【作者】 王丽芳；

【导师】 李萌盛；

【作者基本信息】 合肥工业大学 ， 材料加工工程， 2004， 硕士

【摘要】 电站锅炉过热器管和再热器管是锅炉内部的主要受热面结构件，它们是否安全稳定地运行直接关系到整个电厂的安危，频繁爆管事故影响了电厂的经济效益和社会效益。锅炉过热器管和再热器管失效机理的分析和寿命的预测是提高电厂机组运行可靠度的有效手段。受淮北发电厂委托，本文对在役300MW机组锅炉内局部高温管段的使用寿命评估。 首先，本文为了提高故障诊断和状态检测的准确性和增强锅炉运行的可靠性，深入探讨了锅炉过热器管和再热器管失效机理和可靠性理论，将管道的寿命损伤通过拟合的Larson—Miller函数进行表征，从而得出各参数对寿命的影响，确认运行温度、工作应力和服役时间是寿命损伤的主要因素。 其次，由于管件的真实使用温度是预测其寿命的关键因素，因此，本文通过对未用管材按照几种不同的加热规范在实验室进行模拟加热，测定其加热后的硬度，找出显微硬度与热强参数的关系。利用“内壁氧化层厚度法”和“显微硬度法”对实验管件的实际使用温度进行了分析和计算。 然后，通过试验研究了过热器和再热器管12Cr2MoWVTiB钢材的金相组织、合金元素对管道寿命的影响，分析了管材在高温长期运行后金相组织和合金元素分布的变化情况，对管材寿命进行定性评估。 最后，根据上述持久强度外推分析法、金相试验研究综合评估了截取在役的过热器和再热器管材的寿命。更多还原

【Abstract】 The tubes of superheater and reheater are the main component of the heat exchangers in power plant boilers. Whether they run safely and stably or not is directly count for much the safe of the whole plant operation. And the frequent tube leakage of heat surface impact upon the economy benefits and the society benefits of the power plant. This paper evaluates the life of the 300MW high temperature boiler tubes that have been being used in Huaibei power plant.The dissertation goes deep into the tube failure mechanism and the reliability theory in order to improve the diagnosis and monitor veracity and tone up the operation reliability. The parameters of the tube life lapse is expressed by the Larson-Miller function and the effect of the parameters on the life is derived. And it is confirmed the operation temperature and the pressure and the service time are the main factors of the life lapse.Then because the real operation temperature of the tube is the critical factor for predicting the tube lifetime, we heat some unused tubes in the lab. Then we measuer the rigidity of them and find the relationship between the hardness and heat - intensity parameter. The paper analylizes and caculates the operation temperature of the tube through the methods of the inner oxide scale thickness and rigidity. On this basis the paper calculates the remain life of the experimental tubes.It is researched that the influence on the tube lifetime of the metallographic structure and the alloy element by testing the superheater and reheater tube which is made of 12Cr2MoWVTiB steel. The metallographic change and the distribution of alloy elements after the tube has run in the high temperature condition for longtime is more believable and franker to evaluate the tubes remain life time.In the end of the dissertation, the lifetime of the experimental superheater and reheater tubes that have been used is evaluated by the methods of sress computation and the metallographic tests.更多还原