On Gas Contents in Molten Slag

Influence of water-vapor pressure in air on gas contents in molten steel-I

Abstract

When behaviors of gases in molten steel on steelmaking practice is studied, the knowledge of molten slag has an important role.Based on this information, in this paper the author studied the variations of hydrogen content and the total iron oxide content in molten slag with different water-vapor pressures in air.
Then, as hydrogen content in molten slag could be determined by vacuum-fusion method which consisted in heating the sample at 1450-1500°C in a Mo crucible, the author firstly experimented the relations of gas contents in synthetic slag and the water-vapor pressure in atmosphere in equilibrium state, and led the following conclusions on both slag of basic highfrequency heat and slag of basic electric heat.
1) Hydrogen content in slag just before tap is proportional to the square root of the water-vapor pressure in air, but not to the hydrogen pressure in air.
2) Hydrogen content in slag is increased with rising CaO/SiO₂ ratio in slag, and its increasz ratio becomes gradually larger when the water-vapor pressure in air is higher.
3) Hydrogen content in slag becomes gradually smaller when bath temperature is higher.
4) Total iron oxide content in slag just before tap is proportional to the water-vapor pressure in air, and is not influenced by the composition of slag and by the bath temperature.