Ultrasonic Treatment of the 304 Stainless Steel Melt

Ultrasonic treatment of the melt metals is a hot research topic; however, it is hard to introduce ultrasound into liquid steel because of the requirement of resistance to high temperature and erosion in the melt. In this paper, the author proposed a new method to introduce ultrasound into liquid steel. The metal to be treated is cast together to the tip of the booster. During the test, the booster is placed upward with the metal to be treated connected on the top as a free end, which is melt by induction coils. The booster which generates ultrasound, by this way, acts on the melt pool. The determination of the length of the booster under this situation is given. The effect of ultrasonic treatment on the melt of 304 stainless steel is studied. The microstructure of the treated area is significantly refined and equi-axed grains are obtained; the fragmentation of inclusions occurs due to the ultrasonic treatment; the mechanism of the fragmentation of the dendrite and inclusions is discussed.