Distortion and residual stresses in thick plate weld joint of austenitic stainless steel: Experiments and analysis

In the present study, the distortion induced in rectangular plate of AISI 304 SS during autogenous GTA welding process is measured experimentally and further validated using Finite element (FE) analysis. The thermal histories are measured at fixed locations over the surface of the plate and the results are compared with FE analysis. The Gaussian surface and Volumetric heat source models are simulated and transient heat transfer analysis is performed. The heat source models have been tested with two different speeds. The effectiveness of change in thermal histories of the heat sources have been studied and reported. In FE analysis, the sequentially coupled thermomechanical analysis is performed using the thermal histories as input and the distortion of the plates are predicted and compared with experimental measurements. The large and small displacement theories are employed for the above purpose and the effectiveness of the theories are reported. The edge deformation of the plates have been measured and validated for both the theories. The residual stress and distortion at the mid span are predicted and discussed. The results predicted using large displacement theory is in good agreement with measured values.

3D finite element simulation of temperature distribution, residual stress and distortion on 304 stainless steel plates using GTA welding

Numerical simulation of multi-pass GTA welding of grade 91 steel

Welding residual stresses can predominantly damage the reliability and performance of the welded structures. In this experimental study the effect of constant and pulse arc TIG welding processes, the development of thermal fields and residual stresses in dissimilar weldments of SS 316 and Monel 400 are investigated. During the welding process, the temperature distribution over the surface of the weldments has been captured using Infra-Red Thermography. The developed residual stresses have been measured experimentally by using the x-ray diffraction technique. The nature of residual stresses in constant and pulse arc weldments have been observed and compared. The experimental results of constant current weldments are validated against finite element analysis using ANSYS software. Transient thermal analysis is performed to determine heat dissipation during the welding process in different modes such as conduction, convection and radiation. Also, the elemental birth and death techniques are considered for the effect of filler wire owing simulation. From the results, the experimental and numerical analysis of constant arc welding process show good agreement to each other in temperature fields and residual stresses.

https://iopscience.iop.org/article/10.1088/2053-1591/ab23cf/pdf

Thermal fields and residual stresses analysis in TIG weldments of SS 316 and Monel 400 by numerical simulation and experimentation

Currently, welding processes have become one of the most used methods for joining materials in all kinds of industries, thanks to properties such as high speed and high tensile strength. However, despite these advantages, this type of connection method has some drawbacks, for example, residual stress and structural distortion, mainly due to the process thermal cycles. Structural distortion is one of the major concerns of industrial joining practice. In order to decrease distortion, the variation of welding sequence, direction, and clamping conditions, have been applied through several years, by trial and error tests. However, numerical simulation enables virtual examination of the welding, mainly due to the progress on the numerical methods, which stimulated the research on welding simulation models. These models can cover a wide spectrum of physical and thermal processes occurring during, and after welding. The aim of this paper is to provide wider information about types of finite element method (FEM) in fusion welding processes and to demonstrate the accuracy of FEM models results compared to experimental.

https://www.mdpi.com/2075-4701/10/1/75/pdf

Comparison of Finite Element Methods in Fusion Welding Processes—A Review

In this paper, investigation of residual stress and distortion induced in 3 mm thick Modified 9Cr-1Mo steel plates during GTA welding is carried out. SYSWELD software is used for the thermo-mechanical analysis. A 3D meshed model is created for the simulation and double ellipsoidal heat source distribution is used for the thermal analysis. Thermal cycles predicted near the fusion zone are compared with experimentally measured thermal cycles using thermocouples. Predicted residual stress profile across the fusion zone is compared with the measured profile using X-ray diffraction method. There is a good agreement between measured and predicted thermal cycles and residual stress profile. Distortion of the weld joint is measured using vertical electronic height gauge. Finite element analysis of distortion of the weld joint is carried out by applying both large and small distortion theories. Comparison of experimental and numerical results showed better accuracy if large distortion theory is applied.

Vilas Chaudhari

Papers

Experimental and finite element analysis of residual stress and distortion in GTA welding of modified 9Cr-1Mo steel