Steelmaking:
Essentially, the molten iron (pig iron) is heated and different elements are added, and the carbon content of the iron is reduced to 0.2-1.7 by means such as blowing oxygen. % of the smelting process. A variety of different textures of steel can be produced. If you add manganese, you can make manganese steel; if you add nickel, chromium, and titanium, you can make steel that is not easy to rust.
The feeding system inputs sinter (sintered in the sintering plant), coke, limestone and other raw materials into the distribution system on the top of the blast furnace, and the distribution system evenly distributes them into the furnace in a certain proportion. The hot air system blows air into the blast furnace, and the coke burns to form a certain high-temperature (1150--1200 degrees) chemical atmosphere. The iron oxides in the sinter undergo reduction reactions under this temperature and environment.
Part of the oxygen in the ore forms carbon dioxide, and part becomes carbon monoxide. Some impurity gases are discharged at high temperatures and enter the dust removal purification system and blast furnace gas recovery system. The useless carbon dioxide is discharged and the carbon monoxide is recovered. Reuse. The iron in the ore is reduced and turns into liquid molten iron at high temperatures.
Molten iron is also called pig iron. Pig iron can be divided into three categories: one is steel for steelmaking (silicon SI content is less than 1.25%); one is cast iron for casting parts and tools (silicon content is greater than 1.25%); and the other is ferroalloys (silicon content is greater than 1.25%) Mainly ferromanganese and ferrosilicon).
Extended information
Iron-carbon alloys are divided into two categories: steel and pig iron. Steel is an iron-carbon alloy with a carbon content of 0.03% to 2%. Carbon steel is the most commonly used ordinary steel. It is convenient to smelt, easy to process, low in price, and can meet the usage requirements in most cases, so it is widely used. According to different carbon content, carbon steel is divided into low carbon steel, medium carbon steel and high carbon steel. As the carbon content increases, the hardness of carbon steel increases and the toughness decreases.
Alloy steel is also called special steel. One or more alloying elements are added to carbon steel to change the structure and properties of the steel, thereby giving it some special properties, such as high hardness, high Wear resistance, high toughness, corrosion resistance, etc. Alloying elements often added to steel include Si, W, Mn, Cr, Ni, Mo, V, Ti, etc.
Alloy steel is quite rich in resources. In addition to insufficient Cr and Co and low Mn grade, the reserves of W, Mo, V, Ti and rare earth metals are very high. At the beginning of the 21st century, the proportion of alloy steel in total steel production will increase significantly.
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