scholarly journals Recent Advances in the Prediction of Weld Residual Stress and Distortion - Part 2

2021 ◽  
Vol 100 (6) ◽  
pp. 193-205
Author(s):  
Yu-Ping Yang ◽  
Keyword(s):  
Residual Stress ◽  
Fatigue Cracks ◽  
Plate Thickness ◽  
Structure Design ◽  
Design Stage ◽  
Distortion Compensation ◽  
Recent Advances ◽  
Weld Residual Stress ◽  
Welding Sequence ◽  
Mitigation Techniques

Weld residual stress can contribute to the reduction of structure lifetime and accelerate the formation of fatigue cracks, brittle fractures, or stress corrosion cracking. Distortion can have a significant impact on the dimensional ac-curacy of assembly, structure strength, and fabrication cost. In the past two decades, there have been many significant and exciting developments in the prediction and mitigation of weld residual stress and distortion. This paper reviews the recent advances in mitigation techniques that have been applied in the structure design, manufacturing, and postweld stages. The techniques used in the structure design stage include selecting the type of weld joint and weld groove, using balanced welding, determining appropriate plate thickness and stiffener spacing, and considering distortion compensation. Mitigation techniques used in the manufacturing stage include welding sequence optimization, reducing welding heating input, selecting low-transformation-temperature filler metals, prebending, precambering, constraints, trailing and stationary cooling, in-processing rolling, transient thermal tensioning, and additional heat sources. Postweld mitigation techniques include postweld heating and mechanical treatment. Finally, the remaining challenges and new development needs were discussed to guide future development in the field of mitigating weld residual stress and distortion.

Effect of Welding Sequence on the Residual Stress Distribution in a Stiffened Plate

2016 ◽  
Author(s):  
Bai-Qiao Chen ◽  
C. Guedes Soares
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Lower Layer ◽  
Plate Thickness ◽  
Three Dimensional ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Steel Plates ◽  
Tension Zone ◽  
Welding Sequence

This work investigates the temperature distribution, deformation and residual stress in steel plates as a result of different sequences of welding. The single-pass gas tungsten arc welding process is simulated by a three dimensional nonlinear thermo-elasto-plastic approach. It is observed that the distribution of residual stress varies through the direction of plate thickness. It is concluded that the welding sequence affects not only the welding deformation but also the residual stress mainly in the lower layer of the plates. An in-depth discussion on the pattern of residual stress distribution is presented, especially on the width of the tension zone. Smaller residual tension zone and slightly lower compressive stress are found in thicker plate.

Numerical Simulation of TIG Welding Distortions: Distortions of a Mock-Up Representative of ITER Vacuum Vessel

2011 ◽  
Author(s):  
Denis Pont ◽  
Mathieu Tisset ◽  
Fre´de´ric Boitout ◽  
Philippe Gilles
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Numerical Simulations ◽  
Nuclear Industry ◽  
Local Fields ◽  
Design Stage ◽  
Strong Impact ◽  
Vacuum Vessel ◽  
Welding Simulation ◽  
Welding Sequence

Welding problems encountered in the nuclear industry have been mainly addressed by weldability tests and the analysis, development of new techniques or improvements through lesson learning. Since a decade, AREVA is developing a complementary approach based on numerical simulation. Residual stresses present in reactors do not constitute a major problem at the design stage; even though they may have a strong impact on some types of damage. Numerical welding simulation in the nuclear industry has focused mainly on residual stress prediction, which constitutes an issue for engineering. PWR components are usually massive; nevertheless distortion may also be a source of concern in component design: some structures are slender in spite of their thickness; narrow gap welding requires a close control of the groove width. AREVA, also working on a fast breeder project, the distortion problem gains in importance. In this prospect, AREVA, world energy expert, paid special attention on the numerical simulation of Gas Tungsten Arc Welding (GTAW) of a mock-up relative to the International Thermonuclear Experimental Reactor (ITER) Vacuum Vessel (VV). One of the challenges of manufacturing the ITER vacuum vessel is the low value of acceptance level of distortion (∼ 10 mm) compared to the global dimensions of the structure (∼ 10 m). Welding simulations of a representative mock-up of VV pattern of the made of austenitic steel plates (316L(N) ITER GRADE) are carried out. The aim of the numerical simulations is to check the quality of the distortion prediction. Multi pass welding simulation reproduces the deposit of each bead by thermo-metallurgical and mechanical calculations. Distortions induced by each weld are computed using a simplified approach (local global method). This method aims at modeling long and numerous welding operations with an acceptable calculation time. Moreover, this method is improved in order to respect welding sequence with partial filling of grooves. After welding sequences, distortions are measured at some representative points of the mock-up. The paper presents the methodology of the numerical simulations and the relevant results: • Residual stress and strain fields in and near the welds (local fields), • Distortion prediction for the global structure. The comparison with experimental distortions shows that the trends of the experimental deformed shape are well represented by the simulations. Moreover, displacement magnitudes are in good agreement with measurements.

scholarly journals Recent Advances in the Prediction of Weld Residual Stress and Distortion - Part 1

2021 ◽  
Vol 100 (5) ◽  
pp. 151-170
Author(s):  
YU-PING YANG ◽  
Keyword(s):  
Residual Stress ◽  
Temperature Response ◽  
Computational Method ◽  
Prediction Methods ◽  
Friction Stir ◽  
Complex Interactions ◽  
Recent Advances ◽  
Weld Residual Stress ◽  
Integrated Computational Materials Engineering ◽  
Computational Materials

Residual stresses and distortions are the result of complex interactions between welding heat input, the material’s high-temperature response, and joint constraint conditions. Both weld residual stress and distortion can significantly impair the performance and reliability of welded structures. In the past two decades, there have been many significant and exciting developments in the prediction and mitigation of weld residual stress and distortion. This paper reviews the recent advances in the prediction of weld residual stress and distortion by focusing on the numerical modeling theory and methods. The prediction methods covered in this paper include a thermo-mechanical-metallurgical method, simplified analysis methods, friction stir welding modeling methods, buckling distortion prediction methods, a welding cloud computational method, integrated manufacturing process modeling, and integrated computational materials engineering (ICME) weld modeling. Remaining challenges and new developments are also discussed to guide future predictions of weld residual stress and distortion.

Development of a Residual Stress Simulation Benchmark for a Single Bead-on-Plate Weldment

2006 ◽  
Author(s):  
Peter J. Bouchard ◽  
Lyndon Edwards ◽  
Anastasius G. Youtsos ◽  
Roger Dennis
Keyword(s):  
Residual Stress ◽  
Assessment Procedure ◽  
Defect Assessment ◽  
Best Estimate ◽  
Weld Residual Stress ◽  
Single Bead ◽  
Stress Prediction ◽  
Stainless Steel Bead ◽  
Stress Simulation ◽  
Network Project

Finite element weld residual stress modelling procedures involve complex non-linear analyses where many assumptions and approximations have to be made by the analyst. Weld modelling guidelines for inclusion in the R6 defect assessment procedure are in preparation and will be accompanied by a series of validation benchmarks that can be used to evaluate the accuracy of weld modelling procedures and assess their suitability for use in fracture assessments. It is intended to base one of the benchmarks on a stainless steel bead-on-plate weldment that has been extensively studied by members of Task Group 1 of the NeT European Network project. This paper uses round robin residual stress measurements from the NeT project to derive a statistically based ‘best estimate’ distribution of transverse stress passing through the wall-section at mid-length of the bead-on-plate weldment. The accuracy of a state-of-the-art residual stress prediction is benchmarked against the best estimate measurements using a root mean square error analysis and comparisons of decomposed components of stress. The appropriateness of using the predicted residual stresses in fracture assessments is assessed by comparing stress intensity factors based on the measured and predicted distributions of stress. The results from these studies will be used to help establish accuracy targets and acceptance criteria for the welding benchmark.

Numerical Simulation for Residual Stress and Deformation of Surface Welding on Membrane Water-Wall

2014 ◽  
Vol 490-491 ◽  
pp. 594-599
Author(s):  
Fan Ling Meng ◽  
Ai Guo Liu
Keyword(s):  
Residual Stress ◽  
Great Influence ◽  
Residual Deformation ◽  
Welding Residual Stress ◽  
Finite Element Software ◽  
Welding Sequence ◽  
Surface Welding ◽  
Stress And Deformation ◽  
Welding Sequences ◽  
Residual Stress And Deformation

Automatic MIG was adopted to weld Inconel 625 alloy on 20 G Membrane Waterwall, which can improve the capacities of high temperature corrosion resistance and wear resistance. To study the influence of Membrane Waterwall surface welding sequences on residual stress and residual deformation, this paper utilized finite element software ABAQUS and segmented moving heat source model to simulate the sequence welding, balanced welding from the middle to sides, balanced welding from sides to the middle, balanced skip welding from middle to sides and balanced skip welding from sides to the middle and studied their residual stresses and deformations. The simulation results indicated that there was a great influence of welding sequences on the residual stress and deformation. The optimal welding sequence was balanced skip welding from middle to sides and balanced skip welding from sides to the middle, which could change the stress distribution, decrease the welding residual stress by 17%, realize the even deformation of the whole welding section and decrease the bending deformation by 50%.

Capability of martensitic low transformation temperature welding consumables for increasing the fatigue strength of high strength steel joints

2020 ◽  
Vol 62 (9) ◽  
pp. 891-900
Author(s):  
Jonas Hensel ◽  
Arne Kromm ◽  
Thomas Nitschke-Pagel ◽  
Jonny Dixneit ◽  
Klaus Dilger
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Fatigue Strength ◽  
High Strength Steel ◽  
Transformation Temperature ◽  
Fatigue Cracks ◽  
High Strength ◽  
Filler Material ◽  
Phase Transformation Temperature ◽  
Filler Materials

Abstract The use of low transformation temperature (LTT) filler materials represents a smart approach for increasing the fatigue strength of welded high strength steel structures apart from the usual procedures of post weld treatment. The main mechanism is based on the effect of the low start temperature of martensite formation on the stress already present during welding. Thus, compressive residual stress formed due to constrained volume expansion in connection with phase transformation become highly effective. Furthermore, the weld metal has a high hardness that can delay the formation of fatigue cracks but also leads to low toughness. Fundamental investigations on the weldability of an LTT filler material are presented in this work, including the characterization of the weld microstructure, its hardness, phase transformation temperature and mechanical properties. Special attention was applied to avoid imperfections in order to ensure a high weld quality for subsequent fatigue testing. Fatigue tests were conducted on the welded joints of the base materials S355J2 and S960QL using conventional filler materials as a comparison to the LTT filler. Butt joints were used with a variation in the weld type (DY-weld and V-weld). In addition, a component-like specimen (longitudinal stiffener) was investigated where the LTT filler material was applied as an additional layer. The joints were characterized with respect to residual stress, its stability during cyclic loading and microstructure. The results show that the application of LTT consumables leads to a significant increase in fatigue strength when basic design guidelines are followed. This enables a benefit from the lightweight design potential of high-strength steel grades.

Two Case Studies in 3-D Residual Stress Prediction for Nuclear Power Applications

2016 ◽  
Author(s):  
Michael L. Benson ◽  
Patrick A. C. Raynaud ◽  
Frederick W. Brust
Keyword(s):  
Residual Stress ◽  
Nuclear Power ◽  
Three Dimensional ◽  
Repair Process ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Weld Residual Stress ◽  
Plant Operations ◽  
Stress Prediction ◽  
Residual Stress Modeling

Residual stress prediction contributes to nuclear safety by enabling engineering estimates of component service lifetimes. Subcritical crack growth mechanisms, in particular, require residual stress assumptions in order to accurately model the degradation phenomena. In many cases encountered in nuclear power plant operations, the component geometry permits two-dimensional (i.e., axisymmetric) modeling. Two recent examples, however, required three-dimensional modeling for a complete understanding of the weld residual stress distribution in the component. This paper describes three-dimensional weld residual stress modeling for two cases: (1) branch connection welds off reactor coolant loop piping and (2) a mockup to demonstrate the effectiveness of the excavate and weld repair process.

Research on the Effects of Welding Sequence on Welding Residual Stress of High-Speed Train Based on SYSWELD

2011 ◽  
Vol 399-401 ◽  
pp. 1806-1811
Author(s):  
Yong Hong Chen ◽  
Peng Chen ◽  
Ai Qin Tian
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Speed ◽  
Element Model ◽  
Welding Residual Stress ◽  
High Speed Train ◽  
Distribution Law ◽  
Element Analysis ◽  
Welding Sequence ◽  
Maximum Residual Stress

The finite element model of the roof of aluminum high-speed train was established, double ellipsoid heat source was employed, and heat elastic-plastic theory was used to simulate welding residual stress of the component under different welding sequence based on the finite element analysis software SYSWELD. The distribution law of welding residual stress was obtained. And the effects of the welding sequence on the value and distribution of residual stress was analyzed. The numerical results showed that the simulation data agree well with experimental test data. The maximum residual stress appears in the weld seam and nearby. The residual stress value decreases far away from the welding center. Welding sequence has a significant impact on the final welding residual stress when welding the roof of aluminum body. The side whose residual stress needs to be controlled should be welded first.

Weld Residual Stress in Large Diameter Nuclear Nozzles

2011 ◽  
Author(s):  
Tao Zhang ◽  
F. W. Brust ◽  
Gery Wilkowski
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Nuclear Power ◽  
Kinematic Hardening ◽  
Large Diameter ◽  
Thick Wall ◽  
Isotropic Hardening ◽  
Residual Stress Field ◽  
Mixed Hardening ◽  
Weld Residual Stress

Weld residual stresses in nuclear power plant can lead to cracking concerns caused by stress corrosion. These are large diameter thick wall pipe and nozzles. Many factors can lead to the development of the weld residual stresses and the distributions of the stress through the wall thickness can vary markedly. Hence, understanding the residual stress distribution is important to evaluate the reliability of pipe and nozzle joints with welds. This paper represents an examination of the weld residual stress distributions which occur in various different size nozzles. The detailed weld residual stress predictions for these nozzles are summarized. Many such weld residual stress solutions have been developed by the authors in the last five years. These distributions will be categorized and organized in this paper and general trends for the causes of the distributions will be established. The residual stress field can therefore feed into a crack growth analysis. The solutions are made using several different constitutive models such as kinematic hardening, isotropic hardening, and mixed hardening model. Necessary fabrication procedures such as repair, overlay and post weld heat treatment are also considered. Some general discussions and comments will conclude the paper.

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