Eckert, E. J.
Supervising Engineer, Caterpillar Tractor Co., Peoria, Ill.
Pages: 16 Published: Jan 1958
Unidirectional torsional fatigue tests were run on axle shafts with an average shank diameter of 3 in. Since the main interest was in the performance of these shafts in the low cycle range, it was necessary to design and build a hydraulic, non-rotating, constant load fatigue machine for this purpose. The construction and operation of this machine are described. The effect of various surface conditions and hardness was investigated. A comparison was made with published literature to indicate size effect. Supplementary tests were run to determine the stringer content, hardness profile, chemical composition, and shot peening intensity. Materials tested were SAE 86B45H and SAE 4150 steels at Rockwell hardness C 45 or above. It was found that inclusions lowered and shot peening increased the fatigue strength of these shafts. Straightening produced no significant influence. The maximum strength in the shank was obtained with a Rockwell hardness of C 50 to 55. The fatigue strength was found to be somewhat less than that of smaller specimens in published literature.
Paper ID: STP45762S