Abstract: The objective of this work is to characterize the evolution of the microstructure of the ASTM A213 T91 steel, used in power plants of electricity generation, for high temperatures up to 650° C, to optimize the performances of the installations and to reduce the pollutant emissions. The high temperature and pressure inside the boilers promote the microstructural evolution of the martensitic matrix of the T91 by increasing the size of the precipitates by the time exposure. The growth of these precipitates is explained by the absorption of the matrix elements, which will constitue in long term a favorable site for the nucleation of the microcavities; that triggers the creep phenomenon.
An experience has been conducted in the aim of understanding the evolution of the microstructure ofthe steel at a temperature of 550° C. So far, four samples were removed from the furnance for time intervals of: 0, 260, 760 and 1260 hours. Examination by scanning electron microscopy of the martensitic matrix shows a slight increase of the sizes of precipitated M23C6 and stability for MX precipitates.
Keywords: Microstructure, T91 Steel, ASTM A213.
Title: Impact of the Holding Time on the Micro structure of the T91 Steel at High Temperature
Author: Chokri Boubahri, Seifallah Fetni, Jalel Briki
International Journal of Mechanical and Industrial Technology
ISSN 2348-7593 (Online)
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