Two steel pressure vessels, part of an air compressor unit, failed during hydrostatic test at a pressure lower than proof pressure. Pressure drop and fluid leakage was noted during the test and later investigation revealed through-wall cracks on the shells of each vessel. Experimental and numerical investigation was employed to determine possible causes of failure and to propose a repair method for such vessels. Non-destructive testing (visual and ultrasonic) was performed to check the outer and inner surfaces of the vessel for possible cracks and to measure wall thickness. Optical and scanning electron microscopy was used to inspect crack surroundings and determine the size of the cracks. According to experimentally obtained results, excessive pitting corrosion at the bottom part of the vessel initiated cracks. In order to retain the functionality of the vessel, composite patch repair procedure is proposed. Numerical analysis was performed to determine pressure bearing capacity of the repaired vessel. Also, recommendations for avoidance of failure scenario for considered pressure vessels are given.

两个钢制压力容器，作为空气压缩机装置的一部分，在低于耐压的压力下进行水压试验时发生故障。在测试过程中发现了压降和流体泄漏，后来的调查发现每个容器的外壳上都有穿墙裂纹。实验和数值研究被用来确定故障的可能原因，并为这些容器提出一种修复方法。进行无损检测（目视和超声波）以检查容器的外表面和内表面是否有可能的裂纹并测量壁厚。使用光学和扫描电子显微镜检查裂纹周围并确定裂纹的大小。根据实验获得的结果，容器底部的过度点蚀会引发裂纹。为了保留血管的功能，提出了复合补片修复程序。进行数值分析以确定修复容器的承压能力。此外，还给出了避免所考虑的压力容器出现故障情况的建议。