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Welding in the World

, Volume 61, Issue 3, pp 473–481 | Cite as

Optimising the welding conditions to determine the influence of shielding gas on fume formation rate and particle size distribution for gas metal arc welding

  • K. R. Carpenter
  • B. J. Monaghan
  • D. Cuiuri
  • J. Norrish
Research Paper

Abstract

An automatic voltage control technique, to optimise gas metal arc welding (GMAW) conditions for minimised fume generation, was compared to conventional constant-voltage operation on the influence of shielding gas on fume formation rate (FFR) and particle size distribution. Significant reductions in FFR were attributed to reductions in the arc length and current and to improved metal transfer stability, achieved by promoting the ‘drop-spray’ transfer condition and reducing repelled globular transfer. A general decrease in average particle size was observed when using the automatic control technique for the O2-bearing shielding gases, which is significant, as finer particulates are more likely to be inhaled into the lungs. The proposed mechanism to explain this behaviour was lower arc temperatures combined with an increase in the availability of oxygen, leading to nucleation of large amounts of extremely fine fume particles when the supercooling of the vapour was large. FFR increased as CO2 content increased due mainly to the dominant influence of CO2 on metal transfer and arc characteristics. It is recommended that the influence of shielding gas on FFR should be investigated using optimised welding conditions for each shielding gas composition for GMAW, especially when operating in the spray regime.

Keywords (IIW Thesaurus)

Shielding gases Fume analysis Gas-shielded arc welding Spray transfer Fume control Occupational health 

Notes

Acknowledgements

Linde-BOC Gases, Australia, are gratefully acknowledged for the funding and support for this project.

Supplementary material

40194_2017_438_MOESM1_ESM.docx (9.6 mb)
ESM 1 (DOCX 9816 kb)
40194_2017_438_MOESM2_ESM.avi (3.3 mb)
Online resource 1 Ar-5CO2-32 V video; long arc length with fluctuations in arc width. Droplets collided with one another and a few exploded due to arc interactions between colliding droplets. This appeared to generate increased fume. Larger droplets rotated within the arc. (AVI 3355 kb)
40194_2017_438_MOESM3_ESM.avi (3.5 mb)
Online resource 2 Ar-5CO2-Auto video; Shorter arc length and more stable compared to 32 V, but also had several exploding droplets that destabilised the arc (AVI 3584 kb)
40194_2017_438_MOESM4_ESM.avi (3.4 mb)
Online resource 3 Ar-10CO2-32 V video; longer arc length and fluctuation in the arc width due to periodically larger droplets. Typically streaming spray transfer, at an increased rate compared to auto-control. There were multiple droplet collisions and rotating droplets in the arc. (AVI 3442 kb)
40194_2017_438_MOESM5_ESM.avi (3.7 mb)
Online resource 4 Ar-10CO2-Auto video; Shorter arc length, mixture of drop-spray transfer and streaming spray transfer. Arc more stable than 32 V, but still had fluctuations in the arc width. There was less droplet interaction during drop-spray transfer compared to streaming spray. (AVI 3832 kb)
40194_2017_438_MOESM6_ESM.avi (3.6 mb)
Online resource 5 Ar-18CO2-32 V video; long arc length with fluctuations in width. Typically streaming spray transfer where the conglomeration of droplets was common. There were some exploding droplets due to arc interactions between droplets.) (AVI 3661 kb)
40194_2017_438_MOESM7_ESM.avi (3.8 mb)
Online resource 6 Ar-18CO2-Auto video; typically showed repelled globular transfer and had a very short arc length. (AVI 3876 kb)
40194_2017_438_MOESM8_ESM.avi (3.7 mb)
Online resource 7 Ar-18CO2-32 V-Glob video; Repelled globular transfer was observed (short arc lengths) when using Ar-18CO2 (AVI 3784 kb)
40194_2017_438_MOESM9_ESM.avi (3.4 mb)
Online resource 8 Ar-5CO2-2O2-32 V video; Very long arc length and fluctuations of arc width. Typically streaming spray transfer, where the conglomeration of droplets was common. There were several exploding droplets due to arc interactions between droplets (AVI 3524 kb)
40194_2017_438_MOESM10_ESM.avi (3.4 mb)
Online resource 9 Ar-5CO2-2O2-Auto video; Significantly shorter arc length compared to 32 V. Mixture of streaming spray and drop-spray transfer, with very few exploding droplet events (AVI 3531 kb)
40194_2017_438_MOESM11_ESM.avi (3.5 mb)
Online resource 10 Ar-5CO2-5O2-32 V video; long arc length with fluctuations in width. Typically streaming spray transfer where the conglomeration of droplets was common. Some large conglomerations were partially repelled by the arc below the droplet. There were only a few cases of exploding droplets due to arc interactions between droplets. (AVI 3617 kb)
40194_2017_438_MOESM12_ESM.avi (3.5 mb)
Online resource 11 Ar-5CO2-5O2-Auto video; Much shorter arc length and arc transfer was a mixture of streaming spray and drop-spray and the arc was much more stable compared to 32 V. (AVI 3621 kb)
40194_2017_438_MOESM13_ESM.avi (3.9 mb)
Online resource 12 Ar-12CO2-2O2-32 V video; Short arc length. Arc transfer was a mixture of streaming spray with repelled globular, where multiple droplet explosions occurred. Substantial arc interactions were visible with larger droplets, which appeared to generate increased fume. (AVI 3964 kb)
40194_2017_438_MOESM14_ESM.avi (3.4 mb)
Online resource 13 Ar-12CO2-2O2-Auto video; short arc length. Arc transfer was predominately repelled globular. Arc was relatively unstable compared to other Auto-control tests. (AVI 3489 kb)
40194_2017_438_MOESM15_ESM.avi (4.3 mb)
Online resource 14 Ar-18CO2-2O2-32 V video; Long arc length with streaming spray transfer. Substantial arc interactions were visible with larger conglomerated droplets, which appeared to generate increased fume. There were several instances of repelled globular transfer with short arc lengths and high fume generation (AVI 4431 kb)
40194_2017_438_MOESM16_ESM.avi (3.4 mb)
Online resource 15 Ar-18CO2-2O2-Auto video; Typically a shorter arc length compared to 32 V. Arc transfer was streaming spray with significant interactions with the arc, where multiple droplets exploded, generating increased fume (similar to repelled globular transfer). The arc was relatively unstable. (AVI 3517 kb)
40194_2017_438_MOESM17_ESM.avi (3.7 mb)
Online resource 16 Ar-20He-12CO2-32 V video; Mixture of spray transfer and repelled globular, where a long detachment event was observed at the end of the video. The brightness of the arc beneath the forming droplet, indicating a very hot arc, would generate increased fume. Larger droplets tend to rotate and cause arc instability. (AVI 3798 kb)
40194_2017_438_MOESM18_ESM.avi (4 mb)
Online resource 17 Ar-20He-12CO2-Auto video; Mixture of spray and repelled globular transfer, but with a much shorter arc length compared to 32 V. Larger droplets tend to rotate and cause arc instability. (AVI 4116 kb)
40194_2017_438_MOESM19_ESM.avi (3.8 mb)
Online resource 18 Ar-30He-6CO2-32 V video; Streaming spray transfer and a long arc length. Conglomeration of droplets was frequent and larger droplets tended to rotate (AVI 3924 kb)
40194_2017_438_MOESM20_ESM.avi (4.3 mb)
Online resource 19 Ar-30He-6CO2-Auto video; Predominately repelled globular transfer with some arc instabilities. Very short arc length. There was a period of drop-spray transfer towards the end of the video. (AVI 4393 kb)
40194_2017_438_MOESM21_ESM.avi (3.9 mb)
Online resource 20 Ar-30He-10CO2-32 V video; Moderate arc length. Mixture of spray transfer and repelled globular. Arc instabilities occurred during large droplet formation and detachment, which would be expected to increase fume generation. (AVI 3950 kb)
40194_2017_438_MOESM22_ESM.avi (3.5 mb)
Online resource 21 Ar-30He-10CO2-Auto video; Moderate arc length, similar to 32 V. Predominately streaming stray transfer, where there was significant narrowing of the end of the electrode. Arc interactions between streaming droplets is clearly visible. Arc more stable compared to the 32 V tests. (AVI 3555 kb)

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Copyright information

© International Institute of Welding 2017

Authors and Affiliations

  • K. R. Carpenter
    • 1
  • B. J. Monaghan
    • 2
  • D. Cuiuri
    • 1
  • J. Norrish
    • 1
    • 3
  1. 1.Welding Engineering Research Group, School of Mechanical, Materials and Mechatronics EngineeringUniversity of WollongongWollongongAustralia
  2. 2.School of Mechanical, Materials and Mechatronics Engineering, Faculty of Engineering and Information SciencesUniversity of WollongongWollongongAustralia
  3. 3.Defence Materials Technology Centre Ltd., Faculty of Engineering and Information SciencesUniversity of WollongongWollongongAustralia

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