Abstrakt
We present results of the study of structural features of a novel (introduced in 2013) highly corrosion resistant LC 200 N steel, possessing large and stable hardness up to relatively high temperatures and excellent wear resistance. LC200N is a perspective material which can be considered for possible applications in nuclear installations.
We have employed Scanning Electron Microscopy/Energy Dispersive Spectrometry (SEM/EDS) and micro X-ray fluorescence analysis (XRF) for sample characterisation and check of the element composition. The samples were investigated both in the as-prepared state, i.e. in form of round plates (thickness -0.5 mm) after electro-erosive cutting from original rods as well as after polishing both surfaces.
SEM/EDS unveiled regions with different Cr concentrations in the steel - bulk material with lower Cr concentration and precipitates with considerably higher Cr concentration. Magnetically active ferrite phases as well as non-magnetic austenite were identified in samples by Mossbauer spectrometry via probe 57Fe nuclei.
Contribution of the austenite is only marginal in the non-hardened (annealed/soft) steel, but much higher in hardened one. The complex behaviour of magnetic phase governed by varying number of Cr atoms in the first nearest neighbour shells of the resonant Fe atoms was observed.