ASTM D6973 Standard Test Method for Indicating Wear Characteristics of Petroleum Hydraulic Fluids in a High Pressure Constant Volume Vane Pump
14. Report
14.1 Report the following information:
14.1.1 Mass loss of the ring and vanes in milligrams (mg).
14.1.2 Flow rate at the start and end of the test.
14.1.3 Any unusual observations on wear, scuffing, deposits, cavitation damage, deterioration of seals, and bushing replacement.
14.1.4 Fluid cleanliness at the start and end of the test.
14.1.5 List any modifications to the test method procedure, conditions, or apparatus, and report as "A Modification to Test Method D6973".
15. Precision and Bias
15.1 The precision of this test method is based on an interlaboratory study conducted in 2006. Each of five laboratories tested three different materials in triplicate. Every test result represents an individual determination. For Materials A and B, one laboratory reported only duplicate results. See Table 1.
15.1.1 Repeatability - Two test results obtained within one laboratory shall be judged not equivalent if they differ by more than the "r" value for that material; "r" is the interval representing the critical difference between two test results for the same material, obtained by the same operator using the same equipment on the same day in the same laboratory.
15.1.2 Reproducibility - Two test results shall be judged not equivalent if the differ by more than the "R" value for that material; "R" is the interval representing the difference between two test results for the same material, obtained by different operators using different equipment in different laboratories.
15.1.3 Any judgment in accordance with these two statements would have an approximate 95 % probability of being correct.
15.2 Bias - At the time of the study, there was no accepted reference material for determining the bias for this test method, therefore no statement on bias is being made.
15.3 The precision statement was determined through statistical examination of 43 results, from five laboratories, on three materials. The requirement of six participating laboratories, as found in Practice E691, was not met for this study.
15.3.1 The three materials tested were at various levels of performance and were identified as follows:
Material 1: mineral zinc-based hydraulic fluid
Material 2: mineral zinc-based hydraulic fluid
Material 3: mineral zinc-based hydraulic fluid
15.3.2 To judge the equivalency of two test results, it is recommended to choose the material closest in characteristics to a test material.
16. Keywords
16.1 hydraulic fluid; vane pump; wear
