Investigations on fatigue strength of wet welded structural steels

The fatigue strength of underwater wet welded constructional details was investigated within this research project. Wet hyperbaric shielded metal arc welding (SMAW) is a widely established repair technique and an approved process in steel hydraulics construction. To date, only little research has been done on the fatigue strength of wet SMAW welds for typical steel grades. To address this issue, weld samples were made fully mechanized in a hyperbaric chamber to experimentally simulate water depth dependent ambient conditions. The resulting weld quality was analysed and the fatigue behaviour in the high cycle fatigue range was investigated by constant amplitude SN testing. This was followed by a statistical evaluation of the characteristic fatigue strength according to Eurocode 3/EN 1993-1-9.