Hydrogen and Nitrogen Gas Content in Steel Melted by Electric Arc Furnace and Submerged Arc Furnace
Steel melting is one of the core technologies of the steel industry. Different steel melting furnaces have different characteristics and properties, making them suitable for different applications. The two most common types of steel melting furnaces used in the industry are the electric arc furnace (EAF) and the submerged arc furnace (SAF). In these types of furnaces, the amount of nitrogen and hydrogen in the molten steel can vary significantly, depending on the furnace and the type of steel being melted. This article examines the general nitrogen and hydrogen gas content in steel melted in EAF and SAF.
In an EAF, the melting process occurs when an electric arc is struck between carbon electrodes and a steel scrap mixture. This results in a bath of molten steel and slag, which is tapped from the furnace and cooled. Generally, the lower the voltage applied to the electrodes, the lower the temperature of the molten steel and thus, the lower the amount of nitrogen and hydrogen in the steel.
In an SAF, an arc is created between graphite and carbon electrodes, which are submerged in a bath of molten steel and slag. The electrodes are heated and current is passed through them, which is then transferred to the molten steel bath below. This process results in a more homogenous mix of steel and slag, compared to the EAF, which leads to a lower level of nitrogen and hydrogen in the steel.
The amount of nitrogen and hydrogen gas contained in steel melted in EAF or SAF depends on many factors, including the raw material composition and the type of steel being melted. In general, EAF steel contains a higher amount of nitrogen and hydrogen gas than SAF steel, as the higher temperatures and less homogenous mix of raw material mean the nitrogen and hydrogen have a greater chance of escaping into the atmosphere during the steel melting process.
To reduce the amount of nitrogen and hydrogen in steel melted in EAF and SAF, manufacturers employ various techniques, such as changing the type of raw material used to melt the steel, or adding special inert gases to the furnace. The aim of these measures is to minimize the amount of nitrogen and hydrogen gas in the steel by making the steel melting process more efficient.
In summary, the amount of nitrogen and hydrogen gas in steel melted in EAF and SAF depends on the type and composition of the raw material used and the type of steel being melted. Generally speaking, steel melted in EAF contains a higher amount of nitrogen and hydrogen gas than the steel melted in SAF. To reduce the amount of nitrogen and hydrogen in steel, manufacturers employ various measures, such as changing the type of raw material used or adding special gases to the furnace.
