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通有含溴离子氮气的３０４ Ｌ不锈钢管，经一段时期的使用后产生了严重点蚀。通过解剖被蚀钢管，采用金相分析，ＳＥＭ 形貌分析及ＥＤＳ成分分析的方法，对本案例点蚀特征进行研究， 发现：蚀孔形核于晶界，并以蚀孔自身扩张和孔内形成次生蚀孔两种方式生长，且蚀孔内壁产生富Ｃｒ 层。最后，就相关的电化学理论进行了探讨，并推测活化态蚀孔内壁的溶解导致了富Ｃｒ 层的产生，而富Ｃｒ 层的存在则是孔内建立局部活化态，次生蚀孔形核的物质基础。
Passing a 304 L stainless steel tube containing bromine ion nitrogen produced severe pitting corrosion after a period of use. By anatomizing the eroded steel pipe, using the method of metallographic analysis, SEM morphology analysis and EDS analysis, the pitting corrosion characteristics of the case were studied. It was found that the pitting nucleation was at the grain boundary and was self-expanding and forming in the pores Secondary etching two ways to grow, and the hole wall to produce rich Cr layer. Finally, the related electrochemical theory is discussed, and it is speculated that the dissolution of the inner wall of the active etching hole leads to the Cr-rich layer. However, the existence of the Cr-rich layer establishes the local activation state in the pores, The material basis.