GEARBOX PROTECTION

FZG GEAR TESTING (ASTM D5182): Evaluation of scuffing load capacity of lubricants.

The FZG (Forschungsstelle für Zahnrader und Getriebebau) test evaluates fluid lubricating and wear protection properties at the interface of a loaded set of gears. The gears are operated at 1450 rpm through 12 progressive load stages (max load of 534.5 Nm) at 15 minute intervals with a fluid temperature stabilized at 90°C (194°F).

For additional performance, two extended stages have been checked to go up to stage 14 with a torque of 714.2 Nm. Gear teeth are inspected after each load stage for scu ing, to visually detect scratches on the pinions. Lubricants are then graded based on their “Failure Load Stage” or FLS rating from FLS 1 (very poor result) up to FLS 14 (outstanding result).

This test checks if adequate lubrication film thickness has been built between the gears for gearbox reliability.