[en] Ultrasonics has become one of the important tools for non-destructive characterisation of processed materials viz. metals, alloys, ceramics, composites and plastics. Ultrasonic velocity and attenuation in material are related to the properties of the material. Any variation in these two characteristics can be related to the material properties. This paper discusses the application of ultrasonics in property evaluation, especially in nuclear and steel industries. Experiments were carried out on nuclear fuel pellets for determining the sintered density using longitudinal ultrasonic velocity. Application of ultrasonics in non-destructive characterisation of steels is also briefly mentioned in this paper. (author)