Microstructural Features and Ultrasonic Signal Characteristics of Typical Defects in a Laser Clad Layer
X. Jing, K.Y. Luo, G.F. Sun, F.Z. Dai and J.Z. Lu
The aim of this paper was to investigate the relationship between ultrasonic signal and microstructural feature of typical defects in a 304 stainless steel powder fibre laser clad layer on 316L stainless steel. Three kinds of clad defects, including microcrack, blowhole, and shrinkage or loose structure, were found and analysed through microstructural observations and analyses. Special attention was paid to the typical echo characteristics of different clad defects. Furthermore, the relationship between three kinds of clad defects and the typical characteristics of ultrasonic echo was found, which may provide a novel approach for defect detection and quality evaluation in the laser clad layer.
Keywords: Fibre laser, 316L stainless steel, 304 stainless steel powder, laser cladding, defect detection, microstructure, ultrasonic echo