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Classification and Role of Steels
Steel is an extremely important material in modern engineering and manufacturing, and is widely used in civil, industrial and commercial projects all over the world. With its unique combination of strength and malleability, steel is an ideal choice for a variety of applications, from construction to shipbuilding. As one of the most important engineering materials, steel is grouped into a variety of categories.
Carbon Steels
The most basic form of steel is known as carbon steel. This type of steel is made of iron and contains a small percentage of carbon, usually less than 2%. The amount of carbon in the steel determines the hardness and strength of the material. Carbon steel can be divided into two further subcategories, low carbon steel and high carbon steel. Low carbon steel contains less than 0.3 percent of carbon and is considered to be the most ductile and malleable form of steel. It is the most easily welded and machined, which makes it an ideal choice for a wide range of projects. High carbon steel contains more than 0.6 percent carbon and is extremely strong and brittle. It is a difficult material to work with and is used mainly in high-strength applications such as machine tools and swords.
Alloy Steels
Alloy steel is any steel that is alloyed with other materials such as molybdenum, nickel, chromium, vanadium, or manganese. Alloying steel increases its strength and hardness, making it an ideal choice for manufacturing components that are expected to endure extreme pressure and wear. Alloy steels are divided into two categories, low-alloy steels and high-alloy steels. Low-alloy steels contain up to 8 percent of alloying elements and are predominantly used in the automotive and construction industries. High-alloy steels contain between 8 and 40 percent of alloying elements and are used primarily in the aerospace and military industries.
Stainless Steels
Stainless steel is a type of steel that contains at least 10.5 percent chromium. The presence of chromium gives the material excellent corrosion resistance, making it an ideal choice for applications that are exposed to harsh environments such as the marine industry. Stainless steel can be further divided into two major categories, martensitic and austenitic. Martensitic stainless steel contains 12 to 14 percent chromium and is known for its high strength and hardness. It is ideal for applications that require strength and corrosion resistance such as medical implants and kitchen knives. Austenitic stainless steel contains 17 to 20 percent chromium and is one of the most corrosion resistant types of steel. It is ideal for applications that require a high level of corrosion resistance such as surgical instruments and submarine hulls.
Tool Steels
Tool steel is a type of steel that is alloyed with tungsten, molybdenum, chromium and vanadium. Tool steels are known for their high strength and hardness, which makes them an ideal choice for cutting and forming applications such as drills and saw blades. Tool steels can be divided into two subcategories, cold-work and hot-work. Cold-work tool steels are air-hardened and are used for applications that require excellent wear resistance. Hot-work tool steels are heat-treated and are primarily used in applications that require resistance to high temperatures, such as dies and extrusion tools.
Refractory Steels
Refractory steel is a type of steel that contains a high amount of chromium and other alloying elements. The presence of chromium and other alloying elements gives this type of steel excellent resistance to high temperatures, making it an ideal choice for applications that require extreme temperature resistance such as furnaces, kilns, and engine blocks. Refractory steel can also be divided into two further subcategories, stainless and nickel-based. Stainless refractory steel contains 10 to 20 percent chromium and is primarily used in applications where corrosion resistance is desired. Nickel-based refractory steel contains 40 to 45 percent chromium and is primarily used in applications where extreme heat resistance is desired.
In conclusion, steel is an extremely important material in modern engineering and manufacturing. It is divided into a variety of categories based on its composition, and these categories each have specific characteristics that make them suitable for particular projects. Carbon steel is malleable and ductile, making it an ideal choice for a variety of applications. Alloy steel is strong and hard, making it ideal for applications like machine tools and swords. Stainless steel is corrosion resistant, making it ideal for applications like surgical instruments and submarine hulls. Tool steel is hard and strong, making it ideal for applications like drills and saw blades. Refractory steel is heat resistant, making it ideal for applications like furnaces and engine blocks.
