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.

Fracture Mechanics of Conventional and Narrow Groove Pulse Current Gas Metal Arc Welds of HSLA Steel

2012 ◽  
Vol 710 ◽  
pp. 451-456
Author(s):  
Ravi Ranjan Kumar ◽  
P. K. Ghosh
Keyword(s):  
Fracture Toughness ◽  
Weld Metal ◽  
Tensile Properties ◽  
Arc Welding ◽  
Hsla Steel ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
Compact Tension ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding

Mechanical and fracture properties of 20MnMoNi55 grade high strength low alloy (HSLA) steel welds have been studied. The weld joints were made using Gas Tungsten Arc Welding (GTAW), Shielded Metal Arc Welding (SMAW) and Pulse Gas Metal Arc Welding (P-GMAW) methods on conventional V-groove (V-Groove) and Narrow groove (NG-13). The base metal and weld metal were characterised in terms of their metallurgical, mechanical and fracture toughness properties by following ASTM procedures. The J-Integral fracture test was carried out using compact tension C(T) specimen for base and weld metal. The fracture toughness and tensile properties of welds have been correlated with microstructure. In conventional V-groove welds prepared by P-GMAW shows the improvement in initiation fracture toughness (JIC) as compared to the weld prepared by SMAW. Similar improvements in tensile properties have also been observed. This is attributed to reduction in co-axial dendrite content due to lower heat input during P-GMAW process as compared to SMAW. In the narrow groove P-GMA weld prepared at f value of 0.15 has shown relative improvement of JIC as compared to that of the weld prepared by SMAW process.

Strategies for Controlling Welding Fumes at the Source - A Review

2014 ◽  
Vol 592-594 ◽  
pp. 2539-2545 ◽  
Author(s):  
Sreejith Mohan ◽  
S.P. Sivapirakasham ◽  
P. Bineesh ◽  
K. K. Satpathy
Keyword(s):  
Arc Welding ◽  
Control Strategies ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Detailed Knowledge ◽  
Welding Fumes ◽  
Shielded Metal Arc Welding ◽  
Factors Affecting ◽  
Metal Arc Welding ◽  
New Research

Exposure to welding fumes and its related hazards has always been a matter of serious concern. The mass and composition of fumes from welding depends on several factors. A detailed knowledge of these factors is necessary for understanding the mechanism of fume formation and developing suitable control strategies. This paper gives a literature overview on the various factors affecting welding fumes and strategies for controlling it. The paper focus on types of welding process like Manual Metal Arc Welding (MMAW) or Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW), Flux Core Arc Welding (FCAW), Gas and Tungsten Arc Welding (GTAW). The research in the area of controlling fumes at the source has grown rapidly recently. Still, effective methods have hardly been explored. Improving arc stability by addition of materials with low ionization potential to the welding electrode lead to promising new research directions.

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.

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.

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 The Influence of the Welding Process on the Ultrasonic Inspection of 9%Ni Steel Pipe Circumferential Welded Joints

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 961
Author(s):  
João da Cruz Payão Filho ◽  
Elisa Kimus Dias Passos ◽  
Rodrigo Stohler Gonzaga ◽  
Daniel Drumond Santos ◽  
Vinicius Pereira Maia ◽  
...  
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Ultrasonic Inspection ◽  
Welding Process ◽  
Oil And Gas Industry ◽  
Co2 Injection ◽  
Shielded Metal Arc Welding ◽  
Scanning Angle ◽  
Metal Arc Welding

This work aims to compare the ultrasonic inspection of 9%Ni steel joints welded with the Gas Metal Arc Welding (GMAW) process and Shielded Metal Arc Welding (SMAW) process. These are the two most widely used processes used to weld pipes for CO2 injection units for floating production storage and offloading (FPSO) in the Brazilian oil and gas industry. The SMAW equipment is simple and portable, which is convenient for the FPSO; however, the GMAW process has the advantage of welding with high productivity. In this study we performed a numerical simulation using the software CIVA, 11th version, to analyze the behavior of ultrasonic longitudinal wave beams through GMAW and SMAW dissimilar weld joints. Ultrasonic tests were performed on calibration blocks drawn from both welded joints to evaluate the simulation results. The results are discussed with regard to the microstructure of the weld metal via electron backscatter diffraction (EBSD) analyses. The SMAW process presented better inspection performance than the GMAW process in terms of attenuation and dispersion effects. Although the SMAW had a better outcome, for both processes the configuration of 16 active elements and a scanning angle of 48° resulted in an optimized inspection of the entire joint.

Chemical pollutants in the respiratory zone of welders: Determination of concentrations and hazard analysis

Work ◽  
2020 ◽  
Vol 67 (3) ◽  
pp. 591-598
Author(s):  
Younes Mehrifar ◽  
Sara Karimi Zeverdegani ◽  
Masoud Rismanchian
Keyword(s):  
Occupational Exposure ◽  
Arc Welding ◽  
Hazard Analysis ◽  
Gas Metal Arc Welding ◽  
Respiratory Protection ◽  
Shielded Metal Arc Welding ◽  
Direct Reading ◽  
Cross Sectional ◽  
Metal Arc Welding ◽  
Welding Processes

BACKGROUND: Welding pollutants have potentially dangerous effects on the health of welders. Analysis of exposure risks is an appropriate method for industrial hygiene occupational exposure. OBJECTIVE: The present study aimed to determine the concentrations of exposure and risk evaluation of welders to fumes and gases in three common types of welding including Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW). METHODS: This cross-sectional study was carried out at a steel company. Samples were taken from manganese, chromium and nickel fumes with NIOSH 7300 method and for NO, NO2, CO and O3 gases using direct reading instruments. SQRCA method was used to assess the level of exposure risk. RESULTS: Our study showed that the highest and lowest concentrations of exposure to gases were observed in MIG and GTAW welding, respectively. Also, the highest and lowest concentrations of exposure to metals were observed in SMAW and GTAW processes, respectively. Mean exposure to M, Cr and Ni metals was 2.302, 3.195, and 1.241 mg/m3, respectively. Also, mean exposure to CO, NO, NO2 and O3 was 43.05, 27.88, 4.30, and 0.41 ppm, respectively. Results of risk analysis showed that O3, NO2 and Cr had high and very high risk levels in all welding processes. CONCLUSIONS: MIG and SMAW welders have a high occupational exposure to metal and toxic gases in welding. Preventive measures such as assessment of workplace air, installation of the ventilation systems, and providing appropriate respiratory protection devices for welders should be taken.

scholarly journals REPLACEMENT OF MANUAL GMAW WELDING BY FCAW SEMI-AUTOMATIC WELDING

2021 ◽  
Vol 2021 (2) ◽  
pp. 4342-4347
Author(s):  
MARIAN SIGMUND ◽  
◽  
TADEAS CICHA
Keyword(s):  
Carbon Steel ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Parameters ◽  
Automatic Welding ◽  
Cored Wire ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Welding Procedure ◽  
Welding Processes

The article describes a replacement and benefits between manual gas metal arc welding (GMAW) with solid wire and semi-automatic flux-cored arc welding (FCAW) with metal flux-cored wire for a specific application of a welded steel compensator used for connecting piping systems to form larger units. For the replacement of the technologies and improvement of the welding efficiency and productivity a specific type of carbon steel mounting insert, DN300 PN16, was selected. Since these pressure parts are subject to the directive 2014/68/EU, both the welding processes have to meet the same welding quality requirements. In particular, they are the welding procedure qualification report (WPQR) and the welder’s or welding operator’s qualification in accordance with valid European standards. Based on this requirement, a sample was selected so that it would cover the widest possible range of carbon steel mounting inserts produced. This article describes the whole experiment including the selection of the right equipment and filler material, finding the ideal welding parameters, and the subsequent qualification of the welding procedure and the operator with emphasis on the largest possible increase in the welding speed and productivity for these specific weldments.

scholarly journals Efeito do metal de adição na resistência ao desgaste por deslizamento de um aço estrutural soldado por GMAW

2019 ◽  
Vol 24 (3) ◽  
Author(s):  
Daniela Fátima Giarollo ◽  
Cíntia Cristiane Petry Mazzaferro ◽  
José Antônio Esmerio Mazzaferro
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Metal Base ◽  
Metal Arc Welding

RESUMO O objetivo do presente trabalho foi avaliar o efeito do metal de adição na soldagem, e das microestruturas resultantes, na resistência ao desgaste de juntas soldadas de um aço estrutural ASTM A242, que possui resistência à corrosão atmosférica e é utilizado na fabricação de vagões destinados ao transporte de minério. As amostras foram soldadas através do processo GMAW (Gas Metal Arc Welding), utilizando dois metais de adição que apresentam resistências mecânicas diferentes, AWS ER70S-6 e AWS ER80S-G. A resistência ao desgaste das amostras foi avaliada através de ensaios de microdesgaste por deslizamento linear recíproco, a seco e em uma solução contendo 0,05M NaCl, em três regiões da junta soldada: metal base (MB), metal de solda (MS) e zona afetada pelo calor de grãos grosseiros (ZAC-GG). Após a soldagem, foi observado um aumento nos valores médios de durezas do MS e da ZAC em relação à dureza inicial do metal base. Os resultados dos ensaios de microdesgaste mostraram que o MB apresentou a menor resistência ao desgaste, possivelmente devido à sua microestrutura, que facilitou o desgaste por deformação plástica. A ZAC-GG apresentou a maior resistência ao desgaste entre as três regiões analisadas. Comparando os ensaios realizados nas condições a seco e em solução foi observada uma redução nos valores de coeficiente de atrito quando adicionada uma solução ao sistema, e uma perda de volume das trilhas mais acentuada. Observou-se que a utilização do metal de adição de menor resistência mecânica produziu juntas soldadas com resistência ao desgaste comparável às juntas obtidas com o arame de maior resistência.

scholarly journals COMPARAÇÃO DA TAXA DE DEPOSIÇÃO DO ARAME SÓLIDO ER70S6, 1,2MM, NO PROCESSO GMAW (MAG), COM O ARAME TUBULAR E71T1, 1,2MM, NO PROCESSO FCAW NO AÇO ASTM A 36

2018 ◽  
Vol 1 (1) ◽  
pp. 28-41
Author(s):  
Merciane Miranda Vulcão ◽  
Marco Aurélio de Carvalho Silva ◽  
Edmilson Antonio Sarni ◽  
Maria Aparecida Bovério
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding

O presente artigo apresenta uma análise comparativa da taxa de deposição do arame sólido AWS A5.18 ER70S-6 e tubular AWS A5.20 E71T-1 respectivamente nos processos de soldagem Gás Metal Arc Welding (GMAW) na variante Metal Active Gás (MAG) e Flux Cored Arc Welding (FCAW). Atualmente ambos os arames são utilizados para soldagem a arco em juntas de aços comuns com baixo e médio teor de carbono, porém com um crescimento substancial no uso do tubular em relação ao sólido. O objetivo desta pesquisa foi comparar o processo de soldagem GMAW e FCAW com os arames maciço e tubular, verificando as três variáveis que podem ser analisadas como indicativos de produtividade em soldagem: fator de operação, taxa de deposição e tempo de soldagem. Neste estudo as soldas foram feitas na posição plana em chanfro em V, no aço carbono ASTM A-36 para o delineamento dos experimentos e, em seguida, análise da influência dos parâmetros: tensão, corrente e tempo de soldagem em ambos os processos. Como procedimentos metodológicos foram utilizadas a pesquisa bibliográfica e experimental, por meio de laboratório. Os resultados permitem concluir que a taxa de deposição foi superior para o arame ER70S-6 em relação ao arame E71T-1, em função da corrente elétrica, onde, é a fundamental variável para o aumento da taxa de deposição. Outra variável que se destacou na menor redução de tempo de soldagem, gerando, portanto, uma maior produtividade do processo FCAW em relação ao GMAW.

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