采用漏磁法可检测抽油杆表面存在的各种缺陷,但对于在现场检测的抽油杆表面却存在油污(虽然经过清洗)、表面粗糙及直线度低(虽然经过矫直)等问题,使得检测过程中的检测探头与被检测的抽油杆接触不严密,造成对微小缺陷特别是疲劳裂纹的检测信号不敏感。研制了拉伸式管/杆漏磁无损检测实验台,对拉伸实验杆预制疲劳裂纹并对其进行了检测试验,结果采集到了更大的疲劳裂纹信号,因此用该方法提高了漏磁法检测抽油杆疲劳裂纹的灵敏度。

The magnetism-leaking method has high sensitivity in detecting the blemish of iron magnetism materials. This method can test different kinds of blemish which exists at the surface of the pole. However,because of the existence of greasy dirt (although has been cleaned),spot roughness,low straight line degree (although has been rectified) on the surface of the pole,the detecting probe and the pole do not contact tightly enough in the course of detection,which makes the detecting signals small,especially on fatigue cracks,it is not sensitive. On the base of manufacturing extended tube and the experiment platform of non-destructive testing,and through pre-fatigue crack and examination experiment,it concludes: the larger fatigue crack signal can be collected by extended detection pole,and the sensitivity improved by using of magnetism-leakig method.