Structural evolution of P92-type martensitic steel during creep at 650 C

Abstract

Microstructure and a dispersion of secondary phase particles were examined in P92-type steel after creep test at temperature of 650 ◦C and an applied stress of 80 MPa in grip, gauge and necked portions of specimens. The structural changes in the gauge and necked sections were characterized by transformation of the tempered martensite lath structure into relatively coarse subgrain one accompanied by the coarsening of M23C6 carbides and precipitation of the Laves phase. No significant effect of creep strain on particle coarsening was found