Method for testing water resistance of composite calcium sulfonate-based lubricating grease

Abstract

The invention discloses a method for testing the water resistance of composite calcium sulfonate-based lubricating grease, which specifically comprises the following steps: uniformly smearing the composite calcium sulfonate-based lubricating grease on the inner wall of a roller body, putting a roller, adding water, and tightening a sealing cover of the roller body; placing the cylinder body coated with the lubricating grease on a roller shearing instrument, clamping the cylinder body of the roller and a clamping groove position of the roller shearing instrument so that the cylinder body can only rotate and cannot shake left and right, carrying out a shearing test, cooling to room temperature after the shearing test is completed, pouring out water which is not absorbed in the roller, and weighing the mass of the water which is not absorbed; calculating the water absorption rate of the composite calcium sulfonate-based lubricating grease, wherein the water absorption rate is equal to the water absorption amount / the added water amount; the water absorption amount is equal to the sum of the added water amount and the mass of the unabsorbed water. According to the method, a roller acting mode is adopted, so that the composite calcium sulfonate soap core fully absorbs water, the water absorption performance of the composite calcium sulfonate-based lubricating grease is measured, and the water absorption performance of the lubricating grease is fully reflected. And the method has practical guiding significance on the type selection of the lubricating grease used in high-temperature and high-humidity environments.

Description

Technical Field

[0001] The invention belongs to the technical field of grease performance testing methods, and in particular relates to a method for testing the water resistance of a composite calcium sulfonate-based grease. Background Art

[0002] There are four main test methods for the water resistance of grease: (1) SH / T 0109 test method for the water resistance of grease, which mainly tests the amount of grease lost during the rotation of the bearing under water spray; (2) SH / T 0643 test method for the water spray resistance of grease, which mainly tests the adhesion of grease to metal under static conditions; (3) DIN 51807 test method for the behavior of grease in the presence of water, which tests the degree of deterioration of grease under water under static conditions; (4) NB / SH / T 0872-2013 test method for the shear stability of grease in the presence of water.

[0003] Composite calcium sulfonate-based grease has been recognized by the market for its excellent water resistance, high temperature resistance, corrosion resistance, high extreme pressure, wear resistance and good mechanical stability. It is used in a series of heavy-duty equipment with a large amount of water and complex water quality, such as the lubrication of bearings in the papermaking, cement, steel and other industries. Although composite calcium sulfonate-based grease has good water resistance, complex environments can still cause some composite calcium sulfonate-based greases with average water resistance to absorb water and deteriorate, resulting in lubrication failure and causing many problems for the normal operation of the equipment. Therefore, how to judge and evaluate the water resistance of composite calcium sulfonate-based grease is particularly important for enterprises to select greases and develop water-resistant greases in a targeted manner.

[0004] To test its water resistance, we must first select a highly simulated operating condition, and the test results must be distinguishable and quantifiable.

[0005] At present, these four methods for testing the water resistance of grease have different focuses. When used to test composite calcium sulfonate-based grease, which has excellent water resistance, they cannot show obvious differentiation. Method 1 is close to the actual operating conditions of composite calcium sulfonate-based grease, but the test data does not have great differentiation, and it is difficult to judge the water resistance of the product; Method 2 focuses on determining the adhesion of grease under static conditions, which can be quantified, and the test data has good differentiation, but it is not a rotating equipment; Method 3 is a visual inspection result under static conditions, the working conditions are not close and the test results cannot be observed by naked eye alone, and cannot be quantified; Method 4 focuses on testing the viscosity change after the grease is mixed with a small amount of water, and the working condition simulation is not strong. Summary of the invention

[0006] The purpose of the present invention is to provide a method for testing the water resistance of a composite calcium sulfonate-based grease, which can effectively test the water absorption rate of the composite calcium sulfonate-based grease and evaluate the water resistance of the product.

[0007] The technical solution adopted by the present invention is a method for testing the water resistance of composite calcium sulfonate-based grease, which is specifically implemented according to the following steps:

[0008] Step 1: Apply the composite calcium sulfonate-based grease evenly on the inner wall of the drum body, put the roller in, add water, and tighten the cover of the drum body to prevent the water and grease in the drum body from leaking;

[0009] Step 2: Place the cylinder coated with grease on the roller shear tester, lock the roller cylinder and the slot of the roller shear tester so that the cylinder can only rotate but not shake left and right, and perform the shear test. After the test is completed, cool it to room temperature, pour out the unabsorbed water in the roller, and weigh the mass of the unabsorbed water;

[0010] Step 3: Calculate the water absorption of the calcium sulfonate complex grease.

[0011] The present invention is also characterized in that:

[0012] In step 1, the mass ratio of water to composite calcium sulfonate-based grease is 2 to 10:1.

[0013] In step 2, when the shear test is performed, the temperature is 25°C to 100°C and the time is 2h to 100h.

[0014] In step 2, the rotation speed of the drum is 165 rpm.

[0015] In step 3, the calculation process of the water absorption rate of the composite calcium sulfonate-based grease is: water absorption rate = water absorption amount / added water amount; water absorption amount = added water amount - the mass of unabsorbed water.

[0016] The invention has the beneficial effects that the main soap part of the composite calcium sulfonate-based lubricating grease thickener is composed of calcium sulfonate-coated calcium carbonate, and the external hydrophobic long-chain sulfonic acid group and the internal water-absorbing calcium carbonate determine that the soap core of the composite calcium sulfonate-based lubricating grease has water absorption, and the soap core is more likely to absorb water when doing work. The invention adopts the roller working method to make the composite calcium sulfonate soap core fully absorb water, and the water absorption performance of the composite calcium sulfonate-based lubricating grease is measured, which fully reflects the water absorption performance of the lubricating grease. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with specific implementation modes.

[0018] Example 1

[0019] The water resistance test method of the composite calcium sulfonate-based grease of the present invention is specifically implemented according to the following steps:

[0020] Step 1: Apply the composite calcium sulfonate-based grease evenly on the inner wall of the drum body, put the roller in, add water, and tighten the cover of the drum body to prevent the water and grease in the drum body from leaking;

[0021] The mass ratio of water to composite calcium sulfonate-based grease is 2 to 10:1;

[0022] Step 2: Place the greased cylinder on the roller shear tester. According to the requirements of the roller shear test, lock the slots of the roller and the roller shear tester so that the cylinder can only rotate but not shake left and right. Cover the box and lock the buckle. Perform the shear test. After completion, cool to room temperature, pour out the unabsorbed water in the roller, and weigh the mass of the unabsorbed water.

[0023] When conducting the shear test, the temperature is 25°C to 100°C, the time is 2h to 100h, and the drum speed is 165 rpm.

[0024] A high-temperature roller shear instrument and high-humidity conditions were used to simulate the working conditions of the composite calcium sulfonate-based grease. The composite calcium sulfonate-based grease was operated under large amounts of water to examine its water absorption and evaluate the water resistance of the sample in the presence of large amounts of water.

[0025] The equipment and instruments used in the test of the present invention are conventional equipment and instruments for grease testing projects. The test method is closer to the actual use conditions of the composite calcium sulfonate-based grease. The test conditions are representative and can better reflect the water resistance of the grease during actual use.

[0026] Step 3: Calculate the water absorption of the calcium sulfonate complex grease;

[0027] Specifically: water absorption rate = water absorption / water added; water absorption = water added - the mass of unabsorbed water;

[0028] The water absorption should be controlled within a certain range. Water absorption is an inevitable characteristic of composite calcium sulfonate-based grease. Appropriate water absorption can keep the grease better and improve its metal protection performance. If the water absorption is too large, the grease is easy to emulsify and swell, making the lubrication ineffective. Therefore, the water absorption process of composite calcium sulfonate-based grease should not be too large.

[0029] Example 2

[0030] The water resistance test method of the composite calcium sulfonate-based grease of the present invention is specifically as follows:

[0031] Step 1: Weigh two 50g samples of the tested composite calcium sulfonate-based grease sample A, sample B, and sample C respectively, apply them evenly on the inner wall of the drum, put the roller in, add 100g of pure water respectively, and tighten the cover of the drum;

[0032] Step 2: Place the grease cylinder on the high-temperature roller shearing equipment. According to the roller shearing test requirements, lock the roller cylinder and the roller shearing instrument in place so that the cylinder can only rotate but not shake left and right. Cover the box, turn down the buckle, and plug in the power supply.

[0033] Step 3: Turn on the drum shearing machine and heat it to 80°C, set the operating time to 50 hours, turn on the drum shearing machine and turn the button to start shearing;

[0034] Step 4: After the drum shearing machine has been running for 50 hours, the instrument automatically stops. When the temperature drops to room temperature, open the box, take out the two drums, and open the drum covers;

[0035] Step 5: Pour out the water inside the cylinder separately and weigh the amount of water that has not been absorbed;

[0036] Step 6: Calculate the water absorption of the composite calcium sulfonate-based grease;

[0037] Step 7: Calculate the water absorption of the calcium sulfonate complex grease and take the average value of the two samples.

[0038] Table 1 Water absorption test results of composite calcium sulfonate grease

[0039]

[0040] It can be seen from the test data in Table 1 that the water absorption rates of the three composite calcium sulfonate-based grease samples after roller shearing are different. The water absorption rate of grease A is 0.48, the water absorption rate of grease B is 0.96, and the water absorption rate of grease C is 1. This shows that the 100 grams of water added to grease C is completely absorbed, causing the grease to emulsify and expand in volume, and it cannot effectively lubricate the grease friction parts. Grease C has poor water resistance.

[0041] Example 3

[0042] The water resistance test method of the composite calcium sulfonate-based grease of the present invention is specifically as follows:

[0043] Step 1: Weigh two 50g samples of the tested composite calcium sulfonate-based grease samples A, B and C respectively, apply them evenly on the inner walls of two drums, put the rollers in, add 100g of pure water respectively, and tighten the cover of the drum;

[0044] Step 2: Place two grease cylinders on the high-temperature roller shearing equipment. According to the roller shearing test requirements, lock the roller cylinder and the roller shearing instrument in place so that the cylinder can only rotate but not shake left and right. Cover the box, turn down the buckle, and plug in the power supply.

[0045] Step 3: Turn on the drum shearing machine and heat it to 80°C, set the operating time to 100h, turn on the drum shearing machine and turn the button to start shearing;

[0046] Step 4: After the drum shearing machine has been running for 100 hours, the instrument automatically stops. When the temperature drops to room temperature, open the box, take out the two drums, and open the drum covers;

[0047] Step 5: Pour out the water inside the cylinder separately and weigh the amount of water that has not been absorbed;

[0048] Step 6: Calculate the water absorption of the composite calcium sulfonate-based grease;

[0049] Step 7: Calculate the water absorption of the calcium sulfonate complex grease and take the average value of the two samples.

[0050] Table 2 Test data of composite calcium sulfonate grease

[0051]

[0052]

[0053] It can be seen from the test data in Table 2 that after 100 hours of roller shearing, the water absorption rate of grease A, grease B and grease C is 0.48, 0.98 and 1 respectively for the three composite calcium sulfonate-based grease samples. The water absorption rate of grease A is still the smallest, indicating that the water absorption rate of composite calcium sulfonate-based grease is related to the composition structure of the grease.

[0054] The method of the present invention can effectively test the water absorption rate of composite calcium sulfonate-based grease and evaluate the water resistance of the product. It can be used to develop highly water-resistant grease and to substantially evaluate the water resistance of composite calcium sulfonate-based grease, and has practical guiding significance for the selection of grease for use in high temperature and high humidity environments.

Claims

1. A method for testing the water resistance of composite calcium sulfonate-based grease, characterized in that: Follow the steps below to implement it: Step 1: Apply the composite calcium sulfonate-based grease evenly on the inner wall of the drum body, put the roller in, add water, and tighten the cover of the drum body to prevent the water and grease in the drum body from leaking; Step 2: Place the cylinder coated with grease on the roller shear tester, lock the roller cylinder and the slot of the roller shear tester so that the cylinder can only rotate but not shake left and right, and perform the shear test. After the test is completed, cool it to room temperature, pour out the unabsorbed water in the roller, and weigh the mass of the unabsorbed water; Step 3: Calculate the water absorption of the calcium sulfonate complex grease.

2. The method for testing the water resistance of composite calcium sulfonate-based grease according to claim 1, characterized in that: In the step 1, the mass ratio of water to the composite calcium sulfonate-based grease is 2 to 10:

1.

3. The method for testing water resistance of composite calcium sulfonate-based grease according to claim 1, characterized in that: In step 2, when the shear test is performed, the temperature is 25° C. to 100° C. and the time is 2 h to 100 h.

4. The method for testing water resistance of composite calcium sulfonate-based grease according to claim 1, characterized in that: In step 2, the rotation speed of the drum is 165 rpm.

5. The method for testing water resistance of composite calcium sulfonate-based grease according to claim 1, characterized in that: In step 3, the calculation process of the water absorption rate of the composite calcium sulfonate-based grease is: water absorption rate = water absorption amount / added water amount; water absorption amount = added water amount-the mass of unabsorbed water.

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