海洋柔性立管用高强钢的高温海水腐蚀行为

High temperature seawater corrosion behavior of high strength steel for marine flexible pipe

通过开展浸泡腐蚀实验和电化学腐蚀实验研究了海洋柔性立管用高强钢在高温海水环境中的腐蚀行为。通过分析实验钢的腐蚀速率、腐蚀产物物相组成、腐蚀产物形态特征以及不同腐蚀时间后实验钢动电位极化曲线,揭示了实验钢的高温海水腐蚀行为与机制。结果表明:随着腐蚀时间的延长,腐蚀速率先是快速下降随后缓慢下降并趋于稳定,稳定状态的腐蚀速率为0.071 mm/a。而基体表面附着的腐蚀产物的致密度则是随时间的延长不断增加,抑制了腐蚀过程中的电化学反应。钢中耐蚀元素Cr、Mo、Ni的添加不仅可以促进形成致密稳定的腐蚀产物层,还可提高基体的自腐蚀电位,降低自腐蚀电流,增强实验钢的耐蚀性。

The corrosion behavior of high strength steel for marine flexible pipe in high temperature seawater environment was studied by immersion and electrochemical corrosion experiments.The corrosion behavior and mechanism of the tested steel at high temperature were revealed by analyzing corrosion rate,phase composition of corrosion products,morphological characteristics of corrosion products and potentiodynamic polarization curves of experimental steels after different corrosion time.The results show that with the prolongation of corrosion time,the corrosion rate decreases rapidly and then decreases slowly and tends to stabilize,and the stable corrosion rate is 0.071 mm/a.However,the densities of the corrosion products attached to the substrate are increasing with the increase of corrosion time,which inhibits the electrochemical reaction in the corrosion process.The addition of corrosion resistant element Cr,Mo and Ni can not only promote the formation of dense and stable corrosion product layer,but also increase the corrosion potential of the substrate,reduce the corrosion current and enhance the corrosion resistance of the tested steel.