Dynamic coercivity of advanced ferritic steel during long-term isothermal ageing

Abstract

The object of this study is to characterize the microstructural evolution in advanced ferritic steel for power plant during long-term isothermal ageing by measuring the reversible permeability. Ageing was observed to coarsen the tempered carbide (Cr23C6), generate me Laves (Fe 2W) phase, and reduce the mechanical strength. The dynamic coercivity decreased monotonously during isothermal ageing. The decrease in coercivity physically depends on the domain wall movement, related with the domain wall pinning by nonmagnetic particles and the dislocations. The experimental results show that the dynamic coercivity is very sensitive to the damage accumulations due to isothermal ageing of advanced ferritic steel. © 2009 The Japan Institute of Metals.