Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 3142-1982 Lubricants - Determination of load-carrying capacity (four balls method).
In addition to a number of editorial changes, the following main technical changes have been made with respect to GB/T 3142-1982:
——SI units are adopted as the measurement units.
——Clause 2 "Normative references" is added;
——The compensation line of four-ball machine in Figure 1 of GB/T 3142-1982 is moved to Annex B.
——The wrong expression in GB/T 3142-1982 is corrected; “5%” in 3.4 and 8.9 is changed to “(1+5%)”.
——The expression for P in equations is added in 3.6 and explanation is made for lever-type four-ball machine.
——The detailed description on reagents is added in 5.1.
——The requirements for the material and hardness of test steel ball are added in 5.2.
——The detailed description on instrument is added in Clause 6.
——The load range of four-ball machine is enlarged to “59N~9810N”. Corresponding modifications are made in 6.1; Class 23 load is added in Table 1 and corresponding sum of corrected load is added in Table 4.
——The relevant contents of periodic calibration on four-ball machine are added. The description on calibration of four-ball machine is added in the note in 6.1; corresponding modification is made to the reference oil or grease for four-ball machine and a note is added in Table A.1 of Annex A.
——The preparations for rotating speed and test environment temperature of four-ball machine are added in 7.1 “preparation”.
——The detailed test steps and precautions are added in Clause 8, and detailed requirements for reading of wear spot diameter are specified.
——For ease of use, Table 3 is added in 8.9, which is established based on the measuring accuracy levels of PB, and the operator can directly perform test according to the levels specified in this table. The determination method of PB for new lubricants, especially unconventional lubricants, is added in this note.
——The explanation of PB accuracy level is added for looking up Table 4 in 8.11.
This standard was proposed by National Technical Committee on Petroleum Products and Lubricants of Standardization Administration of China (SAC/TC 280).
The previous edition of this standard is as follows:
——GB/T 3142-1982.
Standard test method for determination of load-carrying capacity of lubricants - Four-ball method
Caution——the application of this standard may involve certain hazardous materials, operations and equipment. However, recommendations are not proposed for all safety issues related to the above. It is the responsibility of the users of this standard to prepare corresponding safety and protection measures and to determine the applicability of regulatory limitations prior to use.
1 Scope
This standard specifies the method for determination of load-carrying capacity of lubricants with four-ball extreme pressure tester, including the determination of last nonseizure load (PB), weld point (PD) and combined wear number (ZMZ).
This standard is applicable to lubricants. In practical applications, different evaluation indicators may be selected according to the different purposes of lubricants.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 308.1-2013 Rolling bearings - Balls - Part 1: Steel balls
GB 1922-2006 Petroleum solvents for paints and cleaning
GB/T 15894-2008 Chemical reagent - Petroleum ether
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
Hertz scar diameter
Dh
scar diameter caused by the elastic deformation of steel ball under certain static load, which may be calculated using Equation (1):
Dh=4.08×10-2Pstatic1/3 (1)
Where,
Dh——the Hertz scar diameter, mm;
Pstatic——the static load, N.
3.2
Hertz line
one straight line representing the relationship between Hertz scar diameter and static load in a load-wear spot diameter log-log graph
3.3
compensation line
one straight line representing the relationship between the average wear spot diameter and the applied load in a log-log graph in the presence of lubricant but without seizure, wherein, the average wear spot diameter is the average of bright round spotted wear spots produced on the lower three balls; the compensation lines for different lubricants are approximate and may be represented by a compensation line representing the average slope, as shown in Figure 1
3.4
compensation scar diameter
Dcompensation
wear spot diameter corresponding to certain load on compensation line
3.5
load-wear line
one line made by the average wear spot diameter of a steel ball under different loads on log-log graph (see line ABCD in Figure 1); the meaning of different parts of load-wear line is indicated in Figure 1
3.6
last nonseizure load
PB
maximum load without seizure under test conditions, which represents oil film strength; the wear spot diameter measured under such load shall not be greater than (1+5%) the value (Dcompensation) on corresponding compensation line
Note: seizure refers to the damage of oil film of lubricant, which may be seen by the increase in wear spot diameter and the instantaneous increase in measured friction.
3.7
weld point
PD
minimum load causing weld on steel ball under test conditions, which represents the ultimate working capacity of lubricants
3.8
corrected load
Pcorrected
correction to the applied actual load P, which may be calculated using Equation (2):
Pcorrected=P·Dh/D (2)
Where,
P——the actual load. If a lever-type four-ball machine is adopted, P is the total weight (weights plus weight disks) multiplied by the lever arm ratio, in N;
Dh——the Hertz scar diameter, mm;
D——the wear spot diameter measured, mm.
3.9
combined wear number
ZMZ
index of lubricant resistance to extreme pressure, which is equal to the arithmetic average of several corrected loads and may be calculated using Equation (3):
(3)
Where,
A——the sum of 9 classes of corrected loads not greater than 3090N where PD is greater than 3924N; or the sum of 10 classes of corrected loads where PD is less than or equal to 3924N;
B——the arithmetic average of different classes of corrected loads from 3924N to weld where PD is greater than 3924N; or 0 where PD is less than or equal to 3924N;
A1——the sum of corrected loads in front of PB point on compensation line;
A2——the sum of corrected loads less than 3090N behind PB point.
Keys:
ABE——compensation line;
AB——area without seizure;
B——last nonseizure load point;
BC——area with delayed seizure;
CD——area close to seizure;
D——weld point.
Figure 1 Load-wear line
4 Method summary
Arrange the four steel balls in a regular tetrahedron, the upper ball rotates at a rotating speed of 1450r/min±50r/min, and the lower three balls are fixed together by an oil box, and apply load to the steel balls by lever or hydraulic system from bottom to top. The contact points of the four steel balls are immersed in the lubricant during the test. The test period is 10s, and measure the wear spot diameter of any of the steel balls in the oil box after test. Repeat the test according to the specified procedures until an evaluation indicator representing the load-carrying capacity of lubricant is obtained.
5 Reagents and materials
5.1 Reagents
5.1.1 Detergent: 1# solvent oil complying with GB 1922-2006.
Caution——it is flammable and harmful to health.
5.1.2 Petroleum ether: petroleum ether complying with GB/T 15894-2008, with boiling range of 60℃~90℃.
Caution——it is flammable and harmful to health.
5.2 Materials
5.2.1 Steel ball: special test steel ball for four-ball machine. The material complies with the requirements for E-52100 chrome alloy steel ball in American ANSI standard or the high-carbon chromium bearing steel ball in GB/T 308.1-2013, with diameter of 12.7mm and hardness of HRC 61~66.
5.2.2 Reference oil or grease: see Table A.1 in Annex A for the specification requirements.
6 Instruments
6.1 Four-ball extreme pressure tester: the structure and technical parameters are as follows:
a) the core part of four-ball extreme pressure tester is shown in Figure 2;
b) the rotating speed of mainshaft of four-ball machine is 0r/min~3000r/min and the load range is 59N~9810N;
c) the four-ball machine shall have a rigid vibration-resistant structure. The radial run-out tolerance of the friction components (upper steel ball) of four-ball machine shall not exceed 0.02mm measured at 3.5mm from the lowest point of steel ball. Every year, the four-ball extreme pressure tester shall be calibrated with reference oil or grease (see Annex A) and the reliability of its compensation line shall be inspected (see Annex B).
Note: extreme pressure test and wear test shall not be conducted on the same four-ball machine so as to avoid affecting the sensitivity of wear test.
6.2 Microscope: direct-reading microscope with micrometer or automatic precision measuring instrument. The reading shall be accurate to 0.01mm.
6.3 Timer: accurate to 0.1s.
6.4 Friction recorder: an instrument directly recording the changes in friction.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Method summary
5 Reagents and materials
6 Instruments
7 Preparation
8 Test steps
9 Result report
10 Precision and deviation
Annex A (Normative) Inspection for accuracy of four-ball machine
Annex B (Informative) Example for determination method (four-ball method) of load-carrying capacity of lubricant
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 3142-1982 Lubricants - Determination of load-carrying capacity (four balls method).
In addition to a number of editorial changes, the following main technical changes have been made with respect to GB/T 3142-1982:
——SI units are adopted as the measurement units.
——Clause 2 "Normative references" is added;
——The compensation line of four-ball machine in Figure 1 of GB/T 3142-1982 is moved to Annex B.
——The wrong expression in GB/T 3142-1982 is corrected; “5%” in 3.4 and 8.9 is changed to “(1+5%)”.
——The expression for P in equations is added in 3.6 and explanation is made for lever-type four-ball machine.
——The detailed description on reagents is added in 5.1.
——The requirements for the material and hardness of test steel ball are added in 5.2.
——The detailed description on instrument is added in Clause 6.
——The load range of four-ball machine is enlarged to “59N~9810N”. Corresponding modifications are made in 6.1; Class 23 load is added in Table 1 and corresponding sum of corrected load is added in Table 4.
——The relevant contents of periodic calibration on four-ball machine are added. The description on calibration of four-ball machine is added in the note in 6.1; corresponding modification is made to the reference oil or grease for four-ball machine and a note is added in Table A.1 of Annex A.
——The preparations for rotating speed and test environment temperature of four-ball machine are added in 7.1 “preparation”.
——The detailed test steps and precautions are added in Clause 8, and detailed requirements for reading of wear spot diameter are specified.
——For ease of use, Table 3 is added in 8.9, which is established based on the measuring accuracy levels of PB, and the operator can directly perform test according to the levels specified in this table. The determination method of PB for new lubricants, especially unconventional lubricants, is added in this note.
——The explanation of PB accuracy level is added for looking up Table 4 in 8.11.
This standard was proposed by National Technical Committee on Petroleum Products and Lubricants of Standardization Administration of China (SAC/TC 280).
The previous edition of this standard is as follows:
——GB/T 3142-1982.
Standard test method for determination of load-carrying capacity of lubricants - Four-ball method
Caution——the application of this standard may involve certain hazardous materials, operations and equipment. However, recommendations are not proposed for all safety issues related to the above. It is the responsibility of the users of this standard to prepare corresponding safety and protection measures and to determine the applicability of regulatory limitations prior to use.
1 Scope
This standard specifies the method for determination of load-carrying capacity of lubricants with four-ball extreme pressure tester, including the determination of last nonseizure load (PB), weld point (PD) and combined wear number (ZMZ).
This standard is applicable to lubricants. In practical applications, different evaluation indicators may be selected according to the different purposes of lubricants.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 308.1-2013 Rolling bearings - Balls - Part 1: Steel balls
GB 1922-2006 Petroleum solvents for paints and cleaning
GB/T 15894-2008 Chemical reagent - Petroleum ether
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
Hertz scar diameter
Dh
scar diameter caused by the elastic deformation of steel ball under certain static load, which may be calculated using Equation (1):
Dh=4.08×10-2Pstatic1/3 (1)
Where,
Dh——the Hertz scar diameter, mm;
Pstatic——the static load, N.
3.2
Hertz line
one straight line representing the relationship between Hertz scar diameter and static load in a load-wear spot diameter log-log graph
3.3
compensation line
one straight line representing the relationship between the average wear spot diameter and the applied load in a log-log graph in the presence of lubricant but without seizure, wherein, the average wear spot diameter is the average of bright round spotted wear spots produced on the lower three balls; the compensation lines for different lubricants are approximate and may be represented by a compensation line representing the average slope, as shown in Figure 1
3.4
compensation scar diameter
Dcompensation
wear spot diameter corresponding to certain load on compensation line
3.5
load-wear line
one line made by the average wear spot diameter of a steel ball under different loads on log-log graph (see line ABCD in Figure 1); the meaning of different parts of load-wear line is indicated in Figure 1
3.6
last nonseizure load
PB
maximum load without seizure under test conditions, which represents oil film strength; the wear spot diameter measured under such load shall not be greater than (1+5%) the value (Dcompensation) on corresponding compensation line
Note: seizure refers to the damage of oil film of lubricant, which may be seen by the increase in wear spot diameter and the instantaneous increase in measured friction.
3.7
weld point
PD
minimum load causing weld on steel ball under test conditions, which represents the ultimate working capacity of lubricants
3.8
corrected load
Pcorrected
correction to the applied actual load P, which may be calculated using Equation (2):
Pcorrected=P·Dh/D (2)
Where,
P——the actual load. If a lever-type four-ball machine is adopted, P is the total weight (weights plus weight disks) multiplied by the lever arm ratio, in N;
Dh——the Hertz scar diameter, mm;
D——the wear spot diameter measured, mm.
3.9
combined wear number
ZMZ
index of lubricant resistance to extreme pressure, which is equal to the arithmetic average of several corrected loads and may be calculated using Equation (3):
(3)
Where,
A——the sum of 9 classes of corrected loads not greater than 3090N where PD is greater than 3924N; or the sum of 10 classes of corrected loads where PD is less than or equal to 3924N;
B——the arithmetic average of different classes of corrected loads from 3924N to weld where PD is greater than 3924N; or 0 where PD is less than or equal to 3924N;
A1——the sum of corrected loads in front of PB point on compensation line;
A2——the sum of corrected loads less than 3090N behind PB point.
Keys:
ABE——compensation line;
AB——area without seizure;
B——last nonseizure load point;
BC——area with delayed seizure;
CD——area close to seizure;
D——weld point.
Figure 1 Load-wear line
4 Method summary
Arrange the four steel balls in a regular tetrahedron, the upper ball rotates at a rotating speed of 1450r/min±50r/min, and the lower three balls are fixed together by an oil box, and apply load to the steel balls by lever or hydraulic system from bottom to top. The contact points of the four steel balls are immersed in the lubricant during the test. The test period is 10s, and measure the wear spot diameter of any of the steel balls in the oil box after test. Repeat the test according to the specified procedures until an evaluation indicator representing the load-carrying capacity of lubricant is obtained.
5 Reagents and materials
5.1 Reagents
5.1.1 Detergent: 1# solvent oil complying with GB 1922-2006.
Caution——it is flammable and harmful to health.
5.1.2 Petroleum ether: petroleum ether complying with GB/T 15894-2008, with boiling range of 60℃~90℃.
Caution——it is flammable and harmful to health.
5.2 Materials
5.2.1 Steel ball: special test steel ball for four-ball machine. The material complies with the requirements for E-52100 chrome alloy steel ball in American ANSI standard or the high-carbon chromium bearing steel ball in GB/T 308.1-2013, with diameter of 12.7mm and hardness of HRC 61~66.
5.2.2 Reference oil or grease: see Table A.1 in Annex A for the specification requirements.
6 Instruments
6.1 Four-ball extreme pressure tester: the structure and technical parameters are as follows:
a) the core part of four-ball extreme pressure tester is shown in Figure 2;
b) the rotating speed of mainshaft of four-ball machine is 0r/min~3000r/min and the load range is 59N~9810N;
c) the four-ball machine shall have a rigid vibration-resistant structure. The radial run-out tolerance of the friction components (upper steel ball) of four-ball machine shall not exceed 0.02mm measured at 3.5mm from the lowest point of steel ball. Every year, the four-ball extreme pressure tester shall be calibrated with reference oil or grease (see Annex A) and the reliability of its compensation line shall be inspected (see Annex B).
Note: extreme pressure test and wear test shall not be conducted on the same four-ball machine so as to avoid affecting the sensitivity of wear test.
6.2 Microscope: direct-reading microscope with micrometer or automatic precision measuring instrument. The reading shall be accurate to 0.01mm.
6.3 Timer: accurate to 0.1s.
6.4 Friction recorder: an instrument directly recording the changes in friction.
Contents of GB/T 3142-2019
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Method summary
5 Reagents and materials
6 Instruments
7 Preparation
8 Test steps
9 Result report
10 Precision and deviation
Annex A (Normative) Inspection for accuracy of four-ball machine
Annex B (Informative) Example for determination method (four-ball method) of load-carrying capacity of lubricant
