Carbon steels are the most commonly used construction materials for making cars, ships, bridges, and transportation buildings. They are available in a wide range of sizes and shapes for a variety of applications.
Carbon steel is composed of iron, carbon, and other elements, with the main element being iron, and the small amounts of other elements making up the remaining small amounts of the metal. Carbon steels range from ultra-high strength steels with low carbon content to relatively soft steels with a higher carbon content. The microstructure of the metal is also affected by the types and amounts of other elements added to the metal, such as manganese, chromium, and nickel.
Carbon steels are classified into four general categories depending on their chemical composition and the amount of carbon they contain: low-carbon steels, medium-carbon steels, high-carbon steels, and ultra-high-carbon steels. Low-carbon steels have less than 0.3% carbon, while medium-carbon steels have 0.3-0.6% carbon, and high-carbon steels have 0.6-1.4% carbon. Ultra-high-carbon steels have more than 1.4% carbon. The higher the carbon content, the higher the steel’s strength and hardness.
Low-carbon steels are very soft and ductile and are easily workable. Due to their low hardness, low-carbon steels are not suitable for high-strengthen applications but are used for making parts requiring good formability. Examples of low-carbon steels include AISI 1010, 1020 and 1030 steels.
Medium-carbon steels, also called mild steels, have between 0.3-0.6% carbon. These steels are stronger than low-carbon steels but are still malleable and not quenched. Examples of this type of steel include AISI 1040, 1045, and 1050 steels.
High-carbon steels have between 0.6-1.4% carbon and tend to be very hard and strong. These steels are tempered and quenched after the machining process to strengthen them further. Because of their high hardness and strength, high-carbon steels are commonly used for making springs, files and cutting tools. Examples of high-carbon steels include AISI 1060, 1080 and 1095 steels.
Ultra-high-carbon steels have more than 1.4% carbon, making them very hard but relatively brittle. These steels are not quenched and are not used for general applications but are instead used for making swords, axes and other cutting tools. Examples of ultra-high-carbon steels include AISI 1095 and 1098 steels.
In addition to the four general categories of carbon steels, there are also other specialized types of carbon steel with unusual chemical compositions. These are commonly used for specific applications and examples include maraging steels and tool steels.
Carbon steels have become the preferred choice in many engineering applications due to their low cost, availability and ability to be machined and shaped. They are an important part of the industrial production process and are used for making a wide range of products from cars and ships to steel girders and bridges.
