采用中性盐雾对X70管线钢进行室温腐蚀, 采用SEM和EDS观察了X70管线钢经盐雾腐蚀处理前后表面微观形貌和化学组成的变化。结果表明, 盐雾腐蚀后试样表面化学元素均匀性和结构完整性均被破坏, 表面点蚀较为严重, 出现了大量的点蚀坑; 腐蚀后试样表面含铁量高, 产生了活性铁原子, 并与腐蚀性介质Cl-发生接触反应, 是盐雾腐蚀发生点蚀主要原因。

The salt spray corrosion testing of X70 pipeline steel was conducted. The changes of morphologies and chemical elements of X70 pipeline steel before and after salt spray corrosion test were observed by SEM and EDS. The results show that pitting corrosion of the sample is relatively serious after the salt spray corrosion, and the uniformity and integrity of the surface of the sample were damaged and many pits were formed on the surface after the salt-spray test. The content of Fe in the sample was high, which could produce active iron atoms. The reaction of active iron atoms with the corrosive medium Cl- ions was the main factor of pitting corrosion.