基于超声导波技术的尿素合成塔不锈钢衬里层缺陷的检测研究

A Study on Defects Inspection for Lining Layer of Urea Reactor Stainless Steel Based on Guided Wave Technique

尿素塔衬里层的背侧缺陷是威胁塔体健康安全的主要因素,目前常规无损检测方法难以对其实现缺陷的快速检出。本文发挥超声导波技术长距离快速扫查的特点,对尿素塔衬里层316L Mod.不锈钢开展了兰姆波检测试验。首先,本文提出了获取频散曲线和波形结构的半解析有限元算法,提供了模态选择和探头选择的依据;其次,对具有不同尺寸的人工缺陷进行了实验研究,根据反射信号绘制出用来缺陷评定和缺陷定位的评估图,分析和评价了兰姆波的检测能力。本文提出的这种检测思路可在其他类似结构的检测中推广应用。

The backside defects of urea reactor lining layer are the main factor threatening the health and safety of the reactor body.At present,it is difficult to detect the defect quickly by conventional NDT methods.According to the characteristics of ultrasonic guided wave technology with long distance and fast scanning,this paper carried out Lamb wave test on 316L Mod.stainless steel lining of urea reactor.Firstly,a semi-analyticalfinite element method is proposed to obtain the dispersion curve and wave structure,which provides the basis for mode selection and probe design;Secondly,the artificial defects with different sizes were experimentally studied,and the evaluation atlas for defect evaluation and defect location was drawn according to the reflected signals,The detection ability of Lamb wave is analyzed and evaluated.The detection idea proposed in this paper can be applied to the detection of other similar structures.