Restitution of Prior-Austenite Grain Orientation by Microtexture Analysis of Tempered Martensite Structure in 9Cr-1Mo Ferritic Steel
The 9Cr-1Mo-0.1C steel was solutionzed (1323 K for 1hr) and step cooled (at 40 K/hr between Ms and Mf) to effect martensitic transformation at slower rates, and then subsequently tempered (1023 K for 2 hr). The microtexture of the tempered martensite structure was evaluated using SEM-Electron Back Scattered Diffraction (EBSD) technique, and the crystal orientation data of ferrite crystallites formed within a single prior-γ grain were analyzed in detail. The Kurdjumov-Sachs (K S) orientation relationship (111)γ // (011)α´ [-101]γ // [-1-11]α´ is commonly obeyed in low carbon steels, and a restitution methodology was used to back calculate the orientation of parent γ grain assuming the K-S relationship. The austenite was identified as the common solution of the data set, and its mean orientation has been calculated. The mean deviation from the K-S was calculated to be 3.75º.
Asim Tewari, Satyam Suwas, Dinesh Srivastava, Indradev Samajdar and Arunansu Haldar
M. K. Dash et al., "Restitution of Prior-Austenite Grain Orientation by Microtexture Analysis of Tempered Martensite Structure in 9Cr-1Mo Ferritic Steel", Materials Science Forum, Vols. 702-703, pp. 880-883, 2012