Plain bearings - Testing of bearing materials - Resistance to corrosion by lubricants under static conditions
1 Scope
This document establishes a test of the corrosion-resistance of bearing materials to lubricants. It also specifies the most important general principles for carrying out such corrosion testing.
This document is applicable to the performance test of resistance to corrosion by lubricants and the selection of bearing materials.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
3.1
corrosion
reaction of a bearing material to its environment, causing a measurable change in the material and which can result in corrosion damage
Note: In most cases, this reaction is of a chemical nature. It can, however, also involve chemical or mechanical processes. Material changes solely caused by or found only in combination with mechanical influences are not dealt with in this document. For a detailed explanation of the various causes of damage to plain bearings, see ISO 7146-1.
4 Health and safety
Resources, test pieces, test materials, test equipment and test procedures shall comply with the current health and safety regulations/laws. Where equipment, materials and/or reagents that may be hazardous to health are specified, appropriate precautions in conformity with local regulations/laws shall be taken.
5 General principles
5.1 Corrosion tests are carried out as comparison tests, i.e. several materials and lubricants are compared with one another. However, it is also possible to include already known behaviour in the test reference materials or reference lubricants.
5.2 The duration of the test shall be chosen, and, if necessary, extended, so that at the end of the test, definite information on the corrosion behaviour of the material tested and, possibly, of the reference material can be obtained under the specified test conditions.
5.3 A value for a single material test is less informative, owing to a greater dispersion of the results, which often occurs when determining an increase or decrease in mass. Therefore, each result shall be given as a mean value from at least three tests.
6 Lubricants
The quantity of lubricant used shall be at least 10 mL/cm2 of bearing material surface.
Specifications indicating the type and performance level of the oils are used to characterize the lubricants used for the tests.
In order to be able to draw conclusions concerning, for example, the additives used and their effect, the chemical and physical data should be given, as follows:
- density at 15℃, in grams per millilitre (g/mL, i.e. g/cm3);
- flash point, in degree Celsius;
- neutralization value;
- saponification value;
- base number;
- kinematic viscosity at 40℃, in square millimetres per second;
- kinematic viscosity at 100℃, in square millimetres per second;
- sulfate ash yield, as a percentage by mass;
- zinc content, as a percentage by mass;
- phosphorus content, as a percentage by mass;
- barium content, as a percentage by mass;
- calcium content, as a percentage by mass;
- content of sulfur in corrosive forms, as a percentage by mass.
7 Apparatus
7.1 Beaker(s), of sufficient capacity to allow each test sample to be fully immersed.
7.2 Heating bath, preferably an oil bath, capable of maintaining the required temperature to within ±2℃. The heating bath shall be large enough to allow the beaker to be immersed up to three quarters of its height to prevent overspill of heating bath fluid into the test beaker.
8 Preparation of test samples
8.1 The preferred test sample shall be a complete bearing. Where this is not possible, a test sample of bearing material shall be cut out from parts sufficiently large that any influences of strong mechanical cold-working and of high temperature rise at the edges of the cut are eliminated. Burrs shall be removed.
8.2 The surface of the bearing material shall not be less than 25 cm² in order to eliminate as far as possible the influence of irregularities. If one bearing surface area is less than 25 cm², consider using more than one in the test vessel and combine the result.
8.3 The surface condition of test samples during the tests shall agree as far as possible with the surface condition of the bearing material in practice. The test sample shall be thoroughly cleaned and degreased. Suitable organic solvents (e.g. white spirit or methanol) should be used.
8.4 Test samples shall be clearly marked. Marking methods which harm the mechanical strength of the bearing (e.g. electromechanical methods) shall be avoided.
9 Test procedure
Perform the following test procedure before testing.
a) Record the mass, dimensions and roughness of the test samples.
b) Place the bearing material test samples in the beakers (7.1) in such a way that they are completely covered by the lubricant in order to avoid the influence at the phase limit air/lubricant. Protect the beakers against dirt by means of a cover.
c) In principle, test only samples of the same bearing material in one beaker in order to avoid any interaction. The atmosphere shall be free from any substance which could interfere with the test.
d) During the test, maintain the beakers at the specified test temperature to within ±2 ℃. Recommended test temperatures are 80℃, 100℃, 120℃, 150℃ and 180℃.
The duration of the test shall be 20 days at least; it may be extended if necessary (see 5.2). Intermediate assessments shall be made after one week and after two weeks. Test temperatures and test times should be chosen to reflect operating conditions in the intended bearing application.
e) For the purpose of the intermediate and final assessments, clean the test samples by spraying using an appropriate solvent or by other means. Dry them in a hot-air cabinet until a constant mass is attained. Record the mass and dimensions.
Standard
GB/T 42613-2023 Plain bearings—Testing of bearing materials—Resistance to corrosion by lubricants under static conditions (English Version)
Standard No.
GB/T 42613-2023
Status
valid
Language
English
File Format
PDF
Word Count
5500 words
Price(USD)
165.0
Implemented on
2023-12-1
Delivery
via email in 1~3 business day
Detail of GB/T 42613-2023
Standard No.
GB/T 42613-2023
English Name
Plain bearings—Testing of bearing materials—Resistance to corrosion by lubricants under static conditions
Plain bearings - Testing of bearing materials - Resistance to corrosion by lubricants under static conditions
1 Scope
This document establishes a test of the corrosion-resistance of bearing materials to lubricants. It also specifies the most important general principles for carrying out such corrosion testing.
This document is applicable to the performance test of resistance to corrosion by lubricants and the selection of bearing materials.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
3.1
corrosion
reaction of a bearing material to its environment, causing a measurable change in the material and which can result in corrosion damage
Note: In most cases, this reaction is of a chemical nature. It can, however, also involve chemical or mechanical processes. Material changes solely caused by or found only in combination with mechanical influences are not dealt with in this document. For a detailed explanation of the various causes of damage to plain bearings, see ISO 7146-1.
4 Health and safety
Resources, test pieces, test materials, test equipment and test procedures shall comply with the current health and safety regulations/laws. Where equipment, materials and/or reagents that may be hazardous to health are specified, appropriate precautions in conformity with local regulations/laws shall be taken.
5 General principles
5.1 Corrosion tests are carried out as comparison tests, i.e. several materials and lubricants are compared with one another. However, it is also possible to include already known behaviour in the test reference materials or reference lubricants.
5.2 The duration of the test shall be chosen, and, if necessary, extended, so that at the end of the test, definite information on the corrosion behaviour of the material tested and, possibly, of the reference material can be obtained under the specified test conditions.
5.3 A value for a single material test is less informative, owing to a greater dispersion of the results, which often occurs when determining an increase or decrease in mass. Therefore, each result shall be given as a mean value from at least three tests.
6 Lubricants
The quantity of lubricant used shall be at least 10 mL/cm2 of bearing material surface.
Specifications indicating the type and performance level of the oils are used to characterize the lubricants used for the tests.
In order to be able to draw conclusions concerning, for example, the additives used and their effect, the chemical and physical data should be given, as follows:
- density at 15℃, in grams per millilitre (g/mL, i.e. g/cm3);
- flash point, in degree Celsius;
- neutralization value;
- saponification value;
- base number;
- kinematic viscosity at 40℃, in square millimetres per second;
- kinematic viscosity at 100℃, in square millimetres per second;
- sulfate ash yield, as a percentage by mass;
- zinc content, as a percentage by mass;
- phosphorus content, as a percentage by mass;
- barium content, as a percentage by mass;
- calcium content, as a percentage by mass;
- content of sulfur in corrosive forms, as a percentage by mass.
7 Apparatus
7.1 Beaker(s), of sufficient capacity to allow each test sample to be fully immersed.
7.2 Heating bath, preferably an oil bath, capable of maintaining the required temperature to within ±2℃. The heating bath shall be large enough to allow the beaker to be immersed up to three quarters of its height to prevent overspill of heating bath fluid into the test beaker.
8 Preparation of test samples
8.1 The preferred test sample shall be a complete bearing. Where this is not possible, a test sample of bearing material shall be cut out from parts sufficiently large that any influences of strong mechanical cold-working and of high temperature rise at the edges of the cut are eliminated. Burrs shall be removed.
8.2 The surface of the bearing material shall not be less than 25 cm² in order to eliminate as far as possible the influence of irregularities. If one bearing surface area is less than 25 cm², consider using more than one in the test vessel and combine the result.
8.3 The surface condition of test samples during the tests shall agree as far as possible with the surface condition of the bearing material in practice. The test sample shall be thoroughly cleaned and degreased. Suitable organic solvents (e.g. white spirit or methanol) should be used.
8.4 Test samples shall be clearly marked. Marking methods which harm the mechanical strength of the bearing (e.g. electromechanical methods) shall be avoided.
9 Test procedure
Perform the following test procedure before testing.
a) Record the mass, dimensions and roughness of the test samples.
b) Place the bearing material test samples in the beakers (7.1) in such a way that they are completely covered by the lubricant in order to avoid the influence at the phase limit air/lubricant. Protect the beakers against dirt by means of a cover.
c) In principle, test only samples of the same bearing material in one beaker in order to avoid any interaction. The atmosphere shall be free from any substance which could interfere with the test.
d) During the test, maintain the beakers at the specified test temperature to within ±2 ℃. Recommended test temperatures are 80℃, 100℃, 120℃, 150℃ and 180℃.
The duration of the test shall be 20 days at least; it may be extended if necessary (see 5.2). Intermediate assessments shall be made after one week and after two weeks. Test temperatures and test times should be chosen to reflect operating conditions in the intended bearing application.
e) For the purpose of the intermediate and final assessments, clean the test samples by spraying using an appropriate solvent or by other means. Dry them in a hot-air cabinet until a constant mass is attained. Record the mass and dimensions.
