Wear and RCF assessment in switch rails for different materials

Abstract

Switch rails are severely loaded components in the railway turnout. This work presents a numerical framework to assess the wear and rolling contact fatigue (RCF) for two different pearlitic switch rail materials. Firstly, a cyclic finite element analysis (FEA) is performed calculating the local loads during the first contact of different wheels on the switch rail. Secondly, local wear and RCF models for the investigated steel grades R350HT and 400 UHC® HSH® are determined and their output is visualized in damage maps. After that, the local contact parameters maximum contact pressure, creepage and contact length are extracted from the FEA considering these different wheel profiles and different rail materials. The calculations deliver local contact loads on the switch surface, which are marked in the damage maps. This allows the comparison of R350HT and 400 UHC in relation to their damage susceptibility. Both show a very similar damage response to the contact loading in the switch rail. Wear and surface RCF are the dominating damage patterns. Subsurface RCF is only predicted for some local cases. In total, 400 UHC® HSH® exhibits a higher resistance against wear and RCF. Regarding the wheel types, the worn wheels are identified as most critical for the damage in the switch rail.