Assessment of the creep rupture data of the welded joints of P91 steel using several evaluation methods

Abstract EN

The values of creep rupture strength of the welded joints of P91 steel, at 600 and 650°C were evaluated by several evaluation methods.

Those were: (1) direct comparison of the welded joints to the base metal, (2) stress reduction factor, (3) Larson-Miller parameter and (4) lifetime assessment methods.

It was found that the creep rupture strength of the welded joints of P91 steel approaches that of the base metal in short-term creep tests (<2000h).

However, it approaches that of the specimens simulating the fine-grained heat affected zone of the welded joints.

At the same time it is much lower than that of the base metal in the long-term creep tests (>2000h), either at 600 or 650 C which could be related to the drastic microstructural changes that occur during long-term creep tests.