Visual Investigation on the Arc Burning Behaviors and Features in Underwater Wet FCAW

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Qingyuan Yang ◽  
Yanfei Han ◽  
Chuanbao Jia ◽  
Shengfa Dong ◽  
Chuansong Wu
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Gas Flow ◽  
Water Pressure ◽  
Water Environment ◽  
Arc Length ◽  
Flux Cored Arc Welding ◽  
Gas Ionization ◽  
Joint Quality ◽  
Contact Arc

Abstract The dynamic arc behaviors have a significant effect on the process stability and welded joint quality in underwater wet flux-cored arc welding (FCAW). In this study, clear underwater arc images are obtained by using a high-speed camera, which further reveal the complex physical process of underwater wet welding. The mechanism of underwater contact arc ignition is described in detail. Gas ionization and electron emission processes are carried out in bubbles generated by resistance heat. The dynamic arc behaviors are obviously different between bubble growth and separation stages. The high-speed gas flow in the bubble separation stage has a great disturbance to the arc. The arc shapes under water and in air under the same parameters are compared, and the mechanism of arc column shrinkage and arc length shortening is revealed from the aspects of water environment cooling, gas composition in bubbles, disturbance of gas flow, water pressure, and electric field strength.

Effect of Arc Length on Weld Appearance and Metal Transfer in Twin-Wire GMAW Process

2012 ◽  
Vol 472-475 ◽  
pp. 1279-1282 ◽  
Author(s):  
Huan Ming Chen ◽  
Shao Jie Wu
Keyword(s):  
Transfer Process ◽  
Arc Welding ◽  
High Speed ◽  
Metal Transfer ◽  
High Speed Camera ◽  
Arc Length ◽  
Process Stability ◽  
Spray Transfer ◽  
Weld Appearance ◽  
Globular Transfer

The experiments were performed with the twin-wire GMAW machine of Fronius product. The metal transfer process and the arc shapes were observed by use of shadowgraph technique with a high-speed camera. When the arc length increases during twin-wire CO2 arc welding, the mode of metal transfer changes from short-circuiting transfer to globular transfer, and to spray transfer. But it is difficult to form a stable spray transfer process, and the weld appearance becomes worse. The short-circuiting transfer in twin-wire CO2 arc welding can improve the process stability.

Arc Behavior of Dry Hyperbaric Gas Metal Arc Welding

2014 ◽  
Vol 988 ◽  
pp. 245-248 ◽  
Author(s):  
Kai Li ◽  
Hong Ming Gao ◽  
Hai Chao Li
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Ambient Pressure ◽  
Gas Metal Arc Welding ◽  
Electric Signal ◽  
Signal Acquisition ◽  
Arc Length ◽  
Camera System ◽  
Arc Behavior ◽  
Metal Arc Welding

The arc behavior in dry hyperbaric Gas Metal Arc Welding (GMAW) process was investigated by using a high speed camera system and welding electric signal acquisition system. The arc shape in hyperbaric argon environment of 0.1-2MPa shows quite different characteristic from that at normal pressure. With the increase of ambient pressure, the arc length turns shorter, arc column is contracted, and the arc brightness increases. At elevated ambient pressure, the arc length increases with increasing welding voltage. Arc voltage has a good linear relation with arc length. The sum of the fall voltages at ambient pressure of 0.4MPa, 0.8MPa, and 2MPa is nearly constant which is about 20.2-21.7V. The values of electric field strength of arc column at different ambient pressure were gained through the linear fit, which are increased with increasing ambient pressure. The arc static characteristics at elevated ambient pressure are raising characteristics, and it is shifted upward with increasing ambient pressure.

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.

Limitations of the Schlieren technique for shielding gas flow visualization in arc welding processes

2021 ◽  
Author(s):  
Mateus Barancelli Schwedersky ◽  
Álisson Fernandes da Rosa ◽  
Marcelo Pompermaier Okuyama ◽  
Régis Henrique Gonçalves e Silva
Keyword(s):  
Flow Visualization ◽  
Arc Welding ◽  
Gas Flow ◽  
Shielding Gas ◽  
Schlieren Technique ◽  
Welding Processes
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