ULTRASONIC TESTING OF LARGE BLOCKS FOR PRESTRESS CAST IRON PRESSURE VESSELS.

Ultrasonic tests were made on plate specimen and large blocks of perlit cast iron with lamellar graphite. Aims of the investigations were the control of material properties, the flaw detection and flaw classification. The material properties were classified by sound velocity and attenuation measurements. Flaw detection and flaw size estimation methods were modified with regard to the acoustic properties, the microstructure and the reflectivity of typical flaws in castings. Special localization and flaw size estimation techniques are discussed.