Phase Composition and Defect Substructure of Strengthening Layer Surfaced on Low Alloyed Steel
The microstructure and microhardness distribution in surface of low carbon Hardox 450 steel coated with alloyed powder wires of different chemical compositions are studied. It is shown that the microhardness of 6-8 mm thickness surfaced layer exceeds that of base metal by more than 2 times. The increased mechanical properties of surfaced layer are caused by the submicro and nanoscale dispersed martensite, containing the niobium carbides Nb2C, NbC and iron borides Fe2B. In the bulk plates a dislocation substructure of the net-like type with scalar dislocation density of 1011 cm-2 is observed. The layer surfaced with the wire containing B possesses the highest hardness. The possible mechanisms of niobium and boron carbides formation in surfacing are discussed.
Mikhail D. Starostenkov, Aleksandr I. Potekaev, Sergey V. Dmitriev and Prof. P. Ya. Tabakov
Y. F. Ivanov et al., "Phase Composition and Defect Substructure of Strengthening Layer Surfaced on Low Alloyed Steel", Journal of Metastable and Nanocrystalline Materials, Vol. 30, pp. 28-33, 2018