Investigation of the hydrogen content in the process zone and the resulting hydrogen deposition in the weld metal during underwater wet arc and laser beam welding (WaPro)
Final Report Abstract
Within the framework of the DFG project, fundamental questions regarding hydrogen input during wet arc welding (shielded metal arc welding - SMAW) and laser beam welding under water were investigated during the reporting period mentioned. The aim was to compare the two welding processes with regard to hydrogen generation in the process zone and hydrogen contamination of the weld seam. High-speed recordings and spectral measurements were made for the spatially and temporally resolved detection of hydrogen during welding. During manual electrode welding, hydrogen resulting from the electrolytic dissociation of the water could be detected using the characteristic Balmer lines. This was not possible with laser beam welding due to the merely thermal dissociation of the water and the lack of ionization of the hydrogen. The exact hydrogen loading of the weld seams was determined after welding by means of carrier gas hot extractions. In the laser-welded samples, a hydrogen loading normalized to the weld metal volume of up to 13 ppm was detected. On average, arc-welded samples showed a two to three times higher hydrogen content than laser-welded samples.
Publications
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Detection of diffusible hydrogen during laser beam welding under water. Procedia CIRP, 124, 544-548.
Waßmann, Christoph; Emde, Benjamin; Scheithauer, Thomas; Hassel, Thomas & Wesling, Volker
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Investigation of an alternative method for hydrogen content measurement during laser beam welding under water. Procedia CIRP, 124, 522-525.
Waßmann, Christoph; Emde, Benjamin & Wesling, Volker
