39
Through Optimum Use and Innovation of Welding and Joining Technologies
Improving Global Quality of Life
Meyer Shipyard in Germany is the first in the world to have a panel line with 4 CO
2
lasers each of 12 kW,
welding large ship panels with up to 20 stiffeners of 20 meters long. The Laser Hybrid MIG Process produces
about 50% of the welding seams. Lately, very promising test results with fibre lasers (
Figure 5.6 and
Figure 5.7
)
by Precitec KG in Germany have been realised. Currently, the high initial investment is the
main obstacle against a laser installation. Additionally there are several types of laser sources CO
2-
,
YAG-,
Direct Diode-, Disc- and Fibre-lasers to choose from. Many experts judge the Fibre laser to have the highest
potential. Independent of laser type the market growth will be a two-digit figure during the coming years.
5.1.5
Friction Stir Welding (FSW)
FSW process, which was invented in 1991 at TWI, is attracting increasing interest and hence many research
institutes are conducting research in FSW with over 60 FSW installations recently installed. About the
same number are running in regular production. The Swedish Al-company SAPA has 7 FSW installations.
The research area is illustrated in
Figure 5.8
.
TWI has invested in the largest FSW machine “POWERSTIR”
in the world, in “PRECISION SPINDLE FSWMACHINE” and “ABB-FSW-ROBOT” to develop the process further.
So far results achieved are:
Single sided linear welds up to 75 mm section in 6082 T6
Pipe girth welding up to 32 mm in Al-7000
Run-off tab technology
Steel thickness of 6 mm, 10 meters welded with v=100 mm/min with one tool in USA
Welded samples of Inconel 600 and Zircalloy 4
Figure 5.5
Schematic showing the coupling
of the laser beam with the tandem process
(
Reproduced courtesy: Fronius)
Figure 5.6
Laser weld, single pass, butt joint
pipeline steel X70, t = 12 mm, laser power
10.2
kW, Welding speed 2.2 m/min
Figure 5.7
Laser hybrid weld, single pass,
Al 6008, t = 8 mm extruded profile, laser
power 10.5 kW, Welding speed 8 m/min
(
Reproduced courtesy: B. Pekkari)
5
Needs and challenges in welding and joining technologies
