Low-carbon Steel 

Low-carbon steel, commonly known as mild steel, is by far the most common type of steel. Because of its low cost and material properties, low-carbon steel is suitable for a wide range of applications. Low-carbon steel contains approximately 0.05-0.25% carbon, making it malleable and ductile. Mild steel has a low tensile strength, but it is inexpensive and straightforward to form; carburizing can increase surface hardness.

High-strength, low-alloy steels (HSLA) are also categorized as low-carbon steels, with other ingredients including copper, nickel, vanadium, and molybdenum. Together, these can account for up to 10% of the steel composition. As the name implies, high-strength, low-alloy steels have higher strengths due to heat treatment. They also retain ductility, allowing them to be readily formed and machined. HSLA is more corrosion-resistant than regular low-carbon steel.

Medium-carbon Steel

Medium-carbon steel has 0.30 – 0.50% carbon and 0.60 – 1.65% manganese. This steel’s mechanical properties can be enhanced by a heat treatment involving austenitizing, followed by quenching and tempering, giving them a martensitic microstructure.

Heat treatment is only possible on extremely thin portions. However, steel can add additional alloying elements such as chromium, molybdenum, and nickel to increase its capacity to be heat treated and thus hardened.

Hardened medium-carbon steels have greater strength than low-carbon steels but at the sacrifice of ductility and toughness. This steel is mostly used in manufacturing machine components like shafts, axles, gears, crankshafts, couplings, and forgings. Still, it may also be used in rails and railway wheels.

High-carbon Steel

High-carbon steel has 0.60– 1.00% carbon and 0.30 – 0.90% manganese. It possesses the greatest hardness and toughness of carbon steel but the least ductility. Because they are nearly always hardened and tempered, high-carbon steels are extremely wear-resistant. High carbon steels might be employed in springs, rope wires, hammers, screwdrivers, and wrenches.

Tool steels and die steels are high-carbon steels containing extra alloying elements such as chromium, vanadium, molybdenum, and tungsten. The incorporation of these elements leads to particularly tough wear-resistant steel, which is a consequence of the production of carbide compounds like tungsten carbide (WC).

Properties And Applications of Common Carbon Steel Grades

Carbon steel comes in various forms, and can be used in many industries and sectors. Low-carbon steels are frequently used in vehicle body components, structural forms (I-beams, channel and angle iron), pipelines, building and bridge components, and food cans. Medium-carbon steels are frequently used for railway tracks, train wheels, crankshafts, and gears and machinery parts needing this combination of qualities because of their high strength, resistance to wear, and toughness. High-carbon steels are utilized in cutting tools, springs, great-strength wire, and dies due to their high wear resistance and hardness.

Low-carbon, medium-carbon, and high-carbon steel correspond to some common grades. The following table compares several carbon steel grades’ examples, qualities, and applications.