The effect of microstructure on abrasive wear of a Fe-Cr-C-Nb hardfacing alloy deposited by the open arc welding process

The relationship between abrasive wear resistance and microstructure of a hardfacing alloy based on Fe-Cr-C-Nb system (CNO) was investigated. This material was developed for cladding, by an open arc welding technique, of components subjected to severe abrasive wear. The work undertaken included microstructural characterization and abrasion testing. Microstructural examinations of hardfaced layer showed that the microstructure of the alloy consisted of a large volume fraction of primary niobium carbides randomly dispersed in a eutectic matrix comprised of metastable austenite (γ) and eutectic M7C3 carbides as well as a high volume fraction of primary M7C3. Abrasive wear tests, in low stress and high stress, showed that the developed Fe-Cr-C-Nb hardfacing alloy exhibited improved abrasive wear resistance in comparison with the conventional high carbon/high chromium hardfacing alloy with higher hardness and higher volume fraction of primary M7C3. Owing to its better wear resistance and its relatively low cost, the alloy CNO may be a successful replacement of the more conventional hardfacing material for the refurbishment of components subjected to severe abrasive wear in order to extend their service life.