RT Journal Article
SR Electronic
A1 Rehorek, Jakub
T1 Effect of PWHT of X6Cr-NiNbN 25-20 Steel on the Evolution of the Sigma Phase during Creep Exposure at 700 °C
JF Manufacturing Technology Journal
YR 2023
VO 23
IS 6
SP 893
OP 899
DO 10.21062/mft.2023.091
UL https://journalmt.com/artkey/mft-202306-0010.php
AB Superheaters and reheaters made of heat-resistant austenitic steels are being replaced in existing fos-sil fuel power plants to operate at Advanced Ultra Super Critical (A-USC) parameters of steam. New-ly developed and used high nickel content austenitic steels, such as in X6Cr NiNbN 25-20, are pre-dicted to significantly suppress the precipitation of a hazardous σ-phase during long-term creep expo-sure. The σ-phase causes premature failure of the component during creep, which is usually support-ed by a local change in hardness in the case of welded assemblies. Experimental results show that PWHT significantly improved reduction of area. However, for the PWHT specimen with a shorter exposure time of 15,712 hours, there was an acceleration in the precipitation of σ-phase particles dur-ing creep at 700 °C compared to the specimen in the AW state, after 20,557 hours.