Effect of normalizing treatments on microstructure and electrochemical corrosion properties of U75V-welded joints in an acidic environment

Abstract

Corrosion poses a significant threat to the structural integrity of steel rails, especially in an acidic environment. In this study, we evaluate the corrosion properties of U75V-welded joints using potentiodynamic polarization curves, electrochemical impedance measurements, and corrosion morphology studies under simulated acidic conditions. Compared to non-normalized joints, the normalized joints exhibit a higher self-corrosion current (4.65 × 10−5 A/cm2) and a more negative self-corrosion potential (−0.56919 mV). The smaller and more uniform grain size obtained after normalizing provides multiple active sites on the surface for polarization reactions. Furthermore, owing to significant erosion caused on the rail surface by the acidic solutions, normalizing treatment enhances the passivation effects on the surface, resulting in increased corrosion resistance (221.96 Ω cm2). Our findings provide insights into the impact of normalizing treatments on the corrosion mechanism of U75V rail joints under acidic conditions.

Keywords

• U75V rail
• Flash welding
• Acidic environment
• Normalizing treatment
• Corrosion mechanism