Orientation control of primary carbide in Fe-Cr-C hardfacing alloys

Microstructures of three kinds of high carbon Fe-Cr-C hardfacing alloys with carbon contents of 4.11%,5.16%,6.5% respectively were studied in this paper, and growth orientation of the carbide in the microstructures of the hardfacing layer was investigated by controlling cooling condition. The results show that the carbon contents and cooling conditions play an important role in the formation of the microstructures of the overlayer. Increasing carbon contents or decreasing Cr/C will make the orientation of primary carbide vertical to the surface of the overlayer, and the carbide will become more compact. The cooling condition can control the orientation of primary carbide effectively. By use of water-cooling method the primary carbide tends to the orientation vertical to the surface. When the cooling rate is lower, the primary carbide will grow randomly along any direction.