Steel: Composition, Types, and Applications

What is Steel?

Steel is an alloy, a combination of iron and carbon (ranging from approximately 0.05% to less than 2%). Specific alloying elements such as chromium (Cr) or nickel (Ni) are sometimes added for particular purposes.

Because steel is primarily refined iron (over 98%), its manufacture begins with the reduction of iron ore to produce pig iron, which is then processed into steel.

Steel Classification

Carbon Steel

Over 90% of all steels are carbon steels. These steels contain varying amounts of carbon, typically less than 1.65% manganese, 0.60% silicon, and 0.60% copper. Carbon steel is used in a wide range of products, including machine parts, car bodies, steel building structures, ship hulls, bed frames, and cutlery.

Alloy Steel

Alloy steels contain vanadium, molybdenum, and other elements in addition to larger amounts of manganese, silicon, and copper than standard carbon steel. These steels can be further classified:

Structural Steels

Structural steels are used for various machine parts such as gears, axles, and levers. They are also used in building structures, auto chassis construction, bridges, and boats. The alloy content typically ranges from 0.25% to 6%.

Tool Steels

Tool steels are high-quality steels used in cutting and shaping tools for metals and non-metals. They are used to manufacture tools such as drills, reamers, and taps.

Special Alloy Steels and Stainless Steels

Special alloy steels and stainless steels generally contain a chromium content exceeding 12%. These steels exhibit great hardness and high resistance to high temperatures and corrosion, making them suitable for use in steam turbines, gears, shafts, and bearings.

Low Alloy Steel

Low alloy steels are a more recent development. They are more economical than conventional alloy steels because they contain smaller amounts of expensive alloying elements. However, with special treatments, they can achieve greater strength and resistance than carbon steel.

Stainless Steel

Stainless steels contain chromium, nickel, and other alloying elements, which provide excellent resistance to rust and oxidation, even when exposed to moisture, acids, and corrosive gases.

Flexible pipelines for low, medium, high, and extreme pressure applications. Adapters made of bronze and stainless steel. Hydraulic hoses and industrial all-purpose suction and discharge hoses, retractable hoses. Valves, gauges, belts, clamps. Quick connectors.

Steel Bars for Construction

Steel bars are used in construction, available in smooth and grooved varieties.