高温下金属材料厚度的激光超声检测研究  

Laser Ultrasonic Evaluation of Metallic Material Thickness at High Temperature

作　　者：郑凯[1] 武兴[1] 李俊燕 倪辰荫[3] 沈中华[2] 马向东[1] 俞燕萍[1] 何君华[1] ZHENG Kai;WU Xing;LI Junyan;NI Chenyin;SHEN Zhonghua;MA Xiangdong;YU Yanping;HE Junhua(Special Equipment Safety Supervision Inspection Institute of Jiangsu Province,Nanjing 210036;School of Science,Nanjing University of Science and Technology,Nanjing 210094;School of Electronic and Optical Engineering,Nanjing University of Science and Technology,Nanjing 210094)

机构地区：[1]江苏省特种设备安全监督检验研究院,南京210036 [2]南京理工大学理学院,南京210094 [3]南京理工大学电子工程与光电技术学院,南京210094

出　　处：《机械工程学报》2021年第10期21-27,共7页Journal of Mechanical Engineering

基　　金：质检公益性行业科研专项(201510068);远东无损检测新技术论坛创新人才支持计划资助项目。

摘　　要：针对高温条件下金属材料厚度测量的问题,使用激光超声技术,首先利用一束脉冲激光在金属材料中扫描激发超声,并使用激光测振仪在固定点探测,获得了从金属样品底面反射的体纵波脉冲信号的渡越时间,随后通过线性拟合获得了样品厚度及体纵波波速,并在室温到480℃的温度范围内实现了多块20号合金钢样品的厚度测量。多温度下、不同厚度的多样品测量结果显示,这一方法的测厚相对误差小于1.5%(样品厚度>10 mm),检测结果较为可靠。这一厚度测量方法与传统基于脉冲回波法的区别在于,这一方法不依赖于纵波声速测量,因此不需要考虑材料内部温度升高时所引起的声速变化。本研究成果可为高温下材料厚度的非接触式高精度测量提供新的解决方案和理论支持。In order to solve the problem of thickness measurement of metal materials under high temperature conditions,laser ultrasonic technique is used to firstly obtain the propagating time of the longitudinal wave pulse signal reflected from the bottom surface of the sample when scanning the excitation light source and fixing the detection source.The sample thickness and bulk longitudinal wave velocity were then obtained accordingly.Afterwards,the thickness measurement of multiple No.20 alloy steel samples was realized in the temperature range from room temperature to 480℃.The multi-sample measurement results with multiple temperatures and different thicknesses show that the relative thickness error of this method is less than 1.5%(sample thickness>10 mm),so that the test results are reliable.The difference between this thickness measurement method and the conventional pulsed-echo method is that this method does not depend on the measurement of the longitudinal wave velocity,so there is no need to take into consideration the change in sound velocity caused by the increase in material temperature.The research results can provide new solutions and theoretical support for non-contact high-precision measurement of material thickness at high temperatures.

关 键 词：激光超声 高温 厚度测量 

分 类 号：TG115[金属学及工艺—物理冶金]