Defects and residual stresses effect on the functional performance of a 106 pipes after the welding process

Abstract

Abstract Producing soundness weldments is the main goal to avoid catastrophic failures that occur in oil refineries, where the interaction of internal defects and residual stress with the working conditions leads to human and financial losses. AISI 1020- A106 carbon steel pipes that are used for oil products transmitted inside oil refineries have a 55 mm inner diameter with a 5 mm thickness and had been welded with shielded metal arc welding (SMAW) for the first samples group, while the second group was welded using gas tungsten arc welding (GTAW) process. For surface defects detection the liquid penetration method was used, while for internal defects radiography method was used, and for residual stresses X-ray diffraction was used. The results showed that the first group of samples contained different types of internal defects with compressive residual stresses, while the second group was nearly clear of internal defects with tensile residual stresses.