The gating system—consisting of the pouring basin, sprue, runner, and gates—must be designed to minimize velocity changes and prevent the Bernoulli effect from creating a vortex that sucks slag into the cavity. Flinn stresses the use of a and choke to control the flow rate. Furthermore, the viscosity of the molten alloy (which is inversely related to temperature) dictates how easily it navigates thin sections. Too high a viscosity (i.e., too cold a pour) leads to misruns and cold shuts; too low a viscosity (i.e., too hot a pour) increases gas solubility and shrinkage.
Flinn emphasizes that the transition from liquid to solid is the most critical phase in casting, as it dictates the final mechanical properties. Fundamentals Of Metal Casting Flinn Pdf
But seek the information legally. Use the PDF search as a starting point to locate the text in a university database, purchase a used copy, or find a modern replacement written by John Campbell (which updates Flinn’s work for the 21st century). The gating system—consisting of the pouring basin, sprue,
If your casting suffers from a misrun, Flinn would tell you to increase superheat (pour hotter) or adjust the gating system to fill from the bottom (turbulence reduction). Too high a viscosity (i