Continuous Steelmaking
Continuous steelmaking is a process of converting raw materials including iron ore into steel products without interruption. The process is performed in an integrated steel mill which combines both melting and refining processes and is designed to produce steel products such as slabs, blooms and billets. Continuous steelmaking usually takes up to five days to complete, making it one of the longer processes for producing steel.
The first step of the continuous steelmaking process is the production of raw iron ore. This raw iron ore is melted down in the melter and then submitted to a process of refining where nonmetallic impurities are removed. One important element of refining is oxidation, which requires heated air to be blown over the molten iron in order to oxygenate it and to reduce the carbon concentration.
The second step of the continuous steelmaking process is the primary steelmaking stage. This stage involves the addition of alloying elements such as manganese and chromium to the steel in order to achieve desired characteristics in the final product. The steel is then cleaned and ladled into a furnace. The furnace is then subjected to high temperatures and oxygen is added in order to allow the oxidation of excess carbon. This process of oxidation is referred to as degassing.
The third step of the continuous steelmaking process is the secondary steelmaking stage. This stage focuses on more refined alloy additions to the steel, as well as sulfur and phosphorus control. The steel is then poured into continuous casters, which can produce slabs, blooms or billets.
The fourth step of the continuous steelmaking process is the finishing process. In this step, the steel is reheated and rolled or shaped. This process ensures the desired shape and size of the steel products.
Continuous steelmaking is a time consuming and costly process because of the high energy requirements for the melting, refining and steelmaking stages. Despite these issues, continuous steelmaking results in higher energy efficiency and greater levels of product uniformity and quality compared to other steelmaking processes. Therefore, it is one of the predominant processes used in the production of steel.
