Improvement in Resistance to Bending Fatigue: Prestress Shot-Blasting of Case-Hardened Steel Gearing

Author:  Couratin, D; Guimier, A
Source:  Galvano-Organo- Traitements de Surface pp439-444 May 1990
Doc ID:  1990116
Year of Publication:  1990
Abstract:  
For many years prestress shot blasting has been used to improve fatigue limits in steel (e.g. 16CD4). It was used originally for springs and the improvements suggested the process might be adapted for pinions and gears where a high surface residual stress could improve their lives. Peening tests were made using both round and irregularly shaped steel and irregularly shaped corundum at temperatures between ambient and 140 deg C. It was found that the corundum was most effective, irregularly shaped steel was better than round, the angle of blasting was very important especially at the root of the teeth, and temperatures up to 80 deg C do not have any effect on residual stresses. The major problem with corundum was that it increased surface roughness.