Creep testing and microstructural analysis were used to assess the properties and time-dependent deformation behavior of precipitation-strengthened nickel-based alloys, specifically, Inconel® alloy 740 and Haynes® 282® alloy, for use as pressure components in boilers operating under advanced steam conditions (750°C, >35 MPa). In support of the need for extended service of steam boiler tubing, piping and vessels, the ability of simple Larson-Miller estimates and a modified power-law model (Wilshire et al.) to predict creep lifetimes on the order of 105 hours based on experimental data out to almost 50,000 h was evaluated for these alloys. Even under conservative conditions, both Inconel alloy 740 and Haynes 282 project to have creep lifetimes exceeding 100,000 hours at 750°C and 100 MPa.
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