Low-sodium high-wear-resistant white corundum and preparation process thereof

Abstract

The application provides a low-sodium high-wear-resistance white corundum and a preparation process, and belongs to the technical field of white corundum composite powder. The low-sodium high-wear-resistance white corundum comprises the following components in parts by weight: 68-72 parts of low-sodium white corundum raw powder, 8-11 parts of phenolic resin powder, 4-7 parts of modified glass fiber, 3-5 parts of heat-resistant modifier and 4-6 parts of potassium cryolite. The low-sodium high-wear-resistance white corundum is used for preparing a white corundum grinding wheel. The low-sodium high-wear-resistance white corundum can effectively improve the working efficiency and service life of the prepared white corundum grinding wheel when the low-sodium high-wear-resistance white corundum is used for preparing the white corundum grinding wheel.

Description

Technical Field

[0001] This invention belongs to the technical field of white fused alumina composite powder, specifically relating to a low-sodium, high-wear-resistant white fused alumina and its preparation process. Background Technology

[0002] White fused alumina is the main raw material for grinding wheels, and it is widely used in various industrial processes due to its high hardness and excellent grinding performance. However, due to its insufficient toughness, white fused alumina can cause abrasive grains to break during cutting, affecting work efficiency and processing quality. To address this shortcoming, resin is added as a binder when manufacturing composite white fused alumina powder. The resin binder has good elasticity and toughness, which can improve the impact resistance of white fused alumina grinding wheels to a certain extent. This makes white fused alumina grinding wheels perform excellently in high-speed and heavy-duty grinding.

[0003] However, because white fused alumina is prone to agglomeration, it cannot bond well with the resin. Furthermore, the resin has poor heat resistance and may soften or decompose at high temperatures, affecting the working efficiency and service life of the resulting grinding wheel. Summary of the Invention

[0004] To address the problems existing in the background art, the present invention provides a low-sodium, high-wear-resistant white fused alumina and its preparation process, ensuring that when the low-sodium, high-wear-resistant white fused alumina is used to prepare white fused alumina grinding wheels, it can effectively improve the working efficiency and service life of the white fused alumina grinding wheels.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a low-sodium, high-wear-resistant white fused alumina, comprising the following components by weight: 68-72 parts of low-sodium white fused alumina raw powder, 8-11 parts of phenolic resin powder, 4-7 parts of modified glass fiber, 3-5 parts of heat-resistant modifier, and 4-6 parts of potassium cryolite.

[0006] Furthermore, the modified glass fiber is prepared as follows: A1. Clean the glass fiber in the cleaning machine to obtain clean glass fiber; A2. The clean glass fiber obtained in A1 is completely immersed in concentrated nitric acid solution, and the concentrated nitric acid solution containing the clean glass fiber is placed in a constant temperature chamber for constant temperature treatment to obtain acidified glass fiber. A3. The acidified glass fiber obtained in A2 is washed with deionized water and then vacuum dried in a drying oven to obtain the modified glass fiber.

[0007] Furthermore, in A1, the glass fiber is cleaned sequentially in a KQ-100DE ultrasonic cleaner using deionized water, anhydrous ethanol, and then deionized water, with each cleaning session lasting 8-12 minutes.

[0008] Further, in A2, the mass fraction of the concentrated nitric acid solution is 62%-68%, and the mass ratio of the clean glass fiber to the concentrated nitric acid solution is 1:(40-50).

[0009] Furthermore, in A2, the isothermal treatment temperature is 75-80℃, and the isothermal treatment time is 2.5-3h.

[0010] Furthermore, in A3, the vacuum drying temperature is 57-62℃, and the vacuum drying time is 10-11h.

[0011] Furthermore, the heat-resistant modifier is MS-NB.

[0012] Furthermore, the low-sodium, high-wear-resistant white fused alumina is used to prepare white fused alumina grinding wheels.

[0013] Secondly, the present invention provides a preparation process for the above-mentioned low-sodium, high-wear-resistant white corundum, comprising the following steps: S1. Add low-sodium white corundum powder, phenolic resin powder and potassium cryolite into a mixer and mix to obtain the first mixture. S2. Add heat-resistant modifier and modified glass fiber to the first mixture obtained in S1, mix evenly to obtain the second mixture, which is the low-sodium high-wear-resistant white corundum.

[0014] Furthermore, in S1, the mixing time is 30-35 min; in S2, the mixing time is 55-60 min.

[0015] This application has the following beneficial effects: 1. The addition of modified fibers in this invention, on the one hand, forms a stronger interfacial bond with the low-sodium white fused alumina powder particles, acting as a bridge to reduce direct contact between the low-sodium white fused alumina powder particles, reduce agglomeration, promote uniform distribution of the low-sodium white fused alumina powder particles, and effectively improve the dispersion state of the low-sodium white fused alumina powder particles in the matrix.

[0016] On the other hand, modified fibers have a high melting point and strong heat resistance. They can also form thermal barriers between resins, preventing the rapid transfer of heat from the working end of the grinding wheel, thus protecting the resin from high temperatures to a certain extent. At the same time, modified glass fibers can act as a skeleton in the resin, restricting the movement of resin molecular chains at high temperatures and improving the thermal stability of the resin at high temperatures.

[0017] In this way, the two aspects work together to effectively improve the working efficiency and service life of the white fused alumina grinding wheel.

[0018] 2. The modified glass fiber of this invention is used in conjunction with the heat-resistant modifier. On the one hand, they restrict the movement of resin molecular chains through different mechanisms, and on the other hand, they inhibit the degradation process of resin at high temperature, thereby synergistically improving the heat resistance of resin.

[0019] On the other hand, the surface of the modified glass fiber is much more active than its internal structure, and can exert a strong adsorption effect on both the resin and the heat-resistant modifier at the same time. This allows the heat-resistant modifier to act more specifically on the resin and improve its heat resistance. It also weakens the effect of the heat-resistant modifier on the flowability of the grinding wheel material, avoids the grinding wheel surface from becoming too dense and smooth, and prevents the heat dissipation capacity of the grinding wheel from further decreasing.

[0020] In this way, the modified glass fiber and the heat-resistant modifier work synergistically to improve the heat resistance of the grinding wheel and effectively prevent the heat dissipation performance of the grinding wheel from further decreasing due to the addition of the heat-resistant modifier, thereby synergistically improving the working efficiency and service life of the grinding wheel. Attached Figure Description

[0021] Figure 1 A comparative trend chart of the working efficiency test data of the white corundum abrasive wheel cutting discs prepared in Examples 1-5 and Comparative Examples 1-5 in the experimental examples of this invention; Figure 2 A comparative trend chart of the service life test data of white corundum abrasive wheel cutting discs prepared in Examples 1-5 and Comparative Examples 1-5 of the present invention. Detailed Implementation

[0022] The present application will be further described in detail below with reference to the embodiments.

[0023] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0024] Example 1: (1) Preparation of modified glass fiber, the preparation method is as follows: A1. Clean the glass fiber sequentially with deionized water, anhydrous ethanol, and then deionized water in a KQ-100DE ultrasonic cleaner, with each cleaning session lasting 10 minutes, to obtain clean glass fiber.

[0025] A2. The clean glass fiber obtained in A1 is completely immersed in a concentrated nitric acid solution with a mass fraction of 65% and a mass ratio of clean glass fiber to concentrated nitric acid solution of 1:45. The concentrated nitric acid solution containing the clean glass fiber is placed in a constant temperature chamber for constant temperature treatment at 78°C for 2.8 hours. Then it is filtered to obtain acidified glass fiber.

[0026] A3. The acidified glass fiber obtained in A2 is washed with deionized water and then vacuum dried in a drying oven at a temperature of 60°C for 10.5 hours to obtain the modified glass fiber.

[0027] The glass fiber is chopped glass fiber (BX-139), grade A, 3-4.5mm, purchased from Taian Senyang Composite Materials Co., Ltd.

[0028] (2) A preparation process for low-sodium, high-wear-resistant white corundum, comprising the following steps: S1. By weight, add 70 parts of low-sodium white corundum powder, 9 parts of phenolic resin powder and 5 parts of potassium cryolite into a mixer and mix them. The mixing speed is 220 r / min and the mixing time is 32 min to obtain the first mixture.

[0029] S2. According to the same standard weight proportions, add 4 parts of heat-resistant modifier and 6 parts of modified glass fiber to the first mixture obtained in S1, and continue mixing. The mixing speed is still maintained at 220r / min, and the mixing time is 57min to obtain the second mixture, which is low-sodium high-wear-resistant white corundum.

[0030] The low-sodium white corundum raw powder was 100 mesh. Phenolic resin powder (brand name 2123) was purchased from Jinan Dahui Chemical Technology Co., Ltd. Potassium cryolite (100 mesh) was purchased from Zhengzhou Tianzhirui New Materials Co., Ltd. The heat-resistant modifier, MS-NB (brand name: Denki Kagaku, Japan), was purchased from Boruida New Materials Co., Ltd.

[0031] This low-sodium, high-wear-resistant white fused alumina is used to prepare white fused alumina grinding wheels. The specific preparation method is as follows: Add 3 parts by weight of liquid phenolic resin to the low-sodium, high-wear-resistant white fused alumina, place it in a mold and level it. After covering with the upper mold plate, push it into a press and hold it under 18 MPa pressure for 5 seconds. Release the pressure and demold to obtain the shaped blank. Place the shaped blank in a hardening furnace for hardening, starting at 60℃. The hardening temperature is increased from 60℃ to the maximum hardening temperature of 185℃ over 10 hours, and then maintained at this maximum hardening temperature for 8 hours. After hardening, slowly cool to room temperature. After unloading, a white fused alumina grinding wheel cutting disc with dimensions of 400*3.2*32 is obtained.

[0032] Example 2: The difference between this example and Example 1 is that: (1) Modified glass fiber is prepared, and the preparation method is as follows: A1. Clean the glass fiber sequentially with deionized water, anhydrous ethanol, and then deionized water in a KQ-100DE ultrasonic cleaner, with each cleaning session lasting 8 minutes, to obtain clean glass fiber.

[0033] A2. The clean glass fiber obtained in A1 is completely immersed in a concentrated nitric acid solution with a mass fraction of 62% and a mass ratio of clean glass fiber to concentrated nitric acid solution of 1:40. The concentrated nitric acid solution containing the clean glass fiber is placed in a constant temperature chamber for constant temperature treatment at 75°C for 2.5 hours. Then it is filtered to obtain acidified glass fiber.

[0034] A3. The acidified glass fiber obtained in A2 is washed with deionized water and then vacuum dried in a drying oven at a temperature of 57°C for 10 hours to obtain the modified glass fiber.

[0035] Example 3: The difference between this example and Example 1 is that: (1) Modified glass fiber is prepared, and the preparation method is as follows: A1. Clean the glass fiber sequentially with deionized water, anhydrous ethanol, and then deionized water in a KQ-100DE ultrasonic cleaner, with each cleaning session lasting 12 minutes, to obtain clean glass fiber.

[0036] A2. The clean glass fiber obtained in A1 is completely immersed in a concentrated nitric acid solution with a mass fraction of 68% and a mass ratio of clean glass fiber to concentrated nitric acid solution of 1:50. The concentrated nitric acid solution containing the clean glass fiber is placed in a constant temperature chamber for constant temperature treatment at 80°C for 3 hours. Then it is filtered to obtain acidified glass fiber.

[0037] A3. The acidified glass fiber obtained in A2 is washed with deionized water and then vacuum dried in a drying oven at a temperature of 62°C for 11 hours to obtain the modified glass fiber.

[0038] Example 4: The difference between this example and Example 1 is that: (2) A preparation process for low-sodium, high-wear-resistant white corundum includes the following steps: S1. By weight, add 68 parts of low-sodium white corundum powder, 8 parts of phenolic resin powder and 4 parts of potassium cryolite into a mixer and mix them. The mixing speed is 220 r / min and the mixing time is 30 min to obtain the first mixture.

[0039] S2. According to the same standard weight proportions, add 3 parts of heat-resistant modifier and 4 parts of modified glass fiber to the first mixture obtained in S1, and continue mixing. The mixing speed is still maintained at 220r / min, and the mixing time is 55min to obtain the second mixture, which is low-sodium high-wear-resistant white corundum.

[0040] Example 5: The difference between this example and Example 1 is that: (2) A preparation process for low-sodium, high-wear-resistant white corundum includes the following steps: S1. By weight, 72 parts of low-sodium white corundum powder, 11 parts of phenolic resin powder and 6 parts of potassium cryolite are added to a mixer and mixed at a mixing speed of 220 r / min for 35 min to obtain the first mixture.

[0041] S2. According to the same standard weight proportions, add 5 parts of heat-resistant modifier and 7 parts of modified glass fiber to the first mixture obtained in S1, and continue mixing. The mixing speed is still maintained at 220r / min, and the mixing time is 60min to obtain the second mixture, which is low-sodium high-wear-resistant white corundum.

[0042] Comparative Example 1: The difference between this comparative example and Example 1 is that the modified glass fiber and the heat-resistant modifier are removed.

[0043] Specifically, a preparation process for low-sodium, high-wear-resistant white corundum includes the following steps: S1. By weight, add 70 parts of low-sodium white corundum powder, 9 parts of phenolic resin powder and 5 parts of potassium cryolite into a mixer and mix them. The mixing speed is 220 r / min and the mixing time is 32 min to obtain the first mixture.

[0044] S2. Continue mixing the first mixture obtained in S1, keeping the mixing speed at 220 r / min and the mixing time at 57 min, to obtain the second mixture, which is low-sodium, high-wear-resistant white corundum.

[0045] Comparative Example 2: The difference between this comparative example and Example 1 is that the modified glass fiber is removed.

[0046] Specifically, a preparation process for low-sodium, high-wear-resistant white corundum includes the following steps: S1. By weight, add 70 parts of low-sodium white corundum powder, 9 parts of phenolic resin powder and 5 parts of potassium cryolite into a mixer and mix them. The mixing speed is 220 r / min and the mixing time is 32 min to obtain the first mixture.

[0047] S2. According to the same standard weight parts, add 4 parts of heat-resistant modifier to the first mixture obtained in S1, continue mixing, and keep the mixing speed at 220r / min for 57min to obtain the second mixture, which is low-sodium high-wear-resistant white corundum.

[0048] Comparative Example 3: The difference between this comparative example and Example 1 is that the heat-resistant modifier is removed and the modified glass fiber is replaced with glass fiber.

[0049] Specifically, a preparation process for low-sodium, high-wear-resistant white corundum includes the following steps: S1. By weight, add 70 parts of low-sodium white corundum powder, 9 parts of phenolic resin powder and 5 parts of potassium cryolite into a mixer and mix them. The mixing speed is 220 r / min and the mixing time is 32 min to obtain the first mixture.

[0050] S2. According to the same standard weight proportions, add 6 parts of glass fiber to the first mixture obtained in S1, continue mixing, and keep the mixing speed at 220r / min for 57min to obtain the second mixture, which is low sodium high wear-resistant white corundum.

[0051] Comparative Example 4: The difference between this comparative example and Example 1 is that the modified glass fiber is replaced with glass fiber.

[0052] Specifically, a preparation process for low-sodium, high-wear-resistant white corundum includes the following steps: S1. By weight, add 70 parts of low-sodium white corundum powder, 9 parts of phenolic resin powder and 5 parts of potassium cryolite into a mixer and mix them. The mixing speed is 220 r / min and the mixing time is 32 min to obtain the first mixture.

[0053] S2. According to the same standard weight proportions, add 4 parts of heat-resistant modifier and 6 parts of glass fiber to the first mixture obtained in S1, and continue mixing. The mixing speed is still maintained at 220r / min, and the mixing time is 57min to obtain the second mixture, which is low-sodium high-wear-resistant white corundum.

[0054] Comparative Example 5: The difference between this comparative example and Example 1 is that the heat-resistant modifier is removed.

[0055] Specifically, a preparation process for low-sodium, high-wear-resistant white corundum includes the following steps: S1. By weight, add 70 parts of low-sodium white corundum powder, 9 parts of phenolic resin powder and 5 parts of potassium cryolite into a mixer and mix them. The mixing speed is 220 r / min and the mixing time is 32 min to obtain the first mixture.

[0056] S2. According to the same standard weight parts, add 6 parts of modified glass fiber to the first mixture obtained in S1, and continue mixing. The mixing speed is still maintained at 220r / min, and the mixing time is 57min to obtain the second mixture, which is low sodium high wear-resistant white corundum.

[0057] Experimental Example: Experimental Subjects: White corundum abrasive wheel cutting discs prepared in Examples 1-5 and Comparative Examples 1-5.

[0058] Test items: ① Working efficiency; ② Service life.

[0059] Test method: Each test object (white corundum abrasive wheel cutting disc) was mounted on a high-speed cutting machine at a rotation speed of 2800 r / min and a cutting pressure of 16.46 N. The workpiece being cut was 8# (80*43*5) hot-rolled channel steel, made of Q235 steel. Working efficiency = mass of cut metal (g) / cutting time (s); a higher value indicates higher working efficiency. Service life = mass of cut metal (g) / mass of resin abrasive wheel wear (g); a higher value indicates a longer service life.

[0060] Experimental results: see Table 1.

[0061] Results Analysis: Analysis of Examples 1-5, combined with data from Table 1 and... Figures 1-2 As can be seen, the working efficiency of the white fused alumina grinding wheel prepared by the low-sodium, high-wear-resistant white fused alumina of the present invention (Examples 1-5) is as high as 2.57 (g / s) or more, and the service life is as high as 3.61 (g / g) or more. This indicates that the low-sodium, high-wear-resistant white fused alumina prepared by the present invention can effectively improve the working efficiency and service life of the prepared white fused alumina grinding wheel.

[0062] Analyze Example 1 and Comparative Examples 1-5 and combine the data in Table 1 and Figures 1-2 A comparison of Comparative Example 1 and Comparative Example 2 shows that, compared to Comparative Example 1, Comparative Example 2 added a heat-resistant modifier to its raw material components. As a result, the working efficiency of the white fused alumina grinding wheel prepared in Comparative Example 2 was 1.98 (g / s), significantly lower than the 2.17 (g / s) of Comparative Example 1; and the service life of the white fused alumina grinding wheel prepared in Comparative Example 2 was 2.71 (g / g), also significantly lower than the 3.04 (g / g) of Comparative Example 1. This indicates that simply adding the heat-resistant modifier to the raw material components leads to a decrease in the working efficiency and service life of the final white fused alumina grinding wheel, rather than an increase.

[0063] This is because the heat-resistant modifier MS-NB, in addition to improving the heat resistance of grinding wheels, also contains active maleic anhydride groups. These groups act as compatibilizers, promoting uniform mixing between different materials, reducing phase separation, and altering the flowability of the grinding wheel material. This helps the material better fill the tiny pores on the mold or grinding wheel surface during the forming process, resulting in a denser and smoother surface. A denser and smoother grinding wheel surface reduces the contact area between the surface and air, thus lowering convective heat transfer efficiency and reducing the grinding wheel's heat dissipation capacity. Since grinding wheels generate a large amount of heat during operation, if this heat cannot be dissipated in time, it will accumulate inside the grinding wheel. This not only affects the cutting performance of the grinding wheel but also accelerates wear and aging, ultimately reducing the grinding wheel's working efficiency and service life.

[0064] A comparison of Comparative Examples 1 and 3 shows that, compared to Comparative Example 1, Comparative Example 3, which added glass fiber to its raw material composition, achieved a working efficiency of 2.23 g / s for the white fused alumina grinding wheel, slightly higher than Comparative Example 1's 2.17 g / s. Furthermore, the service life of the white fused alumina grinding wheel obtained in Comparative Example 3 was 3.12 g / g, also slightly higher than Comparative Example 1's 3.04 g / g. This indicates that the addition of glass fiber to the raw material composition can improve both the working efficiency and service life of the final white fused alumina grinding wheel.

[0065] A comparison of Comparative Examples 3 and 4 shows that, compared to Comparative Example 3, Comparative Example 4 added a heat-resistant modifier to its raw material composition. As a result, the working efficiency of the white fused alumina grinding wheel prepared in Comparative Example 4 was 2.11 (g / s), lower than that of Comparative Example 3 (2.23 (g / s); and the service life of the white fused alumina grinding wheel prepared in Comparative Example 4 was 2.93 (g / g), also lower than that of Comparative Example 3 (3.12 (g / g)). This indicates that even with the addition of a heat-resistant modifier, the presence of glass fiber in the raw material composition still leads to a decrease in the working efficiency and service life of the final white fused alumina grinding wheel.

[0066] A comparison of Comparative Examples 3 and 5 shows that, compared to Comparative Example 3, Comparative Example 5, by replacing the glass fiber with the modified glass fiber of this invention in its raw material composition, achieved a working efficiency of 2.48 g / s for the white fused alumina grinding wheel, which is greater than that of Comparative Example 3 (2.23 g / s). Furthermore, the service life of the white fused alumina grinding wheel obtained in Comparative Example 5 was 3.43 g / g, which is also greater than that of Comparative Example 3 (3.12 g / g). This indicates that replacing the glass fiber with the modified glass fiber of this invention in the raw material composition can further improve the working efficiency and service life of the final white fused alumina grinding wheel.

[0067] A comparison between Comparative Example 5 and Example 1 shows that, compared to Comparative Example 5, Example 1 added a heat-resistant modifier to its raw material components. As a result, the working efficiency of the white fused alumina grinding wheel prepared in Example 1 was 2.61 (g / s), which is greater than the 2.48 (g / s) of Comparative Example 5; and the service life of the white fused alumina grinding wheel prepared in Example 1 was 3.66 (g / g), which is also greater than the 3.43 (g / g) of Comparative Example 5. This indicates that when modified glass fiber is present in the raw material components, the addition of a heat-resistant modifier can produce a synergistic effect, thereby synergistically improving the working efficiency and service life of the final white fused alumina grinding wheel.

[0068] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0069] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A low-sodium, high-wear-resistant white corundum, characterized in that, By weight, it includes the following raw materials: 68-72 parts of low-sodium white corundum powder, 8-11 parts of phenolic resin powder, 4-7 parts of modified glass fiber, 3-5 parts of heat-resistant modifier, and 4-6 parts of potassium cryolite. The modified glass fiber is prepared as follows: A1. Clean the glass fiber in the cleaning machine to obtain clean glass fiber; A2. The clean glass fiber obtained in A1 is completely immersed in concentrated nitric acid solution, and the concentrated nitric acid solution containing the clean glass fiber is placed in a constant temperature chamber for constant temperature treatment to obtain acidified glass fiber. A3. The acidified glass fiber obtained in A2 is washed with deionized water and then vacuum dried in a drying oven to obtain the modified glass fiber. The heat-resistant modifier is MS-NB.

2. The low-sodium, high-wear-resistant white corundum according to claim 1, characterized in that, In A1, the glass fiber was cleaned in a KQ-100DE ultrasonic cleaner using deionized water, anhydrous ethanol, and then deionized water in sequence, with each cleaning session lasting 8-12 minutes.

3. The low-sodium, high-wear-resistant white corundum according to claim 1, characterized in that, In A2, the mass fraction of the concentrated nitric acid solution is 62%-68%, and the mass ratio of the clean glass fiber to the concentrated nitric acid solution is 1:(40-50).

4. The low-sodium, high-wear-resistant white corundum according to claim 1, characterized in that, In A2, the temperature for constant temperature treatment is 75-80℃, and the treatment time is 2.5-3h.

5. The low-sodium, high-wear-resistant white corundum according to claim 1, characterized in that, In A3, the vacuum drying temperature is 57-62℃ and the vacuum drying time is 10-11h.

6. The low-sodium, high-wear-resistant white corundum according to claim 1, characterized in that, The low-sodium, high-wear-resistant white fused alumina is used to prepare white fused alumina grinding wheels.

7. A preparation process for low-sodium, high-wear-resistant white corundum as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Add low-sodium white corundum powder, phenolic resin powder and potassium cryolite into a mixer and mix to obtain the first mixture. S2. Add heat-resistant modifier and modified glass fiber to the first mixture obtained in S1, mix evenly to obtain the second mixture, which is the low-sodium high-wear-resistant white corundum.

8. The preparation process of low-sodium, high-wear-resistant white corundum according to claim 7, characterized in that, In S1, the mixing time is 30-35 min; in S2, the mixing time is 55-60 min.

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