Q235钢和X70管线钢在北美山地灰钙土中的短期腐蚀行为

通过腐蚀失重速率试验、腐蚀形貌特征的扫描电镜观察和X射线衍射分析以及土壤理化性质分析等手段研究了国产Q235钢和X70管线钢在加拿大中南部的山地灰钙土中实地埋样试验一年后的短期腐蚀行为特征.结果发现Q235钢和X70钢的平均腐蚀速率和最大点蚀深度均比较接近,但Q235钢点蚀密度明显高于X70钢;两种钢的腐蚀产物成分类似,均为FeOOH、Fe₃O₄和Fe₂O₃的复杂混合物,腐蚀产物层不致密,存在明显的裂纹;两种钢表层土壤中均发现较多的硫酸盐还原菌、硫化菌和异养菌,这些菌群的共同作用能够加速腐蚀产物层下局部腐蚀的发生.

Short-term corrosion behavior of Q235 steel and X70 pipeline steel in gray desert soil in North America

The short-term corrosion behavior of Q235 and XT0 steel samples buried for one year in the test trench in a typical mountain sierozem area in Calgary, Canada was investigated by corrosion rate t, corrosion characteristic observation and analysis through scanning electrochemistry microscopy and X-ray diffraction, and soil physical and chemical properties analysis. It is found that Q235 steel has a close average corrosion rate and maximum pitting corrosion depth to X70 pipeline steel, but the former has an obviously higher pitting density than the latter. The corrosion products of these two metals are similar and mainly composed of FeOOH, Fe₂O₃ and Fe₃O₄, and the corrosion product layer is loose with cracks and not able to prevent these metals from corrosion. There are multiplex bacteria, such as sulphate reduction bacteria (SRB), sulphate oxidation bacteria (SOB) and heterotrophic bacteria in the soil attaching to the two steel samples, which are in cooperation to accelerate the occurrence of localized corrosion under the corrosion product layer due to the effects of their metabolic actions on corrosion processes.