Co-Cr3c2 Coating Incorporating Grain Refinement and Dislocation Density Gradient to Enhance Wear Resistance of 24crnimo Steel

Abstract

High-speed train brake discs, crucial components of the braking system, predominantly fail due to high-temperature wear that critically affects their performance and lifespan.  Here, we introduce a novel method that incorporates ultrasonic shot peening with Co-Cr3C2 particles to create a composite modified layer (referred to as UEG) on the surface of 24CrNiMo brake discs.  Friction test results show that UEG-treated samples maintain a more stable coefficient of friction and exhibit lower wear rates across a temperature range of 25-600°C compared to Untreated samples.  Particularly at 600°C, the wear rate of UEG-treated samples is reduced by 72.3%.  Detailed experiments and analyses have determined that the enhancements in high-temperature stability and wear resistance of UEG-treated samples are due to the presence of grain refinement and a gradient in dislocation density.  These findings suggest that UEG treatment holds substantial potential for improving the high-temperature wear resistance of brake discs, providing innovative insights and approaches for their application.

Keywords: High-speed train brake discs, Modified layer, Surface strengthening, High-temperature friction