奥氏体锅炉管氧化皮堆积厚度脉冲涡流检测

摘要

Austenitic boiler tubes used in power units often suffer from security problems due to accumulation of oxide scales exfoliated from the inside tube wall.In this paper,the pulsed eddy current (PEC)testing technique was presented to quantitatively measure the accumulated oxide-scale thickness.First,an open-close sensor was designed and developed.It was simple in structure and easy to use with good feasibility.Then,a PEC experimental system was established and was applied to measure the accumulated oxide-scale thickness in TP347H tube sample.Finally, experiments were conducted to study the sensor signal characteristics,influence of sensor lift-off and the effect of receiver array.Results show that:the peak value of test signals varies linearly with the accumulated oxide-scale thickness and thus it can be used to accurately quantify the accumulation thickness;the peak value decreases linearly as the sensor lift-off increases;the influence of magnetic transformation of tube wall on measurements can be eliminated by using the peak value of differential signals between array receivers.The results may provide some guidance for the thickness measurement of oxide scales accumulated in austenitic boiler tubes.%针对奥氏体锅炉管内氧化皮堆积带来的机组安全隐患问题,应用脉冲涡流技术对氧化皮堆积厚度进行定量检测.设计并制作了开合式传感器,该传感器具有结构简单、使用方便、通用性较强的优点.构建了脉冲涡流检测试验系统,并将其用于TP347H管样内氧化皮堆积厚度的检测,试验研究了传感器信号特征、提离影响及阵列接收效果.结果表明:检测信号峰值与氧化皮堆积厚度存在线性关系,可用于堆积厚度的准确定量;信号峰值随传感器提离增加而线性减小;以阵列接收信号差分峰值为特征量,可消除服役锅炉管电磁属性转变带来的影响.研究成果可为奥氏体锅炉管氧化皮堆积厚度检测提供应用参考价值.