pH值对货油舱用耐蚀钢腐蚀特性的影响  

Effect of pH value on corrosion behavior of corrosion resistant steel for cargo oil tank

作　　者：周鼎[1,2] 柴锋[2] 丁汉林[1] 罗小兵[2] 李灏[2] 

机构地区：[1]安徽工业大学材料科学与工程学院,安徽马鞍山243002 [2]钢铁研究总院工程用钢研究所,北京100081

出　　处：《钢铁研究学报》2016年第6期67-73,共7页Journal of Iron and Steel Research

摘　　要：针对油轮货油舱底部的高氯离子强酸性腐蚀环境,参照了IMO《货油舱用耐蚀钢实验程序》的要求,深入研究了腐蚀溶液的pH值对其腐蚀特性的影响,对比分析了普通E36级船板钢以及等强度级别的耐蚀船板钢腐蚀行为的差异。研究结果表明,pH值对钢的腐蚀速率有显著影响。pH<3.0时,耐蚀钢的耐腐蚀性能,尤其是耐点蚀性能明显优于传统钢;pH≥3.0时,耐蚀钢和传统钢的腐蚀速率未表现出明显差异。强酸性氯离子环境下,实验钢的纯净度、微量耐蚀合金设计、显微组织共同决定了其耐腐蚀性能。钢中的非金属夹杂物是诱发局部腐蚀的主要原因;Cu、Ni、Sn元素的复合添加能显著提高耐蚀钢的腐蚀电位,同时耐蚀合金元素在锈层内部富集,提高了耐蚀钢表面锈层的致密性与稳定性;单一均匀的贝氏体显微组织有利于提高实验钢在酸性氯离子环境下的耐蚀性能,这主要是由于贝氏体组织中富碳相较少且分布均匀。According to test procedures for qualification of corrosion resistant steel for cargo tanks of IMO,effect of pH value on corrosion resistant character of bottom of cargo oil tank in environment with strong acid and high Clwas studied.The difference of corrosion behaviors between conventional E36 grade steel and corrosion resistant steel was analyzed.The results show that the corrosion rates of the steels are significantly affected by pH value.When pH value is lower than 3,the corrosion resistance of corrosion resistant steel,especially pitting corrosion resistance is obviously better than that of conventional steel.There is no significant difference between corrosion resistant steel and conventional steel in corrosion rate when pH≥3.In strong acidic media containing Cl-,the steels′corrosion resistances are determined by purity,alloy design and microstructure.Non-metallic inclusion in steel is the main reason for localized corrosion.Addition of Cu,Ni and Sn can significantly increase the corrosion potential of corrosion resistant steel.These corrosion resistant alloy elements concentrate in rust layer,which can enhance the compactness and stability of rust layer for corrosion resistant steel.Single and uniform bainite microstructure could improve corrosion resistance of the steels in environment with strong acid and high Cl-.This is mainly because carbon-riched phase is less and distributes uniformly.

关 键 词：货油舱 PH值 析氢腐蚀 点蚀 Cu-Ni-Sn 

分 类 号：U668.2[交通运输工程—船舶及航道工程] TG174[交通运输工程—船舶与海洋工程]