Moessbauer measurements backscattering technique (CXMS) of laser irradiated cold forming tool steel (X210Cr12)

Conversion X-ray Moessbauer measurements (CXMS) in backscattering technique are performed on a commercial cold forming tool steel (X210Cr12), subjected to single-pass laser irradiation. The structure of the affected layer is examined for laser powers ranging from 2700 W to 3050 W at different depths. The results of the spectra analysis are discussed in connection with Vickers hardness and metallographic data. If a complete molten layer is quenched, a high carbon content austenite is retained down to room temperature. This phase is mixed with some low carbon martensite and (Cr0.5Fe0.5)7C3 carbide. The effects of carbon diffusion from the coating medium into the bulk are discussed. It is demonstrated that Moessbauer spectroscopy is a sensitive tool for phase analysis, including information about phase formation, and for delimiting the range of the quenched molten layer after laser treatment. It is thus a promising technique in this special kind of steel engineering. (orig.)