scholarly journals Influence of Gravity on Molten Pool Behavior and Analysis of Microstructure on Various Welding Positions in Pulsed Gas Metal Arc Welding

2019 ◽  
Vol 9 (21) ◽  
pp. 4626 ◽  
Author(s):  
Jin-Hyeong Park ◽  
Sung-Hwan Kim ◽  
Hyeong-Soon Moon ◽  
Myung-Hyun Kim
Keyword(s):  
Weld Metal ◽  
Arc Welding ◽  
Molten Pool ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
High Speed Camera ◽  
Shielding Gas ◽  
Metal Arc Welding ◽  
The One

This study performed welding on various welding positions in the flat, overhead, and vertical down positions using a pulsed gas metal arc welding (P-GMAW) process. Despite the same amount of heat input on various welding positions, the welding characteristics varied depending on the welding positions. The effect of gravity on the welding process determined the different formation of the weld bead, and the influence of molten pool behavior on various welding positions changed the microstructure in the weld metal. The current and voltage signals were synchronized with a high-speed camera using a data acquisition (DAQ) system. To induce the one pulse one drop (OPOD) process of metal transfer, the shielding gas was used 95% Ar+5% CO2. The microstructure of the weld metal was analyzed in relation to molten pool behavior.

An Evaluation System of Pulsed GMAW Process

2013 ◽  
Vol 483 ◽  
pp. 599-602
Author(s):  
Ying Gao ◽  
Jing Hua Han ◽  
Li Yan Lou ◽  
Huan Li
Keyword(s):  
Arc Welding ◽  
Evaluation System ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Electric Signal ◽  
Characteristic Parameters ◽  
Display Module ◽  
Metal Arc Welding ◽  
Labview Platform

A process evaluation system for pulsed gas metal arc welding (GMAW-P) based on the LabVIEW platform has been developed. This system is comprised of two modules, a simultaneous display module and a data analysis module. Using these modules, the system can not only provide a comprehensive direct viewing display of the welding electric signal and high speed camera photo, but also can analyze the characteristic parameters of the welding process. The results show that the system works properly.

Arc Interruptions in Tandem Pulsed Gas Metal Arc Welding

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Ruham Pablo Reis ◽  
Daniel Souza ◽  
Demostenes Ferreira Filho
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Electrical Current ◽  
Gas Tungsten Arc ◽  
Metal Arc Welding ◽  
Two Factors ◽  
Single Arc ◽  
Mean Current

In addition to electromagnetic attraction between the arcs in Tandem Pulsed gas metal arc welding (GMAW), arc interruptions, mostly in the trailing arc at low mean current levels, may also occur, which is a phenomenon not widely discussed in the welding field. These arc interruptions must be avoided, since they also represent interruptions in metal fusion and deposition during the welding process, leading to lack of fusion/penetration and/or deposition flaws, adding cost for repairing operations. To improve the understanding on arc interruptions in Tandem Pulsed GMAW and how the current pulsing synchronism between the arcs relates to this phenomenon, this work proposes to evaluate the influence of parameters of adjacent arcs (Tandem Pulsed GMAW) and also of a single arc (GTAW—gas tungsten arc welding), but similarly subjected to magnetic deflection, on the occurrence of arc interruptions/extinctions. High-speed filming was used to help understand the interruption/extinction mechanism. In the case of Tandem Pulsed GMAW, the pulses of current of the leading and trailing arcs need to be almost-in-phase to prevent interruptions in the trailing arc. The distance of 10 mm between the adjacent arcs helped reduce the incidence of trailing arc interruptions, yet keeping a sound weld visual quality. In the case of GTAW, the higher the electrical current flowing through the arcs and the shorter their lengths, the more they resist to the extinction. The trailing arc interruptions in Tandem Pulsed GMAW seem to be determined by the deflection and heat in this arc, and their prevention can be achieved by a balance between these two factors, which is reached by synchronized pulsing currents.

Effect of Gas Metal Arc Welding Parameters on Mechanical Properties for Carbon Steel ASTM A285 Grade A

2011 ◽  
Vol 341-342 ◽  
pp. 16-20
Author(s):  
Mongkol Chaisri ◽  
Prachya Peasura
Keyword(s):  
Carbon Dioxide ◽  
Tensile Strength ◽  
Carbon Steel ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Welding Parameters ◽  
Shielding Gas ◽  
Metal Arc Welding ◽  
Arc Welding Process

The research was study the effect of gas metal arc welding process parameters on mechanical property. The specimen was carbon steel ASTM A285 grade A which thickness of 6 mm. The experiments with full factorial design. The factors used in this study are shielding gas and voltage. The welded specimens were tested by tensile strength testing and hardness testing according to ASME boiler and pressure vessel code section IX 2007. The result showed that both of shielding gas and voltage had interaction on tensile strength and hardness at 95% confidential (P value < 0.05). Factors affecting the tensile strength are the most carbon dioxide and 27 voltage were tensile strength 213.43 MPa. And hardness maximum of 170.60 HV can be used carbon dioxide and 24 voltage. This research can be used as data in the following appropriate parameters to gas metal arc welding process.

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

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Wenhao Wu ◽  
Ming Zhao ◽  
Haiyan Wang ◽  
Yanxia Zhang ◽  
Tong Wu
Keyword(s):  
Corrosion Resistance ◽  
Weld Metal ◽  
Base Metal ◽  
Corrosion Behavior ◽  
Arc Welding ◽  
Production Efficiency ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Metal Arc Welding ◽  
X80 Steel

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.

scholarly journals Silicate Island Formation in Gas Metal Arc Welding

2021 ◽  
Vol 100 (01) ◽  
pp. 13-26
Author(s):  
RICHARD DERRIEN ◽  
◽  
ETHAN MICHAEL SULLIVAN ◽  
STEPHEN LIU ◽  
ELODIE MOINE ◽  
...  
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Formation Rate ◽  
Welding Process ◽  
Electromagnetic Levitation ◽  
Welding Parameters ◽  
Silicate Formation ◽  
Metal Arc Welding ◽  
Initial Melting

Because formation of silicate islands during gas metal arc welding is undesirable due to decreased productivity and decreased quality of welds, it is important to understand the mechanism of the formation of these silicate islands to mitigate their presence in the weld. The effects of welding parameters on the silicate formation rate were studied. Results showed that the applied voltage and oxidizing potential of the shielding gas were the parameters that most strongly influenced the amount of silicates formed on the surface of the weld bead. High-speed video was used to observe the formation of silicate islands during the welding process, which showed that the silicates were present at each stage of the welding process, including the initial melting of the wire electrode, and grew by coalescence. A flow pattern of the silicate islands was also proposed based on video analysis. An electromagnetic levitation system was used to study the growth kinetics of the silicate islands. Silicate coverage rate was found to increase with increasing oxidizing time, increasing oxidizing potential of the atmosphere, and increasing content of alloying elements except for Ti.

scholarly journals Effects of Active Gases on Droplet Transfer and Weld Morphology in Pulsed-Current NG-GMAW of Mild Steel

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Guoqiang Liu ◽  
Xinhua Tang ◽  
Qi Xu ◽  
Fenggui Lu ◽  
Haichao Cui
Keyword(s):  
Mild Steel ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Pulsed Current ◽  
Narrow Gap ◽  
Shielding Gas ◽  
Droplet Transfer ◽  
Pure Argon ◽  
Metal Arc Welding

AbstractThe current research of narrow-gap gas metal arc welding (NG-GMAW) primarily focuses on improving the sidewall fusion and avoiding the lack-of-fusion defect. However, the high cost and operation difficulty of the methods limit the industrial application. In this study, small amount of active gases CO2 and O2 were added into pure argon inert shielding gas to improve the weld formation of pulsed-current narrow-gap gas metal arc welding (NG-GMAW) of mild steel. Their effects on droplet transfer and arc behavior were investigated. A high-speed visual sensing system was utilized to observe the metal transfer process and arc morphology. When the proportion of CO2, being added into the pure argon shielding gas, changes from 5% to 25%, the metal transfer mode changes from pulsed spray streaming transfer to pulsed projected spray transfer, while it remains the pulsed spray streaming transfer when 2% to 10% O2 is added. Both CO2 and O2 are favorable to stabilizing arc and welding process. O2 is even more effective than CO2. However, O2 is more likely to cause slags on the weld surface, while CO2 can improve the weld appearance in some sense. The weld surface concavity in NG-GMAW is greatly influenced by the addition of active gas, but the weld width and weld penetration almost keep constant. This study proposes a new method which is beneficial to improving the weld bead formation and welding process stability.

Improvement of Welding Stability and Toughness Using Gas Metal Arc Welding in Pure Ar Shielding Gas

2013 ◽  
Vol 7 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Terumi Nakamura ◽  
◽  
Kazuo Hiraoka ◽  
Keyword(s):  
Weld Metal ◽  
Oxygen Concentration ◽  
Arc Welding ◽  
Gma Welding ◽  
Gas Metal Arc Welding ◽  
Shielding Gas ◽  
High Quality ◽  
Metal Arc Welding ◽  
Welding Stability

We develop a coaxial multilayer solid wire to use in Gas Metal Arc welding with pure Ar shielding gas (Ar-GMA welding). The oxygen concentration in weld metal that degrades the welded parts is reduced using by Ar-GMA welding. We produce stable welds with pure Ar shielding gas and obtain a high-quality joint with improved toughness.

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