There is an increasing need to assess the service life of components containing defect which operate at high temperature. This paper describes the current fracture mechanics concepts that are employed to predict cracking of engineering materials at high temperatures under static and cyclic loading. The relationship between these concepts and those of high temperature life assessment methods is ...

Assessment of creep damage and residual creep life of a cast HP 40 Nb Mod. Reformer tube was performed, wherein the experimental Larson–Miller diagram and area fraction of creep voids were adopted. The state of damage of the tube in service was metallographically analyzed by using light and electron microscopy. Samples from the serviced reformer furnace tube were cut and prepared for void exami...

One of the yet unresolved engineering problems is forecasting the creep lives of weldment in a pragmatic way with sufficient accuracy. There are number of obstacles to circumvent including: complex material behavior, lack of accurate knowledge about the creep material behavior specially about the heat affected zones (HAZ),accurate and multi-axial creep damage models, etc. In general, creep life...

Under the influence of temperature and stresses, the heat resistant materials react by creeping. Boiler components subjected to creep have a limited lifetime. Creep and material structure evolution are tightly related and according to this rule a number of studies have been performed in order to relate micro structural investigation and service exposure or residual life. The determination of th...

The aim of the paper was to examine the influence of repair welded joints on the service life of steam pipelines for over 220 000 hours of service in creep conditions. The research included the study of the microstructure using scanning microscopy, the tests on mechanical properties at room and elevated temperature, determining the nil ductility transition temperature, and short-time creep test...

Hot gas path turbine components are exposed to very severe and complex boundary conditions and many other sources of variation during their design, production, and operation. Consequently, the useful life of these components can exhibit considerable scatter. A complex, multi-physics environment has been created to automate the bulk creep life assessment of a gas turbine airfoil for a land-based...

Gamma titanium aluminides (γ-TiAl) display significantly improved high temperature mechanical properties over conventional titanium alloys. Due to their low densities, these alloys are increasingly becoming strong candidates to replace nickel-base superalloys in future gas turbine aeroengine components. To determine the safe operating life of such components, a good understanding of their creep...