High-frequency ultrasonic porosity testing of non-ferrous metal die-casting components

With the described measurements and theoretical estimations we have shown that ultrasonic backscattering is well suited to detect porosity and single pores in the near-surface range (0.5 to 2 mm depth) in die-casting components of complicated shape. For the range directly below the surface down to a depth of 0.5 mm the technique discussed here has to be further developed, for example by using oblique sound incidence with seperate transmitting and receiving transducers to avoid that scattering signals from pores are masked by the entrance echo. Furthermore scattering at the surface roughness has then to be taken into account.