Prestressing Processes and Fracture Barriers

Author:  Almen, J.O.
Source:  Product Engineering, March 1951, pgs. 101-124
Doc ID:  1951003
Year of Publication:  1951
Abstract:  
Unexpected and unrecognized improvement in fatigue strength of metal products is often obtained from processes that are applied for other purposes. Engineers, often unknowingly, have long made use of the fact that fatigue fractures cannot originate and cracks cannot propagate in compressively stressed material. Railway car wheel failures would be more frequent if fatigue barriers, in the form of residual compressive stresses, were not present in the rims of the wheels. These essential stresses are induced during fabrication by operations that are intended to harden the wheel surfaces and thus obtain wear resistance.