Zinc coated steels, which provide excellent corrosion resistance, are increasingly used in the automotive industry. Due to the lower boiling point of zinc (906°C) than the melting point of steel (over 1300°C), a highly-pressurized zinc vapor is always produced during zero-gap lap joint laser welding process. In order to weld zinc coated steels in lap joint configuration, a gap with 0.1 mm-0.2mm thick is usually required, which provides a passage for a highly-pressurized zinc vapor to escape.

In this paper, an innovative laser welding technique has been developed to weld zinc coated steels in a zero-gap lap joint configuration. High quality welds were achieved. The key is to consistently produce a stable keyhole assisted by an external vacuum system. Through the stable keyhole, the highly-pressurized zinc vapor was vent out from the faying surface. Mechanical properties of the welds were evaluated by the tensile shear test and hardness measurement. Microstructure is analysed by optical microscopy.

1.
Akhter
,
R.
,
Steen
,
W. M.
, and
Cruciani
D.
 (
1988
)
Laser welding of zinc-coated steel
.
Proceedings of the 5th International Conference on Lasers in Manufacturing
,
Stuttgart, West Germany
,
September 13–14
Google Scholar
 
2.
AWS WZC (D19.0-72)
(
1972
)
Welding Zinc-Coated Steels
,
American Welding Society
.
3.
Dasgupta
,
A.
,
Mazumder
,
J.
 and
Bembenk
,
M.
 (
2000
)
Alloying based laser welding of galvanized steel
,
Proceedings of International Conference on Applications of Lasers and Electro Optics
,
Dearborn MI
.
Google Scholar
Crossref
Search ADS
 
4.
Li
,
X.
,
Lawson
,
S.
 and
Zhou
,
Y.
 (
2007
)
Novel technique for laser lap welding of zinc coated sheet steels
,
Journal of Laser Applications
19
(
4
),
259
–
264
https://doi.org/10.2351/1.2795755
Google Scholar
Crossref
Search ADS
 
5.
Imhoff
,
R.
,
Behler
,
K.
,
Gatzweiler
,
W.
,
Beyer
,
E.
 (
1988
)
Laser beam welding in car body making
.
Proceedings of the 5th International Conference on Lasers in Manufacturing
,
Stuttgart, West Germany
,
Spetember 13–14
Google Scholar
 
6.
Graham
,
M. P.
,
Hirak
,
D. M.
,
Kerr
,
H. W.
 and
Weckman
,
D. C.
 (
1996
)
Nd: YAG laser beam welding of coated sheet steels using a modified lap joint geometry
.
Welding Journal
75
(
5
),
162
–
170
Google Scholar
 
7.
Chen
,
W.
,
Ackerson
,
P.
 and
Molian
,
P.
 (
2009
)
CO2 laser welding of galvanized steet sheets using vent holes
.
Materials and Design
30
,
245
–
251
https://doi.org/10.1016/j.matdes.2008.05.009
Google Scholar
Crossref
Search ADS
 
8.
Gu
,
H.
 and
Shulkin
,
B.
 (
2011
)
A practical use of humping effect in laser beam welding
,
Journal of Laser Applications
23
(
1
),
1
–
6
https://doi.org/10.2351/1.3538988
Google Scholar
Crossref
Search ADS
 
9.
Fong
,
T. Y.
, (
2006
)
Gap-free lap welding of zinc-coated steel using pulsed CO2 laser
.
The International Journal of Advanced Manufacturing Technology
,
29
(
3–4
),
287
–
295
https://doi.org/10.1007/s00170-005-2522-3
Google Scholar
Crossref
Search ADS
 
10.
Xie
,
J.
 and
Denney
P.
 (
2001
)
Galvanized steel welding with lasers
,
Welding Journal
80
(
6
),
59
–
61
Google Scholar
 
11.
Loredo
,
A.
,
Martin
,
B.
,
Andrzejewski
,
H.
 and
Grevery
,
D.
(
2002
)
Numerical support for laser welding of zinc-coated sheets process development
,
Applied Surface Science
195
(
1–4
),
297
–
303
https://doi.org/10.1016/S0169-4332(02)00610-4
Google Scholar
Crossref
Search ADS
 
12.
Iabal
,
S.
,
Gualini
,
M.M.S.
 and
Rehman
,
A.U.
 (
2010
)
Dual beam method for laser welding of galvanized steel: Experimentation and prospects
,
Optics & Laser Technology
42
(
1
),
93
–
98
https://doi.org/10.1016/j.optlastec.2009.05.009
Google Scholar
Crossref
Search ADS
 
13.
Milberg
,
J.
 and
Trautmann
,
A.
 (
2009
)
Defect-free joining of zinc-coated steels by bifocal hybrid laser welding
,
Production Engineering. Research and Development
3
(
1
),
9
–
15
https://doi.org/10.1007/s11740-008-0140-2
Google Scholar
Crossref
Search ADS
 
14.
Kim
,
C.
,
Choi
,
W.
,
Kim
,
J.
 and
Rhee
S.
 (
2008
)
Relationship between the welding ability and the process parameters for laser TIG hybrid welding of galvanized steel sheets
,
Materials Transactions
49
(
1
),
179
–
186
https://doi.org/10.2320/matertrans.MER2007159
Google Scholar
Crossref
Search ADS
 
15.
Gu
,
H.
,
Mueller
,
R.
 (
2001
)
Hybrid welding of galvanized steel sheet
,
20th International Congress on Applications of Lasers & Electro-optics, ICALEO
,
130
–
139
Google Scholar
Crossref
Search ADS
 
16.
Yang
,
S.L.
 and
Kovacevic
R.
 (
2009
)
Welding of galvanized dual-phase 980 steel in a zero-gap lap joint configuration
,
Welding Journal
88
(
8
),
168
–
178
Google Scholar
 
17.
Yang
,
S.L.
(
2009
)
Hybrid laser-arc welding of galvanized high-strength steels in a gap-free lap joint configuration
, Ph.D. thesis,
Southern Methodist University
.
Google Scholar
 
18.
Yang
,
S.L.
,
Carlson
,
B.E.
, and
Kovacevic
R.
 (
2011
)
Laser welding of high-strength galvanized steels in a gap-free lap joint configuration under different shielding conditions
,
Welding Journal
,
90
(
1
),
8/s
–
18/s
.
Google Scholar
 
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