Page 388 - Practical Design Ships and Floating Structures

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GMA-process was an obvious answer. Several ways of combination were tested, of which the Hybrid
Laser-GMA welding process showed the most significant advantages with respect to the mentioned
tolerances and also regarding process stability and output performance.
The method shows very promising results again with thin plates (5-7mm) where welding speeds of
more than 2 dmin can be achieved for one side hll penetration welds. A typical process example is
shown in figure 6.
The hybrid welding process can also be applied to fillet welding resulting in reduced angular
distortions.
At this point in time one can state that Laser Hybrid welding with C02-Lasers and MAG is at the
beginning of being state of the art.

Torch Torch
Laser beam I Laser beam

Process coupling =
Process combination
‘Hybrid Welding
..
Figure 5: C-laser Processes
I Laser beam welding I
Hybrid Laser-MIG process with filler metal wire

Laser power: 6kW
Parent metal: Ck 45
Plate thickness: 6mm
Filler metal wire: Ni; 1,Zmm
Feed direction: backward

1.0 mrn 4- Gap width (parallel sidewalls) -+ 0,5 mm
2.6mhin 4- Welding speed ,-+ 1 mlmin
13.8 mhin 4-, Wire feed rate ,-+ 2.7 mlmin
7.9 kW +- Power source rating
321 kJ/m 4- Energy input per unit length of weld -) 360 kJ/m

Figure 6: Comparison of Hybrid Welding with Laser Welding

The disadvantage of the CO2-Laser is and will remain the relatively complicated beam handling
systems. Due to its wave length of 10,6 lm the light can only be transmitted via mirror systems. This
precludes the use of robots in large work spaces like in shipbuilding due to an excessive mechanical
complexity of the beam handling systems.