Oxide contributions on arc plasma in tungsten inert gas welding of magnesium alloy

Abstract

To study the effects of oxide activating flux on the arc plasma, the investigation is carried out in tungsten inert gas (TIG) welding on magnesium alloy. In this study, five oxides, ZnO, MnO₂, Cr₂O₃, CeO₂ and CdO, are selected to study the roles of activating flux on the plasma characteristics (shape, electron temperature and electron density) and the arc voltage. The mechanism is also discussed by comparisons between single TIG welding processes with and without fluxes. Results reveal that the electron temperature of arc plasma decreases sharply under the influence of oxide; however, the electron density and the arc voltage get enhanced. The reasons for the increase in arc voltage are the greater electricity resistances that result from the improved welding current density and the constriction of conduction channel.

Keywords

Tungsten inert gas Activating flux Electron temperature Electron density Arc voltage

Get full access to this article

View all access options for this article.

References

Lucas

, Howse

: ‘Activating flux-increasing the performance and productivity of the TIG and plasma processes’, Weld. Met. Fabr., 1996, 64, 11–17.

Anderson

PCJ

, Wiktorowicz

: ‘Improving productivity with ATIG welding’, Weld. Met. Fabr., 1996, 64, 108–109.

Lin

, Yang

, He

, Dai

, Zhu

: ‘Effect of flux with single component on weld depth in A-TIG welding of magnesium alloy’, Trans. Nonferrous. Met. Soc. China, 2005, 15, 56–59.

Gurevich

, Zamkov

, Kushmienko

: ‘Increase in the efficiency of penetration of titanium alloys in argon-arc welding’, Avtom. Svarka., 1965, 9, 1–4.

Zamkov

, Prilutskii

, Gurevich

: ‘Effect of the composition of the flux on the welding of Ti with a permanent electrode’, Avtom. Svarka., 1977, 4, 22–26.

Sire

, Marya

: ‘New perspectives in TIG welding of aluminium through flux application FBTIG process’, Proc. 7th Int. Symp. JWS, Kobe, 2001, 113–118.

Marya

, Edwards

: ‘Chloride contributions in flux-assisted GTA welding of magnesium alloys’, Weld. J., 2002, 81, 291–298.

Simonik

: ‘Influence of halides on the penetration effect in argon-arc welding of titanium alloys’, Weld. Prod., 1974, 21, 81–82.

Sun

, Pan

: ‘Welding of titanium alloy with activating flux’, Sci. Technol. Weld. Join, 2004, 9, 337–344.

10.

Heiple

, Roper JR : ‘Mechanism for minor element effect on GTA fusion zone geometry’, Weld. J., 1982, 61, 97s–102s.

11.

Wang

, Kusumoto

, Nezu

: ‘Investigation into micro-tungsten inert gas arc behaviour and weld formation’, Sci. Technol. Weld. Join., 2004, 9, 90–94.

12.

Rodrigues

, Loureiro

, Batista

: ‘Effect of activating fluxes on bead geometry and on microstructure of A-TIG welds’, Weld. Word, 2005, 49, 415–425.

13.

Yang

, Lin

, Liu

, Wu

, Zhang

: ‘Research on the mechanism of penetration increase by flux in A-TIG welding’, J. Mater. Sci. Technol., 2003, 19, 225–227.

14.

Ludwig

: ‘Current density and anode spot size in the gas tungsten arc’, Weld. J., 1968, 47, 234–240.

15.

Paton

, Zamkov

, Prilutsky

, Poritsky

: ‘Contraction of the welding arc caused by the flux in tungsten-electrode argon-arc-welding’, Paton Weld. J., 2000, 1, 5–11.

16.

Zhang

, Zhang

: ‘Spectral analysis of welding plasma of magnesium alloy using flux coated wire’, Mater. Trans., 2009, 50, 1909–1914.

17.

Liu

, Chen

: ‘Interactions between laser and arc plasma during laser–arc hybrid welding of magnesium alloy’, Opt. Lasers Eng., 2011, 49, 1224–1231.

18.

Sabbaghzadeh

, Dadras

, Torkamany

: ‘Comparison of pulsed Nd:YAG laser welding qualitative features with plasma plume thermal characteristics’, J. Phys. D.: Appl Phys., 2007, 40, 1047–1051.

19.

Shea

, Gardner

: ‘Spectroscopic measurement of hydrogen contamination in weld arc plasmas’, J. Appl. Phys., 1983, 54, 4928–4938.

20.

Lacroix

, Jeandel

, Boudot

: ‘Spectroscopic characterization of laser-induced plasma created during welding with a pulsed Nd:YAG laser’, J. Appl. Phys., 1997, 81, 6599–6606.

21.

National Institute of Standards and Technology database, http://physics.nist.gov/PhysRefData/ASD/lines form.html

22.

Griem

: ‘Plasma spectroscopy’; 1964, New York, McGraw-Hill.

23.

Tusek

, Suban

: ‘Hybrid welding with arc and laser beam’, Sci. Technol. Weld. Join., 1999, 4, 308–311.