Crack Analysis of Ship Hull Plate during Assembling and Welding Process

A welding crack running through the weld bead and the base metal occurred after assembling and welding of the rear outer ship hull plate. The physical testing and chemical analysis for the parent metal and the macro and micro examination for the cracking section plane were carried out to analyze the cracking cause. The results show that the welding defects and the assembling residual stress caused by the unreasonable welding sequence and welding technique resulted in the generating of crack which expanded from the connection zone of two welds where the stress was rather higher to the parent metal.