scholarly journals Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine-Grained Steel

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Dezheng Liu ◽  
Yan Li ◽  
Haisheng Liu ◽  
Zhongren Wang ◽  
Yu Wang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cross Section ◽  
Material Flow ◽  
Welding Process ◽  
Weld Bead ◽  
Welding Residual Stress ◽  
Element Analysis ◽  
Ultrafine Grained ◽  
Solidification Cracks

Weld solidification crack prevention in the laser penetration welding process is essential for the strength of the welded component. The formation of solidification cracks can ultimately be attributed to welding residual stresses, and preventive measures should be taken during welding. In this study, the effects of residual stresses on the laser penetration welding quality of ultrafine-grained steels were investigated. A heat source model was established through the analysis of the metallography of the cross section of the heat-affected zone (HAZ) of ultrafine-grained AN420s-grade steel, and the chemical composition of the weld bead was obtained using an FLS980-stm Edinburgh fluorescence spectrometer. Furthermore, the constitutive coupling relation between the temperature and material flow stress was established based on the Gibbs function, and the welding residual stress was obtained by setting trace points in a finite element analysis (FEA) model based on experimental data of the weld bead cross section under different welding conditions. The results show that weld solidification cracks will form when the residual stresses exceed the material flow stresses in the weld bead, and the residual stresses can be decreased through a reasonable increase of the welding speed. The results indicate that the proposed criterion has high accuracy and can be used to predict the formation of weld solidification cracks in the laser penetration welding process.

scholarly journals Validation of Welding Simulations Using Thermal Strains Measured with DIC

2011 ◽  
Vol 70 ◽  
pp. 129-134 ◽  
Author(s):  
Maarten De Strycker ◽  
Pascal Lava ◽  
Wim Van Paepegem ◽  
Luc Schueremans ◽  
Dimitri Debruyne
Keyword(s):  
Residual Stresses ◽  
Cross Section ◽  
Circular Cross Section ◽  
Welding Process ◽  
Weld Bead ◽  
Image Correlation ◽  
Steel Tubes ◽  
Element Analysis ◽  
Strain Evolution ◽  
The Cross

Residual stresses can affect the performance of steel tubes in many ways and as a result their magnitude and distribution is of particular interest to many applications. Residual stresses in cold-rolled steel tubes mainly originate from the rolling of a flat plate into a circular cross section (involving plastic deformations) and the weld bead that closes the cross section (involving non-uniform heating and cooling). Focus in this contribution is on the longitudinal weld bead that closes the cross section. To reveal the residual stresses in the tubes under consideration, a finite element analysis (FEA) of the welding step in the production process is made. The FEA of the welding process is validated with the temperature evolution of the thermal simulation and the strain evolution for the mechanical part of the analysis. Several methods for measuring the strain evolution are available and in this contribution it is investigated if the Digital Image Correlation (DIC) technique can record the strain evolution during welding. It is shown that the strain evolution obtained with DIC is in agreement with that found by electrical resistance strain gauges. The results of these experimental measuring methods are compared with numerical results from a FEA of the welding process.

Estimation of Residual Stresses in Steel Welded Joints Using Three Dimensional Finite Element Analysis

2018 ◽  
Author(s):  
Shivdayal Patel ◽  
B. P. Patel ◽  
Suhail Ahmad
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Boundary Conditions ◽  
Welding Speed ◽  
Welded Joints ◽  
Plate Thickness ◽  
Welding Process ◽  
Element Analysis

Welding is one of the most used joining methods in the ship industry. However, residual stresses are induced in the welded joints due to the rapid heating and cooling leading to inhomogenously distributed dimensional changes and non-uniform plastic and thermal strains. A number of factors, such as welding speed, boundary conditions, weld geometry, weld thickness, welding current/voltage, number of weld passes, pre-/post-heating etc, influence the residual stress distribution. The main aim of this work is to estimate the residual stresses in welded joints through finite element analysis and to investigate the effects of boundary conditions, welding speed and plate thickness on through the thickness/surface distributions of residual stresses. The welding process is simulated using 3D Finite element model in ABAQUS FE software in two steps: 1. Transient thermal analysis and 2. Quasi-static thermo-elasto-plastic analysis. The normal residual stresses along and across the weld in the weld tow region are found to be significant with nonlinear distribution. The residual stresses increase with the increase in the thickness of the plates being welded. The nature of the normal residual stress along the weld is found to be tensile-compressive-tensile and the nature of normal residual stress across the weld is found to be tensile along the thickness direction.

scholarly journals Finite Element Prediction of Residual Stress Distributions in a Multipass Welded Piping Branch Junction

2006 ◽  
Author(s):  
Wei Jiang ◽  
Kadda Yahiaoui
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Welding Process ◽  
Pressure Vessels ◽  
Welding Residual Stress ◽  
Stress Distributions ◽  
Multipass Welding ◽  
Hexahedral Elements ◽  
Element Removal

Piping branch junctions and nozzle attachments to main pressure vessels are common engineering components used in the power, oil and gas, and shipbuilding industries amongst others. These components are usually fabricated by multipass welding. The latter process is known to induce residual stresses at the fabrication stage which can have severe adverse effects on the in-service behavior of such critical components. It is thus desirable if the distributions of residual stresses can be predicted well in advance of welding execution. This paper presents a comprehensive study of three dimensional residual stress distributions in a stainless steel tee branch junction during a multipass welding process. A full 3D thermo-mechanical finite element model has been developed for this purpose. A newly developed meshing technique has been used to model the complex intersection areas of the welded junction with all hexahedral elements. Element removal/reactivate technique has been employed to simulate the deposition of filler material. Material, geometry and boundary nonlinearities associated with welding were all taken into account. The analysis results are presented in the form of stress distributions circumferentially along the weldline on both run and branch pipes as well as at the run and branch cross sections. In general, this computational model is capable of predicting 3D through thickness welding residual stress, which can be valuable for structural integrity assessments of complex welded geometries.

Welding Residual Stress of Flange-Plate Steel Reinforced Connections

2012 ◽  
Vol 446-449 ◽  
pp. 3495-3498
Author(s):  
Wei Wang ◽  
Chang Hao Zhang ◽  
Guan Feng Wang ◽  
Juan Zhang
Keyword(s):  
Residual Stresses ◽  
Three Dimensional ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Welding Parameters ◽  
Heat Affect Zone ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Element Analysis ◽  
The Finite Element Analysis

The welding joint method is usually applied in the reinforcing process of the steel moment frame connections. The welding parameters are chosen and discussed and the finite element analysis is employed to analyze the completely penetration joint weld between the flange plates and the column flange. The three-dimensional thermo-structure simulation is conducted. Furthermore, the influence of the residual stresses on the the loading capacity of the reinforced connection is discussed. The temperature field during the welding process and the residual stresses distribution are given. The existence of the welding residual will highly increase the likelihood of brittle fracture of the steel in the heat affect zone.

Residual Stress Measurements in Single and Multi-Pass Groove Weld Specimens Using Neutron Diffraction and the Contour Method

2006 ◽  
Vol 524-525 ◽  
pp. 671-676 ◽  
Author(s):  
M. Kartal ◽  
Mark Turski ◽  
Greg Johnson ◽  
Michael E. Fitzpatrick ◽  
S. Gungor ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Cross Section ◽  
Welding Process ◽  
Contour Method ◽  
Residual Stress Field ◽  
Process Measurements ◽  
Good Agreement

This paper describes the measurement of longitudinal residual stresses within specially designed 200x180x25mm groove weld specimens. The purpose of these measurements was to compare the residual stress field arising from single and multi-pass weld beads laid down within the constraint of a groove in order to validate finite element simulations of the welding process. Measurements were made over the cross section at the mid-bead length, utilising the relatively new Contour method and neutron diffraction. Results from these measurements indicate a larger peak tensile longitudinal residual stresses within the weld region of the multi-pass weld sample. Good agreement is found between both techniques.

Residual Stresses in Strength Mismatched Welded Pipes

2017 ◽  
Author(s):  
Ali Mirzaee-Sisan ◽  
Junkan Wang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Thermal Stresses ◽  
Structural Integrity ◽  
Welding Residual Stress ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Element Analysis ◽  
Girth Welds ◽  
Welded Pipe

It is commonly understood that residual stresses can have significant effects on structural integrity. The extent of such influence varies and is affected by material properties, manufacturing methods and thermal history. Welded components such as pipelines are subject to complex transient temperature fields and associated thermal stresses near the welded regions. These thermal stresses are often high in magnitude and could cause localized yielding around the deposited weld metal. Because of differential thermal expansion/contraction episodes, misfits are introduced into the welded regions which in turn generate residual stresses when the structure has cooled to ambient temperature. This paper is based on a recently completed Joint Industry Project (JIP) led by DNV GL. It briefly reviews published experimental and numerical studies on residual stresses and strength-mismatched girth welds in pipelines. Several Finite Element Analysis (FEA) models of a reeling simulation have been developed including mapping an initial axial residual stress (transverse to the weld) profile onto a seamless girth-welded pipe. The initial welding residual stress distribution used for mapping was measured along the circumference of the girth welds. The predicted residual stresses after reeling simulation was subsequently compared with experimental measurements.

A Study of the Effect of Hardening Model in the Prediction of Welding Residual Stress

2012 ◽  
Author(s):  
Martina M. Joosten ◽  
Martin S. Gallegillo
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Kinematic Hardening ◽  
Welding Process ◽  
Cyclic Hardening ◽  
Welding Residual Stress ◽  
Isotropic Hardening ◽  
Hardening Models ◽  
Set Up

The presence of residual stresses can significantly affect the performance of manufactured products. The welding process is one of the most common causes of large tensile residual stresses, which may contribute to failure by brittle fracture or cause other forms of failure such as damage by corrosion and creep. Welding is a widely used method of fabrication and it can generate high levels of residual stress over significant proportions of the thickness of a component. In order to study the effect of material characterisation on computer based predictions of welding residual stresses, the presented work was carried out as part of the European Network on Neutron Techniques Standardisation for Structural Integrity (NeT). Within the NeT, a task group is investigating a three-pass Tungsten Inert Gas (TIG) weld benchmark. The three-pass specimen offers the possibility of examining the cyclic hardening and annealing behaviour of the weld metal and heat affected zone. A 3D model of the benchmark NeT problem was set up using ABAQUS v6.9.1 and validated against measurements. This paper presents the finite element work. Future papers from the NeT shall present experimental measurements. Different hardening models were considered in order to study their effect on the residual stresses. The different hardening models were isotropic hardening, linear and nonlinear kinematic hardening and combinations of these. Also the effect of annealing on the hardening behaviour is studied. Finally, the results of the simulations are compared to residual stress distributions as given in several standards.

A Study on Numerical Analysis and Residual Stress Evaluation of Welded Joint

2008 ◽  
Vol 575-578 ◽  
pp. 799-804
Author(s):  
Sun Chul Huh
Keyword(s):  
Residual Stress ◽  
Rapid Heating ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Welding Distortion ◽  
Light Weight ◽  
Element Analysis ◽  
Welding Condition ◽  
Heating And Cooling ◽  
Welded Structure

The structures of existing wings had holes for light weight and plates and frames were fixed with rivets or screws, thus, there were difficulties and limits in light weight. Welding process generates distortion and residual stress in the welding due to rapid heating and cooling. Welding distortion and residual in the welded structure result in many troubles such as dimensional inaccuracies in assembling and safety problem during service. The accurate prediction of welding residual stress is thus very important to improve the quality of welding and find the way to reduce itself. In this study, an improvement was made in current joint methods through EB welding and laser welding for light weight of wings and welding strength was measured through strength test. In addition, finite element analysis was performed for welding process so as to induce optimum welding condition.

Evaluation by Two-Dimensional Finite Element Analysis of the Effect of Number of Weld Layers on the Residual Stress Profile in Stainless Steel Pipe Welds

2020 ◽  
Author(s):  
Alexandra K. Zumpetta ◽  
Andrew W. Stockdale ◽  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jessica L. Coughlin
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Weld Bead ◽  
Steel Pipe ◽  
Two Dimensional ◽  
Element Analysis ◽  
Stainless Steel Pipe ◽  
Stress Profiles

Abstract Tensile residual stresses associated with stainless steel pipe welds can promote in-service cracking and influence the need for inspections. Previous research via finite element analysis (FEA) [1] and experimental characterization [2] has shown that welds in thick wall pipe can produce compressive residual stresses at the inner diameter (ID) surface. However, research that has evaluated the relationship between the number of weld layers, stemming from different weld bead sizes, and the resulting pipe residual stress profiles is limited. This investigation used two-dimensional (2D) FEA to evaluate the influence of the number of weld layers (resulting from different weld bead sizes) on the ID surface and through-wall residual stress profiles for varying stainless steel pipe radii, thicknesses, and weld joint geometries. The findings herein are compared to previous experimental results [2]. The results demonstrated that for the larger pipe sizes and the welding conditions investigated, increasing the number of weld layers (reducing individual weld bead sizes) reduced the ID surface tensile axial residual stresses. In the larger pipe sizes, the magnitude of the tensile residual stresses extending through (into) the pipe wall is also reduced with an increased number of weld layers. The FEA results show that the weld joint geometry may not affect the residual stress profiles as strongly as do the number of weld layers, based on the similarities in the tensile stress values for the joint geometries that were evaluated.

Numerical Investigation on Heat Transfer and Residual Stress in a Butt Welded Plate

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
D. Kumaresan ◽  
A. K. Asraff ◽  
R. Muthukumar
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Thermal History ◽  
Plastic Material ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Source Distribution ◽  
Geometrical Shape ◽  
Element Analysis ◽  
Alloy Plate

It is a well known fact that during welding, the metal at the welding zone gets melted and then solidifies, which results in shrinkage in all directions. Residual strain and stress distributions coming from shrinking are largely influenced by the nature and configuration of the welding process, metallurgical characteristics of weld, and the geometrical shape of the weld joint. The residual stress mainly depends on the thermal history cycle through which the specimen undergoes in the welding process. So these thermal history cycles are to be known in order to get a better knowledge of the welding phenomenon and to minimize the risk of failures. In this work, a detailed analysis has been carried out for predicting the heat flow pattern and stress distribution in an aluminum alloy plate during welding. In this study, the modified double ellipsoidal heat source distribution pattern is modeled and considered for the weld pool design. Elastic-plastic material properties at various temperatures are also considered for simulation. A detailed finite element analysis is carried out to predict the welding residual stress. In this, thermal analysis is carried out for actual variable welding speed and these transient thermal histories at various locations were numerically predicted and compared with experimental results. Further, these thermal results are used to predict the residual stress on the weld plate using finite element method.

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