Application of synthetic aperture focusing technique to inspection of spot welded structure in aerospace products

The principle of synthetic aperture focusing technique（ SAFT） was introduced,spot welded samples with defects were detected,and the nugget diameter were measured with SAFT. The images by this method were compared with that of the radiographic and metallographic inspection,respectively. The results show that SAFT is very suitable for the inspection of spot welding structure in aerospace products,and it can provide reliable basis for quality evaluation of spot welding.