通过对过热器管道向火面和背火面的力学性能、 爆口处金相组织、 裂纹与组织的关系及氧化层的分析,得出了300MW过热器锅炉管爆裂失效的原因.结果表明,长期超温运行、 冲蚀、内壁氧化层脱落和局部短时过热综合作用导致过热器锅炉管爆裂发生.利用球化分析法和Larson-Miller参数主曲线外推法,估算了12Cr1MoV材质的过热器锅炉管金属当量温度和剩余寿命,表明锅炉管向火面金属当量温度明显高于背火面,剩余寿命远低于背火面.建议严格控制锅炉运行温度和压力,防止锅炉管局部长时间过热.%The burst failure reason of 300MW reheater boiler tube was obtained by analyzing some aspects, such as the mechanical properties of fire side and back to the fire side, the metallographic structure of burst point, the relationship between crack and structure, and oxide layer. The results indicated that the burst of reheater boiler tube was caused by combined action, including overtemperature operation for a long time, washout, oxide layer shedding from inner wall, and local short-time overheating. Utilizing spheroidization analysis and Larson-Miller parameter master curve to estimate the metal equivalent temperature and remaining life of reheater boiler tube made of 12Cr1MoV material, it showed that the metal equivalent temperature of boiler tube fire side is obvious higher than that of back to the fire side, and the residual life is far lower than back to the fire side. It is suggested the operation temperature and pressure should be strictly controlled to prevent the boiler tube from overheating.
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