Trapped Stresses

Author:  Fuchs, H. O.
Source:  Machine Design, July, 1948, p. 114
Doc ID:  1948006
Year of Publication:  1948
Abstract:  
Most designers and all good shop men are aware of quench cracks and of the distortions which accompany welds. As is well known, such cracks and distortions are caused by stresses set up within a piece when one part cools more rapidly than another. As a result of this knowledge, stress relief annealing is often specified for complicated weldments and castings, and special high temperature quenching is used in heat treatment. Only in the last few years has the knowledge of this type of stress, which may best be called "trapped stress" but is also know as residual stress, been applied conciously to serve a useful purpose. Trapped stresses, deliberately produced by heat treatment, shotpeening, overstressing or other methods, help to carry loads and to increase the strength of parts against static and especially fatigue failure.