| The levitation melting technique has been used to study the reoxidation behaviour of two steel alloys deoxidized with titanium and two different grades of pure iron. Chronological development of surface oxides including displacement of prior deoxidation products and formation of new oxides has been investigated.;Three different oxide morphologies were observed on levitated and solidified steel samples containing titanium. After exposure to calcium vapor the surface oxide morphology was observed to change in one of two ways; the oxide either becomes more refractory in nature, or the oxides become liquid and float on the surface of the droplet as a thin layer.;In the steels deoxidized with calcium, titania-rich deoxidation inclusions appear to be porous and non-wetting when in contact with the liquid droplets. Capillarity, and in particular surface tension forces are important in the formation of metallic "beads" on oxide inclusion surfaces. Three possible models for the formation of the metallic "beads" are presented.;For the two different grades of pure iron, calcium vapor additions significantly lowered the apparent surface tension. For one grade steel deoxidized with titanium that was studied, the calcium vapor addition again significantly lowered the apparent surface tension.;The thermodynamic data of the Fe-O-Ca-Ti system have been reviewed and extended in order to determine the feasibility of production of liquid CaTiO... |
