GB/T 3142-1982 Determination of load-carrying capacity of lubricants (four-ball method)
Some standard content:
National Standard of the People's Republic of China
Lubricants-determination of load-carryingcapaclty (four balls method) UDC678.048.4
GB3142—82
This method is applicable to the evaluation of the load-carrying capacity of lubricants on a four-ball extreme pressure testing machine, including the maximum no-seizure load P, the burnout load Pp, and the comprehensive wear value ZMZ. In practical applications, different evaluation criteria can be selected according to the various uses of lubricants. Note: ① The maximum no-seizure load is commonly known as the P point (representing the oil film strength). ② The comprehensive wear value ZMZ is also known as the comprehensive wear index, the average Hertz load, and the load-wear index. 1 Method
In the four-ball machine, four steel balls are arranged in an equilateral tetrahedron. The upper ball rotates at 1400-1500 rpm. The three balls below are fixed together by an oil box, and the load is applied to the steel balls from bottom to top through a lever or hydraulic system. During the test, the contact points of the four steel balls are immersed in the lubricant. Each test lasts for 10 seconds. After the test, the wear scar diameter of any steel ball in the oil pan is measured. The test is repeated according to the prescribed procedure until the evaluation index representing the bearing capacity of the lubricant is obtained. 2.1 Hertz diameter and Hertz line: The diameter of the concave surface (D., mm) formed by the elastic deformation of the steel ball under a certain static load (P) is called the Hertz diameter under the pressure.
Dt=8.73× 10-t(Po)
Where: P is a static load (actual load), kg. In the load-wear diameter double logarithmic coordinate diagram, the relationship between D, and P is a straight line, called the Hertz line. （)
2.2 Compensation line and compensation diameter. In the presence of lubricant and without seizure, bright circular spot-shaped wear cancer is produced on the three balls below: A straight line drawn in the double logarithmic coordinate diagram from the average wear scar diameter of the lower ball to the applied load is called the compensation line. The wear scar diameter corresponding to a certain load on the compensation line is called the compensation diameter under the load. The compensation lines of different lubricants are close and can be represented by a compensation line representing a uniform slope, as shown in Figure 1. 2,3 Wear-load curve: On the double logarithmic coordinate, a curve drawn from the average wear scar diameter of the balls under different loads (see curve ABCD in Figure 2). The meaning of each part of the wear-load curve is marked in Figure 2. 2.4 Maximum non-seizure load P. (kg): The highest load (kg) under the test conditions without seizure. It represents the oil film strength. The wear scar diameter measured under this load shall not be greater than 5% of the value on the corresponding compensation line. 2.6 Sintering load P. (kg): The minimum load (kg) that causes the steel ball to sinter under the test conditions: It represents the ultimate working capacity of the lubricant.
2.6 Correction load Pcorrection (kg): It is the correction of the expected actual load P, PwP-D./D..
Wherein, D——Hertz diameter, mm:
D——Actual wear scar diameter, mm.
2.7 The total wear value ZMZ is an index of the extreme pressure resistance of the lubricant. It is equal to the mathematical average of several correction loads: ZMZ=4+B/2=A++A++B./2.
Published by the Inspection Bureau of Standards on July 20, 1982
Implemented on March 1, 1983
Or for general grease, 2MZ4i+A&+B/2
GB 3142—82
Wu Zhong, A when P is higher than 400 kg, A is the sum of 8 correction loads of 315 kg and less than 315 kg, when P is less than or equal to 400 kg, A is the sum of 10 correction loads; when P is higher than 400 kg, 8 is the arithmetic mean of the correction loads from 400 kg to before sintering, when B-
P, is less than or equal to 400 kg, B is zero: A,-P point before, that is, the sum of the correction loads on the compensation line, from Table 3: A,-P point after, the sum of the correction loads before 315 kg, 0.6
3 Only goods and materials
: 3.1 Four-ball extreme pressure testing machine
678910
202530
Negative, kg
Compensation line of four-ball machine
40 ± 50 60 70 80 90100
156 200 250
One burning point
Negative load
50 t00
Negative section, kg
5001000
Figure 2 Loss-load curve
The core part of the four-ball extreme pressure testing machine is shown in Figure 3. The structure and installation requirements of the four-ball extreme pressure testing machine are as follows; GB 3142—82
The ball on the steel plate can rotate at 1400~1500 rpm.
Load force
Figure 3 Schematic diagram of four-ball extreme pressure test machine
The main shaft speed of the four-ball machine is 1460±50 rpm, and the load range is 6~800 kg. The four-ball machine should have a rigid film-resistant structure. The radial runout of the friction part (upper steel ball) of the four-ball machine shall not exceed 0.02 mm when measured at 3.5 mm from the lowest point of the steel ball.
It is best not to do both extreme pressure test and wear test on the same four-ball machine to avoid affecting the sensitivity of the wear test. 3.2 Microscope: equipped with a micrometer, the reading value is 0.01 mm 3.3 Stopwatch, the division is 0.1 second,
3.4 Steel ball: grade bearing steel ball that meets the requirements of GB308 "Steel Ball", with a diameter of 12.7 mm and a material of GCr15. Note: Steel balls that meet the above requirements can be purchased from Shanghai Steel Ball Factory. 4 Reagents
4.1 Direct flame gasoline or solvent gasoline.
4,2 Petroleum ether: 60 ~90 ℃.
5 Preparation
5.1 Start the motor and run it idle for 29 minutes.
5.2 Use solvent gasoline to clean the steel ball, oil box, fixture and other parts that come into contact with the sample during the test, then use petroleum ether to wash twice, and then blow dry. The cleaned steel ball should be smooth and free of rust (after each sample test, repeat the above steps to prepare for the next test).
6 Test steps
6.1 Fix the steel ball in the upper ball seat and oil box of the four-ball machine respectively. Pour the sample into the oil box so that the sample covers the steel ball and reaches the joint between the pressure ring and the nut. If the test is latent grease, first put a sufficient amount of grease in the oil box, embed the ball in the grease, put the pressure ring, tighten the frequency to tighten the oil box, smooth the grease on the surface and adjust it to the joint between the pressure ring and the nut. There should be no holes in the sample. 6.2·Place the oil box with the sample and the ball in the middle under the upper ball seat, put the disc rack between the oil cup and the guide column, release the loading lever and add the specified load to the ball. Avoid impact during loading. The four-ball machine with oil pressure loading can be loaded according to the requirements of the instruction manual.
6.3 After loading, start the motor and press the stopwatch at the same time. The test time from start to shut down is 10 seconds. 6.4 After each test, measure the wear diameter of any steel ball in the oil basin in both the vertical and horizontal directions. GB3142-82
6.5 Regarding the maximum no-seizure load P, when measuring P, it is required that the wear scar diameter under the maximum no-seizure load P, shall not be greater than 5% of the wear scar diameter on the corresponding compensation line (i.e. compensation diameter). If the measured wear scar diameter under a certain load is 5% greater than the wear scar diameter on the corresponding compensation line, the next test shall be carried out under a lower load, and this operation shall be continued until the maximum no-seizure load is determined. In order to simplify the test procedure, this method provides a table of P~D (1+5%) for judging the P point (Table 1). In Table 1, D represents the compensation diameter corresponding to the load P. For example, the wear scar diameter of a certain oil under a load of 80 kg is 0.47 mm. According to Table 1, D compensation (1+5%) is 0.44 mm under a load of 80 kg. It can be concluded that the P point of the oil is less than 80 kg. The requirements for the determination of the H point are as follows: P is below 40 kg, and the accuracy is 2 kg; P is between 41 and 80 kg, and the accuracy is 3 kg; P is between 81 and 120 kg, and the accuracy is 5 kg; P is between 121 and 160 kg, and the accuracy is 7 kg; P is above 160 kg, and the accuracy is 10 kg.
6.6 About the sintering load P.The test is generally started from 80 kg load, and the test is carried out according to the load level indicated in Table 2 until sintering occurs. It is required to repeat once. If sintering occurs twice, the load used in the side test is used as the sintering load. If sintering does not occur in the repeated test, a new test and repeated test with a larger load are required. When sintering occurs, the motor should be turned off in time, otherwise it will cause serious wear and tear, and the steel ball and the chuck will even burn together with the upper cone seat. The following phenomena can help determine whether sintering has occurred: a. The friction recording pen tip has a violent lateral movement: b. The motor noise level increases,
c. The oil box smokes:
d. The loading lever arm is suddenly lowered.
Some lubricants with strong extreme pressure performance have not yet reached the real sintering, and the diameter of the steel ball wear scar has reached the limit value. The load that produces the maximum wear scar diameter of 4 mm is taken as the sintering point. Some lubricants do not sinter under extremely high loads, and the limit load of the machine is 800 kg.
Note that according to test experience, it is appropriate to tighten the oil box to a torque of 8.5 kg when measuring the sintering load. The lower ball does not roll during the test, and the reproducibility of point P can be improved.
6.7 Determination of the comprehensive wear value ZMZ: First determine which level the P= point of the sample belongs to in wave 2, and then start from a load one level higher than point P., and gradually increase the load until sintering. Check the total load correction table on the compensation line (Table 3), and calculate the comprehensive wear value according to formula (3).
Fill in and report
7.1 Maximum no-seizure load P: Report the maximum no-seizure load Pa in kilograms. 7.2 Sintering load Pn: Report the number of sintering load P,. 7. Comprehensive wear value ZMZ: Calculate and report the comprehensive wear value according to formula (3). B Precision
Use the following values to judge the reliability of the results (95% confidence rate), 8.1 Repeatability
8.1.1 When measuring P,, the difference between the two results of repeated measurements by one operator on one machine shall not exceed 15% of the average value. 8.1,2 When measuring P,, the difference between the two results of repeated measurements by the same operator on the same machine shall not exceed one load level. 8.1.3 When measuring ZMZ, the difference between the two results of repeated measurements by the same operator on the same machine shall not exceed 10% of the average value.
8.2 Reproducibility
8.,2.1 When measuring P,, the difference between the measurements of the same sample by two laboratories shall not exceed 30% of the average value. 8.2.2 When determining P, the difference between the results of the same sample measured by two laboratories should not be greater than one load level. 8.2.3 When determining ZMZ, the difference between the results of the same sample measured by two laboratories should not be greater than 26% of the average value. GB3142-82
B.3 Report: The arithmetic mean of the two repeated measurements is used as the measurement result. Note. The precision of grease and lubricants that do not obey the average compensation line (the entire wear-load curve is above the average compensation line) has not been determined. Table 1 of P~D material (1+5%) used to determine P point
P, kg
D (1+6%)
P, kg
D# pipe (1+5%)
P, kg
D# brand (1+5%)
P, kg
D# (1+5%)
0.67 1 0.58
0.24 0.25
0.600,61
Note, if the load is between two grids, take the value of the latter grid. For example, P=120 kg, then take D# general (1+5%)=0.50 whole meter. Table 2 Four-ball machine test record
Test number:
Specimen name
Specimen formula:
Load P
Machine model:
Speed:
Steel ball:
Room temperature,
ground
Entrusting unit:
Operator:
Proofreader,
Test date,
Calibration load
Pfloor, kg
Test results
Maximum no-stuck
bite load P.
GB 3142--82
Table 3 Total table of correction load on compensation line
380,5380,5
174.9 211.2
·45,5
GB3142-82
Inspection of accuracy
(Supplement)
The accuracy of the four-ball machine shall be inspected at least once a year. The method is as follows: Use a standard force ring to inspect the load accuracy of the four-ball machine. The maximum non-seizure load Pg, sintering load P, and comprehensive wear value ZMZ of four reference greases were determined. The data of the reference greases are listed in Table A1l.
Table A1 Reference samples of four-ball machine
Sample number
Sample name
No. 8 aviation lubricating oil, produced by Lanzhou Refinery No. 20 aviation lubricating oil plus 3% olefin sulfide
No. 18 hyperbolic gear oil, produced by Fushun Petroleum Plant No. 1 grease, developed by Petrochemical Research Institute
Maximum non-seizure load
P kg
Sintering load Pp
Comprehensive wear value
$B 314282
Carving B
Runqing Jing Embedding Capacity Test Method (Jiang Ball Method) Examples (Sen Test Part)
B, 1 Make the compensation line, P-D (1 + 5%) table and the correction negative sum table on the compensation line for the domestic Jishan four-ball machine. Note: The compensation lines of various types of four-ball machines are very similar. Other types of four-ball machines can directly refer to the compensation line and P-D (main + 5%) table (Table 1 of this method) and the correction negative sum table on the compensation line (Table 3 of this method) provided by this standard, without having to make another table. B.1.1 Select 8 representative samples with different viscosities and different P points. Their properties are shown in Table B1 of this appendix. Table B1 Determine the compensation line? Types of oil samples www.bzxz.net
Pa, kg
B1.2 According to Table B2 of this Appendix, measure the wear scar diameter of various oil samples at various loads without seizure, and take the average value, and draw a compensation line representing the average slope on the double logarithmic coordinate graph (see this method 1, measure three balls in each test, the diameter of each ball parallel and perpendicular to the direction of the close scar, and take the average value of 8 values as the increased diameter). B.1.3 Extrapolate the compensation line to B~315 kg, find the compensation straight line under various loads, and calculate the correction load value (see Table B3 of this Appendix)
Table B2
Load P
Average value
GB. 3142-82
B,1.4 Calculate the corresponding P,,P for each group from the correction load value provided in Table B3. The sum of the correction negative loads on the compensation line, i.e. the value of Ai, is used to make a table of the sum of the correction loads on the compensation line (Table 3 of the wide version method) - for example, in Table 3, P = 50 kg, Ps 500 kg, the A1 value in the intersection grid is found in Table B3, and the correction negative value of Pa 50 kg is 45.48. For another example, if P = 6 kg, P-500 kg, the A value in the intersection grid is found in Table B3, and P = 50 kg, P = 63 kg. The sum of these two levels of correction loads is: 46.48 + 56.78 = 102.26. For another example, if Pa = 80 kg, P, 500 kg, the A value in the intersection grid is found in Table B3, and P = 50 kg, P = 83 kg, P = 80 kg, the sum of these three levels of correction load, 45.48 + 56.78 + 72.66 - 174.92, and so on, make the correction negative extraction total table on the entire compensation line,
Table B3
Load level
Negative intercept P, Public Hall
B, 2 Determine the P, P, and zMz values of double-tooth-i oil. The specific method is as follows:
PD coefficient
Compensation diameter D
.0 .194
Correction load
P teaching kg
.·11.72
B.2.1 Double gear one oil is a high extreme pressure gear oil, so it is not necessary to start from 80 kg, it can be started from 160 kg, the wear scar diameter D is measured to be 0.54 mm, according to Table 1 of this method, it does not exceed P point. The load is increased by one level, P200 kg, the wear scar diameter D is measured to be 1.19 mm, obviously it has exceeded P point, it can be seen that P point is between 1.60 and 200 kg, and then 165 kg is done, the wear scar diameter D is measured to be 0.62 mm, according to Table 1, it has exceeded Pa point, and the accurate P point is determined to be 160 kg. B,2,2 then do 250 kg, 315 kg, 400 kg, 600 kg, until 620 kg when sintering occurs, repeat once and sintering also occurs, then stop the test.
Look up the intersection of P=160 kg and P=820 kg in Table 3 of this method, and get A,=52B, and then according to the data in Table B4 of this Appendix, A±A,+A,=526+(85.88+86.48+95,48)=793.82, Note, when looking up Table 9, special attention should be paid to the level of Pg, for example, if P-165 kg, then P=160 kg should be used. If P,=158 kg, then P=126 kg should be used.
Test code:
Specimen name, double tooth-1
Sample formula:
GB 3142—$2
Model: Jishan
Speed: 1420rpm
Steel ball, Hubei ball
Room temperature: 20℃
Trace diameter, m
Entrusting unit
Operator:
Proofreader,
Test period, 1980.8.10
8/211.18+±150.2266:35
Correction negative
Pw kg
.95.46
115,18
zM z.m4+B/2_793.92±66.35 m86.0210
At - 526
A, =287.82
Total A-793.82
8/2×66.35
P:=180 kg
Pp=620 kg
ZMZ-86.02
If it is not required to determine the precise maximum non-seizure load Pz of double gear-1, but only to determine P, and ZMZ, P=165 kg is not necessary
In very rare cases, when the oil is set to P, there is an abnormal phenomenon between the two loads. This may be an error in the operation, but it may also be the inherent characteristics of the lubricant itself. In this case, it should be repeated at a higher load level to eliminate doubts. For example, when P is 160 kg, the oil film is broken, but when P=200 kg, the oil film is not broken. At this time, P=200 kg should be repeated. If it is broken, determine P. 160 kg, if it does not knock, it is definitely P, >200 kg, but it should be noted that the oil film breaking and not breaking repeatedly in a smaller load range is a normal phenomenon, and there is no need to repeat the test.
Additional Notes
GB 3142--82
This standard is proposed by the Ministry of Petroleum Industry of the People's Republic of China. It is under the jurisdiction of the Petrochemical Research Institute. This standard is drafted by the Petrochemical Research Institute, and the main drafter of this standard is Wei Danping.
From the date of implementation of this standard, the original Ministry of Petroleum Standard SY265-77 "Method for Determination of Lubricating Swimming Load Capacity (Four-Ball Method)" will be invalid
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