目前国内火电机组中,低温再热器和高温再热器等部件穿顶棚位置常采用加装密封套管的结构,与受热面管焊接形成套管焊缝。由于存在根部间隙和应力集中,且处于复杂的温度环境和热膨胀力作用下,套管焊缝位置易产生裂纹并扩展至受热面管,严重影响机组的运行安全。针对该套管焊缝,目前没有合适的手段对该位置裂纹进行有效检测,结合理论分析,采用计算机仿真技术指导相控阵超声检测工艺的制定,实现对套管焊缝的声束覆盖,为现场检测提供了一定借鉴。

At present, in domestic thermal power units, components such as low-temperature reheaters and high-temperature reheaters often use a structure with sealing sleeves installed at the top of the roof, which are welded to the heating surface pipe to form sleeve welds. Due to the presence of root gaps, stress concentration, and the complex temperature environment and thermal expansion force, cracks are prone to occur at the welding seam of the casing, which can extend to the heating surface tube, seriously affecting the operational safety of the unit. There is currently no suitable means to effectively detect cracks at this location for the casing weld seam. Based on theoretical analysis, computer simulation technology was used to guide the development of ultrasonic phased array detection technology, achieving acoustic beam coverage of the casing weld seam, effectively solving this problem and providing some reference for on-site inspection.