为了摸清某服役已22 a的海底管道的腐蚀情况和腐蚀机理，选取典型管段，对其进行宏观形貌观察和腐蚀产物的X射线衍射分析。结果表明：该管段内壁以均匀腐蚀为主，虽然存在严重结垢现象，但未发现垢下腐蚀，外壁腐蚀较为轻微，环空内发生了细菌腐蚀。

In order to study the corrosion status and corrosion mechanism of a submarine pipeline which had been in service for 22 years, a typical tube section was chosen for observation of corrosion macrograph and corrosion product analysis by X-ray diffraction (XRD). The results show that the corrosion of the inner wall of the tube section was dominated by uniform corrosion. Although there was serious scaling phenomenon in the inner wall, no corrosion under the scale was found. The corrosion of the outer wall of the tube section was slight, and bacterial corrosion happened in the annulus space.