不锈钢在聚甲醛装置模拟介质中的腐蚀行为

目的筛选更为先进的聚甲醛装置升级改造用钢,研究316L,904L和2507不锈钢在聚甲醛装置模拟介质中的腐蚀行为。方法在模拟介质中对这三种不锈钢进行全浸试验,利用动电位极化技术测定它们的点蚀电位,并观察、分析腐蚀形貌和腐蚀产物。结果模拟介质中,316L不锈钢发生点腐蚀和成分选择性腐蚀,腐蚀产物主要为Fe-Cr铁素体相和Fe2O3赤铁矿相。结论904L不锈钢的腐蚀速率和点蚀敏感性均明显优于316L不锈钢,选用904L不锈钢将有助于提升聚甲醛装置的耐腐蚀性能。

Corrosion Behaviors of Stainless Steels in Simulated Poly Formaldehyde Unit Solution

Objective Corrosion behaviors of 316L, 904L and 2507 stainless steels were studied in the simulated poly formaldehyde unit solution, in order to select a more advanced steel for the upgrade of poly formaldehyde unit. Methods Immersion tests were performed for the three types of steel in the simulated solution, pitting potential was measured using the potentiodynamic polarization technique, and the morphology and the phase of the corrosion layer were observed and analyzed. Results Pitting corrosion and selective phase corrosion of 316L stainless steel occurred in the simulated solution, and the corrosion products were mainly Fe-Cr ferritic phase and Fe₂O₃ hematite phase. Conclusion The results showed that owing to the lower corrosion rate and sensitization on pitting corrosion than 316L stainless steel, 904L stainless steel is expected to improve the corrosion resistance of the poly formaldehyde unit.