[en] To provide a diverse mean for the inspection of French PWR Cast Stainless Steel components (piping, elbows, pump bowls), EDF has undertaken a research programme to improve the performances of ultrasonic testing method of these components. We present in this paper the quantification of the capabilities of an ultrasonic procedure using optimized contact probes in order to determine the application field of this UT procedure. On a large variety of products representative of cast components, we have studied the different macrostructures that can occur, their influence on the ultrasonic propagation and the capabilities of the ultrasonic method on representative blocks that contain artificial defects. Depending upon the chemical composition, fine structures with predominantly austenitic equiaxe grains or coarse structures with only columnar grains can occur. The ultrasonic propagation is very inhomogeneous in the coarse columnar grain structures. In fine structures, ultrasonic propagation is more homogeneous, with sometimes high acoustic attenuation of background noise. Since a stable echo is preferred to a disturbed one, we consider that these materials are easier to control. We have seen that materials that are prone to thermal ageing embrittlement, which belong to fine structures, can be correctly inspected until 50 mm depth. (author). 6 figs., 9 refs