Welding in the World

, Volume 61, Issue 6, pp 1275–1285 | Cite as

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

  • Md. R . U. Ahsan
  • Muralimohan Cheepu
  • Rouholah Ashiri
  • Tae-Hoon Kim
  • Chanyoung Jeong
  • Yeong -Do Park
Research Paper


This work investigates the weld pool flow behavior by observing the flow pattern of floating slag particles for cold metal transfer (CMT) gas metal arc welding (GMAW) using three different welding wires. These wires contain different amount of deoxidizers in the form of silicon and manganese. In situ high-speed videography shows that for the wire containing a high amount of deoxidizer, the weld pool flows from the center towards the toe. With the presence of a lower amount of deoxidizers, it flows from the toe towards the center. Besides, a higher amount of CO2 in the shielding gas changes the amount and location of slag formation. Chemical composition analysis of weld metals relates the weld pool flow behavior with the amount of dissolved oxygen (surface active element). The presence of adequate amount of oxygen in the weld pool can alter the weld pool flow pattern, which changes with the amount of deoxidizers present in the materials and the amount of oxygen supplied through the shielding gas. Based on this concept, the mechanisms involved in weld pool flow pattern and slag formation location for different composition of the consumables are disclosed to improve weld quality and productivity through the selection of the proper welding consumables in CMT-GMAW.

Keywords (IIW Thesaurus)

Marangoni convection Surface active elements Flow visualization Slag Cold metal transfer (CMT) Gas metal arc welding (GMAW) 


  1. 1.
    Wang Y, Tsai HL (2001) Effects of surface active elements on weld pool fluid flow and weld penetration in gas metal arc welding. Metall Mater Trans B Process Metall Mater Process Sci 32:501–515. doi: 10.1007/s11663-001-0035-5 CrossRefGoogle Scholar
  2. 2.
    Mcnallan MJ, Debroy T (1991) Effect of temperature and in Fe-Ni-Cr alloys containing sulfur. Metall Trans B 22:557–560CrossRefGoogle Scholar
  3. 3.
    Sahoo P, Debroy T, McNallan MJ (1988) Surface tension of binary metal-surface active solute systems under conditions relevant to welding metallurgy. Metall Trans B 19:483–491. doi: 10.1007/BF02657748 CrossRefGoogle Scholar
  4. 4.
    Kou S, Limmaneevichitr C, Wei PS (2011) Oscillatory Marangoni flow: a fundamental study by conduction-mode laser spot welding. Weld J 90:229s–240sGoogle Scholar
  5. 5.
    Hasegawa M, Watabe M, Young WH (2000) Theory of the surface tension of liquid metals. J Phys F Met Phys 11:173–177. doi: 10.1088/0305-4608/11/8/001 CrossRefGoogle Scholar
  6. 6.
    Chacon E, Flores F, Navascues G (2000) A theory for liquid metal surface tension. J Phys F Met Phys 14:1587–1601. doi: 10.1088/0305-4608/14/7/009 CrossRefGoogle Scholar
  7. 7.
    Heiple CR, Roper JR (1982) Mechanism for minor element effect on {GTA} fusion zone geometry. Weld J 61:97s–102sGoogle Scholar
  8. 8.
    Heiple CR, Roper JR (1981) Effect of selenium on GTAW fusion zone geometry. Weld J 143–145Google Scholar
  9. 9.
    Heiple CR, Roper JR, Stagner RT, Aden RJ (1983) Surface active element effects on the shape of GTA, laser and electron beam welds. Weld J 72–77Google Scholar
  10. 10.
    Burgardt P (1985) Effects of SO2 shielding gas additions on GTA Weld Shape. 2–5Google Scholar
  11. 11.
    Limmaneevichitr C, Kou S (2000) Visualization of Marangoni convection in simulated weld pools containing a surface-active agent. Weld J 79:324s–330sGoogle Scholar
  12. 12.
    Limmaneevichitr C, Kou S (2000) Experiments to simulate effect of Marangoni convection on weld pool shape. Weld J 79:231s–237sGoogle Scholar
  13. 13.
    Ribic B, Tsukamoto S, Rai R, DebRoy T (2011) Role of surface-active elements during keyhole-mode laser welding. J Phys D Appl Phys 44:485203. doi: 10.1088/0022-3727/44/48/485203 CrossRefGoogle Scholar
  14. 14.
    Wang Y, Tsai HL (2001) Impingement of filler droplets and weld pool dynamics during gas metal arc welding process. Int J Heat Mass Transf 44:2067–2080. doi: 10.1016/S0017-9310(00)00252-0 CrossRefGoogle Scholar
  15. 15.
    Umehara Y, Suzuki R, Nakano T (2009) Development of the innovative GMA wire improving the flow direction of molten pool. Q J Jpn Weld Soc 27(2):163–168CrossRefGoogle Scholar
  16. 16.
    Ahsan RU, Kim YR, Kim CH, et al (2015) Porosity formation mechanisms in cold metal transfer (CMT) gas metal arc welding (GMAW) of zinc coated steels. 1–7. doi: 10.1179/1362171815Y.0000000084
  17. 17.
    Ahsan RU, Kim YR, Ashiri R et al (2016) Cold metal transfer (CMT) GMAW of zinc-coated steel. Weld J 95:120–132Google Scholar
  18. 18.
    Pickin CG, Williams SW, Lunt M (2011) Characterisation of the cold metal transfer (CMT) process and its application for low dilution cladding. J Mater Process Technol 211:496–502. doi: 10.1016/j.jmatprotec.2010.11.005 CrossRefGoogle Scholar
  19. 19.
    Zhang HT, Feng JC, He P et al (2009) The arc characteristics and metal transfer behaviour of cold metal transfer and its use in joining aluminium to zinc-coated steel. Mater Sci Eng a 499:111–113. doi: 10.1016/j.msea.2007.11.124 CrossRefGoogle Scholar
  20. 20.
    AWS A5.18–93: specification for carbon steel electrodes and rods for gas shielded arc weldingGoogle Scholar
  21. 21.
    Liu S (2013) Pyrometallurgical studies of molten metal droplets for the characterization of gas metal arc welding. Trends Weld Res Proc 9th Int Conf 353–361Google Scholar
  22. 22.
    Grong O (1997) Metallurgical modelling of welding. Inst. Mater. 1 Carlt. House Terrace, London, SW 1 Y 5 DB, UK, 1997. 605Google Scholar
  23. 23.
    Mendez PF, Eagar TW (2003) Penetration and defect formation in high-current arc welding. Weld J 82:296–306Google Scholar
  24. 24.
    Debroy T, David SA (1995) Physical processes in fusion welding. Rev Mod Phys 67:85–112. doi: 10.1103/RevModPhys.67.85 CrossRefGoogle Scholar
  25. 25.
    Burgardt P, Heiple C (1986) Interaction between impurities and welding variables in determining GTA weld shape. Weld J:150–155Google Scholar
  26. 26.
    Oreper GM, Eagar TW, Szekely J (1983) Convection in arc weld pools. Weld J:307–312Google Scholar
  27. 27.
    Kuwana T, Sato Y (2009) Oxygen absorption by Fe-Mn and Fe-Si-Mn weld metal—effect of additional elements on oxygen absorption by steel weld metal during arc welding (part II). Q J Jpn Weld Soc 27:49–56Google Scholar
  28. 28.
    Lu S, Fujii H, Nogi K (2008) Marangoni convection and weld shape variations in He-CO2 shielded gas tungsten arc welding on SUS304 stainless steel. J Mater Sci 43:4583–4591. doi: 10.1007/s10853-008-2681-3 CrossRefGoogle Scholar
  29. 29.
    Kuwana T, Sato Y (2009) Oxygen absorption by Fe-Mn and Fe-Si-Mn weld metal—effect of additional elements on oxygen absorption by steel weld metal during arc welding (part II). Q J Jpn Weld Soc 27:43–49Google Scholar
  30. 30.
    Sato Y, Kuwana T, Tomita K (1993) Oxygen absorption of steel weld metal during gas metal arc welding. Weld Int 7:280–285. doi: 10.1080/09507119309548390 CrossRefGoogle Scholar
  31. 31.
    Kuwana T, Sato Y, Kaneda S (1993) Oxygen absorption and oxide inclusions in Fe-Cr weld metal. Weld Int 7:365–370. doi: 10.1080/09507119109446702 CrossRefGoogle Scholar

Copyright information

© International Institute of Welding 2017
corrected publication August 2017

Authors and Affiliations

  • Md. R . U. Ahsan
    • 1
    • 2
  • Muralimohan Cheepu
    • 3
  • Rouholah Ashiri
    • 2
    • 4
  • Tae-Hoon Kim
    • 5
  • Chanyoung Jeong
    • 2
  • Yeong -Do Park
    • 2
    • 3
  1. 1.Department of Mechanical EngineeringInternational University of Business, Agriculture and TechnologyDhakaBangladesh
  2. 2.Department of Advanced Materials EngineeringDong-Eui UniversityBusanRepublic of Korea
  3. 3.Department of Advanced Materials and Industrial Management EngineeringDong-Eui UniversityBusanRepublic of Korea
  4. 4.Department of Materials EngineeringIsfahan University of TechnologyIsfahanIran
  5. 5.R&D Center, Kiswel Co. LtdChangwonRepublic of Korea

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