NB/SH/T 0823-2010 Test method for corrosion preventive properties of lubricating greases in diluted synthetic seawater

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Card type: Test method

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

• Standard number: NB/SH/T 0823-2010
• Chinese title: Test method for corrosion preventive properties of lubricating greases in diluted synthetic seawater
• English title: Standard test method for corrosion-preventive properties of lubricating greases in presence of dilute synthetic sea water environments
• Replacement relationship: not provided in the available source (the foreword does not list the old standard number replaced)
• Adoption relationship: modified adoption of ASTM D5969-05 (the source writes "ASTM D5969 -05?", the year suffix is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)). This standard was redrafted according to ASTM D5969-05.
• Main differences from ASTM D5969-05: the referenced standards adopt the current national standards of our country; the imperial units involved in the figures are converted to International System of Units units; this standard adds Appendix A "Preparation of synthetic seawater".
• Publication/implementation: published on 2010-05-01, implemented on 2010-10-01; issuing authority: National Energy Administration.
• Custodianship: Sinopec Research Institute of Petroleum Processing; proposed by: China Petrochemical Corporation; drafting organization: Sinopec Research Institute of Petroleum Processing; main drafter: Yang Lingsha.

2. Scope of application and non-applicability

• 1.1 applies to determining the corrosion preventive performance of lubricating greases by storing tapered roller bearings coated with lubricating grease under humid conditions in diluted synthetic seawater environments of various concentrations.
• Based on the GB/T 5018 method, GB/T 5018 has test steps similar to this method and uses distilled water as the test medium.
• This method uses pass or fail as the evaluation result, and reports the result that is consistent for at least two of the three bearings.
• 1.2 This standard does not address all safety issues related to its use. Users should establish corresponding safety and protective measures before use and determine an applicable management system.
• Non-applicable scope: not provided in the available source.

3. Method principle

• 4 Method summary: a new, cleaned bearing filled with the lubricating grease sample is run under a light thrust load for 60s±3s, so that the lubricating grease is distributed on the bearing in the state it would be in actual application. The bearing is exposed to a synthetic seawater solution diluted with distilled water, stored for 24h±0.5h under conditions of 52℃±1℃ and 100% relative humidity, then cleaned and inspected for corrosion marks on the bearing outer ring.
• 5 Significance and use: this test method can be used to distinguish the relative corrosion preventive performance of different lubricating greases under the test conditions.
• 3.1 Definition of corrosion: a chemical or electrochemical reaction between a material (usually metal) and its environment, which can cause deterioration of the material and its properties. Note: In this standard, red rust or black spots on the raceway of the bearing outer ring are defined as corrosion. If the metal surface is still visible under a stain, the stain is not considered corrosion in this standard and should be ignored.

4. Reagents and materials (purity / preparation)

• 7.1 Distilled water: meets the requirements for grade three water in GB/T 6682.
• 7.2 Isopropanol: chemically pure. Caution: flammable.
• 7.3 Ammonium hydroxide: chemically pure. Caution: toxic, flammable, vapor is extremely irritating. If swallowed it can be fatal, and inhalation can cause injury.
• 7.4 Solvent cleaning liquid, composition as follows:
  • 7.4.1 Isopropanol: 90% (volume fraction).
  • 7.4.2 Distilled water: 9% (volume fraction).
  • 7.4.3 Ammonium hydroxide: 1% (volume fraction).
• 7.5 Solvent naphtha: solvent naphtha meeting the requirements for No. 3 in GB 1922 (Caution: flammable, vapor is toxic).
• 7.6 Synthetic seawater: prepared according to the method described in Appendix A (Caution: toxic, ingestion may be fatal).
• Appendix A Preparation of synthetic seawater (normative appendix):
  • A.1 Composition of synthetic seawater (mass volume concentration g/L): sodium chloride (NaCl) 24.54; magnesium chloride (MgCl₂·6H₂O) 11.10; sodium sulfate (Na₂SO₄) 4.09; calcium chloride (CaCl₂) 1.16; potassium chloride (KCl) 0.69; sodium bicarbonate (NaHCO₃) 0.20; potassium bromide (KBr) 0.10; boric acid (H₃BO₃) 0.03; strontium chloride (SrCl₂·6H₂O) 0.04; sodium fluoride (NaF) 0.003.
  • A.2.1 Prepare the following stock solutions using chemically pure reagents and distilled water:
    • 1 No. base solution: magnesium chloride (MgCl₂·6H₂O) 3885 g; calcium chloride (CaCl₂) anhydrous 406 g; strontium chloride (SrCl₂·6H₂O) 14 g; dissolve and dilute to 7 L.
    • 2 No. base solution: potassium chloride (KCl) 483 g; sodium bicarbonate (NaHCO₃) 140 g; potassium bromide (KBr) 21 g; boric acid (H₃BO₃) 2.1 g; sodium fluoride (NaF) requires confirmation against the source standard (source-text extraction, the source value is missing/unclear); dissolve and dilute to 7 L.
  • A.2.2 Dissolve 245.4 g sodium chloride (NaCl) and 40.94 g sodium sulfate (Na₂SO₄) in several liters of distilled water, add 200 mL 1 No. base solution and 100 mL 2 No. base solution, and dilute to 10 L, stir, then add 0.05 mol/L sodium carbonate solution (Na₂CO₃) until the pH value is 7.8–8.2 (about 1 mL–2 mL of sodium carbonate solution is required).

5. Apparatus and equipment

• 6.1 Bearing: composed of a LM11949 bearing cone and a LM11910 bearing outer ring.
• 6.2 Motor: speed is 1750 r/min±50 r/min, 0.05 W (minimum).
• 6.3 Bearing support (see Figure 1): includes a weight with a mass of 1 kg±0.01 kg, plastic flanges at the upper and lower ends of the bearing cone, a metal screw, and a plastic ring for the bearing outer ring.
• 6.4 Plastic container: as shown in Figure 2.
• 6.5 Running table: as shown in Figure 3.
• 6.6 Thrust loader: as shown in Figure 4 (the source text "as shown in Figure 4l" is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)).
• 6.7 Bearing greaser: as shown in Figure 5.
• 6.8 Hand pliers: as shown in Figure 6.
• 6.9 Syringe: capacity at least 100 mL±5 mL, equipped with a needle at least 100 mm long and at least No. 16.
• 6.10 Stopwatch: capable of measuring 60s±3s.
• 6.11 Oven: laboratory oven, vibration-free, capable of maintaining 52℃±1℃ (the source text "52[unreadable sign]1%" is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)).
• Figure 5a Bearing greaser (brass) marked dimensions (unit mm): drilled hole diameter 3.97; 12 equally spaced holes; bolt circle diameter 34.13; 10.0±0.79; 15.08; φ56.36; 49.43±0.08; 39.69; 38.10±0.76; 30.16; 43.18; 22.12; 38.10±0.08; R11.11; 44.45; φ76.20; 37.97; R7.94; 28.58; 25.10; 49.21. Note: unless otherwise specified, the specified tolerance is 0.076 mm.
• Figure 5b Bearing greaser (optional) parts: 1— greasing piston; 2— grease reservoir; 3—LM11900 bearing (as in the source, requires confirmation against the source standard (source-text extraction)); 4— column head; 5— base.
• Figure 4 Thrust loader markings: upper adjusting nut, lower adjusting nut, O type ring φ4.76, 53, 7.1, 70, 12; distance between the two end faces of the column 19.0; unit is millimeters.

6. Recommended operating conditions

• Running: run under light thrust load for 60s±3s.
• Exposure conditions: 52℃±1℃, 100% relative humidity, store for 24h±0.5h.
• Synthetic seawater concentration: various concentrations (0%, 5%, 10%, etc., see Chapters 10 and 13); dilute with distilled water to the required concentration (volume fraction).
• Synthetic seawater standing time: do not exceed one week.
• Oven: vibration-free, 52℃±1℃.
• Bearing drying: dry for 15 min at 74℃±5℃ (the source text "74t[unreadable sign]5CC[garbled preposition] dry for 15m" is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)).
• Solvent cleaning liquid temperature: freshly prepared about 66℃±5℃ (the source text "[garbled qualifier]66°5°C" is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)).

7. Sampling and specimen preparation

• 9 Bearing preparation:
  • 9.1 Carefully inspect the test bearing and select a bearing that is completely free of corrosion. During bearing preparation, use tweezers or wear rubber or plastic gloves; never touch the bearing directly with hands at any time.
  • 9.2 Clean the selected bearing with solvent oil heated to 52℃ (Note: flammable, vapor toxic) to remove the rust preventive, and scrub the bearing and bearing outer ring in the solvent with cotton yarn to completely remove residues. Clean the bearing again with fresh hot solvent oil. Note: The specified temperature should be lower than the flash point of the solvent oil. The cleaning operation should be carried out in a well-ventilated fume hood where there is no open flame or other ignition source.
  • 9.3 Take the bearing out of the solvent oil and place it into solvent cleaning liquid (Note: toxic, flammable, vapor highly irritating. If swallowed, fatal; inhalation causes injury) to remove the solvent oil and any possible fingerprints. Slowly rotate and clean the bearing in freshly prepared solvent cleaning liquid of about 66℃±5℃. Note: The freshly prepared solvent cleaning liquid is to avoid selective evaporation of components at the cleaning temperature.
  • 9.4 Take the bearing out of the solvent cleaning liquid, place it on filter paper to air-dry, then place the bearing into an oven and dry it at 74℃±5℃ for 15 min.
  • 9.5 Cool to room temperature and inspect its surface again to ensure that the selected bearing has no corrosion and can rotate freely (handle carefully, do not allow the bearing to rotate).
  • 9.6 Using the same method as for bearing preparation, clean and dry the bearing greaser (the original clause number is suspected to be "9.6", source-text extraction is unclear in the source text, requires confirmation against the source standard (source-text extraction)).
• 10 Test procedure (sample filling part):
  • 10.1 Place the grease reservoir end of the bearing greaser on a clean workbench, put on gloves, and insert the end face of the bearing outer ring with the smaller diameter downward into the groove of the bearing greaser. Place the bearing cone into the bearing outer ring so that the bearing assembly fits tightly against the bearing greaser, pick up the pin greaser of the bearing assembly, invert it, and place it on the workbench.
  • 10.2 Fill the grease reservoir with the grease sample, and use the greasing piston to press the sample into the bearing. Carefully remove the greasing piston from the grease reservoir, move the greaser to the edge of the workbench, keep the bearing assembly inside the greaser, and at the same time turn it over and place it on the workbench.
  • 10.3 Using a small square-head scraper, scrape off excess sample from between the bearing inner ring and the outside of the greaser and bearing outer ring. Remove the bearing from the greaser with pliers or gloved fingers. Scrape off excess grease from the outside of the bearing with the scraper; this operation is to ensure that the amount of grease taken each time is approximately the same.

8. Analysis procedure

• 8 Calibration of thrust loader:
  • 8.1 After operating as described in the test procedures from clause 10.1 to clause 10.4, install the bearing in the bearing holder and place the assembly into a plastic container. Place the plastic container on the base of the drive device so that it is at the center of the drive pointer. Lower the drive until the O type ring just contacts the 1 kg counterweight. Turn the lower adjusting nut of the depth gauge downward to the stop position (see Figure 3). Place a 3 mm spacing plate on top of this nut, turn the upper adjusting nut downward onto the spacing plate, and after the upper adjusting nut contacts the spacing plate, remove the spacing plate, keep the upper adjusting nut stationary, and turn the lower adjusting nut upward so that it is tight against the upper adjusting nut. When the depth gauge handle is pressed down, at this time there is about 29 N load, and the total load applied to the bearing is 39 N (these loads are provided by the spring pressure on the thrust loading shaft, the 1 kg counterweight, and the total weight of the spring. These loads are approximate. The accuracy of the 1 kg counterweight should be 0.010 kg. When the thrust loader is used for the first time, the spring should be calibrated and periodically rechecked; if the spring cannot provide sufficient force to maintain non-slip operation of the test bearing 60s and cannot achieve the purpose of distributing the grease sample, the spring needs to be replaced). Periodically inspect the O type ring; if there are any cracks or other signs of damage, replace the O type ring.
  • 8.2 The thrust loader shall be calibrated before use, and if used daily, calibrated once per day. If there is reason to believe that the standard calibration has changed, recalibrate. The thrust loader may be calibrated using a grease that has already been tested as a standard.
• 10.4 As shown in Figure 1, hold the bearing loaded with sample with both gloved hands, with the large inner diameter end of the bearing outer ring facing downward, insert the small-diameter plastic flange from the top end of the bearing, insert the large-diameter plastic flange from the bottom end of the bearing, move the bearing assembly onto the 1 kg counterweight, and the small-diameter plastic flange just enters the groove at the top of the counterweight. Insert the screw into the bearing assembly and tighten the screw to the counterweight. Place the bearing holder (see Figure 1 part 3) on top of the bearing (convex ring facing upward), and press down the bearing holder so that the bearing just enters the bearing holder.
• 10.5 Place the plastic container on the assembly, slide the plastic container to the edge of the workbench, press the top of the counterweight with fingers toward the inner bottom of the plastic container, and invert the assembly.
• 10.6 Place the plastic container on the base of the drive device so that it is at the center of the drive pointer, lock it, start the motor, and make the drive pointer enter the 1 kg counterweight, loading until the nut touches the bottom. Run for 60s±3s, turn off the motor, raise the drive shaft and let the bearing stop by inertia. In subsequent operating steps, be very careful not to disturb the contact between the bearing outer ring and the rollers. During operation or after running for 60s, do not smooth out or press the grease back into the bearing.
• 10.7 Prepare synthetic seawater according to the method in Appendix A, dilute with distilled water to the required concentration (volume fraction), and set aside for testing. The standing time of synthetic seawater should not exceed one week.
• 10.8 Use a clean syringe to draw 100 mL±5 mL of the prepared synthetic seawater. With the operated bearing already placed in the plastic container, begin injecting the synthetic seawater into the plastic container through the dedicated small hole on the bearing holder, and at the same time start the stopwatch, completing the addition of 100 mL synthetic seawater within 20s±3s. When the time reaches 60s±3s, begin withdrawing the synthetic seawater, and by 80s±3s, withdraw 70 mL±5 mL synthetic seawater, leaving 30 mL±5 mL synthetic seawater remaining in the plastic container. Ensure that after the water of 70 mL±5 mL is withdrawn, the remaining water does not contact the bearing.
• 10.9 Tighten the plastic container lid.
• 10.10 Three bearings are required for each concentration of diluted synthetic seawater for each grease. Every three bearings form one test group. Place in a vibration-free dark oven and keep at 52℃±1℃ for 24h (the original text "8 vibration dark oven" is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)).
• 11 Result evaluation:
  • 11.1 Take the bearing out of the container, place the bearing outer ring into a mixture of isopropanol (Note: flammable) and solvent oil (Note: flammable, vapor toxic) in a volume ratio of 50:50; the mixture may be heated to ensure complete removal of grease from the bearing outer ring. Shake vigorously to remove grease. Repeatedly clean with fresh mixture as above or wipe the bearing with a clean soft cloth or silk cloth to ensure removal of grease traces.
  • 11.2 Take it out of the isopropanol-solvent oil mixture and place it on clean filter paper to air-dry.
  • 11.3 Inspect the bearing outer ring raceway for signs of corrosion without using a magnifying glass (see Chapter 5), and evaluate as pass or fail. Count by spots; if any spot of 1.0 mm or larger appears, it is judged as fail. The number of spots is not counted.
  • 11.4 Lightly wipe the stain at the spot with dry cotton yarn (dry or wetted with any solvent that does not react with rust marks or steel at room temperature); it is not considered corrosion in the judgment (the original clause number is suspected to be 11.4, source-text extraction is unclear in the source text, requires confirmation against the source standard (source-text extraction)).

9. Qualitative and quantitative and calculation formulas

• This method is a qualitative evaluation (pass/fail); no calculation formula is provided in the available source.
• Result evaluation rule: Count by spots; if any spot of 1.0 mm or larger appears, it is judged as fail; the number of spots is not counted.
• Stain judgment: If the metal surface is still visible under the stain, the stain is not considered corrosion in this standard and shall be ignored; lightly wipe the stain at the spot with dry cotton yarn (or cotton yarn wetted with a solvent that does not react with rust marks/steel); it is not considered corrosion in the judgment.
• Final result: At the specified concentration of diluted synthetic seawater, the result that is the same for at least two of the three bearings is the final result (in the original Chapter 12, at "[truncated agreement wording]" the text source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction)).

10. Precision

• 13.1 Repeatability: It can be judged based on the following fact: in one laboratory, using 8 samples at 4 synthetic seawater concentrations (0%, 5%, 10%, 100%), at least 2% of the repeated results obtained are consistent (the original text "[garbled qualifier]2%" is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)).
• 13.2 Reproducibility: It can be judged based on the following fact: in 6 laboratories, using 8 samples at 4 synthetic seawater concentrations (0%, 5%, 10%, 100%), at least 77% of the reported results of pass or fail for corrosion resistance are consistent (the original text "at least [garbled character]77%" is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)).
• 13.3 Bias: Since the test results are only judged as pass or fail according to the acceptance criteria specified in the method, this method does not specify bias.
• Note: In the original Chapter 13, the clause numbers source-text extraction are shown as "13", "13.1", "13.2", "13.3", etc.; some numbers are incomplete, requires confirmation against the source standard (source-text extraction).

11. Report

• 12 Report: Use pass or fail as the determination result; the final result is the result that is the same for at least two of the three bearings at the specified concentration of diluted synthetic seawater (in the original Chapter 12, the text source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction)).
• Report content: A more detailed list of report elements is not provided in the available source.

12. Normative references

• GB 1922 Solvent oil for paints and cleaning
• GB/T 5018 Test method for corrosion preventive properties of lubricating grease
• GB/T 6682 Water specifications and test methods for analytical laboratories (GB/T 6682-1992, neq ISO 3696:1987)
• ASTM D5969-05 (the original standard modified and adopted)

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