WEAR CHARACTERISTICS OF TRACTOR HYDRAULIC FLUIDS: ASTM D4998
EXPLANATION
Many modern tractor designs use hydraulic fluid to lubricate the transmission and final drive gears. This test method is used to screen the suitability of the tractor hydraulic fluids for gear wear. Although primarily applicable for tractor hydraulic fluids, it may be suitable for other applications.
TEST SUMMARY
A modified FZG gear oil test machine is operated for 24 h under controlled conditions of speed (100 r/min), load (tenth stage), and temperature (121° C). Test gears are lubricated with the test oil. The test gears are weighed and visually examined before and after the test. The gear weight loss and the visually observed damage to the gear teeth are used to evaluate the wear obtained with the test fluid.
TEST PRECISION
Repeatability: 27.4 mg
Reproducibility: 43.2 mg
There is no bias.
