通过宏观形貌和显微组织观察、化学成分分析、硬度与冲击性能测试等方法，对某电厂循环流化床锅炉TP347H钢再热管的开裂原因进行分析。结果表明：TP347H钢再热器管与鳍片焊接后，熔合线附近组织均匀性变差，局部晶粒粗大，力学性能变差；服役过程中，在焊接残余应力与屏式再热器管振动所产生的附加应力的共同作用下，裂纹在再热器管熔合线附近晶界处萌生；高温服役过程中的氧化反应加速了再热器管的开裂；建议通过用晶粒细小材料替换TP347H钢、优化再热器排布结构等措施防止再热管的开裂。

The cracking cause of TP347H steel reheater tube of circulating fluidized bed boilers in a power plant was analyzed by macroscopic morphology and microstructure observation, chemical composition analysis, hardness measurement and impact property test. The results show that after TP347H steel reheater tube was welded with fins, the metallographic uniformity near the weld bond decreased, and the grains in local area coarsened, resulting in the poor mechanical properties. During the service process, the crack initiated at the grain boundaries near the weld bond of the reheater tube under the combined action of the welding residual stress and the additional stress generated by the platen reheater tube vibration. The oxidation reaction during high temperature service accelerated the cracking of the reheater tube. It was recommended to replace the TP347H steel with fine grain materials and optimize the structural arrangement of the reheater to prevent the reheater tube from cracking.