Failure analysis of liquid-nitrided low carbon steel gears

The results of experimental investigations of hobbed and low temperature liquid-nitrided low carbon steel gears conducted in a back-to-back gear test rig are presented. Scanning electron microscopy and optical microscopy studies were carried out to understand the nature of the failures. Ferrographic analysis of the lubricating oil gave a good correlation with the observed data. An extensive programme of testing is necessary before a definite conclusion can be drawn about the prediction by ferrography of the onset of gear failure. © 1984.