涡流技术用于钢管涂层测厚的可行性研究

Research on Applicability of Eddy Current Testing Technique to Thickness Measurement of Coating in a Steel Pipe

针对目前钢管的激光涂层测厚系统不易保证定位精度,装置调节耗时及检测效率较低等缺点,提出了利用涡流检测技术检测钢管涂层厚度的策略和方法,为不锈钢曲面结构的涂层厚度测量提供了一种有效的检测手段.通过数值仿真研究了涡流检测技术用于涂层厚度测量的可行性,提出了基于数据库的探头提离定量方法.设计了一种大量程涡流探头,解决了涡流测厚探头在检测较厚涂层时量程过小和检测精度不足的问题,管材曲率和厚度对探头信号的影响问题以及涡流信号的非线性问题.仿真结果表明:使用涡流检测方法检测钢管内壁10mm厚度的涂层,其测量精度可达到0.01mm,能满足工程实际需要.

To overcome the disadvantages such as precision of orientation difficult to assure,device regulation consuming time,and low examination efficiency etc existed in the laser thickness measurement system used at present,the eddy current nondestructive evaluation method and strategy for the coating thickness measurement was proposed which provided an effective evaluation tool for thickness measurement of stainless steel contoured structure coating.By using the numerical simulation,the applicability of Eddy Current Testing Technique to thickness measurement of coating in a steel pipe was investigated.A method of probe lift-off was proposed,which was based on database.A wide range sensor was designed and the difficulties of narrow measuring range,low precision,the influences of curvature and thickness on the probe signals and nonlinearity of eddy current signals were solved.The simulation results show that the measure precision of the eddy current sensor for liftoff can reach 0.01 mm,when using Eddy Current Testing Technique to test the thickness of the steel pipe which coating thickness of inner wall is 10 mm,which could meet the demands of practical engineering.