某台服役年限超50 a的加氢反应器环焊缝上存在5条裂纹和1处埋藏缺陷。采用连续循环加载球压痕法得到材料的力学性能和断裂韧性，并从内壁挖取试样进行理化检验，发现材料的显微硬度无异常，材料晶粒粗大，显微组织无变化，且韧性较好。依据GB/T 19624—2019标准，采用平面缺陷的常规评定方法，同时考虑塑性失效和断裂失效两种机理，计算出5条裂纹和1处埋藏缺陷的评定点均落在双判据法失效评定图的安全区域内。结果表明：该反应器能安全运行3 a。

Five cracks and one buried defect on the girth weld of a hydrogenation reactor with service life over 50 years were found. The mechanical properties and fracture toughness of the material were obtained by continuous cyclic loading ball indentation method, and the samples were excavated from the inner wall for physical and chemical tests. It was found that the microhardness of the material was not abnormal, the grain size of the material was coarse, the microstructure was unchanged, and the toughness was good. According to GB/T 19624-2019 standard, the conventional evaluation method of planar defects was adopted, and the two mechanisms of plastic failure and fracture failure were considered. The evaluation points of five cracks and one buried defect were all located in the safety area of the double-criterion failure evaluation diagram. The results showed that the reactor could operate safely for 3 years.