Steelmaking is the process of refining raw materials into steel by a variety of methods. One of the most common methods of steel production is the transfer of molten steel from a holding furnace to a castable refractory lining of a ladle furnace. This allows for a variety of steel grades to be accurately controlled for end use.
The process begins with a charge of molten steel from the steelmaking furnace being discharged into the ladle. The molten steel temperature will range from just below the liquidus temperature of the steel to a much higher temperature. The addition of various alloying elements to the steel also takes place in this area. These elements are added for specific purposes such as increased strength, corrosion and wear resistance, as well as other uses. The addition of these elements elevate the steel’s temperature from the holding furnace to a temperature suitable for the static pour of the steel into the molds.
Once the liquid steel is in the ladle, there are a number of steps that occur before the molten steel is poured into the molds. The first step is to ensure that the ladle is properly lined with the correct castable refractory. The refractory must be grooved, or convexed, appropriately to ensure an even, uniform flow of the steel during the cast. The most widely used refractory is known as stainless steel filled corundum, which is composed of a cobalt-nickel alloys.
As the molten steel is discharged into the ladle, it is stirred. The stirring removes oxygen from the steel and helps to reduce the presence of non-metallic inclusions that can degrade steel quality. The stirring of the molten steel continues throughout the entire process in order to achieve the desired outcome.
Once the liquid steel is at the correct temperature and the correct alloying elements have been added, the steel is ready to be poured into molds. This is most often done via the ladles static pour pipe, which contains an adjustable spout that controls the rate of pouring and the area of coverage. If a static pour is not possible, a vibratory pour can also be used.
Once the poured steel has cooled and solidified, it is removed from the mold. The steel is then inspected for quality and can be further processed, if necessary, in order to achieve the desired outcome.
The entire steelmaking process, from raw material refining to the removal of the finished product from the molds, is an extremely complex process. Careful attention must be paid to temperature, chemical composition, addition of alloying elements and the rate of pouring in order to achieve the desired steel grade and quality. With the proper equipment and expertise, however, it is possible to create a wide range of high quality steel products that meet tight tolerances.
