X-RAY ANALYSIS OF RESIDUAL STRESS DISTRIBUTION IN WELD REGION, J.T. Assis, V. Monin, J.R. Teodosio, T. Gurova, pp. 225-231

Distribution of residual stresses arising after welding is quite complex and inhomogeneous. Many factors have influence on the magnitude and the profile of the stress distribution curve. In the present paper an x-ray technique was used to analyze the residual stress distribution in steel sheets jointed by industrial welding with linear or circular weld seams. Interpretation of experimental results takes into consideration the satisfaction of the equilibrium equation. It has been shown that the equilibrium equation for residual stresses on the surface of a welded sheet, especially for stress components perpendicular to the weld seam, excludes the possibility of homogeneous stress distribution into the depth of the weld region. To confirm this point of view, stress measurements were made after successive removing of surface layers. INTRODUCTION Welding is one of the most important technological process used in many branches of industry such as industrial engineering, shipbuilding, pipeline fabrication among others. Residual stresses arising after welding exert a considerable influence on the service characteristics of welded equipment and their control allows to avoid failure of welded joint. The influence of residual stresses on service characteristics of welded equipment is analysed in many original papers and books [1,2]. Different techniques are used to control the stress state in the weld region. X-ray diffraction technique is one of the methods widely used to analyse residual stress distribution in weld seam and near the welded region. However, numerous measurements by X-ray tensometry [3,4] contain contradictory information about weld-induced residual stresses and the analysis of stress distribution is usually carried out without considering of equilibrium conditions. In this paper, experimental results of residual stress measurements by X-ray tensometry are presented. Both longitudinal and transverse stress components were made in the seam weld, the heat-affected zone (HAZ) and in the base metal near the weld region. Copyright (c)JCPDS-International Centre for Diffraction Data 2002, Advances in X-ray Analysis, Volume 45. 225