SONIC SHEAR STABILITY OF HYDRAULIC FLUID: ASTM D5621
EXPLANATION
This test method permits the evaluation of shear stability with minimum interference from thermal and oxidative factors that may be present in some applications. It is applicable to fluids containing both readily sheared and shear-resistant polymers. Correlation with performance in the case of hydraulic application has been established.
TEST SUMMARY
Hydraulic fluid is irradiated in a sonic oscillator for a period of time and the change in viscosity is determined by Test Method ASTM D445. A standard reference fluid containing a readily sheared polymer is run frequently to ensure that the equipment imparts a controlled amount of sonic energy to the sample.
TEST PRECISION
Repeatability: 0.38 cSt
Reproducibility: 0.60 cSt
The bias of this test method has not been determined.
