Thermo-mechanic and Microstructural Analysis of an Underwater Welding Joint

Abstract

Abstract:The aim of this research is to present a comparative analysis between theoretical and experimental thermal fields as well as a microstructural behaviour and residual stresses applying multiple weld beads in the joint of two API 5L X52 pipe sections. The thermal field, microstructural and residual stresses were numerically modelled through the finite element method (FEM) and compared to experimentally. The simulation conditions used in the FEM analysis were similar considerations to the underwater welding conditions. The finite element analysis was carried out, first by a non-linear transient thermal analysis for obtaining the global temperature history generated during the underwater welding process. Subsequently, a microstructural behaviour was determined using the temperatures distribution obtained in the pipe material by calculating the structural transformations of the material during the welding process, and finally a stress analysis was developed using the temperatures obtained from the thermal analysis. It was found that this simulation method can be used efficiently to determinate with accuracy the optimum welding parameters of this kind of weld applications.Key-words: API 5L X52; Finite element analysis; Residual stresses; Temperature field; Underwater welding. Análise Termo-mecânica e Microestrutural da União Soldada Durante Soldagem SubaquáticaResumo: O objetivo deste trabalho é apresentar uma análise comparativa entre os campos térmicos teóricos e experimentais, bem como um comportamento microestrutural e as tensões residuais aplicando cordões em solda multipasses na união de duas seções de tubo API 5L X52. O campo térmico, as microestruturas e as tensões residuais foram numericamente modelados através do método por elementos finitos e comparados com o experimental. As condições de simulação utilizadas na análise por elementos finitos foram consideradas semelhantes às condições de soldagem subaquáticas. A análise por elementos finitos foi efetuada, primeiramente uma análise térmica transiente não linear para obter a evolução da temperatura global gerada durante a soldagem subaquática. Depois, um comportamento microestrutural foi determinado usando a distribuição de temperaturas obtida no material do tubo calculando as transformações estruturais do material no processo, e, finalmente, uma análise de tensões foi desenvolvida utilizando as temperaturas obtidas a partir da análise térmica. Foi encontrado que este método pode ser utilizado eficientemente para determinar com precisão os parâmetros de soldagem ótimos neste tipo de soldagem por simulação.Palavras-chave: API 5L X52; Análise de elementos finitos; Tensões residuais; Campo de temperatura; Soldagem subaquática.

Mild Steel GMA Welds Microstructural Analysis and Estimation Using Sensor Fusion and Neural Network Modeling

“…They calculated the microstructure evolution of the weld pool through the macro-micro coupling cellular automaton-finite different (CA-FD) method and obtained good results comparing with experiments carried out by GTA welding. A comparison between theoretical and experimental thermal fields as well as microstructural behavior and residual stresses applying multiple weld beads in the joint of two API 5L X52 pipe sections was conducted by [ 23 ]. The results showed that the simulation method can be used efficiently to determinate with accuracy the optimum welding parameters of this kind of weld application.…”

Effect of Plasma Arc Welding on Residual Stress and Distortion of Thin Titanium Sheet

“…High localized heat transfer and strong non-uniform temperature field during the heating and cooling cycles makes non-uniform thermal expansion and contraction which results in inhomogeneous plastic deformation in the weld metal and its surrounding. This leads to formation of residual tensile and compressive stresses in the work piece due to the uneven heating and cooling [7][8][9] . The presence of tensile residual stress is the cause for reduction in fatigue strength and further compressive residual stress will diminish the stability limit of the material 10,11 .…”

Temper Bead Welding of S420G2+M Steel in Water Environment

“…Water as welding environment causes a lot of problems with the quality of obtained joints and their mechanical properties. Transferring the welding process to water environment results in: increasing cooling rate, increasing diffusible hydrogen content in deposited metal, formation of residual stresses and worse arc stability [11][12][13][14][15].…”