扫描激光线源技术检测金属表面缺陷位置实验研究

Experiment Study on Position Detection of Metal Surface Defect Based on Scanning Laser Line Source

利用扫描激光线源(scaing laser line source,SLLS)技术,提出一种金属表面缺陷位置检测方法,并搭建实验平台,实验研究该检测方法对金属表面缺陷位置的检测效果;方法中利用扫描激光线源技术对样品表面进行扫查,在样品内部激发超声信号,采用双波混合干涉方法实现对激发信号的探测,根据激发的瑞利波和反射回波与缺陷位置的关系,确定激发点和探测点到缺陷的距离,从而确定缺陷的位置;实验研究中分别以线源位置和探测点位置为基点确定缺陷位置,结果表明以探测点位置确定缺陷位置时,定位相对误差为0.23%。

A detection method based on scanning laser line source （SLLS） for metal surface defect position was proposed, and the experimental platform was built to analyse the detection efficiency. The sample surface was scaned by SLLS to excite the ultrasonic signal in the sample, which was detected with two--wave mixing interference detection method. The defect position was located according to the position relationship between the excited Rayleigh wave and the defect, the reflected wave and the defect. In the experiment, the defect position was calculated using the line source position and the detection point position as test reference point respectively. The experiment results show that the relative error is 0.23% in the latter case.