ASTM D4289 for elastomer compatibility of lubricating greases and fluids
11. Report
11.1 Report the following information for each compatibility test:
11.1.1 Date of test.
11.1.2 Sample identity.
11.1.3 Elastomer identity (including date of manufacture or batch number, or both), initial Durometer-A hardness, and initial density or relative density.
11.1.4 Test temperature and duration.
11.1.5 Hardness change to the nearest whole Durometer A unit, including the plus or minus sign. If replicate tests were run, report individual values as well as the mean.
11.1.6 Volume change, percent, to one decimal place for values >10 and to two decimal places for values <10. If replicate tests were run, report individual values as well as the mean.
12. Precision and Bias
12.1 Precision - Six cooperators tested six greases and three oils with two reference elastomers in a cooperative program conducted in accordance with the design-of-experiments. All tests were run in duplicate. The total range of results were (1) from 0.0 to 49.6 % volume change, and (2) from -20 to +1 Durometer A points.
12.2 The precision of the changes in volume and hardness as determined by this test method were obtained according to guidelines currently accepted by Committee D02 (Computer program: D2PP, Calculation of Precision Data: Petroleum Test Methods). Hardness-change precision values have been rounded to nearest 0.5 points.
NOTE 12 - For D4289–94 and earlier versions, the precision was calculated according to RR: D02-1007.13 When D02 Precision Program (D2PP) was released, precision values were recalculated (from the original test results) because D2PP results in the rejection of fewer data values. Test Method D4289–95 includes precision calculated with the (D2PP). When SAE Reference Elastomers AMS 3217/2B and AMS 3217/3A were adopted, the precision was determined with D2PP from results of a cooperative program conducted in 1995. These precision values are part of the current test method. Details of the test programs, test data, and statistical calculations from the earlier version, as well as the current version, are filed at ASTM Headquarters.
12.3 The precision of the mean changes in volume and Durometer A values as determined by statistical examination of the results of an interlaboratory test program is as follows:
12.3.1 Repeatability - The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of this test method, exceed the following values in only one case in twenty.
12.3.1.1 Reference Elastomer AMS 3217/2B (NBR-L) at 150°C:
Repeatability of volume change: 0.84 percentage points
Repeatability of hardness change: 1.5 Durometer A units
12.3.1.2 Reference Elastomer AMS 3217/3A (CR) at 100°C:
Repeatability of volume change: 1.41 percentage points
Repeatability of hardness change: 1.5 Durometer A units
12.3.2 Reproducibility (R) - The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values in only one case in twenty.
12.3.2.1 Reference Elastomer AMS 3217/2B (NBR-L) at 150°C:
Reproducibility of volume change: 3.45 percentage points
Reproducibility of hardness change: 11.5 Durometer A units
12.3.2.2 Reference Elastomer AMS 3217/3A (CR) at 100°C:
Reproducibility of volume change: 9.87 percentage points
Reproducibility of hardness change: 4.5 Durometer A units
NOTE 13 - The precision of this test method was determined with data obtained by six laboratories. Six greases and three fluids, covering a wide range of characteristics, were tested for compatibility with SAE Reference Elastomers AMS 3217/2B (NBR-L) and AMS 3217/3A (CR). With AMS 3217/2B (NBR-L) at 150°C, the volume change results obtained with the nine samples ranged from about 0 to 25 %, and the hardness change results ranged from -20 to +1 Durometer A units. With AMS 3217/3A (CR) at 100°C, the volume change results ranged from about 4 to 50 %, and the range of hardness change was from -22 to -4 Durometer A units.
12.4 The precision values apply only to SAE Reference Elastomers, AMS 3217/2B (NBR-L) and AMS 3217/3A (CR). The precision is expected, but not known, to be similar when other elastomers are used.
NOTE 14 - A summary of round-robin results obtained with reference lubricants and reference elastomers is provided for information purposes in Appendix X1.
12.5 Bias - The evaluation of compatibility of lubricating greases and fluids with elastomers by this test method has no bias because the values for volume change and hardness change can be defined only in terms of the test method.
13. Keywords
13.1 compatibility; density; elastomer; fluid; grease; immersion; lubricant; lubricating grease; relative; rubber; seal(s)
