiber are dried at 40-50 °C for 40-50 h before ball milling, the rotation speed of the ball mill is 280-350 rpm, and the ball-to-material ratio is 1:0.

6.

4. The method for preparing the self-lubricating composite filler for resin-based grinding wheels according to claim 1, characterized in that: In step (2), for the binder being an epoxy resin liquid as the liquid resin binder, the mixing process includes the following steps: (211) Anhydrous ethanol is used as a diluent to dilute the epoxy resin liquid, and the weight of the anhydrous ethanol is 10-20 wt% of the epoxy resin liquid; the stirring paddle rotation speed is 300-700 rpm during the dilution, and the stirring time is 2-5 min; (212) Add the lubricant into the diluted epoxy resin liquid in several times, and stir with the stirring paddle at a speed of 1500-2500 rpm for 10-30 min; (213) Add the fiber into the diluted epoxy resin liquid in (212), and stir at a speed of 1500-2500 rpm for 5-15 min; (214) Weigh the epoxy resin curing agent, and the weight ratio of the curing agent to the epoxy resin liquid is 0.8-1.2; dilute the curing agent with anhydrous ethanol as the diluent, and the weight of the anhydrous ethanol is 10-20 wt% of the epoxy resin liquid; during the dilution process, the stirring paddle rotates at a speed of 300-700 rpm, and the stirring time is 2-5 min; (215) Add the diluted curing agent in (214) into the epoxy resin liquid in (213), and continue to stir under the stirring parameters in (214); (216) Weigh the reinforcing filler, and add it into the mixed resin in (214), and stir at a speed of 1500-2500 rpm for 10-15 min to obtain the mixture to be cured; For the binder being a powder-state resin binder, the mixing process is as follows: (221) Put the reinforcing filler into a ball mill for ball milling mixing, the ball mill rotates at a speed of 350-420 rpm, the ball-to-material ratio is 3:1, and the ball milling time is 0.5-1 h to obtain the mixed reinforcing filler; (222) Mix the fiber material with the reinforcing filler in (221) in a ball mill, the ball mill rotates at a speed of 350-420 rpm, the ball-to-material ratio is 4:1, and the ball milling time is 1-2 h; (223) Disperse the lubricant with the mixture of the mixed reinforcing filler and the fiber in (222) in a ball mill, the ball mill rotates at a speed of 350-420 rpm, the ball-to-material ratio is 3:1, and the ball milling time is 0.5-1 h; (224) Weigh the powder-state resin binder, and disperse it with the reinforcing filler, the fiber, and the lubricant composition obtained in (223) in a ball mill, the ball mill rotates at a speed of 200-250 rpm, the ball-to-material ratio is 1:1, and the ball milling time is 10-15 min to obtain the mixture to be cured.

5. The method for preparing the self-lubricating composite filler for resin-based grinding wheels according to claim 4, characterized in that: In step (2), for the binder being an epoxy resin liquid, the curing method of the mixture to be cured is as follows: inject the epoxy resin liquid molding material into a molding mold, and cure it at 50-60℃ for 48-55 h to obtain the block-shaped self-lubricating composite filler; For the binder being a powder-state resin binder, the molding method of the mixture is as follows: put the molding material into a mold, and pre-press it into shape under the conditions of 170-250℃ and 5-10 MPa, and the pressure holding time during the pressing process is 40-60 min; after the pre-pressing, demold to obtain the self-lubricating composite filler preform; place the self-lubricating composite filler preform in an air-drying oven for further curing, the curing temperature is 170-250℃, and the curing duration is 30-40 h to obtain the block-shaped self-lubricating composite filler.

Images