AGMA 06FTM07 PDF

Micropitting and pitting are fatigue failures that occur on case carburized gears. The performance of lubricants in regard to micropitting and pitting can be evaluated by test methods. The FVA-FZG-micropitting test consists of two parts: a load stage test followed by an endurance test. The tests require relatively high costs and are time consuming. Therefore an analogous short test method was developed to classify candidate lubricants, and supplement the existing test. The results of the short test method are given. The FVA-FZG-pitting test is for limited-life using test gears, which are ground without controlled profile or helix modifications. Although the flank roughness is restricted, the appearance of micropitting can cause a wide statistical spread of pitting test life. Thus, there was potential improvement in the test results reproducibility. In the test gears were superfinished to prevent micropitting, and given flank modifications for improved test relevance. The paper describes test procedures and shows basic examples of test results.