Screw Systems for Supplying Slag-Forming Mixture to the Molds of Continuous-Casting Machines

摘要

The prospects for dosed supply of slag-forming mixture to the molds of continuous-casting machines are considered, and the need for further improvement of such systems is established-in particular, the use of a screw supply system. The parameters of flexible screws with internal diameter 15, 20, and 25 mm for transporting fine-grain materials are studied experimentally; these screws are based on a steel helix (external diameter 11, 16, and 18 mm; screw pitch 5, 10, 15, and 20 mm) rotating at 250-500 rpm. The output of the screw depends linearly on its speed of rotation, for the given geometric parameters. The ratio of the pitch S_s to its external diameter d_(ex) has considerable influence on screw performance. The dependence of the supply per screw turn on S_s/d_(ex) is nonlinear, with a maximum at S_s/d_(ex)= 0.9-1.1. The minimum unit energy of the screw system is observed at S_s/d_(ex) - 0.5-0.6. These results are used in the design of a new series of systems for dosed delivery of slag-forming mixture to the molds of continuous-casting machines with different cross sections.