Collaboration Takes Laser Welding Underwater

Researchers at Laser Zentrum Hannover (LZH) are working with AMT GmbH, a manufacturer of sensors, microsensors, measuring instruments, and submersible probe systems, to develop flux-cored welding for more efficient underwater welding. The technique would have applications for wind farms, coastal protection structures, and harbors requiring technical underwater constructions.

The LaMeer (laser-assisted metal flux-cored welding underwater) project specifically seeks to develop an alternative to the currently used method of manual electrode welding. The method is relatively simple and inexpensive, though it requires repeated interruption as the diver must frequently replace burned electrodes.

Underwater laser cutting offers enormous potential for the dismantling of reactor vessels. Courtesy of LZH.

With flux-cored welding, the wire can be continuously taken from a wire reel that is then melted, thereby enabling much longer weld seams to be produced. This increases deposition and production rates. With the help of laser radiation, the researchers aim to optimize flux-cored welding.

The eventual goal is to develop laser-assisted metal flux-cored welding as a qualitatively convincing and more efficient alternative for underwater welding.

The laser beam will insert energy into the workpiece in a targeted manner to improve arc ignition and stability. Research on laser beam-arc hybrid welding in an atmosphere has shown that the targeted combination of laser beam and arc in a common process zone allows the arc to be guided precisely, enabling higher process stability and geometric accuracy of the weld seam. Additionally, it allows higher welding seams and layering of weld seams. The researchers want to study the combination of the laser beam and arc in underwater applications. To this end they want to develop and test a welding torch prototype with integrated laser optics.

LZH recently partnered with LMB Automation to develop a laser-based production system for the automated production of brass components in a project called LaserMessing. The project is designing an automatable welding process that combines laser-based deep welding and cored wire processes.

Both the LaMeer project and the LaserMessing project are funded by the Federal Ministry for Economic Affairs and Climate Action.