Accelerated corrosion characteristics and their relationship with atmospheric corrosion of Q370qENH weathering steel

Abstract

Weathering steel, particularly Q370qENH, is widely used in bridge construction in China due to its exceptional corrosion resistance and low maintenance costs. However, further study is needed on accelerated corrosion simulation methods and the corrosion mechanisms of weathering steel bridges in medium corrosivity environments (e.g., C3 level). Therefore, this study focuses on the accelerated corrosion methods, corrosion characteristics of Q370qENH and the relationship between accelerated and atmospheric corrosion. Firstly, the wet-dry salt spray corrosion test is employed to accelerate the atmospheric corrosion of Q370qENH, with test parameters defined based on relevant research and standards. Subsequently, scanning electron microscopy, 3D scanning and X-ray diffraction techniques are used to analyse the morphology and composition of Q370qENH at different stages of accelerated corrosion, exploring the rust layer formation mechanism. Additionally, the weight loss method is applied to assess the amount and rate of accelerated corrosion, leading to the establishment of a predictive model for accelerated corrosion over time. Furthermore, an atmospheric exposure test field has been established in Changsha (C3 level), based on which a predictive model for atmospheric corrosion of Q370qENH is developed. The relationship between accelerated and atmospheric corrosion is derived by comparing the two predictive models.