SH/T 0784-2006 Standard test method for extreme pressure properties of lubricating greases (high-frequency linear vibration test machine method)

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Card type: Test method

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

• Standard number: SH/T 0784—2006
• Chinese full title: Standard test method for extreme pressure properties of lubricating greases (high-frequency linear vibration test machine method)
• English name: Standard test method for determining extreme pressure properties of lubricating grease using a high-frequency, linear-oscillation (SRV) test machine
• Replacement relationship: not provided in the available source (no mention of replacing any old standard)
• Adoption relationship: modified adoption of ASTM D5706-97 (2002) "Standard test method for extreme pressure properties of lubricating greases (high-frequency linear vibration test machine (SRV) method)"
• Main differences from ASTM D5706-97 (2002): the keywords clause is deleted; the wording of repeatability and reproducibility is modified according to Chinese practice
• Publication/implementation: published on 2006-05-12, implemented on 2006-11-01
• Issuing body: National Development and Reform Commission of the People's Republic of China
• Custodian: Sinopec Research Institute of Petroleum Processing
• Drafting organization: Lubricant Yiping Branch of Sinopec Corp.
• Main drafters: Tian Zhongli, Yan Zili

2. Scope of application and non-applicability

• 1.1 specifies a method for determining the extreme pressure properties of lubricating greases under high-frequency linear vibration using a high-frequency linear vibration test machine (SRV).
• 1.2 may also be applicable to evaluating the extreme pressure characteristics of liquid lubricants.
• 1.3 uses International System of Units [SI] units.
• 1.4 involves certain hazardous materials, operations and equipment, but does not purport to address all safety problems associated with them; users should establish appropriate safety protective measures before use and determine the scope of applicability of the measures.
• Non-applicable scope: not provided in the available source.

3. Method principle

• 4 Method summary: on a SRV test machine, one test steel ball is used to perform a reciprocating vibration test under lubrication conditions at a fixed frequency. Test load is continuously applied in increments of 100N until seizure occurs. The test load corresponding to just before seizure occurs is reported.
• Note: the test frequency, amplitude, test temperature, test ball and test disk materials, etc. may all vary according to changes in simulated field conditions. The test ball produces a point contact pattern. To obtain line or area contact, specimens of different shapes may be used to replace the test ball.
• 5 Significance and use: it can rapidly determine the extreme pressure properties of lubricating greases under selected temperature conditions, and is suitable for determining the extreme pressure properties of lubricating greases under high Hertzian point contact conditions, high-speed vibration or oscillating motion. It is widely applicable to quality inspection of lubricating greases in constant velocity ball joints of front-wheel drive automobiles. Users should determine the correlation between test results and service performance or other applications.

4. Reagents and materials (purity / preparation)

• 7.3 n-Heptane: analytical reagent. Note: flammable, harmful to the body.
• 7.4 Isopropanol: analytical reagent. Note: flammable, harmful to the body.
• 7.5 Toluene: analytical reagent. Note: flammable, harmful to the body.
• 7.6 Cleaning solvent: an equal-volume mixture of n-heptane, isopropanol and toluene. Note: flammable, harmful to the body.
• 7.1 Test ball: 100 steel, hardness Rc is 60±2, surface roughness (Ra) is 0.030 (unit requires confirmation against the source standard (source-text extraction)); the source text also has the wording "R.0.65", suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction).
• 7.2 Test disk: 100 steel, hardness Rc is 60±2, ground surface roughness is 20.4 (unit requires confirmation against the source standard (source-text extraction)), diameter 7.85mm.
• Note: it is permissible to use steel manufactured with ... grade Cb (DIN 17230) (there is missing text here in the source text, requires confirmation against the source standard (source-text extraction)).

5. Apparatus and equipment

• 6.1 High-frequency linear vibration test machine (SRV), whose structure and principle are shown in Figure 1 and Figure 2.
• Figure 1 SRV Appearance and structure diagram of the test machine
• Figure 2 Test principle
• Other equipment: ultrasonic apparatus (used in 9.1 for vibration cleaning of specimens); heating controller (9.6); recorder (8.1, 8.6); digital timer (9.10); load amplifier (9.7, 9.8).
• Specific models/specifications: not provided in the available source (except that 8.2 mentions electronic card N291.35.20E and the sliding switch on the back plate of the control unit).

6. Recommended operating conditions

• 8.1 Turn on the test machine and recorder, and preheat the machine for 15min before testing.
• 8.2 Select the friction data corresponding to the position appearing at the maximum peak value according to the manufacturer's instructions. Note: in most cases, this can be done by locking the sliding switch on electronic card N291.35.20E (front side of the circuit board behind the panel) and the sliding switch located on the back plate of the control unit.
• 8.3 Turn the amplitude knob to "zero".
• 8.4 Set the stroke switch to the automatic position.
• 8.5 Set the frequency to 50Hz.
• 8.6 Set the required range and calibrate the recorder according to the manufacturer's instructions, then select the paper feed speed of the recording paper.
• 9.6 Turn on the heating controller and set the required test temperature.
• 9.7 Set the value of the load amplifier corresponding to the load of 400N.
• 9.9 After the temperature has stabilized, turn on the recording paper feed switch, lower the recording pen, press down the toggle-type start switch until the timer starts counting, then adjust the stroke amplitude knob to 1.00mm.
• 9.10 When the digital timer reaches 30s, use the slow speed position to apply the load to 100N, and keep this load running continuously for 2min (including the loading process). Using the slow speed position, increase the load by 100N every 2min until reaching the load of 1200N, or reaching the load limit of the test instrument, or failure occurring.
• Note: because running-in under 50N uses up 30s, load application should begin at the even minute 30 second mark, such as 4min30s, 6min30s.
• Note: SRV test machines produced after the year 1992 can reach a maximum load of 1400N.

7. Sampling and specimen preparation

• 9.2 Place a small amount (about 0.1g~0.2g) of lubricating grease sample on the cleaned test disk, avoiding overlap with previously produced wear scars.
• 9.3 Install the cleaned test ball on top and place it in the middle of the lubricating grease sample, so that the lubricating grease forms a circularly symmetric uniform thin layer between the test ball and the test disk.
• Other sampling requirements: not provided in the available source.

8. Analysis procedure

• 9.1 Clean and wipe the surfaces of the test ball and test disk with silk cloth carrying cleaning solvent, repeatedly wiping until there is no black residue on the silk cloth. Immerse the test ball and test disk in a beaker containing cleaning solvent, vibrate with an ultrasonic apparatus for 10min, then wipe the test ball and test disk clean with clean silk cloth to ensure that no streaks appear on the specimen surfaces.
• 9.2 Place a small amount (about 0.1g~0.2g) of lubricating grease sample on the cleaned test disk, avoiding overlap with previously produced wear scars.
• 9.3 Install the cleaned test ball on top and place it in the middle of the lubricating grease sample, so that the lubricating grease forms a circularly symmetric uniform thin layer between the test ball and the test disk.
• 9.4 After confirming that the test machine has no load (the load meter reading indicates -13N or -14N), carefully place the test disk containing the lubricating grease sample and the test ball onto the test platform area.
• 9.5 Tighten the fixtures of the test ball and test disk until just tight. Then, after loading to 100N, tighten the fixtures of the test ball and test disk so that the torque reaches 2.5N·m, then reduce the load to 50N.
• 9.6 Turn on the heating controller and set the required test temperature.
• 9.7 Set the value of the load amplifier corresponding to the load of 400N.
• 9.8 When examining the friction coefficient under each test load, the value of the load amplifier corresponding to each load should be changed according to the manufacturer's instructions.
• 9.9 After the temperature has stabilized, turn on the recording paper feed switch, lower the recording pen, then press down the toggle-type start switch until the timer starts counting, then adjust the stroke amplitude knob to 1.00mm.
• 9.10 When the digital timer reaches 30s, use the slow speed position to apply the load to 100N, and keep this load running continuously for 2min; this 2min includes the loading process. Using the slow speed position, increase the load by 100N every 2min until reaching the load of 1200N, or reaching the load limit of the test instrument, or failure occurring. Failure means that during vibration of the test machine the friction coefficient rises and the increase over the steady state is greater than 0.2, or shutdown occurs.
• 9.11 When the run at the load of 1200N ends or the maximum load of the test instrument is reached or failure occurs, the heating controller should be turned off, the load reduced to the minimum value (generally -13N or -14N), then the test ball and test disk disassembled, and the lubricating grease sample removed.

9. Qualitative and quantitative criteria and calculation formulas

• Qualitative criterion (seizure/failure): during vibration of the test machine the friction coefficient rises and the increase over the steady state is greater than 0.2, or shutdown occurs (9.10).
• 3.12 Seizure seizure: local melting of metal between the friction surfaces of the specimens. Note: in the test method, if the friction coefficient rises above the steady state by an increase of 0.2, it indicates that seizure has occurred. In severe cases ... operation (the source text is incomplete here, requires confirmation against the source standard (source-text extraction)).
• Quantitative result: report the maximum test load at which seizure did not occur (10.2).
• Calculation formula: not provided in the available source.

10. Precision

• 11.1 Eighteen operators tested eight lubricating greases with average load-carrying capacity on a SRV test machine, with load ranging from about 200N to about 700N.
• 11.2 Precision: judge the reliability of test results according to the following provisions (95% confidence level).
• 11.2.1 Repeatability: for repeated determinations of the same sample by the same operator using the same instrument under the same operating conditions, the difference between the two results obtained shall not exceed the following values:
  • Test run under 50℃: 0.7X
  • Test run under 80℃: 0.6 (X+122)
  • Where: X is the average of the two determination results, N.
• 11.2.2 Reproducibility: for determinations of the same sample by different operators in different laboratories, the difference between the two independent results obtained shall not exceed the following values:
  • Test run under 50℃: 1.3X
  • Test run under 80℃: 1.2 (X+122)
  • Where: X is the average of two determination results, N.
• 11.3 Bias: There is no bias in evaluating the load-carrying capacity of grease using this test method, because load-carrying capacity can only be defined according to this test method.

11. Report

• 10.1 Report the following test parameters:
  • 10.1.1 Temperature, ℃
  • 10.1.2 Stroke, mm
  • 10.1.3 Frequency, Hz
  • 10.1.4 Test ball
  • 10.1.5 Test disk
  • 10.1.6 Grease sample name
• 10.2 Report the maximum test load at which no seizure occurred.

12. Normative References

• DIN 17230 Rolling bearing steel (normative reference, dated/undated status not provided in the available source)
• ASTM D5706-97 (2002) (modified adoption of the original standard, see foreword)

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