scholarly journals INFORMATION-MEASURING COMPLEX FOR INVESTIGATION OF MELTING AND ELECTRODE METAL TRANSFER AT ARC WELDING

2020 ◽  
Vol 2020 (6) ◽  
pp. 4-11
Author(s):  
Sergey Bolotov ◽  
Aleksandr Homchenko ◽  
Aleksandr Shul'ga ◽  
Evgeniya Bolotova
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Video Camera ◽  
Metal Transfer ◽  
Infrared Range ◽  
Cold Metal Transfer ◽  
Optimum Frequency ◽  
Power Characteristics ◽  
Cold Metal ◽  
Electrode Metal

The purpose of the paper consists in the description of the procedure for investigations and software-hardware means for arc welding with a melting electrode in protective gas environment with the controlled transfer of electrode metal and its visualization. For investigations of quick electrode metal transfer processes there was used Evercam 1000-4-C digital video-camera and RKDP-0401recorder of welding mode parameters. For video-control of the process there was used a method of active illumination with the further image filtration. It is determined that the visualization of a welding drop transfer dynamics during arc welding with melting electrode in protective gases should be carried out in the infrared range on one side limited with the curve of a spectral transmission of light filters – 950 nm, and on the other side of a matrix sensitivity spectral curve of a rapid camera -1050 nm. There is developed software in the environment of the LabVIEW graphical programming allowing the fulfillment of adjustment and programming welding mode parameters and high-speed shooting, device synchronization, superposition on oscillograms of electric parameters of the electrode metal image transfer, definition of power characteristics at different interval of drop transfer. The CMT (Cold Metal Transfer) process with the aid of the equipment of Fronius TransPuls Synergic 3200 is investigated. It is defined that for arc welding in protective gases an optimum frequency of video-shooting is 1500-2000 shots per second at resolution from 640x608 pixels to 320x400 pixels that allows analyzing efficiently rapid processes of drop transfer.

A52M/SA52 Dissimilar Metal RPV Repair Weld: Experimental Evaluation and Post-Weld Characterizations

2020 ◽  
Author(s):  
Iikka Virkkunen ◽  
Mikko Peltonen ◽  
Henrik Sirén ◽  
Pekka Nevasmaa ◽  
Caitlin Huotilainen ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Arc Welding ◽  
Nuclear Power ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Reactor Pressure Vessel ◽  
Cold Metal Transfer ◽  
Metal Arc Welding ◽  
Cold Metal ◽  
Reactor Pressure

Abstract Aging management of the existing fleet of nuclear power plants is becoming an increasingly important topic, especially as many units are approaching their design lifetimes or are entering long-term operation. As these plants continue to age, there is an increased probability for the need of repairs due to extended exposure to a harsh environment. It is paramount that qualified and validated solutions are readily available. A repair method for a postulated through cladding crack into the low alloy steel of a nuclear power plant’s reactor pressure vessel has been investigated in this study. This paper is part of larger study that evaluates the current possibilities of such repair welds. The present paper documents the weld-trials and method selection. A parallel paper describes numerical simulations and optimization of weld parameters. The presented weld-trial represents a case where a postulated crack has been excavated and repaired using a nickel base Alloy 52M filler metal by gas metal arc welding-cold metal transfer with a robotic arm. A SA235 structural steel has been used as a base material in this weld-trial. No pre-heating or post-weld heat treatment will be applied, as it would be nearly impossible to apply these treatments in a reactor pressure vessel repair situation. While Alloy 52M presents good material properties, in terms of resistance to environmentally assisted degradation mechanisms, such as primary water stress corrosion cracking, it is notoriously difficult to weld. Some difficulties and challenges during welding include a sluggish weld puddle, formation of titanium and/or aluminium oxides and its susceptibility to lack of fusion defects and weld metal cracking, such as ductility dip cracking and solidification cracking. Moreover, gas metal arc welding-cold metal transfer is not traditionally used in the nuclear industry. Nonetheless, it presents some interesting advantages, specifically concerning heat input requirements and automation possibilities, as compared to traditional welding methods. The mechanical properties, in terms of indentation hardness, and microstructure of a weld-trial sample have been evaluated in this study. The fusion boundary and heat affected zone were the main areas of focus when evaluating the mechanical and microstructural properties. Detailed microstructural characterization using electron backscatter diffraction and nanoindentation were performed across the weld interface. Based on these results, the gas metal arc welding cold metal transfer is seen as a potential high-quality weld method for reactor pressure vessel repair cases.

Erratum to: Mechanisms of weld pool flow and slag formation location in cold metal transfer (CMT) gas metal arc welding (GMAW)

2017 ◽  
Vol 61 (6) ◽  
pp. 1287-1287 ◽  
Author(s):  
Md. R. U. Ahsan ◽  
Muralimohan Cheepu ◽  
Rouholah Ashiri ◽  
Tae-Hoon Kim ◽  
Chanyoung Jeong ◽  
...  
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Slag Formation ◽  
Cold Metal Transfer ◽  
Metal Arc Welding ◽  
Cold Metal

Cold-Metal-Transfer Arc Joining of Al 6K32 Alloy to Steel Sheets

2013 ◽  
Vol 334-335 ◽  
pp. 247-251 ◽  
Author(s):  
Min Jung Kang ◽  
Cheol Hee Kim
Keyword(s):  
Automotive Industry ◽  
Arc Welding ◽  
Intermetallic Phase ◽  
Metal Transfer ◽  
Cold Metal Transfer ◽  
Steel Sheets ◽  
Welding Technology ◽  
Coating Type ◽  
Cold Metal ◽  
Interface Layers

In the arc joining of dissimilar metals, such as steel and Al alloys, a brittle intermetallic phase is formed at the interface. The thickness of this phase should be minimized because it causes solidification cracking. Cold metal transfer (CMT) arc welding technology is widely used throughout the automotive industry because of low spatter formation and heat input. A CMT arc was used to investigate arc joining between the Al 6K32 alloy and mild steel sheets. The behaviors of the interface layers were analyzed on the basis of filler wires and the coating type of the steel sheets. The thickness of the intermetallic phase was maintained under 10 μm and increased joint strength was achieved by selecting the appropriate filler wire and coating type.

scholarly journals Gas Metal Arc Welding Modes in Wire Arc Additive Manufacturing of Ti-6Al-4V

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2457
Author(s):  
Oleg Panchenko ◽  
Dmitry Kurushkin ◽  
Fedor Isupov ◽  
Anton Naumov ◽  
Ivan Kladov ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Process Data ◽  
Cold Metal Transfer ◽  
Wall Width ◽  
Metal Arc Welding ◽  
Wire Arc Additive Manufacturing

In wire arc additive manufacturing of Ti-alloy parts (Ti-WAAM) gas metal arc welding (GMAW) can be applied for complex parts printing. However, due to the specific properties of Ti, GMAW of Ti-alloys is complicated. In this work, three different types of metal transfer modes during Ti-WAAM were investigated: Cold Metal Transfer, controlled short circuiting metal transfer, and self-regulated metal transfer at a direct current with a negative electrode. Metal transfer modes were studied using captured waveform and high-speed video analysis. Using these modes, three walls were manufactured; the geometry preservation stability was estimated and compared using effective wall width calculation, the microstructure was analyzed using optical microscopy. Transfer process data showed that arc wandering depends not only on cathode spot instabilities, but also on anode processing properties. Microstructure analysis showed that each produced wall consists of phases and structures inherent for Ti-WAAM. α-basketweave in the center of and α-colony on the grain boundary of epitaxially grown β-grains were found with heat affected zone bands along the height of the walls, so that the microstructure did not depend on metal transfer dramatically. However, the geometry preservation stability was higher in the wall, produced with controlled short circuiting metal transfer.

Development of Pulsed Cold Metal Transfer and Gas Metal Arc Welding Techniques on High-Strength Aerospace-Grade AA7475-T761

2020 ◽  
Vol 29 (11) ◽  
pp. 7270-7290
Author(s):  
T. A. Vigneshwara Kumaran ◽  
S. A. Nithin Joseph Reddy ◽  
S. Jerome ◽  
N. Anbarasan ◽  
N. Arivazhagan ◽  
...  
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
Metal Transfer ◽  
Cold Metal Transfer ◽  
Metal Arc Welding ◽  
Cold Metal

Mechanisms of weld pool flow and slag formation location in cold metal transfer (CMT) gas metal arc welding (GMAW)

2017 ◽  
Vol 61 (6) ◽  
pp. 1275-1285 ◽  
Author(s):  
Md. R . U. Ahsan ◽  
Muralimohan Cheepu ◽  
Rouholah Ashiri ◽  
Tae-Hoon Kim ◽  
Chanyoung Jeong ◽  
...  
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Slag Formation ◽  
Cold Metal Transfer ◽  
Metal Arc Welding ◽  
Cold Metal
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