Study of Microstructure and (Cr,Fe)7C3 Carbides Characteristics in Hypereutectic Fe-Cr-C Hardfacing Alloy

In this investigation hypereutectic Fe-Cr-C hardfacing alloy with constant ratio of 6C Cr = fabricated by GTAW on AISI 1010 mild steel substrate. OES, XRF, XRD, OM, SEM, EDS, WDS techniques and microvickers method were used for determining chemical composition, hardness and studying the microstructure characteristics. The metallographic examination results indicated that hardface samples had three metallurgical zones with different thickness, compositions, microstructure and microhardness. The microstructure in essential (thicker) zone consisted of primary (Cr,Fe)7C3 Carbides with γ+(Cr,Fe)7C3 eutectic structure. SEM, EDS, WDS examination and microhardness test results indicated that primary (Cr,Fe)7C3 carbides in essential zone, have different size, area density, chemical compositions and microhardness. The size, atomic percent of chromium and microhardness of primary (Cr,Fe)7C3 carbides from substrates to top surface increased and area density of them decreased. In addition volume fraction of eutectic phase and eutectic carbides distance from substrate to top surface increased. Therefore it can be divided essential zone to three metallurgical areas.