Welded joint behaviour under conditions of creep

In assessing the creep behaviour of different zones in a welded joint, two geometries were considered using different filler materials to achieve mis-match conditions. The minimum creep strain rates present in each zone were determined experimentally for a 1.25Cr 0.5Mo parent material. Results obtained were directly employed by FEM code to simulate operating conditions in an element of welded pipe subjected to internal pressures and temperature. For the material under test, undermatching showed that rupture takes place in the base material; conversely, the employment of filler material featuring low creep strain rates leads to very high stress levels in the fusion zone.