火电锅炉水冷壁管道失效机制及电磁场修复  

Failure mechanism and electromagnetic field repair for water-wall pipe in fossil-fuel power station

作　　者：黄涛 Huang Tao(Hebei Special Equipment Supervision and Inspection Research Institute,Qinhuangdao 066000,Hebei)

机构地区：[1]河北省特种设备监督检验研究院秦皇岛分院,河北秦皇岛066000

出　　处：《河北冶金》2025年第3期79-84,共6页Hebei Metallurgy

摘　　要：火电厂锅炉炉膛周围或中间的水冷壁可以降低炉墙温度,保障锅炉长期稳定运行。但水冷壁管道长期在高温、高压、较大温度梯度的恶劣环境下服役,是整个火电机组发生故障机率最高的构件,维修成本极大。因此,分析水冷壁管失效原因并探索绿色、高效的修复手段至关重要。通过微观组织表征和有限元模拟计算发现,管道内汽/水混合冷却剂通过弯道处会在下游某处产生涡流,形成温度过热区,长期运行后造成管道局部老化加速,具体表现为晶界开裂、珠光体球化,最终导致爆管失效。随后,在爆管区域取样并通过脉冲电流外场对其进行系列参数处理。硬度检测结果显示,经脉冲电流处理后,材料的硬度随脉冲电流参数增加表现出先上升后下降的规律,在145~174 HV范围内波动。表征结果显示,处理后老化材料的微观组织被显著优化,电子风力和额外的电自由能造成的快速固态相变是导致老化管道“恢复性能”的根本原因。The water-wall near or inside the boiler furnace is used to reduce the temperature of the furnace wall to ensure the long-term stable operation of the boiler.The water-wall pipe is the component with the highest failure probability in the whole fossil-fuel power station,because of the harsh service environment including long-term,high-temperature,high pressure and large temperature gradient,which cause extremely high maintenance cost.Therefore,it is very important to analyze the failure reasons of water-wall pipe and explore green and efficient repair method.Through microstructure characterization and finite element simulation calculation,this paper found that the mixed steam/water coolant in the pipe can produce eddy current somewhere downstream where it passed through the bend,forming a temperature overheat zone,resulting in accelerated local aging of the pipe after long-term operation,which was specifically manifested as grain boundary cracking and pearlite spheroidization,and eventually leading to pipe explosion failure.Subsequently,samples were taken from the exploding area and a series of parameters were processed through pulsed current field.The hardness test results show that the hardness of the material increases first and then decreases with the increase of pulse current parameters,and fluctuates in the range of 145~174 HV.The characterization results showed that the microstructure of the aged material was significantly optimized after treatment,and the rapid solid-state phase transition caused by electron wind force and additional electric free energy was the fundamental reason for the rejuvenation of the aged pipe.

关 键 词：水冷壁 老化失效 温度过热区 涡流 脉冲电流 性能修复 

分 类 号：TM621.2[电气工程—电力系统及自动化]