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 (Cr 23 C 6 ), generate the Laves (Fe 2 W) 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.

Non-destructive characterisation of N/Al level in P91 steels using electromagnetic sensors

“…43), and inclusions are mostly effective in pinning domain walls when their size is equivalent to the domain wall thickness. 44 The size of the MX precipitates in the present study (about 40–50 nm in equivalent circle diameter) is within the range for effective size and expected to be in the same order of the domain wall thickness (reported to be ∼39 nm for pure iron). 45 In addition, they are non-magnetic particles containing no Co or Ni and a negligible amount of Fe (three orders of magnitude lower in mass fraction than Nb and V according to Thermo-Calc modelling).…”

Nondestructive Evaluation by Reversible Magnetic Permeability of the Residual Life of Ferritic 9Cr Steel Subjected to Creep-Fatigue Damage

“…Although these materials are designed for superior performance at high temperature, their mechanical strength inevitably decreases, or softens, during exposure to creep and fatigue at elevated temperatures. [1][2][3] Throughout the lifetime of a plant component, the structural material is exposed to various types of loadings and temperatures, and the interaction of various inuences such as cyclic loading and thermal history can change the microstructure and mechanical properties.…”