Atsumi Ohno

Fabrication and characterization of continuously cast clad metallic buffer rods

The fabrication, characterization, and ultrasonic measurements of clad metallic ultrasonic buffer rods are presented. The core and the cladding consist of tin/lead alloy and pure tin, respectively, produced by a vertical continuous casting technique. The acoustic velocity profiles across the rod diameter are measured using a 225‐MHz line focus beam scanning acoustic microscope. A schlieren visualization system confirms the concentration of acoustic energy in the core. Spherical acoustic lenses have been fabricated at the ends of the rods. Focused and unfocused ultrasonic measurements at frequencies between 2 to 10 MHz and signals with excellent signal to noise ratios have been obtained.

Some Perspectives on Innovative Processing and Materials Development

Abstract Throughout a long and distinguished career, the research activities conducted by Professor Ravindran have been characterized by the quest to generate fundamental as well as practical knowledge through collaborative efforts involving academia and industry as a basis for development of innovative manufacturing routes and improvement in performance of existing products and processes based on near-net-shape casting technologies. In this paper, the generation, validation, and implementation of new knowledge is illustrated by the Ohno Continuous Casting process, a heated mold system that permits the production of net-shape or near-net-shape products with a high-quality surface, controlled solidification structure, and significantly enhanced properties.

Production of aluminum strip through continuous casting with a heated rotary mold.

A continuous casting technique for producing flat and thin strips of aluminum is developed. A rotating heated iron mold is used instead of a conventional cooling mold. It is essential for the successful production that the mold temperature should be maintained higher than the melting point of the aluminum, and that the solid-liquid interface should be located at the highest position of the mold. Heat extraction for the solidification of the strips was carried out at first by way of a dummy plate and then, with the solidified strip in fixed position, by use of cooling sprayed water. The strips obtained showed an unidirectionally solidified structure. The surface of the strip proved extremely smooth and flat, if a suitable position of pouring molten aluminum into the rotary mold is chosen.