Pitting Resistance of Some High Temperature Carburized Cases

Surface type gear pitting failures were produced on a geared roller test machine and the pitting life data was statistically analyzed by a method that accounts for or minimizes the influence of variables that determine the fatigue environment. The sensitivity of pitting fatigue failures to microstructure is demonstrated. Rollers were carburized at three elevated temperatures, including vacuum carburizing at 1900°F. Direct quench coarse grain rollers had significantly lower pitting life. Pitting life increased when rollers were reheated after carburizing for grain refinement.