Metal cutting oil and preparation method thereof

Abstract

The invention particularly relates to metal cutting oil and a preparation method thereof, and belongs to the technical field of metal processing oil. The metal cutting oil provided by the invention comprises the following components in percentage by mass: 1.0-30.0% of an anti-wear reagent at extreme pressure, 0.5-3.0% of a dispersing agent, 0.5-2.0% of an antioxidant, 0.05-1.5% of a metal corrosion inhibitor, 0.5-3.0% of an anti-rust agent and the balance of base oil. The core of the metal cutting oil is that through scientific compounding and precise proportion control of the extreme pressure anti-wear agent and the dispersing agent and combined use of the metal corrosion inhibitor and the antirust agent, the oil has extremely high extreme pressure anti-wear performance and comprehensive metal protection capacity, the bearing capacity (PD value) of the metal cutting oil is larger than or equal to 3900 N, and the metal cutting oil is free of corrosion to copper, aluminum, steel and stainless steel materials.

Description

Technical Field

[0001] This invention belongs to the field of metalworking fluid technology, specifically relating to a metal cutting fluid and its preparation method. Background Technology

[0002] Metal cutting is one of the fundamental processes in mechanical manufacturing, widely used in industries such as automotive, aerospace, and precision instruments. During the cutting process, intense friction, high temperatures, and high pressures are generated between the cutting tool and the workpiece, easily leading to problems such as tool wear, decreased workpiece surface quality, loss of machining accuracy, and increased energy consumption. Therefore, cutting oil, as an important machining auxiliary medium, directly affects machining efficiency, tool life, and product quality through its lubricating, cooling, rust-preventing, and cleaning properties.

[0003] Currently, common metal cutting fluids on the market are mainly divided into two categories: oil-based cutting fluids and water-based cutting fluids. Oil-based cutting fluids typically use mineral oil as the base oil and add additives such as lubricants, extreme pressure anti-wear agents, and rust inhibitors, providing good lubrication and rust prevention. Water-based cutting fluids disperse oil in water through emulsifiers, offering excellent cooling performance. Existing patent CN119875724A discloses a metal cutting fluid and its preparation method, which uses perfluorohexanone as the core and modified silica as the shell of microparticles to simultaneously solve lubrication and oil mist problems. However, perfluorohexanone is an expensive fluoride fire extinguishing agent with a complex production process and high energy consumption, resulting in extremely high final product costs, potentially far exceeding market affordability. Furthermore, perfluorohexanone itself is a potent greenhouse gas, and its life-cycle environmental impact assessment is complex, potentially leading to environmental and safety burdens. Existing patent CN120082384A discloses an environmentally friendly metal cutting oil with high load-bearing capacity and high wear resistance. This cutting fluid is composed of diisooctyl sebacate, phosphate ester amine salt extreme pressure additives, borate additives, and sulfurized extreme pressure additives. The sulfurized extreme pressure additives are sulfurized fatty acid esters and dialkyl pentasulfides (Rc2540). This cutting oil has a load-bearing capacity (Pb) of over 920N and a wear scar diameter (Db) of less than 0.35mm under low load and long wear. However, it performs poorly in terms of cooling and cleaning properties and is prone to generating oil mist, which has adverse effects on the working environment and the health of operators.

[0004] As the manufacturing industry moves towards higher efficiency, precision, and green practices, higher demands are being placed on the performance of cutting oils. However, currently used cutting oils have poor cooling performance and are prone to oil mist generation; they also lack versatility with different metal materials, with some cutting oils unsuitable for machining copper parts and others unsuitable for machining steel parts. Therefore, developing a metal cutting oil that combines good cooling performance with strong versatility is an urgent problem to be solved in the industry. Summary of the Invention

[0005] To address the problems of poor cooling performance, limited versatility, and pollution associated with existing cutting oils, there is an urgent need to develop a new type of metal cutting oil that combines excellent lubrication, cooling, and rust prevention properties with environmental friendliness, long service life, and strong versatility. This would not only help improve the efficiency and quality of machining processes but also reduce overall costs and environmental impact.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a metal cutting oil comprising, by mass percentage, the following components: 1.0-30.0% extreme pressure anti-wear agent, 0.5-3.0% dispersant, 0.5-2.0% antioxidant, 0.05-1.5% metal corrosion inhibitor, 0.5-3.0% rust inhibitor, with the balance being base oil, and the mass ratio of the dispersant to the extreme pressure anti-wear agent being 1:1-15.

[0008] Preferably, the metal cutting oil comprises the following components by mass percentage: 5.0-10.0% extreme pressure anti-wear agent, 1.0-2.0% dispersant, 0.6-1% antioxidant, 0.1-0.3% metal corrosion inhibitor, 1.5-3.0% rust inhibitor, with the balance being base oil.

[0009] In some embodiments, the metal cutting oil comprises the following components by weight percentage: 10.0% extreme pressure anti-wear agent, 2.0% dispersant, 0.6% antioxidant, 0.2% metal corrosion inhibitor, 3.0% rust inhibitor, with the balance being base oil.

[0010] Preferably, the base oil is a paraffinic base oil or a naphthenic base oil, wherein the paraffinic base oil is selected from at least one of 10# white oil, 15# white oil, 22# white oil, and 32# white oil.

[0011] Preferably, the extreme pressure anti-wear agent is a compound of at least two of chlorinated paraffin, sulfurized fatty acid ester, sulfurized lard, sulfurized olefin, phosphate ester, and phosphite ester, and when the extreme pressure anti-wear agent is a compound of sulfurized lard and phosphate ester, the mass ratio of the two is 1-1.5:1.

[0012] Preferably, the dispersant is calcium alkyl sulfonate or calcium petroleum sulfonate; and / or, the antioxidant is a compound of 2,6-di-tert-butyl-p-cresol or alkyl diphenylamine; and / or, the metal corrosion inhibitor is a benzotriazole derivative or methylbenzotriazole; and / or, the rust inhibitor is at least one of sodium petroleum sulfonate, barium petroleum sulfonate, barium dinonylnaphthalene sulfonate, and zinc naphthenate.

[0013] The metal cutting oil provided by this invention, through the specific selection and synergistic ratio of each component, especially by controlling the mass ratio of dispersant and extreme pressure anti-wear agent, ensures the stable dispersion and efficient synergy of the additive system in the base oil, ultimately giving the product extremely high load-carrying capacity (PD value ≥ 3900N) and providing excellent anti-corrosion protection for various metal materials such as copper, aluminum, steel, and stainless steel, achieving "one oil for multiple uses" and extremely strong versatility.

[0014] Extreme pressure anti-wear agents and dispersants play a crucial synergistic role in metal cutting oils. Extreme pressure anti-wear agents primarily form a high-strength protective film on the metal surface through chemical reactions under high temperature and pressure conditions, effectively preventing direct metal-to-metal contact and frictional wear. While high-alkalinity calcium sulfonate dispersants do not primarily perform extreme pressure functions, they can form stable adsorption and oil films on the metal surface, providing good basic lubrication in the low-to-medium load range. The synergy between the two enables a load-level protection mechanism: in the low-to-medium load range, the dispersant mainly provides lubrication and oil film protection; while under high-load extreme conditions, the extreme pressure anti-wear agent rapidly intervenes, generating a robust protective film through chemical reactions, thus forming a continuous and reliable anti-wear and lubrication protection system across the entire operating range.

[0015] Furthermore, the two types of components mentioned above also exhibit significant synergistic enhancement effects in rust and corrosion prevention. During extreme pressure machining, metal surfaces are prone to localized corrosion or oxidation due to high temperature, high pressure, and potential moisture intrusion. High-basicity calcium sulfonate, with its high basicity (TBN), can effectively neutralize acidic substances generated during machining (such as moisture, air, or corrosive components introduced by the workpiece), thereby preventing metal surface corrosion. Simultaneously, this type of dispersant can also form a protective layer on the metal surface through physical or chemical adsorption, working together with extreme pressure anti-wear agents to construct a multi-layered protective system, significantly improving the overall rust-preventive performance of the cutting oil. This synergistic mechanism can effectively inhibit the corrosion of machined parts and tools, and is particularly suitable for humid environments or composite machining scenarios involving multiple metal materials, thus helping to extend the service life of tools and workpieces.

[0016] Secondly, the present invention provides a method for preparing the above-mentioned metal cutting oil, characterized by comprising the following steps:

[0017] (1) Add the base oil and antioxidant to the reaction vessel, heat to 40-50 ℃ and stir for 15-25 minutes at a stirring speed of 300-500 r / min;

[0018] (2) Add extreme pressure anti-wear agent, dispersant, metal corrosion inhibitor and rust inhibitor to the system obtained in step (1) in sequence, keep at 40-50 ℃ and continue stirring for 30-45 minutes, stirring speed is 400-600 r / min, to obtain crude product;

[0019] (3) The crude product is filtered through a microporous membrane of 0.22-0.45 μm, and the filtrate is collected to obtain the metal cutting oil.

[0020] Preferably, the order of adding the components in step (2) is as follows: first, add the extreme pressure anti-wear agent and stir for 10-15 minutes to fully disperse it; then add the dispersant and stir for 8-12 minutes to effectively coat and stabilize the extreme pressure anti-wear agent particles; finally, add the metal corrosion inhibitor and rust inhibitor simultaneously and stir for 12-18 minutes. This stepwise feeding and stirring process ensures that each functional additive can be fully dissolved, dispersed, and form a stable system, avoiding problems such as uneven composition, precipitation, or performance degradation that may be caused by simple mixing, thus ensuring the stability and reproducibility of product performance.

[0021] Thirdly, the present invention provides the application of the above-mentioned metal cutting oil in cutting, milling, stamping, rolling or drawing processes of copper, aluminum, steel and stainless steel.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) Through the scientific compounding of extreme pressure anti-wear agents and the precise control of the ratio with dispersants, the oil is given an extremely high PD value (≥3900N), which can effectively cope with extreme pressure and temperature, significantly reduce tool wear, and improve machining accuracy and surface finish.

[0024] (2) By combining metal corrosion inhibitors and rust inhibitors, it provides comprehensive protection for a variety of metal materials and prevents rusting between processes, especially effective for active metals such as aluminum and copper.

[0025] (3) A composite antioxidant system is adopted to effectively delay the oxidation and deterioration of oil products during use, extend the oil change cycle, and reduce the cost of use. While ensuring high performance, the types and amounts of additives are optimized to reduce the environmental and health hazards that may be caused by traditional chlorine-based and sulfur-based additives. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0027] Example 1

[0028] A metal cutting oil comprises the following components in weight percentages: extreme pressure anti-wear agent 2.0%; dispersant 1.5%; antioxidant 0.5%; metal corrosion inhibitor 0.05%; rust inhibitor 2.0%; base oil 93.95%.

[0029] Among them, the extreme pressure anti-wear agent is sulfurized olefin, the dispersant is calcium petroleum sulfonate, the antioxidant is 2,6-di-tert-butyl-p-cresol, the metal corrosion inhibitor is benzotriazole derivative, the rust inhibitor is sodium petroleum sulfonate, and the base oil is 32# white oil.

[0030] Example 2

[0031] A metal cutting oil comprises the following components in weight percentages: extreme pressure anti-wear agent 5.0%; dispersant 1.0%; antioxidant 0.5%; metal corrosion inhibitor 0.1%; rust inhibitor 1.5%; base oil 91.9%.

[0032] The extreme pressure anti-wear agent is 5.0% sulfurized fatty acid ester, the dispersant is calcium alkyl sulfonate, the antioxidant is 2,6-di-tert-butyl-p-cresol, the metal corrosion inhibitor is methylbenzotriazole, the rust inhibitor is barium petroleum sulfonate, and the base oil is 15# white oil.

[0033] Example 3

[0034] A metal cutting oil comprises the following components in weight percentages: 10.0% extreme pressure anti-wear agent; 2.0% dispersant; 0.6% antioxidant; 0.2% metal corrosion inhibitor; 3.0% rust inhibitor; and 84.2% base oil.

[0035] The extreme pressure anti-wear agent is 6.0% sulfurized lard and 4.0% phosphate ester, the dispersant is calcium alkyl sulfonate, the antioxidant is alkyl diphenylamine, the metal corrosion inhibitor is methylbenzotriazole, the rust inhibitor is barium dinonylnaphthalene sulfonate, and the base oil is No. 10 white oil.

[0036] Example 4

[0037] A metal cutting oil comprises the following components in weight percentages: 10.0% extreme pressure anti-wear agent; 2.0% dispersant; 0.6% antioxidant; 0.2% metal corrosion inhibitor; 3.0% rust inhibitor; and 84.2% base oil.

[0038] The extreme pressure anti-wear agent is 5.0% sulfurized lard and 5.0% phosphate ester, the dispersant is calcium alkyl sulfonate, the antioxidant is alkyl diphenylamine, the metal corrosion inhibitor is methylbenzotriazole, the rust inhibitor is barium dinonylnaphthalene sulfonate, and the base oil is No. 10 white oil.

[0039] Example 5

[0040] A metal cutting oil comprises the following components in weight percentages: extreme pressure anti-wear agent 25.0%; dispersant 2.5%; antioxidant 0.6%; metal corrosion inhibitor 0.2%; rust inhibitor 1.5%; base oil 70.2%.

[0041] The extreme pressure anti-wear agent is chlorinated paraffin, the dispersant is calcium alkyl sulfonate, the antioxidant is 2,6-di-tert-butyl-p-cresol, the metal corrosion inhibitor is benzotriazole, the rust inhibitor is zinc naphthenate, and the base oil is 22# white oil.

[0042] Comparative Example 1

[0043] A metal cutting oil comprises the following components in weight percentages: extreme pressure anti-wear agent 2.0%; antioxidant 0.5%; metal corrosion inhibitor 0.1%; rust inhibitor 1.0%; base oil 95.9%.

[0044] Among them, the extreme pressure anti-wear agent is sulfurized olefin, the antioxidant is 2,6-di-tert-butyl-p-cresol, the metal corrosion inhibitor is benzotriazole, the rust inhibitor is barium petroleum sulfonate, and the base oil is No. 10 white oil.

[0045] Comparative Example 2

[0046] A metal cutting oil comprises the following components in weight percentages: 2.5% dispersant; 0.5% antioxidant; 1.5% rust inhibitor; and 90.5% base oil.

[0047] The dispersant is calcium petroleum sulfonate, the antioxidant is alkyl diphenylamine, the rust inhibitor is barium petroleum sulfonate, and the base oil is 15# white oil.

[0048] Comparative Example 3

[0049] A metal cutting oil comprises the following components in weight percentages: 1.0% extreme pressure anti-wear agent; 2.5% dispersant; 0.5% antioxidant; 0.1% metal corrosion inhibitor; 1.0% rust inhibitor; and 95.9% base oil.

[0050] Among them, the extreme pressure anti-wear agent is sulfurized fatty acid ester, the dispersant is calcium alkyl sulfonate, the antioxidant is 2,6-di-tert-butyl-p-cresol, the metal corrosion inhibitor is methylbenzotriazole, the rust inhibitor is barium dinonylnaphthalene sulfonate, and the base oil is 32# white oil.

[0051] The preparation method of the above-mentioned metal cutting oil specifically includes the following steps:

[0052] (1) Heat and stir the base oil and antioxidant at 40-50 ℃, then add extreme pressure anti-wear agent, dispersant, metal corrosion inhibitor and rust inhibitor, mix and stir evenly to obtain crude product;

[0053] (2) The crude product is filtered to obtain metal cutting oil. Performance evaluation is performed using the cutting oil of the present invention.

[0054] Tribological performance tests were conducted using a four-ball friction and wear testing machine from Xiamen Tianji Automation Co., Ltd. The machine model was MS-10JS, with a power of 3KW. The tribological performance tests included: maximum non-seize load (PB) value and sintering load (PD) value. Specific procedures were performed according to the instruction manual of the four-ball friction and wear testing machine.

[0055] Corrosion test method: according to GB / T 6144-2010. The specific steps are as follows: Immerse the prepared test pieces (copper / aluminum / cast iron) in the metal cutting oil prepared in the above examples and comparative examples, cover with a glass cover, place in a thermostat at 55±2℃, and test continuously for 72 hours. Then take out the test pieces for inspection.

[0056] Table 1 Performance Test Results

[0057] Example PB value / kg PD value / kg Copper corrosion Aluminum sheet corrosion Corrosion of cast iron sheets Example 1 85 400 1a A A Example 2 90 500 1a A A Example 3 86 400 1a A A Example 4 84 390 1a A A Example 5 85 500 1a A A Comparative Example 1 70 315 3a A A Comparative Example 2 42 160 1a A A Comparative Example 3 54 250 1a A A

[0058] The performance test data of the prepared metal cutting oil are shown in Table 1. The PB value (≥84 kg) and PD value (≥390 kg) of all examples are much higher than those of the comparative example. This indicates that the product of the present invention can form an extremely robust lubricating film, effectively coping with extreme high pressure and high temperature conditions, thereby significantly reducing tool wear and improving machining accuracy and surface finish. Compared with Comparative Example 1, Example 1 demonstrates a synergistic effect between the extreme pressure anti-wear agent and the dispersant. The synergistic effect mechanism can be explained as follows: the dispersant, through its excellent dispersion and suspension capabilities, prevents the extreme pressure anti-wear agent molecules from agglomerating and precipitating in the oil, allowing them to be more uniformly dispersed in the oil. Under frictional high temperature and high pressure conditions, more effective active ingredients can reach the metal surface more quickly and uniformly and react to form a more robust and complete lubricating protective film, thereby significantly improving the maximum non-seize load (PB value) and sintering load (PD value) of the oil. The extreme pressure anti-wear agent content of Comparative Example 3 (low content extreme pressure agent + high content dispersant) is only 1.0%, and even with a dispersant content as high as 2.5%, its PB value is only 54 kg. This proves from the opposite perspective that the prerequisite for synergistic effect is that there must be a sufficient amount of extreme pressure anti-wear agent as the "main agent" and the dispersant is the "synergist", and it cannot be created out of thin air.

[0059] In summary, the metal cutting oil formulation technology provided by this invention, through precise component design and ratio control, especially the synergistic compounding of extreme pressure anti-wear agents and dispersants, successfully solves the technical challenge of simultaneously achieving high performance (high PB / PD value), broad-spectrum corrosion protection (suitable for various metals), and environmental friendliness (reducing chlorine and sulfur hazards).

[0060] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements or modifications should fall within the protection scope of the appended claims.

Claims

1. A metal cutting oil, characterized in that, The metal cutting oil comprises the following components by mass percentage: 1.0-30.0% extreme pressure anti-wear agent, 0.5-3.0% dispersant, 0.5-2.0% antioxidant, 0.05-1.5% metal corrosion inhibitor, 0.5-3.0% rust inhibitor, with the balance being base oil; the mass ratio of the dispersant to the extreme pressure anti-wear agent is 1:1-15; the metal cutting oil has a load-carrying capacity (PD value) ≥3900N and is non-corrosive to copper, aluminum, steel, and stainless steel.

2. The metal cutting oil according to claim 1, characterized in that, The metal cutting oil contains the following components by weight percentage: 5.0-10.0% extreme pressure anti-wear agent, 1.0-2.0% dispersant, 0.6-1% antioxidant, 0.1-0.3% metal corrosion inhibitor, 1.5-3.0% rust inhibitor, with the balance being base oil.

3. The metal cutting oil according to claim 1, characterized in that, The metal cutting oil contains the following components by weight percentage: 10.0% extreme pressure anti-wear agent, 2.0% dispersant, 0.6% antioxidant, 0.2% metal corrosion inhibitor, 3.0% rust inhibitor, with the balance being base oil.

4. The metal cutting oil according to claim 1, characterized in that, The base oil is a paraffinic base oil or a naphthenic base oil, wherein the paraffinic base oil is selected from at least one of 10# white oil, 15# white oil, 22# white oil, and 32# white oil.

5. The metal cutting oil according to claim 1, characterized in that, The extreme pressure anti-wear agent is a compound of at least two of the following: chlorinated paraffin, sulfurized fatty acid ester, sulfurized lard, sulfurized olefin, phosphate ester, and phosphite ester. When the extreme pressure anti-wear agent is a compound of sulfurized lard and phosphate ester, the mass ratio of the two is 1-1.5:

1.

6. The metal cutting oil according to claim 1, characterized in that, The dispersant is calcium alkyl sulfonate or calcium petroleum sulfonate; and / or, the antioxidant is a compound of 2,6-di-tert-butyl-p-cresol or alkyl diphenylamine; and / or, the metal corrosion inhibitor is a benzotriazole derivative or methylbenzotriazole; and / or, the rust inhibitor is at least one of sodium petroleum sulfonate, barium petroleum sulfonate, barium dinonylnaphthalene sulfonate, and zinc naphthenate.

7. The method for preparing the metal cutting oil according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Add the base oil and antioxidant to the reaction vessel, heat to 40-50 ℃ and stir for 15-25 minutes at a stirring speed of 300-500 r / min; (2) Add extreme pressure anti-wear agent, dispersant, metal corrosion inhibitor and rust inhibitor to the system obtained in step (1) in sequence, keep at 40-50 ℃ and continue stirring for 30-45 minutes, stirring speed is 400-600 r / min, to obtain crude product; (3) The crude product is filtered through a microporous membrane of 0.22-0.45 μm, and the filtrate is collected to obtain the metal cutting oil.

8. The application of the metal cutting oil according to any one of claims 1-6 in the cutting, milling, stamping, rolling or drawing processes of copper, aluminum, steel or stainless steel.