scholarly journals Residual Stress Measurement in a Stainless Steel Clad Ferritic Plate Using the Contour Method

2013 ◽  
Author(s):  
Nida Naveed ◽  
Foroogh Hosseinzadeh ◽  
Jan Kowal
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Stress Measurement ◽  
Base Material ◽  
Pressure Vessels ◽  
Contour Method ◽  
Steel Weld ◽  
Integrity Assessment ◽  
Stainless Steel Weld

In pressure vessels stainless steel weld-overlay cladding is a widely used technique to provide a protective barrier between the corrosive environment and the ferritic low alloy base metal. While the cladding layers enhance corrosion resistance, the induced residual stresses due to the deposition of weld layers are of major concern. It is of paramount importance to understand how residual stresses interact with service loading when the vessel is pressurized. Therefore, knowledge of the initial residual stresses due to cladding is an essential input for structural integrity assessment of pressure vessels. In the present paper the Contour Method was conducted to measure residual stresses in an austenitic steel cladded plate that was fabricated from a ferritic steel base plate with three layers of austenitic stainless steel weld metal cladding deposited on the top surface. The Contour Method was chosen for various reasons. First, it provides a full 2D variation of residual stresses over the plane of interest. Second, it is not limited by the thickness of components or microstructural variations and finally it should potentially capture the variation of residual stresses in each individual weld beads and due to the possible phase transformation in the ferritic base material. The map of longitudinal residual stresses was measured by sectioning the test component along a transverse plane at mid-length. The measured residual stresses were in good agreement with published results in the open literature.

Slitting and Contour Method Residual Stress Measurements in an Edge Welded Beam

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Foroogh Hosseinzadeh ◽  
Muhammed Burak Toparli ◽  
Peter John Bouchard
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Stress Measurement ◽  
Welding Process ◽  
Pressure Vessels ◽  
Contour Method ◽  
Residual Stress Field ◽  
Integrity Assessment ◽  
Stress Measurements

Welding is known to introduce complex three-dimensional residual stresses of substantial magnitude into pressure vessels and pipe-work. For safety-critical components, where welded joints are not stress-relieved, it can be of vital importance to quantify the residual stress field with high certainty in order to perform a reliable structural integrity assessment. Finite element modeling approaches are being increasingly employed by engineers to predict welding residual stresses. However, such predictions are challenging owing to the innate complexity of the welding process (Hurrell et al., Development of Weld Modelling Guidelines in the UK, Proceedings of the ASME Pressure Vessels and Piping Conference, Prague, Czech Republic, July 26–30, 2009, pp. 481–489). The idea of creating weld residual stress benchmarks against which the performance of weld modeling procedures and practitioners can be evaluated is gaining increasing acceptance. A stainless steel beam 50 mm deep by 10 mm wide, autogenously welded along the 10 mm edge, is a candidate residual stress simulation benchmark specimen that has been studied analytically and for which neutron and synchrotron diffraction residual stress measurements are available. The current research was initiated to provide additional experimental residual stress data for the edge-welded beam by applying, in tandem, the slitting and contour residual stress measurement methods. The contour and slitting results were found to be in excellent agreement with each other and correlated closely with published neutron and synchrotron residual stress measurements when differences in gauge volume and shape were accounted for.

Slitting and Contour Method Residual Stress Measurements in an Edge Welded Beam

2010 ◽  
Author(s):  
Foroogh Hosseinzadeh ◽  
P. John Bouchard ◽  
M. Burak Toparli
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Stress Measurement ◽  
Welding Process ◽  
Pressure Vessels ◽  
Contour Method ◽  
Residual Stress Field ◽  
Integrity Assessment ◽  
Stress Measurements

Welding is known to introduce complex three-dimensional residual stresses of substantial magnitude into pressure vessels and pipe-work. For safety-critical components, where welded joints are not stress-relieved, it can be of vital importance to quantify the residual stress field with high certainty in order to perform a reliable structural integrity assessment. Finite element modeling approaches are being increasingly employed by engineers to predict welding residual stresses. However, such predictions are challenging owing to the innate complexity of the welding process [1]. The idea of creating weld residual stress benchmarks against which the performance of weld modeling procedures and practitioners can be evaluated is gaining increasing acceptance. A stainless steel beam 50 mm deep by 10 mm wide, autogenously welded along the 10 mm edge, is a candidate residual stress simulation benchmark specimen that has been studied analytically and for which neutron and synchrotron diffraction residual stress measurements are available. The current research was initiated to provide additional experimental residual stress data for the edge-welded beam by applying, in tandem, the slitting and contour residual stress measurement methods. The contour and slitting results were found to be in excellent agreement with each other and correlated closely with published neutron and synchrotron residual stress measurements when differences in gauge volume and shape were accounted for.

scholarly journals Should Residual Stresses Be Taken Into Account in Structural Integrity Assessment of Offshore Monopiles?

2018 ◽  
Author(s):  
Anais Jacob ◽  
Jeferson Araujo de Oliveira ◽  
Ali Mehmanparast ◽  
Foroogh Hosseinzadeh ◽  
Filippo Berto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Stress Measurement ◽  
Corrosion Cracking ◽  
Residual Stress Measurement ◽  
Offshore Wind ◽  
Contour Method ◽  
Assessment Procedure ◽  
Integrity Assessment

A key challenge in the Offshore Wind industry is assuring the life-cycle structural integrity of wind turbine foundation monopiles. This is due to harsh environmental aspects as well as the loading regime (i.e. constant exposure to wave and wind forces introducing both fatigue and corrosion damage). Welding is a widely used joining technique for the manufacturing of offshore monopile structures. However, this is an aggressive process that introduces high levels of residual stress, which in turn may lead to reduced fatigue life, corrosion cracking resistance and accelerated degradation mechanisms. This study presents evidence that a measurement-informed strategy could be used towards developing a more reliable structural integrity assessment procedure for offshore monopile structures by taking into account the effect of residual stresses. A welded mock-up, 90 mm thick, 2600 mm wide and 800 mm long plate, was fabricated using a typical double-V welding procedure following current industrial practice. The contour method of residual stress measurement was employed to map residual stresses in the welded mock-up as well as in the CT specimens extracted from the weld region of the plate for future fatigue tests. Residual stress measurement results show that the mock-up plate contained tensile residual stresses above yield in the core of the weld, while the extracted CT specimens had lower though still significant residual stress levels. These results indicate that if the initial residual stresses are not carefully considered during fatigue or corrosion cracking tests, the results from the CT specimens alone will likely result in misleading structural life estimations.

scholarly journals Stainless steel weld metal designed to mitigate residual stresses

2009 ◽  
Vol 14 (6) ◽  
pp. 559-565 ◽  
Author(s):  
A. A. Shirzadi ◽  
H. K. D. H. Bhadeshia ◽  
L. Karlsson ◽  
P. J. Withers
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Weld Metal ◽  
Steel Weld ◽  
Stainless Steel Weld ◽  
Steel Weld Metal ◽  
Stainless Steel Weld Metal

scholarly journals Development of Residual Stress Simulation and Experimental Measurement Tools for Stainless Steel Pressure Vessels

2015 ◽  
Author(s):  
Thomas B. Reynolds ◽  
Arthur A. Brown ◽  
Lauren L. Beghini ◽  
Timothy D. Kostka ◽  
Chris W. San Marchi
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Pressure Vessels ◽  
Contour Method ◽  
Residual Stress State ◽  
Measurement Tools ◽  
Fatigue And Fracture ◽  
Evolution Of Microstructure ◽  
Stress Simulation

In forged, welded, and machined components, residual stresses can form during the fabrication process. These residual stresses can significantly alter the fatigue and fracture properties compared to an equivalent component containing no residual stress. When performing lifetime assessment, the residual stress state must be incorporated into the analysis to most accurately reflect the initial condition of the component. The focus of this work is to present the computational and experimental tools that we are developing to predict and measure the residual stresses in stainless steel for use in pressure vessels. The contour method was used to measure the residual stress in stainless steel forgings. These results are compared to the residual stresses predicted using coupled thermo-mechanical simulations that track the evolution of microstructure, strength and residual stress during processing.

Simulation and Measurement of Through–Wall Residual Stresses in a Structural Weld Overlaid Pressurizer Nozzle

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Stephen Marlette ◽  
Paula Freyer ◽  
Michael Smith ◽  
Andrew Goodfellow ◽  
Xavier Pitoiset ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Hole Drilling ◽  
Steel Weld ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Dissimilar Metal ◽  
Stainless Steel Weld ◽  
Stress Profiles

Full structural weld overlays (FSWOLs) have been used extensively as a repair/mitigation technique for primary water stress corrosion cracking in pressurizer nozzle dissimilar metal (DM) welds. To support an approved FSWOL design and safety submission for British Energy pressurized water reactor (PWR) nozzles, an in-depth evaluation was performed to assess the effects of a FSWOL on the through wall residual stress distribution in safety/relief pressurizer nozzles. Two safety/relief pressurizer nozzle mockups were fabricated based on British Energy’s PWR nozzle design. One mockup included the nozzle to safe-end DM weld and the safe-end to stainless steel weld, while the second mockup included the DM weld, the stainless steel weld, and a Westinghouse designed structural weld overlay. The mockups were fabricated utilizing materials and techniques that represented the plant specific nozzles as closely as possible and detailed welding parameters were recorded during fabrication. All welds were subsequently nondestructively evaluated (NDE). A thorough review of the detailed fabrication records and the NDE results was performed and several circumferential positions were selected on each mockup for subsequent residual stress measurement. The through wall residual stress profiles were experimentally measured through the DM weld centerline at the selected circumferential positions using both the deep-hole drilling (DHD) and incremental deep-hole drilling (iDHD) measurement techniques. In addition to experimental residual stress measurements, the through-wall residual stress profiles were simulated using a 2D axisymmetric ansys™ finite element (FE) model. The model utilized the application of temperature constraints on the weld elements to simulate the thermal welding cycle which greatly simplified the simulation as compared with detailed heat source modeling methods. Kinematic strain hardening was used for material modeling of the weld and base metals. A range of residual weld stress profiles was calculated by varying the time at which the temperature constraints were applied to the model. The simulation results were compared with the measurement results. It was found that the effects of the FSWOL were principally threefold. Specifically, the FSWOL causes a much deeper compressive stress field, i.e., the overlay shifts tension out toward the outside diameter (OD) surface. Furthermore, the FSWOL reduces tension in the underlying dissimilar metal weld, and finally, the FSWOL causes higher peak compressive and tensile residual stresses, both of which move deeper into the nozzle wall after the overlay is applied. Relatively good agreement was observed between the FE results and the measurements results.

Study of the Fracture Toughness in Electron Beam Welds

2019 ◽  
Author(s):  
Mehdi Mokhtarishirazabad ◽  
Chris Simpson ◽  
Graeme Horne ◽  
Saurabh Kabra ◽  
Chris Truman ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Electron Beam ◽  
Residual Stresses ◽  
Power Plants ◽  
Structural Integrity ◽  
Electron Beam Welding ◽  
High Energy ◽  
Contour Method ◽  
Process Time ◽  
Integrity Assessment

Abstract High energy welding technologies, such as electron beam, have a number of potential benefits including: faster process time, smaller heat affected zone and potentially favourable weld residual stresses. Therefore, they are good candidates for manufacturing complex components for the next generation of nuclear power plants. However, before electron beam can be deployed on a wide scale, further work is required in a number of areas, including how these welds are treated in structural integrity assessments. As an example, the full extent of the effects of complex residual stress (RS) fields, arising from high energy welding technology, on the fracture behaviour of components has not been fully investigated. This understanding is essential for defect tolerance calculations using integrity assessment procedures. In this study, the fracture toughness of austenitic stainless steel 316L plates with various thicknesses (6mm to 25mm), joined by electron beam welding, is evaluated. Residual stresses were measured using non-destructive diffraction and mechanical relief methods (contour method). This is to examine the effect of welding residual stresses on the resistance of the welded component to fracture.

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