Comparison of NDT-methods for automatic inspection of weld defects

The purpose of this study is to investigate different NDT–methods for weld inspection in an objective manner. Test objects are produced with known variation of flaws: internal pores, surface and internal cracks, toe radius and weld depth. The NDT–methods compared are: phased array ultrasound, radiography, eddy current, thermography and shearography. The results show that radiography is the better method for volumetric defects in thin plates while ultrasound is better for flat defects and thicker, non–flat plates. The thermography was shown to have good surface defect detection abilities. A combination of ultrasound and thermography results in a detection of all the non–geometrical defects is investigated in this study.