Influence of the welding procedure on the fracture toughness of duplex stainless welded joints

The effect of different welding conditions on the fracture toughness of a duplex stainless steel welded joint has been studied. The different results are compared with those obtained in the parent steel in both longitudinal and transverse directions. Fracture toughness characterization was carried out by means of impact and crack tip opening displacement tests. Parent steel specimens exhibit a marked change in toughness with the testing temperature. However, SMA weld metal toughness is scarcely affected by the testing temperature being clearly lower. GMAW-PA weldments also exhibit a change in the fracture mechanism which produces a marked transition curve even if a considerable level of toughness is achieved at the whole range. Finally, due to the very large volume fraction of ferrite present in the EB weld metal cleavage fracture is promoted at relatively high temperature.