Paper Title:

Effect of Thermal Aging on the Transformation Temperatures and Specific Heat Characteristics of 9Cr-1Mo Ferritic Steel

Periodical Defect and Diffusion Forum (Volume 279)
Main Theme Phase Transformation and Diffusion
Edited by G. B. Kale, M. Sundararaman, G. K. Dey and G. P. Tiwari
Pages 85-90
DOI 10.4028/www.scientific.net/DDF.279.85
Citation B. Jeya Ganesh et al., 2008, Defect and Diffusion Forum, 279, 85
Online since August, 2008
Authors B. Jeya Ganesh, S. Raju, E. Mohandas, M. Vijayalakshmi
Keywords Calorimetry, Ferritic Steel, Phase Transformation, Specific Heat
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Abstract

The effect of thermal ageing on the heat capacity and transformation behaviour of behaviour of 9Cr-1Mo-0.1C (wt.%) ferritic / martensitic steel has been studied using differential scanning calorimetry (DSC) in the temperature range 473 to 1273 K. It is found that a-ferrite + carbide ® g-austenite phase transformation temperature is only mildly sensitive to microstructural details; but the enthalpy change associated with this phase transformation and especially, the change in specific heat around the transformation regime are found to be dependent on the starting microstructure generated by thermal ageing treatment. Prolonged ageing for about 500 to 5000 hours in the temperature range 823 to 923 K contributed to a decrease in heat capacity, as compared to the normalised and tempered sample. The martensite microstructure is found to possess the lowest room temperature CP among different microstructures.