Study on cathodic protection criteria of three kinds of Marine high strength steel

摘要

The development and utilization of marine resources are fundamentally dependent on various types of st eel. High -strength steel not only demonstrates exceptional strength but also exhibits a relatively low weight, thereby playing an increasingly pivotal role in the exploitation and utilization of resources within deep-sea environments [1 -2]. The corrosive n ature of seawater is notably high. When high - strength steel is utilized in seawater conditions, cathodic protection is typically essential for mitigating corrosion. However, the enhancement of high -strength steel's strength correlates with an increased sus ceptibility to hydrogen embrittlement [3 -4]. Particularly, when severe overprotection occurs during cathodic protection, it can lead to hydrogen embrittlement in the material [5 -7], presenting a significant risk to the service safety of marine structures. Therefore, investigating the cathodic protection parameters for high -strength steel in marine environments holds considerable importance for preventing both corrosion and hydrogen embrittlement failures [9-10]. In this study, the corrosion protection efficacy of three types of shipboard high-strength steel was evaluated through weight loss corrosion rate testing at various cathodic polarization potentials, while the sensitivity to hydrogen embrittlement of these steels was assessed using slow strain rate te nsile testing (SSRT). The minimum and maximum protection potentials for each type of high -strength steel were established based on their respective protective efficacy and hydrogen embrittlement coefficients. The findings indicate that the cathodic protect ion potential range for 600 MPa -grade steel is -761 mV to -1029 mV(vs.SCE), for 800 MPa -grade steel is -795 mV to -946 mV, and for 1000 MPa-grade steel is -762 mV to -907 mV.