The process of steelmaking is generally pig iron brain carbon process, basically high-temperature iron into the converter blowing oxygen, add the appropriate amount of alloy, and then vacuum and other refining furnace for refining, to get the required steel. There is also an electric furnace steelmaking, followed by the same procedure.
Steel, or iron and steel, is an alloy made by combining iron with other elements, the most common of which is carbon. Carbon makes up about 0.02% to 2.0% of the weight of steel, depending on the grade of steel. Other alloying elements sometimes used include manganese, chromium, vanadium and tungsten.
Carbon, along with the other elements, acts as a hardening agent, preventing dislocations from occurring in the lattice of iron atoms as atoms slip past other atoms. By adjusting the amount of alloying elements and the form in which they are present in the steel (solute elements and participating phases), it is possible to control the properties of the finished steel, such as hardness, ductility and strength. Carbonized steel will be harder and stronger than pure iron, but it will be less ductile than iron.
Alloys containing more than 2.0% carbon are called cast iron because they have a lower melting point and are more castable. Steel is also different from cooked iron, which can contain small amounts of carbon, but these carbon impurities are residual slag trapped in the steel. Two properties of steel that distinguish it from cast iron and pig iron are its higher resistance to rust and its better weldability.
While people had known how to produce steel using a variety of inefficient methods long before the Renaissance, it was not until the seventeenth century that steel became commonplace, when more efficient production methods became available. Since the invention of Bessemer steelmaking in the nineteenth century, steel has been a cheap material that can be produced in large quantities.
The steelmaking method was later improved, for example by alkaline-oxygen steelmaking, which made steel cheaper to produce, but at the same time of better quality. To this day, steel is a common material in the world, with an annual production of 1.3 billion tons. Steel is a major component in all kinds of buildings, infrastructure, tools, ships, automobiles, machinery, appliances and weapons. Modern steel is generally distinguished by different quality standards set by various standardization groups.
Expanded Information
All natural iron in the Earth's crust is in the form of ores, generally iron oxide, such as magnetite and hematite. To extract the iron, the oxygen in the iron ore is removed, allowing the oxygen to combine with other chemical elements, such as carbon.
This process, called smelting, was first applied to metals with low melting points, such as tin, which has a melting point of about 250 °C, and copper, which melts at about 1,100 °C. Cast iron, on the other hand, has a melting point of about 1,100 °C. It has a melting point of about 1,100 °C, and is used to extract iron. Cast iron, on the other hand, has a melting point of 1,375 °C. This temperature was already available in bronze. Such temperatures can be reached by ancient methods that were already available in the Bronze Age.
Since the oxidation rate increases dramatically above 800 °C, it is important to keep the smelting environment low in oxygen. Unlike copper and tin, liquid iron can easily dissolve carbon. The resulting alloy (pig iron) is too high in carbon to be called steel. Subsequent steps get rid of the excess carbon and oxygen.
Many times other materials are added to the iron/carbon compound to achieve the desired properties. Adding nickel and manganese to steel increases its strength and stabilizes the austenite chemistry, adding chromium increases the hardness and melting point, and adding vanadium increases the hardness but reduces the effects of metal fatigue.
To prevent corrosion, a minimum of 11% chromium is added, which creates a hard oxide layer on the surface; this alloy is called stainless steel. Tungsten interferes with the production of carburization, allowing martensite to be produced at a lower quenching rate; this finished product is called high-speed steel. On the other hand, sulfur, nitrogen and phosphorus make steel weaker, so these ubiquitous elements must be removed from the ore.
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