Effects of active gases on droplet transfer and weld morphology in pulsed-current NG-GMAW of mild steel
The 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.
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Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the latest manuscript can be downloaded and accessed as a PDF.
Posted 15 Jan, 2021
On 07 Jan, 2021
On 07 Jan, 2021
On 07 Jan, 2021
On 28 Dec, 2020
Received 27 Jun, 2020
On 09 Jun, 2020
Received 06 Jun, 2020
On 18 May, 2020
Invitations sent on 11 May, 2020
On 06 May, 2020
On 05 May, 2020
On 05 May, 2020
On 05 May, 2020
Effects of active gases on droplet transfer and weld morphology in pulsed-current NG-GMAW of mild steel
Posted 15 Jan, 2021
On 07 Jan, 2021
On 07 Jan, 2021
On 07 Jan, 2021
On 28 Dec, 2020
Received 27 Jun, 2020
On 09 Jun, 2020
Received 06 Jun, 2020
On 18 May, 2020
Invitations sent on 11 May, 2020
On 06 May, 2020
On 05 May, 2020
On 05 May, 2020
On 05 May, 2020
The 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.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the latest manuscript can be downloaded and accessed as a PDF.