Effect of weld defects on the mechanical properties of stainless-steel weldments on large cruise ship

AISI 316L stainless-steel is the main material used in large cruise ship, and the quality of the welds significantly affects the service performance of the components. In this study, the effect of weld defects on the mechanical properties of 316L welded joints was investigated. To this end, welds without defects, as well as welds with burnthrough defects and incomplete penetration defects were welded by manual TIG. Subsequently, the microstructure of the weld zone and heat affected zone of the three weld types was characterized, and the mechanical property tests such as tensile, bend, impact, and micro-hardness were performed. Then, the fracture morphology of the welded joints after the tensile and impact tests was observed. The results showed that the weld zone and heat affected zone of the three weld types were all austenite and ferrite structures. Compared to welds without defects, the average ultimate tensile strength of welds with burn-through defects was lower by 2.7% and the average impact strength was higher by 6.5%, the average ultimate tensile strength and average impact strength of welds with incomplete penetration defects was lower by 35.1% and 14.1% respectively. In terms of hardness, the two types of defects had almost no impact on the welds.