The Effect of Welding Parameters on Residual Stress in Butt-Welded Joints

Abstract

Welding is a crucial manufacturing process for joining materials to create durable structures. However, it introduces residual stresses that can affect the structural integrity and performance of welded joints. These stresses, resulting from localized heating and cooling, can cause distortions, reduced fatigue life, and stress corrosion cracking, compromising the reliability of welded components. This thesis examines the effect of different welding parameters on residual stress in butt welded joints using the finite element analysis software ANSYS. Key parameters studied include welding speed, heat input, and cooling rate, which significantly influence the thermal cycles and mechanical properties of welded joints. The materials and methods investigated are high-strength aluminum alloy with thin plates under hybrid high-speed gas fluid, duplex stainless steel with A-TIG welding, AISI 1045 plate with varying welding speeds, aluminum 2519 and aluminum 2319, and a case with different bevel angles. The primary objective is to understand how variations in these parameters affect the distribution and magnitude of residual stresses. A comprehensive literature review establishes the theoretical foundation and identifies critical parameters affecting residual stress. The methodology involves setting up a detailed simulation model in ANSYS, incorporating accurate geometric representations, material properties, and boundary conditions. The double-ellipsoidal heat source model is used to simulate the welding heat input realistically. Simulation results provide insights into temperature distribution, residual stress distribution, and deformation patterns in butt-welded joints. Higher welding speeds result in lower heat input and faster cooling rates, leading to higher residual stresses. Conversely, lower welding speeds lead to higher heat input and slower cooling rates, resulting in lower residual stresses. Similarly, higher heat input and faster cooling rates are associated with increased residual stresses due to the larger heat-affected zone and rapid thermal contraction. The findings highlight the importance of optimizing welding parameters to minimize residual stresses, enhancing the performance and longevity of welded structures. ANSYS proves effective for simulating and analyzing the welding process, providing valuable insights for improving welding practices. The study concludes with practical recommendations for minimizing residual stress through optimal parameter selection and suggests directions for future research. This research contributes to welding engineering by providing a analysis of the effect of welding parameters on residual stress, supported by simulation data.