The Effect of Elevated Temperature Exposure on Residual Stresses

Shot peening is commonly used to create residual compressive stresses in part surfaces, thereby reducing the effects of tensile service loads and improving fatigue life.

The research reported here was initiated to determine whether or not the residual compressive peening stresses are rapidly annealed out by elevated temperature exposures. AISI H-11 and 52100 steels were selected for the tests, peened, and subjected to temperatures up to 800° F for times to 4000 hours. Residual stress measurements were made by X-ray diffraction methods.

It was shown that residual stresses are not significantly relieved in 52100 within 10 hours at 400° F, or 4000 hours at 300°F. For H-11, no change was produced within 10 hours at 800° F or 4000 hours at 600° F. It was found possible to relate the reduction in initial residual compressive stress level caused by thermal stress-relief by a parameter of the form P = T (c + log t).