Abstract
A creep test program was undertaken with six tube samples removed from a SMR furnace. The tubes are HP micro alloyed centrifugally cast Fe-Cr-Ni that contains Nb and minor amounts of Ti, Zr, W, and perhaps rare earth elements. Both LMP and Omega creep tests were performed. Initially, this type of material is inherently creep brittle but as soon as it is put in service, the high operating temperatures caused significant increase in creep ductility that occurred at the expense of decreasing creep strength. However, the impact resistance measured by Charpy tests remains as low as as-cast condition. This paper describes the material creep behavior of this alloy in the light of the Omega test parameters and shows the correlations found among all these factors that were measured, as well as with the LMP method.
