Variation of residual welding stresses during the action of cyclic loads

Abstract

Residual stresses influence the fatigue behavior of the welded joint. The aim of this work is to measure the welding residual stresses using X-ray diffraction in a position close to the heat-affected zone of a butt weld of AISI 1015 steel subjected to cyclic loads. To achieve this, a procedure was proposed and developed for this case study. Mechanical tests were performed on an MTS810 universal testing machine, while the residual stresses were measured with an diffractometer PANalytical model Empyrean. The fatigue load cycle parameters were determined. In order to know the range in which the measurement of residual stresses should be conducted, a sample of the base material was first tested. Residual stresses were measured before starting to apply the cyclic loads and were subsequently measured again every 2,500 loading cycles. As a main result of applying this procedure to the studied joint, it was found that at the analyzed position, the residual stresses were in compression and increased in absolute value with the action of the cyclic loads.