Structural Evolution of 9%Cr Martensitic-Ferritic Steels in Heat Treatments Related to Manufacturing or Service Operations.

Abstract

The influence of the heating rate to austenite and austenitizing temperature on the austenitic grain size distribution was qualitatively studied in simple thermal cycles for an ASTM A335 grade P92 steel, in order to estimate the critical heating rates that result in a heterogeneous grain size distribution. The experiments were conducted using a high-speed, high-resolution dilatometer, and the samples were characterized through optical microscopy. Qualitative relationships were proposed between the austenitization temperature and the critical heating rate for the production of a heterogeneous distribution of austenite grain size.