439超纯铁素体不锈钢耐蚀性评价

通过盐雾试验、电化学试验和FeCl3点腐蚀试验，并结合扫描电镜，对比研究了439超纯铁素体不锈钢和430普通铁素体不锈钢的耐腐蚀性能。结果表明,碳、氮间隙元素极低的439超纯铁素体不锈钢耐点蚀性能明显优于430普通铁素体不锈钢，虽然430钝化膜修复能力较强，但点腐蚀速率也较快；430不锈钢具有严重的晶间腐蚀敏感性，同样，430普通不锈钢在干湿加速盐雾试验中发生了严重腐蚀，439超纯铁素体不锈钢在上述腐蚀试验中均表现出轻微的腐蚀。可见在430普通不锈钢基础上降低碳、氮间隙元素含量，同时加入钛稳定化元素，使其耐腐蚀性能大幅提高。

Corrosion resistance evaluation of 439 ultra- pure ferritic stainless steel

Combined with the SEM, the corrosion behavior of 439 ultra- pure ferritic stainless steel and 430 ferritic stainless steel has been compared by salt spray test, electrochemical test, FeCl3 point corrosion test. The result shows the pitting corrosion resistance of 439 ultra- pure ferritic stainless steel with extremely low carbon and nitrogen gap elements is better than that of 430 ferritic stainless steel. Although the capability of 430 passive film repair is stronger, the rate of pitting corrosion is faster. And 430 stainless steel has severe intergranular corrosion sensitivity, while 439 stainless steel is slightly lighter. Loop salt spray test shows that 430 stainless steel suffers severe corrosion, and 439 ultra- pure ferritic stainless steel has less corrosion. Therefore, on the basis of general 430, reducing the content of interstitial element carbon and nitrogen and adding the stabilizing element Ti can improve the corrosion resistance greatly.