Lubricating grease for engineering steel friction pair interface and preparation method thereof

Abstract

The invention belongs to the technical field of lubricants, and particularly relates to lubricating grease for an engineering steel friction pair interface and a preparation method.The lubricating grease is formed by mixing and doping a liquid lubricant and a thickening agent according to a certain proportion, firstly, the thickening agent is modified with an organic modifier through a solvent treatment method, and then the liquid lubricant and the thickening agent are mixed; and the modified thickening agent and the liquid lubricant are subjected to thickening. The lubricating grease with extremely low and even zero wear performance can be prepared, the limitation of traditional solid lubricating and liquid lubricating materials is overcome, the excellent low wear performance is shown, and a new solution is provided for solving the wear problem. Meanwhile, the method is environment-friendly and energy-saving, and is expected to play an important role in reducing energy consumption and reducing environmental pollution.

Description

Technical Field

[0001] The present invention belongs to the technical field of lubricants, and particularly relates to a grease for the interface of engineering steel friction pairs and a preparation method thereof. Background Art

[0002] Wear is a common problem in mechanical systems, resulting in huge energy consumption, economic losses and safety hazards. According to statistics, about 80% of mechanical failures globally are caused by wear. To address this challenge, it is crucial to develop materials with ultra-low or zero wear characteristics.

[0003] Lubricating materials are the key to addressing this challenge, mainly divided into two categories: solids and liquids. Solid lubricants, such as molybdenum disulfide, tungsten disulfide, graphene, and coatings, etc., need to be in a special environment (such as high vacuum, inert atmosphere, dry conditions, etc.) to exhibit excellent lubrication performance and achieve extremely low wear. At the same time, due to the inability to replenish the material in a timely manner during the friction process, significant wear may occur. And solid lubricating materials usually require a cumbersome preparation process, which limits their practicality. In contrast, liquid lubricants, including mineral oils, synthetic oils, animal and vegetable oils, and water-based liquids, etc., although widely used, are prone to problems such as volatilization, creep, and leakage. To solve the above problems, people have gradually paid attention to semi-solid lubricating materials, such as gels and greases. However, the current methods for preparing gels and greases are complex and cumbersome, requiring energy-consuming steps such as heating. Later, a solid-liquid composite lubricating system was proposed, but the compatibility of solid-liquid lubricants is also a huge challenge for researchers. Summary of the Invention

[0004] The present invention discloses a grease for the interface of engineering steel friction pairs and a preparation method thereof, which can prepare a grease with extremely low or even zero wear performance. The present invention overcomes the limitations of traditional solid lubrication and liquid lubrication materials, exhibits excellent low wear performance, and provides a new solution for solving the wear problem. At the same time, the present invention is environmentally friendly and energy-saving, and is expected to play an important role in reducing energy consumption and environmental pollution.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A grease for the interface of engineering steel friction pairs, wherein the grease is prepared by mixing and doping a liquid lubricant and a thickener in a certain proportion. First, the thickener is modified by an organic modifier through a solvent treatment method, and then the modified thickener is thickened with the liquid lubricant.

[0007] Preferably, the liquid lubricant refers to at least one of polyalphaolefin, silicone oil, vegetable oil, mineral oil, guar acid, lactic acid, sorbitan trioleate, and pentaerythritol oleate.

[0008] Preferably, the organic modifier refers to at least one of oleic acid, linoleic acid, linolenic acid, and ricinoleic acid.

[0009] Preferably, the thickener refers to one of polytetrafluoroethylene powder, nano-silica, and graphene thickener.

[0010] Preferably, the organic modifier modifies the thickener by the solvent treatment method. The solvent is anhydrous ethanol, and the mass ratio of the organic modifier, thickener, and anhydrous ethanol is between 0.1:1:10 and 0.5:1:20.

[0011] Preferably, the mass ratio of the modified thickener to the liquid lubricant is between 1:0.5 and 1:5.

[0012] A preparation method of a grease for the interface of an engineering steel friction pair includes the following steps: First, select at least one organic modifier, and use the solvent treatment method to modify the thickener. Dissolve the selected organic modifier in anhydrous ethanol, then add the thickener for modification. If two or more organic modifiers are selected, they need to be stirred and mixed first, and then the thickener is modified by the above method. Heat in an oven at 40 - 60 °C to remove anhydrous ethanol, and then mix the modified thickener into the liquid lubricant according to a certain ratio, and then stir and mix to obtain the grease for the interface of the engineering steel friction pair.

[0013] Preferably, when stirring two or more organic modifiers or liquid lubricants, a magnetic stirrer is used, and the rotation speed is 100 - 800 rpm; when mixing the liquid lubricant and the thickener, a magnetic stirrer is also used, and the rotation speed is 100 - 800 rpm.

[0014] The beneficial effects of a grease for the interface of an engineering steel friction pair and its preparation method according to the present invention are as follows:

[0015] The liquid lubricating material adopted in the present invention has the risks of flowing, creeping, and leaking during actual use, and may cause lubrication failure of the friction pair due to loss during the friction process. To overcome these problems, a thickener is selected and solidified through appropriate proportioning to form a grease. The preparation process is simple and only requires stirring at room temperature to complete. By this method, problems such as the flow and leakage of the liquid lubricant can be easily solved. In addition, the grease developed in the present invention has many advantages. First, the preparation method is simple and easy to implement, and the operation is convenient. By simply increasing the proportion, large-scale preparation can be achieved. Second, this lubricating material has excellent anti-friction and anti-wear properties, can achieve almost zero wear, and significantly extends the service life of the friction pair. Most importantly, this research expands the application field of semi-solid lubricating materials and provides more solutions to problems such as the leakage of liquid lubricants.

[0016] In summary, the present invention has the following advantages:

[0017] 1. The synthesis method is simple: It only needs to be mixed and stirred at room temperature, without steps consuming resources such as heating, and there is no cumbersome synthesis process. 2. Green and environmentally friendly: The energy consumption is greatly reduced through physical thickening. 3. The material source is wide: The price is low and it can be prepared in large quantities. 4. The material has excellent lubrication performance: The friction coefficient is low and nearly zero wear can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a diagram of the liquid lubricant, thickener and grease provided by the present invention, where 1 is the liquid lubricant, 2 is the thickener, and 3 is the grease;

[0019] Figure 2 It is a rheological curve diagram of the grease provided in Example 11, and the curves of G’ and G” changing with the shear stress at a frequency of 1 Hz;

[0020] Figure 3 It is a curve diagram of the friction coefficient of the grease provided in Example 12 changing with time;

[0021] Figure 4 It is a light microscope image of the wear scar of the grease provided in Example 12;

[0022] Figure 5 It is a curve diagram of the friction coefficient of the grease provided in Example 13 changing with time;

[0023] Figure 6 It is a light microscope image of the wear scar of the grease provided in Example 13. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following description is only for the preferred embodiments of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0025] The following embodiments can be understood as separately expressing a part of the local structure or method of the present invention, or can also be understood as the embodiments combined with each other to explain the connotation of the structure or method of a larger scope of the present invention.

[0026] Example 1

[0027] A grease for the interface of engineering steel friction pairs, which is prepared by mixing and doping a liquid lubricant and a thickener in a certain proportion. First, the thickener is modified by an organic modifier through a solvent treatment method, and then the modified thickener is thickened with the liquid lubricant.

[0028] Example 2

[0029] This example gives the specific implementation manners of the liquid lubricant, and its implementation manners include the following 8 kinds from (S11) to (S18):

[0030] (S11) Polyalphaolefin; (S12) Silicone oil; (S13) Vegetable oil; (S14) Mineral oil; (S15) Guar acid; (S16) Lactic acid; (S17) Sorbitan trioleate; (S18) Pentaerythritol oleate.

[0031] It can be understood that the user can choose one of them or use a mixture of multiple liquid lubricants.

[0032] Example 3

[0033] This example gives the specific implementation manners of the organic modifier, specifically including: the organic modifier refers to at least one of (a1) oleic acid, (a2) linoleic acid, (a3) linolenic acid, and (a4) ricinoleic acid, and the user can choose one of them or a mixture of multiple organic modifiers according to needs. (a1)-(a4) are the implementation manner numbers.

[0034] Example 4

[0035] This example gives the specific implementation manners of the thickener, and its implementation manners include the following 3 kinds: (S21), (S22), and (S23):

[0036] (S21) Polytetrafluoroethylene powder; (S22) Nano-silica, (S23) Graphene thickener. It can be understood that the user can choose one of them, which is modified by the organic modifier and then mixed and stirred with the liquid lubricant to prepare the grease.

[0037] Example 5

[0038] Based on Examples 1-4, this example discloses that: the organic modifier modifies the thickener by the solvent treatment method, the solvent is absolute ethanol, and the mass ratio of the organic modifier, the thickener, and absolute ethanol is 0.1:1:10.

[0039] Example 6

[0040] Based on Examples 1-4, this example discloses that: the organic modifier modifies the thickener by the solvent treatment method, the solvent is absolute ethanol, and the mass ratio of the organic modifier, the thickener, and absolute ethanol is 0.5:1:20.

[0041] Example 7

[0042] Based on Examples 5 and 6, this example discloses that: the mass ratio of the modified thickener to the liquid lubricant is 1:0.5.

[0043] Example 8

[0044] Based on Examples 5 and 6, this example discloses that the mass ratio of the modified thickener to the liquid lubricant is 1:5.

[0045] Example 9

[0046] Based on the above examples, this example discloses a method for preparing a grease for the interface of an engineering steel friction pair, including the following steps: First, select at least one organic modifier, and modify the thickener by the solvent treatment method. Dissolve the selected organic modifier in absolute ethanol, then add the thickener for modification. If two or more organic modifiers are selected, they need to be stirred and mixed first, and then the thickener is modified by the above method. Heat in an oven at 40°C to remove absolute ethanol, and then mix the modified thickener into the liquid lubricant in a certain proportion, and then stir and mix to obtain the grease for the interface of the engineering steel friction pair; when stirring two or more organic modifiers or liquid lubricants, a magnetic stirrer is used, and the rotation speed is 100 rpm; when mixing the liquid lubricant and the thickener, a magnetic stirrer is also used, and the rotation speed is 100 rpm.

[0047] Example 10

[0048] Based on the above examples, this example discloses a method for preparing a grease for the interface of an engineering steel friction pair, including the following steps: First, select at least one organic modifier, and modify the thickener by the solvent treatment method. Dissolve the selected organic modifier in absolute ethanol, then add the thickener for modification. If two or more organic modifiers are selected, they need to be stirred and mixed first, and then the thickener is modified by the above method. Heat in an oven at 60°C to remove absolute ethanol, and then mix the modified thickener into the liquid lubricant in a certain proportion, and then stir and mix to obtain the grease for the interface of the engineering steel friction pair; when stirring two or more liquid lubricants, a magnetic stirrer is used, and the rotation speed is 800 rpm; when mixing the liquid lubricant and the thickener, a magnetic stirrer is also used, and the rotation speed is 800 rpm.

[0049] Example 11

[0050] Add 1 g of polytetrafluoroethylene powder thickener modified with linoleic acid to 1 g of sorbitan trioleate. The mass ratio of the thickener to the liquid lubricant is 1:1. Then stir the mixed sample with a magnetic stirrer (200 rpm) for 30 min to make it evenly mixed, and a green and environmentally friendly grease is obtained, as shown in Figure 1.

[0051] The rheological properties were tested using a rotational rheometer (MCR302, Anton Paar, Austria). All tests were performed using a rotor-plate combination with a cone angle of 1°, a plate diameter of 25 mm, and a distance of 0.104 mm between the rotor and the cone plate. Before the yield point, the storage modulus (G') of the lubricant was greater than the loss modulus (G"), indicating that the elasticity of the grease was greater than its viscosity, which directly proved again that the synthesized sample existed in the form of grease.

[0052] Example 12

[0053] First, 2 g of oleic acid and 2 g of ricinoleic acid liquid lubricants were stirred using magnetic stirring at a speed of 300 rpm for 10 minutes; 2 g of nano-silica graphene thickener was added to the above mixed solution, and 10 g of anhydrous ethanol was added for modification. The modified thickener was mixed with poly-α-olefin 10 at a mass ratio of 1:0.5, and then the mixed sample was stirred (300 rpm) for 1 h to make it uniformly mixed, thus obtaining a grease.

[0054] Specifically, the friction performance was tested using the reciprocating mode of a friction and wear tester (TRB, Anton Paar). The upper friction pair was a GGr15 steel ball with a diameter of 6 mm, and the lower friction pair was a 9Gr18 steel block. Before the experiment, the friction pairs needed to be ultrasonically treated in an ethanol and acetone solution for 30 minutes, then rinsed with deionized water, and finally dried in an oven. The test load was 3 N, the frequency was 3 Hz, and the amplitude was 2 mm. The variation of the friction coefficient of the liquid lubricant used in this example between steel and steel with time is as Figure 2 shown. It can be found from Figure 2 that the running-in period of this grease is extremely short, and the friction coefficient quickly decreases to around 0.05 and remains stable. As Figure 4 shown, after 1 hour of friction, the wear scar on the surface of the steel block still remains shallow, showing near-zero wear characteristics.

[0055] Example 13

[0056] 1 g of stearic acid thickener modified with oleic acid was added to 5 g of linoleic acid liquid lubricant, where the mass ratio of the thickener to the liquid lubricant was 1:5. Then the mixed sample was stirred (300 rpm) for 1 h to make the two uniformly mixed, thus obtaining a grease.

[0057] Specifically, the reciprocating mode of a tribometer (TRB, Anton Paar) was used to test the friction performance. The upper friction pair was a GGr15 steel ball with a diameter of 6 mm, and the lower friction pair was a 9Gr18 steel block. Before the experiment, the friction pairs needed to be ultrasonically treated in an ethanol and acetone solution for 30 minutes, then rinsed with deionized water, and finally dried in an oven. The test load was 3 N, the frequency was 3 Hz, and the amplitude was 2 mm. The variation of the friction coefficient of the liquid lubricant used in this example between steel and steel with time is as Figure 5 shown. It can be found from the figure that as the friction progresses, the friction coefficient of this grease gradually decreases and finally remains near 0.04. After 3 h of long-term friction, the wear scar is also extremely shallow, and near-zero wear can also be achieved (as Figure 6 shown).

Claims

1. A lubricating grease for the interface of an engineering steel friction pair, characterized by: The grease is prepared by mixing a liquid lubricant and a thickener in a certain proportion. The thickener is first modified by an organic modifier through a solvent treatment method, and the modified thickener is then thickened with the liquid lubricant.

2. The lubricating grease for the friction pair interface of engineering steel as claimed in claim 1, characterized in that: The liquid lubricant is at least one of polyalphaolefin, silicone oil, vegetable oil, mineral oil, guar acid, lactic acid, sorbitan trioleate, and pentaerythritol oleate.

3. The lubricating grease for the friction pair interface of engineering steel as claimed in claim 2, characterized in that: The organic modifier is at least one of oleic acid, linoleic acid, linolenic acid and ricinoleic acid.

4. The lubricating grease for the friction pair interface of engineering steel as claimed in claim 3, characterized in that: The thickener is one of polytetrafluoroethylene powder, nano silicon dioxide and graphene thickener.

5. The lubricating grease for the friction pair interface of engineering steel as claimed in claim 4, characterized in that: The organic modifier modifies the thickener by a solvent treatment method, the solvent is anhydrous ethanol, and the mass ratio of the organic modifier, the thickener and the anhydrous ethanol is between 0.1:1:10 and 0.5:1:

20.

6. The lubricating grease for the friction pair interface of engineering steel as claimed in claim 5, characterized in that: The mass ratio of the modified thickener to the liquid lubricant is between 1:0.5 and 1:

5.

7. The method for preparing a lubricating grease for the friction pair interface of engineering steel according to claim 6, characterized in that: The following steps are involved: First, at least one organic modifier is selected, and the thickener is modified by a solvent treatment method. The selected organic modifier is dissolved in anhydrous ethanol, and then the thickener is added for modification. If two or more organic modifiers are selected, they need to be stirred and mixed first, and then the thickener is modified by the above method, and the anhydrous ethanol is removed by heating at 40-60°C in an oven, and then the modified thickener is mixed into the liquid lubricant in a certain proportion, and then stirred and mixed to obtain a grease for the friction pair interface of engineering steel; When two or more organic modifiers or liquid lubricants are stirred, a magnetic stirrer is used at a rotation speed of 100-800 rpm; when the liquid lubricant and the thickener are mixed, a magnetic stirrer is also used at a rotation speed of 100-800 rpm.

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