Quick and clean laser welding for thick metal sheets

A new laser-based hybrid welding process developed at the Laser Zentrum Hannover (LZH) makes it possible to weld thick pipelines and metal sheets at greater speed, reducing process costs of liquid gas tanks and pipelines by lowering processing times. It is now possible to weld aluminium alloys or steel at speeds of 6m/min or 1.5m/min respectively.

Scientists of the Joining and Cutting of Metals Group at the LZH have combined a beam from a 16kW solid-state disk laser with two gas metal arc welding (GMAW) torches. A scanner mirror can be used to oscillate the laser beam lengthwise or crosswise to the feed direction.

The process can be used to make single-sided, zero-defect welds for aluminium sheets up to a thickness of 12mm. The joining process can reach feed speeds of 5 to 6m/min, and gaps of up to 0.5mm and edge misalignment of up to 2mm can be bridged. The engineers have also been able to weld steel sheets with a thickness up to 23mm at a speed of 1.5m/mm for single layer welds.

As well as being very fast, the new process gives a seam geometry that is narrow and filler material consumption is considerably lower when compared to conventional methods with multiple layer gas metal arc welding processes.

The joint project ‘HYBRILAS: Welding of thick metal sheets using brilliant laser beam sources’ was part of the ‘MABRILAS initiative: Material processing with brilliant laser beam sources’ and was financially supported by the German Federal Ministry of Education and Research (BMBF), and supported by the Association of German Engineers (VDI-TZ).

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