Testing and Analysis of Full-Scale Creep-Rupture Experiments on Inconel Alloy 740 Cold-Formed Tubing

Full-scale pressurized creep-rupture tests were conducted on Inconel^® alloy 740 cold-formed tube bends to evaluate the effect of cold-work on the performance of tube bends for high-temperature creep applications. A new method of analysis is developed that can be used to simplify the complexities of structural (geometric) effects and material degradation due to cold-work. Results show that Inconel^® alloy 740 behaves similarly to other age-hardenable nickel-based alloys subjected to cold-work prior to creep testing with large reductions in rupture life and ductility and a corresponding moderate increase in minimum creep rate. The results also demonstrate that the full-size test method can be a beneficial to understanding the performance of large components in service.