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为探究低合金钢在O2-CO2-SO2-H2S湿气环境中的腐蚀规律和机理,应用基于IMO标准自制的货油舱上甲板环境腐蚀模拟装置,对1种E36级低合金钢的全周期腐蚀行为进行研究。标准腐蚀试验后,测量了不同周期的腐蚀减薄量和腐蚀速率速率,拟合了25年外推腐蚀减薄量计算公式和曲线,观察去除腐蚀产物膜前后的宏观形貌,应用SEM对表层及截面腐蚀产物膜的微观形貌及结构进行分析,通过XRD和EDS分析腐蚀产物膜的物相组成和元素分布。结果表明:IMO标准全周期腐蚀实验后,实验用低合金钢的25年外推腐蚀减薄量为2.21 mm。在腐蚀前期,由温湿交替和酸性气体导致酸性液滴在腐蚀产物膜表层形成,进而形成腐蚀鼓泡;腐蚀后期,腐蚀鼓泡长大并伴随脱落,最终表层腐蚀产物膜全部脱落,内层腐蚀产物膜裸露于腐蚀环境中。腐蚀产物膜外层主要由α-FeOOH、γ-FeOOH、元素S、FeS2、Fe1-xS和FeS组成,结构相对疏松,内层腐蚀产物膜主要由致密的α-FeOOH组成。
In order to explore the regularity and mechanism of corrosion of low alloyed steel in O2-CO2-SO2-H2S moisture environment, the full-cycle corrosion resistance of 1 E36 grade low alloyed steel Corrosion behavior research. After the standard corrosion test, the corrosion reduction rate and corrosion rate rate in different periods were measured. The calculation formula and curve of corrosion reduction after 25 years were fitted. The macroscopic morphology before and after removal of corrosion product film was observed. And the microstructure and morphology of the cross-sectional corrosion products were analyzed. The phase composition and elemental distribution of the corrosion products were analyzed by XRD and EDS. The results show that after the IMO standard full-cycle corrosion test, the 25-year extra-thin corrosion reduction of experimental low-alloy steel is 2.21 mm. At the early stage of corrosion, acid droplets formed on the surface of the corrosion product by the alternation of temperature and humidity and acid gas, forming the corrosion bubbling. In the later stage of corrosion, the corrosion bubbling and growing up accompanied with falling off, Corrosion product film exposed to the corrosive environment. The outer layer of corrosion products mainly consists of α-FeOOH, γ-FeOOH, elemental S, FeS2, Fe1-xS and FeS, and the structure is relatively loose. The inner corrosion product film mainly consists of dense α-FeOOH.