The Impact Abrasive Wear Resistance and Mechanical Properties of In Situ NbC-Reinforced H13 Steel Composites

H13 steel is a common material for the cutter ring of tunnel boring machines, and it can affect the engineering cycle due to its high wear loss during work. In order to improve the wear resistance of the H13 steel, NbC-reinforced H13 matrix composites were prepared through in-situ casting method. The results showed that the NbC phase had a reticular structure when the content of NbC was 1 vol.%. It gradually changed from such structure to rod-like and granular as the content was increased to 3 and 5 vol.%, respectively. The hardness and elastic modulus of NbC reached the maximum of 8.1 +/- 0.9 and 246.8 +/- 6.7 GPa, respectively. As its content grew higher, it reduced the mechanical properties of the composites, whose yield strength and elongation were 266.7 MPa and 2.6%, respectively. The high-stress impact abrasive wear tests showed that the wear resistance of the composites was at least 1.12 times higher than that of the NbC-free H13 composite. The wear mechanisms of the composites were micro-cutting and fracture spalling of NbC.