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Ultrasonic C-scan Detection for Stainless Steel Spot Welds Based on Signal Analysis in Frequency Domain

2014; The Iron and Steel Institute of Japan; Volume: 54; Issue: 8 Linguagem: Inglês

10.2355/isijinternational.54.1876

1347-5460

Jing Liu, Guocheng Xu, Xiaopeng Gu, Guanghao Zhou, Yongkui Hao,

Ultrasonics and Acoustic Wave Propagation

In this paper, ultrasonic C-scan detection is conducted on stainless steel spot welds, and C-scan images are obtained respectively through characteristic signal analysis in time domain and frequency domain. C-scan image of frequency domain characteristics signal, which is less affected by detecting conditions, can reflect the weld nugget morphology more truly. After C-scan image enhancement and edge detection processing, the dimension of spot weld nugget can be automatically obtained through equivalent diameter algorithm procedure. The dimension of nugget contains corona bond, and it is in good agreement with corona bond external diameter through metallographic measured value. So it can be taken as the reference to evaluate the quality of spot welds. Without the influence of corona bond, detection accuracy is very high. The error is less than 0.066 mm.