A novel nonlinear pressurization method for counter-gravity casting of cross-sectional mutation structures

Abstract

In order to ensure the filling integrity of complex counter-gravity casting and improve metallurgical quality, it is necessary to shorten the filling time while avoiding air entrainments. To address this contradiction, a novel nonlinear pressurization method was proposed in this study. Through systematically analyzing the relationship between critical filling speed and stable filling height, a criterion for iterative calculation of nonlinear pressurization speed was established, and an empirical expression between nonlinear pressurization speed and the filling height was obtained. Based on the empirical expression, a nonlinear pressurization curve can be designed according to the casting structures and initial pressurization speeds. The above nonlinear pressure curve design method was validated through water simulation. It was proved that the nonlinear pressure curve can shorten the filling time while avoiding air entrainments. It provides important processing control method for improving the low-pressure casting performance of complex castings.