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2008. . No. 2(40) - Jun 2008, pp. 72-74

Characterization of Cr-Mo Steel After High-Temperature Processing with Magnetic NDE Techniques

Amitava Mitra, J. N. Mohapatra, A. K. Panda, J. Swaminathan, R. N. Ghosh

Modified 9Cr-1Mo steel is a candidate material for pres­sure vessels and piping components. This steel owing to its high temperature strength, good creep resis­tance and excellent corrosion resistance finds potential applications in thermal environments. However, prolonged exposure of these materials under high temperature and stress causes microstructural changes, which ultimately lead to failure of the components. Magnetic hysteresis loop measurement and magnetic Barkhausen emis­sion techniques have been used to assess the ageing and creep behavior of this steel. The microstructural changes in the form of carbide precipitation and carbide growth during ageing and creep have been found to reveal different magnetic signals. A significant change in magnetic property has been observed corresponding to the three different stages of creep damage.
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