It has been shown that high power welding hardly affects the quality of the seam welds and brings out many defects such as porosities in the material. The aim of the study is to investigate and model the porosities forming and trapping at the end of a laser pulse, in the case of tantalum Nd:YAG laser spot welding. So we focused on the solidification stage of single spot welds and we developped a simple model that helps to understand how little porosities can be trapped in the welded zone. The results are in good agreement with the experimental data observed on tantalum and stainless steel.

Topics
Lasers, Transition metals, Welding
1.
V.V.
Semak
,
J.A.
Hopkins
,
M.H.
McCay
,
T.D.
McCay
,
A Concept for Hydrodynamic Model of Keyhole Formation and Support During Laser Welding
,
ICALEO 1994
, pp.
641
–
650
.
Crossref
Search ADS
 
2.
J. T.
Liu
,
D. C.
Weckman
,
H. W.
Kerr
,
The Effects of Process Variables on Pulsed Nd:YAG Laser Spots Welds: Part I. AISI 409 Stainless Steel
,
Metallurgical Transactions B.
Vol.
24B
, Dec.
1993
, p.
1065
–
1076
.
Google Scholar
 
3.
J.S.
Kim
,
T.
Watanabe
,
Y.
Yoshida
,
Investigation of the Porosity Formation Mechanism in Laser Spot Welding
,
ICALEO 1995
, pp.
1011
–
1017
.
Crossref
Search ADS
 
4.
V.
Semak
,
A
Matsunawa
,
Energy Balance During High Power Beam Welding
,
IIW Doc. IV-679-97
,
1997
.
Google Scholar
 
5.
A.
Matsunawa
,
Defects Formation Mechanisms in Laser Welding and Their Suppression Methods
,
ICALEO 1994
, pp.
203
–
209
.
Crossref
Search ADS
 
6.
A.
Matsunawa
,
J.D.
Kim
,
S.
Katayama
,
Reduction of Porosity and Hot Cracking by Pulse Shaping in Laser Spot Welding of Aluminium Alloys
,
IIW Doc. IV-981-97
,
1997
.
Google Scholar
 
7.
E.
Dumord
,
J.M.
Jouvard
,
D.
Grevey
,
Modelling of Deep Penetration Laser Welding: Application to the cw Nd:YAG Laser Welding of X5Cr.Ni.18-10
,
Laser in Engineering
.
1997
, pp.
1
–
21
.
Google Scholar
 
8.
Y.S.
Touloukian
,
Thermophysical Properties of Matter
. Vol.
4
,
1970
.
Google Scholar
 
9.
Takamichi
,
Roderick
,
I.L.
Guthrie
,
The Physical Properties of Liquids
.
Clarendon Press
,
Oxford
,
1988
.
Google Scholar
 
10.
E.
Dumord
,
Modélisation du Soudage Continu par Faisceau de Haute Energie: Application au Cas du Soudage
, Thèse de doctorat,
Université de Bourgogne
,
1996
.
Google Scholar
 
11.
S.G.
Lambrakos
,
E.A.
Metzbower
,
P.G.
Moore
,
J.H.
Dunn
,
A Numerical Model for Deep Penetration Welding Processes
,
J. Materials Engineerihg and Performance
.
1993
.
Google Scholar
 
12.
F.
Brochard-Wyart
,
JM.
Di Meglio
,
D.
Quere
,
Physique des Surfaces et des Interfaces
,
C.R. Acad. Sc. Paris
, t.
304
, Série II, n°
11
,
1987
.
Google Scholar
 
13.
J.
Taine
,
J.P.
Petit
,
Transferts Thermiques
.
Dunod
,
1995
.
Google Scholar
 
14.
R.
Comolet
,
Mécanique Expérimentale des Fluides
. Tome II, Masson,
1994
.
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1998
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