Comparison radiographic and automated ultrasonic inspection of pipeline tie-in welds

International Nuclear Information System (INIS)

Connelly, T.; Gross, B.

2007-01-01

In recent years the use of automated ultrasonic inspection (AUT) for pipeline girth welds has seen rapid growth and is now used almost exclusively for all gas metal arc welding (GMAW) girth weld inspection. The following paper reviews some of the major features of ultrasonic inspection by comparison to conventional Film Radiography (RT) and reviews the use of ultrasonic inspection for pipeline and tie-in welds. (author)

Mechanical properties of API X80 steel pipe joints welded by Flux Core Arc Weld Process; Propriedades mecanicas de juntas de tubos de aco API X80 soldadas com arame tubulares

Energy Technology Data Exchange (ETDEWEB)

Ordonez, Robert E. Cooper; Silva, Jose Hilton F.; Trevisan, Roseana E. [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Fabricacao

2003-07-01

Flux Core Arc Welding processes (FCAW) are beginning to be applied in pipeline welds, however, very limited experimental data regarding mechanical properties of pipeline weld joints with these processes are available in the literature. In this paper, the effects of preheat temperature and type of FCAW on mechanical properties (microhardness and tensile strength) of API X80 weld joint steel are presented. FCAW processes with gas protection and self-shielded were used. Multipasses welding were applied in 30'' diameter and 0,625'' thickness tubes. Influence factors were: FCAW type and preheat temperature. Acceptance criteria of welded joints were evaluated by API 1104 standard for tensile strength test and ASTM E384-99 for microhardness test. The results obtained showed that FCAW type and preheat temperature have no influence on mechanical properties of API X80 joint steel. (author)

Residual stress measurements in coil, linepipe and girth welded pipe

International Nuclear Information System (INIS)

Law, M.; Prask, H.; Luzin, V.; Gnaeupel-Herold, T.

2006-01-01

Residual stresses in gas pipelines come from forming operations in producing the coil and pipe, seam welding the pipe, and girth welding pipes together to form a gas pipeline. Welding is used extensively in gas pipelines, the welds are made without post weld heat treatment. The three normal stresses were measured by neutron diffraction for three types of sample: coil, unwelded rings cut from the pipe made from this coil, and girth welded rings cut from linepipe. All three specimens came from three thicknesses of manufacture (5.4, 6.4, and 7.1 mm). The welds are manual metal arc cellulosic electrode welds made in X70 linepipe, these were measured at 5 through-thickness positions at 19 locations (from the center of the weld up to 35 mm away from the weld) with a spatial resolution of 1 mm 3 . The coil and unwelded rings were measured at the same five through-thickness positions

Digitization of radiographic inspection for pipeline girth welded joints

International Nuclear Information System (INIS)

Uemura, Shimpei

2016-01-01

In radiographic inspection for the girth welded joints of natural gas pipeline, film radiographic testing (FRT) is applied presently in Japan. However, as of July 2016, the work of establishing JIS standard for radiographic inspection with digital detector is in progress. In order to provide users with the merit of digitization as soon as possible, the authors have developed NSDART (Nittetsu-Sumikin digital detector array technology) as a field X-ray inspection system for the girth welded joints of pipeline. This paper reports the required performances discussed in face of development of NSDART, selection of digital detector, and outline of NSDART, and shows part of the radiographic images acquired with NSDART. As required performances, the following were established: (1) required image quality for radiographic image, (2) identifiable minimum wire diameter of transmission meter, (3) density range of radiographic image and value of gradation meter, (4) spatial resolution via Duplex Wire, (5) X-ray generator, (6) real time performance, and (7) display for observing radiographic image. As for the selection of digital detector, flat panel detector was judged to be the most suitable, and its incorporation to NSDART was determined. NSDART devices are composed of a magnet-wheeled self-propelled imaging device, personal computer, controller, and externally installed display for judgment. (A.O.)

Recent changes in code requirements for repair of in-service pipelines by welding

Energy Technology Data Exchange (ETDEWEB)

Bruce, W.A. [Edison Welding Inst., Columbus, OH (United States)

2000-07-01

Corrosion damage on pipelines represents the second most important cause of damage to natural gas pipelines in the United States. The area containing the corrosion damage must be reinforced to prevent the pipeline to rupture and from bulging. The predominant method of reinforcing corrosion damage in cross-country pipelines is to install a full-encirclement repair sleeve. The recent up-date of American Petroleum Institute (API) code requirement for repair of in-service pipelines by welding was published to provide a recommended practice for pipeline maintenance welding. The recent changes to the code are explained. The appendix B to the up-date is intended to alleviate redundancy between API 1104 and API 1107 and the time lag between up-dates, and to address technological advances made in the area of in-service welding. An alternative repair method of deposited weld metal, or weld deposition repair is briefly explained. 9 refs., 5 figs.

The Investigation of Structure Heterogeneous Joint Welds in Pipelines

Directory of Open Access Journals (Sweden)

Lyubimova Lyudmila

2016-01-01

Full Text Available Welding joints of dissimilar steels don’t withstand design life. One of the important causes of premature destructions can be the acceleration of steel structural degradation due to cyclic mechanical and thermal gradients. Two zones of tube from steel 12H18N9T, exhibiting the structural instability at early stages of the decomposition of a supersaturated solid austenite solution, were subjected to investigation. Methods of x-ray spectral and structure analysis, micro hardnessmetry were applied for the research. Made the following conclusions, inside and outside tube wall surfaces of hazardous zones in welding joint have different technological and resource characteristics. The microhardness very sensitive to changes of metal structure and can be regarded as integral characteristic of strength and ductility. The welding processes are responsible for the further fibering of tube wall structure, they impact to the characteristics of hot-resistance and long-term strength due to development of ring cracks in the welding joint of pipeline. The monitoring of microhardness and structural phase conversions can be used for control by changes of mechanical properties in result of post welding and reductive heat treatment of welding joints.

Fatigue assessment of a double submerged arc welded gas pipeline

Energy Technology Data Exchange (ETDEWEB)

Fazzini, Pablo; Otegui, Jose Luis [Universidad Nacional Mar del Plata, Mar del Plata (Argentina). Instituto de Ciencia y Tecnologia de Materiales (INTEMA); Teutonico, Mauricio; Manfredi, Carlos [GIE S.A., Mar del Plata (Argentina)

2005-07-01

An uncommon blowout in a 24'' diameter, 7 mm thick API 5L X52 gas pipeline was due to fracture at the longitudinal double submerged arc weld. Oddly enough for gas pipelines, it was found that fatigue cracks had propagated from a large embedded weld defect of lack of fusion resulting from severe geometrical mismatch between inner and outer weld passes. What makes this failure particularly interesting is that: previous in line inspections failed to detect any defect, no evidence of third party damage was found, and very few large pressure cycles had been recorded during the last 5 years of service, which were believed to be representative of the entire service life of the pipeline. Fatigue tests were carried out to characterize propagation of fatigue cracks in weld metal, it was found that a large Paris exponent made the few large amplitude cycles most contributing to crack propagation. Crack growth path and striation patterns were studied. Fatigue growth was modelled by integrating experimental results and by extrapolating striation spacing in the fracture surface of the failed pipe. Crack growth path and striation patterns were studied. It was found that microstructure discontinuities govern propagation at low {delta}K, but one striation per cycle was produced at large {delta}K, due to a mostly ductile propagation mode. Fatigue growth was modelled by integrating experimental results and by extrapolating striation spacing in the fracture surface of the failed pipe. It was found that in the early life of the line many more large pressure cycles than expected had occurred. Good correspondence between predicted and actual fatigue lives was in this way obtained (author)

Fatigue assessment of a double submerged arc welded gas pipeline

Energy Technology Data Exchange (ETDEWEB)

Fazzini, Pablo; Otegui, Jose Luis [Universidad Nacional Mar del Plata, Mar del Plata (Argentina). Instituto de Ciencia y Tecnologia de Materiales (INTEMA); Teutonico, Mauricio; Manfredi, Carlos [GIE S.A., Mar del Plata (Argentina)

2005-07-01

An uncommon blowout in a 24'' diameter, 7 mm thick API 5L X52 gas pipeline was due to fracture at the longitudinal double submerged arc weld. Oddly enough for gas pipelines, it was found that fatigue cracks had propagated from a large embedded weld defect of lack of fusion resulting from severe geometrical mismatch between inner and outer weld passes. What makes this failure particularly interesting is that: previous in line inspections failed to detect any defect, no evidence of third party damage was found, and very few large pressure cycles had been recorded during the last 5 years of service, which were believed to be representative of the entire service life of the pipeline. Fatigue tests were carried out to characterize propagation of fatigue cracks in weld metal, it was found that a large Paris exponent made the few large amplitude cycles most contributing to crack propagation. Crack growth path and striation patterns were studied. Fatigue growth was modelled by integrating experimental results and by extrapolating striation spacing in the fracture surface of the failed pipe. Crack growth path and striation patterns were studied. It was found that microstructure discontinuities govern propagation at low {delta}K, but one striation per cycle was produced at large {delta}K, due to a mostly ductile propagation mode. Fatigue growth was modelled by integrating experimental results and by extrapolating striation spacing in the fracture surface of the failed pipe. It was found that in the early life of the line many more large pressure cycles than expected had occurred. Good correspondence between predicted and actual fatigue lives was in this way obtained (author)

Anti-Thixotropic Analysis of Pipeline Metal Losses in Welded ...

African Journals Online (AJOL)

Anti-Thixotropic Analysis of Pipeline Metal Losses in Welded Locations due to ... by the presence of large slurry of aggregates of sand stones in the pipelines. ... This investigation showed that the sand trap built insitu to sieve the sand and ...

Automated Laser Ultrasonic Testing (ALUT) of Hybrid Arc Welds for Pipeline Construction, #272

Science.gov (United States)

2009-12-22

One challenge in developing new gas reserves is the high cost of pipeline construction. Welding costs are a major component of overall construction costs. Industry continues to seek advanced pipeline welding technologies to improve productivity and s...

Evolution of weld metal microstructure in shielded metal arc welding of X70 HSLA steel with cellulosic electrodes: A case study

International Nuclear Information System (INIS)

Ghomashchi, Reza; Costin, Walter; Kurji, Rahim

2015-01-01

The microstructure of weld joint in X70 line pipe steel resulted from shielded metal arc welding with E6010 cellulosic electrodes is characterized using optical and electron microscopy. A range of ferritic morphologies have been identified ranging from polygonal inter- and intra-prior austenite grains allotriomorphic, idiomorphic ferrites to Widmanstätten, acicular and bainitic ferrites. Electron Backscatter Diffraction (EBSD) analysis using Image Quality (IQ) and Inverse Pole Figure (IPF) maps through superimposition of IQ and IPF maps and measurement of percentages of high and low angle grain boundaries was identified to assist in differentiation of acicular ferrite from Widmanstätten and bainitic ferrite morphologies. In addition two types of pearlitic structures were identified. There was no martensite detected in this weld structure. The morphology, size and chemistry of non-metallic inclusions are also discussed briefly. - Highlights: • Application of EBSD reveals orientation relationships in a range of phases for shielded metal arc welding of HSLA steel. • Nucleation sites of various ferrite morphologies identified • Formation of upper and lower bainite and their morphologies

Evolution of weld metal microstructure in shielded metal arc welding of X70 HSLA steel with cellulosic electrodes: A case study

Energy Technology Data Exchange (ETDEWEB)

Ghomashchi, Reza, E-mail: reza.ghomashchi@adelaide.edu.au; Costin, Walter; Kurji, Rahim

2015-09-15

The microstructure of weld joint in X70 line pipe steel resulted from shielded metal arc welding with E6010 cellulosic electrodes is characterized using optical and electron microscopy. A range of ferritic morphologies have been identified ranging from polygonal inter- and intra-prior austenite grains allotriomorphic, idiomorphic ferrites to Widmanstätten, acicular and bainitic ferrites. Electron Backscatter Diffraction (EBSD) analysis using Image Quality (IQ) and Inverse Pole Figure (IPF) maps through superimposition of IQ and IPF maps and measurement of percentages of high and low angle grain boundaries was identified to assist in differentiation of acicular ferrite from Widmanstätten and bainitic ferrite morphologies. In addition two types of pearlitic structures were identified. There was no martensite detected in this weld structure. The morphology, size and chemistry of non-metallic inclusions are also discussed briefly. - Highlights: • Application of EBSD reveals orientation relationships in a range of phases for shielded metal arc welding of HSLA steel. • Nucleation sites of various ferrite morphologies identified • Formation of upper and lower bainite and their morphologies.

Effect of Deformation Parameters on Microstructure and Properties During DIFT of X70HD Pipeline Steel

Science.gov (United States)

Wang, Jian; Zhu, Wei; Xiao, Hong; Zhang, Liang-liang; Qin, Hao; Yu, Yue

2018-02-01

Grain refinement is a critical approach to improve the strength of materials without damaging the toughness. The grains of deformation-induced ferrite are considerably smaller than those of proeutectoid ferrite. Grain refinement is crucial to the application of deformation-induced ferrite. The composition of ferrite and bainite or martensite is important in controlling the performance of X70HD pipeline steel, and cooling significantly influences the control of their ratio and grain size. By analyzing the static and dynamic phase-transition points using Gleeble-3800 thermal simulator, thermal simulations were performed through two-stage deformations in the austenite zone. Ferrite transformation rules were studied with thermal simulation tests under different deformation and cooling parameters based on the actual production of cumulative deformation. The influence of deformation parameters on the microstructure transformation was analyzed. Numerous fine-grain deformation-induced ferrites were obtained by regulating various parameters, including deformation temperature, strain rate, cooling rate, final cooling temperature and other parameters. Results of metallographic observation and microtensile testing revealed that the selection of appropriate parameters can refine the grains and improve the performance of the X70HD pipeline steel.

Method to reduce arc blow during DC arc welding of pipelines

Energy Technology Data Exchange (ETDEWEB)

Espina-Hernandez, J. H.; Rueda-Morales, G.L.; Caleyo, F.; Hallen, J. M. [Instituto Politecnico Nacional, Mexico, (Mexico); Lopez-Montenegro, A.; Perz-Baruch, E. [Pemex Exploracion y Produccion, Tabasco, (Mexico)

2010-07-01

Steel pipelines are huge ferromagnetic structures and can be easily subjected to arc blow during the DC arc welding process. The development of methods to avoid arc blow during pipeline DC arc welding is a major objective in the pipeline industry. This study developed a simple procedure to compensate the residual magnetic field in the groove during DC arc welding. A Gaussmeter was used to perform magnetic flux density measurements in pipelines in southern Mexico. These data were used to perform magnetic finite element simulations using FEMM. Different variables were studied such as the residual magnetic field in the groove or the position of the coil with respect to the groove. An empirical predictive equation was developed from these trials to compensate for the residual magnetic field. A new method of compensating for the residual magnetic field in the groove by selecting the number of coil turns and the position of the coil with respect to the groove was established.

Evaluation on ductile tearing properties of girth weld pipelines using SE(T) and SE(B) specimens

Energy Technology Data Exchange (ETDEWEB)

Mathias, Leonardo Luiz Siqueira; Ruggieri, Claudio [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Naval e Oceanica

2012-07-01

Predictive methodologies aimed at quantifying the impact of defects in oil and gas pipelines play a key role in safety assessment procedures of in-service facilities. Current methodologies for structural integrity assessments advocate the use of geometry dependent resistance curves so that crack-tip constraint in the test specimen closely matches the crack tip constraint for the structural component. Testing standards now under development to measure fracture resistance of pipeline steels (J and CTOD) most often employ single edge notched specimens under tension (SENT) to match a postulated defect in the structural component. This paper presents an investigation of the ductile tearing properties for a girth weld of an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves (J-R curves). Testing of the girth weld pipeline steels employed side-grooved, clamped SE(T) specimen with center-crack weld and side-grooved, three-point bending SE(B) (or SENB) specimens to determine the J-R curves. The methods were compared in terms of geometry, relative crack size and crack-tip constraint, and the results were applied to a case study, to evaluate the degree of conservativeness in defect acceptance criteria. The tests involving SE(B) specimens are usually considered conservative, however, the comparison between this two methods may point an accurate alternative for girth weld assessments, since adequate geometry is adopted to describe accurately the structure's behavior. (author)

Welding challenges constructing the alliance pipeline

International Nuclear Information System (INIS)

Gilroy-Scott, A.; Huntly, B.; Gross, B.

2001-01-01

The best Non Destructive Testing technique for Gas Metal Arc welding (GMAW) is Automated Ultrasonic Inspection because of its inherent ability to detect the planar flaws traditionally produced by GMAW operating in the short-circuiting mode in a narrow gap pipeline application. There is a tendency for GMAW flaws to be somewhat longer than those created by SMAW by the mechanised nature of the process which completes anywhere from one sixth to one half of the pipe circumference in one event. Consequently the alternative acceptance criteria of API 1104 in the USA and CSA Z662 in Canada were implemented for the ∼120,000 mechanised welds required to complete the project. Automated Ultrasonic inspection provided the ability for both the length and height of weld flaws to be determined. This is a prerequisite if alternative acceptance criteria are to be considered

Leak in spiral weld in a 16 inches gas pipeline

Energy Technology Data Exchange (ETDEWEB)

Fazzini, Pablo G; Bona, Jeremias de [GIE S.A., Mar del Plata (Argentina); Otegui, Jose L [University of Mar del Plata (Argentina)

2009-07-01

This paper discusses a failure analysis after a leak in the spiral weld of a 16 inches natural gas pipeline, in service since 1974. The leak was the result of the coalescence of two different defects, on each surface of the pipe wall, located in the center of the inner cord of the helical DSAW weld. Fractographic and metallographic studies revealed that the leak was a combination of three conditions. During fabrication of the pipe, segregation in grain boundary grouped in mid weld. During service, these segregations underwent a process of selective galvanic corrosion. One of these volumetric defects coincided with a tubular pore in the outer weld. Pigging of the pipeline in 2005 for cleaning likely contributed to the increase of the leak flow, when eliminating corrosion product plugs. Although these defects are likely to repeat, fracture mechanics shows that a defect of this type is unlikely to cause a blowout. (author)

Assessment of weld thickness loss in offshore pipelines using computed radiography and computational modeling

International Nuclear Information System (INIS)

Correa, S.C.A.; Souza, E.M.; Oliveira, D.F.; Silva, A.X.; Lopes, R.T.; Marinho, C.; Camerini, C.S.

2009-01-01

In order to guarantee the structural integrity of oil plants it is crucial to monitor the amount of weld thickness loss in offshore pipelines. However, in spite of its relevance, this parameter is very difficult to determine, due to both the large diameter of most pipes and the complexity of the multi-variable system involved. In this study, a computational modeling based on Monte Carlo MCNPX code is combined with computed radiography to estimate the weld thickness loss in large-diameter offshore pipelines. Results show that computational modeling is a powerful tool to estimate intensity variations in radiographic images generated by weld thickness variations, and it can be combined with computed radiography to assess weld thickness loss in offshore and subsea pipelines.

Polar gamma ray mode for testing weld quality natural gas pipeline

International Nuclear Information System (INIS)

Shahout, A. M.; Mahmood, A.Sh.

2005-01-01

The polar gamma-ray radiography method was studied extensively, gamma ray from Ir 192 source was used to detect weld defects in the main gas pipeline extending from Kh oms to Tripoli, gamma ray radiographic inspections were carried out according to the Astm(1) standards, and the radiographs were analyzed according to quality specifications API(2) standard-1104. The polar gamma ray mode has been applied to specimens of weld joints of pipes used in this pipeline in the reg [the kilometer 118(3)] and [the kilometer 123], and weld joints in the SLR 7 stz in the region [the kilometer 125]. The results obtained from gamma-rays have discussed and analyzed

Literature Review: Theory and Application of In-Line Inspection Technologies for Oil and Gas Pipeline Girth Weld Defection

Science.gov (United States)

Feng, Qingshan; Li, Rui; Nie, Baohua; Liu, Shucong; Zhao, Lianyu; Zhang, Hong

2016-01-01

Girth weld cracking is one of the main failure modes in oil and gas pipelines; girth weld cracking inspection has great economic and social significance for the intrinsic safety of pipelines. This paper introduces the typical girth weld defects of oil and gas pipelines and the common nondestructive testing methods, and systematically generalizes the progress in the studies on technical principles, signal analysis, defect sizing method and inspection reliability, etc., of magnetic flux leakage (MFL) inspection, liquid ultrasonic inspection, electromagnetic acoustic transducer (EMAT) inspection and remote field eddy current (RFDC) inspection for oil and gas pipeline girth weld defects. Additionally, it introduces the new technologies for composite ultrasonic, laser ultrasonic, and magnetostriction inspection, and provides reference for development and application of oil and gas pipeline girth weld defect in-line inspection technology. PMID:28036016

3D finite element modeling of in-service sleeve repair welding of gas pipelines

International Nuclear Information System (INIS)

Alian, Ahmed R.; Shazly, Mostafa; Megahed, Mohammad M.

2016-01-01

The present work investigates the influence of welding sequence and scheme on residual stresses induced during in-service sleeve repair welding of gas pipelines. For this purpose, a 3D thermo-mechanical FE analysis is conducted on an 8″-Schedule-20, API 5L-X65 steel pipe. Two welding sequences for the sleeve-pipe circumferential fillet welds are compared in the present study: sequential welding in which one side of the sleeve is welded first and then the other side is welded by the same welder, and simultaneous welding in which both sides of the sleeve are welded concurrently by two welders. Within the simultaneous welding sequence, four different welding schemes, designed to investigate the influence of the number of welders and welding directions on residual stresses, are investigated. The results show that the sequential welding sequence induces less residual stresses and distortions. Within the simultaneous welding sequence, the back-step welding scheme is found to induce the least average residual stresses as compared to other welding schemes. - Highlights: • We model in-service sleeve repair welding using 3D FE. • Model was validated through comparison with existing experimental results. • The study presents results on the effect of both welding sequence and welding scheme on the resulting residual stresses. • Sequential welding sequence generates lower residual stresses than simultaneous welding sequence. • Back-step welding scheme generates the lowest average residual stresses along the pipe circumference.

Effect of the welding process on the microstructure and microhardness of API 5L X80 steel welded joint used for oil transportation pipeline; Efeito do processo de soldagem sobre a microestrutura e a microdureza de juntas soldadas de aco API 5L X80 usado em tubulacoes para transporte de petroleo

Energy Technology Data Exchange (ETDEWEB)

Alves, R.T.P.; Albuquerque, S.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Maciel, T.M.; Almeida, D.M.; Santos, M.A.

2008-07-01

This study had as objective to evaluate the microstructure and microhardness of API 5L X80 steel welded joints, used for pipelines to transport oil and gas, using the Shield Metal Arc Welding process with pre- heating temperature of 200 deg C and 400 deg C and the AWS E8010G electrode as filler metal. For this, besides the microhardness of the welded joint, the weld metals percentiles of micro-constituents and of columnar and regenerated grains and the medium size and extension of the heat affected zone were evaluated. The percentage of acicular ferrite in weld metal ranged from 13% to 33% which generated values of microhardness from 114 HV to 309 HV. (author)

Circumferential welding of API X80 steel pipes; Soldagem circunferencial em tubos de aco da classe API X80

Energy Technology Data Exchange (ETDEWEB)

Castello Branco, J.F.; Bott, Ivani de S. [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Ciencia dos Materiais e Metalurgia]. E-mails: joaofcb@uol.com.br; bott@dcmm.puc-rio.br; Fedele, R.A. [Boehler Thyssen Welding, Sao Paulo, SP (Brazil)]. E-mail: engenharia@btwbr.com.br; Souza, Luis Felipe G. de [Centro Federal de Educacao Tecnologica Celso Suckow da Fonseca (CEFET-RJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Industrial Mecanica]. E-mail: lfelipe@cefet-rj.br

2003-07-01

The present work is a part of an extensive program for the development of API 5L Gr.X80 grade steel , produced by the well-known UOE production process, for pipeline fabrication. The current stage of this program involves the characterization and performance evaluation/qualification of girth welds produced by Shield Metal Arc Weld (SMAW) under simulated field conditions, with tubes fixed in the horizontal position. Three types of electrodes were utilized for the basic tasks; the root pass, the hot pass and fill and cap passes. The root pass was carried out with an E-6010 electrode to avoid incomplete joint penetration. The hot pass, applied over the root pass, was performed with an E-9010-G electrode. The fill and cap passes were executed with E-10018-G electrodes. The welded joints produced were evaluated according to the API 1104 specification, which requires: side bend, nick- break and tensile tests. Additionally, non-destructive tests, Charpy-V impact tests and metallographic characterization were undertaken. It was verified that this welding procedure, based on three types of electrodes, could produce welded joints in accordance to the API 1104 specification. These results ensure the applicability of the API 5L Gr. X80 steel developed in this research project for use in pipeline construction. (author)

Effect of pH Value on the Electrochemical and Stress Corrosion Cracking Behavior of X70 Pipeline Steel in the Dilute Bicarbonate Solutions

Science.gov (United States)

Cui, Z. Y.; Liu, Z. Y.; Wang, L. W.; Ma, H. C.; Du, C. W.; Li, X. G.; Wang, X.

2015-11-01

In this work, effects of pH value on the electrochemical and stress corrosion cracking (SCC) behavior of X70 pipeline steel in the dilute bicarbonate solutions were investigated using electrochemical measurements, slow strain rate tensile tests and surface analysis techniques. Decrease of the solution pH from 6.8 to 6.0 promotes the anodic dissolution and cathodic reduction simultaneously. Further decrease of the pH value mainly accelerates the cathodic reduction of X70 pipeline steel. As a result, when the solution pH decreases form 6.8 to 5.5, SCC susceptibility decreases because of the enhancement of the anodic dissolution. When the solution pH decreases from 5.5 to 4.0, SCC susceptibility increases gradually because of the acceleration of cathodic reactions.

Microstructures and mechanical properties of welded joints of novel 3Cr pipeline steel using an inhouse and two commercial welding wires

International Nuclear Information System (INIS)

Zhu, Jinyang; Xu, Lining; Chang, Wei; Hu, Lihua; Lu, Minxu

2014-01-01

Highlights: • Weldability of novel 3Cr pipeline steel was investigated using two commercial and an inhouse welding wires. • Mechanical properties were measured and microstructure characteristics were observed. • Fracture positions of tensile test just corresponded to the minimum hardness region of the joints. • The inhouse wire R01 can provide the highest cost-performance ratio. - Abstract: The welded joints of the novel 3Cr pipeline steel were fabricated via the gas tungsten arc welding (GTAW) technique using an inhouse welding wire labeled as R01 and two kinds of commercial wires (H08Cr3MoMnA and TGS-2CML). Microhardness, impact toughness and tensile properties of the joints were measured, and microstructure characteristics were observed by scanning electron microscopy (SEM). The results show that under selected welding procedure, the joints of R01 can achieve quite good mechanical properties without preheating and post weld heat treatment (PWHT). After thermal refining, elongation (15.2%) doubled and met the DNV-OS-F101 standard. For low carbon or super low carbon pipeline steels such as 3Cr steel, the revised formula with the carbon applicable coefficient (A(c)) was quite good for predicting the maximum hardness in heat affected zone (HAZ). Compared with these two selected commercial wires, the inhouse welding wire R01 can provide the highest cost-performance ratio

Strip specimen tests for pipeline materials and girth welds

Energy Technology Data Exchange (ETDEWEB)

Mohr, William C. [Edison Welding Institute (EWI), Columbus, Ohio (United States)

2009-07-01

Strip specimen testing of pipeline materials has been widely applied as a method of getting data relevant to the performance of pipelines under axial direction loading. Comparisons of strip specimen against smaller standard tests (round tensile bar, fracture toughness specimens, polished round bars) and against full-scale or large-scale testing will be explored. Data from early-generation pipe welds from the 1920's to the 1940's to the most recent materials for offshore reeled pipe will be used for examples. Strip samples can provide full thickness information to take account of varying material properties or imperfection distribution through the thickness. Strip samples can also accommodate measurement of effects of the original surface finish or weld surface shape. Strip samples have more design flexibility than standard tests, but must be designed to limit stress concentrations and effects of local bending. (author)

Weld Design, Testing, and Assessment Procedures for High Strength Pipelines

Science.gov (United States)

2011-12-20

Long-distance high-strength pipelines are increasingly being constructed for the efficient transportation of energy products. While the high-strength linepipe steels and high productivity welding processes are being applied, the procedures employed f...

75 FR 14243 - Pipeline Safety: Girth Weld Quality Issues Due to Improper Transitioning, Misalignment, and...

Science.gov (United States)

2010-03-24

... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No..., and Welding Practices of Large Diameter Line Pipe AGENCY: Pipeline and Hazardous Materials Safety... bulletin to notify owners and operators of recently constructed large diameter natural gas pipeline and...

Evaluating mechanical properties of hybrid laser arc girth welds

Energy Technology Data Exchange (ETDEWEB)

Pussegoda, L. N.; Begg, D.; Holdstock, R.; Jodoin, A. [BMT Fleet Technology Ltd Techonology, Kanata, ON, (Canada); Ligh, K.; Rondeau, D. [Appliead Thermal Sciences Inc., Sanford, ME, (United States); Hansen, E. [ESAB, Florence, SC, (United States)

2010-07-01

Hybrid laser arc welding (HLAW) is a promising new process for making girth welds on steel pipelines. This study investigated the mechanical properties of overmatched X80 and X100 pipeline steel girth welds made using the HLAW process. The testing of this process was conducted on NPS36 pipes of 10.4 mm and 14.3 mm thickness, respectively. Various weld positions were produced on X80 and X100 pipes. Laser inspection data were collected during the whole welding process. Also standard tests for girth welds, Charpy V-notch impact tests, CTOD tests, all weld metal (AWM) tension tests, were carried out. The results showed that the fracture transition temperature is higher at the 3 and 9 o'clock positions than at the 9 and 12 o'clock positions. The effect of clock position on fracture toughness is currently being explored; a modified CTOD has been developed to reduce the possibility of crack deviation.

Influence of preheating on API 5L-X80 pipeline joint welding with self shielded flux-cored wire; Influencia del precalentamiento en las propiedades de uniones soldadas de acero API 5L-X80 soldadas con alambre tubular autoprotegido

Energy Technology Data Exchange (ETDEWEB)

Cooper, R.; Silva, J. H. F.; Trevisan, R. E.

2004-07-01

The present work refers to the characterization of API 5L-X80 pipeline joints welded with self-shielded flux cored wire. This process was evaluated under preheating conditions, with an uniform and steady heat input. All joints were welded in flat position (1G), with the pipe turning and the torch still. Tube dimensions were 762 mm in external diameter and 16 mm in thickness. Welds were applied on single V-groove, with six weld beads, along with three levels of preheating temperatures (room temperature, 100 degree centigree, 160 degree centigree). These temperatures were maintained as inter pass temperature. The filler metal E71T8-K6 with mechanical properties different from parent metal was used in under matched conditions. The weld characterization is presented according to the mechanical test results of tensile strength, hardness and impact test. The mechanical tests were conducted according to API 1104, AWS and ASTM standards. API 1104 and API 51 were used as screening criteria. According to the results obtained, it was possible to remark that it is appropriate to weld API 5L-X80 steel ducts with Self-shielded Flux Cored wires, in conformance to the API standards and no preheat temperature is necessary. (Author) 22 refs.

Research and Development of Ultra-High Strength X100 Welded Pipe

Science.gov (United States)

Chuanguo, Zhang; Lei, Zheng; Ping, Hu; Bei, Zhang; Kougen, Wu; Weifeng, Huang

Ultra-high strength X100 welded pipe can be used in the construction of long distance oil and gas pipeline to improve transmission capacity and reduce operation cost. By using the way of thermo-simulation and pilot rolling, the CCT (Continuous Cooling Transformation) diagram and the relationship between ACC (Accelerated Cooling) parameters, microstructure and mechanical properties were studied for the designed X100 pipeline steel with low carbon, high manganese and niobium micro-alloyed composition in lab. The analysis of CCT diagram indicates that the suitable hardness and microstructure can be obtained in the cooling rate of 20 80°C/sec. The pilot rolling results show that the ACC cooling start temperature below Ar3 phase transformation point is beneficial to increase uniform elongation, and the cooling stop temperature of 150 350°C is helpful to obtain high strength and toughness combination. Based on the research conclusions, the X100 plate and UOE pipe with dimension in O.D.1219×W.T.14.8mm, O.D.1219×W.T.17.8mm, designed for the natural gas transmission pipeline, were trial produced. The manufactured pipe body impact absorbed energy at -10°C is over 250J. The DWTT shear area ratio at 0°C is over 85%. The transverse strength meets the X100 grade requirement, and uniform elongation is over 4%. The X100 plate and UOE pipe with dimension in O.D.711×W.T.20.0mm, O.D.711×W.T.12.5mm, designed for an offshore engineering, were also trial produced. The average impact absorbed energy of pipe body at -30°C is over 200J. The average impact absorbed energy of HAZ (Heat-affected zone) and WM (Welded Seam) at -30°C is over 100J. And the good pipe shapes were obtained

The selection of ultrasonic transducers for inspection of pipeline girth welds. Vol. 2. Evaluation of a unique creeping wave probe for examination of the cap region in pipeline girth welds

Energy Technology Data Exchange (ETDEWEB)

Fingerhut, M P; Glover, A G; Dorling, D V

1988-10-01

This work is part of a program aimed at developing an ultrasonic inspection design for the nondestructive evaluation of pipeline girth welds made by the mechanized gas metal arc (GMA) welding process for onshore and offshore pipeline construction. The feasibility of using creeping waves for examination of the cap region was investigated and, as a result, a specification for an experimental creeping wave transducer developed and a probe was designed to provide a beam oriented nearly perpendicular to expected defects in the cap region of the weld. The performance of this experimental creeping wave transducer was evaluated with respect to its ability to detect simulated and real weld defects in the cap region of mechanized GMA welds in 9.5 mm material. The probe was successful in detecting planar lack of sidewall fusion welding defects with a signal-to-noise ratio of greater than 12 dB, at depths of up to 4.2 mm from the plate surface. This indicates maximum pipe wall thicknesses of 10.9 mm may be satisfactorily examined before additional probes are required, assuming complete coverage in the root region is provided by other probes. The creeping wave probe not only performed well in the detection of real weld defects in the cap region for which it was intended, but also showed potential for detecting and discriminating some planar defects in the root region. 9 refs., 23 figs., 3 tabs.

Estimation of work capacity of welded mounting joints of pipelines of heat resisting steel

International Nuclear Information System (INIS)

Gorynin, I.V.; Ignatov, V.A.; Timofeev, B.T.; Blyumin, A.A.

1982-01-01

The analysis of a work capacity of circular welds made for the Dsub(y)850 pipeline connection with high pressure vessels of heat resisting steel of the 15Kh1NMFA type has been carried out on the base of test results with small samples and real units. Welds were performed using the manual electric arc welding without the following heat treatment. It has been shown that residual stresses in such welds do not produce an essential effect on the resistance of weld metal and heat affected zone on the formation and developments of cracks

Electrochemical Investigation of the Corrosion of Different Microstructural Phases of X65 Pipeline Steel under Saturated Carbon Dioxide Conditions

Directory of Open Access Journals (Sweden)

Yuanfeng Yang

2015-05-01

Full Text Available The aim of this research was to investigate the influence of metallurgy on the corrosion behaviour of separate weld zone (WZ and parent plate (PP regions of X65 pipeline steel in a solution of deionised water saturated with CO2, at two different temperatures (55 °C and 80 °C and at initial pH~4.0. In addition, a non-electrochemical immersion experiment was also performed at 80 °C in CO2, on a sample portion of X65 pipeline containing part of a weld section, together with adjacent heat affected zones (HAZ and parent material. Electrochemical impedance spectroscopy (EIS was used to evaluate the corrosion behaviour of the separate weld and parent plate samples. This study seeks to understand the significance of the different microstructures within the different zones of the welded X65 pipe in CO2 environments on corrosion performance; with particular attention given to the formation of surface scales; and their composition/significance. The results obtained from grazing incidence X-ray diffraction (GIXRD measurements suggest that, post immersion, the parent plate substrate is scale free, with only features arising from ferrite (α-Fe and cementite (Fe3C apparent. In contrast, at 80 °C, GIXRD from the weld zone substrate, and weld zone/heat affected zone of the non-electrochemical sample indicates the presence of siderite (FeCO3 and chukanovite (Fe2CO3(OH2 phases. Scanning Electron Microscopy (SEM on this surface confirmed the presence of characteristic discrete cube-shaped crystallites of siderite together with plate-like clusters of chukanovite.

The local heat treatment equipment and technology of the pipelines welded joints

International Nuclear Information System (INIS)

Korol'kov, P.M.

1998-01-01

The principal methods and equipment for local treatment of the pipe-lines weld joints in different industry branches is described. Recommendations about heat treatment equipment and technology application are given

46 CFR 2.75-70 - Welding procedure and performance qualifications.

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Welding procedure and performance qualifications. 2.75... for Construction Personnel § 2.75-70 Welding procedure and performance qualifications. (a) Welding... requirements for the welding of pressure piping, boilers, pressure vessels, and nonpressure vessel type tanks...

Hardness and microstructural characterization of API 5L X70 steel pipes welded by HF/ERW process; Caracterizacao microestrutural e de dureza em tubos de aco API 5L X70 soldados pelo processo HF/ERW

Energy Technology Data Exchange (ETDEWEB)

Calcada, Mauricio Vieira; Voorwald, Herman Jacobus Cornelis; Nascimento, Marcelino Pereira do [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia

2010-07-01

The materials that stand in the manufacture of steel pipes are called API, that should have, high mechanical resistance, high corrosion resistance, high fatigue resistance, good weldability, and other properties. Thus, the purpose of this project was to evaluate the microstructure and hardness of welded joints by the HF/ERW process of API 5L X70 steel pipes. The microstructural analysis was performed using a surface finish with grit sizes from 220 to 25 {mu}m e polishing with diamond paste from 9 {mu}m to 0.05 {mu}m; the revelation was made with 3% Nital attack. The Vickers hardness was performed across the welded joint by 33 points to indentation. The results were: 80.5 {+-} 3.4% of ferrite and 19.5 {+-} 3.4% of perlite for microanalysis. As for hardness, the values were: 215.69 HV10 for weld line, 218.65 HV10 for ZTA and 218.95 HV10 for base metal. (author)

Equipment for Preparing Pipeline Position Butts for Welding

Directory of Open Access Journals (Sweden)

Lobanov L.M.

2015-09-01

Full Text Available The results of developments of the Ye.O.Paton Electric Welding Institute and its specialized departments on the designing national equipment models for preparation during the assembly the edges and butt ends of pipeline position butts with the diameter from 14 up to 159 mm, repair and modernization of power engineering objects, including the power units of nuclear and heat electric stations, in chemical and machine building, at enterprises of oil-gas complex and other branches of industry are presented.

Effect of black clay soil moisture on the electrochemical behavior of API X70 pipeline steel

Science.gov (United States)

Hendi, R.; Saifi, H.; Belmokre, K.; Ouadah, M.; Smili, B.; Talhi, B.

2018-03-01

The effect of moisture content variation (20–100 wt.%) on the electrochemical behavior of API X70 pipeline steel buried in the soil of Skikda (East of Algeria) was studied using electrochemical techniques, scanning electron microscopy (SEM), X ray diffraction analysis (XRD) and weight loss measurement. The electrochemical measurements showed that the corrosion current Icorr is directly proportional to the moisture content up to 50 wt.%, beyond this content, this value becomes almost constant. The result were confirmed by electrochemical impedance spectroscopy; the capacitance of the double layer formed on the surface is the highest at 50 wt.%. A single time constant was detected by plotting the Bode diagrams. The steel surface degradation has been appreciated using the scanning electron microscopy observations. A few pitting corrosion at 20 wt.% moisture, followed by more degradation at 50 wt.% have been revealed. However, when the moisture amount exceeded 50 wt.%, the surface became entirely covered by a corrosion product. XRD analysis revealed the dominance of FeOOH and Fe3O4 phases on steel surface for a moisture content of 50 wt.%.

Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

Directory of Open Access Journals (Sweden)

Flores, J. E.

2012-10-01

Full Text Available The corrosion behavior originated by sulfate-reducing bacteria (SRB was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM and heat affected zone (HAZ, from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 °C for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM and optical microscopy (OM. H₂S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H₂S (pH minimum. It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity.

El comportamiento ante la corrosión, originada por bacterias sulfato-reductoras (SRB, fue estudiado en dos regiones de un tubo de acero soldado API X-70. Los estudios se enfocaron en el material base (BM y la zona afectada térmicamente (HAZ, en la parte interna del tubo. Las SRB fueron extraídas del petróleo y cultivadas en un medio Postgate. El comportamiento a la corrosión fue evaluado a una temperatura de 60 °C, por periodos comprendidos entre 5 y 64 días. El análisis de las curvas de polarización potenciodinámicas, obtenidas por técnicas electroquímicas, indicó la activación de la superficie para tiempos cortos. La superficie fue caracterizada estructural y morfológicamente mediante microscopia electrónica de barrido (SEM, así como mediante microscopía óptica (OM. La concentración de H₂S y el pH también fueron medidos. Los resultados mostraron un aumento importante de la corrosi

A new generation of ultra high strength steel pipelines

International Nuclear Information System (INIS)

Brozda, J.; Zeman, M.; Weglowski, M.

2008-01-01

For many years an increased demand for natural gas can be observed. Ultra high-strength pipelines with higher operating pressures and/or reduced wall thickness are a means to reduce transmission costs. Motivated by reduced investment costs (overcharge a few billion of dollars), tend towards the development of a new grade of pipeline steel with microalloying element for example Nb, that potentially lowers the total cost of long-distance gas pipelines by 5 - 15%. New long distance pipelines have budgets in excess of several billion dollars. This paper describes mechanical properties of new generation of pipelines steel with higher content of niobium and the influence the welding thermal cycles on the microstructure and brittle fracture resistance. The resistance to cold cracking has also been determined. It was found that the new steel has close properties to API X70 grade steels, but is cheaper in manufacturing and installation. The steel has been covered by the amended EN 10028-5 standard and proper modifications will also be made in other European standards. (author)

Intelligent Control of Welding Gun Pose for Pipeline Welding Robot Based on Improved Radial Basis Function Network and Expert System

Directory of Open Access Journals (Sweden)

Jingwen Tian

2013-02-01

Full Text Available Since the control system of the welding gun pose in whole-position welding is complicated and nonlinear, an intelligent control system of welding gun pose for a pipeline welding robot based on an improved radial basis function neural network (IRBFNN and expert system (ES is presented in this paper. The structure of the IRBFNN is constructed and the improved genetic algorithm is adopted to optimize the network structure. This control system makes full use of the characteristics of the IRBFNN and the ES. The ADXRS300 micro-mechanical gyro is used as the welding gun position sensor in this system. When the welding gun position is obtained, an appropriate pitch angle can be obtained through expert knowledge and the numeric reasoning capacity of the IRBFNN. ARM is used as the controller to drive the welding gun pitch angle step motor in order to adjust the pitch angle of the welding gun in real-time. The experiment results show that the intelligent control system of the welding gun pose using the IRBFNN and expert system is feasible and it enhances the welding quality. This system has wide prospects for application.

Pipeline welding with Flux Cored and Metal Cored Wire; Soldagem de dutos com processos Arame Tubular e de Alma Metalica

Energy Technology Data Exchange (ETDEWEB)

Costa, Ubirajara Pereira da [ITW Soldagem Brasil Miller-Hobart, Sao Paulo, SP (Brazil)

2003-07-01

Different welding process like SMAW, Semi-Automatic FCAW Gas-shielded and Self-shielded and Mechanized GMAW-MAG with Solid Wire are suggested to weld Transmission Pipelines. Presently, the largest extensions of Transmission Pipelines under construction, are in China like Lines West-East, Zong-Wu, Shan-Jing Fuxian and some others, totalizing about 8.000 km, and all using Semi-Automatic Self Shielded Flux Cored Arc Welding Process. Also, several papers and magazines that covers Transmission Pipelines Welding, not frequently mention Operational aspects of the process and some other variables like environment and site geography. This presentation intends to cover some of the Operational aspects of the Flux Cored Arc Welding and GMAW-Metal Cored in order to give sufficient information for Construction, Engineering, Projects e Contractors so they can evaluate these Process against the SMAW or even Mechanized Systems, considering the Operation Factor, Efficiency and Deposition Rate. We will not cover operational details of the GMAW Mechanized Systems but only suggest that be evaluated the possibility to replace the GMAW-Solid Wire by the GMAW-Metal Cored Wire. (author)

Effect of inter-critically reheating temperature on microstructure and properties of simulated inter-critically reheated coarse grained heat affected zone in X70 steel

International Nuclear Information System (INIS)

Zhu, Zhixiong; Kuzmikova, Lenka; Li, Huijun; Barbaro, Frank

2014-01-01

This study investigated the influence of the inter-critical reheating temperature on the microstructure and mechanical properties of a coarse grained heat affected zone (CGHAZ) in an API 5L grade X70 pipeline steel seam weld. A Gleeble 3500 thermo-mechanical simulator was employed to duplicate particular weld thermal cycles in order to accurately assess specific regions of the weld HAZ. Detailed microstructural analysis, including investigation of the martensite–austenite (M–A) constituent, was performed using optical microscope (OM), scanning electron microscope (SEM) and selective etching techniques. It is shown that the fracture toughness of the CGHAZ is significantly reduced following exposure to a subsequent inter-critical thermal cycle. Fracture toughness gradually improves as the inter-critical temperature is increased, but does not return to the value of the original CGHAZ due to the presence of isolated large M–A particles and coarse microstructure. Significance of M–A particles to the HAZ fracture toughness is first related to the location of particles along prior austenite grain boundaries, followed by the size of individual M–A particles

Investigation of endurance limit- and low-cycle fatigue strength of St E 47 and STE 70 in the welded and unwelded state

International Nuclear Information System (INIS)

Jaenicke, B.; Helms, R.; Florian, W.; Lipp, H.J.; Seidl, W.; Kaiser, B.

1979-01-01

To clarify clear the effect of the welding conditions and the heat treatment, alternating load tests were carried out in the endurance limit- and low-cycle-fatigue strength range on specimens of St E 47 and St E 70. Grounded basic material flat specimens cleared from their rolling skins and welded flat specimens with a butt weld of special quality were used. The welds were produced by the metal arc manual welding method with bar electrodes (low heat introduction) and with the submerged-arc welding method (high heat introduction). Part of the specimens were tempered free from stress after welding. The tests were carried out force-controlled at tension-repeated loading (S=0) and strain controlled at tension-compression alternating loading (S approx. -1). In the range of N = 5 x 10 4 ...1,5 x 10 6 cycles a small effect of the welding (special quality) for St E 47 with subsequence tempering on the endurance limit was proofed, which in comparison with the unwelded basic material (grounded surface) was characterized by broad range at nearly the same endurance limit. For St E 70, a clear decrease of the endurance limit of welded, tempered specimens (special quality) was found as compared with the basic material (grounded surface). (orig./RW) 891 RW/orig.- 892 RKD [de

Effect of Microstructure on Hydrogen Diffusion in Weld and API X52 Pipeline Steel Base Metals under Cathodic Protection

Directory of Open Access Journals (Sweden)

R. C. Souza

2017-01-01

Full Text Available The aim of this research was to evaluate the influence of microstructure on hydrogen permeation of weld and API X52 base metal under cathodic protection. The microstructures analyzed were of the API X52, as received, quenched, and annealed, and the welded zone. The test was performed in base metal (BM, quenched base metal (QBM, annealed base metal (ABM, and weld metal (WM. Hydrogen permeation flows were evaluated using electrochemical tests in a Devanathan cell. The potentiodynamic polarization curves were carried out to evaluate the corrosion resistance of each microstructure. All tests were carried out in synthetic soil solutions NS4 and NS4 + sodium thiosulfate at 25°C. The sodium thiosulfate was used to simulate sulfate reduction bacteria (SRB. Through polarization, assays established that the microstructure does not influence the corrosion resistance. The permeation tests showed that weld metal had lower hydrogen flow than base metal as received, quenched, and annealed.

Fatigue life assessment for pipeline welds by x-ray diffraction technique

International Nuclear Information System (INIS)

Lee, Sang Guk; Yoo, Keun Bong

2006-01-01

The objective of this study is to estimate the feasibility of X-ray diffraction method application for fatigue life assessment of the high-temperature pipeline steel such as main steam pipe, re-heater pipe and header etc. in power plant. In this study, X-ray diffraction tests using various types of specimen simulated low cycle fatigue damage were performed in order to analyze fatigue properties when fatigue damage conditions become various stages such as 1/4, l/2 and 3/4 of fatigue life, respectively. As a result off-ray diffraction tests for specimens simulated fatigue damages, we conformed that the variation of the full width at half maximum intensity decreased in proportion to the increase of fatigue life ratio. And also, He ratio of the full width at half maximum intensity due to fatigue damage has linear relationship with fatigue life ratio algebraically. From this relationship, it was suggested that direct expectation of the life consumption rate was feasible.

Construction of new tie-in in the Bolivia-Brazil Gas Pipeline (GASBOL) using hot tapping techniques; Derivacao do Gasoduto Bolivia-Brasil com a tecnica de hot-tapping

Energy Technology Data Exchange (ETDEWEB)

Frisoli, Caetano [TRANSPETRO - PETROBRAS Transportes, Rio de Janeiro, RJ (Brazil); Frota, Cristiane Souto; Leite Filho, Ismael Casono; Lobao Filho, Jesualdo Pereira; Saavedra, Marcelo Curto [Transportadora Brasileira Gasoduto Bolivia-Brasil, S.A., Rio de Janeiro, RJ (Brazil)

2003-07-01

To supply 2,4 MM m3/d of natural gas to Tres Lagoas thermo electric plant, it was necessary to install a new delivery point of 12'' in the 32'' trunk line of Bolivia-Brazil gas pipeline. The most efficient method for executing new delivery points and maintenance repairs in pipelines is using the 'hot-tapping' technique, because there is no need to stop flow and blow down lines. This paper shows the project, specifications, planning and a detailed job execution to support this new city-gate, using a T split sleeve welded in the pipeline, explaining all the activities. Complex and innovative aspects related to the welding and inspection processes, executed in a API 5L X70 pipe at 92 kgf/cm{sup 2}, are also reported. (author)

Equipment for welding of details and joints of plastic pipes in work shop conditions and at pipelines

International Nuclear Information System (INIS)

Doronin, V.A.

1988-01-01

A range of welding machines for operation in workshop conditions and at pipelines is presented. Set of welding equipment for mobile shop, producing prototypes, and mobile facility are developed. In 1989 they will provide the whole operation cycle of production and mounting of details and units of plastic tubes and will enable to organize the centralized production of welded and shaped details in the branch, thus excluding the shortage of these details. 8 refs.; 6 figs.; 2 tabs

Effect of Welding Parameters on Dilution and Weld Bead Geometry in Cladding

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The effect of pulsed gas metal arc welding (GMAW) variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a full factorial method, a series of experiments were carried out to know the effect of wire feed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of welding on dilution and weld bead geometry. The findings indicate that the dilution of weld metal and its dimension i.e. width, height and depth increase with the feed rate, but the contact angle of the bead decreases first and then increases. Meantime, welding speed has an opposite effect except for dilution. There is an interaction effect between welding parameters at the contact angle. The results also show forehand welding or decreasing electrode extension decrease the angle of contact. Finally,a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

Residual stress evaluation and fatigue life prediction in the welded joint by X-ray diffraction

International Nuclear Information System (INIS)

Yoo, Keun Bong; Kim, Jae Hoon

2009-01-01

In the fossil power plant, the reliability of the components which consist of the many welded parts depends on the quality of welding. The residual stress is occurred by the heat flux of high temperature during weld process. This decreases the mechanical properties as the strength of fatigue and fracture or occurs the stress corrosion cracking and fatigue fracture. The residual stress of the welded part in the recently constructed power plants has been the cause of a variety of accidents. The objective of this study is measurement of the residual stress by X-ray diffraction method and to estimate the feasibility of this application for fatigue life assessment of the high-temperature pipeline. The materials used for the study is P92 steel for the use of high temperature pipe on super critical condition. The test results were analyzed by the distributed characteristics of residual stresses and the Full Width at Half Maximum intensity (FWHM) in x-ray diffraction intensity curve. Also, X-ray diffraction tests using specimens simulated low cycle fatigue damage were performed in order to analyze fatigue properties when fatigue damage conditions become various stages. As a result of X-ray diffraction tests for specimens simulated fatigue damages, we conformed that the ratio of the FWHM due to fatigue damage has linear relationship with fatigue life ratio algebraically. From this relationships, it was suggested that direct expectation of the life consumption rate was feasible.

Effect of using the double layer technique on the microstructure, microhardness and residual stress of welded ASTM A516 GR70 structural steel

International Nuclear Information System (INIS)

Oliveira, George Luiz Gomes de; Miranda, Helio Cordeiro de

2010-01-01

The aim of this work is to evaluate the effect of using the double layer technique on the microstructure, microhardness and residual stresses of welded ASTM A516 Gr70 structural steel. Samples were welded with the same welding parameters and two types of chamfers, while the samples welded using the double layer technique underwent a buttering process on their chamfer face. Residual stress measurement was accomplished through x-ray diffraction, using a mini diffractometer for measurement in field. Metallographic analysis was accomplished in the transverse section of the welded joint, using optic microscopy and scanning electron microscopy. The double layer technique showed that can be used in the welding of ASTM A516 Gr70 steel, because, besides promote a refinement and a drawing back of the CG-HAZ, it increased compressive residual stress in the whole surface of the analyzed samples.(author)

49 CFR 192.225 - Welding procedures.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Welding procedures. 192.225 Section 192.225... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.225 Welding procedures. (a) Welding must be performed by a qualified welder in accordance with welding procedures...

Joining of Materials with Diferent Properties Through Submerged Arc Welding Process and Destructive and Non-Destructive Testing of the Joints

Directory of Open Access Journals (Sweden)

Yakup Kaya

2013-01-01

Full Text Available In this study, X60, X65 and X70 steels used in petroleum and natural gas pipeline were joined with Submerged Arc Welding by using different type of welding fluxes (LN761 and P223 and wires (S1 and S2Mo. Initially, visual and radiographic inspection techniques were subjected to welded joints for determining surface and subsurface defects. After that, spectral analyses were carried out in order to determine the compositions of wire-flux-base metal on the joints. Impact toughness test were performed for determining toughness properties the joints. Furthermore, hardness and microstructure studies were also carried out on the samples. As a result of the visual and radiographic inspection on the welded samples, there were no weld defects on joints were observed. It was clearly understood that carbon ratio in the compositions of weld metal higher than base metal but lower than filler metal in terms of spectral analyses results. According to impact toughness test results, the joints obtained by using S2Mo welding wire and P223 welding flux had better impact toughness value than the joints obtained by S1 welding wire and LN 761 welding flux. With respect to hardness test, the highest hardness values were measured on weld metal. When the microstructure images were examined, it is clearly understood that similar images for all the joints were shown adjacent zones to weld metals heat affected zones and welding boundary, due to heat input constant.

Correction factors for safe performance of API X65 pipeline steel

International Nuclear Information System (INIS)

Hashemi, Sayyed H.

2009-01-01

Prediction of required Charpy energy for fracture arrest is vital for safe performance of gas transportation pipelines. This is commonly estimated through failure models calibrated in the past on fracture data from combined Charpy tests and full-thickness burst experiments. Unfortunately, such pipeline failure models are unable to correctly predict the minimum arrest toughness of thermo-mechanical controlled rolled (TMCR) steels. To refine the existing failure models, different empirical adjustments have been proposed in recent years. In this paper, similar correction factors were derived from fracture information of instrumented Charpy impact tests on API X65 steel. The contribution of different fracture mechanisms of impact test specimens was determined through energy partitioning analysis. Parts of the energy contribution were correlated then to the source of uncertainty observed in similar experiments. The applied technique was similar to that of previous studies on X70 and X100 steels, and proved to be encouraging in giving consistent results compared to available test data.

The effect of processing parameters on the dynamic recrystallisation behaviour of API-X70 pipeline steel

International Nuclear Information System (INIS)

Al Shahrani, Abdullah; Yazdipour, Nima; Dehghan-Manshadi, Ali; Gazder, Azdiar A.; Cayron, Cyril; Pereloma, Elena V.

2013-01-01

The effect of deformation temperature and strain rate on the dynamic recrystallisation (DRX) behaviour of X70 pipeline steel was investigated. DRX parameters such as the critical and peak stresses and strains as well as the deformation activation energy were determined in the temperature range between 925 °C and 1125 °C for strain rates of 0.1, 1 and 5 s −1 . The relationship between the peak stresses and strains with the Zener–Hollomon parameter was determined. The dynamically recrystallised volume fraction was computed as a function of the different temperatures and strain rates. The APRGE software was applied for the first time on electron back-scattering diffraction data of dynamically recrystallised microstructures in order to reconstruct the prior austenite from the as-quenched martensite phase. The dynamically recrystallised flow stress curves and microstructure were also predicted using cellular automata modelling. The results show an earlier onset of DRX with a decrease in strain rate or an increase in deformation temperature. The dynamically recrystallised grain size is also found to decrease with an increase in strain rate and a lowering of deformation temperature

49 CFR 192.235 - Preparation for welding.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Preparation for welding. 192.235 Section 192.235... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.235 Preparation for welding. Before beginning any welding, the welding surfaces must be clean and free of any material that...

X-ray radiography of Ti6Al4V welded by plasma tungsten arc (PTA) welding

Energy Technology Data Exchange (ETDEWEB)

Dikbas, Halil; Caligulu, Ugur; Taskin, Mustafa; Turkmen, Mustafa [Firat Univ., Elazig (Turkey). Metallurgy Dept.

2013-03-01

In this study, X-ray radiographic tests of Ti6Al4V alloys welded by plasma tungsten arc welding (PTA) were investigated. PTA welding experiments were carried out under argon shielding gas atmosphere, at 1400-1600 W and 1800 W welding powers as well as 1 m/min, 0.75 m/min, and 0.50 m/min welding speeds. After this process, radiography of the welded joints was performed by X-ray diffraction. The result of the radiographic tests indicated that by increasing welding power the widths of deep penetration increased in all specimens. On the contrary, increasing welding speeds decreases the widths deep penetration. The best properties of Ti6Al4V joints were observed for specimens welded at 1800 W welding power and at 0.50 m/min welding speed. (orig.)

Residual stress characterization of welds using x-ray diffraction techniques

International Nuclear Information System (INIS)

Pineault, J.A.; Brauss, M.E.

1996-01-01

Neglect of residual stresses created during processes lead to stress corrosion cracking, distortion, fatigue cracking, premature failures in components, and instances of over design. Automated residual stress mapping and truly portable equipment have now made the characterization of residual stresses using x-ray diffraction (XRI) practical. The nondestructive nature of the x-ray diffraction technique has made the tile residual stress characterization of welds a useful tool for process optimization and failure analysis, particularly since components can be measured before and after welding and post welding processes. This paper illustrates the importance of residual stress characterization in welds and presents examples where x-ray diffraction techniques were applied in the characterization of various kinds of welds. arc welds, TIG welds, resistance welds, laser welds and electron beam welds. Numerous techniques are available to help manage potentially harmfull residual stresses created during the welding process thus, the effects of a few example post weld processes such as grinding, heat treating and shot peening are also addressed

STUDY OF ARC IMPULSE FREQUENCY EFFECT ON THE STRUCTURE AND PROPERTIES OF WELDED CONNECTION ELEMENTS IN ALUMINIUM PIPELINE SYSTEMS, MADE WITH MASTERTIG 3500

Directory of Open Access Journals (Sweden)

Mr. Pavel V. Bakhmatov

2016-06-01

Full Text Available Summary . The article focuses on the arc impulse frequency effect on the structure and properties of welded connections in aluminum pipeline systems hand-operated with argon-arc welding nonconsumable rod on MasterTig3500. It was revealed that the frequency of the welding current impulses plays an important role in the forming of the welded connection. The authors determined the optimal value of the welding current frequency significantly accelerating the welding process to ensure consistent quality of the weld. The authors detailed some features of cleaning assembly parts with a wire brush prior to welding process.

An automatic approach for nondestructive radiographic inspection of pipeline weld joint; Uma abordagem automatica aplicada a inspecao radiografica nao-destrutiva de soldas em tubulacoes

Energy Technology Data Exchange (ETDEWEB)

Felisberto, Marcelo K.; Schneider, Guilherme A.; Centeno, Tania M.; Arruda, Lucia V.R. de [Centro Federal de Educacao Tecnologica do Parana, Curitiba, PR (Brazil). CPGEI - Programa de Pos-graduacao em Engenharia Eletrica e Informatica Industrial

2005-07-01

The current work contributes to the research in the area of pipelines non-destructive testing by presenting new methodologies for the automatic analysis of welds radiographs. Object recognition techniques based on genetic algorithms were used for the automatic weld bead detection. In addiction, an image digital filter was also tested in the weld bead images and, as a result, supposed defects are highlighted, making them easier to be detected. These methodologies were tested for 120 digital radiographs from carbon steel pipeline welded joints. These images were acquired by a storage phosphor system, using double-wall radiographic exposing technique with single-wall radiographic viewing, according to the ASME V code. As a result, even human vision hard-perceptible defects are automatically highlighted and extracted from the whole image to be separately analyzed. (author)

49 CFR 195.224 - Welding: Weather.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Welding: Weather. 195.224 Section 195.224 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Construction § 195.224 Welding: Weather. Welding must be protected from weather conditions that...

Incidental electric heating of pipelines

Energy Technology Data Exchange (ETDEWEB)

Sonninskii, A V; Sirotin, A M; Vasiliev, Y N

1981-04-01

VNIIgaz has improved the conventional Japanese SECT pipeline-heating system, which uses a small steel tube that contains an insulated heater/conductor and is welded to the top of the pipeline. The improved version has two insulated electric heaters - one on the top and the other on the bottom of the pipeline - located inside steel angle irons that are welded to the pipeline. A comparison of experimental results from heating a 200-ft pipeline with both systems at currents of up to 470 A clearly demonstrated the better heating efficiency of the VNIIgaz unit. The improved SECT system would be suitable for various types of pipelines, including gas lines, in the USSR's far north regions.

Welding with high power fiber lasers - A preliminary study

International Nuclear Information System (INIS)

Quintino, L.; Costa, A.; Miranda, R.; Yapp, D.; Kumar, V.; Kong, C.J.

2007-01-01

The new generation of high power fiber lasers presents several benefits for industrial purposes, namely high power with low beam divergence, flexible beam delivery, low maintenance costs, high efficiency and compact size. This paper presents a brief review of the development of high power lasers, and presents initial data on welding of API 5L: X100 pipeline steel with an 8 kW fiber laser. Weld bead geometry was evaluated and transition between conduction and deep penetration welding modes was investigated

The mutual effects of hydrogen and microstructure on hardness and impact energy of SMA welds in X65 steel

Energy Technology Data Exchange (ETDEWEB)

Latifi, V. Amin; Miresmaeili, Reza, E-mail: miresmaeili@modares.ac.ir; Abdollah-Zadeh, Amir

2017-01-02

Micro-alloy steels are broadly used in gas and petroleum transportation industries. However, application of these steels in pipelines is challenged by hydrogen embrittlement due to presence of hydrogen sulfide in the medium. The present work deals with the interaction of hydrogen with plasticity of X65 steel. Two weld joints produced by common E7010-G and E7018 electrodes via shielded metal arc welding (SMAW) method were also investigated. It was revealed in microhardness test that direct charge of hydrogen to the surface did not lead to meaningful variations due to lamination as well as surface and sub-surface porosities. In fact, the effect of hydrogen on material plasticity was influenced by lamination and porosities. On the other hand, indirect charge on the tested surface led to increase in hardness by 12%, 9% and 6% in base metal as well as in weld metals obtained from E7010-G and E7018 electrodes, respectively. Therefore, hydrogen atoms affected plasticity of X65 steel more harshly than that of weld metals; thus, the base metal is more sensitive to hydrogen embrittlement. Due to high strain rate, impact test does not provide sufficient time for hydrogen diffusion through notch during the test. No observation of any variations in impact energies of charged samples may hence be explained by uniform hydrogen concentration throughout the samples. The base steel was seen to be much more sensitive to hydrogen defects rather than weld metals of both electrodes due to possessing pearlite/ferrite interfaces. According to hydrogen concentration studies, E710-G weld metal had more hydrogen diffusivity than X65 steel and E7018 weld metal by four time and 25%, respectively. This was due to acicular ferritic microstructure of E710-G weld metal and its dislocation tangles that provided many reversible traps for hydrogen.

Effect of Thermomechanical Processing and Crystallographic Orientation on the Corrosion Behavior of API 5L X70 Pipeline Steel

Science.gov (United States)

Ohaeri, Enyinnaya; Omale, Joseph; Eduok, Ubong; Szpunar, Jerzy

2018-04-01

This work presents the electrochemical response of X70 pipeline steel substrates thermomechanically processed at different conditions. The WE sample was hot rolled at a temperature range of 850 °C to 805 °C and cooled at a rate of 42.75 °C/s. Another sample WD was hot rolled from 880 °C to 815 °C and cooled at a faster rate of 51.5 °C/s. Corrosion tests were conducted electrochemically by potentiodynamic polarization in hydrogen-charged and non-hydrogen-charged environments. A lower corrosion rate was measured with hydrogen charging due to the rapid formation of corrosion product film on pipeline substrate, but WE specimen emerged as the most susceptible to corrosion with and without hydrogen charging. Variations in thermomechanical rolling conditions influenced grain orientation, protective film properties, corrosion, and cracking behavior on both specimens. Cracks were seen in both specimens after hydrogen charging, but specimen WE experienced a more intense deterioration of protective corrosion product film and subsequent cracking. A large part of specimen WD retained its protective corrosion product film after the polarization test, and sites where spalling occurred resulted in pitting with less cracking. Despite weak crystallographic texture noticed in both specimens, WD showed a higher intensity of corrosion-resistant 111||ND-oriented grains, while WE showed a more random distribution of 111||ND-, 011||ND-, and 001||ND-oriented grains with a lower intensity.

Effect of Thermomechanical Processing and Crystallographic Orientation on the Corrosion Behavior of API 5L X70 Pipeline Steel

Science.gov (United States)

Ohaeri, Enyinnaya; Omale, Joseph; Eduok, Ubong; Szpunar, Jerzy

2018-06-01

This work presents the electrochemical response of X70 pipeline steel substrates thermomechanically processed at different conditions. The WE sample was hot rolled at a temperature range of 850 °C to 805 °C and cooled at a rate of 42.75 °C/s. Another sample WD was hot rolled from 880 °C to 815 °C and cooled at a faster rate of 51.5 °C/s. Corrosion tests were conducted electrochemically by potentiodynamic polarization in hydrogen-charged and non-hydrogen-charged environments. A lower corrosion rate was measured with hydrogen charging due to the rapid formation of corrosion product film on pipeline substrate, but WE specimen emerged as the most susceptible to corrosion with and without hydrogen charging. Variations in thermomechanical rolling conditions influenced grain orientation, protective film properties, corrosion, and cracking behavior on both specimens. Cracks were seen in both specimens after hydrogen charging, but specimen WE experienced a more intense deterioration of protective corrosion product film and subsequent cracking. A large part of specimen WD retained its protective corrosion product film after the polarization test, and sites where spalling occurred resulted in pitting with less cracking. Despite weak crystallographic texture noticed in both specimens, WD showed a higher intensity of corrosion-resistant 111|| ND-oriented grains, while WE showed a more random distribution of 111|| ND-, 011|| ND-, and 001|| ND-oriented grains with a lower intensity.

Methodological development and characterization of welded joints in Poly (vinylidene fluoride) (PVDF)

International Nuclear Information System (INIS)

Cedrola, S.M.L.; Costa, M.F. da; Pasqualino, I.P.

2010-01-01

Pipelines are of great concern in the transport sector of oil and gas industries, mainly due to the natural internal aging process caused by contact with the different transported fluids. Installation of polymeric pipes called liners is a good option for rehabilitation of long segments of deteriorated pipelines. Among the potential materials for such application is Poly (vinylidene fluoride) (PVDF). Meanwhile the installation process cannot be carried out in one single step and the polymeric pipe must be cut in sections that are welded during the installation process. In this research welding methodology was studied aiming to optimize welding conditions and the mechanical properties of the joined materials. The first step was processing the PVDF via compression molding on different conditions. Then, the sample was cut and butt-welded. Welding parameters such as, time control, temperature and contact pressure were studied. Afterwards, the stress-strain properties of the welded material was evaluated and physical characterization was carried by x-ray diffraction (DRX). (author)

Inclusion Characteristics and Acicular Ferrite Nucleation in Ti-Containing Weld Metals of X80 Pipeline Steel

Science.gov (United States)

Wang, Bingxin; Liu, Xianghua; Wang, Guodong

2018-06-01

X80 steel weld metals with Ti contents of 0.003 to 0.13 pct were prepared by the single-pass submerged-arc welding process. The effects of Ti content in weld metals on the constituent phases of inclusions and chemical compositions of the constituent phases, as well as the potency of acicular ferrite (AF) nucleation on the inclusions were investigated. Moreover, the crystallographic orientation relationship between the AF and inclusion was examined. The results show that with an increase in Ti content, the primary constituent phases of the inclusions change from the (Mn-Al-Si-O) compound to a mixture of spinel and pseudobrookite solid solutions, and eventually to pseudobrookite. The spinel solid solution is characterized by the MnTi2O4 constituent. Compared to pseudobrookite, spinel has a lower Ti concentration, but a significantly higher Mn content. In the case of the presence of a considerable amount of spinel, the Mn element is enriched strongly in the inclusions, resulting in the development of a Mn-depleted zone (MDZ) in the matrix around the inclusions, which enhances the driving force for AF formation. AF shows the Baker-Nutting orientation relationship with MnTi2O4. The formation of MDZ and the presence of the Baker-Nutting orientation relationship promote the ability of inclusions to nucleate the intragranular AF.

Computer software to assess weld thickness loss in offshore pipelines: PEDS

Energy Technology Data Exchange (ETDEWEB)

Germano, Andre Luiz Silva; Correa, Samanda Cristine Arruda [Centro Universitario Estadual da Zona Oeste (CCMAT/UEZO), Rio de Janeiro, RJ (Brazil)], e-mail: scorrea@nuclear.ufrj.br; Souza, Edmilson Monteiro de; Silva, Ademir Xavier da; Lopes, Ricardo Tadeu [Programa de Engenharia Nuclear, COPPE, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)], e-mails: emonteiro@nuclear.ufrj.br, ademir@nuclear.ufrj.br, ricardo@lin.ufrj.br

2010-07-01

The purpose of this work is to present an initial vision about a computer software named PEDS to assess weld thickness loss in offshore pipelines through digital radiography. This software calculates the thickness loss through a data bank obtained using computational modeling based on Monte Carlo MCNPX code. In order to give users more flexibility, the computer software was written in Java, which allows it to run on Linux, Mac OSX and Windows. Furthermore, tools are provided to image display, select and analyze specific areas of the image (measure average, area of selection) and generate profile plots. Applications of this software in the offshore area are presented. (author)

49 CFR 192.241 - Inspection and test of welds.

Science.gov (United States)

2010-10-01

... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.241 Inspection and test of welds. (a) Visual inspection of welding must be conducted by an individual qualified by appropriate training and experience to ensure that: (1) The welding is performed in accordance...

Industry standards catch up with in-service welding

Energy Technology Data Exchange (ETDEWEB)

Bruce, W.A.

1999-11-01

Welding onto a pipeline after it has been put into service, a practice commonly referred to as hot tap welding, is frequently required for several reasons. Repair sleeves are installed to reinforce areas of corrosion or mechanical damage, and branch connections are made for system modifications. There are often significant economic incentives to perform this welding without removing the system from service. Operations are maintained during welding and the pipe's contents are not vented into the atmosphere. Due to technological advances in in-service welding, industry needed an update to standards and recommended practices. This year, the American Petroleum Institute (API) hopes to meet that need. The 19th edition of API Standard 1104--Welding of Pipelines and Related Facilities, includes a new appendix that pertains to in-service welding. Appendix B, In-Service Welding, is intended to eventually replace API Recommended Practice 1107--Pipeline Maintenance Welding Practices. API 1107, which was introduced in 1966 and updated in 1987 and 1991, is intended to provide recommended practices for pipeline maintenance welding. The current third edition approached its mandatory five-year review in 1996 by the API-AGA Joint Committee on Oil and Gas Pipeline Field Welding Practices, which also maintains API 1104. The committee saw 11078 needed to reflect the updates that had been made to 1104 as well as the technological advances for in-service welding. To alleviate redundancy between the two documents, and to alleviate lag time between updates, the committee approved a proposal to update and incorporate requirements of API 1107 into an appendix of API 1104. In the meantime, the third edition of API 1107 was reapproved for another five-year review cycle.

Relationship between Pipeline Wall Thickness (Gr. X60) and Water Depth towards Avoiding Failure during Installation

Science.gov (United States)

Razak, K. Abdul; Othman, M. I. H.; Mat Yusuf, S.; Fuad, M. F. I. Ahmad; yahaya, Effah

2018-05-01

Oil and gas today being developed at different water depth characterized as shallow, deep and ultra-deep waters. Among the major components involved during the offshore installation is pipelines. Pipelines are a transportation method of material through a pipe. In oil and gas industry, pipeline come from a bunch of line pipe that welded together to become a long pipeline and can be divided into two which is gas pipeline and oil pipeline. In order to perform pipeline installation, we need pipe laying barge or pipe laying vessel. However, pipe laying vessel can be divided into two types: S-lay vessel and J-lay vessel. The function of pipe lay vessel is not only to perform pipeline installation. It also performed installation of umbilical or electrical cables. In the simple words, pipe lay vessel is performing the installation of subsea in all the connecting infrastructures. Besides that, the installation processes of pipelines require special focus to make the installation succeed. For instance, the heavy pipelines may exceed the lay vessel’s tension capacities in certain kind of water depth. Pipeline have their own characteristic and we can group it or differentiate it by certain parameters such as grade of material, type of material, size of diameter, size of wall thickness and the strength. For instances, wall thickness parameter studies indicate that if use the higher steel grade of the pipelines will have a significant contribution in pipeline wall thickness reduction. When running the process of pipe lay, water depth is the most critical thing that we need to monitor and concern about because of course we cannot control the water depth but we can control the characteristic of the pipe like apply line pipe that have wall thickness suitable with current water depth in order to avoid failure during the installation. This research will analyse whether the pipeline parameter meet the requirements limit and minimum yield stress. It will overlook to simulate pipe

Automatic weld joint X-ray inspection

International Nuclear Information System (INIS)

Richter, H.U.; Linke, D.; Siems, K.D.; Kruse, H.; Schuetze, E.

1990-01-01

A gantry mounted robotic x-ray inspection unit has been developed for the series testing of small and medium sized welded components (pipe bends and nozzles). The unit features computer controlled positioning of the x-ray tube and x-ray image amplifier. Image quality classes 2 and even 1 could be achieved without difficulty. (author)

Corrosion study of API 5L x-series pipeline steels in 3.5% NaCl solution under varying conditions

International Nuclear Information System (INIS)

Shahid, M.; Qureshi, M.I.; Farooq, M.U.; Khan, M.I.

2003-01-01

Pipelines provide convenient and efficient means for mass transportation of variety of fluids, such as oil and gas, over varying distances. In the last two decades or so, pipeline designers focused mainly on the usage of larger sizes and higher operating pressures for achieving higher transportation efficiency. This has been accomplished through the provision of steels with progressive increase in yield strength coupled with good weldability and sufficient toughness to restrict crack propagation. In addition to higher strength and toughness, developing pipeline technologies have required improved resistance to corrosion, which has been tried with specific alloy additions and special control over non-metallic inclusions. Corrosion investigations were carried out on various grades of pipeline steels (API 5L X-46, X-52, X-56, X-60 and X- 70) under varying environmental conditions. This paper describes the results pertaining to corrosion behavior of the steels in 3.5% NaCl solutions in stagnant, turbulent and deaerated conditions. It was found that all grades corrode in this solution and their corrosion potentials and corrosion currents are in close vicinity of each other. Turbulent solutions, however, have shown an increase in corrosion rates whereas deaeration has revealed a relative decrease in aggressivity of the electrolyte. (author)

A study on the development of repair procedure for gas pipelines

Energy Technology Data Exchange (ETDEWEB)

Kim, W S; Kim, Y P; Baek, J H [R and D Center, Korea Gas Corporation, Ansan (Korea)

1999-06-01

In the buried natural gas pipelines, many defects may occur by construction faults, corrosion, third-party interference and ground movement. When a segment of a pipeline is found to be defective, one of the repair methods is to remove its contents and cut out the defective segment after shutting down the pipeline. However, the cost is extremely high in terms of venting and disrupting the gas supply. Therefore, most pipeline companies have developed in-service repair methods without removing the line from service. In general, in order to avoid removing the line from service, direct deposition of weld metal, full-encirclement sleeve, patches, stopple fittings, half-sole and branch connections are required. There are three important concerns in the sleeve-repair welding like other methods of in-service repair-welding. The first concern is the possibility of burn-through which is due to the localized heating and loss of meterial strength on the inner surface of pipe during the welding process. The pipe wall may burst under internal pressure if the loss in strength is too great. The second concern is the high cooling rates by the flowing gas which quickly removes heat from the pipe wall, resulting in accelerated cooling of the weld. Such rapid cooling rates promote the formation of hard heat affected zone microstructure making these welds susceptible to hydrogen cracking. The third concern is for the load carrying ability, such as tensile strength, fracture toughness and fatigue strength. This study was taken to investigate the effect of in-service welding conditions and assess the mechanical properties for the direct deposition welding and sleeve-repair welding of in-service gas pipelines and develope the welding procedure specification for in-service pipeline repair. 81 figs., 40 tabs.

Residual stress evaluation by X-Ray diffraction and hole-drilling in an API 5L X70 steel pipe bent by hot induction

International Nuclear Information System (INIS)

Ceglias, Rodrigo Braga; Alves, Juciane Maria; Botelho, Ramon Alves; Baeta Junior, Eustaquio de Souza; Santos, Igor Cuzzuol dos; Moraes, Nicki Robbers Darciano Cajueiro de; Oliveira, Rebeca Vieira de; Diniz, Saulo Brinco; Brandao, Luiz Paulo

2016-01-01

The API 5L X70 steel is used in high-pressure gas transmission pipelines. Because of this, knowledge of presence of residual stress and their magnitude is important to assess the material integrity in service. For the pipeline manufacturing, tubes need to be curved which is often made using the hot induction bending process. This process can introduce different residual stress depending of tube position. For this research, in order to evaluate the residual stress, was used an API 5L X70 tube that was previously curved by hot induction process. Samples were taken from the extrados, intrados, neutral line and straight section of the curved tube. Residual stresses were studied by two conventional methods: X-Ray Diffraction (XRD) and Hole-Drilling, which are destructive and non-destructive methods, respectively, in order to assess their qualitative responses. Each of these methods presents particular methodologies in sample preparation and material analysis, but also they differ in factors such time consumption and cost of the analysis. The qualitative responses obtained by the two different methods were comparable and satisfactory and pointed out the existence of a compressive residual stress state in steel pipe. (author)

Residual stress evaluation by X-Ray diffraction and hole-drilling in an API 5L X70 steel pipe bent by hot induction

Energy Technology Data Exchange (ETDEWEB)

Ceglias, Rodrigo Braga; Alves, Juciane Maria; Botelho, Ramon Alves; Baeta Junior, Eustaquio de Souza; Santos, Igor Cuzzuol dos; Moraes, Nicki Robbers Darciano Cajueiro de; Oliveira, Rebeca Vieira de; Diniz, Saulo Brinco; Brandao, Luiz Paulo, E-mail: brandao@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Mecanica e de Materiais

2016-09-15

The API 5L X70 steel is used in high-pressure gas transmission pipelines. Because of this, knowledge of presence of residual stress and their magnitude is important to assess the material integrity in service. For the pipeline manufacturing, tubes need to be curved which is often made using the hot induction bending process. This process can introduce different residual stress depending of tube position. For this research, in order to evaluate the residual stress, was used an API 5L X70 tube that was previously curved by hot induction process. Samples were taken from the extrados, intrados, neutral line and straight section of the curved tube. Residual stresses were studied by two conventional methods: X-Ray Diffraction (XRD) and Hole-Drilling, which are destructive and non-destructive methods, respectively, in order to assess their qualitative responses. Each of these methods presents particular methodologies in sample preparation and material analysis, but also they differ in factors such time consumption and cost of the analysis. The qualitative responses obtained by the two different methods were comparable and satisfactory and pointed out the existence of a compressive residual stress state in steel pipe. (author)

Health monitoring of pipeline girth weld using empirical mode decomposition

Science.gov (United States)

Rezaei, Davood; Taheri, Farid

2010-05-01

In the present paper the Hilbert-Huang transform (HHT), as a time-series analysis technique, has been combined with a local diagnostic approach in an effort to identify flaws in pipeline girth welds. This method is based on monitoring the free vibration signals of the pipe at its healthy and flawed states, and processing the signals through the HHT and its associated signal decomposition technique, known as empirical mode decomposition (EMD). The EMD method decomposes the vibration signals into a collection of intrinsic mode functions (IMFs). The deviations in structural integrity, measured from a healthy-state baseline, are subsequently evaluated by two damage sensitive parameters. The first is a damage index, referred to as the EM-EDI, which is established based on an energy comparison of the first or second IMF of the vibration signals, before and after occurrence of damage. The second parameter is the evaluation of the lag in instantaneous phase, a quantity derived from the HHT. In the developed methodologies, the pipe's free vibration is monitored by piezoceramic sensors and a laser Doppler vibrometer. The effectiveness of the proposed techniques is demonstrated through a set of numerical and experimental studies on a steel pipe with a mid-span girth weld, for both pressurized and nonpressurized conditions. To simulate a crack, a narrow notch is cut on one side of the girth weld. Several damage scenarios, including notches of different depths and at various locations on the pipe, are investigated. Results from both numerical and experimental studies reveal that in all damage cases the sensor located at the notch vicinity could successfully detect the notch and qualitatively predict its severity. The effect of internal pressure on the damage identification method is also monitored. Overall, the results are encouraging and promise the effectiveness of the proposed approaches as inexpensive systems for structural health monitoring purposes.

High power X-ray welding of metal-matrix composites

Energy Technology Data Exchange (ETDEWEB)

Rosenberg, Richard A.; Goeppner, George A.; Noonan, John R.; Farrell, William J.; Ma, Qing

1997-12-01

A method for joining metal-matrix composites (MMCs) by using high power x-rays as a volumetric heat source is provided. The method involves directing an x-ray to the weld line between two adjacent MMCs materials to create an irradiated region or melt zone. The x-rays have a power density greater than about 10{sup 4} watts/cm{sup 2} and provide the volumetric heat required to join the MMC materials. Importantly, the reinforcing material of the metal-matrix composites remains uniformly distributed in the melt zone, and the strength of the MMCs are not diminished. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys.

Influence of crystallographic texture in X70 pipeline steels on toughness anisotropy and delamination

Science.gov (United States)

Al-Jabr, Haytham M.

The effects of microstructure and crystallographic texture in four commercially-produced API X70 pipeline steels and their relation to planar anisotropy of toughness and delamination were evaluated. The experimental steels were processed through either a hot strip mill, a Steckel mill, or a compact strip mill. Different processing routes were selected to obtain plates with potential variations in the microstructure and anisotropic characteristics. Tensile and Charpy impact testing were used to evaluate the mechanical properties in three orientations: longitudinal (L), transverse (T) and diagonal (D) with respect to the rolling direction to evaluate mechanical property anisotropy. The yield and tensile strengths were higher in the T orientation and toughness was lower in the D orientation for all plates. Delamination was observed in some of the ductile fracture surfaces of the impact samples. To further study the splitting behavior and effects on impact toughness, a modified impact test (MCVN) specimen with side grooves was designed to intensify induced stresses parallel to the notch root and thus facilitate evaluation of delamination. Scanning electron microscopy combined with electron backscattered diffraction (EBSD) were used to evaluate the grain size, microstructural constituents, and crystallographic texture to determine the factors leading to delamination and the anisotropy in toughness. The ferrite grain size is mainly responsible for the differences in DBTTs between the L and T orientations. The higher DBTT in the D orientation observed in pipeline steels is attributed to crystallographic texture. The higher DBTT in the D direction is due to the higher volume fraction of grains having their {100} planes parallel or close to the primary fracture plane for the D orientation. An equation based on a new "brittleness parameter," based on an assessment of grain orientations based on EBSD data, was developed to predict the changes in DBTTs with respect to sample

Effect of multiple repairs in girth welds of pipelines on the mechanical properties

International Nuclear Information System (INIS)

Vega, O.E.; Hallen, J.M.; Villagomez, A.; Contreras, A.

2008-01-01

This work presents the results of multiple weld repairs in the same area in seamless API X-52 microalloyed steel pipe. Four conditions of shielded metal arc welding repairs and one as-welded specimen of the girth weld were characterized to determine changes in the microstructure, grain size in the heat affected zone, and to evaluate their effect on the mechanical properties of the weld joints. The mechanical properties by means of tension tests, Charpy-V impact resistance and Vickers hardness of the welds were analyzed. The results indicate that significant changes are not generated in the microstructural constituents of the heat affected zone. Grain growth in the heat affected zone at the specimen mid-thickness with the number of repairs was observed. Tensile strength of the weld joints meets the requirement of the API 1104 standard even after the fourth weld repair. Significant reduction in Charpy-V impact resistance with the number of weld repairs was found when the notch location was in the intersection of the fusion line with the specimen mid-thickness. A significant increase in the Vickers hardness of the heat affected zone occurred after the first repair and a gradual decrease in the Vickers hardness occurred as the number of repairs increases

The Role of the Bainitic Packet in Control of Impact Toughness in a Simulated CGHAZ of X90 Pipeline Steel

Directory of Open Access Journals (Sweden)

Bin Guo

2016-10-01

Full Text Available X90 pipeline steel was processed with the simulated coarse grain heat affect zone (CGHAZ thermal cycle with heat input varying from 30 kJ/cm to 60 kJ/cm, the microstructures were investigated by means of optical microscope (OM, scanning electron microscope (SEM, electron backscattering diffraction (EBSD, and transmission electron microscope (TEM, and the impact properties were evaluated from the welding thermal cycle treated samples. The results indicate that the microstructure is primarily composed of lath bainite. When decreasing the heat input, both bainite packet and block are significantly refined, and the toughness has an increased tendency due to the grain refinement. The fracture surfaces all present cleavage fracture for the samples with different heat inputs. Moreover, the average cleavage facet size for the CGHAZ is nearly equal to the average bainite packet size, and the bainitic packet boundary can strongly impede the crack propagation, indicating that the bainitic packet is the most effective unit in control of impact toughness in the simulated CGHAZ of X90 pipeline steel.

Micromechanical and internal discontinuity aspects in fusion welded joints

International Nuclear Information System (INIS)

Nur Azida Che Lah; Aidy Ali

2009-01-01

Full text: This paper deals with characterization of macrostructure, microstructure, hardness, elemental compositions and internal discontinuities of ASTM A516 grade 70 fusion welded joints. The welded joints of ASTM A516 grade 70 carbon steel, which are widely used in pressure vessel fabrication were prepared using welding procedures of Manual Metal Arc (MMA), Metal Inert Gas (MIG) and Tungsten Inert Gas (TIG). Local microstructural condition and elemental composition of the welds were characterised using scanning electron microscopy (SEM) in association with energy dispersive X-ray (EDX). Radiography testing was applied to study the common internal weld defects. This comprehensive information provides a practical guide in order to determine the most adequate welding procedure and assisting in understanding the behaviour of the weld zones. (author)

49 CFR 195.226 - Welding: Arc burns.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Welding: Arc burns. 195.226 Section 195.226 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Construction § 195.226 Welding: Arc burns. (a) Each arc burn must be repaired. (b) An arc burn may...

Microstructures and Mechanical Properties of Friction Tapered Stud Overlap Welding for X65 Pipeline Steel Under Wet Conditions

Science.gov (United States)

Xu, Y. C.; Jing, H. Y.; Han, Y. D.; Xu, L. Y.

2017-08-01

This paper exhibits a novel in situ remediation technique named friction tapered stud overlap welding (FTSOW) to repair a through crack in structures and components in extremely harsh environments. Furthermore, this paper presents variations in process data, including rotational speed, stud displacement, welding force, and torque for a typical FTSOW weld. In the present study, the effects of welding parameters on the microstructures and mechanical properties of the welding joints were investigated. Inapposite welding parameters consisted of low rotational speeds and welding forces, and when utilized, they increased the occurrence of a lack of bonding and unfilled defects within the weld. The microstructures with a welding zone and heat-affected zone mainly consisted of upper bainite. The hardness value was highest in the welding zone and lowest in the base material. During the pull-out tests, all the welds failed in the stud. Moreover, the defect-free welds broke at the interface of the lap plate and substrate during the cruciform uniaxial tensile test. The best tensile test results at different depths and shear tests were 721.6 MPa and 581.9 MPa, respectively. The favorable Charpy impact-absorbed energy was 68.64 J at 0 °C. The Charpy impact tests revealed a brittle fracture characteristic with a large area of cleavage.

New In-Field Composite Repair Techniques for Transmission or Distribution Pipelines

Science.gov (United States)

2009-05-18

In-field repair of a damaged pipeline must be performed safely, efficiently, rapidly and reliably. Reinforcement of damaged pipelines is typically accomplished by welding a repair patch and then recoating the repaired area. The welded full-encircleme...

Evaluation of Hydrogen Cracking in Weld Metal Deposited using Cellulosic-Coated Electrodes

Science.gov (United States)

2009-06-16

Cellulosic-coated electrodes (primarily AWS EXX10-type) are traditionally used for "stovepipe" welding of pipelines because they are well suited for deposition of pipeline girth welds and are capable of high deposition rates when welding downhill. De...

Design of cylindrical pipe automatic welding control system based on STM32

Science.gov (United States)

Chen, Shuaishuai; Shen, Weicong

2018-04-01

The development of modern economy makes the demand for pipeline construction and construction rapidly increasing, and the pipeline welding has become an important link in pipeline construction. At present, there are still a large number of using of manual welding methods at home and abroad, and field pipe welding especially lacks miniature and portable automatic welding equipment. An automated welding system consists of a control system, which consisting of a lower computer control panel and a host computer operating interface, as well as automatic welding machine mechanisms and welding power systems in coordination with the control system. In this paper, a new control system of automatic pipe welding based on the control panel of the lower computer and the interface of the host computer is proposed, which has many advantages over the traditional automatic welding machine.

49 CFR 195.234 - Welds: Nondestructive testing.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Welds: Nondestructive testing. 195.234 Section 195... HAZARDOUS LIQUIDS BY PIPELINE Construction § 195.234 Welds: Nondestructive testing. (a) A weld may be... weld. (b) Any nondestructive testing of welds must be performed— (1) In accordance with a written set...

Corrosion resistance and microstructure of alloy 625 weld overlay on ASTM A516 grade 70

Energy Technology Data Exchange (ETDEWEB)

Moradi, Mohammad J. [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Petroleum Engineering Dept.; Ketabchi, Mostafa [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Mining and Metallurgical Engineering Dept.

2016-02-01

Nickel-based alloys are a crucial class of materials because of their excellent corrosion resistance. In the present study, single layer and two layers alloy 625 weld overlays were deposited by GTAW process on A516 grade 70 carbon steel. The dilution in terms of Fe, Ni, Mo and Nb content was calculated in 30 points of weld overlay. Microstructure observations showed that alloy 625 had austenitic structure with two types of Laves and NbC secondary phases. The uniform and pitting corrosion resistance of alloy 625 weld overlay as casted and as forged were evaluated in accordance with ASTM G48-2011 standard at different temperatures to determine the weight loss and critical pitting temperature. For achieving a better comparison, samples from alloy 625 as casted and as forged were tested under the same conditions. The results point out that single layer alloy 625 weld overlay is not suitable for chloride containing environments, two layers alloy 625 weld overlay and alloy 625 as casted have acceptable corrosion resistance and almost the same critical pitting temperature. Alloy 625 as forged has the best corrosion resistance and the highest critical pitting temperature among all test specimens. Also, the corrosion behavior was evaluated in accordance with ASTM G28 standard. The corrosion rate of single layer weld overlay was unacceptable. The average corrosion rate of two layers weld overlay and in casted condition were 35.82 and 33.01 mpy, respectively. [German] Nickellegierungen sind aufgrund ihres exzellenten Korrosionswiderstandes eine bedeutende Werkstoffklasse. In der diesem Beitrag zugrunde liegenden Studie wurden mittels WIG-Schweissens ein- und zweilagige Schweissplattierungen auf den Kohlenstoffstahl A516 (Grade 70) aufgebracht. Die Vermischung in Form des Fe-, Ni-, Mo- und Nb-Gehaltes wurde an 30 Punkten der Schweissplattierungen berechnet. Die mikrostrukturellen Untersuchungen ergaben, dass die Legierung 625 eine austenitische Struktur mit zwei Arten von

49 CFR 195.214 - Welding procedures.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Welding procedures. 195.214 Section 195.214... PIPELINE Construction § 195.214 Welding procedures. (a) Welding must be performed by a qualified welder in accordance with welding procedures qualified under Section 5 of API 1104 or Section IX of the ASME Boiler and...

49 CFR 179.11 - Welding certification.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Welding certification. 179.11 Section 179.11 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Design Requirements § 179.11 Welding certification. (a) Welding procedures, welders and fabricators shall...

Engineering critical assessment of PETROBRAS Camarupim pipeline

Energy Technology Data Exchange (ETDEWEB)

Gordon, J.R. [Microalloying International, Houston, TX (United States); Gatlin, R.W. [Global Industries, Rio de Janeiro, RJ (Brazil); Zumpano Junior, P.; Kaspary, T. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

2009-12-19

This paper presents details of an Engineering Critical Assessment (ECA) performed to develop girth weld flaw acceptance criteria for the PETROBRAS Camarupim Pipeline which was installed in Espirito Santo Basin, ES, offshore Brazil in May 2008 by Global Industries. The pipeline was constructed using 24-inch diameter API Grade X65 pipe with wall thicknesses of 0.875-inch (22.2 mm) and 1.00 inch (25.4 mm). Although the Camarupim pipeline will initially transport sweet gas there is the potential for mildly sour service operation in mid to late life. To assess the effect of sour service on the material toughness properties a series of slow strain rate fracture toughness tests were performed in a Project representative sour service environment. In addition the results of sour service fatigue crack growth tests were analyzed to develop a conservative sour service fatigue crack growth law for the ECA analysis. (author)

Methodological development and characterization of welded joints in Poly (vinylidene fluoride) (PVDF); Desenvolvimento metodologico e caracterizacao de juntas soldadas de PVDF

Energy Technology Data Exchange (ETDEWEB)

Cedrola, S.M.L.; Costa, M.F. da; Pasqualino, I.P., E-mail: samanta@metalmat.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

2010-07-01

Pipelines are of great concern in the transport sector of oil and gas industries, mainly due to the natural internal aging process caused by contact with the different transported fluids. Installation of polymeric pipes called liners is a good option for rehabilitation of long segments of deteriorated pipelines. Among the potential materials for such application is Poly (vinylidene fluoride) (PVDF). Meanwhile the installation process cannot be carried out in one single step and the polymeric pipe must be cut in sections that are welded during the installation process. In this research welding methodology was studied aiming to optimize welding conditions and the mechanical properties of the joined materials. The first step was processing the PVDF via compression molding on different conditions. Then, the sample was cut and butt-welded. Welding parameters such as, time control, temperature and contact pressure were studied. Afterwards, the stress-strain properties of the welded material was evaluated and physical characterization was carried by x-ray diffraction (DRX). (author)

49 CFR 195.208 - Welding of supports and braces.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Welding of supports and braces. 195.208 Section 195.208 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... HAZARDOUS LIQUIDS BY PIPELINE Construction § 195.208 Welding of supports and braces. Supports or braces may...

Numerical evaluation of multipass welding temperature field in API 5L X80 steel welded joints

Directory of Open Access Journals (Sweden)

J Nóbrega

2016-10-01

Full Text Available Many are the metallurgical changes suffered by materials when subjected to welding thermal cycle, promoting a considerable influence on the welded structures thermo mechanical properties. In project phase, one alternative for evaluating the welding cycle variable, would be the employment of computational methods through simulation. So, this paper presents an evaluation of the temperature field in a multipass welding of API 5L X80 steel used for oil and gas transportation, using the ABAQUS ® software, based on Finite Elements Method (FEM. During the simulation complex phenomena are considerable including: Variation in physical and mechanical properties of materials as a function of temperature, welding speed and the different mechanisms of heat exchange with the environment (convection and radiation were used. These considerations allow a more robust mathematical modeling for the welding process. An analytical heat source proposed by Goldak, to model the heat input in order to characterize the multipass welding through the GTAW (Gas Tungsten Arc Welding process on root and the SMAW (Shielded Metal Arc Welding process for the filling passes were used. So, it was possible to evaluate the effect of each welding pass on the welded joint temperature field, through the temperature peaks and cooling rates values during the welding process.

Development of corrosion defect assessment program for API X65 gas pipelines

International Nuclear Information System (INIS)

Choi, Jae Boong; Kim, Youn Ho; Kim, Young Jin; Goo, Bon Geol; Kim, Yound Pyo; Baek, Jong Hyun; Kim, Woo Sik

2001-01-01

Pipelines have the highest capacity and are the safest and the least environmentally disruptive way for gas or oil transmission. Recently, failures due to corrosion defects have become of major concern in maintaining pipeline integrity. A number of solutions have been developed for the assessment of remaining strength of corroded pipelines. However, these solutions are known to be dependent on material properties and pipeline geometries. In this paper, a fitness-for-purpose type limit load solution for corroded gas pipelines made of the X65 steel is proposed. For this purpose, a series of burst tests with various types of corrosion defects are performed. Finite element simulations are carried out to derive an appropriate failure criterion. And then, further, extensive finite element analyses are performed to obtain the FFP type limit load solution for corroded X65 gas pipelines as a function of defect depth, length and pipeline geometry. And also, a window based computer program for the assessment of corrosion defect, which is named as COPAP(COrroded Pipeline Assessment Program) has been developed on the basis of proposed limit load solution

Study of Laser Welding of HCT600X Dual Phase Steels

Directory of Open Access Journals (Sweden)

Švec Pavol

2014-12-01

Full Text Available The effects of beam power and welding speed on microstructure, microhardnes and tensile strength of HCT600X laser welded steel sheets were evaluated. The welding parameters influenced both the width and the microstructure of the fusion zone and heat affected zone. The welding process has no effect on tensile strength of joints which achieved the strength of base metal and all joints fractured in the base metal.

Passivation process of X80 pipeline steel in bicarbonate solutions

Science.gov (United States)

Zhou, Jian-Long; Li, Xiao-Gang; Du, Cui-Wei; Pan, Ying; Li, Tao; Liu, Qian

2011-04-01

The passivation process of X80 pipeline steel in bicarbonate solutions was investigated using potentiodynamic, dynamic electrochemical impedance spectroscopy (DEIS), and Mott-Schottky measurements. The results show that the shape of polarization curves changes with HCO{3/-} concentration. The critical `passive' concentration is 0.009 mol/L HCO{3/-} for X80 pipeline steel in bicarbonate solutions. No anodic current peak exists in HCO3/- solutions when the concentration is lower than 0.009 mol/L, whereas there are one and two anodic current peaks when the HCO3/- concentration ranges from 0.009 to 0.05 mol/L and is higher than 0.1 mol/L, respectively. DEIS measurements show that there exist active dissolution range, transition range, pre-passive range, passive layer formation range, passive range, and trans-passive range for X80 pipeline steel in the 0.1 mol/L HCO{3/-} solutions. The results of DEIS measurements are in complete agreement with the potentiodynamic diagram. An equivalent circuit containing three sub-layers is used to explain the Nyquist plots in the passive range. Analyses are well made for explaining the corresponding fitted capacitance and impedance. The Mott-Schottky plots show that the passive film of X80 pipeline steel is an n-type semiconductor, and capacitance measurements are in good accordance with the results of DEIS experiment.

Research on Soft Reduction Amount Distribution to Eliminate Typical Inter-dendritic Crack in Continuous Casting Slab of X70 Pipeline Steel by Numerical Model

Science.gov (United States)

Liu, Ke; Wang, Chang; Liu, Guo-liang; Ding, Ning; Sun, Qi-song; Tian, Zhi-hong

2017-04-01

To investigate the formation of one kind of typical inter-dendritic crack around triple point region in continuous casting(CC) slab during the operation of soft reduction, fully coupled 3D thermo-mechanical finite element models was developed, also plant trials were carried out in a domestic continuous casting machine. Three possible types of soft reduction amount distribution (SRAD) in the soft reduction region were analyzed. The relationship between the typical inter-dendritic cracks and soft reduction conditions is presented and demonstrated in production practice. Considering the critical strain of internal crack formation, a critical tolerance for the soft reduction amount distribution and related casing parameters have been proposed for better contribution of soft reduction to the internal quality of slabs. The typical inter-dendritic crack around the triple point region had been eliminated effectively through the application of proposed suggestions for continuous casting of X70 pipeline steel in industrial practice.

The selection of ultrasonic transducers for inspection of pipeline girth welds. Vol. 3. Evaluation of the pitch-catch technique for examination of the body region

Energy Technology Data Exchange (ETDEWEB)

Glover, A G; Fingerhut, M P; Dorling, D V

1988-10-01

Research was conducted to develop an ultrasonic inspection design for the nondestructive evaluation of pipeline girth welds made by the mechanized gas metal arc (GMA) welding process for onshore and offshore pipeline construction. This report describes the work carried out to evaluate the performance to the pitch-catch technique with respect to its ability to examine the body region of mechanized GMA welds in 19.5 mm thick material. Evaluation of the pitch-catch technique was carried out on simulated and real weld defects. Results show that an inspection design method and criteria can be specified for the detection of lack of sidewall fusion defects in the body region of mechanized GMA welds. The criteria specified a pitch-catch technique using a 2.25 MHz 45{degrees} transmitter and a 2.25 MHz 55{degrees} receiver probe. A single pair of these transducers can inspect wall thickness from 9.7 mm to 23.0 mm. The pitch-catch technique evaluated on 19.5 mm wall thickness materials demonstrated that the detection goal of projected depth with a signal-to-noise ratio of greater than 12dB could be met, and that no problems occurred with false indications or missed defects. High sensitivities to small defects in the body region were obtained using a single pair of pitch-catch probes that inspected the body region as a single plane. 4 refs., 14 figs., 6 tabs.

Creep properties of EB welded joint on Hastelloy X

International Nuclear Information System (INIS)

Arata, Yoshiaki; Susei, Shuzo; Shimizu, Shigeki; Satoh, Keisuke; Nagai, Hiroyoshi.

1980-01-01

In order to clarify the creep properties of EB welds on Hastelloy X which is one of the candidate alloys for components of VHTR, creep tests on EB weld metal and welded joint were carried out. The results were discussed in comparison with those of base metal and TIG welds. Further, EB welds were evaluated from the standpoint of high temperature structural design. The results obtained are summarized as follows. 1) Both creep rupture strengths of EB weld metal and EB welded joint are almost equal to that of base metal, but those of TIG welds are lower than base metal. As for the secondary creep rate, EB weld metal is higher and TIG weld metal is lower than base metal. As for the time to onset of tertiary creep, no remarkable difference among base metal, EB weld metal and TIG weld metal is observed. 2) In case of EB weld metal, although anisotropy is slightly observed, the ductility is same or more as compared with base metal. In case of TIG weld metal, on the contrary, anisotropy is not observed and the ductility is essentially low. 3) Such rupture morphology of EB weld metal as appears to have resulted from interconnection of voids which occurred at grain boundary is similar to base metal. In case of TIG weld metal, however, many cracks with sharp tips are observed at grain boundary, and the rupture appears to have occurred in brittle by propagation and connection of the cracks. 4) It can be said from the standpoint of high temperature structural design that EB welding is very suitable to welding for structure where creep effects are significant, because both of the creep ductility and the rupture strength are almost equal to those of base metal. (author)

Combined Effect of Alternating Current Interference and Cathodic Protection on Pitting Corrosion and Stress Corrosion Cracking Behavior of X70 Pipeline Steel in Near-Neutral pH Environment

Directory of Open Access Journals (Sweden)

Liwei Wang

2018-03-01

Full Text Available Influence of alternating current (AC on pitting corrosion and stress corrosion cracking (SCC behavior of X70 pipeline steel in the near-neutral pH environment under cathodic protection (CP was investigated. Both corrosion and SCC are inhibited by −0.775 VSCE CP without AC interference. With the superimposition of AC current (1–10 mA/cm2, the direct current (DC potential shifts negatively under the CP of −0.775 VSCE and the cathodic DC current decreases and shifts to the anodic direction. Under the CP potential of −0.95 VSCE and −1.2 VSCE, the applied AC current promotes the cathodic reaction and leads to the positive shift of DC potential and increase of cathodic current. Local anodic dissolution occurs attributing to the generated anodic current transients in the positive half-cycle of the AC current, resulting in the initiation of corrosion pits (0.6–2 μm in diameter. AC enhances the SCC susceptibility of X70 steel under −0.775 VSCE CP, attributing to the promotion of anodic dissolution and hydrogen evolution. Even an AC current as low as 1 mA/cm2 can enhance the SCC susceptibility.

Inspection of welded joints and cords using industrial x-ray and gamma radiography

International Nuclear Information System (INIS)

Escobar R, E.J.

2000-01-01

The first part of this work contains five chapters related to theoretical aspects and basic knowledge of welding metallurgy, welding, welded joint discontinuity, non-destructive testing (NDT) and industrial x-rays. The second part contains experimental works applied and carried out by the Peruvian Institute of Nuclear Energy (IPEN). Due to the importance of identifying and applying the different methods of NDT in the industry's quality control, more emphasis is placed on industrial x-ray and gamma radiography, a method that involves the radiographic inspection of welded joints and cords

Effect of post weld heat treatment on the microstructure and tensile properties of activated flux TIG welds of Inconel X750

Energy Technology Data Exchange (ETDEWEB)

Ramkumar, K. Devendranath, E-mail: ramdevendranath@gmail.com; Ramanand, R.; Ameer, Ajmal; Simon, K. Aghil; Arivazhagan, N.

2016-03-21

This study addresses the effect of post weld heat treatment on the fusion zone microstructure and the mechanical properties of activated flux tungsten inert gas (A-TIG) weldments of Inconel X750. In this study, a compound flux of 50% SiO{sub 2}+50% MoO{sub 3} was used for A-TIG welding of the samples. Comparative studies on the microstructure and mechanical properties have been made on the weldments both in the as-welded and post weld heat treated conditions. Direct ageing post weld heat treatment (PWHT) was carried out at 705 °C for 22 h on the A-TIG weldment to assess the structure–property relationships. It was inferred that direct ageing post weld heat treatment resulted in better tensile strength (1142 MPa) compared to the as-welded coupons (736 MPa). The joint efficiencies of the as-welded and post weld heat treated conditions were found to be 60.7% and 94.07% respectively. The impact toughness of the as-welded coupons were found to be greater than the post weld heat treated samples; however the impact toughness of the welds are greater than the parent metal employed in both the cases. This study also attested the detailed structure–property relationships of A-TIG weldments using the combined techniques of optical and scanning electron microscopy, Electron Dispersive X-ray Analysis (EDAX) techniques.

Effect of post weld heat treatment on the microstructure and tensile properties of activated flux TIG welds of Inconel X750

International Nuclear Information System (INIS)

Ramkumar, K. Devendranath; Ramanand, R.; Ameer, Ajmal; Simon, K. Aghil; Arivazhagan, N.

2016-01-01

This study addresses the effect of post weld heat treatment on the fusion zone microstructure and the mechanical properties of activated flux tungsten inert gas (A-TIG) weldments of Inconel X750. In this study, a compound flux of 50% SiO_2+50% MoO_3 was used for A-TIG welding of the samples. Comparative studies on the microstructure and mechanical properties have been made on the weldments both in the as-welded and post weld heat treated conditions. Direct ageing post weld heat treatment (PWHT) was carried out at 705 °C for 22 h on the A-TIG weldment to assess the structure–property relationships. It was inferred that direct ageing post weld heat treatment resulted in better tensile strength (1142 MPa) compared to the as-welded coupons (736 MPa). The joint efficiencies of the as-welded and post weld heat treated conditions were found to be 60.7% and 94.07% respectively. The impact toughness of the as-welded coupons were found to be greater than the post weld heat treated samples; however the impact toughness of the welds are greater than the parent metal employed in both the cases. This study also attested the detailed structure–property relationships of A-TIG weldments using the combined techniques of optical and scanning electron microscopy, Electron Dispersive X-ray Analysis (EDAX) techniques.

Texture, microstructure, and fractal features of the low-cycle fatigue failure of the metal in pipeline welded joints

Science.gov (United States)

Usov, V. V.; Gopkalo, E. E.; Shkatulyak, N. M.; Gopkalo, A. P.; Cherneva, T. S.

2015-09-01

Crystallographic texture and fracture features are studied after low-cycle fatigue tests of laboratory specimens cut from the base metal and the characteristic zones of a welded joint in a pipeline after its longterm operation. The fractal dimensions of fracture surfaces are determined. The fractal dimension is shown to increase during the transition from ductile to quasi-brittle fracture, and a relation between the fractal dimension of a fracture surface and the fatigue life of the specimen is found.

Welding facilities for NPP assembling

International Nuclear Information System (INIS)

Rojtenberg, S.S.

1987-01-01

Recommendations concerning the choice of equipment for welding in pre-assembling work shops, in the enlarging assembling shops and at the assembling site, are given. Advanced production automatic welders and semiautomatic machines, applied during the NPP equipment assembling as well as automatic machines specially produced for welding the main reactor components and pipelines are described. Automatic and semiautomatic machine and manual welding post supply sources are considered

Comparative study on the stress corrosion cracking of X70 pipeline steel in simulated shallow and deep sea environments

Energy Technology Data Exchange (ETDEWEB)

Sun, Feilong [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Key Laboratory of Corrosion and Protection of Ministry of Education, Beijing 100083 (China); China Building Material Test & Certification Group Co. Ltd., Beijing 100024 (China); Ren, Shuai [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Key Laboratory of Corrosion and Protection of Ministry of Education, Beijing 100083 (China); Li, Zhong [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada T6G 2G6 (Canada); Liu, Zhiyong, E-mail: liuzhiyong7804@ustb.edu.cn [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Key Laboratory of Corrosion and Protection of Ministry of Education, Beijing 100083 (China); Li, Xiaogang; Du, Cuiwei [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Key Laboratory of Corrosion and Protection of Ministry of Education, Beijing 100083 (China)

2017-02-08

The stress corrosion cracking (SCC) behavior of X70 steel in simulated shallow and deep sea environments was studied using potentiodynamic polarization measurement, a slow strain rate tensile (SSRT) test and scanning electron microscopy (SEM). The results indicate that the predominant cathodic reaction changes from an oxygen reduction reaction to the hydrogen evolution reaction as the dissolved oxygen (DO) content decreases. In the simulated deep sea environment, the SCC susceptibility of X70 steel decreased first, reached its lowest point at 15 MPa and then increased as the simulated sea hydrostatic pressure (HP) further increased. This is consistent with the regularity for the change of the cathodic hydrogen evolution reaction current density i{sub H} at E{sub corr}, which indicates that the HP may influence the SCC susceptibility of X70 steel by changing the permeated hydrogen concentration.

Stress and Strain State Analysis of Defective Pipeline Portion

Science.gov (United States)

Burkov, P. V.; Burkova, S. P.; Knaub, S. A.

2015-09-01

The paper presents computer simulation results of the pipeline having defects in a welded joint. Autodesk Inventor software is used for simulation of the stress and strain state of the pipeline. Places of the possible failure and stress concentrators are predicted on the defective portion of the pipeline.

Investigation on potential SCC in gas transmission pipeline in China

Energy Technology Data Exchange (ETDEWEB)

Jian, S. [Petroleum Univ., Beijing (China); Zupei, Y.; Yunxin, M. [China Petroleum Pipeline Corp., Beijing (China). Science and Technology Center

2004-07-01

Stress corrosion cracking (SCC) is a common phenomenon that occurs on the outer surfaces of buried pipelines. This paper investigated aspects of SCC on 3 transmission pipelines on the West-East Gas Pipeline Project in China. The study was comprised of 3 different investigations: (1) an investigation of SCC cases on constructed pipelines; (2) an evaluation of SCC sensitivity of pipeline steels in typical soil environments; and (3) an analysis of soil environments and operation conditions of western pipelines. The study included a review of pipeline corrosion investigations, as well as an examination of pipeline failure cases. Investigative digs were conducted at 21 sites to test soil chemistries. Slow strain rate stress were conducted to evaluate SCC sensitivity of steel pipelines used in China. Potentiodynamic polarization tests were conducted to characterize the electrochemical behaviour of the X70 line pipe steel in different soil environments. Results of the study showed that the environmental conditions in many locations in China contributed to SCC in pipelines. SCC was observed on the surface of X70 steel pipe specimens in both marsh and saline environments. Seasonal temperature changes also contributed additional stress on pipelines. The movement of soil bodies in mountainous areas also contributed to stress and coating damage. It was concluded that proper cathodic protection can alleviate concentrations of local solutions under disbanded coatings. Overprotection of SCC will accelerate the growth of cracks and the degradation of coatings. Samples gathered from the solutions found under the disbanded coatings of pipelines will be used to form part of a reference database for predicting SCC in oil and gas pipelines in the future. 2 refs., 4 tabs., 5 figs.

49 CFR 178.61 - Specification 4BW welded steel cylinders with electric-arc welded longitudinal seam.

Science.gov (United States)

2010-10-01

... Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS... inspection must conform to the techniques and acceptability criteria set forth in CGA Pamphlet C-3. When... prescribed tests to be acceptable. Repair of welded seams by welding is authorized provided that all...

Uma breve revisão histórica do desenvolvimento da soldagem dos aços API para tubulações A brief history review of development on API steels welding for pipeline

Directory of Open Access Journals (Sweden)

Jaime Casanova Soeiro Junior

2013-06-01

Full Text Available Este trabalho enfoca o desenvolvimento dos aços API para tubulações desde o aço API 5L X42, desenvolvido em 1948, através de laminação a quente seguida de tratamento térmico. Desde então foram feitos diferentes desenvolvimentos visando aumentar a resistência mecânica e a tenacidade, além de melhorar a soldabilidade. Entre eles, a adição de elementos de liga, produzindo os aços ARBL e a utilização de rotas de processamento termomecânico durante a laminação. Inicialmente a rota utilizada era a laminação a quente controlada (TMCR, com utilização de elemento microligante como Nb para os aços X60 e o conjunto Nb e V para os aços X65 e X70, associado a uma redução do teor de carbono. Posteriormente foi implantada a rota de fabricação do aço por laminação controlada seguida de resfriamento controlado (TMCP, com redução de carbono e adição de Nb e Ti para os aços X80, e adições de Mo, Nb, Be Ti para os X100. A redução do carbono foi motivada também para melhorar a sua soldabilidade e, por este motivo, estes aços são soldados por diferentes processos de soldagem, como o eletrodo revestido. Desenvolvimentos recentes com raiz feita com MAG-TC e enchimento com arame tubular tem dado resultados animadores.This paper is a brief history on the development of pipelines steels since the API 5L X42 steel, developed in 1948 by hot rolling followed by heat treatment. Subsequently different developments were made to increase the strength and toughness of these materials, and to improve their weldability. Among them, the addition of microalloying elements, producing HSLA steels and thermomechanical processing routes during hot rolling. Initially the route used was the controlled hot rolling (TMCR, together with microalloying element such as Nb for X60 steel and Nb plus V for X65 and X70 steels, associated with a reduction in carbon content. Later, the thermomechanical controlled process (TMCP manufacturing route was

Avaliação da microestrutura e propriedades mecânicas de metais de solda obtidos por processos de soldagem manual e automatizado utilizado na soldagem de aço API 5L X80 Evaluation of microstructure and mechanical properties of weld metals obtained by manual and automated welding process used in the welding of API 5L X80 steel

Directory of Open Access Journals (Sweden)

Siderley Fernandes Albuquerque

2011-12-01

Full Text Available O objetivo do trabalho foi avaliar as características da zona termicamente afetada (ZTA e a microestrutura e propriedades mecânicas de metais de solda de juntas soldadas do aço API 5L X80, obtidos para quatro diferentes procedimentos de soldagem utilizando processos manuais e automatizados. Para isto, chapas do referido aço foram soldadas por processo manual ao Arco Elétrico com Eletrodo Revestido (SMAW, utilizando 473 e 673 K como temperaturas de interpasses e o eletrodo celulósico AWS E8010-G como consumível; por processo ao Arco Elétrico com Arame Tubular (FCAW robotizado, utilizando o arame AWS E71T- 1C como metal de adição e argônio com 25%CO2 como gás de proteção; por processo a Arco Elétrico com Eletrodo de Tungstênio (GTAW mecanizado na raiz da solda, usando o arame ER70S-3 e argônio como gás de proteção. As análises microestruturais foram relacionadas com os resultados de ensaios de impacto Charpy nos metais de solda e com os perfis de microdureza Vickers ao longo da junta soldada. Os resultados indicaram maiores percentuais de Ferrita Acicular e maiores valores de resistência ao impacto nos metais de solda e uma menor extensão e granulometria da ZTA, associado ao procedimento de soldagem utilizando processo automatizado com maior velocidade de soldagem.The objective of this work was to evaluate the heat affected zone characteristics and weld metals microstructure and mechanical properties of API 5L X80 steel welded joints, obtained for four different welding procedures using manual and automated processes. For this, plates of this steel were welded by manual Shielded Metal Arc Welding (SMAW process with interpasses temperatures of 473 e 673 K, and using AWS E8010-G electrode as filler metals; robotized Flux Cored Arc Welding (FCAW process, using AWS E71T-1C wire and Ar25%CO2 as consumable and mechanized Gas Tungsten Arc Welding (GTAW process, for the root pass using AWS ER70S-3 and Ar as consumable .The

Dry hyperbaric gas metal arc welding of subsea pipelines: experiments and modeling

Energy Technology Data Exchange (ETDEWEB)

Azar, Amin S.

2012-07-01

Ambitions in exploration of oil and gas fields at deeper water depth require continuous investigation and maintenance. The transportation pipelines laid in deep waters are both subjected to corrosion and buckling due to environmental phenomena. They may also often undergo branching (namely hot tapping) to redirect (or add to) the transportation paths. Mechanical joints and welding are both considered as available alternatives when sectioning and replacement of the pipes at shallow waters is necessary, yet, welding is more promising for deep waters where remote operation is central. Fusion welding on the other hand comprises several technological detractions for sound operations under high ambient pressures disregarding its low cost and flexibility. The foremost detracting phenomenon in the arc welding is called 'arc root constriction', which is defined as arc geometry shrinkage under the increased pressure. Consequently, the power delivery to the weld pool at different pressure levels is a major worry. Effects of ionization and dissociation energies of different gases and mixtures, partial pressure of environmental gases including hydrogen and oxygen, gasification and degasification of the weld metal, inclusions that affect the phase transformation, absorption and desorption kinetics, oxidation and deoxidation reactions and many more are the phenomena that can possibly be altered by the gas type and ambient pressure level. Spattering and fume generation is a problematic issue since the arc is rather unstable under high pressure. Thus, seeking the effect of different chamber gas mixtures on welding parameters, final microstructure and mechanical properties is the main objective of this work.Statistical analysis of the collected voltage and current waveforms is carried out to identify the source of arc misbehavior and instability (discussed in Paper I). The stochastic parameters is related to the electrical stability and resolved into a number of varying

Weldability and weld performance of a special grade Hastelloy-X modified for high-temperature gas-cooled reactors

International Nuclear Information System (INIS)

Shimizu, S.; Mutoh, Y.

1984-01-01

The characteristics of weld defects in the electron beam (EB) welding and the tungsten inert gas (TIG) arc welding for Hastelloy-XR, a modified version of Hastelloy-X, are clarified through the bead-on-plate test and the Trans-Varestraint test. Based on the results, weldabilities on EB and TIG weldings for Hastelloy-XR are discussed and found to be almost the same as Hastelloy-X. The creep rupture behaviors of the welded joints are evaluated by employing data on creep properties of the base and the weld metals. According to the evaluation, the creep rupture strength of the EB-welded joint may be superior to that of the TIG-welded joint. The corrosion test in helium containing certain impurities is conducted for the weld metals. There is no significant difference of such corrosion characteristics as weight gain, internal oxidation, depleted zone, and so on between the base and the weld metals. Those are superior to Hastelloy-X

Micro-focus x-ray inspection of the bearing pad welded by laser for CANDU fuel element

International Nuclear Information System (INIS)

Kim, W. K.; Kim, S. S.; Lee, J. W.; Yang, M. S.

2001-01-01

To attach the bearing pads on the surface of CANDU fuel element, laser welding technique has been reviewed to replace brazing technology which is complicate process and makes use of the toxic beryllium. In this study, to evaluate the soundness of the weld of the bearing pad of CANDU fuel element, a precise X-ray inspection system was developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The weld of the bearing pad welded by Nd:YAG laser has been inspected by the developed inspection system. Image processing technique has been applied to reduce random noise and to enhance the contrast of the X-ray image. A few defects on the weld of the bearing pads have been detected by the X-ray inspection process

Self-propelled pulse X-ray apparatus Sirena-1

International Nuclear Information System (INIS)

Danil'chenko, N.T.; Ershov, L.S.; Il'chenko, A.V.; Krasil'nikov, S.B.; Kristalinskij, A.L.; Lozovoj, L.N.; Markov, S.N.; Morgovskij, L.Ya.

1984-01-01

The structure and specifications of a self-propelled pulse X-ray apparatus ''Sirena-1'' for testing oilt and gas pipelines welded joints are described. The apparatus is designed on the base of pulse X-ray apparatus MIRA. Apparatus control is realized by means of the 137 Cs source or manual control desk. The apparatus ensures perfect control sensitivity

Determination of Elements and Carbon Content of Stainless Steel Welded Pipeline

Directory of Open Access Journals (Sweden)

Pavel Hudeček

2016-01-01

Full Text Available Find out defects or problems of welds are not so simple from time to time. Specially, if weld has been made in rough environmental conditions like high temperature, dusty wind and humidity. It is important to assure have good conditions to realize basic step of welding. For welding, have been used welding procedures specification and procedure qualification record. However, difficult conditions, documentations rightness or human errors are always here. Common weld defects like cracks, porosity, lack of penetration and distortion can compromise the strength of the base metal, as well as the integrity of the weld. According of site inspection, there were suspicion of inclusions, leaker or segregation in root of weld. Surface treatment after welding and keep the intervals between single welds to not overheat the pipes. To recognize those suspicions, mechanical testing around weld joint, determination of carbon content and inductively coupled plasma atomic emission spectroscopy will be done.

Lap weld joint modelling and simulation of welding in programme SYSWELD

Directory of Open Access Journals (Sweden)

Koňár Radoslav

2018-01-01

Full Text Available Simulations of the welding process for applications of practice using SYSWELD are presented. This paper presents simulation of welding in the repair of high-pressure gas pipeline with steel sleeve with composite filling. Material of experimental sample was steel S355. The simulations in SYSWELD divided in to two parts: the thermal simulation followed by the mechanical simulation. The results of the numerical model, which are listed in article are compared to real experiments.

X-ray tomographic in-service inspection of girth welds - The European project TomoWELD

International Nuclear Information System (INIS)

Ewert, Uwe; Redmer, Bernhard; Walter, David; Thiessenhusen, Kai-Uwe; Bellon, Carsten; Nicholson, P. Ian; Clarke, Alan L.; Finke-Härkönen, Klaus-Peter

2015-01-01

The new standard 'ISO 17636-2:2013: Non-destructive testing of welds - Radiographic testing - Part 2: X- and gamma-ray techniques with digital detectors', defines the practice for radiographic inspection of welded pipes for manufacturing and in-service inspection. It is applied in Europe for inspections of pipe welds in nuclear power plants as well as in chemical plants and allows a faster inspection with digital detector arrays (DDA) than with film. Nevertheless, it does not allow the evaluation of the depth and shape of volumetric and planar indications. In 2001 a planar tomography scanner, TomoCAR, was introduced for mechanized radiographic testing (RT) inspection and non-destructive measurement of cross sections. The project TomoWELD is based on a new concept of the scan geometry, an enhanced GPU based reconstruction, and the application of a new generation of photon counting DDAs based on CdTe crystal CMOS hybrids. The new detector permits the selection of energy thresholds to obtain an optimum energy range and reduction of the influence of scattered radiation. The concept and first measurements are presented. Flaw depth and shape of volumetric and planar irregularities can be determined

X-ray tomographic in-service inspection of girth welds - The European project TomoWELD

Energy Technology Data Exchange (ETDEWEB)

Ewert, Uwe, E-mail: uwe.ewert@bam.de; Redmer, Bernhard, E-mail: uwe.ewert@bam.de; Walter, David, E-mail: uwe.ewert@bam.de; Thiessenhusen, Kai-Uwe, E-mail: uwe.ewert@bam.de; Bellon, Carsten, E-mail: uwe.ewert@bam.de [BAM Bundesanstalt für Materialforschung, Berlin (Germany); Nicholson, P. Ian, E-mail: ian.nicholson@twi.co.uk [TWI Technology Centre Wales, Port Talbot (United Kingdom); Clarke, Alan L. [TWI Technology Centre Wales, Port Talbot (United Kingdom); Finke-Härkönen, Klaus-Peter, E-mail: klaus.harkonen@ajat.fi [Oy AJAT Ltd., Helsinki (Finland)

2015-03-31

The new standard 'ISO 17636-2:2013: Non-destructive testing of welds - Radiographic testing - Part 2: X- and gamma-ray techniques with digital detectors', defines the practice for radiographic inspection of welded pipes for manufacturing and in-service inspection. It is applied in Europe for inspections of pipe welds in nuclear power plants as well as in chemical plants and allows a faster inspection with digital detector arrays (DDA) than with film. Nevertheless, it does not allow the evaluation of the depth and shape of volumetric and planar indications. In 2001 a planar tomography scanner, TomoCAR, was introduced for mechanized radiographic testing (RT) inspection and non-destructive measurement of cross sections. The project TomoWELD is based on a new concept of the scan geometry, an enhanced GPU based reconstruction, and the application of a new generation of photon counting DDAs based on CdTe crystal CMOS hybrids. The new detector permits the selection of energy thresholds to obtain an optimum energy range and reduction of the influence of scattered radiation. The concept and first measurements are presented. Flaw depth and shape of volumetric and planar irregularities can be determined.

Ultrasonic testing standard of fusion joint for polythylene(PE) pipeline

International Nuclear Information System (INIS)

Lee, Euy Jong; Hur, Sam Suk; Chae, Gug Byeong

2006-01-01

The polyethylene(PE) pipes are widely used to transport city gas worldwide with steel pipes. Generally, Steel pipe are used for high pressure line and PE pipe for low pressure line whose pressure is less than 4 kg/m 2 . The steel pipe line are subject to 100 percent Radiographic Testing(RT) during installation stage, on the contrary, there has been no the established testing method for the welding fusion joint of polyethylene pipes, so all quality control is limited only Visual Testing(VT) or management of Fusion welding equipment. Even though PE pipeline is exposed to lower pressure than steel pipeline, the gas leakage from PE pipe may result in almost the same serious consequence from steel pipeline. So, it is necessary to develop the reliable testing standard for PE pipeline from the point of view of NDT engineers.

Implementing an X-ray validation pipeline for the Protein Data Bank

International Nuclear Information System (INIS)

Gore, Swanand; Velankar, Sameer; Kleywegt, Gerard J.

2012-01-01

The implementation of a validation pipeline, based on community recommendations, for future depositions of X-ray crystal structures in the Protein Data Bank is described. There is an increasing realisation that the quality of the biomacromolecular structures deposited in the Protein Data Bank (PDB) archive needs to be assessed critically using established and powerful validation methods. The Worldwide Protein Data Bank (wwPDB) organization has convened several Validation Task Forces (VTFs) to advise on the methods and standards that should be used to validate all of the entries already in the PDB as well as all structures that will be deposited in the future. The recommendations of the X-ray VTF are currently being implemented in a software pipeline. Here, ongoing work on this pipeline is briefly described as well as ways in which validation-related information could be presented to users of structural data

Implementing an X-ray validation pipeline for the Protein Data Bank

Energy Technology Data Exchange (ETDEWEB)

Gore, Swanand; Velankar, Sameer; Kleywegt, Gerard J., E-mail: gerard@ebi.ac.uk [EMBL–EBI, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD (United Kingdom)

2012-04-01

The implementation of a validation pipeline, based on community recommendations, for future depositions of X-ray crystal structures in the Protein Data Bank is described. There is an increasing realisation that the quality of the biomacromolecular structures deposited in the Protein Data Bank (PDB) archive needs to be assessed critically using established and powerful validation methods. The Worldwide Protein Data Bank (wwPDB) organization has convened several Validation Task Forces (VTFs) to advise on the methods and standards that should be used to validate all of the entries already in the PDB as well as all structures that will be deposited in the future. The recommendations of the X-ray VTF are currently being implemented in a software pipeline. Here, ongoing work on this pipeline is briefly described as well as ways in which validation-related information could be presented to users of structural data.

Tensometry technique for X-ray diffraction in applied analysis of welding

International Nuclear Information System (INIS)

Turibus, S.N.; Caldas, F.C.M.; Miranda, D.M.; Monine, V.I.; Assis, J.T.

2010-01-01

This paper presents the analysis of residual stress introduced in welding process. As the stress in a material can induce damages, it is necessary to have a method to identify this residual stress state. For this it was used the non-destructive X-ray diffraction technique to analyze two plates from A36 steel jointed by metal inert gas (MIG) welding. The stress measurements were made by the sin 2 ψ method in weld region of steel plates including analysis of longitudinal and transverse residual stresses in fusion zone, heat affected zone (HAZ) and base metal. To determine the stress distribution along the depth of the welded material it was used removing of superficial layers made by electropolishing. (author)

Comparative study of residual stress by table of coordinates and X-ray diffraction in a welded joint

International Nuclear Information System (INIS)

Siqueira Filho, A.V.; Rolim, T.L.; Yadava, Y.P.; Ferreira, R.A.S.; Guimaraes, P.B.

2010-01-01

Residual stresses in a welded joint of naval steel ASTM AH-32 was measured either by the displacements of referenced points with a coordinated table (CT) or by x-ray diffraction (X-DR) after welding. For all tests, the welding was performed by a certified welder in the SMAW process, using an AWS E 7018 G3 electrode. Before welding, small holes evenly spaced were made in the specimens to be mapped on a coordinated table (CT). After labeling, the specimens were submitted to the welding process and new measurements by (CT) to evaluate the displacements produced by the tensions generated. In parallel, residual stress were measured by DR-X for validation of this new measurement methodology. (author)

Inhibition of Weld Corrosion in Flowing Brines Containing Carbon Dioxide

OpenAIRE

Alawadhi, Khaled

2009-01-01

The aim of this research was to study the effectiveness of a typical oilfield corrosion inhibitor, which is considered to be a green inhibitor (non toxic to the environment) in controlling internal corrosion of welded X65 pipeline steel in brines saturated with carbon dioxide at one bar pressure, under dynamic flowing conditions, over a range of temperatures. Several experimental configurations were used ranging from a simple flat plate design to a novel rotating cylinder electrode, to all...

Experimental evaluation of residual stresses produced by plain dents in pipelines

Energy Technology Data Exchange (ETDEWEB)

Pascotto, Jorge [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil); Marques, Altino; Fonseca, Maria Cindra [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil)

2009-07-01

A dent means a permanent plastic deformation of the circular cross-section of the pipe. Dents are potentially danger for structural integrity of onshore and offshore pipelines, because it causes a local stress and strain concentration. It is also expected that residual stresses are introduced by the non-uniform plastic deformation. A plain dent is a dent which causes a smooth change in the curvature of the pipe wall that contains no wall thickness reductions (such as a gouge or a crack) or other defects or imperfections (such as a weld). This work presents an experimental evaluation of residual stresses intensification due to plain dents introduced through the same indentation process, in samples made of the same steel line pipe, commonly used in the pipeline industry. The residual stresses were measured in the longitudinal and circumferential directions in preselected points by X-ray diffraction technique, before indentation. After the samples have been dented, the residual stresses were measured once more at the same points, for comparison. All samples presented a similar behavior of the residual stresses due to induced plain dents, and the X-ray diffraction technique shows itself as an efficient methodology of stress measurement in pipelines. (author)

Increase in the efficiency of radiographic inspection of welded joints for quality

International Nuclear Information System (INIS)

Feoktistov, V.A.; Polevik, V.A.; Korneev, V.A.

1982-01-01

The possibility of increasing the efficiency of radiographical inspection of metallic structures and pipelines welded joints for quality when mounting NPP equipment at the expense of a shorter exposure time is studied. The radiographic control has been conducted with X-ray RUP type instruments and ''Gammarid-25'' defectoscope. The exposure time is shown to be reduced when using active developers for processing radiograms. The sensitivity of radiographical images to X-ray and gamma-radiation increases when using D-82, D-72 active developers and ''roentgen-2'' standard developer for photochemical treatment

New method for NPP sodium coolant pipeline austenization

International Nuclear Information System (INIS)

Malashonok, V.A.; Rotshtejn, A.V.; Gotshalk, A.L.; Miryushchenko, E.F.

1980-01-01

Heat treatment technology is considered for pipelines intended for the NPP cooling systems employing sodium coolant. Various techniques are discussed which are used for protecting the pipeline internal surfaces against oxidation in the process of heat treatment. It is noted that the austenite formation of welded joints of steel 12Kh18N9 and steel Kh16N11M3 at temperatures of 1050 and 1100 deg C releases welding-induced stresses and reduces a possibility of local damages. Evacuation down to 1 mm Hg appears to be the most rational protective technique. The considered procedure of the pipeline heat treatment has been utilized for mounting the equipment of the BN-600 reactor at the Beloyarskaya NPP. The economic gain resulting from the use of the procedure, owing to decrease in argon consumption and reduction of labour input, makes up 150 000 roubles

Welded repair joints of boiler steels following operation in creep conditions exceeding the design time of operation

Energy Technology Data Exchange (ETDEWEB)

Dobrzanski, J.; Paszkowska, H.; Zielinski, A. [Institute for Ferrous Metallurgy, Gliwice (Poland)

2010-07-01

The assessment of suitability for further operation for materials and welded repair joints of thick-walled main steam pipeline components, made of steel 14MoV63, as well as steam superheater outlet headers made of steel X20CrMoV121 following operation in creep conditions in time periods considerably longer than the specified calculated time of operation. Strength properties, impact strength and transition temperature into brittle condition, as well as structure condition have been evaluated. On the basis of shortened creep tests, the residual life and disposable residual life of materials and welded joints have been determined. Material properties following operation and those of fabricated circumferential welded repair joints have been compared. The condition of examined components and suitability of the fabricated welded repair joints for further operation have been assessed. (orig.)

Twin-Wire Pulsed Tandem Gas Metal Arc Welding of API X80 Steel Linepipe

Directory of Open Access Journals (Sweden)

Wenhao Wu

2018-01-01

Full Text Available Twin-Wire Pulsed Tandem Gas Metal Arc Welding process with high welding production efficiency was used to join the girth weld seam of API X80 steel linepipe of 18.4 mm wall thickness and 1422 mm diameter. The macrostructure, microstructure, hardness, and electrochemical corrosion behavior of welded joints were studied. Effects of temperature and Cl− concentration on the corrosion behavior of base metal and weld metal were investigated. Results show that the welded joint has good morphology, mechanical properties, and corrosion resistance. The corrosion resistance of both the base metal and the weld metal decreases with increasing temperature or Cl− concentration. In the solution with high Cl− concentration, the base metal and weld metal are more susceptible to pitting. The corrosion resistance of the weld metal is slightly lower than that of the base metal.

The effects of welded joint characteristics on its properties in HDPE thermal fusion welding

Science.gov (United States)

Dai, Hongbin; Peng, Jun

2017-05-01

In this paper, PE100 pipes with the diameter of 200 mm and the thickness of 11.9 mm were used as material. The welded joints were obtained in different welding pressures with the optimal welding temperature of 220∘C. Reheating process on the welded joints with the temperature of 130∘C was carried out. The joints exhibited X-type, and the cause of X-type joints was discussed. The temperature field in the forming process of welded joints was measured, and tensile and bending tests on welded joints were carried out. The fracture surface of welded joints was observed by scanning electron microscopy (SEM), and crystallinity calculation was taken by X-ray diffraction (XRD). The mechanism of X-type weld profile effects on welded joints properties was analyzed. It was concluded that the mechanical properties of welded joints decrease with the reduced X distance between lines.

Construction and assembly of pipelines using API 5L grade X80 tubes - considerations to be observed with high-strength steels; Construcao e montagem de dutos terrestres utilizando tubos API 5L Gr. X80

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Ailton C. de; Rabello, Jose Mauricio B. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

2005-07-01

The use of line pipes API 5L Grade X80, at the point of view of designer allows: reduction of wall thickness and pipe weight or increase of design pressure. In the pipeline construction point of view, the use of line pipes API 5L Grade X80 provide some advantages, however some difficulties must be expected in several stages of the construction and assembly. The implications in cost, productivity, inspection and integrity, with the application of these high resistance steels, complying with PETROBRAS Standard N - 464 Construcao, Montagem e Condicionamento de Dutos Terrestres (Rev. H - 2004 Dec) and the experience consolidated in pipelines construction abroad were presented. At the design stage, a comparison between pipelines designed using API 5L-X70 and API 5L-X80 was carried out approaching the aspects of variation of thickness, pressure design and design factor. An evaluation of the expected gains when choosing API 5L Grade X80 steels were done, regarding reduction of costs and pipe weight. Regarding API 5L-X80 pipe fabrication, the obtained results were reported, proving that this aspect was already overcome, showing the viability of its production in Brazil. Difficulties were detected regarding construction and assembly stage and showing the need of revision of PETROBRAS standard N-464. (author)

X-ray tomographic in-service testing of girth welds - The European project TomoWELD

International Nuclear Information System (INIS)

Ewert, Uwe; Redmer, Bernhard; Walter, David; Thiessenhusen, Kai-Uwe; Bellon, Carsten; Nicholson, P. Ian; Clarke, Alan; Finke-Haerkoenen, Klaus-Peter; Scharfschwerdt, Joerg W.; Rohde, Karsten

2015-01-01

The new standard ISO 17636-2: 2013 'NDT of welded joints - Radiographic testing - Part 2: X- and gamma radiographic testing with digital detectors ''defines the testing practice for digital radiography of welds for the production and in-service inspection. Furthermore the DIN 25435-7:2014 ''In-service inspections of the components of the primary circuit of light water reactors - Part 7: Radiographic testing'' was published. The essential requirements are discussed. The new TomoWELD system can both perform measurements according to these standards as well as record tomographic cross-sectional images (equivalent to metallographic sections), to determine image sizes. Areas of application are chemical and nuclear facilities. It provides a fast testing of girth welds as compared to the use of film or imaging plates. In 2006 the mechanized planar tomography system, TomoCAR, was already introduced, with one could measure cross-sectional images. TomoWELD uses a new photon counting and energy resolving detector with CdTe-CMOS crystal hybrids. The new detector allows the choice of energy thresholds, and enables the reduction of the influence of scattered radiation on the radiographic images and the reconstructed cross-sectional images. An optimized irradiation geometry with a new manipulator design and a fast GPU-based reconstruction algorithm can be used to accelerate the reconstruction and to improve the reconstruction results. The size and the shape of planar and voluminous irregularities can be determined. The concept and the first pictures will be presented. (Contains mainly PowerPoint slides). [de

Analysis of Welding Joint on Handling High Level Waste-Glass Canister

International Nuclear Information System (INIS)

Herlan Martono; Aisyah; Wati

2007-01-01

The analysis of welding joint of stainless steel austenitic AISI 304 for canister material has been studied. At the handling of waste-glass canister from melter below to interim storage, there is a step of welding of canister lid. Welding quality must be kept in a good condition, in order there is no gas out pass welding pores and canister be able to lift by crane. Two part of stainless steel plate in dimension (200 x 125 x 3) mm was jointed by welding. Welding was conducted by TIG machine with protection gas is argon. Electric current were conducted for welding were 70, 80, 90, 100, 110, 120, 130, and 140 A. Welded plates were cut with dimension according to JIS 3121 standard for tensile strength test. Hardness test in welding zone, HAZ, and plate were conducted by Vickers. Analysis of microstructure by optic microscope. The increasing of electric current at the welding, increasing of tensile strength of welding yields. The best quality welding yields using electric current was 110 A. At the welding with electric current more than 110 A, the electric current influence towards plate quality, so that decreasing of stainless steel plate quality and breaking at the plate. Tensile strength of stainless steel plate welding yields in requirement conditions according to application in canister transportation is 0.24 kg/mm 2 . (author)

Canadian pipeline contractors in holding pattern

Energy Technology Data Exchange (ETDEWEB)

Caron, G [Pe Ben Pipelines Ltd.; Osadchuk, V; Sharp, M; Stabback, J G

1979-05-21

A discussion of papers presented at a Pipe Line Contractors Association of Canada convention includes comments by G. Caron (Pe Ben Pipelines Ltd.) on the continued slack in big-inch pipeline construction into 1980 owing mainly to delayed U.S. and Canadian decisions on outstanding Alaska Highway gas pipeline issues and associated gas export bids and on the use of automatic welding for expeditious construction of the northern sections of the Alaska Highway pipeline; by V. Osadchuk (Majestic Wiley Contract. Ltd.) on the liquidation of surplus construction equipment because of these delays; by M. Sharp (Can. North. Pipeline Agency) on the need for close U.S. and Canadian governmental and industrial cooperation to permit an early 1980 start for construction of the prebuild sections of the Alaska pipeline; and by J. G. Stabback (Can. Natl. Energy Board) on the Alaska oil pipeline applications by Foothills Pipe Lines Ltd., Trans Mountain Pipe Line Co. Ltd., and Kitimat Pipe Line Ltd.

Characterization of Mechanical Properties and Residual Stress in API 5L X80 Steel Welded Joints

Science.gov (United States)

de Sousa Lins, Amilton; de Souza, Luís Felipe Guimarães; Fonseca, Maria Cindra

2018-01-01

The use of high-strength and low-alloy steels, high design factors and increasingly stringent safety requirements have increased the operating pressure levels and, consequently, the need for further studies to avoid and prevent premature pipe failure. To evaluate the possibility of improving productivity in manual arc welding of this type of steel, this work characterizes the mechanical properties and residual stresses in API 5L X80 steel welded joints using the SMAW and FCAW processes. The residual stresses were analyzed using x-ray diffraction with the sin2 ψ method at the top and root of the welded joints in the longitudinal and transverse directions of the weld bead. The mechanical properties of the welded joints by both processes were characterized in terms of tensile strength, impact toughness and Vickers microhardness in the welded and shot peening conditions. A predominantly compressive residual stress was found, and shot peening increased the tensile strength and impact toughness in both welded joints.

Fatigue life evaluation of a cracked pipeline pipe operating under variable; Estudo da vida em fadiga com variacao de pressao interna em tubos com defeitos

Energy Technology Data Exchange (ETDEWEB)

Betanzos, J.; Mattei, F. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil); Strohaecker, T. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Programa de Pos-graduacao em Engenharia de Minas, Metalurgia e Materiais; Marinho, R.; Hoppe, R.; Donato, G. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

2005-07-01

Fatigue cracks in welded joints are commonly found in gas and oil pipelines and usually pumping is interrupted for repair. The strength of welded joints with defects, and consequently, the useful life of a pipeline, is an important information that could lead to great improvements in the reliability. To evaluate the working conditions determined by standards, specimens with 22'' diameter and 1/2'' wall thickness API 5L X60 pipes were used. Two semi-elliptical cracks were electro spark machined, with 50% and 25% of the tube wall thickness depths and a length/depth ratio of 1/20. Both defects were located in the HAZ of the tube longitudinal seam weld. Applying a cyclic internal pressure it was possible to propagate a fatigue crack until a through-thickness condition. The results show that the pressures to initiate crack propagation are too much higher than the pressures allowed by the standards for this kind of defect. (author)

Blanket Cooling Plates Mock-ups Manufactured in different Diffusion Weld Setup

International Nuclear Information System (INIS)

Von Der Weth, A.; Aktaa, J.

2007-01-01

Full text of publication follows: The breeding blanket box is considered as one of the most important components of a future fusion power plant. It will be assembled by so called cooling plates (CP) with a system of internal cooling channels. Such a CP is produced by two symmetric half pieces with half milled-in channels. Both pieces will be joined by a diffusion weld (DW) process. Within recent years a two step DW process for different EUROFER batches has been developed. It has been first applied to small laboratory scaled samples with dimensions of 25 mm x 30 mm x 40 mm. Then the DW process had then been successfully transferred to so called compact mock ups which are small CPs with dimensions of 67 mm x 70 mm x 50 mm. As third step this process has been used to manufacture a CP (465 mm x 205 mm x 50 mm) of a breeder unit in an industrial uniaxial diffusion weld setup. This paper treats the manufacturing sequence of a cooling plate and a first wall mock up in an industrial hot isostatic pressing (HIP) setup. The firstly laboratory specimens scaled diffusion weld process has been adjusted to different cooling channel dimensions and a different DW setup. The weld quality is investigated by tensile and Charpy impact testing. This allows comparison of the weld quality of mock ups welded in different DW setups. (authors)

Historical case - welding on service in Brazil Bolivia gas pipeline at 92 Bar of pressure, in Tres Lagoas, Mato Grosso do Sul, Brazil; Caso historico: execucao de soldagem em operacao no gasoduto Bolivia-Brasil a pressao de 92 BAR, em Tres Lagoas, Mato Grosso do Sul, Brasil

Energy Technology Data Exchange (ETDEWEB)

Vasconcellos, Carlos Renato Aragonez de [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil)]|[PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Lobao Filho, Jesualdo Pereira [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil); Alcatrao, Mauro dos Santos [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

2003-07-01

The Bolivia-Brazil Natural Gas Pipeline - GASBOL - begins in the city of Santa Cruz of La Sierra, in Bolivia, arriving in Canoas (RS), in Brazil, traveling an extension of 3.150 km. TBG is the owner and operator from 2.593 km in Brazilian soil, with maximum nominal diameter 32 inches, capacity of transportations until 30 million cubic meter a day, and MAOP 100 bar. This work presents the steps for the qualification the welding procedure and the jobs for the welding in service at 92 bar of pressure, the measures to guarantee the integrity of the gas pipeline, including lines support, requirements for hydrostatic testing and the main equipment used during the jobs. It is made reference to an accident happened several month after in service welding in gas pipeline and presents the respective cause. (author)

Numerical simulation of X90 UOE pipe forming process

Science.gov (United States)

Zou, Tianxia; Ren, Qiang; Peng, Yinghong; Li, Dayong; Tang, Ding; Han, Jianzeng; Li, Xinwen; Wang, Xiaoxiu

2013-12-01

The UOE process is an important technique to manufacture large-diameter welding pipes which are increasingly applied in oil pipelines and offshore platforms. The forming process of UOE mainly consists of five successive operations: crimping, U-forming, O-forming, welding and mechanical expansion, through which a blank is formed into a pipe in a UOE pipe mill. The blank with an appropriate edge bevel is bent into a cylindrical shape by crimping (C-forming), U-forming and O-forming successively. After the O-forming, there is an open-seam between two ends of the plate. Then, the blank is welded by automatic four-electrode submerged arc welding technique. Subsequently, the welded pipe is expanded with a mechanical expander to get a high precision circular shape. The multiple operations in the UOE mill make it difficult to control the quality of the formed pipe. Therefore, process design mainly relies on experience in practical production. In this study, the UOE forming of an API X90 pipe is studied by using finite element simulation. The mechanical properties tests are performed on the API X90 pipeline steel blank. A two-dimensional finite element model under the hypothesis of plane strain condition is developed to simulate the UOE process according to data coming from the workshop. A kinematic hardening model is used in the simulation to take the Bauschinger effect into account. The deformation characteristics of the blank during the forming processes are analyzed. The simulation results show a significant coherence in the geometric configurations comparing with the practical manufacturing.

ADVANCED INTEGRATION OF MULTI-SCALE MECHANICS AND WELDING PROCESS SIMULATION IN WELD INTEGRITY ASSESSMENT

Energy Technology Data Exchange (ETDEWEB)

Wilkowski, Gery M.; Rudland, David L.; Shim, Do-Jun; Brust, Frederick W.; Babu, Sundarsanam

2008-06-30

The potential to save trillions of BTU’s in energy usage and billions of dollars in cost on an annual basis based on use of higher strength steel in major oil and gas transmission pipeline construction is a compelling opportunity recognized by both the US Department of Energy (DOE). The use of high-strength steels (X100) is expected to result in energy savings across the spectrum, from manufacturing the pipe to transportation and fabrication, including welding of line pipe. Elementary examples of energy savings include more the 25 trillion BTUs saved annually based on lower energy costs to produce the thinner-walled high-strength steel pipe, with the potential for the US part of the Alaskan pipeline alone saving more than 7 trillion BTU in production and much more in transportation and assembling. Annual production, maintenance and installation of just US domestic transmission pipeline is likely to save 5 to 10 times this amount based on current planned and anticipated expansions of oil and gas lines in North America. Among the most important conclusions from these studies were: • While computational weld models to predict residual stress and distortions are well-established and accurate, related microstructure models need improvement. • Fracture Initiation Transition Temperature (FITT) Master Curve properly predicts surface-cracked pipe brittle-to-ductile initiation temperature. It has value in developing Codes and Standards to better correlate full-scale behavior from either CTOD or Charpy test results with the proper temperature shifts from the FITT master curve method. • For stress-based flaw evaluation criteria, the new circumferentially cracked pipe limit-load solution in the 2007 API 1104 Appendix A approach is overly conservative by a factor of 4/π, which has additional implications. . • For strain-based design of girth weld defects, the hoop stress effect is the most significant parameter impacting CTOD-driving force and can increase the crack

Creep strength of hastelloy X TIG-welded cylinder under internal pressure at elevated temperature

International Nuclear Information System (INIS)

Udoguchi, Teruyoshi; Indo, Hirosato; Isomura, Kazuyuki; Kobatake, Kiyokazu; Nakanishi, Tsuneo.

1981-01-01

Creep tests on circumferentially TIG-welded Hastelloy x cylinders were carried out under internal pressure for the investigation of structural behavior of welded components in high temperature environment. The creep rupture strength of TIG-welded cylinders was much lower than that of non-welded cylinders, while such reduction was not found in uniaxial creep tests on TIG-welded bars. It was deduced that the reduction was due to the low ductility (ranging from 1 to 5%) of the weld metal to which enhanced creep was induced by the adjacent base metal whose creep strain rate was much higher than that of the weld metal. Therefore, uniaxial creep tests on bar specimens is not sufficient for proper assessment of the creep rupture strength of welded components. Both creep strain rate and creep ductility should be concerned for the assessment. Creep tests by using components such as cylinder under internal pressure are recommendable for the confirmation of creep strength of welded structures and components. (author)

Comparing weld inspection codes: radiography vs. ultrasonics

International Nuclear Information System (INIS)

Moles, M.; Ginzel, E.

2007-01-01

Requirements for weld quality are continually increasing. This is due to a combination of factors: increased public awareness; bigger legal penalties; improved and thinner steels; better analysis techniques such as Engineering Critical Assessment (ECA); higher material costs. Weld quality is primarily dictated by construction codes, which should reflect the needs of society and industry: safety, the environment, society, and cost-effectiveness. As R and D produces new products, techniques and procedures, ideally these developments should be reflected in the codes. While pressure vessel and structural welding are certainly included here, it is really pipeline weld inspections that are setting the pace on new developments. For pipelines, a major shift was made from radiography to ultrasonics in Alberta some decades ago. This was driven by the 'need for speed', plus the requirement to size defects in the vertical plane for ECA (also called Fracture Mechanics or Fitness-For-Purpose). One of the main objectives of ECA was to benefit from the calculated fracture toughness of materials, and not to rely on the overly conservative workmanship criteria in radiography. In practice, performing repairs on higher quality material often does more harm than good; changing the microstructure can seriously compromise the material properties. Rising steel costs are another major driving force, so higher strength, thinner materials are being used. Under these conditions, ECA and defect sizing are critical. This paper compares where the various North American codes for pipelines, pressure vessels and structural welds stand on using advanced inspection techniques: ultrasonics, phased arrays, ECA, sizing techniques. For those codes which are not using the latest technologies, there are typical routes for incorporating them. (author)

78 FR 41829 - Pipeline Safety: Information Collection Activities, Revision to Annual Report for Hazardous...

Science.gov (United States)

2013-07-11

... following stakeholders: American Petroleum Institute (API) Association of Oil Pipelines (AOPL) This 30-day..., replacement of a weld or welding to fill in an anomaly, and removal of stress concentrators through grinding...

Shear punch testing as a tool for evaluating welded pipeline steel

Energy Technology Data Exchange (ETDEWEB)

Stewart, G.R.; Elwazri, A.; Varano, R.; Yue, S.; Jonas, J.J. [McGill Univ., Montreal, PQ (Canada). Dept. of Metals and Materials Engineering; Pokutylowicz, N. [ExxonMobil Research and Engineering Co., Annandale, NJ (United States)

2005-07-01

This study examined the mechanical properties across a welded joint in a 35 mm steel pipe. Results were compared with microhardness measurements. The chemical composition of the 4130 steel and welding wire included carbon, manganese, silicon, nickel, chromium and molybdenum. The thermal cycles experienced during welding can result in differences in the grain size, phase, composition and morphology of precipitates. These thermal cycles can upset the balance of high strength and good toughness in steels, producing poor toughness in the heat-affected zone (HAZ). In the shear punch test, a flat-ended cylindrical punch was used to produce a 3 mm diameter disk from a sheet specimen with a recommended thickness of 300 to 350 {mu}m. The shear punch test provided tensile property data with only a very small amount of material, which is ideal for testing welds. It also provides full tensile data (yield strength, ultimate tensile strength and elongation) which are not specifically provided by hardness testing. Shear punch techniques can also improve the across-weld resolution of tensile testing. The results showed that the changes in strength properties across the weld were consistent with the microhardness measurements. The change in elongation across the weld joint was successfully measured using the punch test method. The HAZ in the welded joint in this study had a good combination of high strength and ductility, while the weld bead had moderate strength and relatively low ductility. 7 refs., 1 tab., 9 figs.

Recommendations on X80 steel for the design of hydrogen gas transmission pipelines

International Nuclear Information System (INIS)

Briottet, L.; Batisse, R.; De Dinechin, G.; Langlois, P.; Thiers, L.

2012-01-01

By limiting the pipes thickness necessary to sustain high pressure, high-strength steels could prove economically relevant for transmitting large gas quantities in pipelines on long distance. Up to now, the existing hydrogen pipelines have used lower-strength steels to avoid any hydrogen embrittlement. The CATHY-GDF project, funded by the French National Agency for Research, explored the ability of an industrial X80 grade for the transmission of pressurized hydrogen gas in large diameter pipelines. This project has developed experimental facilities to test the material under hydrogen gas pressure. Indeed, tensile, toughness, crack propagation and disc rupture tests have been performed. From these results, the effect of hydrogen pressure on the size of some critical defects has been analyzed allowing proposing some recommendations on the design of X80 pipe for hydrogen transport. Cost of Hydrogen transport could be several times higher than natural gas one for a given energy amount. Moreover, building hydrogen pipeline using high grade steels could induce a 10 to 40% cost benefit instead of using low grade steels, despite their lower hydrogen susceptibility. (authors)

Failure analysis of natural gas buried X65 steel pipeline under deflection load using finite element method

International Nuclear Information System (INIS)

Liu, P.F.; Zheng, J.Y.; Zhang, B.J.; Shi, P.

2010-01-01

A 3D parametric finite element model of the pipeline and soil is established using finite element method to perform the failure analysis of natural gas buried X65 steel pipeline under deflection load. The pipeline is assumed to be loaded in a parabolic deflection displacement along the axial direction. Based on the true stress-strain constitutive relationship of X65 steel, the elastic-plastic finite element analysis employs the arc-length algorithm and non-linear stabilization algorithm respectively to simulate the strain softening properties of pipeline after plastic collapse. Besides, effects of the soil types and model sizes on the maximum deflection displacement of pipeline are investigated. The proposed finite element method serves as a base available for the safety design and evaluation as well as engineering acceptance criterion for the failure of pipeline due to deflection.

Pipeline technology. Petroleum oil - long-distance pipelines. Pipelinetechnik. Mineraloelfernleitungen

Energy Technology Data Exchange (ETDEWEB)

Krass, W; Kittel, A; Uhde, A

1979-01-01

All questions and concerns of pipeline technique are dealt with in detail. Some chapters can be applied for petroleum pipelines only or partly, for example the importance of petroleum pipelines, projecting, calculation, and operation. The sections of pipes and formings, laying, rights of way, and corrosion protection, accessories and remote effect technique, however, are of general interest, for example also for gas pipelines. In the chapter on working material, a very good summary of today's pipe working material including the thermomechanically treated steels is given. Besides methods of improving the toughness, the problems of the corrosion caused by strain cracking and the ways of avoiding it are pointed out. The pipe producing methods and, in the end of the chapter, the tests in the factory are explained. The section of laying deals with the laying methods being applied for years in pipeline construction, a big part referring to welding methods and tests. Active and passive corrosion protection are explained with all details. In addition to the solidity calculation presented with special regard to concerns of petroleum pipelines, theoretical fundaments and calculation methods for pressure are dealt with. Beside general questions of pumps, accessories, and drives, there is a section dealing with measurement and control techniques. Furthermore, remote effect and transmission techniques and news systems are explained in detail. Here, problems are referred to which are applicable not only to the operation of mineral oil pipelines. The book is completed by indications as to pipeline operation emphasizing general operation control, maintenance, repair methods and damage and their elimination. The last chapter contains a collection of the legal fundaments and the technical rules.

Effect of Inhibitors on Weld Corrosion under Sweet Conditions Using Flow Channel

OpenAIRE

Khaled Alawadhi; Abdulkareem Aloraier; Suraj Joshi; Jalal Alsarraf

2014-01-01

The aim of this paper is to compare the effectiveness and electrochemical behavior of typical oilfield corrosion inhibitors with previous oilfield corrosion inhibitors under the same electrochemical techniques to control preferential weld corrosion of X65 pipeline steel in artificial seawater saturated with carbon dioxide at a pressure of one bar. A secondary aim is to investigate the conditions under which current reversal takes place. A flow channel apparatus was used in the laboratory to s...

Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

OpenAIRE

Abdullah, Arman; Yahaya, Nordin; Md Noor, Norhazilan; Mohd Rasol, Rosilawati

2014-01-01

Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were i...

Study of API 5L X70 steel corrosion processes when in contact with some Brazilian soils; Estudo dos processos de corrosao de acos API 5L X70 em contato com alguns dos solos do Brasil

Energy Technology Data Exchange (ETDEWEB)

Jesus, Sergio Luis de

2007-07-01

Pipelines, fuel storage tanks and other metallic structures are in permanent contact and exposed to different types of soils, of horizons or layers, or of soil aggressiveness. This interaction may cause expressive damages to the environment and to the planned work. Contamination may occur due to leakage of stored products, splitting during transportation, accidents caused by pipelines without extensive maintenance. The result of these accidents could be, among others, some financial losses. In order to recognize the dynamic interactions between metallic surfaces and the environment it is crucial to have preventive actions and to develop better-applied materials. API steel 5L X70 has been used in structures of low and high pressure with high mechanical strength and corrosion and, even so, it is susceptible to etching corrosion since it is in contact with different environments from mangrove regions to industrial environments. The present case evaluated the role of 5L X70 API steel in contact with different soil horizons representative of the Brazilian soil. This investigation correlated chemical species with solute ions in soil solution, secondary and primary phase minerals besides physical and chemical characteristics as pH, electric conductivity, total dissolved solids, among others, to the results of corrosion resistance and ways of corrosion. The evaluation was carried out using x-ray diffractometry, scanning electron microscopy, total reflection x-ray fluorescence, fuel injection flow besides texture and gravimetric analyses to soil characterization and mineralogy, identification of corrosion products, soil solution analyses, evaluation of tested materials and classification of ways and types of corrosion. This was an attempt to integrate the data to a better understanding of the process involving reagents and products. The results showed that different soil horizons such as different types of analyzed soils produce specific etching in metallic structures

Butt Welding of 2205/X65 Bimetallic Sheet and Study on the Inhomogeneity of the Properties of the Welded Joint

Science.gov (United States)

Gou, Ning-Nian; Zhang, Jian-Xun; Wang, Jian-Long; Bi, Zong-Yue

2017-04-01

The explosively welded 2205 duplex stainless steel/X65 pipe steel bimetallic sheets were butt jointed by multilayer and multi-pass welding (gas tungsten arc welding for the flyer and gas metal arc welding for the transition and parent layers of the bimetallic sheets). The microstructure and mechanical properties of the welded joint were investigated. The results showed that in the thickness direction, microstructure and mechanical properties of the welded joint exhibited obvious inhomogeneity. The microstructures of parent filler layers consisted of acicular ferrite, widmanstatten ferrite, and a small amount of blocky ferrite. The microstructure of the transition layer and flyer layer consisted of both austenite and ferrite structures; however, the transition layer of weld had a higher volume fraction of austenite. The results of the microhardness test showed that in both weld metal (WM) and heat-affected zone (HAZ) of the parent filler layers, the average hardness decreased with the increasing (from parent filler layer 1 to parent filler layer 3) welding heat input. The results of hardness test also indicated that the hardness of the WM and the HAZ for the flyer and transition layers was equivalent. The tensile test combined with Digital Specklegram Processing Technology demonstrated that the fracturing of the welded joint started at the HAZ of the flyer, and then the fracture grew toward the base metal of the parent flyer near the parent HAZ. The stratified impact test at -5 °C showed that the WM and HAZ of the flyer exhibited lower impact toughness, and the fracture mode was ductile and brittle mixed fracture.

Fully mechanized welding of pipelines in the chemical industry and reactor construction

International Nuclear Information System (INIS)

Born, K.

1984-01-01

Pipes are increasingly being used as a construction element involving a growing demand for modern welding technology. The pulsed-arc welding procedures occupy an important position in mechanized pipe welding especially where flanged joints are to be made on turning pipes with a burner fixed in place. When the construction prohibits the turning of pipes, the orbital welding technique may be used. The paper discusses the question how the economic efficiency of TIG in inert-gas welding, which is the commonly used welding technique, could be enhanced and in how far other pulsed-arc welding methods, e.g. plasma keyhole or MIG/MAG pulsed-arc could be used in future. This could be done using the new possibilities offered by modern power sources and process technology. (orig.) [de

Effect of yield stress matching on ductile fracture behavior of girth welds for X line pipe

Energy Technology Data Exchange (ETDEWEB)

Motohashi, Hiroyuki; Hagiwara, Naoto [Tokyo Gas Co., Ltd. (Japan)

2005-07-01

This paper describes the effects of yield stress matching on the ductile fracture behavior of girth welded joints for X linepipes. Three welded joints were made on an X line pipe using several consumables to obtain about a 20% overmatched, even matched and about a 20% under matched weld metal. For these three welded joints, curved wide plate tensile tests were then conducted with a surface notch in the weld metal. To determine the ductile crack initiation from the surface notch, these tests employed a direct-current electric potential (d-c E P) method. Crack opening displacement, gauge length strain and local strain adjacent to the surface notch were also measured. The ductile crack initiation was successfully detected using the d-c E P method. The yield stress matching significantly affected the ductile crack initiation and fracture behavior, that is, the overmatched welded joint had a higher resistance to ductile fracture than that of the under matched welded joint. The allowable strength matching level was determined from the relationship between the strength matching and the gauge length strain at the ductile crack initiation detected using the d-c E P method. (author)

Development of Heat-Affected Zone Hardness Limits for In-Service Welding

Science.gov (United States)

2009-09-29

Welding onto in-service pipelines is frequently required to facilitate a repair or to install a branch connection using the "hot tapping" technique. Welds made in-service cool at an accelerated rate as the result of the ability of the flowing content...

The coupled effects of thickness and delamination on cracking resistance of X70 pipeline steel

International Nuclear Information System (INIS)

Guo, W.; Dong, H.; Lu, M.; Zhao, X.

2002-01-01

The effects of thickness and delamination on the fracture toughness and stable crack growth behaviour of high-toughness pipeline steels were investigated experimentally by use of compact tension specimens with thicknesses of 3-15 mm cut from a 17 mm-thick wall pipe. Material resistance curves were generated based on the stress intensity factor (SIF) K and the J-integral. The critical SIF K c and the J-resistance curves are found to be independent of thickness as the delaminations near the crack tip within the material reduce the out-of-plane constraint in thicker specimens. Both fracture mechanism and mechanics analyses shown that the fracture behaviour of the steel is controlled by the strong-coupled effects of thickness and delaminations. With increasing thickness, the out-of-plane stress constraint increases and causes the inclusion separation, growth and coalescence to form delaminations of different sizes before the main crack initiates. The delaminations in turn, reduce the out-of-plane constraint and thus, the thickness effect upon fracture. The advantages and disadvantages of delaminations in a safety assessment of pipelines are also discussed based on three-dimensional fracture theory

Study of API 5L X70 steel corrosion processes when in contact with some Brazilian soils

International Nuclear Information System (INIS)

Jesus, Sergio Luis de

2007-01-01

Pipelines, fuel storage tanks and other metallic structures are in permanent contact and exposed to different types of soils, of horizons or layers, or of soil aggressiveness. This interaction may cause expressive damages to the environment and to the planned work. Contamination may occur due to leakage of stored products, splitting during transportation, accidents caused by pipelines without extensive maintenance. The result of these accidents could be, among others, some financial losses. In order to recognize the dynamic interactions between metallic surfaces and the environment it is crucial to have preventive actions and to develop better-applied materials. API steel 5L X70 has been used in structures of low and high pressure with high mechanical strength and corrosion and, even so, it is susceptible to etching corrosion since it is in contact with different environments from mangrove regions to industrial environments. The present case evaluated the role of 5L X70 API steel in contact with different soil horizons representative of the Brazilian soil. This investigation correlated chemical species with solute ions in soil solution, secondary and primary phase minerals besides physical and chemical characteristics as pH, electric conductivity, total dissolved solids, among others, to the results of corrosion resistance and ways of corrosion. The evaluation was carried out using x-ray diffractometry, scanning electron microscopy, total reflection x-ray fluorescence, fuel injection flow besides texture and gravimetric analyses to soil characterization and mineralogy, identification of corrosion products, soil solution analyses, evaluation of tested materials and classification of ways and types of corrosion. This was an attempt to integrate the data to a better understanding of the process involving reagents and products. The results showed that different soil horizons such as different types of analyzed soils produce specific etching in metallic structures

Effect of pre-deformation on the fatigue crack initiation life of X60 pipeline steel

International Nuclear Information System (INIS)

Zheng, M.; Luo, J.H.; Zhao, X.W.; Bai, Z.Q.; Wang, R.

2005-01-01

It is impossible to keep petroleum and natural gas transmission pipelines free from defects in the manufacturing, installation and servicing processes. The damage might endanger the safety of pipelines and even shorten their service life; gas or petroleum release due to defects may jeopardise the surrounding ecological environments with associated economic and life costs. Pre-tensile deformation of X60 steel is employed to experimentally simulate the influence of dents on the fatigue crack initiation life. The investigation indicates that the fatigue crack initiation life of pre-deformed X60 pipeline steel can be assessed by a previously proposed energetic approach. The threshold for crack initiation increases with the pre-deformation due to a strain hardening effect, while the fatigue resistant factor exhibits a maximum with pre-deformation owing to its special dependence on fracture strain and fracture strength. The result is expected to be beneficial to the understanding of the effect of damage on the safety of pipelines and fatigue life prediction

New application technology for 'in situ' pipeline protection using pigging techniques

Energy Technology Data Exchange (ETDEWEB)

Pretorius, Louis Charles [Corrocoat SA (PTY) Ltd., Durban (South Africa)

2005-07-01

Pigging of long pipelines is a technique for in situ (field) coating, creating seamless internal structural linings. Originally developed for cleaning pipes, the system was adapted to apply internal anti-corrosion protection to pipes using a thin epoxy layer, which had some problems in weld coverage, stress cracking, poor cold weather curing and the inability to fill pitting corrosion metal loss. New coating materials, revised application methods and modified pigging equipment have made it possible to apply in situ liquid film coatings up to 1 mm thick, as an internal corrosion barrier to pipes, in a single application (similar to continuous screeding) resulting in a bonded 'GRP pipe within a steel pipe'. The method can be used for new projects on fully welded pipe lines avoiding coating problems associated with flange joints and/or couplings, or for refurbishment of old pipelines, varying from 150-900 mm diameter, up to 12 km long. Pipes can be buried, submerged, continuously welded or flanged. Many different pipes, such as oil platform to shore based pipelines, can all be treated using this method. Thick film polymer pigging techniques create new possibilities for Engineers to extend the life of pipeline systems, with significant cost savings compared to replacement pipe. (author)

High temperature pipeline design

Energy Technology Data Exchange (ETDEWEB)

Greenslade, J.G. [Colt Engineering, Calgary, AB (Canada). Pipelines Dept.; Nixon, J.F. [Nixon Geotech Ltd., Calgary, AB (Canada); Dyck, D.W. [Stress Tech Engineering Inc., Calgary, AB (Canada)

2004-07-01

It is impractical to transport bitumen and heavy oil by pipelines at ambient temperature unless diluents are added to reduce the viscosity. A diluted bitumen pipeline is commonly referred to as a dilbit pipeline. The diluent routinely used is natural gas condensate. Since natural gas condensate is limited in supply, it must be recovered and reused at high cost. This paper presented an alternative to the use of diluent to reduce the viscosity of heavy oil or bitumen. The following two basic design issues for a hot bitumen (hotbit) pipeline were presented: (1) modelling the restart problem, and, (2) establishing the maximum practical operating temperature. The transient behaviour during restart of a high temperature pipeline carrying viscous fluids was modelled using the concept of flow capacity. Although the design conditions were hypothetical, they could be encountered in the Athabasca oilsands. It was shown that environmental disturbances occur when the fluid is cooled during shut down because the ground temperature near the pipeline rises. This can change growing conditions, even near deeply buried insulated pipelines. Axial thermal loads also constrain the design and operation of a buried pipeline as higher operating temperatures are considered. As such, strain based design provides the opportunity to design for higher operating temperature than allowable stress based design methods. Expansion loops can partially relieve the thermal stress at a given temperature. As the design temperature increase, there is a point at which above grade pipelines become attractive options, although the materials and welding procedures must be suitable for low temperature service. 3 refs., 1 tab., 10 figs.

Study of MA Effect on Yield Strength and Ductility of X80 Linepipe Steels Weld

Science.gov (United States)

Huda, Nazmul; Lazor, Robert; Gerlich, Adrian P.

2017-09-01

Multipass GMAW (Gas Metal Arc Welding) welding was used to join X80 linepipe materials using two weld metals of slightly different compositions. Welding wires with diameters of 0.984 and 0.909 mm were used while applying the same heat input in each pass. The slight difference in the wire diameters resulted in different HAZ microstructures. The microstructures in the doubly reheated HAZ of both welds were found to contain bainite-ferrite. However, etching also revealed a difference in martensite-austenite (MA) fraction in these reheated zones. The MA exhibited twice the hardness of ferrite when measured by nanoindentation. Tensile testing from the reheated zone of both welds revealed a difference in yield strength, tensile strength and elongation of the transverse weld specimens. In the reheated zone of weld A, (produced with a 0.984 mm wire) a higher fraction of MA was observed, which resulted in higher strength but lower elongation compared to weld B. The ductility of weld A was found severely impaired (to nearly half of weld B) due to formation of closely spaced voids around the MA, along with debonding of MA from the matrix, which occurs just above the yield stress.

Cathodic polarization as a mean to stabilize physical parameters of underground pipelines

International Nuclear Information System (INIS)

Skritskij, R.R.

1993-01-01

Possibilities of further utilization of old gas-pipelines are determined. The investigations conducted confirm the conclusions of the previous researches on the stabilizing and improving effect of cathode polarization on the physico-mechanical properties of gas pipeline steel. Efficient and constant electrochemical protection of gas pipelines with the expired or close to expiration life time stabilizers and improves the basic physicomechanical properties of pipeline steel: ultimate strength and yield point, relative stretching. The same refers to impact strength. Degradation of physico-mechanical properties of gas pipeline steel is observed only in the zone of the welded joint

Device for the automatic X-ray testing of welded joints of pipes

International Nuclear Information System (INIS)

Ries, K.; Hannoschieck, K.; Rozic, K.M.; Basler, G.

1979-01-01

The notification flows of the tested pipes determined by the ultrasonic inspection are transmitted to the X-ray film automatic charger in the X-ray test room. The roll table for the pipes from the ultrasonic inspection to the X-ray test room is provided with an arrangement for weld detection and tube lathe, so that the X-ray films can be set on the corresponding spot by means of a cantilever. (RW) [de

Same yet different : a comparison of pipeline industries in Canada and Australia

Energy Technology Data Exchange (ETDEWEB)

Jaques, S. [Egis Consulting (Australia)

2000-07-01

A comparative evaluation of the pipeline industries in Canada and Australia was presented. The two countries are very similar in geography, politics, native land issues and populations. This paper focused on the similarities with respect to the pipeline industry and the long-distance, cross-country gas transmission pipelines. It addressed issues regarding pipeline industry organization, historical aspects and the infrastructure in both countries. The design practices of each country were compared and contrasted with attention to how construction techniques are affected by the terrain, climate and water crossing in each country. The author discussed issues such as grade, trench, string pipe, weld pipe, coat welds, hydrostatic testing, lowering, backfill and clean up. The issue of remote location factors was also presented. The future opportunities for Canada lies in Arctic gas development. For Australia, future opportunities lie in the expansion of the infrastructure to include gas from PNG to Queensland. Another possible opportunity is the development of an offshore distribution system to Tasmania. The author also noted that the aging pipeline system in both Canada and Australia will require careful consideration with respect to corrosion. 18 refs., 2 tabs., 2 figs.

Self-propelled x-ray flaw detector

International Nuclear Information System (INIS)

Ershov, L.S.; Krasilnikov, S.B.; Lozovoi, L.N.; Losev, J.F.; Morgovsky, L.Y.; Pelix, E.A.; Khakimyanov, R.R.

1988-01-01

A self-propelled X-ray flaw detector for radiographic inspection of welded joints in pipelines comprises a carriage mounting a motor, a detector having two Geiger counters, a pulsed X-ray generator, and an exposure and carriage electronic control system. A memory unit in the control system has four storage elements containing information about the motion of the carriage. As the carriage moves in direction A, first one and then the other of the Geiger counters receives radiation from an isotope source positioned near a joint, and by means of logic circuitry in the control system, the information in the storage elements is modified to stop the carriage and to operate a timer to expose the weld. During exposure the X-rays may interfere with the information in the storage elements, but by means of a square-wave generator and the logic circuitry, the stored information is correctly reset in order to eliminate false operation of the memory unit. (author)

HAZ microstructure in joints made of X13CrMoCoVNbNB9-2-1 (PB2 steel welded with and without post-weld heat treatment

Directory of Open Access Journals (Sweden)

M. Łomozik

2016-07-01

Full Text Available The article presents the results of research butt welded joints made of X13CrMoCoVNbNB9-2-1 steel. The joints were welded with post-weld heat treatment PWHT and without PWHT, using the temper bead technique TBT. After welding the joint welded with PWHT underwent stress-relief annealing at 770 °C for 3 hours. The scope of structural tests included the microstructural examination of the coarse-grained heat affected zone (HAZ areas of the joints, the comparison of the morphology of these areas and the determination of carbide precipitate types of the coarse grain heat affected zone (CGHAZ of the joints welded with and without PWHT.

Automatic ultrasonic inspection of pipeline girth weldswith a corrosive resistant alloy (Cra) layer

International Nuclear Information System (INIS)

Ent, Jan Van Der; Portzgen, Niels; Findlay, Niele; Nupen, Oddbjorn; Endal, Geir; Forli, Olav

2007-01-01

There is very limited experience in the Offshore Pipeline industry regarding the Automated Ultrasonic Inspection of Austenitic Girth Welds with CRA layers. The AUT inspection technique to be used for Austenitic welds having CRA layers deviates from the standard approach, which is described within internationally available AUT inspection standards. Due to the coarse grain and anisotropic structure of the weld material, special designed ultrasonic probes and adapted AUT system inspection software were required for examination of the Nome Satellite CRA welds. The 'new' inspection approach was subject for qualification and validation in order to demonstrate that the proposed technique could fulfill stringent inspection requirements which are applicable for the reeling process. Experiences from former projects are difficult to find, since this was the first clad pipeline to be reeled. To determine the overall qualification program to be performed for the Nome Satellite project, reference has been made to the existing development experiences on CRA weld inspection from the Shell Bonga project. The available defect population was obtained out of real CRA pipeline production welds and were therefore of a naturally coarse. Representatives from Technip, Statoil and DNV performed an audit at RTD premises with the objective to draw up an inventory of the performed CRA qualification work and to judge whether this work could be used for the benefit of the Nome Satellite project. It has been concluded that the existing CRA qualification work could be used to complement the Nome Satellite scope of CRA qualification work. As a result the statistical uncertainties were reduced merging the both qualification program results (referenced qualification data and additional Nome Satellite Field qualification work)

Evaluated Plan Stress Of Weld In Pressure Tube Using X Ray Diffraction Technique

International Nuclear Information System (INIS)

Phan Trong Phuc; Nguyen Duc Thanh; Luu Anh Tuyen

2011-01-01

X ray diffraction is a fundamental technique measuring stress, this technique has determined crystal strain in materials, from that determined stress in materials. This paper presents study of evaluating plane stress of weld in pressure tube, using modern XRD apparatus: X Pert Pro. (author)

Characterisation of weldment hardness, impact energy and microstructure in API X65 steel

International Nuclear Information System (INIS)

Hashemi, S.H.; Mohammadyani, D.

2012-01-01

The variation of microstructure and mechanical properties in various sub-zones of double submerged arc welded line pipe steel of grade API X65 was investigated. Instrumented Charpy V-notch tests and Vickers hardness experiments were conducted on the fusion zone, base metal and heat affected zone of the weld joint in 14.3 mm thick, 1219 mm outside diameter spiral pipeline. The lowest impact energy and the highest hardness level (160J and 218 HV, respectively) were recorded in the fusion zone. The low energy and high hardness characteristics of the seam weld can be attributed to its cast microstructure and the presence of grain boundary phases (such as proeutectoid ferrite), confirmed by standard metallographic observation. Despite this, service requirements set by the API 5L industry code (minimum impact energy of 73J, maximum hard spots of 350 HV) were fulfilled by the tested steel. Highlights: ► Experimental study of API X65 steel microstructure. ► Analysis of the relationship between X65 steel microstructure and hardness. ► Analysis of the relationship between X65 steel microstructure and impact energy. ► Presentation of detailed technical information on DSA welding in spiral pipes.

Failure Assessment for the High-Strength Pipelines with Constant-Depth Circumferential Surface Cracks

OpenAIRE

X. Liu; Z. X. Lu; Y. Chen; Y. L. Sui; L. H. Dai

2018-01-01

In the oil and gas transportation system over long distance, application of high-strength pipeline steels can efficiently reduce construction and operation cost by increasing operational pressure and reducing the pipe wall thickness. Failure assessment is an important issue in the design, construction, and maintenance of the pipelines. The small circumferential surface cracks with constant depth in the welded pipelines are of practical interest. This work provides an engineering estimation pr...

Effects of cathodic protection on cracking of high-strength pipeline steels

Energy Technology Data Exchange (ETDEWEB)

Elboujdaini, M.; Revie, R. W.; Attard, M. [CANMET Materials Technology Laboratory, Ottawa, ON(Canada)], email: melboujd@nrcan.gc.ca

2010-07-01

Four strength levels of pipeline steels, ranging from X-70 to X-120, were compared to determine whether higher strength materials are more susceptible to hydrogen embrittlement under cathodic protection. Ductility was measured in a solution at four protection levels, going from no cathodic protection to 500 mV of overprotection. All four steels showed loss of ductility under cathodic protection. Under cathodic polarization, the loss of ductility increased with the strength of the steel and the activity of the potential. After slow-strain-rate experiments conducted in air and examination of fracture surfaces, it is concluded that application of cathodic potentials, cathodic overprotection, higher strength of steel, and exposure to aqueous solution are factors that decrease the ductility of steel. Hydrogen reduction seems to be an important factor in ductility reduction and fractures. Observations suggest that high-strength pipelines need better control of cathodic protection than lower-strength pipelines.

A method for visual inspection of welding by means of image processing of x-ray photograph

International Nuclear Information System (INIS)

Koshimizu, Hiroyasu; Yoshida, Tohru.

1983-01-01

Computer image processing is becoming a helpful tool even in industrial inspections. A computerized method for welding visual inspection is proposed in this paper. This method is based on computer image processing of X-ray photograph of welding, in which the appearance information of weldments such as shape of weld bead really exists. Structural patterns are extracted at first and seven computer measures for inspection are calculated using those patterns. Software system for visual inspection is constructed based on these seven measures. It was experimentally made clear that this system can provide a performance of more than 0.85 correlation to human visual inspection. As a result, the visual inspection by computer using X-ray photograph became a promising tool to realize objectivity and quantitativity of welding inspection. Additionally, the consistency of the system, the possibility to reduce computing costs, and so on are discussed to improve the proposed method. (author)

Northern pipelines : challenges and needs

Energy Technology Data Exchange (ETDEWEB)

Dean, D.; Brownie, D. [ProLog Canada Inc., Calgary, AB (Canada); Fafara, R. [TransCanada PipeLines Ltd., Calgary, AB (Canada)

2007-07-01

Working Group 10 presented experiences acquired from the operation of pipeline systems in a northern environment. There are currently 3 pipelines operating north of 60, notably the Shiha gas pipeline near Fort Liard, the Ikhil gas pipeline in Inuvik and the Norman Wells oil pipeline. Each has its unique commissioning, operating and maintenance challenges, as well as specific training and logistical support requirements for the use of in-line inspection tools and other forms of integrity assessment. The effectiveness of cathodic protection systems in a permafrost northern environment was also discussed. It was noted that the delay of the Mackenzie Gas Pipeline Project by two to three years due to joint regulatory review may lead to resource constraints for the project as well as competition for already scarce human resources. The issue of a potential timing conflict with the Alaskan Pipeline Project was also addressed as well as land use issues for routing of supply roads. Integrity monitoring and assessment issues were outlined with reference to pipe soil interaction monitoring in discontinuous permafrost; south facing denuded slope stability; base lining projects; and reclamation issues. It was noted that automatic welding and inspection will increase productivity, while reducing the need for manual labour. In response to anticipated training needs, companies are planning to involve and train Aboriginal labour and will provide camp living conditions that will attract labour. tabs., figs.

An investigation on mechanical properties of steel fibre reinforced for underwater welded joint

Science.gov (United States)

Navin, K.; Zakaria, M. S.; Zairi, S.

2017-09-01

Underwater pipelines are always exposed to water and have a high tendency to have corrosion especially on the welded joint. This research is about using fiber glass as steel fiber to coat the welded joint to determine the effectiveness in corrosion prevention of the welded joint. Number of coating is varied to determine the better number coating to coat the pipeline. Few samples were left without immersion in salt water and few samples are immersed into salt water with same salinity as sea water. The material sample is prepared in dog bone shape to enable to be used in Universal Tensile Machine (UTM). The material prepared is left immersed for recommended time and tested in Universal Tensile Machine. Upon analyzing the result, the result is used to determine the breakage point whether broken on the welded joint or different place and also the suitable number of coating to be used.

Research of Technological Properties of Steel X6CRNITI18-10 Welded Joints Exploited in Nitric Acid Medium

Directory of Open Access Journals (Sweden)

Gediminas Mikalauskas

2016-04-01

Full Text Available The repair of chemical industry equipments often requires to replace long time operated pipes or welded inserts with the simi-lar chemical composition. During the study the joints from corro-sion resistant steel X6CrNiTi18-10 were welded by manual metal arc welding with covered electrodes (MMA process 111 and tungsten inert gas welding (TIG process 141 at different welding parameters. The visual, radiographic, penetrant control and ferrite content analysis were carried out. The transverse tensile and bending samples were produced from welded samples; also the macroscopic and microscopic analyse were carried out.

Comparative study of residual stress by table of coordinates and X-ray diffraction in a welded joint; Estudo comparativo das tensoes residuais por mesa de coordenadas e DR-X numa junta soldada

Energy Technology Data Exchange (ETDEWEB)

Siqueira Filho, A.V.; Rolim, T.L.; Yadava, Y.P.; Ferreira, R.A.S., E-mail: anibal_siqueira@yahoo.com.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Mecanica; Cardoso, F.I.B. [Universidade de Pernambuco (POLI/UPE), Recife, PE (Brazil); Guimaraes, P.B. [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, Recife, PE (Brazil)

2010-07-01

Residual stresses in a welded joint of naval steel ASTM AH-32 was measured either by the displacements of referenced points with a coordinated table (CT) or by x-ray diffraction (X-DR) after welding. For all tests, the welding was performed by a certified welder in the SMAW process, using an AWS E 7018 G3 electrode. Before welding, small holes evenly spaced were made in the specimens to be mapped on a coordinated table (CT). After labeling, the specimens were submitted to the welding process and new measurements by (CT) to evaluate the displacements produced by the tensions generated. In parallel, residual stress were measured by DR-X for validation of this new measurement methodology. (author)

Quality assurance on the welding work during the assembly of Wendelstein 7-X

International Nuclear Information System (INIS)

Schroeder, Michael

2011-01-01

At the Max-Planck-Institut fuer Plasmaphysik (IPP) in Greifswald (Germany) the stellarator experiment W7-X is presently being assembled. During this assembly many different weld connections are made, which are very important for the proper functionality of the experiment. This concerns mainly the structural integrity and the leak tightness. The quality requirements for the weld seams are high (mainly class B according to DIN EN ISO 5817), because the complex machine must operate reliably for more than 15 years and the possibility of any repair or change of important components is very small. To guarantee a high quality of the welds they are submitted to different tests. The applied test methods are depending on the function of the weld, the wall thickness, the seam geometry, and the material. The main test methods are visual testing (VT), penetrant testing (PT), radiographic testing (RT), ultrasonic testing (UT), leak testing (LT), permeability testing and macros. The paper will describe the application of these test methods and show their need by examples of typical weld imperfections.

Evaluation of the strong performance of the circular welded pipe connections with corrosion defects

OpenAIRE

Tarayevskyi, O. S.

2013-01-01

The paper shows the results of experimental studies and the analysis of the impact of long service life of the main gas pipelines, as well as of natural concentrators of stresses on the physical and mechanical p roperties of welded joints of steel 17G1S. A methodology was developed and patterns of gas pipeline welded joint material failure at static and low-frequency loads were established, as well as impact of stress concentrators during prolonged use. Some aspects of the mechanism of pipeli...

X-ray fluorescence analysis of welding fume particles

International Nuclear Information System (INIS)

Carsey, T.P.

1982-01-01

A commercial standard filter set and two laboratory-made standard filter sets are compared via the analysis of generated welding fume samples by X-ray fluorescence. The latter standards are made by (1) hydrophobic-edge membrane filters spiked with prepared metal ion solutions, and (2) filters through which a dispersion of metal oxide powder in isopropanol has been drawn. The results are presented in table form. Precision (Pre) is the relative standard deviation of the six samples. Four main conclusions are enumerated

Causes of the cracks in the pipeline made of the 15HM steel

Directory of Open Access Journals (Sweden)

Słania J.

2017-03-01

Full Text Available Issues referring to cracks in the pipelines made of the 15HM steel are described. Metallographic specimen of welded joints are provided. The results of impact strength tests, hardness tests and static tensile tests are given. Tests results as well as direct and indirect causes of the pipeline cracks are shown.

Erosion Behaviour of API X100 Pipeline Steel at Various Impact Angles and Particle Speeds

Directory of Open Access Journals (Sweden)

Paul C. Okonkwo

2016-09-01

Full Text Available Erosion is the gradual removal of material due to solid particle impingement and results in a failure of pipeline materials. In this study, a series of erosion tests were carried out to investigate the influence of particle speed and impact angle on the erosion mechanism of API X100 pipeline steel. A dry erosion machine was used as the test equipment, while the particle speed ranged from 20 to 80 m/s and impact angles of 30° and 90° were used as test parameters. The eroded API X100 steel surface was characterized using scanning electron microscope (SEM and X-ray photoelectron spectroscopy (XPS. The weight loss and erosion rate were also investigated. The results showed that at a 90° impact angle, a ploughing mechanism was occurring on the tested specimens, while material removal through low-angle cutting was the dominant mechanism at lower impact angles. Embedment of alumina particles on the target steel surface, micro-cutting, and low-angle cutting were observed at low impact angles. Therefore, the scratches, cuttings, and severe ploughings observed on some failed oil and gas pipelines could be attributed to the erosion mechanism.

X-Ray diffraction technique applied to study of residual stresses after welding of duplex stainless steel plates

International Nuclear Information System (INIS)

Monin, Vladimir Ivanovitch; Assis, Joaquim Teixeira de; Lopes, Ricardo Tadeu; Turibus, Sergio Noleto; Payao Filho, Joao C.

2014-01-01

Duplex stainless steel is an example of composite material with approximately equal amounts of austenite and ferrite phases. Difference of physical and mechanical properties of component is additional factor that contributes appearance of residual stresses after welding of duplex steel plates. Measurements of stress distributions in weld region were made by X-ray diffraction method both in ferrite and austenite phases. Duplex Steel plates were joined by GTAW (Gas Tungsten Arc Welding) technology. There were studied longitudinal and transverse stress components in welded butt joint, in heat affected zone (HAZ) and in points of base metal 10 mm from the weld. Residual stresses measured in duplex steel plates jointed by welding are caused by temperature gradients between weld zone and base metal and by difference of thermal expansion coefficients of ferrite and austenite phases. Proposed analytical model allows evaluating of residual stress distribution over the cross section in the weld region. (author)

Computer-aided orbital welding reaches a new level of performance

International Nuclear Information System (INIS)

Galloway, J.G.; Maak, P.Y.Y.; McNabb, S.C.

1993-01-01

This article documents the development of a custom-built microprocessor controller which overcomes the major shortcomings of existing commercially available pipe welding systems. This unique control design effectively extends the one-knob-control concept of the power source industry to the control of a complete mechanized welding system. Magnatech, East Granby, Conn., a manufacturer of orbital welding equipment, will be commercializing this technology into its Pipeliner welding system in the near future. Ontario Hydro Research Div. purchased a commercial pipe welding system for both laboratory welding development and field trials. Its applications were targeted for pressure piping in both nuclear power and fossil fuel fired electricity generating plants. They demonstrated the feasibility of using a mechanized continuous wire welding process to weld the fill passes of carbon steel piping to stringent inspection standards of nuclear pressure piping. They also concluded that significant improvements to commercial pipe welding systems can be achieved through the use of microprocessor controls

Implementing an X-ray validation pipeline for the Protein Data Bank.

Science.gov (United States)

Gore, Swanand; Velankar, Sameer; Kleywegt, Gerard J

2012-04-01

There is an increasing realisation that the quality of the biomacromolecular structures deposited in the Protein Data Bank (PDB) archive needs to be assessed critically using established and powerful validation methods. The Worldwide Protein Data Bank (wwPDB) organization has convened several Validation Task Forces (VTFs) to advise on the methods and standards that should be used to validate all of the entries already in the PDB as well as all structures that will be deposited in the future. The recommendations of the X-ray VTF are currently being implemented in a software pipeline. Here, ongoing work on this pipeline is briefly described as well as ways in which validation-related information could be presented to users of structural data.

Controlled short-circuiting MIG-MAG welding process and procedures applied to the root pass in pipeline construction; Processo de soldagem MIG/MAG em curto-circuito controlado e procedimentos aplicados ao passe de raiz na construcao de linhas dutoviarias

Energy Technology Data Exchange (ETDEWEB)

Silva, Regis H.G. e; Gohr Junior, Raul; Weck, Leonardo W.A. [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Soldagem e Mecatronica (LABSOLDA)

2005-07-01

The work deals with the study and development of the Controlled Short-Circuiting MIG/MAG Welding Process (CCC) and procedures for the root pass on pipes, in pipelines construction. The developed process (CCC) consists in an semi-automatic slag free operation, yielding higher productivity than the Coated Electrode and TIG processes, with satisfactory properties on the root weld. The significant influence of the welding over the time schedule and construction cost makes the development of this technology attractive, in order to become available at low cost, enhancing the companies' competitiveness in the globalized oil sector. The developed system, a MIG/MAG variant, features the advantages of short-circuiting metal transfer and avoids its inconveniences (mainly with high CO{sub 2} content gases), enabling its use on pipes root welding. This is possible through current waveform control, providing process and weld pool stability. Procedures for the root pass were determined for each of the welding positions reached in thick walled pipes welding, with the CCC. Also, the low welder training time was notable. (author)

The effect of hot strip mill processing parameters and alloy addition on low temperature toughness of API-X70 steel

Energy Technology Data Exchange (ETDEWEB)

Ro, Kwang Seop; Al-Shammary, Saad; Al-Butairi, Adel A. [QA and PTS, SAUDI IRON and STEEL COMAPNY, Al-Jubail, (Saudi Arabia); Al-Hajeri, Khaled F. [Saudi Basic Industries Corporation, Jubail, (Saudi Arabia)

2010-07-01

The design of high strength steel grade is based on stringent specifications in terms of chemistry, mechanical properties and surface requirements. This study investigated the effect of alloy addition on low temperature toughness of API X70 pipeline steel. Seven different chemical compositions have been selected for experimental testing. Ni, Cr and Cu were added in various quantities to the tested material without deteriorating the phase transformation to acicular ferrite. A tensile test, Charpy impact test, DWTT pressed notch test and microstructural observations using optical microscope and SEM were carried out. Statistical analyses were done to identify the relationship between chemical composition and DWTT shear area. The following equation showed excellent agreement with the experimental test data: Pct Shear aero of DWTT (-10 degrees C) = 954 - 0.3*SRT + 0.5*TBT - 0.4*FRT + 0.04*CT - 306*C - 60*(Mn+Ni+Cu) + 38*(Mo+Cr) - 791*(Ti+Nb+V) - 4*MA. The results showed that it is possible to design high strength API X 70 steel grades with good DWTT toughness by using the statistical equation that was developed.

East, West German gas pipeline grids linked

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper reports that Ruhrgas AG, Essen, has started up the first large diameter gas pipeline linking the gas grids of former East and West Germany. Ruhrgas last month placed in service a 40 in., 70 km line at Vitzeroda, near Eisenach, linking a new Ruhrgas pipeline in Hesse state with a 330 km gas pipeline built last year in Thuringia and Saxony states by Erdgasversorgungs GmbH (EVG), Leipzig. The new link enables pipeline operator EVG to receive 70 bcf/year of western European gas via Ruhrgas, complementing the 35 bcf/year of gas coming from the Commonwealth of Independent States via Verbundnetz Gas AG (VNG), Leipzig

Analysis of 3D Planar Laminations in a Welded Section of API 5L X52 Applying the Finite Element Method

Directory of Open Access Journals (Sweden)

Martin. J. Fernández-Cueto

Full Text Available Abstract The mechanical behavior of API 5L X52 steel with planar type laminations was studied in the present work. Planar laminations were proposed in the base metal (BM, heat affected zone (HAZ and welding bead (WB. Three-dimensional finite element (FE models, kinematic hardening and mechanical properties for BM, HAZ, and WB were activated in the finite element program. The results showed that crack propagation corresponds to the direction of the main stress. For a crack length (2a of 10.01 mm, crack propagation may occur at the right crack tip towards the outer wall of the BM. For 2a of 15.12 mm, crack propagation was located on the right crack tip and propagates to the inner wall. For 2a of 17.12 mm, crack propagation was observed at the left crack tip and propagates to the outer wall in the BM. The results achieved by FEM agree when compared with real laminations in API 5L pipelines.

Papers of the annual welding conference

International Nuclear Information System (INIS)

1981-01-01

Interest will be mainly focussed on structural welding in the fields of vehicle, power generating plant, railway bridge, reactor, tank and pipeline construction as well as energy transmission, energy production and space travel. Also under discussion will be such topical subjects as health and safety and the use of welding robots in the automobile industry, both these topics bearing direct relation to one another, at it is the labour-saving and health aspects which take precedence in both areas and to which medical experts are making valuable contributions to an ever increasing extent. (orig./IHOE) [de

Reality check on girth weld defect acceptance criteria

Energy Technology Data Exchange (ETDEWEB)

Brust, Bud; Kalyanam, Suresh; Shim, Do-Jun; Wilkowski, Gery [Engineering Mechanics Corporation of Columbus, Columbus, OH, (United States)

2010-07-01

Girth weld defect tolerance criteria for pipeline construction has evolved with time. Recently, ERPG recommended a new Tier 2 girth weld defect acceptance criterion. This paper described the new development on girth weld defect acceptance criteria. The inherent conservatisms of alternative girth weld defect acceptance criteria from the 2007 API 1104 Appendix A, CSA Z662 Appendix K, are compared to those from the proposed EPRG Tier 2 criteria. It is found that the API and CSA codes have the same empirical limit-load criteria. As well, there are conservatisms in the proposed EPRG Tier 2. The results showed that there are various reasons why large amounts of conservatism in the allowable flaw lengths in the CSA Appendix K,2007 API 1104 Appendix A, and proposed EPRG Tier 2 girth weld defect criterion exist. Small conservatisms on failure stress can result in large conservatisms in flaw size.

Development of an API 5 L X 70 coil for the production of API pipes continuously welded by electric resistance; Desenvolvimento de bobina API 5 L X 70 para producao de tubos API soldados continuamente por resistencia eletrica

Energy Technology Data Exchange (ETDEWEB)

Lopes, Alexandre R; Cavalheiro, Benedito C [CONFAB Tubos S.A., Sao Caetano do Sul, SP (Brazil)

1998-07-01

The manufacturing of high strength ERW pipe, which applies the continuous forming process, is known to lead to a relevant economy in a productivity basis. The past few years shown a trend of changing on grade range, from the past X52 to the present X70. The manufacturing of the latter grades for coils are somehow difficult due to the high Bauschinger effect observed on ERW pipes with ferritic-perlitic microstructure, that results in pipes with yield strength much lower than in coils, as on limitations on rolling, where controlled rolling is not applied. In this work, acicular dispersed bainite was searched, in a way to reduce this effect after pipe forming. API 5L X70 coils, from USIMINAS, were processed including an intentional addition of Molybdenum in the range of 0.20%, together with Columbium and Vanadium (added as 0.050% average). (author)

In situ x-ray diffraction of an arc weld showing the phase transformations of Ti and Fe as a function of position in the weld performed at a synchrotron

International Nuclear Information System (INIS)

Wong, J.; Elmer, J.W.; Waide, P.A.

1994-01-01

The synchrotron x-ray source provides a unique opportunity to observe open-quotes in-situclose quotes processes. The formation of the open-quotes short-livedclose quotes intermediate species, Ta 2 C, during the combustion synthesis of TaC, has been observed and reported by monitoring the Bragg diffraction peaks of the reactants and products. Similarly, the synthesis of the ferroelectric material, BaTiO 3 , and subsequent phase transformation from cubic to tetragonal have also been investigated. These experiments would not have been possible without the high incident x-ray flux available at a synchrotron source. The physical and mechanical properties of a weld join are highly independent upon the thermal history of the weld. Factors such as grain size, which increases with annealing, influence the tensile strength of the weld. This work presents the results of an investigation of the phase changes in two materials, titanium and stainless steel, which occur during the welding process. 4 refs., 3 figs

Residual stress investigation of copper plate and canister EB-Welds Complementary Results

International Nuclear Information System (INIS)

Gripenberg, H.

2009-03-01

The residual stresses in copper as induced by EB-welding were studied by specimens where the weld had two configurations: either a linear or a circumferential weld. This report contains the residual stress measurements of two plates, containing linear welds, and the full-scale copper lid specimen to which a hollow cylinder section had been joined by a circumferential EB-weld. The residual stress state of the EB-welded copper specimens was investigated by X-ray diffraction (XRD), hole drilling (HD) ring core (RC) and contour method (CM). Three specimens, canister XK010 and plates X251 and X252, were subjected to a thorough study aiming at quantitative determination of the residual stress state in and around the EB-welds using XRD for surface and HD and RC for spatial stress analysis. The CM maps one stress component over a whole cross section. The surface residual stresses measured by XRD represent the machined condition of the copper material. The XRD study showed that the stress changes towards compression close to the weld in the hollow cylinder, which indicates shrinkage in the hoop direction. According to the same analogy, the shrinkage in the axial direction is much smaller. The HD measurements showed that the stress state in the base material is bi-axial and, in terms of von Mises stress, 50 MPa for the plates and 20 MPa for the cylinder part of the canister. The stress state in the EB-welds of all specimens differs clearly from the stress state in the base material being more tensile, with higher magnitudes of von Mises stress in the plate than in the canister welds. The HD and RC results were obtained using linear elastic theory. The RC measurements showed that the maximum principal stress in the BM is close to zero near the surface and it becomes slightly tensile, 10 MPa, deeper under the surface. Welding pushed the general stress state towards tension with the maximum principal stress reaching 50 MPa, deeper than 5 mm below the surface in the weld. The

Load bearing capacity of welded joints between dissimilar pipelines with unequal wall thickness

Energy Technology Data Exchange (ETDEWEB)

Beak, Jonghyun; Kim, Youngpyo; Kim, Woosik [Korea Gas Corporation, Suwon (Korea, Republic of)

2012-09-15

The behavior of the load bearing capacity of a pipeline with unequal wall thickness was evaluated using finite element analyses. Pipelines with a wall thickness ratio of 1.22-1.89 were adopted to investigate plastic collapse under tensile, internal pressure, or bending stress. A parametric study showed that the tensile strength and moment of a pipeline with a wall thickness ratio less than 1.5 were not influenced by the wall thickness ratio and taper angle; however, those of a pipeline with a wall thickness ratio more than 1.5 decreased considerably at a low taper angle. The failure pressure of a pipeline with unequal wall thickness was not influenced by the wall thickness ratio and taper angle.

Effects of C and Si on strain aging of strain-based API X60 pipeline steels

Science.gov (United States)

Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Lee, Byeong-Joo; Hong, Seung-Pyo; Kim, Young-Woon; Yoo, Jang Yong; Hwang, Byoungchul; Shin, Sang Yong

2017-05-01

Four types of strain-based API X60 pipeline steels were fabricated by varying the C and Si contents, and the effects of C and Si on strain aging were investigated. The 0.05 wt% C steels consisted mainly of polygonal ferrite (PF), whereas the 0.08 wt% C steels consisted of acicular ferrite (AF). The volume fraction of AF increased with increasing C content because C is an austenite stabilizer element. The volume fractions of bainitic ferrite (BF) of the 0.15 wt% Si steels were higher than those of the 0.25 wt% Si steels, whereas the volume fractions of the secondary phases were lower. From the tensile properties before and after the aging process of the strainbased API X60 pipeline steels, the yield strength increased and the uniform and total elongation decreased, which is the strain aging effect. The strain aging effect in the strain-based API X60 pipeline steels was minimized when the volume fraction of AF was increased and secondary phases were distributed uniformly. On the other hand, an excessively high C content formed fine precipitates, and the strain aging effect occurred because of the interactions among dislocations and fine precipitates.

Ultrasonic inspection of austenitic welds

International Nuclear Information System (INIS)

Baikie, B.L.; Wagg, A.R.; Whittle, M.J.; Yapp, D.

1976-01-01

Optical and X-ray metallography combined with ultrasonic testing by compression waves was used for inspection of stainless steel weld metal produced by three different welding techniques. X-ray diffraction showed that each weld possessed a characteristic fibre textured structure which was shown by optical microscopy to be parallel to columnar grain boundaries. Metallographic evidence suggested that the development of fibre texture is due to the mechanism of competitive growth. From observations made as a result of optical metallographic examination the orientation of the fibre axis could be predicted if the weld geometry and welding procedure were known. Ultrasonic velocity and attenuation measurements as a continuous function of grain orientation, made on cylinders machined from weld samples, showed that attenuation was strongly orientation dependent. It was concluded that the sensitivity of ultrasonic inspection to small defects is unlikely to be as high for austenitic welds as for ferritic even when transmission is improved by modifying the welding procedure to improve the ultrasonic transmission. (U.K.)

Three-dimensional visualization of material flow during friction stir welding by two pairs of X-ray transmission systems

International Nuclear Information System (INIS)

Morisada, Y.; Fujii, H.; Kawahito, Y.; Nakata, K.; Tanaka, M.

2011-01-01

Material flow during friction stir welding is crucial to obtaining sound joints. However, this phenomenon is still not fully understood despite many investigations and numerous models. In this study, the material flow is three-dimensionally visualized by X-ray radiography using a tiny spherical tungsten tracer. The movement of the tracer during the friction stir welding is observed by two pairs of X-ray transmission real-time imaging systems. The three-dimensional material flow is obtained by following the locus of the tracer.

Manufacturing and use of spiral welded pipes for high pressure service : state of the art

Energy Technology Data Exchange (ETDEWEB)

Knoop, F.M.; Sommer, B. [Salzgitter GroBrohre GmbH, Salzgitter (Germany)

2004-07-01

This paper provided details of an improved helical seam 2-step (HTS) manufacturing process used to produce spiral welded large diameter pipes for high pressure transmission pipelines. During the process, pipe forming is combined with continuous tack welding and internal and external submerged arc welding at separate welding stations. The pipe forming unit consists of a 3 roll bending system with an outside roller cage used to guarantee the roundness of the pipe. The converging strip edges of the pipe are joined using a continuous shielded arc tack weld. Tack welding is done automatically with a laser-guided weld head. Run-out angles are adjusted by an automatic gap control system. The formed and tack-welded pipes are then fed to computer-controlled welding stations for final welding, where each pipe is rotated with a precise screw-like motion. The same welding materials used for the helical seam are used for the skelp end welding. The process offers more precise root gap control, as well as improved pipe geometry. Use of the process has also increased production rates and improved weld stability. The dimensions of the spiral-weld pipes are adjustable so that any diameter can be produced from a base material of the same width. The pipes can also be coated externally with fusion-bonded epoxy or 3-layer polyethylene/polypropylene. It was concluded that the process is being further refined to support the use of HTS pipes in high-pressure pipelines. New nondestructive testing techniques used to assess the performance of the line pipes were presented, as well as the results from hot and cold bending tests, field weldability trials, and tests related to the safety of spiral pipes. 16 refs., 2 tabs., 12 figs.

Advances in solar cell welding technology

Energy Technology Data Exchange (ETDEWEB)

Chidester, L.G.; Lott, D.R.

1982-09-01

In addition to developing the rigid substrate welded conventional cell panels for an earlier U.S. flight program, LMSC recently demonstrated a welded lightweight array system using both 2 x 4 and 5.9 x 5.9 cm wraparound solar cells. This weld system uses infrared sensing of weld joint temperature at the cell contact metalization interface to precisely control weld energy on each joint. Modules fabricated using this weld control system survived lowearth-orbit simulated 5-year tests (over 30,000 cycles) without joint failure. The data from these specifically configured modules, printed circuit substrate with copper interconnect and dielectric wraparound solar cells, can be used as a basis for developing weld schedules for additional cell array panel types.

The development of a remote repair system for deep water pipelines

Energy Technology Data Exchange (ETDEWEB)

Frazer, Ian; Giles, John [Stolt Offshore MS Ltd., Aberdeen (United Kingdom)

2000-07-01

The ability to maintain a high level of flexibility within the contingency plans for sub sea pipeline repair is a critical issue normally achieved by basing the repair plans on diver intervention. This allows the pipeline operator flexibility to respond to particular repair situations as they occur, minimize up front planning and optimize the investment in repair equipment and stock. However for deep water pipelines all intervention must be performed by remote methods, which require the development of suitable equipment and more detailed repair procedures. This paper describes the development of a remotely operated pipeline repair system capable of working down to 3000 m and allowing a relatively high level of flexibility with minimum investment in repair stock. The repair system is based upon the Modular Advanced Tie-In System (MATIS) which has been successfully developed for the tie-in of deep water flow lines. The MATIS repair system is based on the use of standard flanges to replace a damaged section of pipe with a spool piece in a similar manner to a hyperbaric welded repair. Various repair scenarios are discussed in the paper together with the equipment and the procedures used to perform the repair. The paper will also discuss the other remote repair options such as hot tapping and friction stitch welding. (author)

Tensometry technique for X-ray diffraction in applied analysis of welding; Tensometria por tecnica de difracao de raios X aplicada na analise de soldagens

Energy Technology Data Exchange (ETDEWEB)

Turibus, S.N.; Caldas, F.C.M.; Miranda, D.M.; Monine, V.I.; Assis, J.T., E-mail: snturibus@iprj.uerj.b [Universidade do Estado do Rio de Janeiro (IPRJ/UERJ), Nova Friburgo, RJ (Brazil). Inst. Politecnico

2010-07-01

This paper presents the analysis of residual stress introduced in welding process. As the stress in a material can induce damages, it is necessary to have a method to identify this residual stress state. For this it was used the non-destructive X-ray diffraction technique to analyze two plates from A36 steel jointed by metal inert gas (MIG) welding. The stress measurements were made by the sin{sup 2{psi}} method in weld region of steel plates including analysis of longitudinal and transverse residual stresses in fusion zone, heat affected zone (HAZ) and base metal. To determine the stress distribution along the depth of the welded material it was used removing of superficial layers made by electropolishing. (author)

An Investigation of Aging Behaviour in Microalloyed Steel (X70) UOE Pipe

Science.gov (United States)

Wiskel, J. B.; Ma, J.; Ivey, D. G.; Henein, H.

Aging of microalloyed steel pipe can occur at relatively low temperatures associated with the pipe coating process and/or during long term storage or use. The aging phenomenon is primarily attributed to C diffusion to dislocations and subsequent pinning of these dislocations. Important factors in the aging process include time, temperature, chemical composition and plastic deformation (arising from the pipe forming process). The work presented in this paper uses a Box-Behnken experimental design to determine the effect of time, temperature, location in the UOE pipe (90° or 180° to the weld), position through the pipe wall thickness (ID, CL or OD) and the steel's C/Nb ratio (0.60, 1.25 and 1.80) on the change in yield strength of three (uncoated) X70 UOE pipes. Quantitative microstructure analysis is undertaken to determine the grain size and microconstituent fractions of the as-received pipe material. Quadratic equations and response surface(s) correlating the significant aging variables with changes in the longitudinal yield stress of the pipe are developed. Both through thickness position and the C/Nb ratio, followed by aging temperature, had the largest effect on the change in longitudinal yield strength.

Microstructure and properties of pipeline steel with a ferrite/martensite dual-phase microstructure

International Nuclear Information System (INIS)

Li Rutao; Zuo Xiurong; Hu Yueyue; Wang Zhenwei; Hu, Dingxu

2011-01-01

In order to satisfy the transportation of the crude oil and gas in severe environmental conditions, a ferrite/martensite dual-phase pipeline steel has been developed. After a forming process and double submerged arc welding, the microstructure of the base metal, heat affected zone and weld metal was characterized using scanning electron microscopy and transmission electron microscopy. The pipe showed good deformability and an excellent combination of high strength and toughness, which is suitable for a pipeline subjected to the progressive and abrupt ground movement. The base metal having a ferrite/martensite dual-phase microstructure exhibited excellent mechanical properties in terms of uniform elongation of 7.5%, yield ratio of 0.78, strain hardening exponent of 0.145, an impact energy of 286 J at - 10 deg. C and a shear area of 98% at 0 deg. C in the drop weight tear test. The tensile strength and impact energy of the weld metal didn't significantly reduce, because of the intragranularly nucleated acicular ferrites microstructure, leading to high strength and toughness in weld metal. The heat affected zone contained complete quenching zone and incomplete quenching zone, which exhibited excellent low temperature toughness of 239 J at - 10 deg. C. - Research Highlights: →The pipe with ferrite/martensite microstructure shows high deformability. →The base metal of the pipe consists of ferrite and martensite. →Heat affected zone shows excellent low temperature toughness. →Weld metal mainly consists of intragranularly nucleated acicular ferrites. →Weld metal shows excellent low temperature toughness and high strength.

Structural integrity and fatigue crack propagation life assessment of welded and weld-repaired structures

Science.gov (United States)

Alam, Mohammad Shah

2005-11-01

Structural integrity is the science and technology of the margin between safety and disaster. Proper evaluation of the structural integrity and fatigue life of any structure (aircraft, ship, railways, bridges, gas and oil transmission pipelines, etc.) is important to ensure the public safety, environmental protection, and economical consideration. Catastrophic failure of any structure can be avoided if structural integrity is assessed and necessary precaution is taken appropriately. Structural integrity includes tasks in many areas, such as structural analysis, failure analysis, nondestructive testing, corrosion, fatigue and creep analysis, metallurgy and materials, fracture mechanics, fatigue life assessment, welding metallurgy, development of repairing technologies, structural monitoring and instrumentation etc. In this research fatigue life assessment of welded and weld-repaired joints is studied both in numerically and experimentally. A new approach for the simulation of fatigue crack growth in two elastic materials has been developed and specifically, the concept has been applied to butt-welded joint in a straight plate and in tubular joints. In the proposed method, the formation of new surface is represented by an interface element based on the interface potential energy. This method overcomes the limitation of crack growth at an artificial rate of one element length per cycle. In this method the crack propagates only when the applied load reaches the critical bonding strength. The predicted results compares well with experimental results. The Gas Metal Arc welding processes has been simulated to predict post-weld distortion, residual stresses and development of restraining forces in a butt-welded joint. The effect of welding defects and bi-axial interaction of a circular porosity and a solidification crack on fatigue crack propagation life of butt-welded joints has also been investigated. After a weld has been repaired, the specimen was tested in a universal

Influence of old rectangular repair patches on the burst pressure of a gas pipeline

International Nuclear Information System (INIS)

Fazzini, Pablo Gabriel; Otegui, Jose Luis

2006-01-01

Seven full scale hydrostatic burst tests were carried out on pipes extracted from an API 5LX52 gas pipeline that contained rectangular and elliptical fillet welded patches and other repairs of different geometries. All breaks took place after widespread yielding. This analysis shows that the patches that generate greater risks are those that: (1) were attached to the pipeline at very low pressure (2) were placed to repair large defects (3) are rectangular, long in the direction of the pipe, and narrow (4) the quality of the weld is doubtful. Based on data reported by In Line Inspection (ILI), of the four conditions mentioned above, only the third can be assessed in order to quantify risks and to schedule replacements

Friction factor in smooth and rough gas pipelines. An experimental study

Energy Technology Data Exchange (ETDEWEB)

Sletfjerding, Elling

1999-01-01

Flow of high pressure natural gas in pipelines has been studied experimentally. Pipeline flow of natural gas is characterized by high Reynolds numbers due to the low viscosity and relatively high density of pressurized gas. Friction factor correlations for high Reynolds number flow in smooth and rough pipes were developed. To study the effect of wall roughness on pipe flow at high Reynolds numbers 8 test pipes with different wall roughness were fabricated. The wall roughness in 6 of the test pipes was varied by adding glass beads in an epoxy coating applied on the pipe wall. One test pipe was treated with a smooth epoxy coating and one was left untreated. The inner diameter of the test pipes was 150 mm. Measurements of the pressure drop in the pipes were made in a closed flow loop at line pressures of 25, 70, 95 and 120 bar. The Reynolds number of the flow was varied in the range 2-30 million. The wall roughness of the test pipes was measured with a stylus instrument. Correlations between the directly measured wall roughness and the friction factor at fully rough flow conditions were presented. To characterize the wall roughness of the test pipes a parameter combining a measure of the roughness height (R{sub q}) and the texture of the wall roughness was used. Due to the high Reynolds number of the flow, minute irregularities of the pipe wall had significant effect on the friction factor in the pipe. The measured wall roughness of the test pipes was in the range 1.4 < R{sub q} <31 (my)m. The flow experiments in test pipes was compared with data from operating pipelines in the North Sea. The offshore pipelines are coated with the same epoxy coating as used in the test pipes. The friction factor in coated offshore gas pipelines showed smooth behavior when the additional pressure drop due to welds were accounted for. The study of coated gas pipelines showed that the friction factor was significantly lower than predicted by standard correlations.

Effects of Pre-Strains on Failure Assessment Analysis to API 5L X65 Pipeline

International Nuclear Information System (INIS)

Baek, Jong Hyun; Kim, Young Pyo; Kim, Woo Sik; Seok, Chang Sung

2009-01-01

This paper prescribed the structural integrity of the API 5 L X6 5 pipeline subjected to tensile pre-strain. The effects of pre-strain on the mechanical properties of API 5 L X6 5 pipe were substantially investigated through a variety of the experimental procedures. Axial tensile pre-strain of 1.5, 5 and 10% was applied to plate-type tensile specimens cut from the pipe body prior to mechanical testing. Tensile test revealed that yield strength and tensile strength were increased with increasing tensile pre-strain. The increasing rate of the yield strength owing to the pre-strain is greater than that of the tensile strength. However, the pre-strain up to 5% had a little effect on the decreasing of the fracture toughness. The structural integrity of the API 5 L X6 5 pipeline subjected to large plastic deformation was evaluated through the fitness-for service code.

Hot ductility testing and weld simulation tests

International Nuclear Information System (INIS)

Weber, G.; Schick, M.

1999-01-01

The objective of the project was to enhance the insight into the causes of intergranular cracks detected in austenitic circumferential welds at BWR pipes. The susceptibility of a variety of austenitic pipe materials to hot cracking during welding and in-service intergranular crack corrosion was examined. The assumption was cracking in the root area of the HAZ of a multiple-layer weld. Hot-ductility tests and weld simulation tests specifically designed for the project were performed with the austenitic LWR pipe materials 1.4553 (X6 CrNiNb 18 10 S), 1.4550 (X10 CrNiNb 18 9), 1.4533 (X6 CrNiTi 18 9, two weld pools), and a non-stabilized TP 304 (X5 CrNi 18 10). (orig./CB) [de

A Statistical Study on the Effect of Hydrostatic Pressure on Metastable Pitting Corrosion of X70 Pipeline Steel.

Science.gov (United States)

Yang, Zixuan; Kan, Bo; Li, Jinxu; Qiao, Lijie; Volinsky, Alex A; Su, Yanjing

2017-11-14

Hydrostatic pressure effects on pitting initiation and propagation in X70 steel are investigated by evaluating metastable pitting probability using electrochemical methods and immersion corrosion tests in containing chlorine ion solution. Potentiodynamic tests indicated that hydrostatic pressure can decrease the breakdown potential and lead to a reduced transpassivity region. Metastable test results revealed that hydrostatic pressure can increase metastable pitting formation frequency and promote stabilization of metastable pitting growth. Electrochemical impedance spectroscopy (EIS) results indicate that Hydrostatic pressure decreases the charge transfer resistance and increases the dissolution rate within the cavities. Corrosion test results also indicated that pitting initiation and propagation are accelerated by hydrostatic pressure. Result validity was verified by evaluating metastable pitting to predict pitting corrosion resistance.

Some welding problems in the gas reinjection network at Hassi-Messaoud

Energy Technology Data Exchange (ETDEWEB)

Birette, J J; Lamau, H

1966-07-01

The pipeline network for the injection gas in the Hassi Messaoud Field covers about 50 sq km and consists of 6-in. and 8-in. pipe, maximum working pressure 476 atm. Considerations of safety and reliability, together with easy welding operations in the desert, dictated the choice of a carbon-manganese-silicon alloy steel for the pipe; the wall thickness was calculated considering the stresses in the various parts of the network. Special welding techniques has to be developed, in view of the extreme variations in ambient temperature. This also required close and continuous quality control of the welding operations. All joints were prefabricated and pre-tested. Automatic welding was used in the shop, but only manual welding in the field. The network has now been in operation for 2 years, without any troubles.

Quantification of Microtexture at Weld Nugget of Friction Stir-Welded Carbon Steel

Science.gov (United States)

Husain, Md M.; Sarkar, R.; Pal, T. K.; Ghosh, M.; Prabhu, N.

2017-05-01

Friction stir welding of C-Mn steel was carried out under 800-1400 rpm tool rotation. Tool traversing speed of 50 mm/min remained same for all joints. Effect of thermal state and deformation on texture and microstructure at weld nugget was investigated. Weld nugget consisted of ferrite + bainite/Widmanstatten ferrite with different matrix grain sizes depending on peak temperature. A texture around ( ϕ 2 = 0°, φ = 30°, ϕ 2 = 45°) was developed at weld nugget. Grain boundary misorientation at weld nugget indicated that continuous dynamic recrystallization influenced the development of fine equiaxed grain structure. Pole figures and orientation distribution function were used to determine crystallographic texture at weld nugget and base metal. Shear texture components D1, D2 and F were present at weld nugget. D1 shear texture was more prominent among all. Large number of high-angle grain boundaries ( 60-70%) was observed at weld nugget and was the resultant of accumulation of high amount of dislocation, followed by subgrain formation.

Residual stresses analysis of friction stir welding using one-way FSI simulation

International Nuclear Information System (INIS)

Kang, Sung Wook; Jang, Beom Seon; Song, Ha Cheol

2015-01-01

When certain mechanisms, such as plastic deformations and temperature gradients, occur and are released in a structure, stresses remain because of the shape of the structure and external constraints. These stresses are referred to as residual stresses. The base material locally expands during heating in the welding process. When the welding is completed and cooled to room temperature, the residual stresses are left at nearly the yield strength level. In the case of friction stir welding, the maximum temperature is 80% to 90% of the melting point of the materials. Thus, the residual stresses in the welding process are smaller than those in other fusion welding processes; these stresses have not been considered previously. However, friction stir welding residual stresses are sometimes measured at approximately 70% or above. These residual stresses significantly affect fatigue behavior and lifetime. The present study investigates the residual stress distributions in various welding conditions and shapes of friction stir welding. In addition, the asymmetric feature is considered in temperature and residual stress distribution. Heat transfer analysis is conducted using the commercial computational fluid dynamics program Fluent, and results are used in the finite element structural analysis with the ANSYS Multiphysics software. The calculated residual stresses are compared with experimental values using the X-ray diffraction method.

Analysis of the Corrosion Behavior of an A-TIG Welded SS 409 Weld Fusion Zone

Science.gov (United States)

Vidyarthy, R. S.; Dwivedi, D. K.

2017-11-01

AISI 409 (SS 409) ferritic stainless steel is generally used as the thick gauge section in freight train wagons, in ocean containers, and in sugar refinery equipment. Activating the flux tungsten inert gas (A-TIG) welding process can reduce the welding cost during fabrication of thick sections. However, corrosion behavior of the A-TIG weld fusion zone is a prime concern for this type of steel. In the present work, the effect of the A-TIG welding process parameters on the corrosion behavior of a weld fusion zone made of 8-mm-thick AISI 409 ferritic stainless-steel plate has been analyzed. Potentiodynamic polarization tests were performed to evaluate the corrosion behavior. The maximum corrosion potential ( E corr) was shown by the weld made using a welding current of 215 A, a welding speed of 95 mm/min, and a flux coating density of 0.81 mg/cm2. The minimum E corr was observed in the weld made using a welding current of 190 A, a welding speed of 120 mm/min, and a flux coating density of 1.40 mg/cm2. The current study also presents the inclusive microstructure-corrosion property relationships using the collective techniques of scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction.

X-Ray and Neutron Diffraction Measurements of Dislocation Density and Subgrain Size in a Friction-Stir-Welded Aluminum Alloy

International Nuclear Information System (INIS)

Woo, Wan Chuck; Ungar, Tomas; Feng, Zhili; Kenik, Edward A.; Clausen, B.

2009-01-01

The dislocation density and subgrain size were determined in the base material and friction-stir welds of 6061-T6 aluminum alloy. High-resolution X-ray diffraction measurement was performed in the base material. The result of the line profile analysis of the X-ray diffraction peak shows that the dislocation density is about 4.5 x 10 14 m -2 and the subgrain size is about 200 nm. Meanwhile, neutron diffraction measurements have been performed to observe the diffraction peaks during friction-stir welding (FSW). The deep penetration capability of the neutron enables us to measure the peaks from the midplane of the Al plate underneath the tool shoulder of the friction-stir welds. The peak broadening analysis result using the Williamson-Hall method shows the dislocation density of about 3.2 x 10 15 m -2 and subgrain size of about 160 nm. The significant increase of the dislocation density is likely due to the severe plastic deformation during FSW. This study provides an insight into understanding the transient behavior of the microstructure under severe thermomechanical deformation

Study of stress-strain state of pipeline under permafrost conditions

Science.gov (United States)

Tarasenko, A. A.; Redutinskiy, M. N.; Chepur, P. V.; Gruchenkova, A. A.

2018-05-01

In this paper, the dependences of the stress-strain state and subsidence of pipelines on the dimensions of the subsidence zone are obtained for the sizes of pipes that have become most widespread during the construction of main oil pipelines (530x10, 820x12, 1020x12, 1020x14, 1020x16, 1220x14, 1220x16, 1220x18 mm). True values of stresses in the pipeline wall, as well as the exact location of maximum stresses for the interval of subsidence zones from 5 to 60 meters, are determined. For this purpose, the authors developed a finite element model of the pipeline that takes into account the actual interaction of the pipeline with the subgrade and allows calculating the SSS of the structure for a variable subsidence zone. Based on the obtained dependences for the underground laying of oil pipelines in permafrost areas, it is proposed to artificially limit the zone of possible subsidence by separation supports from the soil with higher building properties and physical-mechanical parameters. This technical solution would significantly reduce costs when constructing new oil pipelines in permafrost areas.

Cold bending of 34'' OD API 5L X80 pipes; Curvamento a frio de tubos API 5L X80 de 34'' de diametro

Energy Technology Data Exchange (ETDEWEB)

Silva, Ronaldo; Moreira, Fabio A.; Chad, Luis; Fritz, Marcelo C. [TenarisConfab, Pindamonhangaba, SP (Brazil); Batista, Gilmar Z.; Hippert, Eduardo [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

2008-07-01

A key factor that demands special attention in the pipeline construction is the cold bending process, since 30 to 40% of the pipes use this process in the field. This study aimed to evaluate the X80 cold bending operational parameters, in order make viable the use of this process in the installation of future onshore pipelines. Three 34''OD x 0,750'' pipes were bended. The bending was conducted using a hydraulic equipment with application of equally spaced punches, recording the correspondent angles related to the elastic and plastic deformations in order to assess the spring-back effect and performing dimensional inspection. Samples from pipe and the weld were subjected to mechanical and metallographic tests. It was possible to obtain a 19 deg curve and 27D radius without presenting any evidence of wrinkles, out of roundness or any type of mechanical damage. After analysis, all criteria established from project specifications were complied, the mechanical tests performed allowed comparing pipe mechanical properties of straight and bended regions. The results of this study provide technical know how for future X80 onshore pipelines applications. (author)

Creep damage development in welded X20 and P91

Energy Technology Data Exchange (ETDEWEB)

Brett, Steve; Holmstrom, Stefan; Hald, John; Borg, Ulrik; Aakjaer Jensen, Soeren; Vulpen, Rijk Van; Degnan, Craig; Vinter Dahl, Kristian; Vilhelmsen, Tommy

2011-03-15

The Martensitic steel X20CrMoV121 (hereinafter called X20) and the modified 9Cr1Mo steel (hereinafter called P91) have been used for a number of years in high temperature applications since they posses superior creep strength compared to low alloyed steels. Due to the simple fact that very few failures were observed, almost no knowledge as to the evolution of creep damage in welds were available despite long operation times exceeding well over 100.000 hours. It has been suggested that X20 will develop creep damage in a different manner compared to low alloyed steel, i.e damage initiation should be slow followed by accelerated growth. The research work presented in this report included systematic investigations of the first components of X20, which has developed creep during long-term operation. All of the investigated components showed creep damage evolution similar to low alloy steels

Versatile Friction Stir Welding/Friction Plug Welding System

Science.gov (United States)

Carter, Robert

2006-01-01

A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

Critical defect size assessment in pipelines on a nuclear power plant

Directory of Open Access Journals (Sweden)

Dimova Galya

2018-01-01

Full Text Available In many energy industry structures, pipeline systems are subject to the impact of mechanical forces, moments of forces and fluid flows of high pressure and temperature. These load factors cause defects in the pipeline metal. As the years of operation increase, defects may occur and grow, which may lead to the destruction of pipeline walls. Special measures have been planned and implemented to ensure the safe operation of high-energy facilities. This study focused on pipelines and nozzles of nuclear power plant equipment with bimetal welded joints on which the size of critical defects was assessed. The base of assessment covers material properties, temperature and stress fields, fracture mechanics calculations. This study involves developing of finite element models and implementing simulations on them in order to obtain temperature fields and determine the stress-strain state of the component.

Induced AC voltages on pipelines may present a serious hazard

International Nuclear Information System (INIS)

Kirkpatrick, E.L.

1997-01-01

The problem of induced AC voltages on pipelines has always been with us. Early pipeline construction consisted of bare steel or cast iron pipe, which was very well grounded. Bell and spigot, mechanical, or dresser-style joint couplings often were used, creating electrically discontinuous pipelines which are less susceptible to AC induction. Although induced AC affects any pipeline parallel to a high-voltage alternating current (HVAC) power line, the effects were not noticeable on bare pipelines. With the advent of welded steel pipelines, modern cathodic protection (CP) methods and materials, and the vastly improved quality of protective coatings, induced AC effects on pipelines have become a significant consideration on many pipeline rights-of-way. In the last two to three decades, one has been seeing much more joint occupancy of the same right-of-way by one or more pipelines and power lines. As the cost of right-of-way and the difficulty in acquisition, particularly in urban areas, have risen, the concept of joint occupancy rights-of-way has become more attractive to many utility companies. Federal and state regulations usually insist on joint-use right-of-way when a utility proposes crossing regulated or publicly owned lands, wherever there is an existing easement. Such joint use allows the induced AC phenomena to occur and may create electrical hazards and interference to pipeline facilities. Underground pipelines are especially susceptible if they are well-coated and electrically isolated for CP

Influence of Post-Weld Heat Treatment on the Microstructure, Microhardness, and Toughness of a Weld Metal for Hot Bend

Directory of Open Access Journals (Sweden)

Xiu-Lin Han

2016-03-01

Full Text Available In this work, a weld metal in K65 pipeline steel pipe has been processed through self-designed post-weld heat treatments including reheating and tempering associated with hot bending. The microstructures and the corresponding toughness and microhardness of the weld metal subjected to the post-weld heat treatments have been investigated. Results show that with the increase in reheating temperature, austenite grain size increases and the main microstructures transition from fine polygonal ferrite (PF to granular bainitic ferrite (GB. The density of the high angle boundary decreases at higher reheating temperature, leading to a loss of impact toughness. Lots of martensite/austenite (M/A constituents are observed after reheating, and to a large extent transform into cementite after further tempering. At high reheating temperatures, the increased hardenability promotes the formation of large quantities of M/A constituents. After tempering, the cementite particles become denser and coarser, which considerably deteriorates the impact toughness. Additionally, microhardness has a good linear relation with the mean equivalent diameter of ferrite grain with a low boundary tolerance angle (2°−8°, which shows that the hardness is controlled by low misorientation grain boundaries for the weld metal.

Defect accumulation in welded joints of 12Kh1MF steel steam pipelines during creep

International Nuclear Information System (INIS)

Anokhov, A.E.; Alekhova, I.A.

1982-01-01

Technique for investigation of micropore accumulation in 12Kh1MF steel welded joints is proposed. The micropore density in different zones of welded joints in non-uniform. It is shown that failure localization in welded joint in the softening zone during the creep takes place due to the micropore priority accumulation in this zone. It is found out that accumulation of residual deformations in different zones of 12Kh1MF welded joints under creep runs more uniformly as the level of working stresses decreases and test duration increases

Quantification of Residual Stresses in External Attachment Welding Applications

DEFF Research Database (Denmark)

Alhajri, R.; Liu, S.; Yu, Z.

2017-01-01

welding (GMAW) process to deposit single beadonplate welds with ER70S6 wire on ASTM516 grade 70 pressure vessel steel plates of 6.3, 12.7, and 19 mm thicknesses. Microstructural analysis, temperature, and distortion measurements of weldments were performed to qualify the FEA modeling results. In addition...

Reliability of non-destructive test techniques in the inspection of pipelines used in the oil industry

International Nuclear Information System (INIS)

Carvalho, A.A.; Rebello, J.M.A.; Souza, M.P.V.; Sagrilo, L.V.S.; Soares, S.D.

2008-01-01

The aim of this work is to evaluate the reliability of non-destructive test (NDT) techniques for the inspection of pipeline welds employed in the petroleum industry. Radiography, manual and automatic ultrasonic techniques using pulse-echo and time of flight diffraction (TOFD) were employed. Three classes of defects were analyzed: lack of penetration (LP), lack of fusion (LF) and undercut (UC). The tests were carried out on specimen made from pipelines containing defects, which had been artificially inserted on laying the weld bead. The results showed the superiority of the automatic ultrasonic tests for defect detection compared with the manual ultrasonic and radiographic tests. Additionally, artificial neural networks (ANN) were used in the detection and automatic classification of the defects

Testing of quality of welded joints using heavy-current pulse X-ray apparatuses

International Nuclear Information System (INIS)

Gusev, E.A.; Firstov, V.G.

1988-01-01

The possibilities of carrying out of radiographic and electroradiographic testing of quality of welded joints using heavy-current pulse X-ray apparatuses under the mode of single pulses are shown. Basic quantitative characteristics of radiographic testing permitting to detect the focus distance, sensitivity behaviour and optical density of image are presented. Peculiarities of electroradiographic image formation under the mode of single pulses of nanosecond range are analysed. The outlook of heavy-current pulse X-ray apparatus application under the mode of single pulses in industry is estimated

EBSD study of hydrogen-induced cracking in API-5 L-X46 pipeline steel

International Nuclear Information System (INIS)

Venegas, V.; Caleyo, F.; Gonzalez, J.L.; Baudin, T.; Hallen, J.M.; Penelle, R.

2005-01-01

The spatial distribution of plastic deformation and grain orientation surrounding hydrogen-induced cracks (HIC) is investigated in samples of API-5L-X46 pipeline steel using scanning electron microscopy and electron backscattering diffraction (EBSD). This work shows direct experimental evidence of the influence of microstructure, microtexture and mesotexture on HIC crack path

Materials participation in welded joints manufacturing

Science.gov (United States)

Ghenghea, L. D.

2016-08-01

Management of materials dilution to form a joint with higher features asked by complex metallic structures is a problem that took attention and efforts of welding processes researchers and this communication will give a little contribution presenting some scientific and experimental results of dilution processes studied by Welding Research Group from Iasi, Romania, TCM Department. Liquid state welding processes have a strong dependence related to dilution of base and filler materials, the most important are for automatic joining using welding. The paper presents a review of some scientific works already published and their contributions, results of dilution coefficient evaluation using weighing, graphics and software applied for shielded metal arc welding process. Paper results could be used for welders’ qualification, welding procedure specification and other welding processes researchers’ activities. The results of Welding Research Group from Iasi, Romania, TCM Department, show dilution coefficient values between 20-30 % of base material and 70-80 % of filler material for studied welding process.

Methodic recommendations on ultrasonic testing of pipeline austenitic butt joints

International Nuclear Information System (INIS)

Grebennik, V.S.; Lantukh, V.M.; Tajts, M.Z.; Ermolov, I.N.; Volkov, A.S.; Vyatskov, I.A.; Kesler, N.A.; Shchedrin, I.F.

1989-01-01

Recommendations for the application of ultrasonic testing of austenitic welded joints of the Du 500 pipelines with the walls 32-34 mm thick made of steel Kh18N10T are developed. The optimal values of the main parameters of ultrasonic testing are determined experimentally. Principles of calculation of the optimal parameters are considered. 1 ref.; 4 figs

Corrosion behavior of API 5L-X80 Pipeline steel for natural gas pipeline

International Nuclear Information System (INIS)

Mohd Asyadi Azam Mohd Abid; Imai, Hachiro

2007-01-01

Natural energy problem, including the environmental aspects had changes into certain circumstances in recent years and natural gas has been a focus of constant attention from the viewpoint of energy efficiency and pollution free. From that kind of background, pipeline construction for petroleum and natural gas were considerate as energy infrastructure maintenance plan. Based on the clarification of Asian Pipeline Project (1997-2007) centered in Japan, international pipeline is needed as the natural gas is mainly transported from gas field in Russia and Middle East to consumer country such as Japan etc. It used in severe condition such as cold district and sea. In the meantime, pipeline steel is not just received damages by earth crust fluctuation and corrosion, but also suffered from the corrosion caused by anions that were dissolved in sea and groundwater. The diversification of dispersion and consumption structure of natural gas supply acceptance base are seen regarding, that made the needs of the storing are rising and dealt with the quantitative spatial expansion of the demand. By that, corrosion resistance, not only the hardness, tough, weldability, corrosiveness gas environment is extremely required. (author)

Correlation of Weld Appearance with Microstructure and Mechanical Properties of 2024-T4 Aluminum Alloy Welded by Fiber Laser with Filler Wire

Directory of Open Access Journals (Sweden)

XU Fei

2017-11-01

Full Text Available Two typical cross-section of welds, including nail shape and near X shape, are obtained in the process of fiber laser welding 2024-T4 Al alloy with filler wire. The correlations of the two weld appearances and other elements (such as microstructure, microhardness, and joint's tensile properties were analyzed. The results show that the weld with near X shape cross-section during the welding process is more stable than that with nail shape cross-section, and the welding spatter of the former is smaller than that of the latter. The microstructure of the weld zone is columnar grains and equiaxed grains, the columnar grains are formed near the fusion line and growing along the vertical direction of the fusion line, the equiaxed grains are distributed in the center of the weld zone. The secondary dendrite of the grains in the center of the weld with nail shape cross-section grows better, and gradually forms to equiaxed dendrite, while the grains size of the weld with near X shape cross-section is relatively finer, exhibiting equiaxed cellular grain. Compared with the joint with nail shape cross-section of the weld, the joint with near X shape cross-section of the weld have some different characteristics, the precipitation strengthening phase θ(Al2Cu content in weld zone of the latter is more than that of the former, the average microhardness value of the weld zone of the latter is higher than that of the former, the softening phenomenon of heat affect zone (HAZ of the latter is weaker than that of the former, and the joint's tensile strength and plasticity of the latter are lower than that of the former slightly.

Modern industrial devices of X-ray radioscopy and fluorography for nondestructive testing of welded joints

International Nuclear Information System (INIS)

Leonov, B.I.; Sosnin, F.R.; Luk'yanenko, Eh.A.; Veselovskij, L.N.; Kanter, B.M.; Zhdanov, A.V.

1984-01-01

Technical data on industrial X-ray television systems with new convertors are given. The convertors are characterized by high sensitivity, defect detectability, lower noise level as compared to earlier produced equipment. Flu uorographic installation for testing welded joints of thick metals is described

Recent development in low-constraint fracture toughness testing for structural integrity assessment of pipelines

Science.gov (United States)

Kang, Jidong; Gianetto, James A.; Tyson, William R.

2018-03-01

Fracture toughness measurement is an integral part of structural integrity assessment of pipelines. Traditionally, a single-edge-notched bend (SE(B)) specimen with a deep crack is recommended in many existing pipeline structural integrity assessment procedures. Such a test provides high constraint and therefore conservative fracture toughness results. However, for girth welds in service, defects are usually subjected to primarily tensile loading where the constraint is usually much lower than in the three-point bend case. Moreover, there is increasing use of strain-based design of pipelines that allows applied strains above yield. Low-constraint toughness tests represent more realistic loading conditions for girth weld defects, and the corresponding increased toughness can minimize unnecessary conservatism in assessments. In this review, we present recent developments in low-constraint fracture toughness testing, specifically using single-edgenotched tension specimens, SENT or SE(T). We focus our review on the test procedure development and automation, round-robin test results and some common concerns such as the effect of crack tip, crack size monitoring techniques, and testing at low temperatures. Examples are also given of the integration of fracture toughness data from SE(T) tests into structural integrity assessment.

Mechanical Characteristics of Submerged Arc Weldment in API Gas Pipeline Steel of Grade X65

International Nuclear Information System (INIS)

Hashemi, S. H.; Mohammadyani, D.

2011-01-01

The mechanical properties of submerged arc weldment (SAW) in gas transportation pipeline steel of grade API X65 (65 ksi yield strength) were investigated. This steel is produced by thermo mechanical control rolled (TMC), and is largely used in Iran gas piping systems and networks. The results from laboratory study on three different regions; i.e. base metal (BM), fusion zone (FZ) and heat affected zone (HAZ) were used to compare weldment mechanical characteristics with those specified by API 5L (revision 2004) standard code. Different laboratory experiments were conducted on test specimens taken from 48 inch outside diameter and 14.3 mm wall thickness gas pipeline. The test results showed a gradient of microstructure and Vickers hardness data from the centerline of FZ towards the unaffected MB. Similarly, lower Charpy absorbed energy (compared to BM) was observed in the FZ impact specimens. Despite this, the API specifications were fulfilled in three tested zones, ensuring pipeline structural integrity under working conditions.

Canadian pipeline transportation system : transportation assessment

International Nuclear Information System (INIS)

2009-07-01

In addition to regulating the construction and operation of 70,000 km of oil and natural gas pipelines in Canada, the National Energy Board (NEB) regulates the trade of natural gas, oil and natural gas liquids. This report provided an assessment of the Canadian hydrocarbon transportation system in relation to its ability to provide a robust energy infrastructure. Data was collected from NEB-regulated pipeline companies and a range of publicly available sources to determine if adequate pipeline capacity is in place to transport products to consumers. The NEB also used throughput and capacity information received from pipeline operators as well as members of the investment community. The study examined price differentials compared with firm service tolls for transportation paths, as well as capacity utilization on pipelines and the degree of apportionment on major oil pipelines. This review indicated that in general, the Canadian pipeline transportation system continues to work effectively, with adequate pipeline capacity in place to move products to consumers who need them. 9 tabs., 30 figs., 3 appendices.

Residual stress measurement of electron beam welded copper plates using prism hole drilling method

International Nuclear Information System (INIS)

Laakkonen, M.

2013-12-01

Eleven electron beam (EB) welded copper plates were measured in this investigation with Prism hole drilling equipment made by Stresstech Oy. All samples contained a linear weld in their center. Two different sets of plates were measured in this investigation. The first set included five samples (X436, X437, X438, X439 and X440) which were welded using four different welding speeds. Samples X439 and X440 were welded with the same speed but X440 is the only sample of the set that received a cosmetic pass. The second set received heat treatments at four different temperatures. Samples X456 and X458 were annealed at the same temperature but sample X456 received a cosmetic pass while X458 did not. Samples X455 and X457 were both annealed at a different temperature, with (X455) or without (X457) the cosmetic pass. Two areas were machined from the samples. About five millimeters was machined from the surfaces on the both of areas. Machined surfaces located on the top surfaces. The measurement points on the top surface are located on the weld and 20 mm and 120 mm from the weld on machined areas. Lower surface measurements are located -20 mm, 20 mm and 120 mm from the weld. All measurements were about 122 mm from the edges perpendicular to the weld. The top surfaces of all samples were machined in two areas across the weld. About 5 mm were removed. Stress measurements on the top surfaces were performed in these two areas, on the weld and 20 mm and 120 mm away from the weld. Stresses were also measured on the back sides, at -20 mm, 20 mm and 120 mm distance from the weld. All measurement locations were about 122mm from the sample edges. Most of the measurements give tensile strengths from 0 MPa to 30 MPa. Stresses parallel to the weld were slightly higher than weld stresses in transverse direction. The machined surfaces have residual stress values above 30 MPa near the surface. (orig.)

Residual stress measurement of electron beam welded copper plates using prism hole drilling method

Energy Technology Data Exchange (ETDEWEB)

Laakkonen, M. [Stresstech Oy, Jyvaeskylae (Finland)

2013-12-15

Eleven electron beam (EB) welded copper plates were measured in this investigation with Prism hole drilling equipment made by Stresstech Oy. All samples contained a linear weld in their center. Two different sets of plates were measured in this investigation. The first set included five samples (X436, X437, X438, X439 and X440) which were welded using four different welding speeds. Samples X439 and X440 were welded with the same speed but X440 is the only sample of the set that received a cosmetic pass. The second set received heat treatments at four different temperatures. Samples X456 and X458 were annealed at the same temperature but sample X456 received a cosmetic pass while X458 did not. Samples X455 and X457 were both annealed at a different temperature, with (X455) or without (X457) the cosmetic pass. Two areas were machined from the samples. About five millimeters was machined from the surfaces on the both of areas. Machined surfaces located on the top surfaces. The measurement points on the top surface are located on the weld and 20 mm and 120 mm from the weld on machined areas. Lower surface measurements are located -20 mm, 20 mm and 120 mm from the weld. All measurements were about 122 mm from the edges perpendicular to the weld. The top surfaces of all samples were machined in two areas across the weld. About 5 mm were removed. Stress measurements on the top surfaces were performed in these two areas, on the weld and 20 mm and 120 mm away from the weld. Stresses were also measured on the back sides, at -20 mm, 20 mm and 120 mm distance from the weld. All measurement locations were about 122mm from the sample edges. Most of the measurements give tensile strengths from 0 MPa to 30 MPa. Stresses parallel to the weld were slightly higher than weld stresses in transverse direction. The machined surfaces have residual stress values above 30 MPa near the surface. (orig.)

Re-weldability tests of irradiated 316L(N) stainless steel using laser welding technique

International Nuclear Information System (INIS)

Yamada, Hirokazu; Kawamura, Hiroshi; Tsuchiya, Kunihiko; Kalinin, George; Kohno, Wataru; Morishima, Yasuo

2002-01-01

SS316L(N)-IG is the candidate material for the in-vessel and ex-vessel components of fusion reactors such as ITER (International Thermonuclear Experimental Reactor). This paper describes a study on re-weldability of un-irradiated and/or irradiated SS316L(N)-IG and the effect of helium generation on the mechanical properties of the weld joint. The laser welding process is used for re-welding of the water cooling branch pipeline repairs. It is clarified that re-welding of SS316L(N)-IG irradiated up to about 0.2 dpa (3.3 appm He) can be carried out without a serious deterioration of tensile properties due to helium accumulation. Therefore, repair of the ITER blanket cooling pipes can be performed by the laser welding process

Re-weldability tests of irradiated 316L(N) stainless steel using laser welding technique

Science.gov (United States)

Yamada, Hirokazu; Kawamura, Hiroshi; Tsuchiya, Kunihiko; Kalinin, George; Kohno, Wataru; Morishima, Yasuo

2002-12-01

SS316L(N)-IG is the candidate material for the in-vessel and ex-vessel components of fusion reactors such as ITER (International Thermonuclear Experimental Reactor). This paper describes a study on re-weldability of un-irradiated and/or irradiated SS316L(N)-IG and the effect of helium generation on the mechanical properties of the weld joint. The laser welding process is used for re-welding of the water cooling branch pipeline repairs. It is clarified that re-welding of SS316L(N)-IG irradiated up to about 0.2 dpa (3.3 appm He) can be carried out without a serious deterioration of tensile properties due to helium accumulation. Therefore, repair of the ITER blanket cooling pipes can be performed by the laser welding process.

Transformation and Precipitation Reactions by Metal Active Gas Pulsed Welded Joints from X2CrNiMoN22-5-3 Duplex Stainless Steels.

Science.gov (United States)

Utu, Ion-Dragos; Mitelea, Ion; Urlan, Sorin Dumitru; Crăciunescu, Corneliu Marius

2016-07-21

The high alloying degree of Duplex stainless steels makes them susceptible to the formation of intermetallic phases during their exposure to high temperatures. Precipitation of these phases can lead to a decreasing of the corrosion resistance and sometimes of the toughness. Starting from the advantages of the synergic Metal Active Gas (MAG) pulsed welding process, this paper analyses the structure formation particularities of homogeneous welded joints from Duplex stainless steel. The effect of linear welding energy on the structure morphology of the welded joints was revealed by macro- and micrographic examinations, X-ray energy dispersion analyses, measurements of ferrite proportion and X-ray diffraction analysis. The results obtained showed that the transformation of ferrite into austenite is associated with the chromium, nickel, molybdenum and nitrogen distribution between these two phases and their redistribution degree is closely linked to the overall heat cycle of the welding process. The adequate control of the energy inserted in the welded components provides an optimal balance between the two microstructural constituents (Austenite and Ferrite) and avoids the formation of undesirable intermetallic phases.

Transformation and Precipitation Reactions by Metal Active Gas Pulsed Welded Joints from X2CrNiMoN22-5-3 Duplex Stainless Steels

Directory of Open Access Journals (Sweden)

Ion-Dragos Utu

2016-07-01

Full Text Available The high alloying degree of Duplex stainless steels makes them susceptible to the formation of intermetallic phases during their exposure to high temperatures. Precipitation of these phases can lead to a decreasing of the corrosion resistance and sometimes of the toughness. Starting from the advantages of the synergic Metal Active Gas (MAG pulsed welding process, this paper analyses the structure formation particularities of homogeneous welded joints from Duplex stainless steel. The effect of linear welding energy on the structure morphology of the welded joints was revealed by macro- and micrographic examinations, X-ray energy dispersion analyses, measurements of ferrite proportion and X-ray diffraction analysis. The results obtained showed that the transformation of ferrite into austenite is associated with the chromium, nickel, molybdenum and nitrogen distribution between these two phases and their redistribution degree is closely linked to the overall heat cycle of the welding process. The adequate control of the energy inserted in the welded components provides an optimal balance between the two microstructural constituents (Austenite and Ferrite and avoids the formation of undesirable intermetallic phases.

X-ray Radiographic Study of Simulated Voids-like Defects in Al-Castings and Welded in Steel

International Nuclear Information System (INIS)

Mahrok, M.; Juma, Th.; Saeed, F.

2013-01-01

the detection and evaluation of imperfections in internal structures of casting and welded joints by x - ray radiography were studied.Optimum radiography conditions that improved the radiographic detection were attempted.Mathematical equations for radiography were used to calculate the size and depth of defects in casting were tested for validity to a wide range of parameters commonly used in radiography and for variable density and shape of the defects with respect to surrounding.Two kinds of samples are prepared.The first is aluminum casting through which two different sizes of a regular steel spheres are included and then radio graphed from two opposite sides to estimate their dimensional information from the radiographs.The second sample is steel plates which are welded and then radio graphed by x - rays.Imperfections such as incomplete root penetration, undercut and porosity were detected in the radiographs.

X-ray evaluation of residual stress distributions within surface machined layer generated by surface machining and sequential welding

International Nuclear Information System (INIS)

Taniguchi, Yuu; Okano, Shigetaka; Mochizuki, Masahito

2017-01-01

The excessive tensile residual stress generated by welding after surface machining may be an important factor to cause stress corrosion cracking (SCC) in nuclear power plants. Therefore we need to understand and control the residual stress distribution appropriately. In this study, residual stress distributions within surface machined layer generated by surface machining and sequential welding were evaluated by X-ray diffraction method. Depth directional distributions were also investigated by electrolytic polishing. In addition, to consider the effect of work hardened layer on the residual stress distributions, we also measured full width at half maximum (FWHM) obtained from X-ray diffraction. Testing material was a low-carbon austenitic stainless steel type SUS316L. Test specimens were prepared by surface machining with different cutting conditions. Then, bead-on-plate welding under the same welding condition was carried out on the test specimens with different surface machined layer. As a result, the tensile residual stress generated by surface machining increased with increasing cutting speed and showed nearly uniform distributions on the surface. Furthermore, the tensile residual stress drastically decreased with increasing measurement depth within surface machined layer. Then, the residual stress approached 0 MPa after the compressive value showed. FWHM also decreased drastically with increasing measurement depth and almost constant value from a certain depth, which was almost equal regardless of the machining condition, within surface machined layer in all specimens. After welding, the transverse distribution of the longitudinal residual stress varied in the area apart from the weld center according to machining conditions and had a maximum value in heat affected zone. The magnitude of the maximum residual stress was almost equal regardless of the machining condition and decreased with increasing measurement depth within surface machined layer. Finally, the

Application of Phased Array Ultrasonic Testing (PAUT) on Single V-Butt Weld Integrity Determination

International Nuclear Information System (INIS)

Amry Amin Abas; Mohd Kamal Shah Shamsudin; Norhazleena Azaman

2015-01-01

Phased Array Ultrasonic Testing (PAUT) utilizes arrays of piezoelectric elements that are embedded in an epoxy base. The benefit of having such kind of array is that beam forming such as steering and focusing the beam front possible. This enables scanning patterns such as linear scan, sectorial scan and depth focusing scan to be performed. Ultrasonic phased array systems can potentially be employed in almost any test where conventional ultrasonic flaw detectors have traditionally been used. Weld inspection and crack detection are the most important applications, and these tests are done across a wide range of industries including aerospace, power generation, petrochemical, metal billet and tubular goods suppliers, pipeline construction and maintenance, structural metals, and general manufacturing. Phased arrays can also be effectively used to profile remaining wall thickness in corrosion survey applications. The benefits of PAUT are simplifying inspection of components of complex geometry, inspection of components with limited access, testing of welds with multiple angles from a single probe and increasing the probability of detection while improving signal-to-noise ratio. This paper compares the result of inspection on several specimens using PAUT as to digital radiography. The specimens are welded plates with single V-butt weld made of carbon steel. Digital radiography is done using blue imaging plate with x-ray source. PAUT is done using Olympus MX2 with 5 MHz probe consisting of 64 elements. The location, size and length of defect is compared. (author)

Characterization for solidification and phase transformations of pure-titanium steel weld metal with time-resolved X-ray diffraction system

International Nuclear Information System (INIS)

Terasaki, Hidenori; Komizo, Yu-ichi; Nishino, Fumihiro; Ikeda, Masahiko

2007-01-01

Understanding and controlling solidification and phase transformation process of weld metal is essential for forming the microstructure with superior mechanical property. Recent evolution of analysis technique makes for solidification and phase transformation process to be in-situ analyzed, in direct and reciprocal lattice space. In the present work, unidirectional-solidification and phase transformation in the weld metal of commercial pure-titanium in Gas Tungsten Arc welding was in-situ observed by using Time-Resolved X-Ray Diffraction system with two-dimensional pixel detector. An undulator beam was used as a probe. Larger diffraction area could be detected in the time-resolution of 0.05 seconds, in unidirectional solidification and subsequent phase transformation process of pure-titanium weld metal. Furthermore, the microstructure formation during β-α phase transformation was in situ observed with High temperature Laser Scanning Confocal Microscopy. The crystal configurations in unidirectional solidification of weld metal and rapid change of phase ratio in reconstructive phase transformation were clearly analyzed. (author)

Technology of application of pipe's arc of the integral pipeline in power plant 'Oslomej'

Directory of Open Access Journals (Sweden)

Cvetanoski Radomir

2017-01-01

Full Text Available Pipe connections allow interconnection of individual pipes to obtain pipeline and pipe connection with the equipment and their connection to the valve. The pipe connector should have the same strength of the pipe, impermeability and possibility of easy assembly and disassembly. Connecting of pipes of such construction is carried out by welding due to the work in conditions of maximum operating pressures and temperatures. The pipes can be joined at the ends. When welding the pipe lines should take into account the condition that the flow resistance of the fluid must to be as small as possible. Therefore, special preparation for pipe welding it is often necessary, as well as for the welding processes itself not to have any internal height differences of the joint or unevenness of the internal diameter of the pipe.

X-ray tomographic in-service testing of girth welds - The European project TomoWELD; Roentgen-tomographische In-Service-Pruefung von Rundschweissnaehten. Das Europaeische Projekt TomoWELD

Energy Technology Data Exchange (ETDEWEB)

Ewert, Uwe; Redmer, Bernhard; Walter, David; Thiessenhusen, Kai-Uwe; Bellon, Carsten [BAM Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany); Nicholson, P. Ian; Clarke, Alan [TWI Technology Centre, Port Talbot (United Kingdom); Finke-Haerkoenen, Klaus-Peter [Ajat Oy Ltd., Espoo (Finland); Scharfschwerdt, Joerg W.; Rohde, Karsten [AREVA GmbH, Erlangen (Germany)

2015-07-01

The new standard ISO 17636-2: 2013 'NDT of welded joints - Radiographic testing - Part 2: X- and gamma radiographic testing with digital detectors ''defines the testing practice for digital radiography of welds for the production and in-service inspection. Furthermore the DIN 25435-7:2014 ''In-service inspections of the components of the primary circuit of light water reactors - Part 7: Radiographic testing'' was published. The essential requirements are discussed. The new TomoWELD system can both perform measurements according to these standards as well as record tomographic cross-sectional images (equivalent to metallographic sections), to determine image sizes. Areas of application are chemical and nuclear facilities. It provides a fast testing of girth welds as compared to the use of film or imaging plates. In 2006 the mechanized planar tomography system, TomoCAR, was already introduced, with one could measure cross-sectional images. TomoWELD uses a new photon counting and energy resolving detector with CdTe-CMOS crystal hybrids. The new detector allows the choice of energy thresholds, and enables the reduction of the influence of scattered radiation on the radiographic images and the reconstructed cross-sectional images. An optimized irradiation geometry with a new manipulator design and a fast GPU-based reconstruction algorithm can be used to accelerate the reconstruction and to improve the reconstruction results. The size and the shape of planar and voluminous irregularities can be determined. The concept and the first pictures will be presented. (Contains mainly PowerPoint slides). [German] Der neue Standard ISO 17636-2:2013 ''ZfP von Schweissnaehten - Durchstrahlungspruefung - Teil 2: Roentgen- und Gammastrahlungstechniken mit digitalen Detektoren'' definiert die Pruefpraxis fuer die digitale Radiographie von Schweissnaehten fuer die Herstellung und In-Service- Pruefung. Ausserdem wurde die DIN 25435

Structure/property relationships in multipass GMA welding of beryllium.

Energy Technology Data Exchange (ETDEWEB)

Hochanadel, P. W. (Patrick W.); Hults, W. L. (William L.); Thoma, D. J. (Dan J.); Dave, V. R. (Vivek R.); Kelly, A. M. (Anna Marie); Pappin, P. A. (Pallas A.); Cola, M. J. (Mark J.); Burgardt, P. (Paul)

2001-01-01

Beryllium is an interesting metal that has a strength to weight ratio six times that of steel. Because of its unique mechanical properties, beryllium is used in aerospace applications such as satellites. In addition, beryllium is also used in x-ray windows because it is nearly transparent to x-rays. Joining of beryllium has been studied for decades (Ref.l). Typically joining processes include braze-welding (either with gas tungsten arc or gas metal arc), soldering, brazing, and electron beam welding. Cracking which resulted from electron beam welding was recently studied to provide structure/property relationships in autogenous welds (Ref. 2). Braze-welding utilizes a welding arc to melt filler, and only a small amount of base metal is melted and incorporated into the weld pool. Very little has been done to characterize the braze-weld in terms of the structure/property relationships, especially with reference to multipass welding. Thus, this investigation was undertaken to evaluate the effects of multiple passes on microstructure, weld metal composition, and resulting material properties for beryllium welded with aluminum-silicon filler metal.

Thermal-deformation effect of welding on A 1 reactor pressure vessel weld joints properties and state of stress

International Nuclear Information System (INIS)

Becka, J.; Kupka, I.

1976-01-01

The methods are compared of electroslag welding and of arc welding with a view to their possible application in welding the Bohunice A-1 reactor pressure vessel. Considered are the thermal deformation effects of welding on the physical properties and the stress present in welded joints. For testing, plates were used having the dimensions of 1100x2300x200 mm and rings with 4820 mm outer diameter, 1800 mm height and 170 mm thickness made of steel CSN 413O30 modified with Ni, Al+Ti. The deformation effect of welding on the residual surface and triaxial stress, the specific stored energy, the initiation temperature of brittle crack and the critical size of the initiation defect corresponding to the thermal deformation effect of welding were determined. It was found that for electroslag welding, there is a low probability of crack formation in the joints, a low level of residual stress and a low level of specific stored energy in a relatively wide joint zone. For arc welding there is a considerable probability of defect formation in the vicinity of the sharp boundary of the joint, a high level of the triaxial state of stress in the tensile region, and a high level of specific stored energy concentrated in the narrow zone of weld joints. The recommended thermal process is given for welding pressure vessels made of the CSN 413030 steel modified with Ni, Al+Ti, and 150 to 200 mm in thickness. (J.P.)

Viewing Welds By Computer Tomography

Science.gov (United States)

Pascua, Antonio G.; Roy, Jagatjit

1990-01-01

Computer tomography system used to inspect welds for root penetration. Source illuminates rotating welded part with fan-shaped beam of x rays or gamma rays. Detectors in circular array on opposite side of part intercept beam and convert it into electrical signals. Computer processes signals into image of cross section of weld. Image displayed on video monitor. System offers only nondestructive way to check penetration from outside when inner surfaces inaccessible.

On use of weld zone temperatures for online monitoring of weld quality in friction stir welding of naturally aged aluminium alloys

International Nuclear Information System (INIS)

Imam, Murshid; Biswas, Kajal; Racherla, Vikranth

2013-01-01

Highlights: • FSWs for 6063-T4 AA are done at different process parameters and sheet thicknesses. • Weld nugget zone and heat affected zone temperatures are monitored for each case. • Microstructural and mechanical characterisation of welds is done in all cases. • Weld ductility is found to be particularly sensitive to weld zone temperatures. • Strong correlation is found between WNZ and HAZ temperatures and weld properties. - Abstract: 6063-T4 aluminium alloy sheets of 3 and 6 mm thicknesses were friction stir butt welded using a square tool pin at a wide range of tool rotational speeds. Properties of obtained welds were characterised using tensile tests, optical micrographs, X-ray diffraction, and transmission electron microscopy. Shape, size, and distribution of precipitates in weld zones, and strength and ductility of welds were seen to directly correlate with peak temperatures in weld nugget and heat affected zones, independent of sheet thickness. In addition, fluctuations in measured temperature profiles, for 3 mm sheets, were seen to correlate with an increase in scatter of weld nugget zone properties for 3 mm sheets. Optimal weld strength and ductility were obtained for peak weld nugget zone temperatures of around 450 °C and corresponding peak heat affected zone temperatures of around 360–380 °C. Results obtained suggest that, at least for naturally aged aluminium alloys, nature of temperature evolution and magnitudes of peak temperatures in weld nugget and heat affected zones provide information on uniformity of properties in weld zones, overaging of heat affected zones, and formation of tunnel defects from improper material mixing at low weld zone temperatures

The effect of controlled shot peening on fusion welded joints

International Nuclear Information System (INIS)

Lah, Nur Azida Che; Ali, Aidy; Ismail, Napsiah; Chai, Lim Poon; Mohamed, Abdul Aziz

2010-01-01

This work examines the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel welded joint. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity, inclusions, lack of penetration, and undercut found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed joints were compared. It was observed that the effect of the CSP and skimming processes improved the fatigue life of the fusion weld by 50% on MMA-welded, 63% on MIG-welded, and 60% on TIG-welded samples.

Effects of microplasma arc AISI 316L welds on the corrosion behaviour of pipelines in LiBr cooling systems

International Nuclear Information System (INIS)

Sánchez-Tovar, R.; Montañés, M.T.; García-Antón, J.

2013-01-01

Highlights: •SECM tests reveal differences in electrochemical activity of base and welded alloys. •The highest electrochemical activity is obtained for the welded alloy. •Microplasma arc welding process hinders passivation in lithium bromide. •Microplasma arc welding increases corrosion rate and susceptibility to pitting. •The galvanic pair between base and welded alloys in LiBr is weak. -- Abstract: The effect of microplasma arc welding (MPAW) on the electrochemical and corrosion behaviour of AISI 316L stainless steel tubes has been studied. Scanning electrochemical measurements were performed in sodium chloride to evaluate the difference in the electrochemical activity of base (non-welded) and welded samples. Oxygen reduction rates increase in AISI 316L due to the heat treatment effect induced by welding, indicating a higher electrochemical activity in the welded samples. Additionally, the use of MPA weldments in lithium bromide (LiBr) absorption machines was also analysed at typical operating temperatures and Reynolds numbers. The welding process increases corrosion rates, hinders passivation and increases the susceptibility to pitting attack in LiBr. However, zero-resistance ammeter and localization index measurements show that the galvanic pair generated between the base and welded alloys is weak, both electrodes being in their passive state. Temperature greatly affects the corrosion process

THE 70 MONTH SWIFT-BAT ALL-SKY HARD X-RAY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Baumgartner, W. H.; Tueller, J.; Markwardt, C. B.; Skinner, G. K.; Barthelmy, S.; Gehrels, N. [NASA/Goddard Space Flight Center, Astrophysics Science Division, Greenbelt, MD 20771 (United States); Mushotzky, R. F. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Evans, P. A., E-mail: whbaumga@alum.mit.edu [X-Ray and Observational Astronomy Group/Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom)

2013-08-15

We present the catalog of sources detected in 70 months of observations with the Burst Alert Telescope (BAT) hard X-ray detector on the Swift gamma-ray burst observatory. The Swift-BAT 70 month survey has detected 1171 hard X-ray sources (more than twice as many sources as the previous 22 month survey) in the 14-195 keV band down to a significance level of 4.8{sigma}, associated with 1210 counterparts. The 70 month Swift-BAT survey is the most sensitive and uniform hard X-ray all-sky survey and reaches a flux level of 1.03 Multiplication-Sign 10{sup -11} erg s{sup -1} cm{sup -2} over 50% of the sky and 1.34 Multiplication-Sign 10{sup -11} erg s{sup -1} cm{sup -2} over 90% of the sky. The majority of new sources in the 70 month survey continue to be active galactic nuclei, with over 700 in the catalog. As part of this new edition of the Swift-BAT catalog, we also make available eight-channel spectra and monthly sampled light curves for each object detected in the survey in the online journal and at the Swift-BAT 70 month Web site.

THE 70 MONTH SWIFT-BAT ALL-SKY HARD X-RAY SURVEY

International Nuclear Information System (INIS)

Baumgartner, W. H.; Tueller, J.; Markwardt, C. B.; Skinner, G. K.; Barthelmy, S.; Gehrels, N.; Mushotzky, R. F.; Evans, P. A.

2013-01-01

We present the catalog of sources detected in 70 months of observations with the Burst Alert Telescope (BAT) hard X-ray detector on the Swift gamma-ray burst observatory. The Swift-BAT 70 month survey has detected 1171 hard X-ray sources (more than twice as many sources as the previous 22 month survey) in the 14-195 keV band down to a significance level of 4.8σ, associated with 1210 counterparts. The 70 month Swift-BAT survey is the most sensitive and uniform hard X-ray all-sky survey and reaches a flux level of 1.03 × 10 –11 erg s –1 cm –2 over 50% of the sky and 1.34 × 10 –11 erg s –1 cm –2 over 90% of the sky. The majority of new sources in the 70 month survey continue to be active galactic nuclei, with over 700 in the catalog. As part of this new edition of the Swift-BAT catalog, we also make available eight-channel spectra and monthly sampled light curves for each object detected in the survey in the online journal and at the Swift-BAT 70 month Web site

Effect of weld morphology on mechanical response and failure of friction stir welds in a naturally aged aluminium alloy

International Nuclear Information System (INIS)

Imam, Murshid; Biswas, Kajal; Racherla, Vikranth

2013-01-01

Highlights: ► Friction stir welds of AA 6063-T4 are obtained using three tool pin profiles. ► Signature of weld defects in mechanical response of welds is investigated. ► Correlation between peak temperatures in HAZs and their hardness is studied. ► Reasons for strengthening of WNZ and softening of HAZs are found using TEM and XRD. ► A FEM model for the weld zone is developed and validated. -- Abstract: Friction stir butt welds in 6063-T4 aluminium alloy were obtained using square and two tapered tool pin profiles. Tensile tests at 0°, 45°, and 90° to the weld line, hardness contours in the weld cross-section, temperatures in the heat affected zones, cross-sectional macrographs, transmission electron micrographs, and X-ray diffraction studies were used to characterize the welds. In transverse weld specimen, tunnel defects appearing at higher weld speeds for tapered pin profiles, were found to result in mechanical instabilities, i.e. sharp drops in load–displacement curves, much before macroscopic necking occured. Further, in comparison to the base metal, a marked reduction in ductility was observed even in transverse specimen with defect free welds. Hardness contours in the weld cross-section suggest that loss in ductility is due to significant softening in heat affected zone on the retreating side. Transmission electron microscopy images demonstrate that while recovery and overaging are responsible for softening in the heat affected zone, grain size refinement from dynamic recrystallization is responsible for strengthening of the weld nugget zone. X-ray diffraction studies in the three weld zones: weld nugget zone, heat affected zone, and the base metal corroborate these findings. A weld zone model, for use in forming simulations on friction stir welded plates of naturally aged aluminium alloys, was proposed based on mechanical characterization tests. The model was validated using finite element analysis.

Investigation on welding and cutting methods for blanket support legs of fusion experimental reactors

International Nuclear Information System (INIS)

Tokami, Ikuhide; Nakahira, Masataka; Kurasawa, Toshimasa; Sato, Satoshi; Furuya, Kazuyuki; Hatano, Toshihisa; Takatsu, Hideyuki; Kuroda, Toshimasa.

1996-07-01

A toroidally-and poloidally-divided modular blanket has been proposed for a fusion experimental reactor, such as ITER, to enhance its maintainability as well as improve its fabricability. The blanket module, typically the size of 1 m wide, 1-2 m high and 0.4 m deep and the weight of 4 ton, will be supported by support legs which are extruded from back of the module and connected to a 70-100 mm thick strong back plate. The support leg has to withstand large electromagnetic force during plasma disruption and provide the way for in-situ module replacement by remote handling. For the connection method of the support leg to the back plate, a welding approach has been investigated here in terms of its high reliability against the large electromagnetic loads. For the welding approach, the support leg needs to be 70 mm thick, and the working space for welding/cutting heads are limited to 100 mm x 150 mm adjacent to the support leg. Based on a comparison of several welding methods, e.g. NGTIG, NGMIG and laser, NGTIG has been selected as a reference due to its well-established technology and the least R and D required. As for the cutting method, a plasma cutting has been given the highest priority to be pursued because of its compactness and high speed. Through preliminary design studies, the possibility of small welding/cutting heads that will work in the limited space has been shown, and maintenance route for in-situ module replacement with pre-and postfixture of the module has been investigated. Also preliminary R and Ds have resulted in; 1)the welding distortion is predictable according to the shape of weld groove and adjustable to meet the placement requirement of the module first wall, 2)the plasma cut surface can be rewelded without machining, 3)the welding/cutting time will meet the requirement of maintenance time. (author)

Influence of the welding temperature and the welding speed on the mechanical properties of friction stir welds in EN AW-2219-T87

Science.gov (United States)

Bachmann, A.; Krutzlinger, M.; Zaeh, M. F.

2018-06-01

Friction Stir Welding (FSW) is an innovative joining technique, which has proven to produce high quality joints in high strength aluminum alloys. Consequently, it is commonly used to manufacture lightweight aerospace structures with stringent requirements. For these structures, it is necessary to ensure a high ultimate tensile strength (UTS). Various studies have reported that the UTS is significantly influenced by the welding parameters. Samples welded with different parameter sets showed a considerably different UTS, despite being free from detectable welding defects (e.g. tunnel defect, voids, or lack of penetration). Based on the observations in the literature, a hypothesis was posed. The welding temperature along with the welding speed determine the UTS of the weld. This study aims to prove this hypothesis experimentally by using temperature-controlled FSW to join plates of EN AW-2219-T87 in butt joint configuration. The welded samples were examined using visual inspection, metallography, X-ray imaging, and uniaxial tensile tests. Finally, a statistical analysis was conducted. Hereby, the hypothesis was confirmed.

Effects of welding parameters on friction stir spot welding of high density polyethylene sheets

International Nuclear Information System (INIS)

Bilici, Mustafa Kemal; Yukler, Ahmet Irfan

2012-01-01

Graphical abstract: (a) Schematic illustration of the cross section of a friction stir spot weld and (b) Geometry of the weld bonded area, x: nugget thickness and y: the thickness of the upper sheet. Highlights: → Welding parameters affect the FSSW nugget formation and the strength of the joint. → Melting of polyethylene occurred in the vicinity of the tool pin. → The joint that fractures with a pull nugget failure mode has a higher strength. -- Abstract: Friction stir spot welding parameters affect the weld strength of thermoplastics, such as high density polyethylene (HDPE) sheets. The effects of the welding parameters on static strength of friction stir spot welds of high density polyethylene sheets were investigated. For maximizing the weld strength, the selection of welding parameters is very important. In lap-shear tests two fracture modes were observed; cross nugget failure and pull nugget failure. The tool rotational speed, tool plunge depth and dwell time were determined to be important in the joint formation and its strength. The joint which had a better strength fails with a pull nugget failure morphology. Weld cross section image analysis of the joints were done with a video spectral comparator. The plunge rate of the tool was determined to have a negligible effect on friction stir spot welding.

Experimental investigation on the weld pool formation process in plasma keyhole arc welding

Science.gov (United States)

Van Anh, Nguyen; Tashiro, Shinichi; Van Hanh, Bui; Tanaka, Manabu

2018-01-01

This paper seeks to clarify the weld pool formation process in plasma keyhole arc welding (PKAW). We adopted, for the first time, the measurement of the 3D convection inside the weld pool in PKAW by stereo synchronous imaging of tungsten tracer particles using two sets of x-ray transmission systems. The 2D convection on the weld pool surface was also measured using zirconia tracer particles. Through these measurements, the convection in a wide range of weld pools from the vicinity of the keyhole to the rear region was successfully visualized. In order to discuss the heat transport process in a weld pool, the 2D temperature distribution on the weld pool surface was also measured by two-color pyrometry. The results of the comprehensive experimental measurement indicate that the shear force due to plasma flow is found to be the dominant driving force in the weld pool formation process in PKAW. Thus, heat transport in a weld pool is considered to be governed by two large convective patterns near the keyhole: (1) eddy pairs on the surface (perpendicular to the torch axis), and (2) eddy pairs on the bulk of the weld pool (on the plane of the torch). They are formed with an equal velocity of approximately 0.35 m s-1 and are mainly driven by shear force. Furthermore, the flow velocity of the weld pool convection becomes considerably higher than that of other welding processes, such as TIG welding and GMA welding, due to larger plasma flow velocity.

Ultrasonic defect detection method for socket welding joint

International Nuclear Information System (INIS)

Tominaga, Masaaki; Matsuo, Toshiyuki; Ueno, Akihiro; Watanabe, Kunimichi; Kawamata, Kunio.

1995-01-01

The present invention provides a method of detecting defects over a wide range of a socket weld portion of various kinds of pipelines used, for example, in a nuclear power plant. Namely, an inclined probe is disposed to a jig for detecting defects by ultrasonic waves. This is rotated at least by one turn along the peripheral surface of the material to be detected such as weld tube joints. Defects of weld portion of the material can be detected automatically by using ultrasonic waves during the rotation. The inclined probe for detecting defects by ultrasonic waves comprises a transmission portion having a planar transmittance oscillator disposed to a wedge on the transmission side and a receiving portion comprising a planar receiving oscillator disposed to a wedge on the receiving side. With such a constitution, ultrasonic waves are emitted from the transmission portion to the defect detection portion in the welded portion. If a defect is present, defective echo is reflected to the receiving portion disposed ahead of the probe. Since the defective echo changes depending on the height of the detective portion, the estimation of the height of the defect can be facilitated. (I.S.)

Research into the transmission of natural gas by gas pipeline

Energy Technology Data Exchange (ETDEWEB)

Gadonneix, P.

1998-12-31

This paper is the press release of the talk given at the `Gaz de France scientific meeting with the press` by P. Gadonneix, chairman of Gaz de France company, on October 7, 1998. The aim of this talk concerns the new French and European supply link for bringing natural gas from the Norwegian North Sea fields. This new supply link is the first direct link between Norway and France and the NorFra gas pipeline which brings natural gas from the North Sea to France is the longest offshore pipeline in the world. The `Artere des Hauts de France` pipeline (the largest diameter gas pipeline ever laid in France) is devoted to the transfer of natural gas from Dunkerque to the Gournay-sur-Aronde underground storage site. This paper describes successively: the French European gas supply hub, the NorFra project, the Artere des Hauts de France pipeline, the network performance research, the safety and quality guaranties, the reduction of overland natural gas transmission costs (improvement of pipe-laying techniques and optimization of line route and welding operations), the specific techniques used for road and river crossing (micro-tunnel digging, river-crossing ditches) and for anchoring (buoyancy compensation). Finally, the environmental impact of the laying operations is briefly described. (J.S.)

Stands for testing the strength of welded pipe materials under the action of a corrosive medium

Directory of Open Access Journals (Sweden)

M.A. Kolodyi

2017-12-01

Full Text Available In order to study the features of the destruction of materials of pipelines for the transportation of oil, gas, products of processing of oil, water and other substances in the laboratory of the department of development of minerals named by prof. Bakka N.T. the complex of installations is invented, for which Ukrainian patents were obtained as utility models No. 30794, No. 52493, for the study of the working capacity of the elements of the listed pipeline systems in conditions that are as close as possible to the operational under the influence of the corrosive medium. Rotary vacuum devices were used as the basic elements of the proposed installations for testing the materials of the welded tubes for durability at single tensile and under flat stress conditions. The article presents the design of research stands for testing the durability of pipe materials and welds of pipelines using samples of materials and natural pipes (shortened under the influence of static, low cyclic and dynamic loads, and analyzes the influence of aggressive media.

Study of texture and microstructure evaluation of steel API 5L X70 under various thermomechanical cycles

Energy Technology Data Exchange (ETDEWEB)

Masoumi, Mohammad, E-mail: Mohammad@alu.ufc.br; Herculano, Luis Flavio Gaspar; Ferreira Gomes de Abreu, Hamilton

2015-07-15

This work studies the influence of different thermomechanical paths on the microstructure and crystallographic texture across the thickness of API 5L X70 pipeline steel manufactured via hot rolling using X-ray diffraction (XRD), scanning electron microscope (SEM), and electron backscattered diffraction (EBSD). The starting materials were controlled hot-rolled at 1000 °C to 44% and 67% reductions and subsequently heat treated with such processes as annealing, water quenching and quench tempering at three different temperatures to evaluate the microstructure and crystallographic texture changes across the thickness. The banded ferrite-pearlite microstructure of the initial material was changed to acicular ferrite, quasi-polygonal ferrite, granular bainite, martensite and retained austenite via different heat treatments. Moreover, different thermomechanical paths induced crystallographic texture variations across the thickness, e.g., {112}//ND, {111}//ND (γ fibre), and {011}//ND fibres dominated on the surface plane in contact with the rolls, whereas {001}//ND and particularly the (001)[1 1 0] texture component developed in the centre plane on which shear deformation has a zero value in this region. In this study, a simple interpretation of texture evolution was analyzed by comparison with the orientation changes that occurred during different rolling schedules and post-treatment processes.

Study on the abnormal image appeared in radiographs of welds, 3

International Nuclear Information System (INIS)

Hayashi, Morihiro; Sugimura, Seiichi; Umemura, Kunio; Imamura, Senji; Kanno, Munekazu.

1984-01-01

On the abnormal images arising at times in the X-ray radiographs of austenitic stainless steel welded parts, the cause of occurrence was clarified before. In this study, the authors made the welded parts of austenitic stainless steel SUS 304 and SUS 316 with abnormal images of different clearness by making heat input into respective layers of welds large or small, and compared the static and dynamic strength. Moreover, the relation of the form of abnormal images in radiographs to metal structures was studied. The welding method employed was TIG welding and submerged arc welding. The images of X-ray radiographs and the metal structures of the welded parts tested are shown. The mechanical strength test was carried out by tension, bending and impact. Also fatigue test was performed. In the welded parts of SUS 304 and SUS 316, even if abnormal images appeared in radiographs, when sound welding was made, they possessed sufficient strength statically and dynamically. In the macroscopic and microscopic cross-sectional structures of the welded parts with remarkable abnormal images, defect was not observed at all. The cause of abnormal image appearance is the diffraction of X-ray. (Kako, I.)

Electron beam welding of iridium heat source capsules

International Nuclear Information System (INIS)

Mustaleski, T.M.; Yearwood, J.C.; Burgan, C.E.; Green, L.A.

1991-01-01

The development of the welding procedures for the production of DOP-26 iridium alloy cups for heat source encapsulation is described. All the final assembly welds were made using the electron beam welding process. The welding of the 0.13-mm weld shield required the use of computer controlled X-Y table and a run-off tab. Welding of the frit vent to the cup required that a laser weld be made to hold the frit assembly edges together for the final electron beam weld. Great care is required in tooling design and beam placement to achieve acceptable results. Unsuccessful attempts to use laser beam welding for heat shield butt weld are discussed

Emissions of polluting substances in the atmosphere at construction of the pipeline Bolshoy Chagan - Atyrau

International Nuclear Information System (INIS)

Gilazhov, E.G.

2005-01-01

Full text : The main pipelines of Kazakhstan represent the most complicated mechanized and the automated hydraulic system which has been very branched out and long. It is equipped by powerful pump stations, lines and constructions of technological communication, telemechanics and automatics, fire-prevention devices, on occasion - furnaces of heating. Construction Oil and gas pipeline Bolschoy Chagan - Atyrau is intended for transportation of a mix of oil, acting on NPS Bolschoy Chagan with Karachaganak Oil and gas deposits (KNGKM), up to Atyrau for pumping in pipeline system of the Caspian pipeline consortium. The maximal volume of a transported product from Bolschoy Chagan up to pipeline KTK will make 10 million tons a year at full projected volume from KNGKM up to Atyrau - 11 million tons/years. The line Oil and gas pipeline Bolschoy Chagan - Atyrau is covered by a network of highways - soil, rural, with a covering and with the improved covering. The largest settlements located in a strip of passage of a line the following: Bolschoy Chagan, Kushum, Budarino, Chapaev, Mergenevo, Lbishchenskoe, Tajpak, Eltaj, Kulagino, Orlik, Green, Mahambet, Sarajshyk. The line Oil and gas pipeline represents a broken line in length of 455,25 km, stretched with the north on the south. The Earth, allocated under construction Oil and gas pipeline now are used for an agricultural production, mainly pasturable cattle breeding, and also in a small degree for cultivation grain, vegetable and agro cultures. According to influence of the equipment used at construction and operation Oil and gas pipeline on atmospheric air, inventory of sources of emissions is lead to an atmosphere in view of duration of work during which sources of emissions have been revealed all, total and as much as possible single emissions from stationary sources are calculated. It has been revealed, that here take place, both stationary sources of emissions, and mobile to which all motor transport concerns, and also

Structure of pipeline or duct for thermonuclear reactor

International Nuclear Information System (INIS)

Yamazaki, Seiichiro; Kobayashi, Takeshi; Fujioka, Junzo; Nishio, Satoshi; Okawa, Yoshinao; Sato, Keisuke.

1992-01-01

An electrically insulating material comprising a gradient function material is bonded metallurgically to a pipeline or a duct to be disposed to a magnetic field-confining type thermonuclear reactor. The gradient material has an ingredient approximate to ceramics on the side of an electrically insulative ceramic portion and an ingredient approximate to a metal on the other side. The intermediate portion between them, has a continuous gradient ingredient. Further, in the gradient portion of the electrically insulative portion, a heat expansion coefficient is also varied continuously or stepwise in addition to the electrical insulative property. Accordingly, even when a temperature distribution is caused during operation and welding upon production, thermal stresses applied to the pipelines is moderated. Further, since the electrically insulative ceramics are interposed with no support by an electric conductor, sufficient electrical insulation can be ensured. (T.M.)

Experimental study on variations in Charpy impact energies of low carbon steel, depending on welding and specimen cutting method

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhaorui; Kang, Hansaem; Lee, Young Seog [Chung-Ang University, Seoul (Korea, Republic of)

2016-05-15

This paper presents an experimental study that examines variations of Charpy impact energy of a welded steel plate, depending upon the welding method and the method for obtaining the Charpy specimens. Flux cored arc welding (FCAW) and Gas tungsten arc welding (GTAW) were employed to weld an SA516 Gr. 70 steel plate. The methods of wire cutting and water-jet cutting were adopted to take samples from the welded plate. The samples were machined according to the recommendations of ASTM SEC. II SA370, in order to fit the specimen dimension that the Charpy impact test requires. An X-ray diffraction (XRD) method was used to measure the as-weld residual stress and its redistribution after the samples were cut. The Charpy impact energy of specimens was considerably dependent on the cutting methods and locations in the welded plate where the specimens were taken. The specimens that were cut by water jet followed by FCAW have the greatest resistance-to-fracture (Charpy impact energy). Regardless of which welding method was used, redistributed transverse residual stress becomes compressive when the specimens are prepared using water-jet cutting. Meanwhile, redistributed transverse residual stress becomes tensile when the specimens are prepared using wire cutting.

Friction weld ductility and toughness as influenced by inclusion morphology

International Nuclear Information System (INIS)

Eberhard, B.J.; Schaaf, B.W. Jr.; Wilson, A.D.

1983-01-01

Friction welding consistently provides high strength, freedom from fusion defects, and high productivity. However, friction welds in carbon steel exhibit impact toughness and bend ductility that are significantly lower than that of the base metal. The inclusion content and morphology were suspected to be major contributors to the reduction in weld ductility. For this reason, four electric furnace steels - three types of ASTM A516 Grade 70, and an ASTM A737 Grade B steel - were investigated. Friction welds were made by both the inertia and direct drive process variations and the welds evaluated. It was shown that friction welds of inclusion-controlled steels exhibited much improved toughness and bend ductility were demonstrated. Upper shelf impact energy was equivalent to or greater than that of the base metal in the short transverse direction. The transition temperature range for all four materials was shifted to higher temperatures for both types of friction welds. Under the conditions of this test, the direct drive friction welds showed a greater shift than the inertia friction welds. The ductility and toughness of welds in A737 Grade B steel were superior to welds in A516 Grade 70 steels, reflecting the superior properties of the base metal. Welds of the A737 material had usable Charpy V-notch impact toughness of 20 to 30 ft-lb (27 to 41 J) at temperatures as low as -40 0 F (-40 0 C). All the welds had an acicular structure. The differences in properties between the inertia and direct drive friction welds appear associated with microstructural variations. These variations resulted from the different heat inputs and cooling rates of the two process variations were demonstrated. The beneficial effects of inclusion control on toughness and ductility. In addition, it also indicates that additional improvements may be attainable through control of the as-welded microstructure by process manipulation

Robotic system for orbital welding of pipes; Sistema robotizado para soldagem orbital de dutos

Energy Technology Data Exchange (ETDEWEB)

Bracarense, Alexandre Queiroz; Lima, II, Eduardo Jose; Torres, Guilherme Fortunato; Ramalho, Frederico [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Felizardo, Ivanilza; Zanon, Gislaine Pires [ROTECH Tecnologia Robotica Ltda., Belo Horizonte, MG (Brazil)

2004-07-01

This work presents the robotic system projected for orbital welding of pipelines of oil and gas. The system consists of a controller (microcomputer), that allows the execution of all the referring tasks to the welding in an autonomous way, and two manipulates, to what are coupled the welding torches that are connected to a welding power source with double wire feeders. With this system, GMA W process is used to execute the root pass, while FCA W process, besides the GMA W, is used for the filling and finishing passes. The system has four degrees of freedom, allowing the control of stick out, travel speed, torch angle and positioning. Besides these, the arc voltage and and welding current are also controlled during the process. Knowing that for each welding position (plane, vertical up and down and over head) a great group of parameters must be used, several tests were accomplished. With these values a controlled variation could be accomplished in an uninterrupted way when welding position changes, getting the increase of the productivity and also the quality of the weld performed by a robotic system. (author)

Construction of pipelines on marshlands during summer months with the aid of gang assembly platforms

Energy Technology Data Exchange (ETDEWEB)

Kovalev, E P; Girshovich, I I

1979-05-01

Because the massive size of conventional pipeline-construction equipment limits its use in swampy areas to winter months, the USSR's SKB Gazstroimashina developed a new system to allow year-round construction activity. The equipment consists of five mobile platforms arranged in series along the pipeline to spread out the load for a lower specific ground pressure than exerted by conventional equipment. Platforms perform the successive functions of emplacement of the pipe lengths, end preparation, welding, cleanup, and insulation. So far, two sets of gang-assembly platforms have been built and are being field-tested.

The Measurement of Hardness and Elastic Modulus of non-Metallic Inclusions in Steely Welding Joints

Directory of Open Access Journals (Sweden)

Ignatova Anna

2015-08-01

Full Text Available Trunk pipelines work under a cyclic dynamical mechanical load because when oil or gas is pumped, the pressure constantly changes - pulsates. Therefore, the fatigue phenomenon is a common reason of accidents. The fatigue phenomenon more often happens in the zone of non-metallic inclusions concentration. To know how the characteristics of nonmetallic inclusions influence the probability of an accident the most modern research methods should be used. It is determined with the help of the modern research methods that the accident rate of welded joints of pipelines is mostly influenced by their morphological type, composition and size of nonmetallic inclusions, this effect is more important than the common level of pollution by non-metallic inclusions. The article presents the results of the investigations of welded joints, obtained after the use of different common welding materials. We used the methods, described in the state standards: scanning electronic microscopy, spectral microprobe analysis and nano-indentation. We found out that non-metallic inclusions act like stress concentrators because they shrink, forming a blank space between metal and nonmetallic inclusions; it strengthens the differential properties on this boundary. Nonmetallic inclusion is not fixed, it can move. The data that we have received mean that during welded joints’ contamination (with non-metallic inclusions monitoring process, more attention should be paid to the content of definite inclusions, but not to total contamination.

Hydrogen sulfide corrosion of weld regions in API X52 steel; Corrosion por acido sulfhidrico de las regiones de soldadura en acero API X52

Energy Technology Data Exchange (ETDEWEB)

Arenas-Martinez, L.F [Universidad Autonoma de Coahuila, Coahuila (Mexico)]. E-mail: fernando.arenas@uadec.edu.mx; Garcia-Cerecero, G. [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V., Saltillo, Coahuila (Mexico)

2012-10-15

The corrosion behavior of gas metal arc welding (GMAW) regions has been studied using potentiodynamic polarization and polarization resistance (LPR) techniques. Experiments were conducted in hydrogen sulfide (H{sub 2}S)-containing brine and in H{sub 2}S-free brine. Welds were made on API 5L X52 steel. Due to differences in their microstructure, chemical composition and residual stress level, weld regions exhibited different responses under H{sub 2}S corrosion. Base metal exhibited the highest corrosion rate (CR) and the most cathodic corrosion potential. [Spanish] Se estudio el comportamiento ante la corrosion de las regiones de soldadura de un cordon realizado por arco metalico con gas (GMAW) sobre un acero grado API X52 mediante las tecnicas de polarizacion potencio dinamica y resistencia a la polarizacion (LPR). Los experimentos se realizaron utilizando salmuera con 300 ppm de acido sulfhidrico (H{sub 2}S) y salmuera libre de H{sub 2}S como electrolitos. Debido a las diferencias en su microestructura, composicion quimica y el nivel de esfuerzos residuales, las regiones de soldadura mostraron diferentes respuestas a la corrosion por H{sub 2}S. El metal base exhibio la velocidad de corrosion (VC) mas alta y el potencial de corrosion mas catodico.

Development of a robotic manipulator for orbital welding; Desenvolvimento de um manipulador robotico para a sondagem orbital

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Renon Steinbach; Dutra, Jair Carlos [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Lab. de Soldagem; Bonacorso, Nelso Gauze [Centro Federal de Educacao Tecnologica de Santa Catarina (CEFET/SC), Florianopolis, SC (Brazil). Lab. da Automacao Hidraulica e Pneumatica (LAHP)

2008-07-01

On the national oil scenario, the pipelines have a high cost, specially on the long time spent on its constructions. Thus, this transaction optimizations become highly attractive. A form of improvement this task is to automate the process of welding. In this context it is interesting the use of a robot manipulator for the orbital welding. In the international market, there are dedicates solutions that meet the restrictions associated mainly with the ease of handling and dimensions. However,since these manipulators use foreign technology this makes the acquisition and maintenance costs high. The project aims to create subsides for greater efficiency in the task of union of pipelines through the development of a robotic manipulator. However it is clear that only the design of such a handler does not guarantee the quality of the root pass. Therefore, it is also being studied the use of the process MIG (Metal Inert Gas), through parametrization of CCC (Short-circuit controlled) in order to have a robust process of welding. The CCC monitors the process of welding and acts when there is detection od short circuit. It is obtained then higher pass from scratch controllability and drastically reduces the amount of spay. (author)

Friction stir welding of 6061 aluminium alloy

International Nuclear Information System (INIS)

Abdel Rahman, M.A.M.S.

2009-01-01

6061 AA (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio and good corrosion resistance such as marine frames, pipelines, storage tanks, and aircraft components [1]. It is also used for the manufacturing of fuel elements in the nuclear research reactors. Compared to many of the fusion welding processes that are routinely used for joining structural alloys, friction stir welding (FSW) is a solid state joining process in which the material that is being welded is not melted and recast [2]. The welding parameters such as tool rotational speed, welding traverse speed, and tool profile play a major role in deciding the weld quality. Several FSW tools (differ from each other in pin angle, shoulder diameter, and shoulder concavity) have been used to fabricate a number of joints in order to obtain a tool with which a sound weld can be produced. It was found that the FSW tool with tapered cone pin, concave shoulder, and shoulder diameter equal to four times the welded plate thickness is suitable to produce a sound weld. The effect of the traverse speed on the global and local tensile properties of friction stir welded joints has been investigated in the 6061-T6 AA. The global tensile properties of the FSW joints were improved with increasing the traverse speed at constant rotation rate. It is found that the global tensile strength of the FSW joint is limited by the local tensile strength of the nearest region to the weld center at which the cross section is composed mainly of the HAZ. The effect of the initial butt surface on the formation of the zigzag line on the tensile properties of the welds was examined by using three types of welding samples differ in the preparation of the initial butt surface. The first type of samples welded without removing the oxide layer from the initial butt surface (uncleaned butt surfaces joint). In the second type of samples the oxide layer was removed from

Field sludge characterization obtained from inner of pipelines

Energy Technology Data Exchange (ETDEWEB)

Nava, N.; Sosa, E.; Alamilla, J.L. [Instituto Mexicano del Petroleo, Programa de Integridad de Ductos, Eje Central Lazaro Cardenas Norte 152, San Bartolo Atepehuacan, C.P. 07730 (Mexico); Knigth, C. [PEMEX Refinacion, Avenida Marina Nacional 329, Edificio B-2, Piso 11, C.P. 11311 (Mexico); Contreras, A. [Instituto Mexicano del Petroleo, Programa de Integridad de Ductos, Eje Central Lazaro Cardenas Norte 152, San Bartolo Atepehuacan, C.P. 07730 (Mexico)], E-mail: acontrer@imp.mx

2009-11-15

Physicochemical characterization of sludge obtained from refined hydrocarbons transmission pipeline was carried out through Moessbauer spectroscopy and X-ray diffraction. The Moessbauer and X-ray patterns indicate the presence of corrosion products composed of different iron oxide and sulfide phases. Hematite ({alpha}-Fe{sub 2}O{sub 3}), magnetite (Fe{sub 3}O{sub 4}), maghemite ({gamma}-Fe{sub 2}O{sub 3}), magnetic and superparamagnetic goethite ({alpha}-FeOOH), pyrrhotite (Fe{sub 1-x}S), akaganeite ({beta}-FeOOH), and lepidocrocite ({gamma}-FeOOH) were identified as corrosion products in samples obtained from pipeline transporting Magna and Premium gasoline. For diesel transmission pipeline, hematite, magnetite, and magnetic goethite were identified. Corrosion products follow a simple reaction mechanism of steel dissolution in aerated aqueous media at a near-neutral pH. Chemical composition of the corrosion products depends on H{sub 2}O and sulfur inherent in fluids (traces). These results can be useful for decision-making with regard to pipeline corrosion control.

Mechanism of selective corrosion in electrical resistance seam welded carbon steel pipe

Energy Technology Data Exchange (ETDEWEB)

Lopez Fajardo, Pedro; Godinez Salcedo, Jesus; Gonzalez Velasquez, Jorge L. [Instituto Politecnico Nacional, Mexico D.F., (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas. Dept. de Ingenieria Metalurgica

2009-07-01

In this investigation the studies of the mechanism of selective corrosion in electrical resistance welded (ERW) carbon steel pipe was started. Metallographic characterizations and evaluations for inclusions were performed. The susceptibility of ERW pipe to selective corrosion in sea water (NACE 1D182, with O{sub 2} or CO{sub 2} + H{sub 2}S) was studied by the stepped potential Potentiostatic electrochemical test method in samples of 1 cm{sup 3} (ASTM G5) internal surface of the pipe (metal base-weld). The tests were looking for means for predicting the susceptibility of ERW pipe to selective corrosion, prior to placing the pipeline in service. Manganese sulfide inclusions are observed deformed by the welding process and they are close to the weld centerline. A slight decarburization at the weld line is observed, and a distinct out bent fiber pattern remains despite the post-weld seam annealing. The microstructure of the weld region consists of primarily polygonal ferrite grains mixed with small islands of pearlite. It is possible to observe the differences of sizes of grain of the present phases in the different zones. Finally, scanning electron microscopic observation revealed that the corrosion initiates with the dissolution of MnS inclusions and with small crack between the base metal and ZAC. (author)

Plastic fracture toughness of austenitic welding connection for Ver-1000 nuclear reactor piping of 300-350 mm diameter

International Nuclear Information System (INIS)

Vasil'chenko, G.S.; Dragunov, Yu.G.; Kabelevskij, M.G.; Kazantsev, A.G.; Kunavin, S.A.; Merinov, G.N.; Sokov, L.M.

2000-01-01

The outside welding technology for circular welds in a pearlitic tube using austenitic welding wire materials is developed and applied in manufacturing pipelines of CPP and ECC. Mechanical properties and fracture toughness of austenitic welded joints in pearlitic tubes are determined to substantiate by calculation the practicality of the leakage prior to failure concept. The work is accomplished on experimental tube manufactured by hand arc welding. When manufactured the tube is cut into 5 rings. From the rings the tensile specimens are cut for testing at 20 and 350 deg C as well as Charpy V-notch impact specimens and compact specimens ST-1T. It is shown that the materials of the experimental tube meet the standard requirements. Only axial specimens cut across the weld are not in conformity with the requirements for specific elongation [ru

Nuclear fuel rod end plug weld inspection

International Nuclear Information System (INIS)

Parker, M. A.; Patrick, S. S.; Rice, G. F.

1985-01-01

Apparatus and method for testing TIG (tungsten inert gas) welds of end plugs on a sealed nuclear reactor fuel rod. An X-ray fluorescent spectrograph testing unit detects tungsten inclusion weld defects in the top end plug's seal weld. Separate ultrasonic weld inspection system testing units test the top end plug's seal and girth welds and test the bottom end plug's girth weld for penetration, porosity and wall thinning defects. The nuclear fuel rod is automatically moved into and out from each testing unit and is automatically transported between the testing units by rod handling devices. A controller supervises the operation of the testing units and the rod handling devices

Evaluation of laser welding techniques for hydrogen transmission. Final report, September 1977-November 1979

Energy Technology Data Exchange (ETDEWEB)

Mucci, J

1980-05-01

This program was established to determine the feasibility of laser beam welding as a fabrication method for hydrogen transmission and is a precursor in the effort to systematically provide the technological base necessary for large-scale, economic pipeline transmission of fuel for a hydrogen energy system. The study contributes to the technology base by establishing the effect of conventional weld processes and laser beam welding on the mechanical properties of two classes of steels in an air and high pressure gaseous hydrogen environment. Screening evaluation of the tensile, low-cycle fatigue and fracture toughness properties and metallurgical analyses provide the basis for concluding that laser beam welding of AISI 304L stainless steel and ASTM A106B carbon steel can produce weldments of comparable quality to those produced by gas-tungsten arc and electron beam welding and is at least equally compatible with 13.8 MPa (2000 psig) gaseous hydrogen environment.

Repair welding and online radiography

International Nuclear Information System (INIS)

Nuding, W.; Grimm, R.; Link, R.; Schroeder, P.; Schroeder, G.

1990-01-01

The status of a joint project is reported, which is to develop a computerized testing and welding system for repair work in turbine blades. An X-ray radiographic testing device consisting of microfocus tube, manipulator and image processing system, is modified for this purpose so as to offer a greater number of image points scanned for image processing, and to thus achieve a better resolution for reliable detection of even very small defects. The consistency of the X-ray tube performance, which is a pre-requisite for automation, is to be achieved by a wa tercooled, high-duty tube head. The recording of defect coordinates in the repair zone is done for input into a welding robot to be developed by other partners in the project, so as to allow automated welding work. (orig.) [de

Susceptibility to hydrogen-induced cracking in H2S corrosion environment of API 5L-X80 weld metal

International Nuclear Information System (INIS)

Hilton, J.; Fals, H. C.; Trevisan, R. E.

2009-01-01

The susceptibility to hydrogen-induced cracking in H 2 S environment of welded API X80 steel was studied. The flux cored arc welding (FCAW) process was employed with E71-T1 and E71-T8K6 wires. The welding parameters were kept constant, but the samples were welded using different preheat temperatures (room temperature and 100 degree centigrade). The gapped bead-on-plate (G-BOP) test was used. The specimens of modified G-BOP tests were exposed to an environment saturated in H 2 S, as recommended by the NACE TM0284 standard. The weld beads were characterized by optical microscopy and the level of residual hydrogen in the samples was measured. The fracture surface areas of hydrogen-induced cracking were calculated and the fracture mode was discussed. It was found that the preheating temperature of 100 degree centigrade was enough to avoid cracking, even in the presence of H 2 S. It was also found that the E71- T8K6 wire was more susceptible to cracking, and the typical mixed-mode fracture was predominant in all samples. (Author) 15 refs

Measuring weld heat to evaluate weld integrity

Energy Technology Data Exchange (ETDEWEB)

Schauder, V., E-mail: schauder@hks-prozesstechnik.de [HKS-Prozesstechnik GmbH, Halle (Germany)

2015-11-15

Eddy current and ultrasonic testing are suitable for tube and pipe mills and have been used for weld seam flaw detection for decades, but a new process, thermography, is an alternative. By measuring the heat signature of the weld seam as it cools, it provides information about weld integrity at and below the surface. The thermal processes used to join metals, such as plasma, induction, laser, and gas tungsten arc welding (GTAW), have improved since they were developed, and they get better with each passing year. However, no industrial process is perfect, so companies that conduct research in flaw detection likewise continue to develop and improve the technologies used to verify weld integrity: ultrasonic testing (UT), eddy current testing (ET), hydrostatic, X-ray, magnetic particle, and liquid penetrant are among the most common. Two of these are used for verifying the integrity of the continuous welds such as those used on pipe and tube mills: UT and ET. Each uses a transmitter to send waves of ultrasonic energy or electrical current through the material and a receiver (probe) to detect disturbances in the flow. The two processes often are combined to capitalize on the strengths of each. While ET is good at detecting flaws at or near the surface, UT penetrates the material, detecting subsurface flaws. One drawback is that sound waves and electrical current waves have a specific direction of travel, or an alignment. A linear defect that runs parallel to the direction of travel of the ultrasonic sound wave or a flaw that is parallel to the coil winding direction of the ET probe can go undetected. A second drawback is that they don't detect cold welds. An alternative process, thermography, works in a different fashion: It monitors the heat of the material as the weld cools. Although it measures the heat at the surface, the heat signature provides clues about cooling activity deep in the material, resulting in a thorough assessment of the weld's integrity It

Influence of Welding Time on Tensile-Shear Strength of Linear Friction Welded Birch (Betula pendula L. Wood

Directory of Open Access Journals (Sweden)

Jussi Ruponen

2015-04-01

Full Text Available The purpose of this work was to determine the optimal welding time for linear friction welding of birch (Betula pendula L. wood while keeping the other parameters constant and at similar levels compared to other species in a similar density range. Specimens with dimensions of 20 × 5 × 150 mm3 were welded together, and the influence of welding time (2.5, 3.0, 3.5, and 4.0 s on the mechanical properties of the specimens was determined. The studies included a tensile-shear strength test as well as visual estimation of wood failure percentage (WFP. Additionally, X-ray microtomographic imaging was used to investigate and characterise the bond line properties as a non-destructive testing method. The highest mean tensile-shear strength, 7.9 MPa, was reached with a welding time of 3.5 s. Generally, all four result groups showed high, yet decreasing proportional standard deviations as the welding time increased. X-ray microtomographic images and analysis express the heterogeneity of the weld line clearly as well. According to the averaged group-wise results, WFP and tensile-shear strength correlated positively with an R2 of 0.93. An extrapolation of WFP to 65% totals a tensile-shear strength of 10.6 MPa, corresponding to four common adhesive bonds determined for beech.

Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

Energy Technology Data Exchange (ETDEWEB)

Hernandez-Espejel, A. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, CICATA-Unidad Altamira-Tamaulipas, km 14.5, Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira, Tamps (Mexico); Cabrera-Sierra, R. [Instituto Politecnico Nacional, Departamento de Ingenieria Quimica Industrial, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Rodriguez-Meneses, C. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Arce-Estrada, E.M., E-mail: earce@ipn.m [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico)

2010-07-15

Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

International Nuclear Information System (INIS)

Hernandez-Espejel, A.; Dominguez-Crespo, M.A.; Cabrera-Sierra, R.; Rodriguez-Meneses, C.; Arce-Estrada, E.M.

2010-01-01

Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

Socket weld integrity in nuclear piping under fatigue loading condition

International Nuclear Information System (INIS)

Choi, Young Hwan; Choi, Sun Yeong

2007-01-01

The purpose of this paper is to evaluate the integrity of socket weld in nuclear piping under the fatigue loading. The integrity of socket weld is regarded as a safety concern in nuclear power plants because many failures have been world-widely reported in the socket weld. Recently, socket weld failures in the chemical and volume control system (CVCS) and the primary sampling system (PSS) were reported in Korean nuclear power plants. The root causes of the socket weld failures were known as the fatigue due to the pressure and/or temperature loading transients and the vibration during the plant operation. The ASME boiler and pressure vessel (B and PV) Code Sec. III requires 1/16 in. gap between the pipe and fitting in the socket weld with the weld leg size of 1.09 x t 1 , where t 1 is the pipe wall thickness. Many failure cases, however, showed that the gap requirement was not satisfied. In addition, industry has demanded the reduction of weld leg size from 1.09 x t 1 to 0.75 x t 1 . In this paper, the socket weld integrity under the fatigue loading was evaluated using three-dimensional finite element analysis considering the requirements in the ASME Code. Three types of loading conditions such as the deflection due to vibration, the pressure transient ranging from P = 0 to 15.51 MPa, and the thermal transient ranging from T = 25 to 288 deg. C were considered. The results are as follows; (1) the socket weld is susceptible to the vibration where the vibration levels exceed the requirement in the ASME operation and maintenance (OM) code. (2) The effect of pressure or temperature transient load on socket weld in CVCS and PSS is not significant owing to the low frequency of transient during plant operation. (3) 'No gap' is very risky to the socket weld integrity for the systems having the vibration condition to exceed the requirement specified in the ASME OM Code and/or the transient loading condition from P = 0 and T = 25 deg. C to P = 15.51 MPa and T = 288 deg. C. (4

Hot coiled steel strip with elevated niobium content for pipelines and its weldability

International Nuclear Information System (INIS)

Brozda, J.; Zeman, M.

2010-01-01

Examinations and tests have been performed on thermomechanically rolled and hot coiled 14 mm thick steel strips with a low carbon and elevated niobium content, assigned for the production of pipelines. There were examined basic mechanical properties of the steels, brittle fracture resistance of the parent material and simulated HAZ's, susceptibility to cold cracking as well as properties of MMA and GMA welded joints. It was found that the tested steels are characterized by a good weldability, are not prone to cold cracking, have a low brittle fracture transition temperature and the HAZ of welded joints shows a sufficient high brittle fracture resistance. (authors)

Application of Response Surface Methodology for Modeling of Postweld Heat Treatment Process in a Pressure Vessel Steel ASTM A516 Grade 70.

Science.gov (United States)

Peasura, Prachya

2015-01-01

This research studied the application of the response surface methodology (RSM) and central composite design (CCD) experiment in mathematical model and optimizes postweld heat treatment (PWHT). The material of study is a pressure vessel steel ASTM A516 grade 70 that is used for gas metal arc welding. PWHT parameters examined in this study included PWHT temperatures and time. The resulting materials were examined using CCD experiment and the RSM to determine the resulting material tensile strength test, observed with optical microscopy and scanning electron microscopy. The experimental results show that using a full quadratic model with the proposed mathematical model is YTS = -285.521 + 15.706X1 + 2.514X2 - 0.004X1(2) - 0.001X2(2) - 0.029X1X2. Tensile strength parameters of PWHT were optimized PWHT time of 5.00 hr and PWHT temperature of 645.75°C. The results show that the PWHT time is the dominant mechanism used to modify the tensile strength compared to the PWHT temperatures. This phenomenon could be explained by the fact that pearlite can contribute to higher tensile strength. Pearlite has an intensity, which results in increased material tensile strength. The research described here can be used as material data on PWHT parameters for an ASTM A516 grade 70 weld.

The investigation of typical welding defects for 5456 aluminum alloy friction stir welds

International Nuclear Information System (INIS)

Chen Huabin; Yan Keng; Lin Tao; Chen Shanben; Jiang Chengyu; Zhao Yong

2006-01-01

The external factors on the friction stir welding defects are so abundant that the experiments of friction stir welding were conducted for 5456 aluminum alloy. With the changes of the tool tilt angle and material condition, defects can be generated. These defects can be conventional ones (lack of penetration or voids), or lazy S, which are unique to friction stir welding. However, the origin of the defects remains an area of uncertainty. In this study, an attempt has been made to investigate the formation of these defects. The typical welding defects of friction stir welding joint for 5456 aluminum alloy were analyzed and discussed, respectively, by using optical microscopy (OM), energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscope (SEM). The microscopic examination of the nugget zone and fracture location of the weld confirms that the tilt angle can change the plastic material flow patterns in the stir zone and accordingly control the weld properties. In addition, the oxide layer from the initial butt surface during FSW is dispersed at the grain boundary. These A1 2 O 3 particles are actually the major cause of failure of the joint

Twin-spot laser welding of advanced high-strength multiphase microstructure steel

Science.gov (United States)

Grajcar, Adam; Morawiec, Mateusz; Różański, Maciej; Stano, Sebastian

2017-07-01

The study addresses the results concerning the laser welding of TRIP (TRansformation Induced Plasticity) steel using a beam focused at two spots (also referred to as twin-spot laser welding). The analysis involved the effect of variable welding thermal cycles on the properties and microstructure of welded joints. The tests were performed using a linear energy of 0.048 and 0.060 kJ/mm and the laser beam power distribution of 50%:50%, 60%:40% and 70%:30%. The tests also involved welding performed using a linear energy of 0.150 kJ/mm and the laser beam power distribution of 70%:30%. In addition, the research included observations of the microstructure of the fusion zone, heat affected zone and the transition zone using light microscopy and scanning electron microscopy. The fusion zone was composed of blocky-lath martensite whereas the HAZ (heat-affected zone) was characterised by the lath microstructure containing martensite, bainite and retained austenite. The distribution of twin-spot laser beam power significantly affected the microstructure and hardness profiles of welded joints. The highest hardness (480-505 HV), regardless of welding variants used, was observed in the HAZ.

Environmental management systems methodology for pipeline systems implementation; Metodologia para implantacao de sistemas de gestao ambiental na implementacao de empreendimentos dutoviarios

Energy Technology Data Exchange (ETDEWEB)

Paz, Claudio Marques [JPTE Engenharia Ltda., Barueri, SP (Brazil); Pinaud, Rodrigo Zambrotti [AJR Engenharia - Seguranca, Meio Ambiente e Saude Ltda. (Brazil)

2004-07-01

The implementation of oil and gas pipeline systems are commonly made in a own or shared with power transmission, rail and crossroads right-of-way. Pipelines are a 'linear' structure, such as power transmission lines, which are established on landscapes with several conformations (accent slopes, swamp and rocky soils), including sites with high environmental sensibility. The services involved on pipeline implementation are very dynamic, involving several number of employees, vehicles, heavy equipment of excavation and welding that results in a high potential to cause environmental and social impacts. This article, based on the Brazilian and foreign experience on pipeline construction, proposes a methodology to prevent and minimize social and environmental impacts during the construction stage of a pipeline system. (author)

A novel approach to pipeline tensioner modeling

Energy Technology Data Exchange (ETDEWEB)

O' Grady, Robert; Ilie, Daniel; Lane, Michael [MCS Software Division, Galway (Ireland)

2009-07-01

As subsea pipeline developments continue to move into deep and ultra-deep water locations, there is an increasing need for the accurate prediction of expected pipeline fatigue life. A significant factor that must be considered as part of this process is the fatigue damage sustained by the pipeline during installation. The magnitude of this installation-related damage is governed by a number of different agents, one of which is the dynamic behavior of the tensioner systems during pipe-laying operations. There are a variety of traditional finite element methods for representing dynamic tensioner behavior. These existing methods, while basic in nature, have been proven to provide adequate forecasts in terms of the dynamic variation in typical installation parameters such as top tension and sagbend/overbend strain. However due to the simplicity of these current approaches, some of them tend to over-estimate the frequency of tensioner pay out/in under dynamic loading. This excessive level of pay out/in motion results in the prediction of additional stress cycles at certain roller beds, which in turn leads to the prediction of unrealistic fatigue damage to the pipeline. This unwarranted fatigue damage then equates to an over-conservative value for the accumulated damage experienced by a pipeline weld during installation, and so leads to a reduction in the estimated fatigue life for the pipeline. This paper describes a novel approach to tensioner modeling which allows for greater control over the velocity of dynamic tensioner pay out/in and so provides a more accurate estimation of fatigue damage experienced by the pipeline during installation. The paper reports on a case study, as outlined in the proceeding section, in which a comparison is made between results from this new tensioner model and from a more conventional approach. The comparison considers typical installation parameters as well as an in-depth look at the predicted fatigue damage for the two methods

Automatic welding detection by an intelligent tool pipe inspection

Science.gov (United States)

Arizmendi, C. J.; Garcia, W. L.; Quintero, M. A.

2015-07-01

This work provide a model based on machine learning techniques in welds recognition, based on signals obtained through in-line inspection tool called “smart pig” in Oil and Gas pipelines. The model uses a signal noise reduction phase by means of pre-processing algorithms and attribute-selection techniques. The noise reduction techniques were selected after a literature review and testing with survey data. Subsequently, the model was trained using recognition and classification algorithms, specifically artificial neural networks and support vector machines. Finally, the trained model was validated with different data sets and the performance was measured with cross validation and ROC analysis. The results show that is possible to identify welding automatically with an efficiency between 90 and 98 percent.

Process stability during fiber laser-arc hybrid welding of thick steel plates

Science.gov (United States)

Bunaziv, Ivan; Frostevarg, Jan; Akselsen, Odd M.; Kaplan, Alexander F. H.

2018-03-01

Thick steel plates are frequently used in shipbuilding, pipelines and other related heavy industries, and are usually joined by arc welding. Deep penetration laser-arc hybrid welding could increase productivity but has not been thoroughly investigated, and is therefore usually limited to applications with medium thickness (5-15 mm) sections. A major concern is process stability, especially when using modern welding consumables such as metal-cored wire and advanced welding equipment. High speed imaging allows direct observation of the process so that process behavior and phenomena can be studied. In this paper, 45 mm thick high strength steel was welded (butt joint double-sided) using the fiber laser-MAG hybrid process utilizing a metal-cored wire without pre-heating. Process stability was monitored under a wide range of welding parameters. It was found that the technique can be used successfully to weld thick sections with appropriate quality when the parameters are optimized. When comparing conventional pulsed and the more advanced cold metal transfer pulse (CMT+P) arc modes, it was found that both can provide high quality welds. CMT+P arc mode can provide more stable droplet transfer over a limited range of travel speeds. At higher travel speeds, an unstable metal transfer mechanism was observed. Comparing leading arc and trailing arc arrangements, the leading arc configuration can provide higher quality welds and more stable processing at longer inter-distances between the heat sources.

Orbital friction stir welding of aluminium pipes

International Nuclear Information System (INIS)

Engelhard, G.; Hillers, T.

2002-01-01

Friction stir welding (FSW) was originally developed for flat plates. This contribution shows how it can be applied to the welding of aluminium pipes. Pipes made of AlMG 3 (EN5754), AlMg 4.5Mn (EN5083) and AlMgSi 0.5 (EN6106) with dimensions of Da 600 and 520 x 10-8 mm were welded. The FSW orbital system comprises an annular cage with integrated FSW head, a hydraulic system, and a control unit. The welds were tested successfully according to EN 288. The mechanical and technical properties of the welds were somewhat better than with the TIG orbital process, and welding times were about 40 percent shorter [de

Ultrasonography X gamma radiography

International Nuclear Information System (INIS)

Mello Campos, A.M. de

1989-01-01

The accumulated experience in the last ten years of substitution to essays by gamma radiography to essay by ultrasonography, starting of the systematic comparison and tabulation of the results obtained by both essays applied in welding joints, in field, in steel pipelines of the SABESP. (V.R.B.)

Etude expérimentale du soudage par laser YAG de l'alliage base nickel Hastelloy X Experimental study of YAG laser welding of nickel base alloy Hastelloy X

Directory of Open Access Journals (Sweden)

Graneix Jérémie

2013-11-01

Full Text Available Le procédé de soudage laser YAG est envisagé pour remplacer le procédé de soudage TIG manuel pour la réalisation de pièces de turboréacteur en alliage nickel-chrome-molybdène Hastelloy X. Cette étude expérimentale a permis de définir un domaine de soudabilité de cet alliage répondant aux critères spécifiques du secteur aéronautique. The YAG laser welding process is contemplated to replace the manual TIG welding process for the production of parts of turbojet in Hastelloy X. This experimental study has identified the field of weldability of this alloy to meet the specific requirements of the aerospace industry.

Properties of welded joints of 2,25Cr-1Mo steel with various carbon content

International Nuclear Information System (INIS)

Vornovitskij, I.N.; Brodetskaya, E.Z.; Pozdnyakova, A.S.

1980-01-01

Properties of welded joints of 2,25 Cr - 1 Mo steel pipelines with different carbon content are considered. It is shown that application of electrodes developed in some countries for welding permits in many cases to exclude heat treatment of welded joints owing to high ductility of weld deposited metal. To improve the ductility, it is necessary to limit both carbon content down to 0,03-0,06% and detrimental elements (sulfur, phosphorus). Heat affected zone hardness may be increased at the expense of carbon. Weld deposited metal possesses the highest long-term strength at the given test temperature; in this case long-term strength of welded joints and base metal is practically the same. The long-term strength of high-carbon steel is higher at the test temperature of 565 deg C as compared to mean-carbon and low-carbon steels, whose long-term strength is practically equal at this temperature. The long-term strength of high-carbon and mean-carbon steels is practically the same and higher as compared with low-carbon one at the test temperature of 510 deg C

The Role of Hydrogen-Enhanced Strain-Induced Lattice Defects on Hydrogen Embrittlement Susceptibility of X80 Pipeline Steel

Science.gov (United States)

Hattori, M.; Suzuki, H.; Seko, Y.; Takai, K.

2017-08-01

Studies to date have not completely determined the factors influencing hydrogen embrittlement of ferrite/bainite X80 pipeline steel. Hydrogen embrittlement susceptibility was evaluated based on fracture strain in tensile testing. We conducted a thermal desorption analysis to measure the amount of tracer hydrogen corresponding to that of lattice defects. Hydrogen embrittlement susceptibility and the amount of tracer hydrogen significantly increased with decreasing crosshead speed. Additionally, a significant increase in the formation of hydrogen-enhanced strain-induced lattice defects was observed immediately before the final fracture. In contrast to hydrogen-free specimens, the fracture surface of the hydrogen-charged specimens exhibited shallower dimples without nuclei, such as secondary phase particles. These findings indicate that the presence of hydrogen enhanced the formation of lattice defects, particularly just prior to the occurrence of final fracture. This in turn enhanced the formation of shallower dimples, thereby potentially causing premature fracture of X80 pipeline steel at lower crosshead speeds.

The Exported Chaperone PfHsp70x Is Dispensable for the Plasmodium falciparum Intraerythrocytic Life Cycle.

Science.gov (United States)

Cobb, David W; Florentin, Anat; Fierro, Manuel A; Krakowiak, Michelle; Moore, Julie M; Muralidharan, Vasant

2017-01-01

Export of parasite proteins into the host erythrocyte is essential for survival of Plasmodium falciparum during its asexual life cycle. While several studies described key factors within the parasite that are involved in protein export, the mechanisms employed to traffic exported proteins within the host cell are currently unknown. Members of the Hsp70 family of chaperones, together with their Hsp40 cochaperones, facilitate protein trafficking in other organisms, and are thus likely used by P. falciparum in the trafficking of its exported proteins. A large group of Hsp40 proteins is encoded by the parasite and exported to the host cell, but only one Hsp70, P. falciparum Hsp70x (PfHsp70x), is exported with them. PfHsp70x is absent in most Plasmodium species and is found only in P. falciparum and closely related species that infect apes. Herein, we have utilized clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 genome editing in P. falciparum to investigate the essentiality of PfHsp70x. We show that parasitic growth was unaffected by knockdown of PfHsp70x using both the dihydrofolate reductase (DHFR)-based destabilization domain and the glmS ribozyme system. Similarly, a complete gene knockout of PfHsp70x did not affect the ability of P. falciparum to proceed through its intraerythrocytic life cycle. The effect of PfHsp70x knockdown/knockout on the export of proteins to the host red blood cell (RBC), including the critical virulence factor P. falciparum erythrocyte membrane protein 1 (PfEMP1), was tested, and we found that this process was unaffected. These data show that although PfHsp70x is the sole exported Hsp70, it is not essential for the asexual development of P. falciparum . IMPORTANCE Half of the world's population lives at risk for malaria. The intraerythrocytic life cycle of Plasmodium spp. is responsible for clinical manifestations of malaria; therefore, knowledge of the parasite's ability to survive within the erythrocyte is

Technology of electron beam welding for Zr-4 alloy spacer grid

International Nuclear Information System (INIS)

Pei Qiusheng; Wu Xueyi; Yang Qishun

1989-10-01

The welding technology for Zr-4 alloy spacer grid by using vacuum electron beam was studied. Through a series of welding technological experiments, metallographic examinations of seam structure and detecting tests for welding defect by X-ray defectoscopy, a good welding technology was selected to meet the requirements. The experimental results indicated that the Zr-4 alloy spacer grid welded by vacuum electron beam welding is feasible

Corrosion effect of Bacillus cereus on X80 pipeline steel in a Beijing soil environment.

Science.gov (United States)

Wan, Hongxia; Song, Dongdong; Zhang, Dawei; Du, Cuiwei; Xu, Dake; Liu, Zhiyong; Ding, De; Li, Xiaogang

2018-06-01

The corrosion of X80 pipeline steel in the presence of Bacillus cereus (B. cereus) was studied through electrochemical and surface analyses and live/dead staining. Scanning electron microscopy and live/dead straining results showed that a number of B. cereus adhered to the X80 steel. Electrochemical impedance spectroscopy showed that B. cereus could accelerate the corrosion of X80 steel. In addition, surface morphology observations indicated that B. cereus could accelerate pitting corrosion in X80 steel. The depth of the largest pits due to B. cereus was approximately 11.23μm. Many pits were found on the U-shaped bents and cracks formed under stress after 60days of immersion in the presence of B. cereus. These indicate that pitting corrosion can be accelerated by B. cereus. X-ray photoelectron spectroscopy results revealed that NH 4 + existed on the surface of X80 steel. B. cereus is a type of nitrate-reducing bacteria and hence the corrosion mechanism of B. cereus may involve nitrate reduction on the X80 steel. Copyright © 2018 Elsevier B.V. All rights reserved.

X-ray diffraction based residual stress analysis of repair welds of CrMo steels

International Nuclear Information System (INIS)

Rai, Sanjay; Sujith, S.; Jayakumar, T.

1996-01-01

Premature failure of weldments is often reported in the industry. Once failure occurs, the common practice now a days is either to replace the whole component or repair the failed region by welding. Since repairing rather than replacing is more economical, the process of repair welding assumes technological significance. However, it is necessary to realise the problems associated with repair-welding. During most of the repair welding cases, after repair weldments are hard and brittle. In many cases it is not possible to give post weld heat treatment (PWHT). This demands better welding techniques for repair without affecting the microstructure. Repair welding requires adoption of special procedure and parameters to obtain acceptable properties of the repair welded regions. In this paper different repair welding methods have been compared from residual stress and hardness point of view. (author)

Estudo do comportamento do aço API 5L X80 quando submetido à soldagem por processo automatizado Study on the behavior of API 5L X80 steel when subjected to automated welding process

Directory of Open Access Journals (Sweden)

Siderley Fernandes Albuquerque

2012-06-01

Full Text Available No Brasil, a soldagem de tubulações tem sido praticamente de forma manual, entretanto, a utilização de processos de soldagem automatizados têm crescido muito nos últimos anos, contribuindo para o maior controle dos parâmetros de soldagem, e conseqüentemente, a possibilidade de obtenção de juntas soldadas com melhores propriedades mecânicas. A soldagem de tubulações com aço API 5L X80 ainda vem sendo avaliada no Brasil no que diz respeito aos melhores procedimentos, parâmetros e processos de soldagem; a aplicação de processos automatizados nas condições específicas de campo constitui em uma opção ainda incipiente no país por se discutir ainda a relação custo/benefício com a sua implantação. Logo, o objetivo deste trabalho é avaliar o comportamento na ZTA de juntas soldadas do aço API 5L X80 utilizados para transporte de petróleo e gás quando submetidos à soldagem com diferentes parâmetros, procedimentos e processos de soldagem, incluindo o processo automatizado; os resultados indicam além da redução da extensão e do tamanho de grão da ZTA a preservação da estrutura bainítica do metal de base nesta região nas soldagem executadas com processos automatizados.The welding of pipes has been largely manual in Brazil, however, the use of automated welding processes have greatly increased in recent years, contributing to greater control of welding parameters, and consequently, the possibility of obtaining welded joints with better mechanical properties. The welding of pipes of API 5L X80 steel has been evaluated in Brazil considering to best practices, parameters and welding processes; the implementation of automated processes in the specific field conditions is relevant project and innovative design in this area. Therefore, the objective is to evaluate the behavior in the HAZ of the API 5L X80 steel used for transporting oil and gas when subjected to automated welding processes; the results indicated besides the

Critical Gap distance in Laser Butt-welding

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove

1999-01-01

In a number of systematic laboratory experiments the critical gap distance that results in sound beads in laser butt welding is sought identified. By grinding the edges of the sheets, a number of "reference" welds are made and compared to the sheets with shear cut edges. In the tests the gap...... was set at 0.00, 0.02, 0.05, 0.08 and 0.10 mm. Mild steel (St 1203) with a thickness of 0.75 and 1.25 mm with and without zinc coating were analysed. A total of 120 welds were made at different welding speeds.As quality norm DIN 8563 was used to divide the welds into quality classes. A number of welds...... were also x-ray photographed.Of the weld combinations analysed 80 % were of high quality and 17 % of a non-acceptable quality. 90 % of the bad welds had a gap distance larger than 0.05 mm. The results showed that 85 % of the bad welds were shear cut and only 15 % grinded. Two third of the bad welds...

Analysis of a multi pass weld of a thick walled tube made of austenitic stainless steel X6 CrNiNb 18 10

International Nuclear Information System (INIS)

Scholtes, B.; Zinn, W.; Ilg, U.; Backfisch, W.; Gibmeier, J.; Kirch, D.

2006-01-01

In this paper, microstructure and residual stresses of a multi pass welding of a thick-walled tube made of austenitic stainless steel X6 CrNiNb 18 10 (1.4550) are systematically characterized and assessed. Results of microstructural and phase analyses, residual stress and hardness measurements as well as of a tensile test using micro specimen and SEM analyses are presented. Using these data, plastic deformations occurring during the welding process in the vicinity of the weld seam are evaluated. Finally, consequences of an additional heat treatment at 400 C/24 h are studied. (Abstract Copyright [2006], Wiley Periodicals, Inc.) [de

Reliability analysis of land pipelines for hydrocarbons transportation in Mexico

Energy Technology Data Exchange (ETDEWEB)

Leon, D.; Cortes, C. [Inst. Mexicano del Petroleo (Mexico)

2004-07-01

The reliability of a land pipeline operated by PEMEX in Mexico was estimated under a range of failure modes. Reliability and safety were evaluated in terms of the pipeline's internal pressure, bending, fracture toughness and its tension failure mode conditions. Loading conditions were applied individually, while bending and tension loads were applied in a combined fashion. The mechanical properties of the steel were also considered along with the degradation effect of internal corrosion resulting from the type of product being transported. A set of internal pressures and mechanical properties were generated randomly using Monte Carlo simulation. Commercial software was used to obtain the pipeline response under each modeled condition. The response analysis was based on the nonlinear finite element method involving a calculation of maximum stresses and stress concentration factors under conditions of corrosion and no corrosion. The margin between maximum stresses due to internal pressure, tension and bending was evaluated along with the margin between stress concentration factor and fracture initiation toughness. The study showed that internal pressure, stress concentration and tension-bending were the critical failure modes. It was suggested that more research should be conducted to improve the modeling of the deteriorating effects of corrosion and to adjust the probability distribution for fracture toughness and the length/depth defect ratio. The consideration of welding geometries along with features of marine pipelines and pipeline products would help to generalize the study to facilitate the creation of codes for the construction, design, inspection and maintenance of pipelines in Mexico. 7 refs., 1 tab., 14 figs.

Welding of the A1 reactor pressure vessel

International Nuclear Information System (INIS)

Becka, J.

1975-01-01

As concerns welding, the A-1 reactor pressure vessel represents a geometrically complex unit containing 1492 welded joints. The length of welded sections varies between 10 and 620 mm. At an operating temperature of 120 degC and a pressure of 650 N/cm 2 the welded joints in the reactor core are exposed to an integral dose of 3x10 18 n/cm 2 . The chemical composition is shown for pressure vessel steel as specified by CSN 413090.9 modified by Ni, Ti and Al additions, and for the welding electrodes used. The requirements are also shown for the mechanical properties of the base and the weld metals. The technique and conditions of welding are described. No defects were found in ultrasonic testing of welded joints. (J.B.)

Characterization of Gas Metal Arc Welding welds obtained with new high Cr–Mo ferritic stainless steel filler wires

International Nuclear Information System (INIS)

Villaret, V.; Deschaux-Beaume, F.; Bordreuil, C.; Fras, G.; Chovet, C.; Petit, B.; Faivre, L.

2013-01-01

Highlights: • New metal cored filler wires for welding 444 grade stainless steel are manufactured. • The effect of Nb and Ti minor elements on the fusion zone properties is investigated. • The relation between composition of fusion zone and grain structure is investigated. • Oxidation rates of fusion zones and base metal are compared. • High temperature behavior of the welded samples are studied. - Abstract: Several compositions of metal cored filler wire were manufactured to define the best welding conditions for homogeneous welding, by Gas Metal Arc Welding (GMAW) process, of a modified AISI 444 ferritic stainless steel dedicated to automotive exhaust manifold applications. The patented grade is know under APERAM trade name K44X and has been developed to present improved high temperature fatigue properties. All filler wires investigated contained 19% Cr and 1.8% Mo, equivalent to the base metal K44X chemistry, but various titanium and niobium contents. Chemical analyses and microstructural observations of fusion zones revealed the need of a minimum Ti content of 0.15% to obtain a completely equiaxed grain structure. This structure conferred on the fusion zone a good ductility even in the as-welded state at room temperature. Unfortunately, titanium additions decreased the oxidation resistance at 950 °C if no significant Nb complementary alloying was made. The combined high Ti and Nb additions made it possible to obtain for the welded structure, after optimized heat treatment, high temperature tensile strengths and ductility for the fusion zones and assemblies, rather close to those of the base metal. 950 °C aging heat treatment was necessary to restore significantly the ductility of the as welded structure. Both fusion zone and base metal presented rather homogenized properties. Finally, with the optimized composition of the cored filler wire – 0.3 Ti minimum (i.e. 0.15% in the fusion zone) and high Nb complementary additions, the properties

Effect of nickel content on mechanical properties and fracture toughness of weld metal of WWER-1000 reactor vessel welded joints

International Nuclear Information System (INIS)

Zubchenko, A.S.; Vasilchenko, G.S.; Starchenko, E.G.; Nosov, S.I.

2004-01-01

Welding of WWER-1000 reactor vessel of steel 15X2HMPHIA is performed using the C B -12X2H2MAA wire and PHI-16 or PHI-16A flux. Nickel content in the weld metal usually lays within the limits 1.2-1.9%. The experimental data is shown on the weld metal with the nickel contents 1.28-2.45% after irradiation with fluence up to 260.10 22 n/m 2 at energy more than 0.5 MEV. The embrittlement was measured by shift of critical brittleness temperature. Has appeared, that the weld metal with the low nickel content is the least responsive to irradiation embrittlement. The mechanical properties and fracture toughness of the weld metal with the contents of a nickel less than 1.3% are studied. Specimens CT-1T are tested, the 'master-curve', and its confidence bounds with probability of destruction 5 and 95% is built. 'Master-curve' in the specified confidence interval is affirmed by CT-4T specimens test data. Is shown, that the mechanical properties and fracture toughness of the weld metal with the contents of nickel less than 1.3% satisfy the normative requirements

The Microstructure Evolution of Dual-Phase Pipeline Steel with Plastic Deformation at Different Strain Rates

Science.gov (United States)

Ji, L. K.; Xu, T.; Zhang, J. M.; Wang, H. T.; Tong, M. X.; Zhu, R. H.; Zhou, G. S.

2017-07-01

Tensile properties of the high-deformability dual-phase ferrite-bainite X70 pipeline steel have been investigated at room temperature under the strain rates of 2.5 × 10-5, 1.25 × 10-4, 2.5 × 10-3, and 1.25 × 10-2 s-1. The microstructures at different amount of plastic deformation were examined by using scanning and transmission electron microscopy. Generally, the ductility of typical body-centered cubic steels is reduced when its stain rate increases. However, we observed a different ductility dependence on strain rates in the dual-phase X70 pipeline steel. The uniform elongation (UEL%) and elongation to fracture (EL%) at the strain rate of 2.5 × 10-3 s-1 increase about 54 and 74%, respectively, compared to those at 2.5 × 10-5 s-1. The UEL% and EL% reach to their maximum at the strain rate of 2.5 × 10-3 s-1. This phenomenon was explained by the observed grain structures and dislocation configurations. Whether or not the ductility can be enhanced with increasing strain rates depends on the competition between the homogenization of plastic deformation among the microconstituents (ultra-fine ferrite grains, relatively coarse ferrite grains as well as bainite) and the progress of cracks formed as a consequence of localized inconsistent plastic deformation.

System-Enforced Deterministic Streaming for Efficient Pipeline Parallelism

Institute of Scientific and Technical Information of China (English)

张昱; 李兆鹏; 曹慧芳

2015-01-01

Pipeline parallelism is a popular parallel programming pattern for emerging applications. However, program-ming pipelines directly on conventional multithreaded shared memory is difficult and error-prone. We present DStream, a C library that provides high-level abstractions of deterministic threads and streams for simply representing pipeline stage work-ers and their communications. The deterministic stream is established atop our proposed single-producer/multi-consumer (SPMC) virtual memory, which integrates synchronization with the virtual memory model to enforce determinism on shared memory accesses. We investigate various strategies on how to efficiently implement DStream atop the SPMC memory, so that an infinite sequence of data items can be asynchronously published (fixed) and asynchronously consumed in order among adjacent stage workers. We have successfully transformed two representative pipeline applications – ferret and dedup using DStream, and conclude conversion rules. An empirical evaluation shows that the converted ferret performed on par with its Pthreads and TBB counterparts in term of running time, while the converted dedup is close to 2.56X, 7.05X faster than the Pthreads counterpart and 1.06X, 3.9X faster than the TBB counterpart on 16 and 32 CPUs, respectively.

Laser welding by dental Nd:YAG device

Science.gov (United States)

Fornaini, Carlo; Bertrand, Caroline; Merigo, Elisabetta; Bonanini, Mauro; Rocca, Jean-Paul; Nammour, Samir

2009-06-01

Welding laser was introduced in jewellery during years 70 and, just after, was successfully used also by dental technicians. Welding laser gives a great number of advantages, versus traditional welding and, for this reason, this procedure had a great diffusion in the technician laboratories and stimulated the companies to put in the market more and more evolutes appliances. Some aspects, such great dimensions, high costs and delivery system today still characterize these machines by fixed lenses, which have strictly limited its use only to technician laboratories. The aim of this study is to demonstrate the possibility, by using a fibber-delivered laser normally utilized in the dental office, to make, by dentist himself in his office, welding on different metals and to evaluate advantages and possibilities of this new technique.

Probabilistic Estimation of Critical Flaw Sizes in the Primary Structure Welds of the Ares I-X Launch Vehicle

Science.gov (United States)

Pai, Shantaram S.; Hoge, Peter A.; Patel, B. M.; Nagpal, Vinod K.

2009-01-01

The primary structure of the Ares I-X Upper Stage Simulator (USS) launch vehicle is constructed of welded mild steel plates. There is some concern over the possibility of structural failure due to welding flaws. It was considered critical to quantify the impact of uncertainties in residual stress, material porosity, applied loads, and material and crack growth properties on the reliability of the welds during its pre-flight and flight. A criterion--an existing maximum size crack at the weld toe must be smaller than the maximum allowable flaw size--was established to estimate the reliability of the welds. A spectrum of maximum allowable flaw sizes was developed for different possible combinations of all of the above listed variables by performing probabilistic crack growth analyses using the ANSYS finite element analysis code in conjunction with the NASGRO crack growth code. Two alternative methods were used to account for residual stresses: (1) The mean residual stress was assumed to be 41 ksi and a limit was set on the net section flow stress during crack propagation. The critical flaw size was determined by parametrically increasing the initial flaw size and detecting if this limit was exceeded during four complete flight cycles, and (2) The mean residual stress was assumed to be 49.6 ksi (the parent material s yield strength) and the net section flow stress limit was ignored. The critical flaw size was determined by parametrically increasing the initial flaw size and detecting if catastrophic crack growth occurred during four complete flight cycles. Both surface-crack models and through-crack models were utilized to characterize cracks in the weld toe.

X-ray and neutron diffraction determination of residual stresses in a pressed and welded component

International Nuclear Information System (INIS)

Albertini, G.; Broda, M.; Fiori, F.; Girardin, E.; Giuliani, A.; Quadrini, E.

1999-01-01

Complete text of publication follows. Problems connected with welding and pressing are very important in mechanical design, as these processed create microstructural alterations and internal stresses in the material that cannot be neglected. A pressing steel (FEP13) machine element is considered, designed to support a scooter engine. Two kinds of fatigue are to be supported by the component during operation: high loads at low frequency, due to the interaction of the scooter with the soil and low loads at high frequency due to the engine. The knowledge of the residual stress field occurring before operation is fundamental in order to perform theoretical predictions of the stress state during operation, and also to determine the loads to be used in fatigue tests which the component will be submitted to. The results of X-ray and neutron experiments are presented, carried out across a 'critical' weld in the component. (author)

Ultrasonic evaluation of friction stud welded AA 6063/AISI 1030 steel joints

International Nuclear Information System (INIS)

Hynes, N. Rajesh Jesudoss; Nagaraj, P.; Sujana, J. Angela Jennifa

2014-01-01

Highlights: • Friction stud welding of AA 6063 and AISI 1030 was done successfully. • Ultrasonic evaluation of interfacial properties. • EDX analysis confirms intermetallic compound (FeAl) in the interfacial region. - Abstract: Friction stud welding is a promising technique in many applications related to oil and gas industries. It is used to attach grating to offshore oil platforms in areas where arc welding is not permitted because of the risk of causing a fire or explosion. Attachment of anodes inside seawater discharge pipelines in a gas processing plant is performed by this process. This solid state joining process permits metal combinations such as welding of aluminum studs to steel which would be problematic with arc welding because of the formation of thick and brittle inter-metallic compounds. In the present work, AA 6063 is joined to AISI 1030 steel using friction stud welding machine. Properties that are of interest to manufacturing applications such as Young’s modulus, longitudinal velocity, bulk modulus and shear modulus are evaluated by means of an ultrasonic flaw detector. At the interface of the joint, there is an increase of 4.4%, 1.8%, 1.15% and 4.42% is observed for the properties Young’s modulus, longitudinal velocity, bulk modulus and shear modulus respectively. This is due to the formation of intermetallic compound and increase in hardness at the interfacial region. Energy Dispersive X-ray analysis confirms the presence of FeAl as the intermetallic compound. Scanning Electron Microscope evaluation shows the presence of an unbound zone at the center of the inner region which is due to the minimum rotational speed and low axial load experienced at that point. In the unbound zone, there is an incomplete bond between dissimilar metals and it is detrimental to joint strength. Optimum value of friction time and usage of pure aluminum interlayer during the friction stud welding process hinders the formation of unbound zone and enhances the

Real Structure and Resudal Stresses in Advanced Welds Determined by X-ray and Neutron Diffraction

Czech Academy of Sciences Publication Activity Database

Trojan, K.; Hervoches, Charles; Ganev, N.; Mikula, Pavol; Čapek, J.

2017-01-01

Roč. 9, SEP (2017), s. 32-38 E-ISSN 2336-5382 R&D Projects: GA MŠk LM2015056; GA ČR GB14-36566G Institutional support: RVO:61389005 Keywords : laser and MAG welding * residual stresses * X-ray diffraction * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) https://ojs.cvut.cz/ojs/index.php/APP/article/view/4401/4298

Unraveling the Processing Parameters in Friction Stir Welding

Science.gov (United States)

Schneider, Judy; Nunes, Arthur C., Jr.

2005-01-01

In friction stir welding (FSW), a rotating threaded pin tool is translated along a weld seam, literally stirring the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path or paths is required. In this study, various markers are used to trace the flow paths of the metal. X-ray radiographs record the segmentation and position of the wire. Several variations in the trajectories can be differentiated within the weld zone.

Corrosion of X65 Pipeline Steel Under Deposit and Effect of Corrosion Inhibitor

Directory of Open Access Journals (Sweden)

XU Yun-ze

2016-10-01

Full Text Available Effect of the deposit on the electrochemical parameters of X65 pipeline steel in oxygen contained sodium chloride solution was studied by EIS and PDS methods. The galvanic corrosion behavior under deposit and effect of different concentration of corrosion inhibitor PBTCA were studied by electrical resistance (ER method combined with ZRA. The results show that the corrosion potential of X65 steel shifts negatively as SiO2 covering its surface and the corrosion rate becomes lower. When the galvanic couple specimen with deposit is electrically connected with the specimen without deposit, anodic polarization occurs on X65 steel under deposit and the galvanic current density decreases from 120μA/cm2 to 50μA/cm2 and keeps stable. As 5×10-5, 8×10-5 and 3×10-4 PBTCA were introduced into the solution, the galvanic current density reaches the highest 1300μA/cm2 and then decreases to 610μA/cm2 keeping stable around 610μA/cm2, corrosion rate of X65 steel under deposit reaches 6.11mm/a. PBTCA accelerates the corrosion of X65 steel under deposit in oxygen contained solution. Through the investigation on the surface of the specimens, serious local corrosion occurs on the X65 steel surface under deposit.

Electron beam welding of heat exchangers

International Nuclear Information System (INIS)

Chergov, I.V.; Jarinov, V.I.; Minine, V.A.

1983-01-01

For a long time neither qualitative, nor quantitative criteria have been available that would have allowed choosing the most suitable welding techniques from the three stated below: 1) electron gun rotates relative to stationary tube; 2) electron beam is magnetically deviated relative to stationary tube; 3) permanent deviation magnet is rotated mechanically relative to stationary tube and gun. To our experience, the 2nd technique is most promising when welding 16x1.5 diameter stainless tubes. The e-b welds are vulnerable to root defects. With welding done in a movable manner, the root defect area will be found to locate in the tube plate body and, hence, the weldment, as a whole, will not be impaired [fr

The exported chaperone Hsp70-x supports virulence functions for Plasmodium falciparum blood stage parasites

Science.gov (United States)

Charnaud, Sarah C.; Dixon, Matthew W. A.; Nie, Catherine Q.; Chappell, Lia; Sanders, Paul R.; Nebl, Thomas; Hanssen, Eric; Berriman, Matthew; Chan, Jo-Anne; Blanch, Adam J.; Beeson, James G.; Rayner, Julian C.; Przyborski, Jude M.; Tilley, Leann; Crabb, Brendan S.

2017-01-01

Malaria is caused by five different Plasmodium spp. in humans each of which modifies the host erythrocyte to survive and replicate. The two main causes of malaria, P. falciparum and P. vivax, differ in their ability to cause severe disease, mainly due to differences in the cytoadhesion of infected erythrocytes (IE) in the microvasculature. Cytoadhesion of P. falciparum in the brain leads to a large number of deaths each year and is a consequence of exported parasite proteins, some of which modify the erythrocyte cytoskeleton while others such as PfEMP1 project onto the erythrocyte surface where they bind to endothelial cells. Here we investigate the effects of knocking out an exported Hsp70-type chaperone termed Hsp70-x that is present in P. falciparum but not P. vivax. Although the growth of Δhsp70-x parasites was unaffected, the export of PfEMP1 cytoadherence proteins was delayed and Δhsp70-x IE had reduced adhesion. The Δhsp70-x IE were also more rigid than wild-type controls indicating changes in the way the parasites modified their host erythrocyte. To investigate the cause of this, transcriptional and translational changes in exported and chaperone proteins were monitored and some changes were observed. We propose that PfHsp70-x is not essential for survival in vitro, but may be required for the efficient export and functioning of some P. falciparum exported proteins. PMID:28732045

The exported chaperone Hsp70-x supports virulence functions for Plasmodium falciparum blood stage parasites.

Directory of Open Access Journals (Sweden)

Sarah C Charnaud

Full Text Available Malaria is caused by five different Plasmodium spp. in humans each of which modifies the host erythrocyte to survive and replicate. The two main causes of malaria, P. falciparum and P. vivax, differ in their ability to cause severe disease, mainly due to differences in the cytoadhesion of infected erythrocytes (IE in the microvasculature. Cytoadhesion of P. falciparum in the brain leads to a large number of deaths each year and is a consequence of exported parasite proteins, some of which modify the erythrocyte cytoskeleton while others such as PfEMP1 project onto the erythrocyte surface where they bind to endothelial cells. Here we investigate the effects of knocking out an exported Hsp70-type chaperone termed Hsp70-x that is present in P. falciparum but not P. vivax. Although the growth of Δhsp70-x parasites was unaffected, the export of PfEMP1 cytoadherence proteins was delayed and Δhsp70-x IE had reduced adhesion. The Δhsp70-x IE were also more rigid than wild-type controls indicating changes in the way the parasites modified their host erythrocyte. To investigate the cause of this, transcriptional and translational changes in exported and chaperone proteins were monitored and some changes were observed. We propose that PfHsp70-x is not essential for survival in vitro, but may be required for the efficient export and functioning of some P. falciparum exported proteins.

Applied methodology for replacement pipe arcs in integral pipelines TE 'Oslomej'

Directory of Open Access Journals (Sweden)

Temelkoska Bratica K.

2016-01-01

Full Text Available The integral pipelines in thermal power plants present a linear spatial bearing construction with high operating parameters, complex static and dynamic load. The integral pipelines along its entire length are hanging on construction spring hangers from the boiler building, where the boiler is placed, next to the machine hall where the turbine is placed. Therefore, it is important to monitor the condition and to remove any possible defects from the applied methods. This paper describes the methodology of replacement of the pipe arch on one of the integral pipelines-the line for hot superheated steam. In addition, in this paper are given the method methods that led to this methodology for testing and evaluation of the condition of the pipe arch material that had been in exploitation and the new pipe arch that will be embedded. Furthermore the approach, the technology of replacement, anchoring of the steam line, technology of welding etc., as well as the preparation of the final design of constructed condition are also covered in this paper.

Phase formation and magnetic properties of YFe12-xNbx (x=0.70-0.90) compounds

International Nuclear Information System (INIS)

Fuquan, B.; Wang, J.L.; Tegus, O.; Dagula, W.; Tang, N.; Yang, F.M.; Wu, G.H.; Brueck, E.; Boer, F.R. de; Buschow, K.H.J.

2005-01-01

The phase formation and the magnetic properties of YFe 12-x Nb x (x=0.70-0.90) compounds have been investigated by means of X-ray diffraction and magnetization measurements. The powder X-ray diffraction patterns show that all compounds investigated crystallize single phase in the tetragonal ThMn 12 -type of structure. The lattice parameters and the unit-cell volume increase slightly with increasing Nb content, but the Curie temperature does not change. The X-ray-diffraction patterns of aligned powders of the samples show that all the compounds investigated have uniaxial anisotropy at room temperature. At 1.5K, the spontaneous magnetization, the anisotropy field and the anisotropy constant K 1 decrease with increasing Nb content

Use of fluorescent-metal intensifying screens with RT-type films for X-ray radiography using pulse devices

International Nuclear Information System (INIS)

Morgovskij, L.Ya.; Khakim'yanov, R.R.

1985-01-01

A study was made on characteristics of combination of fluorescent-metal Kyokko SMP-308 (Japan) and RCF (Agfa-Gevert) screens with domestic X-ray RT-1, RT-2, RT-5 films. Pulse X-ray MIRA-3D and NORA devices at 200 kV voltage amplitude in X-ray tube were used as radiation source. Testing was conducted for steel samples of 5-40 mm thickness. Comparative exposures for various film combinations with fluorescent-metal screens, fluorescent VP-2 screens and lead foils of 27 μm thickness were determined at that. It is shown that fluorescent-metal screens can be successfully applied with domestic X-ray technical films. They enable to decrease exposure by one order with insignificant deterioration of sensitivity. It is important for testing of pipeline welds

Failure Assessment for the High-Strength Pipelines with Constant-Depth Circumferential Surface Cracks

Directory of Open Access Journals (Sweden)

X. Liu

2018-01-01

Full Text Available In the oil and gas transportation system over long distance, application of high-strength pipeline steels can efficiently reduce construction and operation cost by increasing operational pressure and reducing the pipe wall thickness. Failure assessment is an important issue in the design, construction, and maintenance of the pipelines. The small circumferential surface cracks with constant depth in the welded pipelines are of practical interest. This work provides an engineering estimation procedure based upon the GE/EPRI method to determine the J-integral for the thin-walled pipelines with small constant-depth circumferential surface cracks subject to tension and bending loads. The values of elastic influence functions for stress intensity factor and plastic influence functions for fully plastic J-integral estimation are derived in tabulated forms through a series of three-dimensional finite element calculations for different crack geometries and material properties. To check confidence of the J-estimation solution in practical application, J-integral values obtained from detailed finite element (FE analyses are compared with those estimated from the new influence functions. Excellent agreement of FE results with the proposed J-estimation solutions for both tension and bending loads indicates that the new solutions can be applied for accurate structural integrity assessment of high-strength pipelines with constant-depth circumferential surface cracks.

Effect of nickel content on mechanical properties and fracture toughness of weld metal of WWER-1000 reactor vessel welded joints

Energy Technology Data Exchange (ETDEWEB)

Zubchenko, A.S.; Vasilchenko, G.S.; Starchenko, E.G.; Nosov, S.I

2004-08-01

Welding of WWER-1000 reactor vessel of steel 15X2HMPHIA is performed using the C{sub B}-12X2H2MAA wire and PHI-16 or PHI-16A flux. Nickel content in the weld metal usually lays within the limits 1.2-1.9%. The experimental data is shown on the weld metal with the nickel contents 1.28-2.45% after irradiation with fluence up to 260.10{sup 22}n/m{sup 2} at energy more than 0.5 MEV. The embrittlement was measured by shift of critical brittleness temperature. Has appeared, that the weld metal with the low nickel content is the least responsive to irradiation embrittlement. The mechanical properties and fracture toughness of the weld metal with the contents of a nickel less than 1.3% are studied. Specimens CT-1T are tested, the 'master-curve', and its confidence bounds with probability of destruction 5 and 95% is built. 'Master-curve' in the specified confidence interval is affirmed by CT-4T specimens test data. Is shown, that the mechanical properties and fracture toughness of the weld metal with the contents of nickel less than 1.3% satisfy the normative requirements.

The effect of initial stress induced during the steel manufacturing process on the welding residual stress in multi-pass butt welding

Directory of Open Access Journals (Sweden)

Jeong-ung Park

2018-03-01

Full Text Available A residual stress generated in the steel structure is broadly categorized into initial residual stress during manufacturing steel material, welding residual stress caused by welding, and heat treatment residual stress by heat treatment. Initial residual stresses induced during the manufacturing process is combined with welding residual stress or heat treatment residual stress, and remained as a final residual stress. Because such final residual stress affects the safety and strength of the structure, it is of utmost importance to measure or predict the magnitude of residual stress, and to apply this point on the design of the structure. In this study, the initial residual stress of steel structures having thicknesses of 25 mm and 70 mm during manufacturing was measured in order to investigate initial residual stress (hereinafter, referred to as initial stress. In addition, thermal elastic plastic FEM analysis was performed with this initial condition, and the effect of initial stress on the welding residual stress was investigated. Further, the reliability of the FE analysis result, considering the initial stress and welding residual stress for the steel structures having two thicknesses, was validated by comparing it with the measured results. In the vicinity of the weld joint, the initial stress is released and finally controlled by the weld residual stress. On the other hand, the farther away from the weld joint, the greater the influence of the initial stress. The range in which the initial stress affects the weld residual stress was not changed by the initial stress. However, in the region where the initial stress occurs in the compressive stress, the magnitude of the weld residual compressive stress varies with the compression or tension of the initial stress. The effect of initial stress on the maximum compression residual stress was far larger when initial stress was considered in case of a thickness of 25 mm with a value of 180�

Application of new GMAW welding methods used in prefabrication of P92 (X10CrWMoVNb9-2) pipe butt welds

Energy Technology Data Exchange (ETDEWEB)

Urzynicok, Michal [Boiler Elements Factory ' ZELKOT' , Koszecin (Poland); Kwiecinski, Krzysztof; Slania, Jacek [Instytut Spawalnictwa, Gliwice (Poland); Szubryt, Marian [TUEV Nord, Katowice (Poland)

2010-07-01

Welding of collector pipes, flat heads, dished ends and connector pipes performed with high temperature and creep-resistant steels most often has been performed using TIG process combined with MMA processes. Progress in MAG process and availability of high quality filler materials (solid wires) enables welding of the above connections also using this method. In order to prove its efficiency, this article presents the results of related tests. The range of tests was similar to that applied during the qualification of welding technology. The investigation also involved microscopic and fractographic examinations. The results reveal that welding with new methods such as GMAW is by no means inferior to a currently applied MMA method yet the time of the process is shorter by 50%. The article present the world's first known positive results in welding of P92 grade steel using GMAW welding method. (orig.)

A three-dimensional sharp interface model for self-consistent keyhole and weld pool dynamics in deep penetration laser welding

International Nuclear Information System (INIS)

Pang Shengyong; Chen Liliang; Zhou Jianxin; Yin Yajun; Chen Tao

2011-01-01

A three-dimensional sharp interface model is proposed to investigate the self-consistent keyhole and weld pool dynamics in deep penetration laser welding. The coupling of three-dimensional heat transfer, fluid flow and keyhole free surface evolutions in the welding process is simulated. It is theoretically confirmed that under certain low heat input welding conditions deep penetration laser welding with a collapsing free keyhole could be obtained and the flow directions near the keyhole wall are upwards and approximately parallel to the keyhole wall. However, significantly different weld pool dynamics in a welding process with an unstable keyhole are numerically found. Many flow patterns in the welding process with an unstable keyhole, verified by x-ray transmission experiments, were successfully simulated and analysed. Periodical keyhole collapsing and bubble formation processes are also successfully simulated and believed to be in good agreement with experiments. The mechanisms of keyhole instability are found to be closely associated with the behaviour of humps on the keyhole wall, and it is found that the welding speed and surface tension are closely related to the formation of humps on the keyhole wall. It is also shown that the weld pool dynamics in laser welding with an unstable keyhole are closely associated with the transient keyhole instability and therefore modelling keyhole and weld pool in a self-consistent way is significant to understand the physics of laser welding.

Virtual Welded - Joint Design Integrating Advanced Materials and Processing Technology

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhishang; Ludewig, Howard W.; Babu, S. Suresh

2005-06-30

Virtual Welede-Joint Design, a systematic modeling approach, has been developed in this project to predict the relationship of welding process, microstructure, properties, residual stress, and the ultimate weld fatique strength. This systematic modeling approach was applied in the welding of high strength steel. A special welding wire was developed in this project to introduce compressive residual stress at weld toe. The results from both modeling and experiments demonstrated that more than 10x fatique life improvement can be acheived in high strength steel welds by the combination of compressive residual stress from the special welding wire and the desired weld bead shape from a unique welding process. The results indicate a technology breakthrough in the design of lightweight and high fatique performance welded structures using high strength steels.

Manufacturing method for intragranular stress corrosion cracking-induced test specimen for stainless steel pipeline

International Nuclear Information System (INIS)

Futagawa, Kiyoshi.

1994-01-01

In a manufacturing step for intragranular stress corrosion cracking-induced for stainless steel pipelines, pipe are abutted against with each other and welded, and a heat affected portion is applied with a sensitizing heat treatment. Further, a crevice jig is attached near the heat affected portion at the inner surface of the pipe and kept in a chlorine ion added water under high temperature and high pressure at a predetermined period of time. If tap water is used instead of purified water for C.P.T. test in a step of forming sample of IGSCC (intergranular stress corrosion cracking), since the chlorine ion concentration in the tap water is relatively high, TGSCC (intragranular stress corrosion crackings caused in all of the samples. A heat input and an interlayer temperature are determined for the material of stainless pipe having a carbon content of more than 0.05% so that the welding residual stress on the inner surface is applied as tension. The condition for the heat treatment is determined as, for example, 500degC x 24hr, and the samples are kept under water at high temperature and high pressure applied with chlorine ions for 500 to 200hours. As a result, since samples of TGSCC can be formed by utilizing the manufacturing step for IGSCC, there is no requirement for providing devices for applying environmental factors separately. (N.H.)

Soldadura (Welding). Spanish Translations for Welding.

Science.gov (United States)

Hohhertz, Durwin

Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

Comparison of welding induced residual stresses austenitic and ferritic steel weld joints

International Nuclear Information System (INIS)

Rajkumar, K.V.; Arun Kumar, S.; Mahadevan, S.; Manojkumar, R.; Rao, B. Purna Chandra; Albert, Shaju K.; Murugan, S.

2015-01-01

X-ray diffraction (XRD) is a well established technique for measurement of residual stresses in components and is being widely used. In XRD technique, the distance between the crystallographic planes (d spacing) is measured from peak position (2è) at various ø angles, where ø is the angle between the normal to the sample and the bisector of the incident and diffracted beam. From the slope of sin2ø vs. d spacing plot, the residual stresses are arrived by assuming a plane stress model. Welding induced residual stresses is of high importance as it is a major cause of failure in components. Surface compressive stresses improve the fatigue strength, whereas tensile residual stresses tend to decrease the fatigue strength. The present study compares the residual stresses that develop in 3 mm thick SS 316 and P91 TIG weld joints using the XRD technique. This study is aimed at understanding the influence of shrinkage during cooling and the effect of phase transformation induced volume changes on residual stress development in these two steels. While the first effect is predominant in the SS 316 weld, both the effects are present in the P91 welds. Stress measurements on SS 316 and P91 were carried out using Cr Kâ (λ-2.0840 Å) and Cr Ká (λ-2.2896 Å) radiations respectively. Typical 'M' type stress profile was observed across the weld centre line in both the welds. The variation and similarities between the longitudinal stress profiles observed in these two weld joints would be discussed. (author)

Support system for welded part inspection using X-ray. Simplified inspection system which does not need skilled workers

International Nuclear Information System (INIS)

Suga, Yasuo

1995-01-01

X-ray radiography has the excellent ability for operation and recording, accordingly, it has been used widely in industrial fields, but for deciding the presence of defects and their kinds and shapes from X-ray films, skilled workers are required. Recently because of the shortage of skilled workers and the increase of inspection efficiency, the necessity of its automation increased. The images of the films of the X-ray inspection of welded part are photographed with a CCD camera, and these are taken in a personal computer as the image data, then image processing is applied to them, and defect images are extracted automatically. Further, the technique of displaying the images so that inspectors can recognize them easily is devised. These procedures were examined. The constitution of the system the way of thinking in developing the system, the acquiring of high contrast images, the emphasis of defect images, the elimination of noise the treatment of emphasizing nuclear defect images, the elimination of background and the extraction of defect images, the results of the processing and image display are reported. The order of processes, the kind of a filter used and so on can be changed according to the purpose, the kind of welding and the image quality of films. (K.I.)

Measurements of the residual stresses in the welded steel columns based on the x-ray diffraction method, 2

International Nuclear Information System (INIS)

Kaneta, Kiyoshi; Nishizawa, Hidekazu; Arashiyama, Masaki.

1982-01-01

In order to evaluate the applicability of two kinds of techniques of the X-ray stress analysis, namely, the standard sin 2 psi method and the newly developed phi-sin 2 psi method, bending tests have been performed. The test results have proved that the values of the stresses measured by means of the mechanical devices and of those measured by the two kinds of the X-ray techniques coincide each other. Then, these two methods have been applied to measure the surface residual stresses of the box-typed, welded steel columns and the following conclusions have been drawn. 1. The principal stress of the surface residural stresses is, in most cases, oriented to the rolled directions at the center of the steel plates, and it tends to rotate in the neighborhood of the heat affected zones. 2. Tensile residual stresses of a large magnitude have been observed in the direction parallel to the beads of the weld, and the moderate compressive residual stresses can be detected in the direction normal to the beads. (author)

Luminescent properties of stabled hexagonal phase Sr1-xBaxAl2O4:Eu2+ (x=0.37-0.70)

International Nuclear Information System (INIS)

Wu Qiaoli; Liu Zhen; Jiao Huan

2009-01-01

Stabled hexagonal phase Sr 1-x Ba x Al 2 O 4 :Eu 2+ (x=0.37-0.70) was prepared by solid-state method. Result revealed that the structure behavior of the SrAl 2 O 4 :Eu 2+ calcined at 1350 deg. C in a reducing atmosphere for 5 h strongly depended on the Ba 2+ concentration. With increasing Ba 2+ concentration, a characteristic hexagonal phase can be observed. When 37-70% of the strontium is replaced by barium, the structure of the prepared sample is pure hexagonal. Photoluminescence and excitation spectra of the samples with different x and doped with 2% Eu 2+ were investigated. Changes in the emission spectra were observed in the two different phases. The green emission at 505 nm from Eu 2+ was found to be quite strong in the hexagonal phase. The intensity and peak position of the green luminescence from Eu 2+ changed with increasing content of Ba 2+ . The strongest green emission was obtained from Sr 0.61 Ba 0.37 Al 2 O 4 :Eu 2+ . The decay characteristics of Sr 1-x Ba x Al 2 O 4 :Eu 2+ (x=0.37-0.70) showed that the life times also varied with the value of x. Furthermore, the emission colors and decay times varying with x could be ascribed to the variation of crystal lattice.

Development of thick wall welding and cutting tools for ITER

International Nuclear Information System (INIS)

Nakahira, Masataka; Takahashi, Hiroyuki; Akou, Kentaro; Koizumi, Koichi

1998-01-01

The Vacuum Vessel, which is a core component of International Thermonuclear Experimental Reactor (ITER), is required to be exchanged remotely in a case of accident such as superconducting coil failure. The in-vessel components such as blanket and divertor are planned to be exchanged or fixed. In these exchange or maintenance operations, the thick wall welding and cutting are inevitable and remote handling tools are necessary. The thick wall welding and cutting tools for blanket are under developing in the ITER R and D program. The design requirement is to weld or cut the stainless steel of 70 mm thickness in the narrow space. Tungsten inert gas (TIG) arc welding, plasma cutting and iodine laser welding/cutting are selected as primary option. Element welding and cutting tests, design of small tools to satisfy space requirement, test fabrication and performance tests were performed. This paper reports the tool design and overview of welding and cutting tests. (author)

Development of thick wall welding and cutting tools for ITER

Energy Technology Data Exchange (ETDEWEB)

Nakahira, Masataka; Takahashi, Hiroyuki; Akou, Kentaro; Koizumi, Koichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-04-01

The Vacuum Vessel, which is a core component of International Thermonuclear Experimental Reactor (ITER), is required to be exchanged remotely in a case of accident such as superconducting coil failure. The in-vessel components such as blanket and divertor are planned to be exchanged or fixed. In these exchange or maintenance operations, the thick wall welding and cutting are inevitable and remote handling tools are necessary. The thick wall welding and cutting tools for blanket are under developing in the ITER R and D program. The design requirement is to weld or cut the stainless steel of 70 mm thickness in the narrow space. Tungsten inert gas (TIG) arc welding, plasma cutting and iodine laser welding/cutting are selected as primary option. Element welding and cutting tests, design of small tools to satisfy space requirement, test fabrication and performance tests were performed. This paper reports the tool design and overview of welding and cutting tests. (author)

Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

Directory of Open Access Journals (Sweden)

Arman Abdullah

2014-01-01

Full Text Available Various cases of accidents involving microbiology influenced corrosion (MIC were reported by the oil and gas industry. Sulfate reducing bacteria (SRB have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP, and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDS were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 mm/yr for ATCC 7757. The Tafel plot recorded the corrosion rate of 0.3290 mm/yr for Sg. Ular SRB and 0.2500 mm/yr for Desulfovibrio vulgaris. The results showed that the consortia of isolated SRB were of comparable effects and features with the single ATCC 7757 strain.

The Malarial Exported PFA0660w Is an Hsp40 Co-Chaperone of PfHsp70-x.

Directory of Open Access Journals (Sweden)

Michael O Daniyan

Full Text Available Plasmodium falciparum, the human pathogen responsible for the most dangerous malaria infection, survives and develops in mature erythrocytes through the export of proteins needed for remodelling of the host cell. Molecular chaperones of the heat shock protein (Hsp family are prominent members of the exportome, including a number of Hsp40s and a Hsp70. PFA0660w, a type II Hsp40, has been shown to be exported and possibly form a complex with PfHsp70-x in the infected erythrocyte cytosol. However, the chaperone properties of PFA0660w and its interaction with human and parasite Hsp70s are yet to be investigated. Recombinant PFA0660w was found to exist as a monomer in solution, and was able to significantly stimulate the ATPase activity of PfHsp70-x but not that of a second plasmodial Hsp70 (PfHsp70-1 or a human Hsp70 (HSPA1A, indicating a potential specific functional partnership with PfHsp70-x. Protein binding studies in the presence and absence of ATP suggested that the interaction of PFA0660w with PfHsp70-x most likely represented a co-chaperone/chaperone interaction. Also, PFA0660w alone produced a concentration-dependent suppression of rhodanese aggregation, demonstrating its chaperone properties. Overall, we have provided the first biochemical evidence for the possible role of PFA0660w as a chaperone and as co-chaperone of PfHsp70-x. We propose that these chaperones boost the chaperone power of the infected erythrocyte, enabling successful protein trafficking and folding, and thereby making a fundamental contribution to the pathology of malaria.

Structural behaviour of a welded superalloy cylinder with internal pressure in a high temperature environment

International Nuclear Information System (INIS)

Udoguchi, T.; Nakanishi, T.

1981-01-01

Steady and cyclic creep tests with internal pressure were performed at temperatures of 800 to 1000 0 C on Hastelloy X cylinders with and without a circumferential Tungsten Inert Gas (TIG) welding technique. The creep rupture strength of the TIG welded cylinders was much lower than that of the non-welded cylinders whilst creep rupture strength reduction by the TIG technique was not observed in uniaxial creep tests. The reason for the low creep strength of welded cylinders is discussed and it is noted that the creep ductility of weld metal plays an essentially important role. In order to improve the creep strength of the TIG welded cylinder, various welding procedures with assorted weld metals were investigated. Some improvements were obtained by using welding techniques which had either Incoloy 800 or a modified Hastelloy X material as the filler metal. (U.K.)

Risk from transport of gas by pipeline ''kokui-perm''

International Nuclear Information System (INIS)

Yelokhin, A.

1998-01-01

Full text of publication follows: the length of gas pipelines in Russia is 142 thousands km, 62 % are pipelines of the large diameters. Annually on gas pipelines in Russia there are more than 70 large accidents, more than 50 % from them is accompanied by ignition of gas. The average ecological looses from accident is: destruction arable lands - 78 hectares; removing from consumption agricultural soils - 6,2 hectares; destruction forests - 47,5 hectares. In work the reasons of accidents on gas pipelines of different diameters are analyzed. So, for pipelines a diameter of 1220 mm by the reasons of accidents are: marriage of civil and erection works - 39, 1 %; outside corrosion - 35,9 %; mechanical damages - 9,4 %; defects of pipes - 6,2 %; defects of the factory equipment - 1,6 %; nature disasters and other reasons - 7,8 %. In work the results of risk analysis on a gas pipeline 'Kokui - Perm' are analysed. The gas pipeline 'Kokui - Perm' passes near 22 towns and countries, crosses 15 highways, 2 rail ways, 15 rivers. In work the concrete recommendations for management of risk and safety of the population are given. (author)

Depressurization of a spread of Brazil-Bolivia gas pipeline and the emergency repair of a weld crack in a instrument derivation at Campo Grande compression station; Despressurizacao de trecho do gasoduto Bolivia-Brazil para reparo emergencial de trinca em uma derivacao de instrumento de temperatura na Estacao de Compressao de Campo Grande - MS

Energy Technology Data Exchange (ETDEWEB)

Dietrich, Carlos Ribeiro; Leite Junior, Ismael Casano [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil)

2005-07-01

The purpose of this paper is to report the actions taken to repair a gas leak, at an original pressure of 100 kgf/cm{sup 2}, occurred due to a 1 1/2'' branch pipe weld crack, located on the 24'' Campo Grande - Mato Grosso do Sul Compression Station discharge pipe. This branch pipe was used to a thermo well installation and was submitted to an additional strength caused by thermo well vibration. The weld repair actions required an urgent depressurization of a 33 km spread of Bolivia-Brazil Pipeline in a timely manner, to avoid any negative impact in the operational schedule. (author)

Critical Gap distance in Laser Butt-welding

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove

of "reference" welds are made and compared to sheets with the edges shear cut. The gap distance is precisely controlled by inserting spacers between the sheets. In the tests the gap is set at 0.00, 0.02, 0.05, 0.08 and 0.10 mm. Mild steel (St 1203) with thickness? of 0.75 and 1.25 mm with and without zinc......When butt-welding metal sheets with high power lasers the gap distance between the sheets determine the final quality of the seam. In a number of systematic laboratory experiments the critical gap distance that results in sound beads is identified. By grinding the edges of the sheets, a number...... coating were analysed. A total of 120 welds are made at different welding speeds.As quality norm DIN 8563 is used to divide the welds into quality classes. Since this norm only deals with surface defects a number of welds are also x-ray photographed.According to DIN 8563 the welds have classes of either B...

Evaluation of the AISI 904L Alloy Weld Overlays Obtained by GMAW and Electro-Slag Welding Processes

Science.gov (United States)

Jorge, Jorge C. F.; Meira, O. G.; Madalena, F. C. A.; de Souza, L. F. G.; Araujo, L. S.; Mendes, M. C.

2017-05-01

The use of superaustenitic stainless steels (SASS) as an overlay replacement for nickel-based alloys can be an interesting alternative for the oil and gas industries, due to its lower cost, when compared to superalloys. Usually, the deposition is made with several welding passes by using conventional arc welding processes, such as gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW) processes. In this respect, electro-slag welding (ESW), which promotes high heat inputs and low dilution of the welds, can also be attractive for this application, as it provides a higher productivity, once only one layer is needed for the deposition of the minimum thickness required. The present work evaluates the behavior of an AISI 904L SASS weld overlay deposited on a carbon steel ASTM A516 Grade 70 by ESW and GMAW processes. Both as-welded and heat-treated conditions were evaluated and compared. A multipass welding by GMAW process with three layers and 48 passes was performed on 12.5 × 200 × 250 mm steel plates with average welding energy of 1.0 kJ/mm. For ESW process, only one layer was deposited on 50 × 400 × 400 mm steel plates with average welding energy of 11.7 kJ/mm. After welding, a post-weld heat treatment (PWHT) at 620 °C for 10 h was performed in half of the steel plate, in order to allow the comparison between this condition and the as-welded one. For both processes, the austenitic microstructure of the weld deposits was characterized by optical microscopy and scanning electron microscopy with electron backscatter diffraction. A low proportion of secondary phases were observed in all conditions, and the PWHT did not promote significant changes on the hardness profile. Martensite for GMAW process and bainite for ESW process were the microstructural constituents observed at the coarse grain heat-affected zone, due to the different cooling rates. For ESW process, no evidences of partially diluted zones were found. As a consequence of the microstructural

Initial Development in Joining of ODS Alloys Using Friction Stir Welding

Energy Technology Data Exchange (ETDEWEB)

Ren, Weiju [ORNL; Feng, Zhili [ORNL

2007-08-01

Solid-state welding of oxide-dispersion-strengthened (ODS) alloy MA956 sheets using friction stir welding (FSW) was investigated. Butt weld was successfully produced. The weld and base metals were characterized using optical microscopy, scanning electronic microscopy, transmission electronic microscopy, and energy dispersion x-ray spectrum. Microhardness mapping was also conducted over the weld region. Analyses indicate that the distribution of the strengthening oxides was preserved in the weld. Decrease in microhardness of the weld was observed but was insignificant. The preliminary results seem to confirm the envisioned feasibility of FSW application to ODS alloy joining. For application to Gen IV nuclear reactor heat exchanger, further investigation is suggested.

TomoWELD. Precise detection of weld defects; TomoWELD. Defekte in Schweissnaehten praezise erkennen

Energy Technology Data Exchange (ETDEWEB)

Walter, David [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

2016-06-15

Nuclear power plants are complex and technically elaborate systems whose aim is to produce electricity. They must meet the highest safety requirements. Within the reactors, nuclear reactions and radioactive transformations release energy which is used to evaporate water. The steam generated drives turbines that in turn are coupled with generators which convert the kinetic energy provided by the turbines into electrical energy. The process is easy to illustrate but difficult to control and requires technical equipment such as kilometre-long pipe systems. Austenitic steel is frequently used for this purpose because of its high strength and corrosion resistance. The individual pipe components are joined by welding. However, welds may contain hidden defects. Cracks, lack of fusion or pore nests that can remain undetected may have catastrophic consequences. Therefore, all welds in a nuclear power plant, without exception, must be checked. Approved non-destructive methods use ultrasound and X-ray. The technology developed at BAM is called TomoWELD. [German] Kernkraftwerke sind komplexe und technisch aufwendige Anlagen zur Gewinnung von Elektrizitaet. Sie muessen allerhoechsten Sicherheitsanspruechen genuegen. Die bei Kernreaktionen und radioaktiven Umwandlungen freiwerdende Energie wird genutzt, um Wasser zu verdampfen. Der Dampf treibt Turbinen an und die wiederum sind mit Generatoren gekoppelt, welche die durch die Turbinen bereitgestellte kinetische Energie in elektrische Energie umwandeln. Der Prozess laesst sich einfach darstellen, ihn zu steuern ist allerdings kompliziert und erfordert weitere technische Komponenten, wie beispielsweise kilometerlange Rohrleitungssysteme. Wegen seiner hohen Festigkeit sowie Korrosionsbestaendigkeit wird oft austenitischer Stahl dafuer verwendet. Gefuegt werden die einzelnen Rohrteile durch Schweissen. Doch Schweissnaehte koennen viele verborgene Defekte enthalten. Bleiben Risse, Bindefehler oder Porennester unentdeckt, kann das

Studies of diluted antiferromagnets MnxMg1-xTiO3 with x=0.55 and 0.70 by muon spin relaxation method

International Nuclear Information System (INIS)

Fukaya, A.; Ito, A.; Torikai, E.; Nishiyama, K.; Nagamine, K.

1997-01-01

Longitudinal fields μSR measurements have been performed in order to probe the spin dynamics in the diluted antiferromagnets Mn x Mg 1-x TiO 3 with x=0.70 and 0.55. In the x=0.70 sample which forms the antiferromagnetic long-range order, the static and fluctuating fields coexist at the muon stopping site below T N . On the other hand, in the x=0.55 sample which shows the spin-glass behavior, the local fields fluctuate rather fast even below T SG . We infer that this drastic change occurs when Mn x Mg 1-x TiO 3 transforms from an antiferromagnetic system to a spin-glass system by dilution

Fatigue behaviour of X70 steel in crude oil

Czech Academy of Sciences Publication Activity Database

Gajdoš, Lubomír; Šperl, Martin; Bystrianský, J.

2015-01-01

Roč. 49, č. 2 (2015), s. 243-246 ISSN 1580-2949 R&D Projects: GA ČR(CZ) GAP105/10/2052; GA TA ČR(CZ) TE02000162 Institutional support: RVO:68378297 Keywords : corrosion fatigue * S-N curve * X70 steel * crude oil * separated water Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.439, year: 2015 http://mit.imt.si/Revija/izvodi/mit152/gajdos.pdf

Mathematical Modeling of Optical Radiation Emission as a Function of Welding Power during Gas Shielded Metal Arc Welding.

Science.gov (United States)

Bauer, Stefan; Janßen, Marco; Schmitz, Martin; Ott, Günter

2017-11-01

Arc welding is accompanied by intense optical radiation emission that can be detrimental not only for the welder himself but also for people working nearby or for passersby. Technological progress advances continuously in the field of joining, so an up-to-date radiation database is necessary. Additionally, many literature irradiance data have been measured for a few welding currents or for parts of the optical spectral region only. Within this paper, a comprehensive study of contemporary metal active gas, metal inert gas, and cold metal transfer welding is presented covering optical radiation emission from 200 up to 2,700 nm by means of (spectro-) radiometric measurements. The investigated welding currents range from 70 to 350 A, reflecting values usually applied in industry. Based upon these new irradiance data, three mathematical models were derived in order to describe optical radiation emission as a function of welding power. The linear, exponential, and sigmoidal emission models depend on the process variant (standard or pulsed) as well as on the welding material (mild and stainless steel, aluminum). In conjunction with the corresponding exposure limit values for incoherent optical radiation maximum permissible exposure durations were calculated as a function of welding power. Typical times are shorter than 1 s for the ultraviolet spectral region and range from 1 to 10 s for visible radiation. For the infrared regime, exposure durations are of the order of minutes to hours. Finally, a validation of the metal active gas emission models was carried out with manual arc welding.

Emission of nanoparticles during friction stir welding (FSW) of aluminium alloys.

Science.gov (United States)

Gomes, J F; Miranda, R M; Santos, T J; Carvalho, P A

2014-01-01

Friction stir welding (FSW) is now well established as a welding process capable of joining some different types of metallic materials, as it was (1) found to be a reliable and economical way of producing high quality welds, and (2) considered a "clean" welding process that does not involve fusion of metal, as is the case with other traditional welding processes. The aim of this study was to determine whether the emission of particles during FSW in the nanorange of the most commonly used aluminum (Al) alloys, AA 5083 and AA 6082, originated from the Al alloy itself due to friction of the welding tool against the item that was being welded. Another goal was to measure Al alloys in the alveolar deposited surface area during FSW. Nanoparticles dimensions were predominantly in the 40- and 70-nm range. This study demonstrated that microparticles were also emitted during FSW but due to tool wear. However, the biological relevance and toxic manifestations of these microparticles remain to be determined.

Inhibition of the formation of intermetallic compounds in aluminum-steel welded joints by friction stir welding

Directory of Open Access Journals (Sweden)

Torres López, Edwar A.

2015-12-01

Full Text Available Formation of deleterious phases during welding of aluminum and steel is a challenge of the welding processes, for decades. Friction Stir Welding (FSW has been used in an attempt to reduce formation of intermetallic compounds trough reducing the heat input. In this research, dissimilar joint of 6063-T5 aluminum alloy and AISI-SAE 1020 steel were welded using this technique. The temperature of welded joints was measured during the process. The interface of the welded joints was characterized using optical microscopy, scanning and transmission electron microscopy. Additionally, composition measurements were carried out by X-EDS and DRX. The experimental results revealed that the maximum temperature on the joint studied is less than 360 °C. The microstructural characterization in the aluminum-steel interface showed the absence of intermetallic compounds, which is a condition attributed to the use of welding with low thermal input parameters.La unión de juntas aluminio-acero, sin la formación de fases deletéreas del tipo FexAly, ha sido, por décadas, un desafío para los procesos de soldadura. La soldadura por fricción-agitación ha sido empleada para intentar reducir el aporte térmico y evitar la formación de compuestos intermetálicos. Usando esta técnica fueron soldadas juntas disimilares de aluminio 6063-T5 y acero AISI-SAE 1020. La soldadura fue acompañada de medidas de temperatura durante su ejecución. La interfase de las juntas soldadas fue caracterizada utilizando microscopía óptica, electrónica de barrido y electrónica de transmisión. Adicionalmente fueron realizadas medidas puntuales X-EDS y DRX. Los resultados experimentales revelan que la temperatura máxima en la junta es inferior a 360 °C. La caracterización microestructural en la interfase aluminio-acero demostró la ausencia de compuestos intermetálicos, condición atribuida al uso de parámetros de soldadura con bajo aporte térmico.

Combined PIXE and X-ray SEM studies on time-resolved deposits of welding shop aerosols

International Nuclear Information System (INIS)

Barfoot, K.M.; Mitchell, I.V.; Verheyen, F.; Babeliowsky, T.

1981-01-01

Time-resolved deposits of welding shop air particulates have been obtained using a streak sampling system. PIXE analysis of these deposits, using 2 MeV protons, typically revealed the presence of a large number of elements, with many in the range Z = 11-30. Strong variations, up to three orders of magnitude, in the concentrations of several elements such as Al, Si and Fe as well as Zn, Na, K and Ca were found. The 2 h sampling resolution normally used was found to be insufficient to follow the short pollution episodes that regularly occur in a welding shop environment and so sampling with a 20 min resolution was used. The variation of elemental concentrations for different sampling times together with information on the physical nature of these air particulates, determined with a scanning electron microscope (SEM) and Si(Li) X-ray detector attachment, are presented. This type of information together with that obtained from the PIXE analysis is of importance industrial hygiene studies. The need to make corrections for partial filter clogging, based on air-flow rate monitoring, is discussed. (orig.)

Pipeline engineering

CERN Document Server

Liu, Henry

2003-01-01

PART I: PIPE FLOWSINTRODUCTIONDefinition and Scope Brief History of PipelinesExisting Major PipelinesImportance of PipelinesFreight (Solids) Transport by PipelinesTypes of PipelinesComponents of PipelinesAdvantages of PipelinesReferencesSINGLE-PHASE INCOMPRESSIBLE NEWTONIAN FLUIDIntroductionFlow RegimesLocal Mean Velocity and Its Distribution (Velocity Profile)Flow Equations for One-Dimensional AnalysisHydraulic and Energy Grade LinesCavitation in Pipeline SystemsPipe in Series and ParallelInterconnected ReservoirsPipe NetworkUnsteady Flow in PipeSINGLE-PHASE COMPRESSIBLE FLOW IN PIPEFlow Ana

Fatigue properties of X80 pipeline steels with ferrite/bainite dual-phase microstructure

Energy Technology Data Exchange (ETDEWEB)

Zhao, Zuo-peng [Key Lab of Metastable Materials Science & Technology and College of Materials Science & Engineering, Yanshan University, Qinhuangdao 066004 (China); Qiao, Gui-ying [Key Lab of Metastable Materials Science & Technology and College of Materials Science & Engineering, Yanshan University, Qinhuangdao 066004 (China); Key Lab of Applied Chemistry of Hebei Province and School of Environment and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); Tang, Lei [Key Lab of Applied Chemistry of Hebei Province and School of Environment and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); Zhu, Hong-wei; Liao, Bo [Key Lab of Metastable Materials Science & Technology and College of Materials Science & Engineering, Yanshan University, Qinhuangdao 066004 (China); Xiao, Fu-ren, E-mail: frxiao@ysu.edu.cn [Key Lab of Metastable Materials Science & Technology and College of Materials Science & Engineering, Yanshan University, Qinhuangdao 066004 (China)

2016-03-07

Fatigue properties are important parameters for the safety design and security evaluation of gas transmission pipelines. In this work, the fatigue life at different stresses of full-thickness X80 pipeline steel plates with a ferrite/bainite dual-phase microstructure was investigated using a MTS servo-hydraulic universal testing machine; the fatigue crack propagation rate was examined with CT specimens by using an INSTRON 8874 testing machine. Results indicate that fatigue life increases as maximum stress decreases; as the maximum stress decreases to the maximum operating stress (440 MPa), the fatigue life is approximately 4.2×10{sup 5} cycles. The fatigue crack of the full-thickness fatigue life specimens is generated at the surface of rolled steel plates and then the crack propagates and grows inward until a fracture is formed. During fatigue crack growth, a transitional turning point appears in the curve of da/dN with ΔK in the Paris region. The transitional turning point that divides the Paris region to two stages is approximately ΔK≅30 MPa m{sup 1/2}. The change in the growth rate (da/dN) is related to the variation of the crack path and in the fracture mode because of the possible microstructural sensitivity of fatigue crack propagation behavior. This study also discussed the effect of duple phase ferrite/bainite microstructure on fatigue crack initiation and propagation.

Fatigue properties of X80 pipeline steels with ferrite/bainite dual-phase microstructure

International Nuclear Information System (INIS)

Zhao, Zuo-peng; Qiao, Gui-ying; Tang, Lei; Zhu, Hong-wei; Liao, Bo; Xiao, Fu-ren

2016-01-01

Fatigue properties are important parameters for the safety design and security evaluation of gas transmission pipelines. In this work, the fatigue life at different stresses of full-thickness X80 pipeline steel plates with a ferrite/bainite dual-phase microstructure was investigated using a MTS servo-hydraulic universal testing machine; the fatigue crack propagation rate was examined with CT specimens by using an INSTRON 8874 testing machine. Results indicate that fatigue life increases as maximum stress decreases; as the maximum stress decreases to the maximum operating stress (440 MPa), the fatigue life is approximately 4.2×10"5 cycles. The fatigue crack of the full-thickness fatigue life specimens is generated at the surface of rolled steel plates and then the crack propagates and grows inward until a fracture is formed. During fatigue crack growth, a transitional turning point appears in the curve of da/dN with ΔK in the Paris region. The transitional turning point that divides the Paris region to two stages is approximately ΔK≅30 MPa m"1"/"2. The change in the growth rate (da/dN) is related to the variation of the crack path and in the fracture mode because of the possible microstructural sensitivity of fatigue crack propagation behavior. This study also discussed the effect of duple phase ferrite/bainite microstructure on fatigue crack initiation and propagation.

External coatings for buried pipelines - a project approach; Revestimento externo para dutos enterrados - uma abordagem de projeto

Energy Technology Data Exchange (ETDEWEB)

Nunes, Laerce de P.; Gomes, Luiz Paulo; Nunes, Alessandra de M. [IEC - Instalacoes e Engenharia de Corrosao Ltda., Rio de Janeiro, RJ (Brazil)

2005-07-01

The transport of liquid or gas fluids, such as water, fuel, chemical products, minerals, among others, through underground pipelines, is becoming more significant in the whole world, specially in Brazil, due to low cost, operational security and low physical interference at the surface. By the other hand, the ambient matters, the population's security in pipeline tracing and economic aspects lead to greater requirements in relation to the integrity of those installations. Corrosion is one of the most important causes of underground pipelines' deterioration and coating and cathodic protection are recommended to prevent it from occurring. However, both techniques must be considered in the pipeline project for it to be successful. At the present work the most important kinds of coating for underground pipelines are presented, as well as the applications, limitations, reference norms and the interface with the cathodic protection systems in relation to the efficiencies to be adopted and the expected performance. Is it also discussed the welded piping joints confection and the protection difficulties when the efficiencies are not corresponded to those foreseen in the cathodic protection systems project. (author)

Evaluation of welding by MIG in martensitic stainless steel

International Nuclear Information System (INIS)

Fernandes, M.A.; Mariano, N.A.; Marinho, D.H.C. Marinho

2010-01-01

This work evaluated structure's characterization and mechanical properties after the welding process of the stainless steel CA6NM. The employed welding process was the metal active gas with tubular wire. The control of the thermal cycle in the welding process has fundamental importance regarding the properties of the welded joint, particularly in the thermally affected zone. The mechanical properties were appraised through impact resistance tests and the hardness and microstructure through metallographic characterization and Ray-X diffraction. The parameters and the process of welding used promoted the hardness and toughness appropriate to the applications of the steel. Welding energy's control becomes an essential factor that can affect the temperature of carbide precipitation and the nucleation of the retained austenite in the in the region of the in the thermally affected zone. (author)

Designing of CK45 carbon steel and AISI 304 stainless steel dissimilar welds

OpenAIRE

Pouraliakbar,Hesam; Hamedi,Mohsen; Kokabi,Amir Hossein; Nazari,Ali

2014-01-01

Gas tungsten arc welding of CK45 and AISI304 stainless steel was performed through preparation of different types of samples using ER308L and ERNi-1 wires. Welded samples were studied by different techniques including optical metallography, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction, hardness measurements and impact test. It was observed that in the buttered specimen, the structure of the weld metal was completely austenitic wh...

Weld oxide formation on lean duplex stainless steel

Energy Technology Data Exchange (ETDEWEB)

Westin, E.M. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden)], E-mail: elin.westin@outokumpu.com; Olsson, C.-O.A. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Brinellvaegen 23, SE-100 44 Stockholm (Sweden)

2008-09-15

Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition.

Weld oxide formation on lean duplex stainless steel

International Nuclear Information System (INIS)

Westin, E.M.; Olsson, C.-O.A.; Hertzman, S.

2008-01-01

Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition

Active flux tungsten inert gas welding of austenitic stainless steel AISI 304

Directory of Open Access Journals (Sweden)

D. Klobčar

2016-10-01

Full Text Available The paper presents the effects of flux assisted tungsten inert gas (A-TIG welding of 4 (10 mm thick austenitic stainless steel EN X5CrNi1810 (AISI 304 in the butt joint. The sample dimensions were 300 ´ 50 mm, and commercially available active flux QuickTIG was used for testing. In the planned study the influence of welding position and weld groove shape was analysed based on the penetration depth. A comparison of microstructure formation, grain size and ferrit number between TIG welding and A-TIG welding was done. The A-TIG welds were subjected to bending test. A comparative study of TIG and A-TIG welding shows that A-TIG welding increases the weld penetration depth.

Residual stresses evaluation in a gas-pipeline crossing

Energy Technology Data Exchange (ETDEWEB)

Fonseca, Maria Cindra [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Almeida, Manoel Messias [COMPAGAS, Curitiba, PR (Brazil); Rebello, Joao Marcos Alcoforado [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Souza Filho, Byron Goncalves de [PETROBRAS, Rio de Janeiro, RJ (Brazil)

2009-07-01

The X-rays diffraction technique is a well established and effectiveness method in the determination of the residual and applied stresses in fine grained crystalline materials. It allows to characterize and to quantify the magnitude and direction of the existing surface stresses in the studied point of the material. The objective of this work is the evaluation of the surface stresses in a 10 in diameter Natural Gas Distribution Pipeline manufactured from API 5 L Gr B steel of COMPAGAS company, in a crossing with a Natural Gas Transportation Pipeline, in Araucaria-PR. This kind of evaluation is important to establish weather you have to perform a repositioning of one of the pipeline or not. The measurements had been made in two transversal sections of the pipe, the one upstream (170 mm of the external wall of the pipeline) and another one downstream (840 mm of the external wall of the pipeline). Each transversal section measurements where carried out in 3 points: 9 hours, 12 hours and 3 hours. In each measured point of the pipe surface, the longitudinal and transversal stresses had been measured. The magnitude of the surface residual stresses in the pipe varied of +180 MPa at the -210 MPa. The residual stress state on the surface of the points 12 hours region is characterized by tensile stresses and by compressive stresses in the points of 3 and 9 hours region. The surface residual stresses in gas-pipeline have been measured using X-ray diffraction method, by double exposure technique, using a portable apparatus, with Cr-K-alpha radiation. (author)

Microstructure and mechanical properties of friction stir welded and laser welded high entropy alloy CrMnFeCoNi

Science.gov (United States)