Hans-Peter Heller

Selecting optimal slag conditions in the blast furnace

In selecting the best chemical composition of slag melts, it is expedient to take account of their viscosity and electrical conductivity, which are structure-sensitive properties. The viscosity and electrical conductivity of blast-furnace slag are studied experimentally. To permit correct selection of the slag conditions in the blast furnace, a parameter is proposed for assessing the relation between the structural particles of the melt: the heterogenization temperature, which takes account of the viscosity and electrical conductivity of the slag melts. The discharge temperature of the slag from blast furnace 8 at PJSC ArcelorMittal Kryvyi Rih is measured. Comparison of the actual discharge temperature of the slag and the calculated heterogenization temperature for blast furnace 8 permits identification of the optimal slag basicity (CaO/SiO2).

High Temperature Investigation of Viscosity for FeCrMnNi As‐Cast Trip/Twip Steel

The viscosity of Fe-Cr-Mn-Ni TRIP/TWIP (Transformation Induced Plasticity, Twinning Induced Plasticity) steel with varied nickel content is investigated using a vibrating finger viscometer. The viscosity of the melt is calculated from the change in power input in the field coil by an immersed finger into the liquid steel to maintain a constant peak-to-peak amplitude of the sine wave of oscillator compared to the idle state. Nickel content in steel is varied from 3 wt% to 9 wt%. The dynamic viscosity (ŋ) at 1600 °C for 3 wt% Ni is 3.73±0.14 mPas, for 6 wt% Ni 3.50±0.03 mPas, and for 9 wt% Ni 3.93±0.09 mPas. There is a kink from low to high nickel content in viscosity values of Fe-Cr-Mn-Ni alloys. This phenomenon can be explained by a change in coordination number in the melt, as reported for Fe-Ni binary system in literature. The availability of viscosity data delivers relevant input to model free fall atomization processes of FeCrMnNi alloys.