scholarly journals Welding Procedure Qualification Record (WPQR) for Welds Fabricated At Proximity

2021 ◽  
Author(s):  
Sachin Bhardwaj ◽  
R.M. Chandima Ratnayake
Keyword(s):  
Welded Joints ◽  
Mechanical Test ◽  
Offshore Structures ◽  
Mechanical Tests ◽  
Design Engineers ◽  
Weld Toe ◽  
Research Findings ◽  
Tubular Sections ◽  
Girth Welds ◽  
Welding Procedure

Abstract Maintaining minimum allowable distance between proximity welds has always been considered a subject of debate between design engineers, welding engineers/inspectors and fabricators/engineering contractors. The scattered nature of guidelines available in welding codes and standards for maintain minimum allowable distance pose a significant challenge in the welding procedure and inspection criteria development process. This is especially critical for complex welded joints on submerged sections of offshore structures, in compact layouts/branched connections of topside piping components, and on topside structural joints (depending on the complexity). This manuscript presents the findings of an experimental study that was performed by fabricating two girth welds at a proximity on an S355 steel tubular section having diameter of 219.1 mm and thickness of 8.18 mm. Proximity girth welds were fabricated on S355 tubular sections at three different distances between their weld toe as 5, 10 & 15mm respectively using two different welding procedures. Welding procedure qualification record (WPQR) was performed, and all prescribed mechanical tests were recorded as per NORSOK M-101, a structural steel fabrication code. Although all results from mechanical test met minimum specified values as defined in the NORSOK code, research findings revealed noticeable difference in Charpy and hardness values for proximity region between adjacent welds. Considerable changes in final microstructure morphology were observed between proximity welds due to successive thermal cycles. These observations can form basis for future welding procedure qualification of critical welded joints, especially for proximity welds on critical welded joints of offshore structures and welds fabricated during replacement/repair procedures in compact piping layouts.

Examinations Regarding the Sour Gas Resistance of Girth Welds Carried Out on API Grade X80 Seamless Pipe Steel (Heavy Wall)

2014 ◽  
Author(s):  
Diana Toma ◽  
Jörg Wiebe ◽  
Dorothee Niklasch ◽  
Ashraf Koka
Keyword(s):  
High Strength ◽  
Mechanical Tests ◽  
Carbon Equivalent ◽  
Welding Parameters ◽  
Line Pipe ◽  
Sea Bed ◽  
Steel Grades ◽  
Girth Welds ◽  
Welding Procedure ◽  
Sour Gas

Various accessories such as buckle arrestors and J-lay collars are needed in some cases to successfully lay and secure an offshore pipeline on the sea bed. For such applications the using of high strength seamless pipes in Grade X70 and X80 with heavy wall are necessary. However, there is only small information regarding the welding procedure for such grades in heavy wall dimensions. In comparison to steels used for lower strength level, the chemistry of high strength steel pipes includes higher amounts of micro-alloying elements as well as requires a more complex heat treatment. Due to the higher carbon equivalent these steel grades react more sensitive on heat input during welding. Consequently, the range of welding parameters which ensure suitable mechanical properties has to be adapted. This article presents the results of weldability trials carried out on seamless API X80 heavy wall (> 50mm) line pipe. The welding trials were performed using different preheating temperatures and heat inputs followed by microstructure investigations and mechanical tests of the multilayer welds. The sour gas resistance has to be demonstrated by SSC-tests because it stays challenging to guarantee values below 250 HV10.

scholarly journals Generalized SCF Formula of Out-Of-Plane Gusset Welded Joints and Assessment of Fatigue Life Extension by Additional Weld

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1249
Author(s):  
Yixun Wang ◽  
Yuxiao Luo ◽  
Yuki Kotani ◽  
Seiichiro Tsutsumi
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Welded Joints ◽  
Life Extension ◽  
Leg Length ◽  
Notch Stress ◽  
Out Of Plane ◽  
Weld Toe ◽  
Effective Notch Stress ◽  
Geometric Effects

The existing S-N curves by effective notch stress to assess the fatigue life of gusset welded joints can result in reduced accuracy due to the oversimplification of bead geometries. The present work proposes the parametric formulae of stress concentration factor (SCF) for as-welded gusset joints based on the spline model, by which the effective notch stress can be accurately calculated for fatigue resistance assessment. The spline model is also modified to make it applicable to the additional weld. The fatigue resistance of as-welded and additional-welded specimens is assessed considering the geometric effects and weld profiles. The results show that the error of SCFs by the proposed formulae is proven to be smaller than 5%. The additional weld can increase the fatigue life by as great as 9.4 times, mainly because the increasing weld toe radius and weld leg length lead to the smaller SCF. The proposed series of S-N curves, considering different SCFs, can be used to assess the welded joints with various geometric parameters and weld profiles.

Full Scale Fatigue Experiment on Submarine Pipelines

2014 ◽  
Vol 633-634 ◽  
pp. 659-664 ◽  
Author(s):  
Zong Tao Fang ◽  
De Yu Tang ◽  
Yan Hua Hu ◽  
Hu Li Niu
Keyword(s):  
Welded Joints ◽  
Fatigue Property ◽  
Full Scale ◽  
Small Scale ◽  
Test Machine ◽  
Butt Joints ◽  
Weld Toe ◽  
Small Test ◽  
Weld Root ◽  
Fatigue Experiment

This paper focus on fatigue problem of submarine pipelines, four points bending full scale fatigue experiment were conducted on X65 pipelines butt joints specimens, utilizing pipeline full scale fatigue test machine developed by CNPC. Meanwhile contrast test was also carried out on small specimens. The results show that the fatigue strength of full scale welded joints is lower than the small scale joints. Owing to having no regard for the influence of residual stress and size effect, the small test would provide dangerous results. The fatigue property of full scale welded joints only meets the requirement of DNV C203 W3 curve, and meets the needs of DNV C203 F3 curve basically while not meet BS 7608 F2 curve’s requirements which relatively demand higher. Weld toe and geometric discontinuous near weld root is the weak point for the whole welded joints.

Features of ultrasonic control of butt welded joints of polyethylene pipes

2020 ◽  
pp. 46-52
Author(s):  
N.P. Aleshin ◽  
D.M. Kozlov ◽  
L.YU. Mogilner
Keyword(s):  
Quality Control ◽  
Welded Joints ◽  
Ultrasonic Testing ◽  
Ultrasonic Inspection ◽  
Mechanical Tests ◽  
Ultrasonic Control ◽  
Lack Of Fusion ◽  
Polyethylene Pipes ◽  
End To End

The reliability of ultrasonic testing (UT) of the quality of welded joints of polyethylene pipelines, made end-to-end with a heated tool, is considered in comparison with mechanical tests and radiography. The greatest detection of solid defects is provided by ultrasonic inspection with the use of chord tipe probes (not less than 90 %). When detecting defects translucent for ultrasound (lack of penetration, lack of fusion, etc.), the reliability decreases to 70÷80 %. Keywords: welding, polyethylene pipeline, quality control, ultrasonic testing, chord tipe probe. [email protected]

Anticorrosion Protection of Welded Joints of Oil Pipelines

2018 ◽  
Vol 284 ◽  
pp. 1129-1133
Author(s):  
M.A. Ivanov ◽  
P.A. Danilkin ◽  
V.D. Kvashnin
Keyword(s):  
Welded Joints ◽  
High Speed ◽  
Operational Reliability ◽  
Polymer Coatings ◽  
Mechanical Tests ◽  
Technical Standards ◽  
Oil Companies ◽  
Oil Pipelines ◽  
Metal Properties ◽  
Protection Coating

Currently, a problem of destruction of field and interfiled pipelines is topical. One of effective ways to increase an operational reliability of pipes is to protect them with different coatings. To protect the inner surface of oil pipelines the polymer coatings are used which cover the full length except the end sections – zones of mounted welded joints. Oil companies are interested in development of a technology of metal coating applying to the end sections, which provides both reliability of protection system of inner surfaces of pipes, and workability and high speed of mounting of pipelines. This paper shows the analysis of protection methods of pipeline end sections. The tests of metallized coatings are held. We identified the significant shortcomings of metallized coatings. There is a held experiment on applying of corrosion resistant coating by surfacing. There are the calculated heating zones while the surfacing operation. We defined the minimum necessary length of section for applying the protection coating. A chemical analysis showed that the expected structure in a surfaced coating is an austenite with inclusions of ferrite and martensite. Metallographic research showed that the protection layer is fully melted with a base metal of a pipe and represents a homogeneous structure without pores and slag inclusions. Mechanical tests confirmed the compliance of pipe metal properties to the requirements of normative and technical standards.

On the Mechanics of Residual Stresses in Girth Welds

2006 ◽  
Vol 129 (3) ◽  
pp. 345-354 ◽  
Author(s):  
P. Dong
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Relative Importance ◽  
Stress Distributions ◽  
Unified Framework ◽  
Joint Geometry ◽  
Weld Residual Stress ◽  
Girth Welds ◽  
Welding Procedure

In this paper, some of the important controlling parameters governing weld residual stress distributions are presented for girth welds in pipe and vessel components, based on a large number of residual stress solutions available to date. The focus is placed upon the understanding of some of the overall characteristics in through-wall residual stress distributions and their generalization for vessel and pipe girth welds. In doing so, a unified framework for prescribing residual stress distributions is outlined for fitness-for-service assessment of vessel and pipe girth welds. The effects of various joint geometry and welding procedure parameters on through thickness residual stress distributions are also demonstrated in the order of their relative importance.

scholarly journals Use of 3D Scan of Weld Joint in Finite Element Analysis and Stochastic Analysis of Hot-Spot Stresses in Tubular Joint for Fatigue Life Estimation

2019 ◽  
Author(s):  
Mikkel L. Larsen ◽  
Vikas Arora ◽  
Marie Lützen ◽  
Ronnie R. Pedersen ◽  
Eric Putnam
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Welded Joints ◽  
Hot Spot ◽  
Strain Range ◽  
Fe Model ◽  
Design Codes ◽  
Element Analysis ◽  
Hot Spot Stress ◽  
Weld Toe

Abstract Several methods for modelling and finite element analysis of tubular welded joints are described in various design codes. These codes provide specific recommendations for modelling of the welded joints, using simple weld geometries. In this paper, experimental hot-spot strain range results from a full-scale automatically welded K-node test are compared to corresponding finite element models. As part of investigating the automatically welded K-joint, 3D scans of the weld surfaces have been made. These scans are included in the FE models to determine the accuracy of the FE models. The results are compared to an FE model with a simple weld geometry based on common offshore design codes and a model without any modelled weld. The results show that the FE model with 3D scanned welds is more accurate than the two simple FE models. As the weld toe location of the 3D scanned weld is difficult to locate precisely in the FE model and as misplacement of strain gauges are possible, stochastic finite element modelling is performed to analyse the resulting probabilistic hot-spot stresses. The results show large standard deviations, showing the necessity to evaluate the hot-spot stress method when using 3D scanned welds.

Optimization of Osteosynthesis Positioning in Mandibular Body Fracture Management using Numerical Finite Element Method Simulation and Polymeric Model Testing

2021 ◽  
Author(s):  
Omid Daqiq ◽  
Fred W. Wubs ◽  
Ruud R. M. Bos ◽  
Baucke van Minnen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mechanical Test ◽  
Body Height ◽  
Finite Element Method Simulation ◽  
Mechanical Tests ◽  
Body Fracture ◽  
Fracture Management ◽  
Mandibular Body ◽  
Element Method

Abstract The study aims to optimise surgical management for mandibular body fractures by application of finite element method (FEM) with verification from polymeric model tests. The study investigates two issues regarding the application of osteosynthesis plates for mandibular body fractures: the effect of miniplate positioning and mandibular body height decrease. Computed tomography (CT) images of cadaveric mandibles with heights of resp. 21, 15, and 10 mm were used to create a FEM-model with a unilateral straight-line fracture, fixated with a standard commercially available 6-hole 2 mm titanium miniplate. Outcomes were compared with a series of mechanical tests with polymeric models fixed in a customized device and loaded with a mechanical test bench. Firstly, the study illustrates that the optimal plate position appears to be the upper border. Secondly, lower mandibular height increases instability and requires a stronger fixation. Thirdly, optimal fracture reduction is essential for gaining stability. In conclusion, FEM and polymeric testing outcomes of unilateral non-comminuted fractures were highly comparable to the current opinions in mandibular fracture treatment. In future, the FEM may be used to predict the treatment of more complex fractures. However, more analysis needs to be conducted to say whether FEM alone is sufficient for fracture analysis.

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