Laser ultrasonic testing for near-surface defects inspection of 316L stainless steel fabricated by laser powder bed fusion

• Published in: China foundry Vol. 18; no. 4; pp. 360 - 368
• Main Authors: Dai, Ting, Jia, Xiao-jian, Zhang, Jun, Wu, Jin-feng, Sun, Yi-wei, Yuan, Shu-xian, Ma, Guan-bing, Xiong, Xiao-jing, Ding, Hui
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.07.2021; Foundry Journal Agency; CGN Inspection Technology Co.,Ltd.,Suzhou 215100,Jiangsu,China%Monash (Suzhou) Engineering Technology Co.,Ltd.,Suzhou 215123,Jiangsu,China; School of Materials Science and Engineering,Southeast University,Nanjing 211189,China%School of Power and Mechanical Engineering,Wuhan University,Wuhan 430072,China%CGN Inspection Technology Co.,Ltd.,Suzhou 215100,Jiangsu,China%School of Materials Science and Engineering,Southeast University,Nanjing 211189,China
• Subjects: 3D printing; CT imaging; Engineering; Machines; Manufacturing; Materials Engineering; Metallic Materials; Powders; Processes; Research & Development; Steel, Stainless; China; laser ultrasonic testing; A; additive manufacturing; TG142.71; 316L stainless steel; on-line inspection; non-destructive testing
• ISSN: 1672-6421; 2365-9459
• DOI: 10.1007/s41230-021-1063-1

The laser powder bed fusion (L-PBF) method of additive manufacturing (AM) is increasingly used in various industrial manufacturing fields due to its high material utilization and design freedom of parts. However, the parts produced by L-PBF usually contain such defects as crack and porosity because of the technological characteristics of L-PBF, which affect the quality of the product. Laser ultrasonic testing (LUT) is a potential technology for on-line testing of the L-PBF process. It is a non-contact and non-destructive approach based on signals from abundant waveforms with a wide frequency-band. In this study, a method of LUT for on-line inspection of L-PBF process was proposed, and a system of LUT was established approaching the actual environment of on-line detection to evaluate the method applicability for defects detection of L-PBF parts. The detection results of near-surface defects in L-PBF 316L stainless steel parts show that the crack-type defects with a sub-millimeter level within 0.5 mm depth can be identified, and accordingly, the positions and dimensions information can be acquired. The results were verified by X-ray computed tomography, which indicates that the present method exhibits great potential for on-line inspection of AM processes.