Residual Stress Assessment for Pressure Vessel Subject to Thermal Shock

2017 ◽  
Author(s):  
Jushin Hsiao ◽  
Haiyang Qian ◽  
Christopher Brunner ◽  
Thomas R. Bober ◽  
Lynn D’Amico ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Pressure Vessels ◽  
Residual Stress Distribution ◽  
Life Assessment ◽  
Systematic Analysis ◽  
Maximum Residual Stress ◽  
Film Coefficient ◽  
Assessment Procedures ◽  
Thermal Shocks

API 579-1/ASME FFS-1 Part 9 provides assessment procedures for evaluating crack-like flaws in components to determine if it is fit for continued service. Although residual stress distribution is required as an input to perform a fatigue life assessment, no procedure or guideline is available for evaluating this crack driving force resulting from thermal shocks. Through a systematic analysis, a conservative residual stress distribution can be obtained for pressure vessels subject to thermal shocks. For the two thick-walled vessels considered, the maximum residual stress occurs when the vessel is half filled with water. The conservative residual stress provides the needed input when using API 579-1/ASME FFS-1 for evaluating crack-like flaws in components. Dependence of the residual stress on film coefficient, temperature difference between water and metal surface, and water level inside the vessel is also presented so that refinement can be made on life assessment when additional field data becomes available.

Residual Stress Measurement on a Narrow Gap Dissimilar Metal Weld Pipe

2009 ◽  
Author(s):  
Xavier Ficquet ◽  
Laurie Chidwick ◽  
Philippe Gilles ◽  
Pierre Joly
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Safety Assessment ◽  
Stress Measurement ◽  
Residual Stress Distribution ◽  
Narrow Gap ◽  
Mapping Procedure ◽  
Assessment Procedures

Prior knowledge of the magnitude and distribution of residual stresses in welded components is essential if a cost effective analyses of the integrity of the components is to be made. AREVA NP has recently developed, for EPR applications, narrow gap welding techniques, for joining ferritic low alloy steel heavy section components to austenitic, stainless steel piping systems, in nuclear reactors. An appraisal of available measurement methods was carried out and two residual stress measurement techniques were used to obtain through-thickness residual stress distributions in a fully circumferential narrow gap welded pipe, the neutron diffraction, which is not presented in this paper and the deep hole drilling (DHD) method. The DHD method was used to obtain the axial and hoop residual stresses along the weld centreline and on the heat affected zone in the ferritic and stainless steel sides up to depths of about 40mm from the outer surface of the pipe. The measured residual stress distribution in the weld centreline is compared with representative residual stress distribution provided in UK safety assessment procedures. It is found that the current safety assessment procedures BS 7910:2005 and R6 are conservative. The DHD measurements were made only at limited points in and adjacent to the circumferential weld. In order to estimate the complete residual stress distribution present in the pipe, a measurement mapping procedure using finite element (FE) analysis was implemented. Therefore this paper also provides the estimates of the full residual stress state present in the pipe based on the mapping procedure.

Investigation of Residual Stresses Caused by Welding, Cladding and Tempering of Reactor Pressure Vessels

2003 ◽  
Author(s):  
V. I. Kostylev ◽  
B. Z. Margolin ◽  
A. Y. Varovin ◽  
E. Keim
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Weld Metal ◽  
Pressure Vessels ◽  
Residual Stress Distribution ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Reactor Pressure

Calculations of residual stress fields, which arise after welding, cladding and tempering, were performed as applied to reactor pressure vessels (RPVs) of WWER types. These calculations are based on a procedure, which takes into account Feα↔Feγ transformation happening in base and weld metal under welding and cladding, and also creep during tempering. The procedure is based on solutions of the temperature and non-isothermal elasto-plastic problem with and without creep by the finite element method. On the basis of the performed investigation it is shown that Feα↔Feγ transformation may affect the residual stress distribution. An analysis of cases has been performed for which the above effect is strong and for which this effect may be ignored. On the basis of the calculation performed, an engineering procedure is proposed that allows to determine the residual stress fields in welds of the WWER-440 and WWER-1000 for various durations of post-weld tempering.

Assessments of Residual Stress Due to Weld-Overlay Cladding and Structural Integrity of Reactor Pressure Vessel

2010 ◽  
Author(s):  
Jinya Katsuyama ◽  
Hiroyuki Nishikawa ◽  
Makoto Udagawa ◽  
Mitsuyuki Nakamura ◽  
Kunio Onizawa
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Stress Distribution ◽  
Structural Integrity ◽  
Base Material ◽  
Pressure Vessels ◽  
Residual Stress Distribution ◽  
Weld Overlay ◽  
Weld Residual Stress ◽  
Reactor Pressure

Austenitic stainless steel is cladded on the inner surface of ferritic low alloy steel of reactor pressure vessels (RPVs) for protecting the vessel walls against the corrosion. After the manufacturing process of the RPVs including weld-overlay cladding and post-weld heat treatments (PWHT), the residual stress still remain in such dissimilar welds. The residual stresses generated within the cladding and base material were measured as-welded and PWHT conditions using the sectioning and deep-hole-drilling (DHD) techniques. Thermal-elastic-plastic-creep analyses considering the phase transformation in heat affected zone using finite element method were also performed to evaluate the weld residual stress produced by weld overlay cladding and PWHT. By comparing analytical results with those measured ones, it was shown that there was a good agreement of residual stress distribution within the cladding and base material. Tensile residual stress in cladding is mostly due to the difference between the thermal expansions of cladding and base materials. It was also shown that taking the phase transformation during welding into account is important to improve the accuracy of weld residual stress analysis. Using the calculated residual stress distribution, fracture mechanics analysis for a postulated flaw during pressurized thermal shock (PTS) events have been performed. The effect of weld residual stress on the structural integrity of RPV was evaluated through some case studies. The result indicates that consideration of weld residual stress produced by weld-overlay cladding and PWHT is important for assessing the structural integrity of RPVs.

Numerical Simulation of Temperature Field and Residual Stress in Multi-Pass Welds in 2.25Cr-1Mo-0.25V Steel Plate and Comparison With Experimental Measurements

2017 ◽  
Author(s):  
Mu Qin ◽  
Guangxu Cheng ◽  
Zaoxiao Zhang ◽  
Qing Li ◽  
Jianxiao Zhang
Keyword(s):  
Residual Stress ◽  
Temperature Distribution ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Pressure Vessels ◽  
Residual Stress Distribution ◽  
Bottom Surface ◽  
Transient Temperature ◽  
Transient Temperature Distribution ◽  
Welding Processes

The 2.25Cr-1Mo-0.25V steels are widely used in the petroleum chemical industry for the manufacturing of pressure vessels. The multi-pass welding is a critical type of fabrication in hydrogenation reactor. However, very complicated residual stresses could be generated during the multi-pass welding process. The presence of residual stresses could have significant influence on the performance of welded product. In the present work, the transient temperature distribution and residual stress distribution in welding of 2.25Cr-1Mo-0.25V steel are analyzed by using numerical method. An uncoupled thermal-mechanical two-dimensional (2-D) FEM is proposed under the ABAQUS environment. The transient temperature distribution and the residual stress distribution during the welding processes are determined through the finite element method. A group of experiments by using the blind-hole method have been conducted to validate the numerical results. The results of 2-D model agree well with the experiment. The result shows that the maximum welding stress generated at heat affected zone (HAZ) both at the top and bottom surface whether to transverse stress or longitudinal stress.

Influence of the Welded Joint on the Mechanical Behavior of Steel Piles during Static and Dynamic Deformation

2007 ◽  
Vol 345-346 ◽  
pp. 1469-1472
Author(s):  
Gab Chul Jang ◽  
Kyong Ho Chang ◽  
Chin Hyung Lee
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Mechanical Behavior ◽  
Welded Joint ◽  
Dynamic Deformation ◽  
Three Dimensional ◽  
Steel Structures ◽  
Residual Stress Distribution ◽  
Dynamic Mechanical Behavior ◽  
Steel Piles

During manufacturing the welded joint of steel structures, residual stress is produced and weld metal is used inevitably. And residual stress and weld metal influence on the static and dynamic mechanical behavior of steel structures. Therefore, to predict the mechanical behavior of steel pile with a welded joint during static and dynamic deformation, the research on the influence of the welded joints on the static and dynamic behavior of steel pile is clarified. In this paper, the residual stress distribution in a welded joint of steel piles was investigated by using three-dimensional welding analysis. The static and dynamic mechanical behavior of steel piles with a welded joint is investigated by three-dimensional elastic-plastic finite element analysis using a proposed dynamic hysteresis model. Numerical analyses of the steel pile with a welded joint were compared to that without a welded joint with respect to load carrying capacity and residual stress distribution. The influence of the welded joint on the mechanical behavior of steel piles during static and dynamic deformation was clarified by comparing analytical results

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