The characteristics of grooving corrosion at a welding seam of QT800 coiled tubing were investigated under different conditions by using the conventional immersion test and constant potential accelerated corrosion test, respectively. The results showed that the sensitivity of grooving corrosion of the welded tube, represented by the grooving corrosion factor, was within the acceptable range even after the long-term immersion test. The reasons of the grooving corrosion were analyzed from the microstructure and electrochemical performance of the weld. Compared with the matrix and the heat-affected zone, the fusion line had coarse grains, large corrosion current, and low self-corrosion potential, which played a part in the main reason to induce the groove corrosion effect.

中文翻译：

---

QT800连续油管开槽腐蚀行为研究

通过常规浸没试验和恒电位加速腐蚀试验，分别研究了在不同条件下，QT800连续油管焊缝的开槽腐蚀特征。结果表明，即使经过长期的浸没试验，用开槽腐蚀因子表示的焊管开槽腐蚀敏感性仍在可接受的范围内。从焊缝的组织和电化学性能分析了切槽腐蚀的原因。与基体和热影响区相比，熔合线晶粒粗大，腐蚀电流大，自腐蚀电位低，这是引起槽腐蚀的主要原因。