Five production methods of ferroalloy

Introduction

Ferrous alloys constitute a large and diverse class of materials that include iron and some or all of its primary alloying elements. This article discusses the five production methods of ferrous alloys, namely, cast iron, ferroalloy, alloy steel, stainless steels and tool steels.

Cast Iron

Cast iron is produced by chemical refining and casting in sand or molten metal molds. The first step in producing cast iron is to reduce the iron ore into raw pig iron, which is an alloy mainly composed of iron and carbon. The pig iron is then purified using oxides and alloys in a process known as oxidation. After the addition of alloying elements, the mixture is heated and poured into a two-piece sand or metal mold to produce a cast iron component.

Ferroalloys

Ferroalloys are created by combining elements like chromium, manganese, silicon, nickel, and molybdenum to iron. The elements are added to the molten iron in a controlled de-oxidation process. This process increases the performance and marketability of the product. The material produced has a higher melting point and higher corrosion resistance than plain iron, making it more suitable for industrial applications.

Alloy Steel

Alloy steel is a steel alloy component produced by adding certain alloying elements to the iron. These elements are introduced in order to obtain certain properties and characteristics of the steel. Alloying with other elements, such as aluminum, copper, nickel and titanium, can lead to improved corrosion resistance and heat resistance, as well as greater tensile strength and yield strength.

Stainless Steel

Stainless steel is produced by adding chromium to an alloy of iron and carbon. This makes the steel highly resistant to rust, which is ideal for industrial use due to its durability and chemical resistance. Depending on the application, additional elements can be added for specialized requirements.

Tool Steel

Tool steel is an alloy of iron and carbon, with added alloying elements such as molybdenum, chromium, vanadium, and tungsten. This type of steel is highly resistant to wear and tear, making it an ideal material for applications where strength and durability are needed.

Conclusion

Ferrous alloys are used in a variety of applications, from automotive components to infrastructure and building construction. The five production methods discussed in this article produce components with different levels of strength, wear resistance, and corrosion resistance. The properties of the ferrous alloy depend on the production method used, i.e., cast iron, ferroalloy, alloy steel, stainless steel, or tool steel.

The production method of ferroalloy is mainly divided into five kinds, namely melting reduction method, electric arc furnace conversion method, submerged arc furnace reduction method, molten salt method and electric thermal method.

The melting reduction method uses the liquefaction furnace as a reducing furnace to melt the iron ore in a certain proportion, adding the alloy elements and reductant. The reduction process mainly relies on physical and chemical phenomena. This method is mature and simple, and the cost is low, so it is the most widely used method of ferroalloy production.

The electric arc furnace conversion method is to put the charge (mainly iron ore, flux, alloy and reductant) into the electric arc furnace, turn on the electric current, open the arc and make the charge into molten state under the huge arc thermal action and electromagnetic stirring effect, and when the molten state reaches a certain temperature, the alloy element is added for conversion.

Submerged arc furnace reduction method is to put the charge (mainly iron ore, flux, alloy and reductant) into the submerged arc furnace, spread the electrodes in the furnace on the bottom and sidewalls, and turn on the power to make the furnace liquidate and reduce the composition at the same time. When the process is completed, the alloy element is added to the melted slag for alloying.

Molten salt method is mainly used in the production process of sodium ferroalloy, which is easier to release nitrogen and sulfur in the molten salt reaction process, and reduce the final nitrogen and sulfur content in the ferroalloy produced. In the actual production process, calcined iron ore powder is added to nitrogen-free soda water to produce sodium ferroalloy after the reaction is completed.

The electric thermal method is mainly used in the production of ferroalloy in silicon and aluminum, using the electric thermal process to reduce the metal oxide to obtain the alloy element. In actual production, the concentrated ore (the oxide of alloy element) is placed in a graphite or carbon block, and electric current is passed to reduce the oxide to form the metal.