Research on improving central defects of billet by external vibration strike

Abstract

Make use of the positive thixotropic characteristic which decrease wall viscous force and increasing fluidity of molten steel in mushy zone by sustained shear force acting on mushy zone. In the test, the billet surface is continuously struck by 20 Hz frequency external force at the position of 20–30% linear proportion of liquid core. The results show that with vibration strike, the central porosity is obviously reduced and shrinkage cavity has been eliminated almost totally, the central carbon segregation didn’t solve. In-situ analysis shows that the uniformity of carbon content distribution in the centre of vibration strike billet is better than that of non- vibration strike billet, and the central density of vibration strike billet is higher than that of non-vibration strike billet.