scholarly journals Residual stress estimation in defect assessment procedures at weld toe and away locations on girth welds: Review of key parameters

2021 ◽  
Vol 111 ◽  
pp. 102848
Author(s):  
Sachin Bhardwaj ◽  
R.M. Chandima Ratnayake
Keyword(s):  
Residual Stress ◽  
Defect Assessment ◽  
Weld Toe ◽  
Stress Estimation ◽  
Girth Welds ◽  
Assessment Procedures

Pressure Correction Factor for Strain Capacity Predictions Based on Curved Wide Plate Testing

2012 ◽  
Author(s):  
Matthias Verstraete ◽  
Wim De Waele ◽  
Rudi Denys ◽  
Stijn Hertelé
Keyword(s):  
Correction Factor ◽  
Large Scale ◽  
Strain Capacity ◽  
Defect Assessment ◽  
Ductile Crack Growth ◽  
Large Scale Testing ◽  
Weld Defect ◽  
Girth Welds ◽  
Assessment Procedures ◽  
Tensile Strain Capacity

Strain-based girth weld defect assessment procedures are essentially based on large scale testing. Ever since the 1980’s curved wide plate testing has been widely applied to determine the tensile strain capacity of flawed girth welds. However, the effect of internal pressure is not captured in curved wide plate testing. Accordingly, unconservative predictions of strain capacity occur when straightforwardly transferred to pressurized pipes. To address this anomaly, this paper presents results of finite element simulations incorporating ductile crack growth. Simulations on homogeneous and girth welded specimens indicate that a correction factor of 0.5 allows to conservatively predict the strain capacity of a pressurized pipe through wide plate testing under the considered conditions.

A Full-Field Residual Stress Profile Estimation Scheme for Pipe Girth Welds

2012 ◽  
Author(s):  
Shaopin Song ◽  
Pingsha Dong ◽  
Jinmiao Zhang
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stress Distribution ◽  
Stress Profile ◽  
Distribution Characteristics ◽  
Full Field ◽  
Residual Stress Profile ◽  
Weld Toe ◽  
Estimation Scheme ◽  
Girth Welds

For supporting fitness-for-service (FFS) assessment, this paper presents a method for providing a full field description of through-thickness residual stress profiles for pipe girth welds, beyond weld locations (e.g., at weld centerline and weld toe). The paper starts with a brief introduction of the finite element modeling procedure used in this study. Experimental validations are performed for a pipe weld geometry on which detailed experimental data have recently become available in the literature. Then, a large number of parametric residual stress analyses are performed to identify key parameters that govern through-thickness residual stress distribution characteristics. These parameters are not only shown to uniquely contribute to some of the important residual stress distribution characteristics of interest to FFS, but also can be formulated, to the first approximation, using basic mechanics and physics principle. Finally, a detailed application of the proposed full field residual stress estimation scheme is illustrated for various girth weld conditions.

Residual stress estimation of a silicon carbide-Kovar joint

1991 ◽  
Vol 26 (11) ◽  
pp. 2887-2892 ◽  
Author(s):  
Toshihiro Yamada ◽  
Motohiro Satoh ◽  
Akiomi Kohno ◽  
Kazuaki Yokoi
Keyword(s):  
Residual Stress ◽  
Silicon Carbide ◽  
Stress Estimation

Development of a Residual Stress Simulation Benchmark for a Single Bead-on-Plate Weldment

2006 ◽  
Author(s):  
Peter J. Bouchard ◽  
Lyndon Edwards ◽  
Anastasius G. Youtsos ◽  
Roger Dennis
Keyword(s):  
Residual Stress ◽  
Assessment Procedure ◽  
Defect Assessment ◽  
Best Estimate ◽  
Weld Residual Stress ◽  
Single Bead ◽  
Stress Prediction ◽  
Stainless Steel Bead ◽  
Stress Simulation ◽  
Network Project

Finite element weld residual stress modelling procedures involve complex non-linear analyses where many assumptions and approximations have to be made by the analyst. Weld modelling guidelines for inclusion in the R6 defect assessment procedure are in preparation and will be accompanied by a series of validation benchmarks that can be used to evaluate the accuracy of weld modelling procedures and assess their suitability for use in fracture assessments. It is intended to base one of the benchmarks on a stainless steel bead-on-plate weldment that has been extensively studied by members of Task Group 1 of the NeT European Network project. This paper uses round robin residual stress measurements from the NeT project to derive a statistically based ‘best estimate’ distribution of transverse stress passing through the wall-section at mid-length of the bead-on-plate weldment. The accuracy of a state-of-the-art residual stress prediction is benchmarked against the best estimate measurements using a root mean square error analysis and comparisons of decomposed components of stress. The appropriateness of using the predicted residual stresses in fracture assessments is assessed by comparing stress intensity factors based on the measured and predicted distributions of stress. The results from these studies will be used to help establish accuracy targets and acceptance criteria for the welding benchmark.

scholarly journals Residual Stress State of X65 Pipeline Girth Welds Before and After Local and Furnace Post Weld Heat Treatment

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Yao Ren ◽  
Anna Paradowska ◽  
Bin Wang ◽  
Elvin Eren ◽  
Yin Jin Janin
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Residual Stresses ◽  
Outer Surface ◽  
Post Weld Heat Treatment ◽  
Pipe Length ◽  
Stress Profiles ◽  
Girth Welds ◽  
Welded Pipe ◽  
Weld Heat

This research investigated the effects of global (in other words, furnace-based) and local post weld heat treatment (PWHT) on residual stress (RS) relaxation in API 5L X65 pipe girth welds. All pipe spools were fabricated using identical pipeline production procedures for manufacturing multipass narrow gap welds. Nondestructive neutron diffraction (ND) strain scanning was carried out on girth welded pipe spools and strain-free comb samples for the determination of the lattice spacing. All residual stress measurements were carried out at the KOWARI strain scanning instrument at the Australian Nuclear Science and Technology Organization (ANSTO). Residual stresses were measured on two pipe spools in as-welded condition and two pipe spools after local and furnace PWHT. Measurements were conducted through the thickness in the weld material and adjacent parent metal starting from the weld toes. Besides, three line-scans along pipe length were made 3 mm below outer surface, at pipe wall midthickness, and 3 mm above the inner surface. PWHT was carried out for stress relief; one pipe was conventionally heat treated entirely in an enclosed furnace, and the other was locally heated by a flexible ceramic heating pad. Residual stresses measured after PWHT were at exactly the same locations as those in as-welded condition. Residual stress states of the pipe spools in as-welded condition and after PWHT were compared, and the results were presented in full stress maps. Additionally, through-thickness residual stress profiles and the results of one line scan (3 mm below outer surface) were compared with the respective residual stress profiles advised in British Standard BS 7910 “Guide to methods for assessing the acceptability of flaws in metallic structures” and the UK nuclear industry's R6 procedure. The residual stress profiles in as-welded condition were similar. With the given parameters, local PWHT has effectively reduced residual stresses in the pipe spool to such a level that it prompted the thought that local PWHT can be considered a substitute for global PWHT.

scholarly journals Feasibility of Residual Stress Nondestructive Estimation Using the Nonlinear Property of Critical Refraction Longitudinal Wave

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Yu-Hua Zhang ◽  
Xin-Xin Li ◽  
Xiang-Hong Wang ◽  
Zhen-Feng Huang ◽  
Han-Ling Mao ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Wave Velocity ◽  
Nonlinear Coefficient ◽  
Quantitative Information ◽  
Difficult Problem ◽  
Nonlinear Property ◽  
Deformation State ◽  
Stress Estimation ◽  
Nondestructive Estimation

Residual stress has significant influence on the performance of mechanical components, and the nondestructive estimation of residual stress is always a difficult problem. This study applies the relative nonlinear coefficient of critical refraction longitudinal (LCR) wave to nondestructively characterize the stress state of materials; the feasibility of residual stress estimation using the nonlinear property of LCR wave is verified. The nonlinear ultrasonic measurements based on LCR wave are conducted on components with known stress state to calculate the relative nonlinear coefficient. Experimental results indicate that the relative nonlinear coefficient monotonically increases with prestress and the increment of relative nonlinear coefficient is about 80%, while the wave velocity only decreases about 0.2%. The sensitivity of the relative nonlinear coefficient for stress is much higher than wave velocity. Furthermore, the dependence between the relative nonlinear coefficient and deformation state of components is found. The stress detection resolution based on the nonlinear property of LCR wave is 10 MPa, which has higher resolution than wave velocity. These results demonstrate that the nonlinear property of LCR wave is more suitable for stress characterization than wave velocity, and this quantitative information could be used for residual stress estimation.

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