随着深海平台、海水淡化装置及海洋输送管道等装备的快速发展，金属材料在含氯化物的高流速海洋环境中易发生冲刷腐蚀和点蚀失效，严重影响服役安全与寿命。 铸造双相不锈钢凭借优异的强度、韧性及耐蚀性，被广泛应用于泵阀、 管件及推进系统等关键部位， 但不同等级不锈钢在动态海水条件下的耐蚀差异尚缺乏系统研究。 本文以CD3MN、CE3MN、CD3MWN 3 种双相不锈钢及 CN7MS 奥氏体不锈钢为研究对象， 在青岛海域天然海水中分别进行216 h 的静态浸泡与 10 m/s 冲刷腐蚀试验，旨在揭示不同组织与合金元素对海水腐蚀行为的影响规律。通过表面形貌观察、腐蚀速率测定、三维形貌及能谱分析等手段，系统对比其耐蚀性能差异。 结果表明，静态条件下 4 种钢均表现出良好的钝化稳定性，腐蚀速率约为 0.001 0mm/a，最大点蚀深度为 9.55~13.64 μm；而在冲刷条件下，腐蚀速率和点蚀深度显著增大，其中 CN7MS 腐蚀速率最高(0.405 5 mm/a)，CD3MWN 最低(0.146 1 mm/a)，显示出最优的耐冲刷腐蚀性能。

With the rapid development of deep-sea platforms, seawater desalination systems, and marine transport pipelines, metallic materials operating in chloride-containing high-velocity seawater environments are prone to erosion-corrosion and pitting damage, which critically affects their service safety and lifespan. Cast duplex stainless steels, which combine excellent strength, toughness, and corrosion resistance, are widely used in key components such as pumps, valves, and propulsion systems. However, systematic comparative studies on the corrosion behavior of different grades of stainless steels under dynamic seawater conditions remain limited. On this basis, three duplex stainless steels (CD3MN, CE3MN, and CD3MWN) and one austenitic stainless steel (CN7MS) were tested through 216 h of static immersion and 10 m/s erosion-corrosion experiments in natural seawater from the Qingdao area to elucidate the effects of microstructure and alloying elements on corrosion behavior. Surface morphology observations, corrosion rate measurements, 3D surface profiling, and energy-dispersive spectroscopy analyses were performed to comprehensively evaluate the corrosion resistance of the samples. The results show that under static conditions, all four steels exhibit excellent passivation stability, with corrosion rates of approximately 0.001 0 mm/a and maximum pitting depths ranging from 9.55 to 13.64 μm. Under erosion conditions, both the corrosion rate and pitting depth increase significantly, with CN7MS showing the highest corrosion rate (0.405 5 mm/a) and CD3MWN the lowest (0.146 1 mm/a), indicating superior erosion-corrosion resistance.