Effect of Al on the Microstructure and Properties of Fe-Cr-C-N System Surfacing Alloy

In this paper, Fe-Cr-C-N-Al surfacing alloy was prepared on Q235 steel plate by open-arc surfacing with self-shielded flux-cored wire. The effects of aluminum content on the microstructure and mechanical properties of the surfacing alloy were investigated by XRD, SEM, EDS, microhardness test, and wear experiment. The results show that the microstructure of the surfacing alloy mainly consists of martensite M, retained austenite gamma-Fe, M7C3 eutectic carbide, and AlN hard phase. When the Al content is 3.77 wt.%, the microstructure of the surfacing alloy is significantly refined, and the precipitation amount of AlN and M7C3 eutectic carbide is the largest and distributed uniformly. The highest microhardness of the surfacing alloy is 657HV(0.5), and the lowest wear weight loss is 0.198 g. Compared with that of 2.77 wt.%, the hardness and wear resistance increased by 50.77 and 68.77%, respectively.