Damage behaviour of nickel-based transition welds under cyclic thermomechanical loading

作者：Friedmann Valerie^*; Siegele Dieter

来源：Materials at High Temperatures, 2010, 27(1): 35-43.

DOI：10.3184/096034009X12602974885070

• nickel-based transition joints
• component tests
• microstructure
• damage
• lifetime estimations
• multiaxial rupture criterions

The present study was performed on dissimilar nickel-based transition girth welds on superheater tubes. The results of a testing programme including tube tests under cyclic pressure, axial load and thermal loading with dwell times at 625 degrees C will be presented. The pressure and the axial load were varied between 290 and 480 bars, 0 and 42 kN respectively. For testing times below 8,000 hours, failure occurred in the X10CrMoNbV9-1 tube, however, not at the fusion line to the NiCr20Nb weld metal. However, for the longest testing time of 20,000 hours, high-resolution scanning electron microscope investigations showed significant microstructural changes at the fusion line. Single creep cavities were observed in the interfacial region of the martensitic steel when a crack had propagated there from an oxide notch at the tube surface.

• 出版日期2010-3