Steel is an alloy of iron. Almost 90% of steel manufactured all over the world is carbon steel, i.e., an alloy of iron and carbon, with a varying percentage of carbon (0.2 to 2.1% by weight). Pure iron is very soft and corrosive and cannot be used in an active environment, where iron can chemically react to form oxides or sulfides. Addition of carbon solves this problem by making steel less reactive, and thus preventing it from oxidation, while preserving the desirable qualities of iron. Melting point is defined as the temperature at which the state of any matter changes from solid to liquid. For example, the melting point of ice is 0°C or 32°F, when it changes its state from solid ice to liquid water. Knowing the steel alloy’s melting point is important for its fabrication into a utile form.
Melting Point of Steel
The temperature at which steel melts depends on its type. Most types of this alloy have traces of other elements (including metals) added to it to improve its corrosion resistance, ease of fabrication, and strength. Their melting point depends on the percentage of other elements in them. Generally, steel’s melting point is around 1370°C (2500°F). Let us understand more about the types of steel alloys and their respective melting points. There are five main types of steel:
- Carbon Steel:
Steel with 0.05 to 0.15% of carbon content by weight is called mild or low carbon steel. It is also known as plain carbon steel. Apart from carbon, it also contains traces of copper (0.6%), manganese (1.65%), and silicon (0.6%). The melting point of low carbon steel is 1410°C (2570°F). This type is further classified into medium carbon steel, high carbon steel, and ultra-high carbon steel with melting temperatures ranging from 1425-1540°C (2600-2800°F). Steel with a 0.3 to 1.7% of carbon content is called high carbon steel.
- Stainless Steel:
This is the most popular steel alloy, which is used mostly for making kitchen cutlery. It is also known as inox steel, or simply inox, and is alloyed with 10.5% to 11% chromium by weight. There are five types of stainless steel, viz., austenitic, ferritic, martensitic, precipitation-hardening martensitic, and duplex stainless steel. The melting point of stainless steel is 1510°C (2750°F).
- Maraging Steel:
This type is mainly a low carbon-iron alloy, having nickel as its main alloying element (15 to 25% by weight). Its melting point is 1413°C (2575°F). This is mostly used in making bicycle frames, fencing sword blades, and golf club heads.
- Alloy Steel:
Steel, alloyed with a number of elements between 1 and 50% by weight is called alloy steel. These are of two groups, viz., low alloy steels and high alloy steels, the former being the more commonly used of the two. Low alloy steel’s melting point is 1432°C (2610°F) and that of high alloy steel is 1415°C (2600°F).
- Tool Steel:
As the name suggests, this type is mainly used for making tools, as it is the hardest variety of steel. It is a harder version of carbon and alloy steels, having a carbon percentage ranging from 0.7 to 1.4%. Manganese, chrome, nickel, tungsten, molybdenum, phosphorous, and sulfur are some of the elements added in various proportions to make other types of tool steel. The melting point of this type varies in the range 1400 to 1425°C (2550 to 2600°F).
The importance of steel is known to one and all. One major merit of steel is its ease of recycling without losing the physical properties in the process.