Five different types of hull steel were immersed in 3%NaCl solution for one year; the morphologies of inner and outer rust layers and the corrosion morphologies were obtained by metallographic microscope; and the corrosion characteristics of steel under rust layer were analyzed. The change in corrosion potential (OCP) were recorded for evaluation of influence of rust layer on corrosion tendency; the rust layer morphology and element distribution in inner layers were analyzed by means of electron probe micro-analyzer (EMPA). Average corrosion rate of steels was got by weight loss calculation. The results showed that outer rust layers have little influence on steels corrosion; the corrosion pits seen from steels corrosion morphology corresponds to defects in the inner rust layers; minimum of average corrosion rate is caused by the enrichment of Cr element in the inner rust layer and matrix cross-interface when steel has higher Ni and Cr content.%选择5种不同类型的船体钢,在3％(质量分数)NaCl溶液中浸泡1a,用金相显微镜观察内、外锈层形貌特征和腐蚀形貌,分析锈层下钢的腐蚀特征；记录自腐蚀电位(OCP)的变化,评价锈层对腐蚀倾向性的影响；利用电子探针(EMPA)分析锈层的形貌和内锈层元素分布；通过计算质量损失得到钢的平均腐蚀速率.结果表明,外锈层对钢腐蚀的影响较小；内锈层的缺陷与钢腐蚀形貌中的腐蚀坑对应；当钢中的Ni和Cr元素含量较高时,由于Cr元素在其内锈层和基体交界面富集,其平均腐蚀速率最小.
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