Abstract
This study performed root pass welding with a V-groove using a pulsed gas metal arc welding process for mild steel. Welding process parameters such as weaving, root gap size, and travel speed were major factors in the formation of the back-bead. A high-speed camera and a synchronized data acquisition system captured dynamic molten pool images and welding signals (current and voltage) simultaneously. The back-bead shape differed depending on the root gap opening. Without a root gap, the accumulated molten pool created a cushion effect in the arc center which reduced the momentum of downward flow. In contrast, the back-bead depth could be formed with a root gap opening (1 mm, 2 mm), but the back-bead shapes were different from each other at different travel speeds. The back-bead shapes also varied depending on the weaving conditions. Despite the same amount of heat input, the microstructures also varied depending on the weaving. The microstructures in the heat-affected zone with weaving were mixed with ferrite and pearlite. However, the microstructures in the heat-affected zone without weaving mainly consisted of coarse bainite. Acicular ferrite with some amount of grain boundary ferrite dominated in the weld metal in all cases.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Kumar R, Dilthey U, Dwivedi DK, Ghosh PK (2009) Thin sheet welding of Al 6082 alloy by AC pulse-GMA and AC wave pulse-GMA welding. Mater Des 30(2):306–313
Kim RH, Choi GD, Kim CH, Cho DW, Na SJ (2012) Arc characteristics in pulse-GMA welding with acute groove angles. Weld J 91(4):101–105
Zhang YM, Liguo E, Kovacevic R (1998) Active metal transfer control by monitoring excited droplet oscillation. Weld J 77(9):388–395
Wu CS, Chen MA, Li SK (2004) Analysis of excited droplet oscillation and detachment in active control of metal transfer. Comput Mater Sci 31:147–154
Nagarajan S, Banerjee P, Chen W, Chin BA (1992) Control of the welding process using infrared sensors. IEEE Trans Robot Autom 8(1):86–93
Zhang WJ, Liu YK, Wang X, Zhang YM (2012) Characterization of three dimensional weld pool surface in GTAW. Weld J 91(7):195–203
Liu YK, Zhang WJ, Zhang YM (2013) Dynamic neuro-fuzzy-based human intelligence modeling and control in GTAW. IEEE Trans Autom Sci Eng 12(1):324–335
Wu D, Chen H, Huang Y, He Y, Hu M, Chen S (2017) Monitoring of weld joint penetration during variable polarity plasma arc welding based on the keyhole characteristics and PSO-ANFIS. J Mater Process Technol 239:113–124
Yamane S, Yamamoto H, Ishihara T, Kubota T, Eguchi K, Oshima K (2004) Adaptive control of back bead in V groove welding without backing plate. Sci Technol Weld Join 9(2):138–148
Ueyama T, Ohnawa T, Tanaka M, Nakata K (2005) Effects of torch configuration and welding current on weld bead formation in high speed tandem pulsed gas metal arc welding of steel sheets. Sci Technol Weld. Joi 10(6):750–759
Yamane S, Uji K, Nakajima T, Yamamoto H (2015) Application of switch back welding to V groove MAG welding. Weld Int 29(2):103–109
Cho DW, Na SJ, Cho MH, Lee JS (2013) A study on V-groove GMAW for various welding positions. J Mater Process Technol 213(9):1640–1652
Zhou YB, Fang DS, Liu LM (2017) Root welding of V-groove thick plate without backing plate by MAG-TIG double-arc welding. J Precis Eng Manuf 18(4):623–628
Frostevarg J (2018) Factors affecting weld root morphology in laser keyhole welding. Opt Lasers Eng 101:89–98
Bachmann M, Avilov V, Gumenyuk A, Rethmeier M (2011) Numerical simulation of full-penetration laser beam welding of thick aluminium plates with inductive support. J Phys D Appl Phys 45:035201
Cho DW, Park JH, Moon HS (2019) A study on molten pool behavior in the one pulse one drop GMAW process using computational fluid dynamics. Int J Heat Mass Transf 139:848–859
Park JH, Kim SH, Moon HS, Kim MH (2019) Influence of gravity on molten pool behavior and analysis of microstructure on various welding positions in pulsed gas metal arc welding. Appl Sci 9(21):4626
Cho DW, Lee SH, Na SJ (2013) Characterization of welding arc and weld pool formation in vacuum gas hollow tungsten arc welding. J Mater Process Technol 213(2):143–152
Cho JH, Na SJ (2009) Three-dimensional analysis of molten pool in GMA-laser hybrid welding. Weld J 88(2):35–43
Cho WI, Na SJ, Cho MH, Lee JS (2010) Numerical study of alloying element distribution in CO2 laser-GMA hybrid welding. Comput Mater Sci 49(4):792–800
Cao ZN, Dong P (1998) Modeling of GMA weld pools with consideration of droplet impact. J Eng Mater Technol 120(4):313–320
Frostevarg J, Haeussermann T. (2015) Dropout formation in thick steel plates during laser welding. The IIW international conference on high strength materials–challenges and applications, Helsinki, Finland. 2-3 July 2015
Qi Y, Genyu C, Shilei D, Dianwu Z (2019) Periodic root humps in thick-plate laser welding using steady electromagnetic force. J Mater Process Technol 273:116247
Cho DW, Na SJ (2015) Molten pool behaviors for second pass V-groove GMAW. Int J Heat Mass Transf 88:945–956
Funding
This work was supported by the Korea Institute of Machinery and Materials (NK226C) and National Research Foundation of Korea (NRF-2019M2C9A1057806).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that there are no conflicts of interest.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Park, JH., Kim, SH., Moon, HS. et al. Effect of process parameters on root pass welding and analysis of microstructure in V-groove pulsed gas metal arc welding for mild steel. Int J Adv Manuf Technol 109, 1969–1985 (2020). https://doi.org/10.1007/s00170-020-05736-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00170-020-05736-6