Creep fracture behavior of dissimilar weld joints between T92 martensitic and HR3C austenitic steels

The creep fracture of T92/HR3C dissimilar weld joints is investigated. HR3C austenitic steel is welded with T92 martensitic steel to obtain a T92/HR3C weld joint. After welding, creep tests are carried out at 625 °C in the stress range 110–180 MPa. The results indicate that the creep fracture mechanism is dependent on stress. When stresses ≥140 MPa, the fracture location is at the T92 base material and the connection of adjacent dimples results in transcrystalline fracture. For stresses <140 MPa, the fracture location is at the T92 coarse-grained heat affected zone and growth of M₂₃C₆ particles as well as Laves phase (Fe₂(W, Mo)) precipitation on the grain boundaries leads to intergranular fracture.