Development of Contemporary Welding Procedures for Heavy Wall Hot Tap Split Tee Longitudinal Seam Welds

2016 ◽  
Author(s):  
Mark Atkinson ◽  
Simon Slater
Keyword(s):  
Arc Welding ◽  
Full Range ◽  
Large Diameter ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Quality Issues ◽  
Large Diameter Pipes ◽  
Remedial Work ◽  
Non Destructive ◽  
Longitudinal Seam

Historically, the manual metal arc welding (MMA) process has been used for welding of full encirclement split tees on hot tap connections for gas transmission pipelines. The National Grid high pressure gas transmission network currently consists of pipelines up to and including 1219 mm outside diameter. The large diameter pipes require split tee assemblies up to 80 mm thick. The arc time to complete welding can be considerable and requires multiple welders to complete welding in one continuous operation. The qualification of a mechanised gas shielded flux cored arc welding (GSFCAW) procedure for welding the longitudinal seams on large diameter tee connections would realise significant operational and cost benefits over the MMA method. The equipment for mechanised field welding is readily available for a large number of applications across many industries. Recent advances in the technology suggest that a suitable mechanised procedure can be developed for the longitudinal weld seams of split tee assemblies. The primary aim of this project was to qualify a mechanised GSFCAW process and set of procedures in line with the National Grid specification for welding longitudinal seams of split tee assemblies. A comprehensive welding and test schedule was performed using 50 mm tee material. Welding was performed using the Firefly welding system in three positions, flat, overhead and horizontal to cover the full range of welding positions required for tee connections with either horizontal or vertical off-take branches. Based on the mechanical testing and non-destructive examination (NDE) results, the combination of process and consumables used in this project have been qualified in accordance with the National Grid specification. A number of quality issues were observed during welding and recommendations to address these have been identified. The travel speeds achieved using the GSFCAW process are up to twice those recorded when welding a similar size fitting using MMA. Even after considering the remedial work required to rectify quality issues, the overall welding times recorded using the GSFCAW process were lower than those recorded on a similar size fitting welded on site using the MMA process.

Application of Multiple Methods of NDT for the Evaluation of Welded Joints in a Steel Bridge ASTM-A-588

2019 ◽  
Vol 287 ◽  
pp. 8-12
Author(s):  
Héctor C. Terán ◽  
Oscar Arteaga ◽  
F.S. Alcocer ◽  
Richard R. Navas ◽  
Stalin P. Mena ◽  
...  
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Base Material ◽  
Steel Bridge ◽  
Shielded Metal Arc Welding ◽  
Destructive Testing ◽  
Final State ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Non Destructive

This work is based on making a comparison of different inspection methods of non-destructive testing (NDT), to detect porosity, bite, undercut, splash, overlap, slag, concavity, lack of fusion and damage to base material, in welds of shielded metal arc welding (SMAW) and flux-cored arc welding (FCAW), made on a steel bridge ASTM-A-588. The main application of non-destructive tests is to evaluate the final state of a welded joint in critical points, in addition the fundamental objective is to ensure that the established acceptance and rejection criteria are met rigorously. For which non-destructive techniques are analyzed, such as the visual testing of welding on the beams of a bridge of length 35000 mm, subsequently, tests of inspection by liquid penetrant were used, based on the AWS D1.5 standard to confirm the failures in welded joints in ABA webs, an ultrasonic is also carried out using an SIUI CTS 602 equipment, finally to issue an acceptance and rejection criterion as determined by ASTM E165 and ASTM E2544-09.

Measurement of Young’s Modulus and Shear Modulus of Some Structures Welded Using Flux Cored Wire by Vibration Tests

2014 ◽  
Vol 216 ◽  
pp. 151-156 ◽  
Author(s):  
Liviu Bereteu ◽  
Mircea Vodǎ ◽  
Gheorghe Drăgănescu
Keyword(s):  
Shear Modulus ◽  
Arc Welding ◽  
Natural Frequencies ◽  
Free Vibrations ◽  
Vibration Modes ◽  
Cored Wire ◽  
Flux Cored Arc Welding ◽  
Longitudinal Elastic Modulus ◽  
Vibration Tests ◽  
Non Destructive

The aim of this work was to determine by vibration tests the longitudinal elastic modulus and shear modulus of welded joints by flux cored arc welding. These two material properties are characteristic elastic constants of tensile stress respectively torsion stress and can be determined by several non-destructive methods. One of the latest non-destructive experimental techniques in this field is based on the analysis of the vibratory signal response from the welded sample. An algorithm based on Pronys series method is used for processing the acquired signal due to sample response of free vibrations. By the means of Finite Element Method (FEM), the natural frequencies and modes shapes of the same specimen of carbon steel were determined. These results help to interpret experimental measurements and the vibration modes identification, and Youngs modulus and shear modulus determination.

scholarly journals The State of the Art of Underwater Wet Welding Practice: Part 1

2021 ◽  
Vol 100 (4) ◽  
pp. 132-141
Author(s):  
EZEQUIEL CAIRES PEREIRA PESSOA ◽  
◽  
STEPHEN LIU
Keyword(s):  
Research And Development ◽  
Weld Metal ◽  
Arc Welding ◽  
Structural Steels ◽  
Friction Stir ◽  
Underwater Wet Welding ◽  
Class A ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Welding Processes

Developments in underwater wet welding (UWW) over the past four decades are reviewed, with an emphasis on the research that has been conducted in the last ten years. Shielded metal arc welding with rutile-based coated electrodes was established as the most applied process in the practice of wet welding of structural steels in shallow water. The advancements achieved in previous decades had already led to control of the chemical com-position and microstructure of weld metals. Research and development in consumables formulation have led to control of the amount of hydrogen content and the level of weld porosity in the weld metal. The main focus of research and development in the last decade was on weldability of naval and offshore structural steels and acceptance of welding procedures for Class A weld classification according to American Welding Society D3.6, Under-water Welding Code. Applications of strictly controlled welding techniques, including new postweld heat treatment procedures, allowed for the welding of steels with carbon equivalent values greater than 0.40. Classification societies are meticulously scrutinizing wet welding procedures and wet weld properties in structural steels at depths smaller than 30 m prior to qualifying them as Class A capable. Alternate wet welding processes that have been tested in previous decades — such as friction stir welding, dry local habitat, and gas metal arc welding —have not achieved great success as originally claimed. Al-most all of the new UWW process developments in the last decade have focused on the flux cored arc welding (FCAW) process. Part 1 of this paper covers developments in microstructural optimization and weld metal porosity control for UWW. Part 2 discusses the hydrogen pickup mechanism, weld cooling rate control, design, and qualification of consumables. It ends with a description of the advancements in FCAW applications for UWW.

Hexavalent Chromium Exposure Levels Resulting from Shipyard Welding

1998 ◽  
Vol 14 (04) ◽  
pp. 246-254
Author(s):  
Bhaskar Kura ◽  
Praveen Mookoni
Keyword(s):  
Hexavalent Chromium ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Task Group ◽  
Health Administration ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Exposure Levels ◽  
The Impact ◽  
Welding Processes

The Occupational Safety and Health Administration is expected to reduce permissible exposure limits of hexavalent chromium from 100 ng/m3between 5 to 0.5 fig/m3. A Navy Industry Task Group study revealed that the impact of proposed regulations on the shipbuilding industry is significant. The estimated cost of compliance by the Navy facilities could be as much as $46 Million/year besides a one-time cost of about $22 Million. Also, the task group estimated that the cost of $9 Million. This paper presents the results of a study undertaken at the University of New Orleans in support of the Navy/Industry Task Group efforts. The study included assessments of Cr(VI) exposure levels for two specific welding processes and three welding scenarios. Airborne particulate matter was collected using personal samplers for two specific welding processes, Gas Metal Arc Welding and Flux-Cored Arc Welding. Two base metals, HY100 and DH36, were considered for Flux-Cored Arc Welding and one base metal, HY100, was considered for Gas Metal Arc Welding. The samples were analyzed for Cr(VI) using OSHA Method 215. Based on the data generated, it can be concluded that Gas Metal Arc Welding and Flux-Cored Arc Welding on HY100 steel result in 8-hr. worker exposures less than 0.5 fig/m3 in a laboratory type setting, though the same levels of exposure may be difficult to be achieved in the field. Flux-Cored Arc Welding on DH36 resulted in exposure above 0.5 ng/m3, again in laboratory type setting.

EDDY-CURRENT NON-DESTRUCTIVE TESTING OF LARGE-DIAMETER PIPES

2016 ◽  
pp. 20-25
Author(s):  
A.G. Efimov ◽  
A.E. Shubockin ◽  
E.V. Martyanov ◽  
P.N. Mefodichev
Keyword(s):  
Eddy Current ◽  
Large Diameter ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Large Diameter Pipes ◽  
Non Destructive

scholarly journals Fume Generation Behaviors in Short Circuit Mode during Gas Metal Arc Welding and Flux Cored Arc Welding

2006 ◽  
Vol 47 (7) ◽  
pp. 1859-1863 ◽  
Author(s):  
Hyunbyung Chae ◽  
Cheolhee Kim ◽  
Jeonghan Kim ◽  
Sehun Rhee
Keyword(s):  
Arc Welding ◽  
Short Circuit ◽  
Gas Metal Arc Welding ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding

scholarly journals Efecto del procedimiento de soldadura sobre las propiedades de uniones soldadas de aceros microaleados para cañería

2009 ◽  
Vol 14 (1) ◽  
pp. 36-46
Author(s):  
Mónica Zalazar ◽  
N. Mabel Ramini de Rissone ◽  
Estela S. Surian ◽  
Roberto Bruna ◽  
Esteban Baralla
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Shielded Metal Arc Welding ◽  
Metal Base ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding

El objetivo del trabajo fue, en esta primera etapa, comparar las propiedades mecánicas y la microestructura del acero HIC, aleado al Nb-Ti-Cu-Ni, resistente a la corrosión, con las del acero normal NOR, microaleado con Nb-V-Ti, ambos caracterizados mediante análisis químico, mediciones de dureza, estudios metalográficos y ensayos de tracción e impacto. Con el fin de establecer la temperatura de precalentamiento óptima se realizaron ensayos de soldabilidad Tekken a distintas temperaturas y de acuerdo con la Norma JIS Z 3158. Luego se llevaron a cabo soldaduras circunferenciales de cañerías fabricadas con ambos aceros diseñándose procedimientos para la utilización, por un lado, de electrodos revestidos (SMAW: shielded metal arc welding, electrodos de distintos proveedores) para todas las pasadas y por el otro, la primera pasada usando soldadura automática con alambre macizo bajo CO2 (GMAW: gas metal arc welding) y el resto de las mismas con alambre tubular autoprotegido (FCAW-S: flux cored arc welding-selfshielded). Las soldaduras fueron calificadas de acuerdo con el Código API 1104. Los resultados de los análisis metalográficos y los ensayos mecánicos de tracción, dureza e impacto de las juntas soldadas revelaron la influencia de los consumibles de soldadura y del metal base en las propiedades de las uniones. Se observaron diferencias en las propiedades de las uniones soldadas con consumibles de igual especificación y distintos proveedores. De las diferentes combinaciones ensayadas se definieron valores óptimos para la soldadura de estos aceros.

To the Question of Determining the Plasticity Zones of a Welded Joint of Large Diameter Pipes

2015 ◽  
Vol 763 ◽  
pp. 92-96
Author(s):  
Yuriy Ivanovich Pashkov ◽  
Mikhail Alekhsandrovich Ivanov ◽  
Yuriy Viktorovich Bezgans ◽  
Tatyana Vladimirovna Bezgans
Keyword(s):  
Plastic Deformation ◽  
Welded Joints ◽  
Arc Welding ◽  
Welded Joint ◽  
Large Diameter ◽  
Hydraulic Press ◽  
Welding Wire ◽  
Pipe Joints ◽  
Large Diameter Pipes ◽  
Welded Pipe

There was performed the analysis of a set of methodical solutions for determining of current and limit plasticity of welded joint zones at large diameter pipes. To determine the current plastic deformation of zones of pipes' welded joints it is offered to test the natural ring of a height of 80 mm, of a pipe with size 530x7,5 mm made of steel 17GS, welded by arc welding using a welding wire SV-08HM under a layer of flux AN-60. The ring samples are tested in the cone, the constructive dimensions of which match the cone used on the expander by the definite value of broadening on the hydraulic press with the force not less than 500 tons. The results of tests of ring samples of welded pipe with size 530х7,5 mm while their broadening by the cone. To determine the limit of plastic deformation of zones of a welded joint of large diameter pipes a method for testing a flat sample is proposed. The construction of the sample and the scheme of loading to determine the limit plasticity of welded pipe joints are proposed.

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