LZH-led DIOMAR project to develop new laser welding processes for thick sheet metal in the maritime sector.  

Shipshape: More efficient, cheaper laser welding of thick metal for shipbuilding. 

With improved performance and cost-cutting being key objectives, the further development of thick metal sheet welding is a particular interest of shipbuilding and other maritime engineering industries. 

Now Laser Zentrum Hannover (LZH) together with companies Held Systems Deutschland, Laserline and Meyer Werft, now wants to establish robust, pure laser welding processes for steel sheets up to 30 mm thick. For this purpose, diode laser beam sources will need to be brought to peak performance, say the partners. 

LZH comments that the processes for joining maritime steel components “have a great development potential in terms of production costs and productivity”: the frequently used submerged arc welding is comparatively slow and involves significant workpiece distortion. Laser-arc hybrid welding, as an alternative process, requires labor-intensive edge preparation and is not very flexible. 

Particularly for large steel sheet thicknesses in the range of 12 millimeters to 30 millimeters, no method has so far been able to prevail against submerged arc welding. The scientists at the LZH now want to change this together with the three industrial partners. 

Pure laser welding 

The scientists want to develop robust, pure laser welding processes, especially for thick metal sheet welding in the maritime sector. For this purpose, the project partner Laserline will realize new diode laser beam sources with a maximum output power of up to 60 kilowatts in continuous-wave mode. The aim of the project is to achieve high-quality joints with high welding speeds. 

The partners want to reduce the costs for edge preparation and the amount of additional material compared to existing joining methods. In that way, the costs shall be reduced eventually. 

Steely determination: DIOMAR project involves LZH and three industrial partners.  

The new processes shall complement or even replace the existing ones. The application-oriented development takes place in parallel in a laser laboratory and in a shipyard-like test environment. This makes it possible to quickly test, evaluate and optimize processes. 

Laser safety 

The partners are particularly keen to develop concepts for ensuring laser safety for very high laser output powers of up to 60 kilowatts. This includes the handling of the expected large quantities of emitted hazardous substances. To this end, the LZH also comprehensively investigates the release of hazardous substances from the laser processing zone. 

The joint project "Thick Metal Sheet Welding by High-Power Diode Lasers for Maritime Applications" (DIOMAR) is being carried out by Meyer Werft, Held Systems Germany, Laserline and the LZH. DIOMAR is funded by the Federal Ministry for Economic Affairs and Energy. 

(From: http://optics.org/news/9/12/3)