SH/T 0716-2002 Determination of Fretting Wear Resistance of Lubricating Greases

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Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: SH/T 0716—2002
• Chinese name: Determination of Fretting Wear Resistance of Lubricating Greases
• English name: Test method for fretting wear protection by lubricating greases
• Replacement relationship: not provided in the available source (the foreword does not give a replaced standard number)
• Adoption relationship: equivalent adoption of ASTM D 4170-97 "Standard Test Method for Fretting Wear Resistance of Lubricating Greases"
• Main technical differences from ASTM D 4170-97 (foreword):
  1. This standard adds a frequency converter;
  2. This standard uses only n-heptane as solvent.
• Publication/implementation: published on 2002-05-31, implemented on 2002-07-01; issued by the State Bureau of Petroleum and Chemical Industry
• Responsible committee: Sinopec Research Institute of Petroleum Processing
• Drafting organization: Sinopec Chongqing Yiping Lubricant Branch
• Main drafters: Tian Zhongli, Chen Dapeng

2. Scope of application and non-applicability

• 1.1 This standard specifies a test method for determining the fretting wear resistance of lubricating greases.
• 1.2 Values expressed in international units are the standard values; other unit values are for reference only.
• 1.3 This standard involves certain hazardous materials, operations and equipment, but it is not intended to address all safety issues associated with them; users should establish appropriate safety and protective measures before using this standard, and determine an applicable management system.
• 5 This test method is used to evaluate the fretting wear resistance characteristics of lubricating greases when bearings oscillate; it is applicable to distinguishing low, medium and high fretting wear resistance of different lubricating greases under specified occasions and test conditions; it has been applied to predict the fretting wear resistance of automotive wheel bearing greases during long-distance transport.
• 5 The results of this test are not necessarily correlated with other types of wear phenomena; the user is responsible for determining the correlation between the results of this test and other types of wear phenomena.
• Non-applicable scope: not explicitly listed in the available source.

3. Method principle

• 4 Method summary: two sets of thrust ball bearings filled with test grease perform oscillating motion at an arc of 0.21 (12°), an oscillation frequency of 30.0 Hz (1800 cpm), a load of 2450 N (550 lbf), and room temperature, with a test duration of 22 h. The average of the sum of the mass losses of the two sets of bearing races (in mg) is used as the evaluation of the fretting wear resistance of the test grease.
• Note (4): The arc, frequency and load are operating conditions specified by the manufacturer and should not be changed. The constant of the loading spring may change after a certain period of time, so the spring should be calibrated periodically. If necessary, the spring length can be adjusted by adding a suitable shim to obtain the required load (±3%).
• 3 Definition: fretting wear fretting wear—— a form of wear produced by fine particles worn off friction surfaces undergoing vibration or oscillating motion at a specific amplitude. (The note also discusses fretting corrosion, friction oxidation, false Brinelling and the wear mechanism process, which are explanatory content.)

4. Reagents and materials (purity / preparation)

• 7 Reagent: n-heptane: analytical grade or meeting the requirements of GB/T 11117.2. Warning: flammable, harmful to the body.
• 8.3 For cleaning: distilled water (pour 30 mm~40 mm deep into the ultrasonic cleaner tank); n-heptane about 125 mL/ times (250 mL beaker).
• 9.2 If the set screw loosens during the test, a low-concentration anaerobic sealant (grade H in MIL-S22473D or an equivalent product) may be applied to the threads.
• 9.2.12 Note: Any grease with low fretting wear may be used (applied to the surface of the fixture in contact with the cavity).
• 9.2.14 Note: Add one drop of lubricating oil to the bearings at both ends of the connecting rod; lubricate frequently (automatic transmission fluid is suitable).
• Preparation of other reagents: not provided in the available source.

5. Apparatus and equipment

• 6.1 Favner friction oxidation test machine: model 11636 (or Falex (Falex) fretting wear test machine, model F-1581), structure shown in Figure 1 and Figure 2.
• 6.2 Spring guide cylinder: dimensions shown in Figure 3.
• 6.3 Thrust ball test bearing: inner diameter 16.00 mm±0.025 mm, outer diameter 35.69 mm±0.025 mm, assembled height 15.75 mm±0.25 mm, cage equipped with 9 steel balls of diameter 7.142 mm, all surfaces other than the cage are ground. Ground bearing races meeting the requirements of clause 6.3 should be used; if the races are not well ground, they may also be used after regrinding. Inspect the bearing races with a magnifier to determine whether they have been ground; bearing races with a part number have been ground. For a complete and detailed drawing of the test bearing with dimensions and specifications, see ASTM RR: D 02-1159.
• 6.4 Test machine frame.
• 6.5 Clock.
• 6.6 Analytical balance: range 100 g, sensitivity 0.1 mg.
• 6.7 Ultrasonic cleaner.
• 6.8 Frequency converter: range 0 Hz~100 Hz.
• Figure 3 Spring guide cylinder design dimensions: A=31.75 mm±0.25 mm; B=23.02 mm±0.05 mm; C=13.614 mm±0.013 mm (the dimension label and tolerance sign are unclear in the source transcription; verify the displayed dimension and tolerance against the original).
• Other tools (non-numbered equipment): scraper, lint-free cloth, tweezers or forceps or medical gloves, small-handle hex wrench, wooden mallet of about 0.5 kg, bench vise, engraving machine, V type block/surface grinder (mentioned in the note).

6. Recommended operating conditions

• Oscillation arc: 0.21 (12°)
• Oscillation frequency: 30.0 Hz (1800 cpm)
• Load: 2450 N (550 lbf)
• Temperature: room temperature
• Test duration: 22 h±0.1 h (9.4)
• Note (4): The arc, frequency and load are manufacturer-specified operating conditions and should not be changed; spring calibration should be performed periodically; a suitable shim may be used to adjust the spring length to obtain the required load (±3%).
• Frequency converter range: 0 Hz~100 Hz (6.8).

7. Sampling and specimen preparation

• Sampling: not provided in the available source.
• Specimen (test grease) filling and preparation see 9.1:
  • 9.1 In a clean environment, fill the test lubricating grease into two sets of unused, cleaned and weighed bearings.
  • 9.1.1 Fill the test lubricating grease into the steel ball raceway of the bearing race, and use a suitable scraper to spread the grease level with the bearing shoulder; the back of the bearing and the bearing seat must be ensured free of grease and particulate impurities, and may be gently wiped clean with a lint-free cloth moistened with n-heptane.
  • 9.1.2 Carefully fill all gaps around the steel balls on both sides of the cage with the test lubricating grease, and scrape off excess grease from the cage holes and edges, but excess grease is allowed to remain on the concave side; the grease amount for each bearing is required to be controlled within the range of 1.0 g±0.05 g.
• Bearing cleaning and drying (8.3~8.5):
  • 8.3 Pour distilled water 30 mm–40 mm deep into the ultrasonic cleaner tank; place two sets of bearings into a 250 mL beaker containing about 125 mL n-heptane, cover the beaker and place it in the ultrasonic bath, after cleaning for 10 min–15 min, place the bearing parts into a second beaker containing 125 mL n-heptane, after cleaning for 8 min–10 min, repeat the operation twice more, each rinse for 4 min–5 min; use fresh n-heptane and rinse beakers each time.
  • 8.4 Place the bearing parts on a clean glass dish or aluminum dish to dry naturally; the bearings should be placed against the edge of the dish to allow air circulation; when cleaning the bearings, do not rotate the bearings or blow with air; do not place the bearings on unclean glass or metal surfaces; do not touch the bearings with bare hands, use tweezers or forceps, or wear medical gloves.
  • 8.5 After the bearings are dry, place the dish containing the bearings into a desiccator to dry, and leave for at least 30 min.
  • 8.6 Weigh the mass of the upper and lower sets of bearing races separately, to the nearest 0.1 mg (each set of bearings contains two races, top and bottom).

8. Analytical procedure

• 8.1 Grind a flat surface suitable for the set screw on the outer cylindrical surface of each bearing race, with dimensions of about 8 mm×4 mm×0.5 mm; the flat surface must be rectangular to prevent the race from tilting when tightening the set screw. Note: A V type block may be used for embedding and then grinding with a surface grinder.
• 8.2 Use an engraving machine to engrave suitable marks on the outer platform surface of the bearing races to distinguish the upper and lower bearing races; the marks should not be engraved on the back or outer cylindrical surface of the races.
• 8.3~8.5 Bearing cleaning and drying (see Section 7).
• 8.6 Weigh the mass of the upper and lower sets of bearing races separately, to the nearest 0.1 mg.
• 9.1 Grease filling (see Section 7).
• 9.2 Fixture assembly (see Figure 4), assemble in the order specified in Figure 4; use only minimal force when tightening the set screws; the ground flat surface of the bearing race should face the set screw; a small-handle hex wrench is preferred; if the set screw loosens, a low-concentration anaerobic sealant (grade H in MIL-S22473D or an equivalent product) may be applied to the threads, do not tighten with excessive force; the bearing race must be installed in the bearing base, which can be checked visually and by touch.
  • 9.2.1 Install the upper bearing top race into the fixture head, and tighten the set screw with minimal force.
  • 9.2.2 Turn the fixture head upside down and place it in a bench vise to clamp.
  • 9.2.3 Place the upper bearing cage onto the top race of the fixture head, with the concave side facing up during assembly (facing down during operation).
  • 9.2.4 Install the upper bearing base ring into the oscillating bearing housing, and tighten the fixing screws with minimal force (all bearing fixing screws should be in the same direction; make a permanent mark on the lower side of the rocker arm of the oscillating bearing housing; when assembling in the same direction, the lower bearing seat ring should always be installed in the same base).
  • 9.2.5 Install the lower bearing top seat ring into the oscillating bearing housing, and tighten the fixing screws with minimal force.
  • 9.2.6 Install the oscillating bearing housing on the shaft so that the upper bearing is assembled correctly.
  • 9.2.7 Place the lower bearing cage onto the seat ring in the oscillating bearing housing, with the concave side facing up.
  • 9.2.8 Install the lower bearing base ring into the fixture base, and tighten the fixing screws with minimal force.
  • 9.2.9 Install the fixture base onto the fixture shaft.
  • 9.2.10 Install the spring guide cylinder, spring, spring washer (if needed), spacer, washer, and locknut in order on the shaft, hold the fixture base and oscillating bearing housing by hand to prevent rotation, and tighten the locknut until the bottom of the spacer rests against the shaft shoulder. Note: Spring calibration may affect the degree of wear; a reference mark can be made on the spring, and during installation always align the mark with the fixing screw in the fixture base.
  • 9.2.11 Remove the assembled fixture, loosen the fixing screws of all bearing seat rings; hold the fixture base with one hand, and with the other hand use approximately 0.5 kg wooden mallet to strike the top of the shaft to seat the bearings; finally, gently tighten all fixing screws.
  • 9.2.12 Apply a thin layer of grease to the fixture surfaces that contact the cavity.
  • 9.2.13 Install the fixture steadily into the cavity, and tighten the fixing screws on the side of the cavity. Note: Some fixture bases do not have a flat surface for the fixing screws, and a rectangular flat surface of approximately 9.5 mm×9.5 mm×0.5 mm that matches the cavity fixing screws must be pre-ground.
  • 9.2.14 Connect the connecting rod to the rocker arm of the oscillating bearing housing, add a drop of lubricating oil to the bearings at both ends of the connecting rod, and then install the protective device. Note: Before each test, check whether the bearings at the end of the connecting rod are worn; when the first sign of looseness appears, replace the bearings with new ones; frequent lubrication (automatic transmission fluid is suitable) can extend bearing life; check whether the O ring at the top of the fixture is swollen or otherwise damaged, and replace if necessary.
• 9.3 Place the testing machine on an anti-vibration frame. Note: It can be placed on a whole anti-vibration pad (or equivalent); placing appropriately sized pads (approximately 75 mm×75 mm) under each support foot of the testing machine can more effectively prevent vibration; staggered pad grain can improve vibration control.
• 9.4 Turn on the power, start the frequency converter and motor, start timing with a clock, and the test running time is 22 h±0.1 h.
• 9.5 After the test is finished, shut down the frequency converter and motor, disassemble the testing machine, and remove all bearing components from the fixture.
• 9.6 First wipe off most of the grease from the bearings with a clean soft cloth, then clean and dry the bearings according to 8.3~8.5.
• 9.7 According to 8.6, separately weigh the mass of the upper and lower bearing seat rings, to the nearest 0.1 mg.

9. Qualitative and Quantitative and Calculation Formulas

• 10.1 Separately calculate the mass loss of the upper and lower bearing seat rings, excluding the mass loss of the steel balls and cages; then calculate the average mass loss of the upper and lower bearing seat rings.
• 10.2 Report the average mass loss of the upper and lower bearing seat rings, in units of mg, to the nearest 0.1 mg, as the test result.
• 10.3 Calculate the mass loss ratio, i.e., the ratio of the mass loss of the upper bearing seat ring to the mass loss of the lower bearing seat ring.
• Precision calculation formulas (11.1.1, 11.1.2):
  • Repeatability = 1.4√X (the original text source-text extraction is "1.4/X", requires confirmation against the source standard (source-text extraction))
  • Reproducibility = 3.0√X (the original text source-text extraction is "3.0/ yuan", requires confirmation against the source standard (source-text extraction))
  • Where: X— the average mass loss of two tests, mg (in the reproducibility formula, X is the average mass loss of two separate tests, mg)
• Other calculation formulas: not provided in the available source.

10. Precision

• 11.1 Precision: Judge the reliability of test results according to the following provisions (95% confidence level).
• 11.1.1 Repeatability: The difference between two test results obtained by the same operator using the same equipment under the same operating conditions on the same test material, correctly operated according to the test method, shall not exceed the specified value (see Table 1). Repeatability = 1.4√X (source-text extraction doubtful point, requires confirmation against the source standard).
• 11.1.2 Reproducibility: The difference between two separate test results obtained by different operators in different laboratories on the same test material, correctly operated according to the test method, shall not exceed the specified value (see Table 1). Reproducibility = 3.0√X (source-text extraction doubtful point, requires confirmation against the source standard).
• Table 1 Repeatability and Reproducibility:

• 11.1.3 The mass loss ratio does not require precision analysis, but the mass loss ratio was determined in interlaboratory tests, and the resulting mass loss ratios were in the following ranges:

• 11.2 Bias: There is no bias when operating according to this test method, because the fretting wear value is determined solely based on the test method conditions.

11. Report

• 10.2 Report the average mass loss of the upper and lower bearing seat rings, in units of mg, to the nearest 0.1 mg, as the test result.
• 10.3 Calculate the mass loss ratio (ratio of the mass loss of the upper bearing seat ring to the mass loss of the lower bearing seat ring).
• Report format/template: not provided in the available source.

12. Reference Documents

• GB/T 11117.2 Knock test reference fuels - reference fuel n-heptane
• ASTM D 4170-97 "Standard Test Method for Fretting Wear Resistance of Lubricating Greases" (equivalent adoption object, see foreword)
• MIL-S22473D Medium H grade or equivalent product (mentioned in 9.2, not listed in the reference standards section)
• ASTM RR: D 02-1159 (6.3 mentions test bearing diagram, not listed in the reference standards section)

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Q&A Reference