The Effect of Case Carbon Content and Heat Treatment on the Pitting Fatigue of 8620 Steel

The pitting fatigue of carburized 8620 steel in lubricated concentrated contact has been investigated over a range of case carbon contents (0.72-1.2%) and after direct quench and re-heat treatments. Several surface finishes were used, including the as-heat treated surface, ground finishes, and polished finishes. Testing was carried out on geared roller test machines.

Surface finish was found to be the variable having the most pronounced effect on fatigue resistance, the as-heat treated surface having the greatest resistance to pitting failure. Pitting fatigue also decreases with increase of case carbon content.