Finite Element Modelling of Reduced Pressure Electron Beam Stainless Steel Plate and Pipe Welds

2012 ◽  
Author(s):  
Benjamin M. E. Pellereau ◽  
Paul R. Hurrell ◽  
Christopher M. Gill ◽  
Kevin Ayres
Keyword(s):  
Finite Element ◽  
Electron Beam ◽  
Welding Process ◽  
Welding Parameters ◽  
Fe Modelling ◽  
Reduced Pressure ◽  
Butt Weld ◽  
Mixed Hardening ◽  
Full Penetration ◽  
Pipe Model

Rolls-Royce plc is conducting work to investigate the feasibility of using Reduced Pressure Electron Beam Welding (RPEB) for thick section welded joints in power plant construction. As part of the work, simple specimens have been manufactured at TWI ltd in order to develop welding parameters and conditions and to examine the achievable weld quality. Previous work in this project has shown good correlations between measured and predicted stresses in RPEB welds in ferritic components [5,6]. This paper describes Finite Element (FE) modelling that was carried out to try to predict the residual stress field generated by the welding process in three of the specimens. The first specimen that was modelled was a full penetration butt weld in 80 mm thick Type 316L plate (W17). The other two models were of circumferential butt welds in 14 inch nominal diameter Type 304L pipe. The first pipe model (W20) was a single pass, 360° weld, while the second (W22) featured a slope-up and slope-down each lasting for 16° either side of a 360° full penetration weld, giving a total weld of 392°. The modelling was carried out in Abaqus [1] using a DFLUX user subroutine to model the welding heat input as a cylindrical heat source, due to the reduced pressure during specimen manufacture, only radiation heat losses were considered. The built-in Chaboche mixed hardening model was used for both materials during the structural analysis. The residual stresses predicted by the FE modelling have been compared with the results of Deep Hole Drilling (DHD) that was carried out on the equivalent specimens. Full details of the measurements are reported in [4].

scholarly journals Development of Welding P92 Pipes Using the Reduced Pressure Electron Beam Welding Process for a Study of Creep Performance

2014 ◽  
Author(s):  
Nick Bagshaw ◽  
Chris Punshon ◽  
John Rothwell
Keyword(s):  
Electron Beam ◽  
Heat Input ◽  
Power Plants ◽  
Electron Beam Welding ◽  
Welding Process ◽  
Welding Parameters ◽  
Pipe Material ◽  
Reduced Pressure ◽  
Type Iv ◽  
Type Iv Cracking

Boiler and steam piping components in power plants are fabricated using creep strength enhanced ferritic (CSEF) steels, which often operate at temperatures above 550°C. Modification of alloy content within these steels has produced better creep performance and higher operating temperatures, which increases the process efficiency of power plants. The improved materials, however, are susceptible to type IV cracking at the welded regions. A better understanding of type IV cracking in these materials is required and is the basis of the Technology Strategy Board (TSB) UK funded VALID (Verified Approaches to Life Management & Improved Design of High Temperature Steels for Advanced Steam Plants) project. In order to study the relationship between creep performance and heat input during welding, several welds with varying amounts of heat input and resultant HAZ widths were produced using the electron beam welding process. The welding parameters were developed with the aid of weld process modeling using the finite element (FE) method, in which the welding parameters were optimized to produce low, medium and high heat input welds. In this paper, the modeling approach and the development of electron beam welds in ASTM A387 grade P92 pipe material are presented. Creep specimens were extracted from the welded pipes and testing is ongoing. The authors acknowledge the VALID project partners, contributors and funding body: Air Liquide, Metrode, Polysoude, E.ON New Build & Technology Ltd, UKE.ON, Doosan, Centrica Energy, SSE, Tenaris, TU Chemnitz, The University of Nottingham, The Open University and UK TSB. Paper published with permission.

Thermomechanical Analysis of the Welding Process Using the Finite Element Method

1975 ◽  
Vol 97 (3) ◽  
pp. 206-213 ◽  
Author(s):  
E. Friedman
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Welding Process ◽  
Thermomechanical Analysis ◽  
Analytical Models ◽  
The Finite Element Method ◽  
Nonuniform Temperature ◽  
Butt Weld ◽  
Transverse Bending ◽  
Finite Element Formulations

Analytical models are developed for calculating temperatures, stresses and distortions resulting from the welding process. The models are implemented in finite element formulations and applied to a longitudinal butt weld. Nonuniform temperature transients are shown to result in the characteristic transverse bending distortions. Residual stresses are greatest in the weld metal and heat-affected zones, while the accumulated plastic strain is maximum at the interface of these two zones on the underside of the weldment.

Finite Element Modelling and Measurements of Residual Stress and Phase Composition in Ferritic Welds

2010 ◽  
Author(s):  
Benjamin M. E. Pellereau ◽  
Christopher M. Gill ◽  
Matthew Dawson ◽  
Paul R. Hurrell ◽  
John Francis ◽  
...  
Keyword(s):  
Finite Element ◽  
Phase Transformation ◽  
Residual Stresses ◽  
Cyclic Hardening ◽  
Tig Welding ◽  
Transformation Model ◽  
Welding Parameters ◽  
Isotropic Hardening ◽  
Low Carbon ◽  
Fe Modelling

This paper describes finite element (FE) modelling and neutron diffraction (ND) measurements to investigate the development of residual stresses in two different geometries of ferritic weld. All specimens were produced using SA508 Grade 3 steel plates, depositing a low carbon SD3 weld filler by mechanised TIG welding. The FE analyses were carried out using Abaqus/VFT and the behaviour of the SA508 steel was modelled using a simplified (Leblond) phase transformation model with isotropic hardening using VFT’s UMAT-WELD subroutine, which includes the change in volume due to phase transformation. Single bead-on-plate specimens were manufactured using a range of mechanised TIG welding parameters. One pass and three pass groove welds were also produced, in order to investigate the cyclic hardening behaviour of the materials, as well as phase transformation effects in a multi-pass weld. FE analyses were then performed to determine how accurately these effects could be modelled. During manufacture, a number of thermocouples were attached to each of the specimens in order to calibrate the heat input to the FE models. The residual stresses in each of the bead on plate welds, as well as the groove weld after the first and the third passes, were then measured using ND at the middle of the plate. The ND measurements for the three pass weld showed no significant cyclic hardening behaviour although some was predicted by the FE analysis. Another key finding of the FE modelling that was seen in all of the models was that the phase transformation acts to reduce the stress levels in the deposited weld metal leaving the largest tensile stresses in a ring at the outer edge of the full heat affected zone (HAZ). There are plans to refine the FE studies using improved material properties when material testing of SA508 and SD3 are completed in the near future.

Measurement and Simulation of Residual Stresses of Electron Beam Welding Joint of Pure Aluminum

2012 ◽  
Vol 184-185 ◽  
pp. 649-652
Author(s):  
Gui Fang Guo ◽  
Shi Qiong Zhou ◽  
Liang Wang ◽  
Li Hao ◽  
Ze Guo Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Electron Beam ◽  
Residual Stresses ◽  
Electron Beam Welding ◽  
Pure Aluminum ◽  
Research Result ◽  
Welding Process ◽  
Hole Drilling ◽  
Longitudinal Residual Stress

The effects of electron beam welding on the residual stresses of welded joints of pure aluminum plate 99.60 are studied by through-hole-drilling and blind-hole-drilling method. Meanwhile, based on the thermal elastic-plastic theory, and making use of ANSYS finite element procedure, a three - dimensional finite element model using mobile heat source of temperature and stresses field of electron beam welding in pure aluminum is established. The welding process is simulated by means of the ANSYS software. The results show that the main residual stress is the longitudinal residual stress, the value of the longitudinal residual stress is much larger than the transverse residual stress. But the residual stress in the thickness is rather small. And in the weld center, the maximum value of residual stresses is lower than its yield strength. The simulation results about the welded residual stresses are almost identical with the experimental results by measuring. So the research result is important to science research and engineering application.

Modeling Residual Stresses in Superduplex Stainless Steel Welded Pipes Using the Finite Element Method

2013 ◽  
Vol 758 ◽  
pp. 1-10
Author(s):  
Fabiano Rezende ◽  
Luís Felipe Guimarães de Souza ◽  
Pedro Manuel Calas Lopes Pacheco
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Welding Process ◽  
Welding Parameters ◽  
Superduplex Stainless Steel ◽  
Mechanical Components ◽  
Element Method

Welding is a complex process where localized and intensive heat is imposed to a piece promoting mechanical and metallurgical changes. Phenomenological aspects of welding process involve couplings among different physical processes and its description is unusually complex. Basically, three couplings are essential: thermal, phase transformation and mechanical phenomena. Welding processes can generate residual stress due to the thermal gradient imposed to the workpiece in association to geometric restrictions. The presence of tensile residual stresses can be especially dangerous to mechanical components submitted to fatigue loadings. The present work regards on study the residual stress in welded superduplex stainless steel pipes using experimental and a numerical analysis. A parametric nonlinear elastoplastic model based on finite element method is used for the evaluation of residual stress in superduplex steel welding. The developed model takes into account the coupling between mechanical and thermal fields and the temperature dependency of the thermomechanical properties. Thermocouples are used to measure the temperature evolution during welding stages. Instrumented hole drilling technique is used for the evaluation of the residual stress after welding process. Experimental data is used to calibrate the numerical model. The methodology is applied to evaluate the behavior of two-pass girth welding (TIG for root pass and SMAW for finishing) in 4 inch diameter seamless tubes of superduplex stainless steel UNS32750. The result shows a good agreement between numerical experimental results. The proposed methodology can be used in complex geometries as a powerful tool to study and adjust welding parameters to minimize the residual stresses on welded mechanical components.

scholarly journals Effect of Electron Beam Welding Parameters on Temperature and Stress Field of AISI P20 Tool Steel in Vacuum Roll-cladding Process

2021 ◽  
Author(s):  
lanyu mao ◽  
Zongan Luo ◽  
Yingying Feng ◽  
Xiaoming Zhang
Keyword(s):  
Electron Beam ◽  
Stress Field ◽  
Tool Steel ◽  
Welding Speed ◽  
Electron Beam Welding ◽  
Welding Process ◽  
Welding Current ◽  
Temperature Fields ◽  
Welding Parameters ◽  
Aisi P20

Abstract Vacuum roll-cladding (VRC) is an effective method to produce high quality ultra-heavy AISI P20 plate steel. In the process of VRC, reasonable welding process of electron beam welding (EBW) can significantly avoid welding cracks and reduce the cost. In this paper, the electron beam welding process of AISI P20 tool steel was simulated by using a combined heat source model based on finite element method, and the temperature field and stress field under different welding parameters were studied respectively . The results showed that welding parameters have a greater effect on weld penetration than that of weld width, which making the aspect ratio increases with the increase of welding current, and decrease with the increase of welding speed. The weld morphologies were consistent with those of the modeling and the measured thermal heat curves were good agreement with those of simulated, which was verified the feasibility and effectiveness of temperature fields. The results of stress fields under different welding parameters indicat ed that lower welding speed and higher welding current resulting in lower residual stress at welded joint, which means lower risk of cracking after EBW. The results of this study have been successfully applied to industrial production.

Computational Optimization of Arc Welding Parameters Using Coupled Genetic Algorithms and Finite Element Method

2013 ◽  
Author(s):  
Mohammad R. Islam ◽  
Jens Rohbrecht ◽  
Arjaan Buijk ◽  
Ehsan Namazi ◽  
Bing Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Genetic Algorithms ◽  
Arc Welding ◽  
Welding Process ◽  
Optimization Method ◽  
Optimization Techniques ◽  
Welding Parameters ◽  
Fe Model ◽  
Optimum Parameters ◽  
Arc Welding Process

An effective and rigorous approach to determine optimum welding process parameters is implementation of advanced computer aided engineering (CAE) tool that integrates efficient optimization techniques and numerical welding simulation. In this paper, an automated computational methodology to determine optimum arc welding process control parameters is proposed. It is a coupled Genetic Algorithms (GA) and Finite Element (FE) based optimization method where GA directly utilizes output responses of FE based welding simulations for iterative optimization. Effectiveness of the method has been demonstrated by predicting optimum parameters of a lap joint specimen of two thin steel plates for minimum distortion. Three dimensional FE model has been developed to simulate the arc welding process and validated by experimental results. Subsequently, it is used by GA as the evaluation model for optimization. The optimization results show that such a CAE based method can predict optimum parameters successfully with limited effort and cost.

scholarly journals NUMERICAL STUDY OF THE TEMPERATURE FIELD FOR Fe3Al LASER WELDING

2021 ◽  
Vol 55 (3) ◽  
Author(s):  
Josef Bradáč ◽  
Jiří Hozman ◽  
Jan Lamač
Keyword(s):  
Temperature Field ◽  
Laser Welding ◽  
Numerical Scheme ◽  
Numerical Study ◽  
Welding Process ◽  
Beam Power ◽  
Welding Parameters ◽  
Original Experiment ◽  
Butt Weld ◽  
Welding Processes

The main objective of this paper was focused on a numerical study related to a proper evaluation of the temperature field during the laser-welding process. The investigated material used for the experiments was Fe3Al, given its properties and promising application potential. The original experiment was based on a 3D model of a butt weld. However, to reduce the computational complexity, a planar variant of the heat-transfer equation with suitable choices of surface and volumetric heat sources, given by modified Gaussian pulses, is used to model the temperature distribution in the fixed cross cut during the laser welding. Subsequently, the numerical scheme based on the discontinuous Galerkin method was employed to evaluate the temperature field more properly and to identify the main characteristics of the molten zone. Finally, the numerical study was performed for various combinations of the welding parameters, such as laser-beam power and welding speed. The obtained results were in good agreement with the expected behavior, and thus illustrate the optimization potential of the proposed numerical scheme in the similar issues of a laser-welding processes.

Experimental validation of a predictive model for numerical simulation of thermo-metallurgical phenomena during electron beam welding

2004 ◽  
Vol 120 ◽  
pp. 599-606
Author(s):  
M. Carin ◽  
Ph. Rogeon ◽  
D. Carron ◽  
Ph. Lemasson ◽  
D. Couedel ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Electron Beam ◽  
Heat Affected Zone ◽  
Experimental Validation ◽  
Electron Beam Welding ◽  
Welding Process ◽  
Experimental Measurements ◽  
Finite Element Code ◽  
Thermal Cycles

In the present work, thermal cycles measured with thermocouples embedded in specimens are employed to validate a numerical thermometallurgical model of an Electron Beam welding process. The implemented instrumentation techniques aim at reducing the perturbations induced by the sensors in place. A comparison between simulations performed on finite element code SYSWELD and the experimental measurements carried out on 16MnNiMo5 steel in the case of a partial penetration is achieved. This comparison is based on thermal cycles and also on microstructural evolutions, shapes of fusion zone (FZ) and heat affected zone (HAZ).

3-D Finite Element Simulation of Welding Residual Stresses in Pipe-Flange Joints: Effect of Welding Parameters

2005 ◽  
Vol 490-491 ◽  
pp. 79-84 ◽  
Author(s):  
M. Siddique ◽  
Muhammad Abid ◽  
H.F. Junejo ◽  
R.A. Mufti
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Three Dimensional ◽  
Welding Current ◽  
Pipe Diameter ◽  
Welding Parameters ◽  
Geometrical Parameters ◽  
Fe Model ◽  
Butt Weld ◽  
Element Simulation

This paper presents results of detailed three-dimensional finite element simulation of residual stress distribution in welded Pipe-Flange Joints with emphasis on the effect of welding parameters and geometrical size of the model. Single-pass Metal Inert Gas welding with single “V” Butt-weld geometry is used in the study. The effect of two basic welding parameters including welding current and speed and two geometrical parameters i.e. pipe diameter and wall-thickness are examined. For both welding current and welding speed, three sets of parameters comprising of low, medium and high values are used. To analyze the effect of each parameter explicitly only one parameter is changed at one time. In most of the cases 100 mm nominal pipe diameter is used. A FE Model for 200 mm nominal pipe diameter is also analyzed to determine the effect of pipe diameter.

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