Residual Stress Evaluation of Small Diameter Stainless Steel Piping by Experimental Measurements and Finite Element Analysis

2014 ◽  
Author(s):  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller ◽  
John V. Mullen
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Axial Stress ◽  
Large Diameter ◽  
Small Diameter ◽  
Thick Wall ◽  
Outer Diameter ◽  
Thin Wall ◽  
The Impact

Residual stresses within stainless steel pipe welds may impact both component inspections and in-service cracking. Various investigators have examined piping residual stresses in large diameter piping using both finite element modeling and experimental techniques, but limited information is available for small diameter piping. This investigation uses both experimental methods and analytical modeling to evaluate the impact of welding on the residual stresses along the inner diameter (ID) of two small diameter pipe specimens. Results of the investigation showed that tensile axial residual stresses were observed in the heat affected zone (HAZ) along the ID of the thin-wall pipe specimen with distinct regions of tensile and compressive axial stress which correlate well with the location where the last weld segments of the final weld pass were deposited. Higher stresses were also observed in the HAZ on the side where the final weld pass was deposited. By contrast, testing of the thick-wall pipe specimen showed significantly lower levels of tensile stresses along the pipe ID with the higher stress regions being biased toward the pipe outer diameter (OD).

Evaluation of Residual Stresses Induced by Repairs to Small Diameter Stainless Steel Pipe Welds

2015 ◽  
Author(s):  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller ◽  
John V. Mullen
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Large Diameter ◽  
Small Diameter ◽  
Steel Pipe ◽  
Limited Information ◽  
Diameter Pipe ◽  
Stainless Steel Pipe ◽  
Lower Magnitude ◽  
The Impact

Residual stresses within stainless steel pipe welds may cause or exacerbate in-service cracking. Significant investigative efforts have been devoted to the examination of piping residual stresses in large diameter piping using both finite element modeling and experimental techniques, but limited information is available for small diameter piping. Even less information is available for small diameter piping welds which have been repaired or re-worked during initial fabrication. This investigation used both experimental methods and analytical modeling to assess the impact of repair welding during initial fabrication on the residual stresses along the inner diameter (ID) of small diameter pipe specimens. The investigation showed that tensile axial residual stresses were located in the heat affected zone (HAZ) along the ID of the pipe specimens adjacent to regions which were excavated and re-welded. Such repair welds were also shown to markedly increase the magnitude of the tensile axial residual stresses for weld configurations which otherwise had lower magnitude residual stresses.

Prediction of Residual Stress Distributions in Welded Sections of P92 Pipes with Small Diameter and Thick Wall based on 3D Finite Element Simulation

2015 ◽  
Vol 34 (3) ◽  
Author(s):  
Xiaowei Wang ◽  
Jianming Gong ◽  
Yanping Zhao ◽  
Yanfei Wang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Small Diameter ◽  
Fe Analysis ◽  
Thick Wall ◽  
Fe Model ◽  
Stress Distributions ◽  
Residual Stress Field ◽  
Heat Treated

AbstractThis study used ABAQUS finite element (FE) software to investigate the residual stress distributions of P92 welded pipes in both the as-weld and post weld heat treated (PWHT) condition. Sequential coupling quasi-static thermo-mechanical in conjunction with moving double ellipsoidal heat source and an element add/remove technique to simulate deposition of new weld material, are combined in the 3D FE analysis. To validate the simulation results, the residual stresses in axial direction at the surface of pipe were measured by X-ray diffraction technique and compared with the results of FE analysis. Detailed characteristic distributions of the residual stresses are discussed. Results show that the FE model can predict the residual stress distributions satisfactorily. Highest residual stresses on the outer surface are found in the last weld bead to be deposited. And the highest tensile residual stress for the full welded section take place in heat affected zone (HAZ) near the middle thickness. Larger residual sstress can be found around the welding start point along the pipe circumference. Comparison of heat treated specimen and untreated specimen illustrates that PWHT has a strong effect on the residual stress field.

Residual Stress Analyses of a Multi-Pass Girth Weld: 3-D Special Shell Versus Axisymmetric Models

2000 ◽  
Vol 123 (2) ◽  
pp. 207-213 ◽  
Author(s):  
P. Dong
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Wall Thickness ◽  
Stress Component ◽  
Thick Wall ◽  
Hole Drilling ◽  
Thin Wall ◽  
Weld Residual Stress ◽  
Stress Analyses

In this paper, detailed weld residual stress analyses are presented for a typical multi-pass girth weld in Type 316L stainless steel pipe with r/t ratio of 25. Advanced finite element procedures were used to simulate the residual stress development under controlled welding conditions associated with weld mock-ups. Both axisymmetric and 3-D special shell element models were used to reveal local residual stress details and global residual stress characteristics in the girth weld. Residual stress measurements using hole-drilling method were conducted for model validation on the laboratory weld mock-up welds. A good agreement between finite element predictions and experimental measurements were obtained. The major findings include: (a) Axial residual stresses within and near the weld area exhibit a strong bending feature across the pipe wall thickness, while the hoop residual stresses showed a much less variation through the wall thickness. (b) Some periodic variation of the residual stresses is present along the pipe circumference near the weld, particularly for the axial residual stress component. Such a variation tends to become more pronounced in thick wall than in thin wall girth welds. A 3-D model is essential to adequately capture such 3-D features in residual stress distributions. (c) A rapid variation in weld residual stresses can be seen at start/stop positions, where a high magnitude of axial residual stresses is present in both tension and compression.

Effects of Repair Weld Length on Residual Stress Distribution

2001 ◽  
Vol 124 (1) ◽  
pp. 74-80 ◽  
Author(s):  
P. Dong ◽  
J. Zhang ◽  
P. J. Bouchard
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Axial Stress ◽  
Base Material ◽  
Shell Element ◽  
Element Model ◽  
Outer Diameter ◽  
Stress Distributions ◽  
Axial Tensile

This paper discusses residual stress distributions induced by repairing a stainless steel girth weld in a 19-mm thick pipe of outer diameter 541 mm. In particular, the effects of repair weld circumferential length are examined using finite element modeling. Results for three different repair lengths are presented having circumferential angular spans of 20 deg (short repair), 57 deg (medium repair), and 114 deg (long repair). A special 3-D shell element model is used which facilitates the simulation of multi-pass welds in 3-D piping components. The results shed light on a number of important 3-D residual stress features associated with repairs. Outer surface axial residual stresses in the weld and adjacent base material are tensile along the length of the repair, reach maxima values near the arc start/stop positions, and then drop into compression beyond the repair ends. The short repair develops the highest axial tensile stresses due to the overlay of start/stop effects. The circumferentially remote residual stresses are unaffected by the repairs. At midlength of the repair, profiles of axial stress along the pipe show tensile peaks at ≈40 mm away from the weld centerline; these peaks decrease in magnitude with increasing repair length. However, the medium repair axial stresses show the greatest range of influence along the pipe. The pre-existing original girth weld residual stresses have very little effect on the repair residual stress characteristics. Finally, residual stress measurements on mock-up components are discussed which confirm the validity of the finite element methods used.

scholarly journals Research on on-line ultrasonic testing of small diameter thin wall stainless steel straight welded pipe

2021 ◽  
Vol 1820 (1) ◽  
pp. 012086
Author(s):  
Huaishu Hou ◽  
Ding Lu ◽  
Shiwei Zhang ◽  
Yi Zhang ◽  
Chaolei Cheng
Keyword(s):  
Stainless Steel ◽  
Ultrasonic Testing ◽  
Small Diameter ◽  
Thin Wall ◽  
On Line ◽  
Welded Pipe ◽  
Wall Stainless Steel

scholarly journals Elastic Modulus and Elasticity Ratio of Malignant Breast Lesions with Shear Wave Ultrasound Elastography: Variations with Different Region of Interest and Lesion Size

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1015
Author(s):  
Antonio Bulum ◽  
Gordana Ivanac ◽  
Eugen Divjak ◽  
Iva Biondić Špoljar ◽  
Martina Džoić Dominković ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Large Diameter ◽  
Small Diameter ◽  
Shear Wave Elastography ◽  
Lesion Size ◽  
Ultrasound Elastography ◽  
Breast Lesions ◽  
Malignant Breast ◽  
The Impact

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.

Study on Crashworthiness Characteristics of Several Concentric Thin Wall Tubes

2010 ◽  
Author(s):  
Parisa Hosseini Tehrani ◽  
Sajad Pirmohammad
Keyword(s):  
Finite Element ◽  
Optimum Combination ◽  
Thick Wall ◽  
Thin Wall ◽  
Finite Element Program ◽  
Linear Dynamic ◽  
Wall Structures ◽  
Moving Body ◽  
Oblique Loading ◽  
Element Program

There is a growing interest in the use of thin-wall structures as a means of absorbing the kinetic energy of a moving body. Multi-layered thin-wall structures are more efficient and lighter than thick-wall structures, and show better crashworthiness characteristics. In this task, several concentric aluminum thin wall tubes as energy absorber under axial and oblique loading are studied and optimum combination of these tubes is presented. The weight of the tubes is optimized while crashworthiness of tubes is not compromised. The commercial finite element program LS-DYNA that offers non-linear dynamic simulation capabilities was used in this study.

Numerical Simulation to Study the Effect of Arc Travelling Speed and Welding Sequences on Residual Stresses in Welded Sections of New Ferritic P92 Pipes

2016 ◽  
Vol 35 (2) ◽  
pp. 121-128 ◽  
Author(s):  
Xiaowei Wang ◽  
Jianming Gong ◽  
Yanping Zhao ◽  
Yanfei Wang ◽  
Zhiqiang Ge
Keyword(s):  
Residual Stresses ◽  
Power Plants ◽  
Small Diameter ◽  
Good Combination ◽  
Thick Wall ◽  
P92 Steel ◽  
Welding Technology ◽  
Symmetrical Distribution ◽  
Mechanical And Physical Properties ◽  
Welding Sequences

AbstractNew ferritic P92 steel is widely used in modern power plants due to its good combination of mechanical and physical properties. However, cracks are often formed in the welded sections during the fabrication or service. In order to ensure the structure integrity, the effects of residual stresses need to be considered. The objective of this paper is to investigate the influence of arc travelling speed and welding sequences on the residual stresses distribution in the welded sections of P92 pipes by finite element method (FEM). Results show that arc travelling speed and welding sequences have great effects on residual stresses distribution. With the arc travelling speed increasing, the residual stresses increase. Meanwhile, welding sequences of case B present smaller residual stresses and more symmetrical distribution of residual stresses at the weld centre line. Therefore, using slower arc travelling speed and case B welding sequences can be useful to decrease the residual stresses, which provides a reference for optimizing the welding technology and improving the fabrication process of new ferritic P92 welded pipes with small diameter and thick wall.

Weld Residual Stress in Large Diameter Nuclear Nozzles

2011 ◽  
Author(s):  
Tao Zhang ◽  
F. W. Brust ◽  
Gery Wilkowski
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Nuclear Power ◽  
Kinematic Hardening ◽  
Large Diameter ◽  
Thick Wall ◽  
Isotropic Hardening ◽  
Residual Stress Field ◽  
Mixed Hardening ◽  
Weld Residual Stress

Weld residual stresses in nuclear power plant can lead to cracking concerns caused by stress corrosion. These are large diameter thick wall pipe and nozzles. Many factors can lead to the development of the weld residual stresses and the distributions of the stress through the wall thickness can vary markedly. Hence, understanding the residual stress distribution is important to evaluate the reliability of pipe and nozzle joints with welds. This paper represents an examination of the weld residual stress distributions which occur in various different size nozzles. The detailed weld residual stress predictions for these nozzles are summarized. Many such weld residual stress solutions have been developed by the authors in the last five years. These distributions will be categorized and organized in this paper and general trends for the causes of the distributions will be established. The residual stress field can therefore feed into a crack growth analysis. The solutions are made using several different constitutive models such as kinematic hardening, isotropic hardening, and mixed hardening model. Necessary fabrication procedures such as repair, overlay and post weld heat treatment are also considered. Some general discussions and comments will conclude the paper.

Dynamic Responses of Buried Pipelines Under Impact Loading Caused by Landslide

2012 ◽  
Vol 204-208 ◽  
pp. 3476-3479 ◽  
Author(s):  
Xiu Xing Zhu ◽  
Shi Feng Xue ◽  
Xing Hua Tong ◽  
Chuan Qi Liu
Keyword(s):  
Impact Loading ◽  
Impact Force ◽  
Large Diameter ◽  
Influence Factors ◽  
Dynamic Responses ◽  
Thin Wall ◽  
Buried Pipelines ◽  
Steel Pipes ◽  
Mountainous Regions ◽  
The Impact

Cases of pipeline damage caused by landslide are common in coastal or mountainous regions, where the design of buried pipelines should be improved in order to reduce the risk of damage or failure. Dynamic responses of large diameter thin wall steel pipes under impact loading were analyzed using a nonlinear contact model of pipe-soil coupling in this paper. Several influence factors were studied, such as the impact velocity of rockfall, buried depth of pipeline, ratio of diameter to thickness and style of soil. The results show that an ellipsoid induces much more impact force than a sphere which has the same volume, and the larger one in volume have greater impact force for two spheres. Dangerous compressive areas of pipeline occupy 1/6 of the whole area, so the pipelines subject to landslide occur local failure. Based on results, some useful suggestions for the design of pipelines in landslide region are given

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