Abstract
Glass entrapment and rheology have a major impact on surface quality during hot extrusion of steel using flat dies. This paper outlines this relationship between glass properties, its behavior and the process conditions. It presents a glass rheological model which extends the previous work of Baque to unsteady conditions during extrusion. Then it included elements of an upper bound model for glass entrapment in single port extrusion. The integrated model which includes both glass rheology and entrapment is applied to the published results of hot extrusion. It is shown that the glass entrapment and flow model adequately explains the formation of the glass film and its breakdown.
