The effectiveness evaluation of 314L stainless steel vibratory stress relief by dynamic stress

Vibratory stress relief (VSR) is a procedure to reduce the residual stress by means of vibrating dynamic stress. Currently, real-time and quantitative evaluating the effectiveness of VSR is an important problem. Cyclic loading, or dynamic stress, imposed on the welded structure during VSR affect the reduction of residual stresses directly. This paper examines the cyclic stress and strain of type 304L stainless steel welded specimens and presents the cyclic creep mechanism during VSR of 304L. According to the experiments, a mathematic model of residual stress relaxation proposed which conducted against dynamic stress. The model is applied to evaluate the effectiveness of VSR during manufacturing HT-7U Tokamak welded structure. The difference of residual stress decrease between the calculated and measured is about 11%. The result shows that the effectiveness evaluation of VSR using dynamic stress is practical.