目的 为了提高超高强度钢耐海洋大气腐蚀的性能。方法 采用室内周期浸润加速模拟腐蚀试验，通过金相显微镜和扫描电子显微镜，观察了低合金超高强度钢的组织和夹杂物的形貌，分析了稀土对组织和夹杂物的影响；采用失重法和电化学阻抗技术分析了腐蚀动力学规律及电化学行为规律。结果 稀土在低合金超高强度钢中具有细化组织和变性夹杂物的作用，稀土增强了锈层的致密性，使得低合金超高强度钢的耐蚀性能显著提高，且随着稀土含量的增加，锈层电阻值逐渐增大，即稀土提高了锈层对基体的保护能力，稀土加入量为0.08%的低合金超高强度钢的耐腐蚀性能最好。腐蚀384小时后，稀土含量为0.08%的低合金超高强度钢的腐蚀质量损失与未添加稀土的低合金超高强度钢相比降低了11.4%。结论 在低合金超高强度钢中添加稀土能够细化组织、变质夹杂物。稀土低合金超高强度钢的夹杂物主要为球形的稀土复合氧硫化物。稀土含量为0.08%的低合金超高强度钢的耐腐蚀性能最好。

Objective in order to improve the performance of ultra high strength steel in marine atmospheric corrosion. Methods the microstructure and inclusion morphology of low alloy high strength steel were observed by means of optical microscope and scanning electron microscope. The effects of re on Microstructure and inclusion were analyzed by means of the method of weight loss and electrochemical impedance. Results the rare earth in the low alloy high strength steel has the effect of refining microstructure and modified inclusion. The corrosion resistance of low alloy high strength steel is improved obviously, and the corrosion resistance of the alloy increases with the increase of the content of rare earth. After 384 hours of corrosion, the corrosion weight loss of the low alloy high strength steel with the rare earth content of 0.08% was reduced by 11.4% compared with that of the low alloy high strength steel. Conclusion adding rare earth elements in low alloy high strength steel can refine the microstructure and metamorphic inclusion. Inclusion of rare earth low alloy high strength steel is mainly spherical. The corrosion resistance of low alloy high strength steel with rare earth content of 0.08% is the best.