Abstract: In order to increase the wear resistance and the deformation resistance of high manganese steel crossing, mechanical impact pre-hardening is carried out on the work surface of high manganese steel crossing. The mechanical impact hardening process optimized for high manganese steel crossing service is as follows： heating the surface of high manganese steel crossing to 300 ℃, and then using a self-made device to impact the surface of high manganese steel crossing. Each hardened point is impacted for ≥ 10 s, and the edge distance of each hardened point is ≤ 3 mm. The hardened depth of high manganese steel crossing is more than 15 mm after the mechanical impact hardening with the surface hardness of 48 HRC. The decreasing of hardness from surface to interior is gentle which results from the decrease of yield strength after the high manganese steel crossing is heated to 300 ℃, and the increase of thickness of the plastic deformation region after the mechanical impact. At the same time, because dynamic recovery occurs in microstructure of high manganese steel during the process of impact deformation at 300 ℃, the surface hardness of the crossing is decreased, so that the hardening result is more suitable for the service conditions of railway crossings. The service lifetime of the high manganese steel crossing is obviously improved after the mechanical impact hardening.

Key words: High manganese steel crossing, Mechanical impact, Pre-hardening