X60钢在不同温度下的CO_2腐蚀行为

Corrosion behavior of steel X60 at different temperatures

为了研究腐蚀因素与腐蚀速率的关系,通过在NACE溶液(5%NaCl+0.5%CH3COOH)中进行饱和CO2浸泡腐蚀实验,利用失重法、电子显微镜(SEM)和数码相机等方法研究了X60管线钢在30、60和90℃温度条件下的腐蚀行为.研究结果表明,X60钢在90℃条件下的腐蚀速率比在30和60℃条件下高一个数量级,为12.8858mm/a.在30℃时,试样表面无明显点蚀特征,在60℃条件下试样表面仅仅出现点蚀,其余部分平整,而在90℃条件下试样表面不仅出现严重的台地腐蚀而且出现线蚀槽,腐蚀严重.在60℃条件下,点蚀周围富集Cl-,说明Cl-在坑内富集,是引起点蚀成核的主要原因.

In order to investigate the relationship of corrosion factors to corrosion rate, corrosion behavior of steel X60 at 30 ℃,60 ℃,and 90℃ were studied through its quenching in NACE solution （5%NaC1 ＋ 0. 5 % CH3COOH） saturated with CO2 and using weight-lost method, SEM, digital camera,etc. The result showed that the corrosion rate of steel X60 at 90 ℃,was greater than that at 30 ℃ and 60 ℃,by unity order of magnitude,being 12. 885 8 rnm/a. There was no evident pitting corrosion on the surface of specimen at 30 ℃ ;at 60 ℃ the pitting only appeared on the surface and the remainder area was smooth; at 90 ℃ there appeared not only severe mesa attack but also linear corrosion dents, and the corrosion was severe. At 60 ℃, the phenomenon that Cl^- enriches around the pitting manifested that Cl^- enriches also within the pits and become the origin of pitting nucleation.