Vibration conditioning of metals is the alternative to classical thermal stress relief

Abstract

The existence of residual stresses caused by the welding process is an important reason of cracking and distortion in welded metal structures that may affect the fatigue life and dimensional stability significantly. Heat treatment is one of the traditional methods to relieve the residual stresses. But it is often limited by the manufacturing condition and the size of the structures. In this article a procedure called vibratory stress relief (VSR) is discussed. VSR is a process to reduce and redistribute the internal residual stresses of welded structures by means of post-weld mechanical vibration. The effectiveness of VSR on the residual stresses of welded structures, including the drums of hoist machine and thick stainless steel plate are investigated. Parameters of VSR procedure are described in the article. Residual stresses changes on weld bead are measured before and after VSR treatment by metal magnetic memory method. Several specimens, after welding and vibratory treatment, were cut off the welded plates and submitted for tensile, impact, hardness tests and metallographic analysis.