scholarly journals Numerical study for reliability assessment of a corroding pipe to flange weld joint over its lifetime

2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Mourad Nahal ◽  
Abdelaziz Lakehal ◽  
Rabia Khelif
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Weld Joint ◽  
Numerical Study ◽  
Reliability Assessment ◽  
Welding Process ◽  
Stress Effects ◽  
Corrosion Rates ◽  
Welded Connection ◽  
Stress Models

Numerical model of a corroded weld joint connecting pipe to flange using a finite element method was developed, and coupled with usual stress models. The structure material has been characterized experimentally. Monte Carlo simulations, FORM and SORM methods have been applied for estimating reliability and failure probability under corrosion and residual stress effects. A numerical case with various corrosion rates was conducted to determine the reliability of the welded connection pipe to flange. The obtained results show that the heat affected zone is very sensitive to corrosion effects due to the welding process.

The Effect of Strength Mis-Match and Residual Stress in ECA of Girth Welds With Internal Circumferential Cracks

2009 ◽  
Author(s):  
Ali Mirzaee Sisan ◽  
Afshin Motarjemi
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Driving Forces ◽  
Numerical Study ◽  
Welding Process ◽  
Detailed Comparison ◽  
Weld Strength ◽  
Residual Stress Field ◽  
Girth Welds ◽  
Welded Pipe

A numerical study was carried out to quantify the effect of a residual stress field on subsequent fracture behaviour of a girth welded pipe with an internal circumferential long crack when subjected to high applied strain loading. In order to introduce an initial residual stress field similar to a welding process in a pipe, a quenching process was numerically simulated and associated residual stress profiles were modified and mapped into the finite element (FE) models. A detailed comparison between the crack driving force for various cases with and without residual stress and weld strength mismatch was carried out for cases under a high plastic deformation regime. The BS7910 procedure was also used to predict crack driving forces using its current assumption of interaction of residual stress with primary loads. The results obtained from the FE analyses were compared with the BS7910 predictions.

Modeling Residual Stresses in Superduplex Stainless Steel Welded Pipes Using the Finite Element Method

2013 ◽  
Vol 758 ◽  
pp. 1-10
Author(s):  
Fabiano Rezende ◽  
Luís Felipe Guimarães de Souza ◽  
Pedro Manuel Calas Lopes Pacheco
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Welding Process ◽  
Welding Parameters ◽  
Superduplex Stainless Steel ◽  
Mechanical Components ◽  
Element Method

Welding is a complex process where localized and intensive heat is imposed to a piece promoting mechanical and metallurgical changes. Phenomenological aspects of welding process involve couplings among different physical processes and its description is unusually complex. Basically, three couplings are essential: thermal, phase transformation and mechanical phenomena. Welding processes can generate residual stress due to the thermal gradient imposed to the workpiece in association to geometric restrictions. The presence of tensile residual stresses can be especially dangerous to mechanical components submitted to fatigue loadings. The present work regards on study the residual stress in welded superduplex stainless steel pipes using experimental and a numerical analysis. A parametric nonlinear elastoplastic model based on finite element method is used for the evaluation of residual stress in superduplex steel welding. The developed model takes into account the coupling between mechanical and thermal fields and the temperature dependency of the thermomechanical properties. Thermocouples are used to measure the temperature evolution during welding stages. Instrumented hole drilling technique is used for the evaluation of the residual stress after welding process. Experimental data is used to calibrate the numerical model. The methodology is applied to evaluate the behavior of two-pass girth welding (TIG for root pass and SMAW for finishing) in 4 inch diameter seamless tubes of superduplex stainless steel UNS32750. The result shows a good agreement between numerical experimental results. The proposed methodology can be used in complex geometries as a powerful tool to study and adjust welding parameters to minimize the residual stresses on welded mechanical components.

Residual Stresses in Butt Welding of Two Circular Pipes: An Experimental and Numerical Investigation

2014 ◽  
Author(s):  
Gurinder Singh Brar
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Welding Process ◽  
Diffraction Method ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray

Welding is a reliable and efficient joining process in which the coalescence of metals is achieved by fusion. Welding is carried out with a very complex thermal cycle which results in irreversible elastic-plastic deformation and residual stresses in and around fusion zone and heat affected zone (HAZ). A residual stress due to welding arises from the differential heating of the plates due to the weld heat source. Residual stresses may be an advantage or disadvantage in structural components depending on their nature and magnitude. The beneficial effect of these compressive stresses have been widely used in industry as these are believed to increase fatigue strength of the component and reduce stress corrosion cracking and brittle fracture. But due to the presence of residual stresses in and around the weld zone the strength and life of the component is also reduced. To understand the behavior of residual stresses, two 10 mm thick Fe410WC mild steel plates are butt welded using the Metal Active Gas (MAG) process. An experimental method (X-ray diffraction) and numerical analysis (finite element analysis) were then carried out to calculate the residual stress values in the welded plates. Three types of V-butt weld joint — two-pass, three-pass and four-pass were considered in this study. In multi-pass welding operation the residual stress pattern developed in the material changes with each weld pass. In X-ray diffraction method, the residual stresses were derived from the elastic strain measurements using a Young’s modulus value of 210 GPa and Poisson’s ratio of 0.3. Finite element method based, SolidWorks software was used to develop coupled thermal-mechanical three dimension finite element model. The finite element model was evaluated for the transient temperatures and residual stresses during welding. Also variations of the physical and mechanical properties of material with the temperature were taken into account. The numerical results for peak transverse residual stresses attained in the welded plates for two-pass, three-pass and four-pass welded joint were 67.7 N/mm2, 58.6 N/mm2, and 48.1 N/mm2 respectively. The peak temperature attained during welding process comes out to be 970°C for two-pass weld, 820.8°C for three-pass weld and 651.9°C for four-pass weld. It can be concluded that due to increase in the number of passes during welding process or deposition weld beads, the residual stresses and temperature distribution decrease. Also, the results obtained by finite element method agree well with those from experimental X-ray diffraction method.

A Numerical Study on Mock-Up Downsizing to Predict Residual Stresses at CRDM Welds

2010 ◽  
Author(s):  
Ik-Joong Kim ◽  
Jae-Uk Jeong ◽  
Jae-Boong Choi ◽  
Young-Jin Kim ◽  
Sung-Woo Kim ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Nuclear Power ◽  
Power Plants ◽  
Numerical Study ◽  
Welding Process ◽  
Piping System ◽  
Experimental Conditions ◽  
Control Rod ◽  
Set Up

Since several defects caused by PWSCC (Primary Water Stress Corrosion Cracking) have been observed at the piping system of nuclear power plants, during the last two decades, lots of analytical and experimental researches have been performed to find out the relationship between the residual stress and PWSCC initiations. The present research deals with prediction of the residual stress at welding parts of CRDM (Control Rod Drive Mechanism). Especially, numerical investigations are carried out to support relevant experimental set-up because it is not easy to prepare large-sized mock-ups comparable to real geometry. First, preliminary examination was performed to establish an optimized welding process simulation procedure to accurately predict weld residual stresses. Then, detailed parametric FE analyses were carried out to examine effects of varying geometries and experimental conditions. Key findings were obtained from the FE analyses, which were used for finalizing the configuration of mock-up, are fully discussed in this manuscript.

scholarly journals Numerical study on the effect of welding and heating treatments on strength of high strength steel column

2018 ◽  
Author(s):  
Jiang Jin ◽  
Wei Bao ◽  
J. Liu ◽  
Z.Y. Peng
Keyword(s):  
Residual Stress ◽  
High Strength Steel ◽  
Arc Welding ◽  
Numerical Study ◽  
Welding Process ◽  
High Strength ◽  
Residual Stress Field ◽  
Heating Treatment ◽  
Welding Processes ◽  
Box Columns

High strength steel box columns are usually fabricated from steel slab by applying welding. The welding process can introduce residual stresses and geometric imperfections into the columns and influence the column strength. In this study, a numerical investigation on the behavior of high strength steel thin-walled box columns under the compression force was carried out. The welding processes were firstly simulated with commercial package ABAQUS in this study to find out the residual stress distributions in high strength steel box column. After that, the column behaviors under the compression were modelled with predefined field from the previous step. The effect of the welding process (including flux-core arc welding and submerged arc welding), heating treatment (including preheating and post-weld heat treatment) and geometrical imperfection on the residual stress field and box column strength was investigated and discussed.   

scholarly journals Experimental and Numerical Investigations on the Thermomechanical Behavior of 304 Stainless Steel/Q345R Composite Plate Weld Joint

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3489
Author(s):  
Xiaodong Hu ◽  
Yicheng Yang ◽  
Ming Song
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Weld Joint ◽  
Composite Plate ◽  
Weld Zone ◽  
Welding Process ◽  
Thermomechanical Behavior ◽  
Welding Residual Stress ◽  
304 Stainless Steel ◽  
Von Mises

In this study, the welding process of 304 stainless steel/Q345R low alloy steel composite plate is modeled by experimental and finite element methods to study the complex thermomechanical behavior. The residual stress and microstructure evolution of composite plate in the welding process are also investigated. The welding thermal cycle curve and residual stress distribution at the joint are obtained by using thermocouple and blind-hole methods. Optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to investigate the evolution of microstructure, morphology, and element diffusion of the joint. The results show that the maximum von Mises welding residual stress is 312 MPa, which is located in the bottom of the start point of the weld zone. The residual stress gradually decreases and tends to be stable along the direction from the weld to the base metal. In addition, a residual stress discontinuity is found at the interface between the bimetal. It is also found that the closer it is to the weld joint, the more uniform is the austenite distribution and the smaller are the grain sizes.

Numerical Simulation and Optimization of the YKK355-4 Motor Shaft Welding Structure

2012 ◽  
Vol 442 ◽  
pp. 134-138
Author(s):  
Yi Xin Shi ◽  
Yu Long Shen ◽  
Wen Hui Pan ◽  
Ji Pu Liu
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Residual Stress ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Welding Deformation ◽  
Welding Quality ◽  
Motor Shaft ◽  
Simulation And Optimization ◽  
Actual Use

Motor shaft is an important component of the electromotor. In the process of motor shaft producing, the motor shaft and the rib plates are usually connected by welding. While in actual use, the structure of the motor shaft may often fracture as a result of the welding, in order to solve the above problem, the structure of YKK355-4 motor shaft and rib plates are modeled and analyzed by using finite element method, and then an optimization on the welding process and shaft structure is performed. By comparison, it is safe to conclude that the welding on both sides at the same time can reduce obviously the welding residual stress and welding deformation and the overall welding quality can be effectively enhanced under the adoption of a 3mm chamfer transition in the connection.

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