Transformation Kinetics of M23C6 Carbide Lattice Parameters in Low Alloyed Steel

Authors

  • Arūnas BALTUŠNIKAS, Irena LUKOŠIŪTĖ, Rimantas LEVINSKAS Lithuanian Energy Institute

Keywords:

power plant steel, carbide, optical microscopy, XRD, lattice parameter, kinetics, JMA, life assessment

Abstract

Power plant steel 12X1MФ, taken from the as-installed condition through to 270000 h service-exposed and accelerated aged in laboratory conditions, have been characterized with optical microscopy and X-ray diffraction. Microscopy showed that during heat treatment a number of microstructural changes occurs. Initially formed pearlite disappeared and carbide coarsening also is detectable in steel exploited for long periods and during accelerated ageing. X-ray diffraction revealed that carbide M23C6 crystal lattice parameter changes as a function of service time or heat exposure in laboratory conditions. Johnson-Mehl-Avrami law was adapted to express the dependence of carbide M23C6 crystal lattice parameter changes in a double logarithmic plot. The obtained linear relationship could be applied for steel real state assessment.

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Published

2010-12-12

Issue

Section

METALS, ALLOYS, COATINGS