A cutting fluid, its preparation method and application

Abstract

This invention relates to a cutting fluid, its preparation method, and its application, belonging to the field of metal processing cutting technology. It solves the problem that existing cutting fluids cannot simultaneously achieve environmental friendliness, multi-metal versatility, and rust removal performance. The cutting fluid, by weight percentage, comprises 1 wt%–20 wt% glycerol polyoxyethylene ether, 0.5–5 wt% modified boric acid powder, 0.1–2 wt% magnesium hydroxysilicate, and the balance being water. The modified boric acid powder is prepared by mixing boric acid powder, anhydrous ethanol, cocoyl diethanolamide, and deionized water, stirring at 40–50°C for 6–10 hours, and finally vacuum freezing and drying at -40°C. The resulting cutting fluid achieves long-lasting and stable rust prevention, wear resistance, and lubrication effects, and can be applied to various metal materials.

Description

Technical Field

[0001] This invention relates to the field of metal cutting technology, and in particular to a cutting fluid, its preparation method, and its application. Background Technology

[0002] Metallic materials such as aluminum alloys, titanium alloys, and cast steel have a wide range of applications due to their excellent properties, especially in the aerospace field, where the requirements for surface quality and machining accuracy of parts made from metallic materials are very stringent. Therefore, during the machining process, cutting fluid is needed for cooling and lubrication of the cutting tools and parts to obtain high-quality parts.

[0003] Most existing metal cutting fluids contain elements such as sulfur, phosphorus, and halogens. On the one hand, the oxides of these elements can pollute the environment and harm human health; on the other hand, additives containing these elements are prone to decomposition during the cutting process, producing sulfides and / or chlorides, which can lead to rust on parts and machine tools, especially when machining cast iron and cast steel parts.

[0004] Currently, environmentally friendly cutting fluids (mineral-based / plant-based / synthetic processing oils free of HAPs (polycyclic aromatic hydrocarbons) and BaPs (benzo[a]pyrene) and other polycyclic aromatic hydrocarbons) do not exhibit outstanding friction-reducing, wear-resistant, or extreme-pressure-resistant properties when applied to different metals, failing to significantly improve product processing quality and incurring high costs. Therefore, there is an urgent need for a multi-metal, environmentally friendly cutting fluid. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a cutting fluid, its preparation method and application, in order to solve the problem of poor performance and versatility of existing metal cutting fluids.

[0006] On one hand, the present invention provides a cutting fluid comprising, by weight percentage, 1-20 wt% glycerol polyoxyethylene ether, 0.5-5 wt% modified boric acid powder, 0.1-2 wt% magnesium hydroxysilicate, and the balance being water;

[0007] The preparation steps of the modified boric acid powder include: mixing boric acid powder, anhydrous ethanol, cocoyl diethanolamide and deionized water, stirring at 40-50℃ for 6-10 hours, and finally obtaining the product after vacuum freezing and drying at -40℃.

[0008] Further, the glycerol polyoxyethylene ether is 5-15 wt%, the modified boric acid is 2-3.5 wt%, the magnesium hydroxysilicate is 1-2 wt%, and the balance is water.

[0009] Furthermore, the hydroxyl value of the glycerol polyoxyethylene ether is 120–290 mg KOH / g.

[0010] Furthermore, the glycerol polyoxyethylene ether is selected from G12, G18, G25 and G26.

[0011] Furthermore, the particle size of the modified boric acid is 10-50 nm.

[0012] Furthermore, the particle size of the magnesium hydroxysilicate is 20-40 nm.

[0013] Furthermore, the cutting fluid has a load-bearing capacity of over 540N.

[0014] On the other hand, the present invention provides a method for preparing a cutting fluid, comprising the following steps:

[0015] S1: Glyceryl polyoxyethylene ether is mixed with water to prepare a glyceryl polyoxyethylene ether solution;

[0016] S2: Modified boric acid and magnesium hydroxysilicate are mixed with water to prepare modified boric acid solution and magnesium hydroxysilicate solution, respectively.

[0017] S3: The cutting fluid is prepared by mixing the glycerol polyoxyethylene ether solution, the modified boric acid solution and the magnesium hydroxysilicate solution.

[0018] Furthermore, in step S3, the mixing process is carried out by heating at a temperature of 20-40°C.

[0019] Furthermore, the cutting fluid is used for machining aluminum alloy, titanium alloy, cast steel and cast iron parts.

[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0021] 1. The cutting fluid of this invention contains glycerol polyoxyethylene ether, modified boric acid, and magnesium hydroxysilicate. Through the synergistic effect of these three components, the lubrication properties of the cutting fluid under extreme pressure conditions are significantly improved, thereby ensuring the surface quality and machining accuracy of the parts. Furthermore, the cutting fluid of this invention does not contain sulfur, phosphorus, halogens, or other elements, and will not produce sulfides and / or chlorides, thus avoiding environmental pollution and any impact on machine tools or workpieces.

[0022] 2. In the cutting fluid of the present invention, modified boric acid and magnesium hydroxysilicate have good dispersion stability, uniform particle size, good surface condition, good mechanical strength and elastic modulus, which can further improve the anti-wear properties of the lubricant under extreme pressure conditions, withstand the impact of high speed and heavy load, and increase the service life and wear resistance of the lubricant.

[0023] 3. The cutting fluid preparation method in this invention is relatively simple, safe and easy to control. The resulting cutting fluid has good quality, high dispersibility and stability. Under room temperature conditions, after standing for 72 hours, the cutting fluid does not settle to the bottom.

[0024] 4. The cutting fluid provided by this invention is suitable for various machining operations such as grinding and cutting, and is suitable for machining parts of various common metals, such as aluminum alloys, titanium alloys, cast steel or cast iron parts.

[0025] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0027] Figure 1 (a) is a photograph of the cutting fluid obtained in Example 1 after it has been left to stand for 72 hours.

[0028] Figure 1 (b) is a photograph of the cutting fluid obtained in Comparative Example 3 after standing for 72 hours.

[0029] Figure 1 (c) is a photograph of the cutting fluid obtained in Comparative Example 4 after standing for 72 hours. Detailed Implementation

[0030] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0031] In the field of machining, cutting fluid is often used to lubricate and protect metal parts and tools when machining them, while also ensuring the machining quality of the metal parts.

[0032] Currently, most cutting fluids contain elements such as sulfur, phosphorus, and halogens, which not only pollute the environment and harm human health, but also cause parts and machine tools to rust, and cannot guarantee the processing quality of parts, making them unsuitable for processing parts with higher requirements.

[0033] Therefore, the present invention provides a cutting fluid comprising, by weight percentage, 1 wt% to 20 wt% glycerol polyoxyethylene ether, 0.5 to 5 wt% modified boric acid powder, 0.1 to 2 wt% magnesium hydroxysilicate, and the balance being water;

[0034] The preparation steps of the modified boric acid powder include: mixing boric acid powder, anhydrous ethanol, cocoyl diethanolamide and deionized water, stirring at 40-50℃ for 6-10 hours, and finally obtaining the product after vacuum freezing and drying at -40℃.

[0035] Compared with existing technologies, the present invention provides a cutting fluid containing glycerol polyoxyethylene ether, boric acid, and magnesium hydroxysilicate. Modified boric acid and oil polyoxyethylene ether undergo esterification reaction on the surface of the friction pair, and the resulting ammonia-containing compound can form a stable tribochemical reaction film. At the same time, as the concentration of oil polyoxyethylene ether increases, the hydroxyl groups at the ends of its molecular carbon chains can form a more stable adsorption film on the surface of the friction pair, which is not easily peeled off from the metal surface during cutting. Magnesium hydroxysilicate can form a lubrication repair film during cutting. Under the synergistic effect of the three, on the one hand, the lubrication properties of the cutting fluid under extreme pressure conditions can be significantly improved, thereby ensuring the surface quality and machining accuracy of the parts. On the other hand, the cutting fluid does not contain sulfur, phosphorus, halogens, or other elements, and will not produce sulfides and / or chlorides, thus not polluting the environment or affecting the machine tool.

[0036] This invention provides a cutting fluid suitable for various machining operations such as grinding and cutting, applicable to machining parts of various common metals, such as aluminum alloys, titanium alloys, cast steel or cast iron parts, and can inhibit the corrosive effect of water on metals to a certain extent.

[0037] In this invention, modified boric acid is used to prepare the cutting fluid. During the preparation process, boric acid is modified using cocoyl diethanolamide. First, boric acid powder is dispersed in deionized water. The nonpolar lipophilic groups of cocoyl diethanolamide adsorb onto the particle surface, while the polar hydrophilic groups are compatible with water, thus promoting the uniform dispersion of nanoparticles in water. Anhydrous ethanol acts as a promoter, accelerating the dissolution of cocoyl diethanolamide in deionized water, thereby speeding up the surface adsorption modification of the nano-boric acid powder.

[0038] Specifically, the mass ratio of boric acid powder, cocoyl diethanolamide, anhydrous ethanol and deionized water is (0.3-0.8):(1-2):(6-8):(30-40).

[0039] It should be noted that in this invention, the cutting fluid's performance is improved through the synergistic effect of glycerol polyoxyethylene ether, modified boric acid, and magnesium hydroxysilicate. In this invention, glycerol polyoxyethylene ether increases the viscosity of the cutting fluid, which helps form a lubricating adsorption film during use. When the content of glycerol polyoxyethylene ether exceeds 20 wt%, the viscosity is too high, hindering its application; when the content is below 1 wt%, a lubricating adsorption film cannot be formed effectively, resulting in poor performance.

[0040] For example, the content of the glycerol polyoxyethylene ether can be 1 wt%, 3 wt%, 5 wt%, 8 wt%, 10 wt%, 11 wt%, 13 wt%, 15 wt%, 17 wt%, 19 wt%, or 20 wt%.

[0041] Preferably, the content of the glycerol polyoxyethylene ether is 5 wt% to 15 wt%.

[0042] It should be noted that in this invention, modified boric acid can react with glycerol polyoxyethylene ether without producing sulfides and / or chlorides, thus avoiding environmental pollution and forming a stable tribochemical reaction film.

[0043] For example, the content of the modified boric acid can be 1 wt%, 1.3 wt%, 1.5 wt%, 1.85 wt%, 2.1 wt%, 2.5 wt%, 2.8 wt%, 3.7 wt%, 4.5 wt%, or 5 wt%.

[0044] Preferably, the content of the modified boric acid is 2-3.5 wt%.

[0045] It should be noted that in this invention, magnesium hydroxysilicate can form a lubricating and repairing film, while also playing a role in anti-wear and anti-corrosion, without polluting the environment or machine tools, and without affecting the workpiece.

[0046] For example, the content of the magnesium hydroxysilicate can be 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 1.85 wt%, or 2.0 wt%.

[0047] Preferably, the content of magnesium hydroxysilicate is 1-2 wt%.

[0048] Specifically, the hydroxyl value of the glycerol polyoxyethylene ether is 120-290 mgKOH / g.

[0049] Preferably, the glycerol polyoxyethylene ether is selected from G12, G18, G25 and G26.

[0050] It should be noted that in this invention, glycerol polyoxyethylene ether and modified boric acid react, and the higher the hydroxyl value of glycerol polyoxyethylene ether, the longer the carbon chain, which leads to a reduction in the wear rate and friction coefficient of the cutting fluid.

[0051] Specifically, the particle size of the modified boric acid is 10-50 nm.

[0052] Specifically, the particle size of the magnesium hydroxysilicate is 20-40 nm.

[0053] It should be noted that in this invention, the modified boric acid and the magnesium hydroxysilicate have small particle sizes, which can be embedded in the valleys of the friction pair surface during the friction test to fill the rough peaks of the wear area and play a self-repairing role; at the same time, the small particle size and high surface energy make them easy to adsorb and can replenish the adsorption film that falls off due to wear in time, thus playing an anti-wear role.

[0054] This invention provides a cutting fluid containing glycerol polyoxyethylene ether, modified boric acid, and magnesium hydroxysilicate. Under the synergistic effect of the three, the load-bearing capacity of the solution under extreme load is tested according to GB / T12583-1998 "Extreme Pressure Performance Test Method for Lubricants (Four-Ball Method)". The load-bearing capacity of the cutting fluid under load is above 540N.

[0055] This invention also provides a method for preparing a cutting fluid, comprising the following steps:

[0056] S1: Glyceryl polyoxyethylene ether is mixed with water to prepare a glyceryl polyoxyethylene ether solution;

[0057] S2: Modified boric acid powder and magnesium hydroxysilicate are mixed with water to prepare modified boric acid solution and magnesium hydroxysilicate solution, respectively.

[0058] S3: The cutting fluid is prepared by mixing the glycerol polyoxyethylene ether solution, the modified boric acid solution and the magnesium hydroxysilicate solution.

[0059] Specifically, in step S2, when preparing the modified boric acid solution and the magnesium hydroxysilicate solution, ultrasonic dispersion is used for 20-40 min, and magnetic stirring is performed at room temperature for 1-3 hours to ensure that the nanoparticles are uniformly dispersed in the solution and to avoid agglomeration that would affect the lubrication and rust prevention performance.

[0060] Specifically, in step S3, the mixing process is carried out by heating at a temperature of 20-40°C.

[0061] It should be noted that, in this invention, heating is performed during the mixing process. On the one hand, this ensures that the glycerol polyoxyethylene ether, modified boric acid, and hydroxysilicic acid are fully mixed, and also accelerates the preparation speed. On the other hand, it allows the oil polyoxyethylene ether and modified boric acid to react more completely, thereby achieving a better long-lasting and stable rust prevention, wear resistance, and lubrication effect of the cutting fluid.

[0062] The cutting fluid provided by this invention can be used for machining aluminum alloy, titanium alloy, cast steel, or cast iron parts. The cutting fluid does not contain nitrites, chlorides, or halogens, thus it is harmless to humans and the environment, and is environmentally friendly, versatile, and has excellent lubrication, cooling, and rust prevention properties.

[0063] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0064] Example 1

[0065] (1) Preparation of modified boric acid powder:

[0066] Boric acid powder, anhydrous ethanol, cocoyl diethanolamide and deionized water were mixed and stirred at 40°C for 8 hours. Finally, the mixture was vacuum-frozen and dried at -40°C to obtain modified boric acid powder. The mass ratio of boric acid powder, cocoyl diethanolamide, anhydrous ethanol and deionized water was 0.5:1.5:7:35.

[0067] (2) Preparation of cutting fluid:

[0068] S1: Glyceryl polyoxyethylene ether is mixed with water to prepare a glyceryl polyoxyethylene ether solution;

[0069] The glycerol polyoxyethylene ether is G26;

[0070] S2: Modified boric acid and magnesium hydroxysilicate are mixed with water to prepare modified boric acid solution and magnesium hydroxysilicate solution respectively; they are dispersed by ultrasonication for 30 min and magnetically stirred at room temperature for 2 h; the particle size of magnesium hydroxysilicate is 20-40 nm; the particle size of modified boric acid is 10-50 nm.

[0071] S3: The glycerol polyoxyethylene ether solution, the modified boric acid solution, and the magnesium hydroxysilicate solution are mixed at 40°C to prepare the cutting fluid.

[0072] Examples 2-5

[0073] The preparation processes of Examples 2-5 are largely the same as those of Example 1, with the differences shown in Table 1.

[0074] Table 1. Differences between Examples 2-5 and Example 1

[0075]

[0076] Comparative Example 1

[0077] This comparative example uses a sulfurized cutting fluid, brand name Pake-865.

[0078] Comparative Example 2

[0079] This comparative example uses an environmentally friendly cutting fluid, specifically the semi-synthetic coolant cutting fluid FR-806, diluted with water at a ratio of 1:20.

[0080] Comparative Example 3

[0081] The preparation process of Comparative Example 3 is largely the same as that of Example 1, except that the cutting fluid of Comparative Example 3 does not contain modified boric acid.

[0082] Comparative Example 4

[0083] The preparation process of Comparative Example 4 is largely the same as that of Example 1, except that the cutting fluid of Comparative Example 4 does not contain magnesium hydroxysilicate.

[0084] Performance testing

[0085] The cutting fluids described in Examples 1-5 and Comparative Examples 1-4 were subjected to performance testing, mainly including dispersion performance testing, wear resistance testing, and extreme pressure performance testing.

[0086] The dispersion performance test method is as follows: equal amounts of each cutting fluid are taken and placed at room temperature. After 72 hours, the sedimentation phenomenon of micro-nano particles is observed. The results are as follows. Figure 1 (a), (b), (c) and Table 2 are shown.

[0087] The wear resistance test method was as follows: friction and wear test was carried out using an MRS-10A four-ball friction and wear tester, and the analysis method was SH / T0189-1992. The rotation speed was 1000 r / min, the time was 30 min, the test load was 1500 N, and the test friction coefficient and wear scar diameter are shown in Table 2.

[0088] The extreme pressure performance test method was as follows: The load-bearing capacity of the solution under extreme load was tested according to GB / T12583-1998 "Extreme Pressure Performance Test Method for Lubricants (Four-Ball Method)". The results are shown in Table 2. The steel balls used in the test were Grade II precision GCr15 steel balls produced by Shanghai Steel Ball Factory, with a diameter of 12.7 mm and a Rockwell hardness of HRC64-66. Semi-immersion lubrication was used. The test results are shown in Table 3.

[0089] Table 2 Results of Dispersion and Wear Resistance Tests

[0090]

[0091]

[0092] Table 3 Extreme Pressure Performance Test Results

[0093] Example 1 13 993 0.48 Example 2 11 736 0.43 Example 3 12 784 0.44 Example 4 13 981 0.48 Example 5 11 623 0.39 Comparative Example 1 12 784 0.46 Comparative Example 2 12 490 0.38 Comparative Example 3 11 784 0.44 Comparative Example 4 10 511 0.38

[0094] Based on Examples 1-5 and Comparative Examples 1-4, and in conjunction with Tables 2 and 3, it can be seen that the cutting fluids obtained in Examples 1-5 have good dispersibility, virtually no sedimentation, and high wear resistance and extreme pressure performance. The wear scar diameter is 0.23-0.29 mm, and the friction coefficient is 0.029-0.030. The load-bearing capacity of the cutting fluid is above 540 N, and can even reach above 600 N.

[0095] Application examples

[0096] Example 1 and Comparative Example 1 were used for actual cutting processes, mainly including the processing of aluminum alloy, titanium alloy, cast steel and cast iron parts. The test results are shown in Table 4.

[0097] Table 4 Test Results

[0098]

[0099]

[0100] As can be seen from Table 4, the cutting fluid provided by this invention is applicable to a variety of metal materials, such as aluminum alloys, titanium alloys, cast steel and cast iron parts, ensuring the surface quality and machining accuracy of the parts, and will not affect the machine tool and the workpiece.

[0101] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A cutting fluid, characterized in that, The composition, by weight percentage, comprises 1-20 wt% glycerol polyoxyethylene ether, 0.5-5 wt% modified boric acid powder, 0.1-2 wt% magnesium hydroxysilicate, and the balance being water; the hydroxyl value of the glycerol polyoxyethylene ether is 120-290 mg KOH / g; the particle size of the modified boric acid powder is 10-50 nm; and the particle size of the magnesium hydroxysilicate is 20-40 nm. The preparation steps of the modified boric acid powder include: mixing boric acid powder, anhydrous ethanol, cocoyl diethanolamide and deionized water, stirring at 40-50℃ for 6-10 hours, and finally obtaining the product after vacuum freezing and drying at -40℃.

2. The cutting fluid according to claim 1, characterized in that, The glycerol polyoxyethylene ether is 5-15 wt%, the modified boric acid powder is 2-3.5 wt%, the magnesium hydroxysilicate is 1-2 wt%, and the balance is water.

3. The cutting fluid according to claim 1 or 2, characterized in that, The glycerol polyoxyethylene ether is selected from G12, G18, G25 and G26.

4. The cutting fluid according to claim 1, characterized in that, The cutting fluid has a load-bearing capacity of over 540N.

5. A method for preparing a cutting fluid as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Glyceryl polyoxyethylene ether is mixed with water to prepare a glyceryl polyoxyethylene ether solution; S2: Modified boric acid powder and magnesium hydroxysilicate are mixed with water to prepare modified boric acid solution and magnesium hydroxysilicate solution, respectively. S3: The cutting fluid is prepared by mixing the glycerol polyoxyethylene ether solution, the modified boric acid solution and the magnesium hydroxysilicate solution.

6. The method for preparing the cutting fluid according to claim 5, characterized in that, In step S3, the mixing process is carried out by heating at a temperature of 20-40℃.

7. An application of the cutting fluid as described in any one of claims 1-4, characterized in that, The cutting fluid is used for the cutting of aluminum alloy, titanium alloy, cast steel and cast iron parts.

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