Abstract

Weld expulsion is one of the most common welding defects during the resistance spot welding (RSW) process, especially for high strength steels (HSS). In order to control and eventually eliminate weld expulsion in production, accurate assessment of the expulsion severity should be the first step and is urgently required. Among the existing methods, real-time monitoring of RSW-related process signals has become a promising approach to actualize the online evaluation of weld expulsion. However, the inherent correlation between the process signals and the expulsion intensity is still unclear. In this work, a commonly used process signal, namely, the electrode displacement and its instantaneous behavior when expulsion occurs are systematically studied. Based upon experiments with various electrodes and workpieces, a nonlinear correlation between the weight of expelled metal and the sudden displacement drop accompanied by the occurrence of weld expulsion is observed, which is mainly influenced by electrode tip geometry but not by material strength or sheet thickness. The intrinsic relationship between this specific signal feature and the magnitude of expulsion is further explored through geometrical analysis, and a modified analytical model for online expulsion evaluation is finally proposed. It is shown that the improved model could be applied to domed electrodes with different tip geometries and varying workpieces ranging from low carbon steel to HSS. The error of expulsion estimation could be limited within ±20.4 mg (±2σ) at a 95% confidence level. This study may contribute to the online control of weld expulsion to the minimum level.

References

References
1.
Zhou
,
K.
,
Shi
,
T.
, and
Cai
,
L. L.
,
2017
, “
Online Measuring the Electrical Resistivity of Molten Nugget of Stainless Steel in Resistance Spot Welding
,”
J. Mater. Process.
,
28
(
8
), pp.
109
115
. 10.1016/j.jmapro.2017.05.026
2.
Jiang
,
D. X.
,
Zhang
,
Q. X.
,
Zhao
,
M.
,
Xia
,
H. B.
,
Wang
,
S. T.
, and
Li
,
Y. B.
,
2019
, “
Effects of Welds Distribution and High-Low Temperature Humidity Alternating Aging on Sealing Performance of Weld-Bonded Stainless Steel Structures
,”
J. Mater. Process.
,
48
(
12
), pp.
77
85
. 10.1016/j.jmapro.2019.10.017
3.
Farson
,
D. F.
,
Chen
,
J. Z.
,
Ely
,
K.
, and
Frech
,
T.
,
2013
, “
Monitoring of Expulsion in Small Scale Resistance Spot Welding
,”
Sci. Technol. Weld. Joining
,
8
(
6
), pp.
431
436
. 10.1179/136217103225009071
4.
Senkara
,
J.
,
Zhang
,
H. Y.
, and
Hu
,
S. J.
,
2004
, “
Expulsion Prediction in Resistance Spot Welding
,”
Weld. J.
,
83
(
4
), pp.
123s
132s
.
5.
Karloff
,
A. C.
,
Chertov
,
A. M.
, and
Gr. Maev
,
R.
,
2010
, “
Real-Time Ultrasonic Expulsion Detection and Indentation Measurement in Resistance Spot Welds
,”
Proceedings of 29th Review of Progress in Quantitative Nondestructive Evaluation Conference
,
Kingston, RI
,
July 26–31, 2009
, pp.
1609
1614
.
6.
Zhang
,
H. Y.
,
1999
, “
Expulsion and Its Influence on Weld Quality
,”
Weld. J.
,
78
(
11
), pp.
373s
380s
.
7.
Zhou
,
K.
, and
Yao
,
P.
,
2019
, “
Overview of Recent Advances of Process Analysis and Quality Control in Resistance Spot Welding
,”
Mech. Syst. Signal. Process.
,
124
(
1
), pp.
170
198
. 10.1016/j.ymssp.2019.01.041
8.
Zhang
,
H. Y.
,
Hu
,
S. J.
,
Senkara
,
J.
, and
Cheng
,
S. W.
,
2000
, “
A Statistical Analysis of Expulsion Limits in Resistance Spot Welding
,”
J. Manuf. Sci. Eng.-Trans. ASME
,
122
(
3
), pp.
501
510
. 10.1115/1.1285873
9.
Valaee-Tale
,
M.
,
Sheikhi
,
M.
,
Mazaheri
,
Y.
,
Ghaini
,
F. M.
, and
Usefifar
,
G. R.
,
2020
, “
Criterion for Predicting Expulsion in Resistance Spot Welding of Steel Sheets
,”
J. Mater. Process. Technol.
,
275
(
1
), pp.
116329
. 10.1016/j.jmatprotec.2019.116329
10.
Hwang
,
I. S.
,
Kang
,
M. J.
, and
Kim
,
D. C.
,
2011
, “
Expulsion Reduction in Resistance Spot Welding by Controlling of Welding Current Waveform
,”
Procedia Eng.
,
10
(
4
), pp.
2775
2781
. 10.1016/j.proeng.2011.04.461
11.
Su
,
Z. W.
,
Xia
,
Y. J.
,
Shen
,
Y.
, and
Li
,
Y. B.
,
2020
, “
A Novel Real-Time Measurement Method for Dynamic Resistance Signal in Medium-Frequency DC Resistance Spot Welding
,”
Meas. Sci. Technol.
,
31
(
5
), p.
055011
. 10.1088/1361-6501/ab6673
12.
Ma
,
C.
,
Bhole
,
S. D.
,
Chen
,
D. L.
,
Lee
,
A.
,
Biro
,
E.
, and
Boudreau
,
G.
,
2013
, “
Expulsion Monitoring in Spot Welded Advanced High Strength Automotive Steels
,”
Sci. Technol. Weld. Joining
,
11
(
4
), pp.
480
487
. 10.1179/174329306X120895
13.
Fan
,
Q. Y.
,
Xu
,
G. C.
, and
Gu
,
X. P.
,
2016
, “
Expulsion Characterization of Stainless Steel Resistance Spot Welding Based on Dynamic Resistance Signal
,”
J. Mater. Process. Technol.
,
236
(
10
), pp.
235
240
. 10.1016/j.jmatprotec.2016.05.026
14.
Hao
,
M.
,
Osman
,
K. A.
,
Boomer
,
D. R.
,
Newton
,
C. J.
, and
Sheasby
,
P. G.
,
2010
, “
On-Line Nugget Expulsion Detection for Aluminium Spot Welding and Weldbonding
.” SAE Technical Paper, 1, p.
960172
.
15.
Podržaj
,
P.
,
2009
, “
Fuzzy Logic Based Expulsion Detection in Resistance Spot Welding
,”
Proceedings of the 3rd International Conference on Applied Mathematics, Simulation, Modelling, Circuits, Systems and Signal
,
Stevens Point, WI
, pp.
222
225
.
16.
Podržaj
,
P.
,
Polajnar
,
I.
,
Diaci
,
J.
, and
Kari
,
Z.
,
2004
, “
Expulsion Detection System for Resistance Spot Welding Based on a Neural Network
,”
Meas. Sci. Technol.
,
15
(
3
), pp.
592
598
. 10.1088/0957-0233/15/3/011
17.
Luo
,
Y.
,
Wan
,
R.
,
Xie
,
X. J.
, and
Zhu
,
Y.
,
2015
, “
Expulsion Analysis of Resistance Spot Welding on Zinc-Coated Steel by Detection of Structure-Borne Acoustic Emission Signals
,”
Int. J. Adv. Manuf. Technol.
,
84
(
9–12
), pp.
1995
2002
. 10.1007/s00170-015-7846-z
18.
Mikno
,
Z.
,
Pilarczyk
,
A.
,
Korzeniowski
,
M.
,
Kustroń
,
P.
, and
Ambroziak
,
A.
,
2018
, “
Analysis of Resistance Welding Processes and Expulsion of Liquid Metal From the Weld Nugget
,”
Arch. Civ. Mech. Eng.
,
18
(
2
), pp.
522
531
. 10.1016/j.acme.2017.08.003
19.
Xia
,
Y. J.
,
Su
,
Z. W.
,
Li
,
Y. B.
,
Zhou
,
L.
, and
Shen
,
Y.
,
2019
, “
Online Quantitative Evaluation of Expulsion in Resistance Spot Welding
,”
J. Mater. Process.
,
46
(
10
), pp.
34
43
. 10.1016/j.jmapro.2019.08.004
20.
BAOSTEEL
,
2005
,
Cold Rolled Automotive Steel Sheets Product Catalogue
,
BAOSTEEL
,
Accessed 22 September 2020
. http://ecommerce.ibaosteel.com/portal/download/manual/ColdRolled-Automotive.pdf
21.
Xia
,
Y. J.
,
Su
,
Z. W.
,
Lou
,
M.
,
Li
,
Y. B.
, and
Carlson
,
B. E.
,
2019
, “
Online Precision Measurement of Weld Indentation in Resistance Spot Welding Using Servo Gun
,”
IEEE Trans. Instrum. Meas.
,
69
(
7
), pp.
4465
4475
. 10.1109/TIM.2019.2943981
22.
Kong
,
J. P.
, and
Kang
,
C. Y.
,
2016
, “
Effect of Alloying Elements on Expulsion in Electric Resistance Spot Welding of Advanced High Strength Steels
,”
Sci. Technol. Weld. Joining
,
21
(
1
), pp.
32
42
. 10.1179/1362171815Y.0000000057
23.
Mikno
,
Z.
, and
Bartnik
,
Z.
,
2016
, “
Heating of Electrodes During Spot Resistance Welding in FEM Calculations
,”
Arch. Civ. Mech. Eng.
,
16
(
1
), pp.
86
100
. 10.1016/j.acme.2015.09.005
24.
Shen
,
J.
,
Zhang
,
Y. S.
, and
Lai
,
X. M.
,
2013
, “
Influence of Initial Gap on Weld Expulsion in Resistance Spot Welding of Dual Phase Steel
,”
Sci. Technol. Weld. Joining
,
15
(
5
), pp.
386
392
. 10.1179/136217110X12693513264213
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