Acid Open-Hearth Steel Making
Introduction
Acid open-hearth steel making is a process used to produce steel from ore in an oxygen-enriched environment. The process involves combining iron ore, flux materials, and scrap steel in a large open-hearth furnace. The heat enables the steel to be separated from the other components and smelted into an alloy with a variety of other metals. Heat treatment and annealing are usually performed to temper the steel in order for it to be used for various applications.
Process
The process of acid open-hearth steel making begins with the preparation of the raw materials. Iron ore, flux materials and scrap steel are loaded into a large open-hearth furnace that is heated to temperatures of about 2500°F. This heating process enabled the steel to be separated from the other components, which are then melted down.
The main ingredient in steel production is iron ore. The iron ore is combined with flux materials, such as limestone and dolomite, which helps to remove the non-metallic elements present in the ore. The combination of these materials is heated until it melts, which is then slag-floated to remove any remaining impurities. This molten mixture is known as “steel bath”.
Scrap steel is then added to the bath, which will act as a fuel source and also adds other elements and impurities to the steel. The steel bath is stirred with a refractory-lined ladle and then heated further to a temperature of 2800°F. At this temperature, the steel bath is turned into molten steel, which is then poured into molds to create steel billets, bars or plates.
Heat treatment and annealing
Once the steel has been cast into its desired shape, it is cooled until it solidifies and is then cut into the desired lengths. After this, the steel undergoes heat treatment in order to improve its properties. This involves heating the steel up to a temperature beyond its transformation point, holding it there and then cooling it at a controlled rate. The type of heat treatment used depends on the desired result, such as flaw detection, stress relief, hardening or tempering.
After heat treatment is completed, annealing is usually performed in order to temper the steel. This involves heating the steel up to a temperature just below its transformation point and then allowing it to cool slowly in its own furnace. The process of annealing relieves internal stresses and improves the performance of the steel.
Conclusion
Acid open-hearth steel making is an important process used to produce steel from ore in an oxygen enriched environment. The process combines iron ore, flux materials and scrap steel in a large open-hearth furnace that is heated to temperatures of about 2500°F, which then enables the steel to be separated from the other components and smelted into an alloy with other metals. Heat treatment and annealing are usually performed to adjust the properties of the steel.
