Measurement of Welding Residual Stress in Reactor Components

2011 ◽  
Author(s):  
Adrian T. DeWald ◽  
Michael R. Hill
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
The United States ◽  
Welding Residual Stress ◽  
Contour Method ◽  
Two Dimensional ◽  
Stress Distributions ◽  
Weld Residual Stress ◽  
Metal Weld

Welding residual stresses can significantly impact the performance of structural components. Tensile residual stresses are of particular concern due to their ability to cause significant degradation to the PWSCC resistance of structural materials. 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 due to the complex residual stress distributions that generally result. 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 the dissimilar metal weld region of pressurizer relief nozzles removed from the cancelled WNP-3 plant in the United States as part of the NRC/EPRI weld residual stress (WRS) program [1].

Measurement of Welding Residual Stress in Dissimilar Metal Welds Using the Contour Method

2011 ◽  
Author(s):  
Adrian T. DeWald ◽  
Michael R. Hill ◽  
Eric Willis
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
The United States ◽  
Welding Residual Stress ◽  
Contour Method ◽  
Two Dimensional ◽  
Stress Distributions ◽  
Dissimilar Metal ◽  
Weld Residual Stress

Welding residual stresses can significantly impact the performance of structural components. Tensile residual stresses are of particular concern due to their ability to cause significant degradation to the PWSCC resistance of structural materials. 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 due to the complex residual stress distributions that generally result. 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 the dissimilar metal weld region of pressurizer relief nozzles removed from the cancelled WNP-3 plant in the United States as part of the NRC/EPRI weld residual stress (WRS) program [1].

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].

Experimental Study of the Weld Residual Stress in Manually and Mechanically Fabricated Dissimilar Metal Weld

2018 ◽  
Author(s):  
Xinjian Duan ◽  
Andrew Glover ◽  
Dongmei Sun ◽  
Sanjooram Paddea
Keyword(s):  
Residual Stress ◽  
Experimental Study ◽  
Stress Measurement ◽  
Welding Process ◽  
Contour Method ◽  
Inconel 600 ◽  
Dissimilar Metal ◽  
Weld Residual Stress ◽  
Dissimilar Metal Weld ◽  
Metal Weld

The dissimilar metal welds between the Inconel 600 flow element and the SA-106 Grade B carbon pipe with Alloy 82 or Alloy 182 filler material of some CANDU® designs have been identified as being susceptible to Primary Water Stress Corrosion Cracking (PWSCC). Initiation and growth of PWSCC in a Dissimilar Metal Weld (DMW) are driven primarily by Welding Residual Stresses (WRS). The present paper focuses on the experimental study of weld residual stress distribution in manually and mechanically fabricated DMWs with emphasis on the effect of repair. A series of DMW samples are firstly fabricated in accordance with the original welding procedures for those DMWs in the field, which were fabricated in 1970s and 1980s. Multiple thermocouples were used to record the temperature evolution during the entire welding process. These samples were then examined by ASME qualified personnel in accordance with the requirements for Class 1 weld in Article 9 of Section V of ASME BVPC using Visual Testing (VT) and Radiography Testing (RT). Repair was then performed in some samples, and further NDE examinations were performed. The qualified samples (with and without repair) were finally subject to destructive weld residual stress measurement using contour method. It is observed that weld repair dramatically changes the distribution of weld residuals tress. The use of a constant through-thickness WRS of 60,000 psi (415 MPa) is justified as the bounding case.

scholarly journals Cross-Sectional Mapping of Residual Stresses by Measuring the Surface Contour After a Cut

2000 ◽  
Vol 123 (2) ◽  
pp. 162-168 ◽  
Author(s):  
M. B. Prime
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Superposition Principle ◽  
New Method ◽  
Contour Method ◽  
Stress Profile ◽  
Relaxation Methods ◽  
Cross Sectional ◽  
Residual Stress Profile

A powerful new method for residual stress measurement is presented. A part is cut in two, and the contour, or profile, of the resulting new surface is measured to determine the displacements caused by release of the residual stresses. Analytically, for example using a finite element model, the opposite of the measured contour is applied to the surface as a displacement boundary condition. By Bueckner’s superposition principle, this calculation gives the original residual stresses normal to the plane of the cut. This “contour method” is more powerful than other relaxation methods because it can determine an arbitrary cross-sectional area map of residual stress, yet more simple because the stresses can be determined directly from the data without a tedious inversion technique. The new method is verified with a numerical simulation, then experimentally validated on a steel beam with a known residual stress profile.

On the Mechanics of Residual Stresses in Girth Welds

2006 ◽  
Vol 129 (3) ◽  
pp. 345-354 ◽  
Author(s):  
P. Dong
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Relative Importance ◽  
Stress Distributions ◽  
Unified Framework ◽  
Joint Geometry ◽  
Weld Residual Stress ◽  
Girth Welds ◽  
Welding Procedure

In this paper, some of the important controlling parameters governing weld residual stress distributions are presented for girth welds in pipe and vessel components, based on a large number of residual stress solutions available to date. The focus is placed upon the understanding of some of the overall characteristics in through-wall residual stress distributions and their generalization for vessel and pipe girth welds. In doing so, a unified framework for prescribing residual stress distributions is outlined for fitness-for-service assessment of vessel and pipe girth welds. The effects of various joint geometry and welding procedure parameters on through thickness residual stress distributions are also demonstrated in the order of their relative importance.

scholarly journals Experimental Characterisation and Numerical Modelling of Residual Stresses in a Nuclear Safe-End Dissimilar Metal Weld Joint

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1298
Author(s):  
Shuyan Zhang ◽  
Zhuozhi Fan ◽  
Jun Li ◽  
Shuwen Wen ◽  
Sanjooram Paddea ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Weld Joint ◽  
Steel Tube ◽  
Contour Method ◽  
Fe Modelling ◽  
Dissimilar Metal ◽  
Dissimilar Metal Weld ◽  
Metal Weld

In this study, a mock-up of a nuclear safe-end dissimilar metal weld (DMW) joint (SA508-3/316L) was manufactured. The manufacturing process involved cladding and buttering of the ferritic steel tube (SA508-3). It was then subjected to a stress relief heat treatment before being girth welded together with the stainless steel tube (316L). The finished mock-up was subsequently machined to its final dimension. The weld residual stresses were thoroughly characterised using neutron diffraction and the contour method. A detailed finite element (FE) modelling exercise was also carried out for the prediction of the weld residual stresses resulting from the manufacturing processes of the DMW joint. Both the experimental and numerical results showed high levels of tensile residual stresses predominantly in the hoop direction of the weld joint in its final machined condition, tending towards the OD surface. The maximum hoop residual stress determined by the contour method was 500 MPa, which compared very well with the FE prediction of 467.7 Mpa. Along the neutron scan line at the OD subsurface across the weld joint, both the contour method and the FE modelling gave maximum hoop residual stress near the weld fusion line on the 316L side at 388.2 and 453.2 Mpa respectively, whereas the neutron diffraction measured a similar value of 480.6 Mpa in the buttering zone near the SA508-3 side. The results of this research thus demonstrated the reasonable consistency of the three techniques employed in revealing the level and distribution of the residual stresses in the DMW joint for nuclear applications.

High-Temperature Constitutive Behavior of Austenitic Stainless Steel for Weld Residual Stress Modeling

2012 ◽  
Author(s):  
Dongxiao Qiao ◽  
Wei Zhang ◽  
Zhili Feng
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
High Temperature ◽  
Residual Stresses ◽  
Constitutive Rule ◽  
Dissimilar Metal ◽  
Weld Residual Stress ◽  
Dissimilar Metal Weld ◽  
Metal Weld

Weld residual stress is a major driving force for initiation and growth of primary water stress corrosion cracking (PWSCC), which is a critical challenge for weld integrity of reactor pressure vessel nozzles in nuclear industry. Predicting weld residual stresses for the purpose of understanding and mitigating PWSCC requires the knowledge of material constitutive rule especially strain hardening behavior over a wide range of temperatures. Though it is adequate for describing deformation at low temperature, the conventional, rate-independent, elastic-plastic constitutive rule falls short in predicting the strong microstructure-mechanical interaction such as the softening due to recovery (dislocation annihilation and realignment) and recrystallization at elevated temperature in welding. To quantify the extent of softening under temperature and strain conditions relevant to welding, a framework has been developed by combining advanced experimental techniques and finite element modeling. First, physical simulation in a Gleeble testing machine is used to simulate the temperature transients typical of dissimilar metal weld by subjecting round tensile bar shaped specimens to rapid heating and cooling. Second, the digital image correlation (DIC) technique is used to map the non-uniform strain field and extract local strain history needed for accurately determining the true stress vs. true strain curve of softened material. Third, the thermally-mechanically processed specimens are characterized metallographically to correlate the microstructure changes to the measured stress-strain behavior. Finally, a thermal-stress finite element model of three-bar frame is used to study the effect of softening on the predicted weld residual stresses. As a first step toward developing the much-needed, comprehensive material constitutive relation database for dissimilar metal weld, the framework has been applied to study AISI 304L austenitic stainless steel. The extent of softening due to different duration of high-temperature exposure is studied and its influence on final residual stresses is discussed.

Evaluation of Welding Residual Stresses in Power Plant Facilities by Using a Newly Developed Indentation Technique

2002 ◽  
Author(s):  
Jae-il Jang ◽  
Dongil Son ◽  
Yeol Choi ◽  
Yun-Hee Lee ◽  
Won-Jae Ji ◽  
...  
Keyword(s):  
Residual Stress ◽  
Power Plant ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Welding Residual Stress ◽  
Large Scatter ◽  
Indentation Technique ◽  
Cutting Test ◽  
Non Destructive ◽  
Non Destructive Techniques

It is well known that residual stress is one of the important problems in welding design/fabrications and sound maintenance of welded structures. Thus, the demand for quantitative evaluation of welding residual stress has been increased. However, conventional non-destructive techniques for welding residual stress measurement have many difficulties in in-field applications according to poor repeatability, large scatter of obtained data, complex procedures, inaccurate results, and etc. To overcome these difficulties, a newly developed indentation technique was proposed in this study, and applied to evaluate the welding residual stress in electric power plant facilities. By comparing with the stress values obtained from the destructive saw-cutting test, it could be concluded that the new indentation technique is very useful for quantitative/non-destructive evaluation of welding residual stresses in industrial fields such as power plant facilities.

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