Using Nd:YAG and Co2-laser, the weldability of zinc coated metal sheets in overlap configuration without gap between the sheets has been investigated. The use of a high speed camera and a CCD camera has allowed to study the characteristics of a pulsed and CW process by visualizing the phenomenon of melt pool ejection. We have observed that the Zn vapor is ejected inside the keyhole through tunnels mainly located in fi-ont of the keyhole. The effect of these tunnels leading to different types of melt pool ejection, is analyzed for each welding condition and the resulting gas jet has been modeled. New results about keyhole and melt pool movements as well as zinc vapor behavior are discussed. Finally, we show that the use of elongated focal spots allows us to correctly weld these sheets in overlap position without a gap.

1.
R.
Imhoff
,
K.
Behler
,
E.
Beyer
 and
D.
Maischner
 “
Laser Beam Welding of Zinc-Coated Sheets and Quality Control
”.
25th ISATA 92’Florence
pp
93
–
101
2.
D.
Radaj
,
R.
Koller
,
U.
Dilthey
,
O.
Buxbaum
,
F.
Welsch
,
D.
Fuest
,
C. M.
Sonsino
,
F.
Müller
,
A.
Rief
,
H.
Hornig
,
K. -P.
Weibel
,
E.
Steib
, “
Laserschweißgerechtes Konstruieren, Beiträge zu innovativen Fertigungsverfahren
”
Daimler Benz Forschungbericht
1993
Google Scholar
 
3.
M. P.
Graham
,
D. M.
Hirak
,
H. W.
Kerr
 and
D. C.
Weckman
 “
Nd:YAG Laser Welding of Coated Sheet Steel
”
Journal of Laser Applications
(
1994
)
6
, pp
212
–
222
https://doi.org/10.2351/1.4745359
Google Scholar
Crossref
Search ADS
 
4.
Heinz
Haferkamp
,
Friedrich-Wilhelm
Bach
 “
Fügen verzinkter Stahlbleche mit Nd:YAG- Laserstrahlung
”
Stahl
pp
26
–
29
5.
Spies
Bernhard
 et al
Mercedes
Benz AG
. “
Überlapp- oder Steg-Schweissnaht für verzinkte Bleche
” Patent EP 0 421 091 AI
6.
Alberta Delle
Piane
 et al “
Method of Laser Welding Sheet Metal Protected by low-Vaporizing-Temperature Materials
” Patent US 4, 682,002
7.
K.
Behler
,
R.
Imhoff
,
E.
Beyer
,
D.
Maischner
,
G.
Herziger
 “
Arrangement for Welding Coated Worpieces Using a Laser Beam
” Patent WO 90/11161
8.
R.
Poprawe
,
Rolf
Klein
 und
Lutz
Abram
, “
Lasertechnick in der Verarbeitung beschichteter Feinbleche
”
Stahl und Eisen
115
(
1995
) n°
7
pp
31
–
37
Google Scholar
 
9.
Thyssen Laser-Technik GmbH
, AachePatent P4407 190.6
10.
S. W.
Williams
,
P. L.
Salter
,
G.
Scott
 and
S. J.
Harris
 “
New Welding Process for Galvanised Steel
”
26th ISATA (International Symposium on Automative Technology and Automation) Proceedings 93’
Aachen
pp
49
–
57
]
11.
Edward J.
Pennington
,
Laser
 “
Welding of Galvanized Steer
” Patent 4 642 446
12.
Umit
Bilge
,
William
C. Jenuwine
 “
Laser Welding Method
” Patent 5 187 346
13.
J.
Heyden
,
K.
Nilsson
 and
C.
Magnusson
.
Lulea
 “
Laser Welding of Zinc Coated Steel
”
Proc. 6th Int. Conf. Lasers in Manufacturing
pp
93
–
104
May 1989
14.
H. -G.
Treusch
,
V.
Krause
,
M.
Niessen
,
J.
Berkmanns
,
E.
Beyer
 “
Welding With a 3 kW-Nd:YAG-Solid-State Laser
”
Laser Treatment of Materials
(
1992
) DGM-Verlag
33
–
38
et
Google Scholar
 
15.
J.
Beersiek
 “
Online Kontrolle und Regelung der Einschweißtiefe beim Schweißen von Stahl mit einem CO2-Laserstrahl
”, Dissertation in
Vorbereitung
,
Rheinisch-Westfälische Technische Hochschule RWTH
,
Aachen
,
1998
.
Google Scholar
 
16.
M.
Kielwasser
 “
Soudage par faisceau laser de tôles revêtues. Analyse des processus physiques et des conditions de mise en œuvre du procédé
”, Thesis of
Université de Strasbourg I
, 26 novembre
1999
.
Google Scholar
 
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