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

Short Circuit Severity Model for Pulse Gas Metal Arc Welding of Aluminum

2008 ◽  
Vol 580-582 ◽  
pp. 451-454 ◽  
Author(s):  
P. Praveen ◽  
K.D.V. Yarlagadda Prasad ◽  
M.J. Kang ◽  
Se Hun Rhee
Keyword(s):  
Experimental Data ◽  
Regression Model ◽  
Arc Welding ◽  
Short Circuit ◽  
Gas Metal Arc Welding ◽  
Multiple Regression Model ◽  
Optimization Techniques ◽  
Metal Arc Welding ◽  
Complete Automation ◽  
Good Agreement

Wide use of robotic machines for welding has necessitated the development of optimization techniques to achieve complete automation. The objective of the present study is to develop multiple regression model for quantitatively estimating the severity of the short circuit in pulse gas metal arc welding (GMAW-P) of aluminum, based on experimental results. The model results were found to be in good agreement with the experimental data and yielded satisfactory results.

Influence of Preset Pulsed Magnetic Field on Process Stability of Short Circuiting Transfer in Gas Metal Arc Welding

2011 ◽  
Vol 339 ◽  
pp. 440-443 ◽  
Author(s):  
Shu Jun Chen ◽  
Chang Hui Liu ◽  
Yang Yu ◽  
Shao Jun Bai
Keyword(s):  
Magnetic Field ◽  
Arc Welding ◽  
Short Circuit ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Pulsed Magnetic Field ◽  
Optimum Conditions ◽  
Horizontal Magnetic Field ◽  
Metal Arc Welding ◽  
Peak Value

This study proposed preset pulsed magnetic field acting on process of the short circuiting transfer. It is a controlled horizontal magnetic field which attached at the very beginning of contact between the wire and the weld pool during welding. It was found that there exists optimum conditions of magnetic field with which preset pulsed magnetic field could accelerate the rupture of the liquid bridge and reduce the peak value of welding current in the period of short circuiting transfer. This lead to energy accumulation lowered at the last phase of the short circuiting transfer and spatter loss reduced resulting from explosive short circuit rupture, in the meantime, it could improve the regularity and stability of the short circuiting transfer as well as the weld shaping quality.

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 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.

Evaluation of the sound signal based on the welding current in the gas—metal arc welding process

2003 ◽  
Vol 217 (5) ◽  
pp. 483-494 ◽  
Author(s):  
M Čudina ◽  
J Prezelj
Keyword(s):  
Arc Welding ◽  
Short Circuit ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Welding Current ◽  
Sound Signal ◽  
Frequency Noise ◽  
Metal Arc Welding ◽  
Arc Welding Process ◽  
Good Agreement

In this paper sound generated during the gas-metal arc welding process in the short-circuit mode was studied. Theoretical and experimental analyses of the acoustic signals have shown that there are two main noise-generating mechanisms. The first mechanism generating characteristic sound impulses is arc extinction and arc ignition; the second noise-generating mechanism is the arc itself, which acts as an ionization sound source and produces mainly high-frequency noise of a low level. The sound signal is used for assessing and monitoring the welding process and for prediction of welding process stability and quality. A new algorithm based on the measured welding current was established for the calculation of emitted sound during the welding process. The algorithm was verified for different supply voltages and for different welding materials. The comparisons have shown that the calculated values are in good agreement with measured values of the sound signal.

scholarly journals A New Approach to Simulate HSLA Steel Multipass Welding through Distributed Point Heat Sources Model

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 951 ◽  
Author(s):  
Dario Ferreira ◽  
Antonio Alves ◽  
Rubelmar Cruz Neto ◽  
Thiago Martins ◽  
Sérgio Brandi
Keyword(s):  
Arc Welding ◽  
Short Circuit ◽  
Hsla Steel ◽  
Gas Metal Arc Welding ◽  
Evaluation Criteria ◽  
External Diameter ◽  
Heat Sources ◽  
Temperature Dependent ◽  
Multipass Welding ◽  
Flux Cored Arc Welding

Mechanical properties of welded joints depend on the way heat flows through the welding passes. In multipass welding the reheating of the heat affected zone (HAZ) can form local brittle zones that need to be delimited for evaluation. The difficulty lies in the choice of a model that can simulate multipass welding. This study evaluated Rosenthal’s Medium Thick Plate (MTP) and the Distributed heat Sources (DHS) of Mhyr and Gröng models. Two assumptions were considered for both models: constant and temperature-dependent physical properties. It was carried out on a multipass welding of an API 5L X80 tube, with 1016 mm (42″) external diameter, 16 mm thick and half V-groove bevel, in the 3G up position. The root pass was welded with Gas Metal Arc Welding (GMAW) process with controlled short-circuit transfer. The Flux Cored Arc Welding (FCAW) process was used in the filling and finishing passes, using filler metal E111T1-K3M-JH4. The evaluation criteria used were overlapping the simulated isotherms on the marks revealed in the macrographs and the comparison between the experimental thermal cycle and those simulated by the proposed models. The DHS model with the temperature-dependent properties presented the best results and simulated with accuracy the HAZ of root and second welding passes. In this way, it was possible to delimit the HAZ heated sub-regions.

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