The present work reports the effect of carbonitride precipitates on the solid/liquid erosion behaviour of hardfacing alloy. Two kinds of Fe-Cr13-C hardfacing alloy (with and without nitrogen) were deposited on a carbon steel substrate. The microstructure of the hardfacing alloy was studied. Solid/liquid erosion tests were carried out with quartz sand particles under impact angles of 30 degrees, impact velocity of 25 m/s for 45 min to explore the erosion behaviour of the hardfacing alloy. It is found that the erosion damages of hardfacing alloy were microcutting and impinging caused by the erosion of sand particles. Fine carbonitride precipitates can obviously refine the microstructure and make a dispersion strengthening effect on the matrix, leading to the enhancement of hardness of hardfacing alloy. In addition, lots of carbonitride precipitates can effectively protect the surface of hardfacing alloy against wearing of erosion sand particles. So the erosion resistance of hardfacing alloy could be improved significantly owing to the strengthening and protecting effect of carbonitride precipitates, and solid/liquid erosion mechanisms were found to be microcutting and impinging with shallow grooves, fine pits and tiny lips. (C) 2013 Elsevier B. V. All rights reserved.