Comparative analysis of corrosion failure in Q450AWR5 and Q450NQR1 weathering steels under wet coal haulage conditions

To advance the engineering application of next-generation weathering steels for railway vehicles, this study systematically evaluated the corrosion behavior of Q450AWR5 and Q450NQR1 steels using multi-scale analytical methods. By integrating ten-year in-service corrosion data from actual vehicles with laboratory accelerated corrosion test results, a comprehensive assessment of the corrosion performance of these two steels was conducted. The results show that Q450AWR5 exhibits a significant comprehensive performance advantage, and its accelerated corrosion weight loss rate is about 10% lower than that of Q450NQR1. X-ray diffraction (XRD) analysis confirms that the proportion of α-FeOOH in the rust of Q450AWR5 is higher than that of Q450NQR1, and that the proportion of γ-FeOOH is lower than that of Q450NQR1. Under the synergistic effect of corrosion and wear, the average corrosion resistance of Q450AWR5 is ~2.5 times that of Q450NQR1. The average cross-sectional area of Q450AWR5 (516.6 μm²) is only 52.1% of that of Q450NQR1 (992.3 μm²), and the average depth of wear track of Q450AWR5 (0.63 μm) is only 30.1% of that of Q450NQR1 (2.09 μm) as shown by white light interference 3D reconstruction. This study provides key data to support the selection of weathering steels for severe service environments.