Microstructural and abrasive characteristics of high carbon Fe-Cr-C hardfacing alloy

A series of high carbon Fe-Cr-C hardfacing alloys were produced by gas tungsten arc welding (GTAW). Chromium and graphite alloy fillers were used to deposit hardfacing alloys on ASTM A36 steel substrates. Depending on the four different graphite additions in these alloy fillers, this research produced hypereutectic microstructures of Fe-Cr phase and (Cr,Fe)(7)C-3 carbides on hard-facing alloys. The microstructural results indicated that primary (Cr,Fe)(7)C-3 carbides and eutectic colonies of [Cr-Fe+(Cr,Fe)(7)C-3] existed in hardfacing alloys. With increasing the C contents of the hardfacing alloys, the fraction of primary (Cr,Fe)(7)C-3 carbides increased and their size decreased. The hardness of hardfacing alloys increased with fraction of primary (Cr.Fe)(7)C-3 carbides. Regarding the abrasive characteristics, the wear resistance of hardfacing alloys were related to the fraction of primary (Cr,Fe)(7)C-3 carbides. The wear mechanism was also dominated by the fraction of primary (Cr,Fe)(7)C-3 carbides. Fewer primary carbides resulted in continuous scratches worn on the surface of hardfacing alloy. In addition, the formation of craters resulted from the fracture of carbides. However, the scratches became discontinuous with increasing fraction of the carbides. More primary carbides can effectively prevent the eutectic colonies from the damage of abrasive particles. (C) 2009 Elsevier Ltd. All rights reserved.