: X-ray diffraction data to evaluate the welding residual stresses variation in welded joints under cyclic loads

This article presents the results for the measurement of the residual stresses by means of X-ray diffraction in butt-welded specimens subjected by cyclic loads. To do it a procedure was proposed and a study case was developed. The material studied was AISI 1018 steel. The process used to join the plates was semiautomatic welding. Residual stresses were measured at zero, 2 500, 5 000, 7 500 and 10 000 load cycles respectively. For this a diffractometer XRD; PANalytical Empyrean model was utilized to obtain a residual stresses and a MTS810 servohydraulic testing machine to mechanical test. The mechanical characterization of the joint was performed to determine the parameters of the fatigue load cycle. The residual stresses were measured before starting to apply the cyclic loads and subsequently they were measured again every 2 500 load cycles. As the main result of the application of this procedure to the joint studied, it was obtained that in the analyzed position, the residual stresses were compression and increased in absolute value with the action of the cyclic loads. For each diffractometric are showed a data of the position and the light intensity. Also are showed the incidence angle and the distance between adjacent lattice planes.