Analysis of Arc Characteristics in Oxide Active TIG Welding Based on Spectroscopy Diagnosis

doi:10.12141/j.issn.1000-565X.210699

Abstract

Abstract:

As a new welding method, active tungsten argon arc welding (A-TIG welding), which increases weld pe-netration and improves welding efficiency by coating active agent on the surface of base metal, has been widely used in actual production. As one of the most common active flux formulations in A-TIG welding, oxide’s influence mechanism for arc behavior is still in debate. In order to clarify the influence mechanism of oxide on the arc beha-vior of TIG welding, a synchronous acquisition system of arc morphology and arc spatial spectrum was established. The spectral line distribution and arc morphology characteristics of active agent particles, argon, iron and other charged particles in the arc spatial space under the action of oxide were studied, and the arc electron temperature in different regions was calculated based on Boltzmann mapping method. It is found that the relative intensity of Ar Ⅱspectral lines in the arc space decreases gradually with the increase of the distance from the cathode region. This is because the closer the arc is to the cathode region, the more concentrated the arc energy density is, the more favo-rable it is to promote the ionization of Ar atoms. SiO₂ and B₂O₃ can promote the ionization of Ar particles, while TiO₂ can inhibit the ionization of Ar particles. The distribution law of the relative intensity of Fe Ⅱ spectral lines in the axial direction is opposite to that of Ar Ⅱ spectral lines. The relative intensity of the spectral lines gradually decreases from the vicinity of the anode region to the vicinity of the cathode region. This is because the closer it is to the surface of the molten pool (near the anode region), the higher the concentration of iron vapor evaporated into the arc space is and the more obvious the ionization is. The introduction of three kinds of oxide active agents can reduce the relative intensity of Fe Ⅱ spectral lines. In the arc space coated with TiO₂ active agent, no obvious Ti Ⅰcharacteristic line and arc contraction phenomenon were detected, and the arc temperature field did not change significantly, which means that the influence of TiO₂ active agent on the arc behavior is very weak. The characteristic spectral lines of Si Ⅰ and B Ⅰ were detected in the arc space coated with SiO₂ and B₂O₃ active agents, and the two active agents can cause arc contraction, but the arc contraction has no obvious effect on the arc temperature field.

Key words: active tungsten inert gas welding, oxide, spectroscopy diagnosis, arc temperature

CLC Number:

TG403

LI Chunkai, DING Bin, SHI Yu, et al. Analysis of Arc Characteristics in Oxide Active TIG Welding Based on Spectroscopy Diagnosis[J]. Journal of South China University of Technology(Natural Science Edition), 2022, 50(8): 128-135.

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References 16

1	XU J， WANG S， CHAI Z，et al ．Comparison of the stress corrosion cracking behaviour of AISI 304 pipes welded by TIG and LBW［J］．Acta Metallurgica Sinica （English Letters），2021，34（4）：579-589．
2	GUREVICH S M， ZAMKOV V N， KUSHNIRENKO N A ．Improving the penetration of titanium alloys when they are welded by tungsten arc process［J］．Automatic Welding，1965，18（9）：1-4．
3	AHMADI E， EBRAHIMI A， HOSEINZADEH A ．Microstructure evolution and mechanical properties of 2219 aluminum alloy A-TIG welds［J］．The Physics of Metals and Metallography，2020，121（5）：483-488．
4	KULKARNI A， DWIVEDI D， VASUDEVAN M ．Study of mechanism，microstructure and mechanical properties of activated flux TIG welded P91 steel-P22 steel dissimilar metal joint［J］．Materials Science & Engineering A，2018，731：309-323．
5	BABBAR A， KUMAR A， JAIN V，et al ．Enhancement of activated tungsten inert gas （A-TIG） welding using multi-component TiO₂-SiO₂-A_l2O₃ hybrid flux［J］．Measurement，2019，148：106912．
6	LU S P， FUJII H， SUGIYAMA H，et al ．Weld pe-netration and Marangoni convection with oxide fluxes in GTA welding［J］．Materials Transactions Jim，2002，43（11）：2926-2931．
7	LI C K， SHI Y， GU Y F，et al ．Effect of oxide on surface tension of molten metal［J］．RSC Advances，2017，7：53941-53950．
8	赵玉珍，雷永平，史耀武．A-TIG焊中氧含量对熔池流动方式影响的数值模拟［J］．金属学报，2004，40（10）：1085-1092．
	ZHAO Yuzhen， LEI Yongping， SHI Yaowu ．Numerical simulation of effect of oxygen content on molten pool flow pattern in A-TIG welding［J］．Acta Metallurgica Sinica，2004，40（10）：1085-1092．
9	LECONTE S， PAILLARD P， CHAPELLE P，et al ．Effect of oxide fluxes on activation mechanisms of tun-gsten inert gas process［J］．Science and Technology of Welding and Joining，2006，11（4）：389-397．
10	MA S， GAO H， WU L ．Modified Fowler-Milne method for the spectroscopic determination of thermal plasma temperature without the measurement of continuum radiation［J］．Review of Scientific Instruments，2011，82（1）：013104．
11	RIZZI D， SIBILLANO T， CALABRESE P，et al ．Spectroscopic，energetic and metallographic investigations of the laser lap welding of AISI 304 using the response surface methodology［J］．Optics and Lasers in Engineering，2011，49（7）：892-898．
12	叶大伦，胡建华．实用无机物热力学数据手册［M］．北京：冶金工业出版社，2002．
13	陈炜煊．磁场及金属蒸气对电弧特性的影响［D］．兰州：兰州理工大学，2020．
14	TANAKA M， SHIMIZU T， TERASAKI T，et al ．Effects of activating flux on arc phenomena in gas tungsten arc welding［J］．Science and Technology of Welding and Joining，2000，5（6）：397-402．
15	SIMONIK A， PETVIASHVILI V， IVANOV A ．The effect of contraction of the arc discharge upon the introduction of electro-negative elements［J］．Svar Proiz，1976，3：49-51．
16	TSENG K H， CHEN K L ．Comparisons between TiO₂- and SiO₂-flux assisted TIG welding processes［J］．Journal of Nanoscience and Nanotechnology，2012，12（8）：6359-6367．

成分	含量/%	成分	含量/%
C	0.040 0	S	0.001 6
Mn	1.780 0	Si	0.480 0
Cr	18.050 0	Cu	0.057 9
Ni	8.050 0	N	0.053 1
P	0.035 0	Fe	余量

活性剂	相对分子质量	熔点/K	沸点/K
SiO₂	60.60	1 996	2 530
B₂O₃	69.62	723	2 133
TiO₂	79.90	2 098	3 073

参数	取值	参数	取值
焊接电流/A	110	钨极角度/（°）	60
焊接时间/s	10	弧长/mm	3
钨极直径/mm	2	气体流速/（L·min^-1）	8

名称	取值或描述
分辨率/nm	0.05~0.18
波长/nm	200~1 100
探测器	CCD线性阵列，3 648像素
杂散光	0.04%，取决于光栅
灵敏度	每积分时间160 000次计数
AD转换器	16 bit，1 MHz
采样速率	每扫描周期3.7 ms
积分时间/ms	4

波长/mm	相对强度	跃迁几率/10⁷s^-1	统计权重	激发态能量/eV
458.98	2 810	6.64	6	21.127 0
460.95	3 232	7.89	8	21.143 0
465.79	3 030	8.92	2	19.801 0
472.68	4 278	5.80	4	19.762 0
473.59	4 929	5.80	4	19.261 1