基于激光热成像方法的奥氏体钢表面缺陷表征

Characterization of surface defects in austenitic steel based on laser thermal imaging

有源热成像是当今广泛使用的无损检测方法,可利用材料热特性完成缺陷表征。本文使用激光作为热成像的激励源,使用激光局部加热试件,产生的球形热流允许以任意方向检测缺陷。在加热过程中,能量扩散完全覆盖缺陷区域,在散热过程中,缺陷的存在会使得激光器的热足迹呈现不对称性,红外热像仪实时监测表面温度场分布,实现表面缺陷的可视化检测。通过实验验证以及对实验结果的图像分析来完成缺陷表征,结果表明:在散热过程中,红外热像仪可实现对缺陷的可视化检测,通过图像锐化处理检测缺陷边界,得到缺陷的形状分布,完成缺陷的定位表征。

Active thermal imaging is a widely used non-destructive testing method that uses material thermal properties to characterize defects.In this paper,a laser is used as the excitation source for thermal imaging.The laser is used to locally heat the test piece,and the generated spherical heat flow allows the defect to be detected in any direction.During the heating process,the energy diffusion completely covers the defect area.During the heat dissipation process,the presence of the defect causes the thermal footprint of the laser to exhibit asymmetry.The infrared thermal imager monitors the surface temperature field distribution in real time to realize the visual detection of surface defects.Through the experimental verification and the image analysis of the experimental results,the defect characterization is carried out.The results show that the infrared thermal imager can realize the visual detection of the defects during the heat dissipation process,and the defect boundary is detected by the image sharpening process to obtain the shape distribution of the defects,and complete the characterization of the defect.