Mitigation of Welding-Induced Tensile Residual Stress at Surface of Heavy Section Plate by In-Process Control Welding With Trailing Heat Sink

2013 ◽  
Author(s):  
Shigetaka Okano ◽  
Masahito Mochizuki
Keyword(s):  
Residual Stress ◽  
Process Control ◽  
Heat Sink ◽  
Stress Measurement ◽  
Tensile Residual Stress ◽  
Low Carbon ◽  
Element Analysis ◽  
Heavy Section ◽  
Weld Residual Stress ◽  
Simulation Results

In this study, in-process control welding with a trailing heat sink was applied to mitigate the weld tensile residual stress at the surface of a heavy section plate of low-carbon austenitic stainless steel. The distribution of the weld residual stress at the surface of the plate was evaluated by X-ray stress measurement and finite element analysis. As the results, it was experimentally and analytically confirmed that the welding-induced tensile residual stress at the welded surface was mitigated by welding with a trailing heat sink. Also, the measurement and simulation results were in good agreement. Based on the simulation results, the mechanisms of mitigation of the residual stress by welding with a trailing heat sink were discussed. It was concluded that the mitigation of the weld residual stress is due to the inverted gradient of temperature from the welded surface to the deepest parts of the plate.

Measurement of Residual Stress in Reactor Nozzle Mock-Ups Containing Dissimilar Metal Welds

2014 ◽  
Author(s):  
Adrian T. DeWald ◽  
Michael R. Hill ◽  
Michael L. Benson ◽  
David L. Rudland
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Tensile Residual Stress ◽  
Contour Method ◽  
Two Dimensional ◽  
Weld Residual Stress ◽  
Accelerate Growth ◽  
Primary Water ◽  
Spatially Varying

Weld residual stresses can significantly impact the performance of structural components. Tensile residual stresses are of particular concern due to their ability to accelerate failure. For example, the presence of tensile residual stress can cause initiation and accelerate growth of primary water stress corrosion cracking (PWSCC). The contour method is a residual stress measurement technique capable of generating two dimensional maps of residual stress, which is particularly useful when applied to welds since they typically contain spatially varying residual stress distributions. The two-dimensional capability of the contour method enables detailed visualization of complex weld residual stress fields. This data can be used to identify locations and magnitude of tensile residual stress hot-spots. This paper provides a summary of the contour method and presents detailed results of contour method measurements made on a mock-up from the NRC/EPRI weld residual stress (WRS) program [1].

Influence of Laser Shock Processing on the Weld Line and Finite Element Simulation

2011 ◽  
Vol 464 ◽  
pp. 627-631
Author(s):  
Jie Zhang ◽  
Ai Hua Sun ◽  
Le Zhu ◽  
Xiang Gu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Residual Stress ◽  
Laser Shock ◽  
Analysis Software ◽  
Laser Shock Processing ◽  
Element Analysis ◽  
Welding Line ◽  
Simulation Results ◽  
Shock Processing

Welding residual stress is one of the main factors that affect the strength and life of components. In order to explore the effect on residual stress of welding line by laser shock processing, finite element analysis software ANSYS is used to simulate the welding process, to calculate the distribution of welding residual stress field. On this basis, then AYSYS/LS-DYNA is used to simulate the laser shock processing on welding line. Simulation results show that residual stress distributions of weld region, heat-affected region and matrix by laser shock processing are clearly improved, and the tensile stress of weld region effectively reduce or eliminate. The simulation results and experimental results are generally consistent, it offer reasons for parameter optimization of welding and laser shock processing by finite element analysis software.

Deep Hole Drill Residual Stress Measurement Technique Experimental Validation

2006 ◽  
Vol 524-525 ◽  
pp. 549-554 ◽  
Author(s):  
W.R. Mabe ◽  
W.J. Koller ◽  
A.M. Holloway ◽  
P.R. Stukenborg
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Test Specimen ◽  
Experimental Validation ◽  
Stress Measurement ◽  
Reference Solution ◽  
Deep Hole ◽  
Element Analysis ◽  
Validation Test

This paper presents the results of an experimental validation of the deep hole drill residual stress measurement method. A validation test specimen was fabricated and plastically loaded to impose a permanent residual stress field within the specimen. The validation test specimen was designed to provide a variety of stress profiles as a function of location within the specimen. A finite element analysis of the validation test specimen was performed in order to provide a reference solution for comparison to the deep hole drill experimental results. Results from experimental testing of the validation test specimen agree well with the finite element analysis reference solution, thereby providing further validation of the deep hole drill method to measure residual stresses.

UK Research Programme on Residual Stresses: Progress to Date

2007 ◽  
Author(s):  
S. K. Bate ◽  
A. P. Warren ◽  
C. T. Watson ◽  
P. Hurrell ◽  
J. A. Francis
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Research Programme ◽  
Assessment Procedure ◽  
Engineering Structures ◽  
Element Analysis ◽  
Simplifying Assumptions ◽  
Modelling Techniques

A long-term UK research programme on residual stresses was launched in 2004. It involves Rolls-Royce plc and Serco Assurance, and is supported by UK industry and academia. The programme is aimed at progressing the understanding of weld residual stresses and the implementation of finite element simulation and residual stress measurement for assessing the integrity of engineering structures. Following on from this, the intention is then to develop improved guidance on residual stress modelling techniques. In the first two years finite element activities have addressed heat source representation, simplified modelling (e.g. 2D v 3D, bead lumping), material hardening models, high temperature behaviour and phase transformations. It is recognized that simplifying assumptions have to be made in order to reduce the computational run-time and modelling complexity, especially for multi-pass welds. The effects of these assumptions on the determined stresses have been considered by carrying out finite element analyses of welded mock-ups. The welded mock-ups have been developed to provide measured residual stress data which are necessary to validate the modelling techniques that have been developed. These activities have been used to support the development of guidelines on the use finite element analysis to predict residual stresses in welded components. These guidelines will be incorporated in the next issue of the British Energy R6 defect assessment procedure.

Relationship Between Forced Vibration Method and Residual Stress in Die Materials

2020 ◽  
Vol 14 (5) ◽  
pp. 824-834
Author(s):  
Masashi Kurose ◽  
Hiromasa Anahara ◽  
Takeshi Tane ◽  
Yoshihide Kuwabara ◽  
Kenta Aoshima ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stress Reduction ◽  
Forced Vibration ◽  
Stress Measurement ◽  
Die Casting ◽  
Tensile Residual Stress ◽  
Cavity Surface ◽  
Repeated Heating ◽  
Die Materials

During aluminum die-casting, tensile residual stress accumulates on the cavity surface of the die by repeated heating and cooling processes. Recently, to improve productivity, dies with high cycle and longer life have become necessary, and reduction or removal of tensile residual stress can be used to prevent heat cracks that cause mold fracture. Heat treatment is often used for residual stress reduction but a more efficient residual stress reduction method that can be carried out with simpler equipment is required. In this study, the relationship between the residual stress after forced vibration and the amplitude at the time of excitation is investigated by mechanical vibration of the SKD61 die materials and the die-casting mold through the application of forced vibration by an eccentric motor. Residual stress on the surface of each test plate treated by the heat treatment and the surface of mold cavity after excitation is evaluated by the X-ray residual stress measurement. It was found that the residual strain after excitation accumulated in compression as the amplitude of oscillation of the specimen became negative. Residual stress in the excitation direction of the specimens increased in the compression direction due to the excitation, demonstrating the effective stress reduction by the excitation method.

A Study on Weld Residual Stress Relaxation by Local Post Weld Heat Treatment for Circumferential Weld

2014 ◽  
Author(s):  
Seung-gun Lee ◽  
Youngho Son
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Nuclear Power ◽  
Post Weld Heat Treatment ◽  
Element Analysis ◽  
Minimum Width ◽  
Weld Residual Stress ◽  
The Status ◽  
Baseline Information ◽  
Weld Heat

Weld residual stress is a troublesome problem in nuclear power plant, because it can accelerate crack growth in weld region. For low alloy steel, Post Weld Heat Treatment (PWHT) is essentially needed to relieve residual stress and to temper the hard regions in the heat affected zone (HAZ). Local PWHT is used when it is impractical to heat the whole component in a furnace. The rules and practices of related codes and standards, such as ASME and AWS, associated with local PWHT are quite different. For example, according to ASME Section III, the minimum width of heated band at each side of the weld shall be the thickness of the weld or 2 in., whichever is less. While, according to ASME B31.1, the width of heated band shall be at least three times the wall thickness at the weld of the thickest part being joined. In this paper, the status of the related code and standard associated with local PWHT is briefly summarized, and baseline information on local PWHT is explained based on FEA (Finite Element Analysis) results and optimized local PWHT parameter is suggested to support current code of practices.

Study on Weld Residual Stress and Crack Propagation Evaluations for a Saddle-Shaped Weld Joint

2013 ◽  
Author(s):  
Jinya Katsuyama ◽  
Koichi Masaki ◽  
Kunio Onizawa
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Weld Joint ◽  
Power Plants ◽  
Structural Integrity ◽  
Piping System ◽  
Stress Distributions ◽  
Analysis Model ◽  
Element Analysis ◽  
Weld Residual Stress

Stress corrosion cracking (SCC) have been observed in reactor coolant pressure boundary piping system at nuclear power plants. When an SCC is found, the structural integrity of piping should be assessed according to a fitness-for-service rule. However, the rule stipulates the assessment procedures for crack growth and failure only for a simple structure such as cylindrical or plate-wise structure. At the present, the methodology even of an SCC growth evaluation for a geometrically complicated piping such as saddle-shaped weld joints has not been established yet. This may be because analyses on the weld residual stress distribution which affects the SCC growth behavior around such portion are difficult to conduct. In this study, we established a finite element analysis model for a saddle-shaped weld joint of pipes. The residual stress distributions produced by the tungsten inert gas (TIG) welding were calculated based on thermal-elastic-plastic analysis with moving and simultaneous heat source models. Analysis results showed complicated weld residual stress distributions, i.e., residual stresses in both hoop and radial directions were tensile at the inner surface near the nozzle corner in branching pipe. SCC growth simulation based on S-version finite element method (S-FEM) using the weld residual stress distributions in saddle-shaped weld joint was also performed. We confirmed an applicability and the accuracy of S-FEM to saddle-shaped weld joint.

Analysis on the Residual Stresses in Functionally Gradient Fe360/Glass-Ceramic Coatings

2013 ◽  
Vol 717 ◽  
pp. 215-220
Author(s):  
Li Ming Zhou ◽  
Wei Gong ◽  
En Ze Wang
Keyword(s):  
Residual Stress ◽  
Glass Ceramic ◽  
Volume Fraction ◽  
Geometric Model ◽  
Low Carbon Steel ◽  
Ceramic Coatings ◽  
Low Carbon ◽  
Element Analysis ◽  
Functionally Gradient ◽  
Gradient Coatings

A novel functionally gradient composite was reported in this article. The composite material are composed of plain low carbon steel Fe360 as a substrate and glass-ceramics containing ZrO2 reinforcing particles as a coating. Based on a mathematical model of the residual stress, the geometric model and finite element analysis models of the Fe360/glass-ceramic gradient coatings were established. The residual stress of the gradient layers was calculated with the commercial software ANSYS 10.0. The results showed that the differences of thermal expansion coefficient and shrinkage rate in each layer resulting from the difference of the volume fraction of ZrO2 in each gradient layer could make the surface layer generate suitable compressive stress. The maximum residual stress presents itself at the interface between the substrate and the gradient coatings. The layer numbers and the thickness of graded coatings have a significant effect on the residual stress.

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