表面机加工对奥氏体不锈钢氧化膜耐腐蚀性能的影响

Effect of Surface Machining on the Corrosion Resistance of Oxide Film of Austenite Stainless Steel

使用不同工艺参数对核电厂广泛使用的304L和316L奥氏体不锈钢进行表面铣削加工,然后在模拟压水堆核电站一回路水环境中进行浸泡氧化试验。对其表面形成的氧化膜进行点蚀和应力腐蚀性能评价。结果表明,虽然随着浸泡时间的延长,不锈钢表面氧化膜的耐蚀性有所增加,但铣削加工会显著降低两种不锈钢氧化膜的耐蚀性。随着浸泡时间的延长,表面形成的氧化膜不能减缓机加工后试样的应力腐蚀开裂,甚至部分氧化膜会因为脆化而加剧应力腐蚀开裂。

Surface milling of 304 Land 316 Laustenitic stainless steels with different processing parameters was carried out,and then immersion tests were conducted in simulated primary loop environmental water of pressurized water reactor nuclear power plants.The pitting corrosion and stress corrosion properties of the formed surface oxide film were evaluated.The results showed that milling could significantly reduce the corrosion resistance of the oxide films on the surface of two stainless steels,although the corrosion resistance of the oxide films increased with the prolongation of immersion test.Stress corrosion cracking of machined specimens could not be alleviated by the formation of oxide film on the surface with prolongation of immersion time,and even stress corrosion cracking of some oxide film was aggravated due to embrittlement.