Technical Committee Lubricants

Development of a short duration pitting test to evaluate the lubricant influence on the pitting carrying capacity of spur gears

The pitting test methods according to FVA 2/IV and FVA 371 were developed to determine the lubricant influence on the pitting carrying capacity of gears. These test methods provide comprehensive information, but they are relatively time-consuming and cost-intensive. An efficient short test procedure, as screening test to differentiate several lubricants regarding their pitting resistance, was missing so far.

In this research project the DGMK short duration pitting test was developed and tested with lubricants, whose pitting carrying capacity is well known from the existing pitting tests.

The DGMK short pitting test categorizes candidate lubricants regarding their pitting resistance in the load-carrying capacity classes low, medium and high. The test procedure requires approx. 2 weeks for this. The determined load-carrying capacity classes correlate well with results of the pitting test methods according to FVA 2/IV and FVA 371, although a possible influence of micropitting on the pitting lifetime in the test FVA 2/IV has to be considered.

The DGMK short duration pitting test represents a suitable short test procedure, which differentiates lubricants regarding their pitting carrying capacity with good repeatability and with a shortened test duration. This test procedure is to be seen primarily as a supplement to the existing FVA pitting test methods.