There are four basic categories of steel according to the American Iron & Steel Institute (AISI). These four groups include Carbon steel, Alloy steel, Stainless steel, and Tool steel, all of which are classified based on their chemical compositions. You can easily remember this by using the acronym, “C-A-S-T.”
Of these 4 primary groups, steel can be further classified by varied properties, including physical, environmental, and chemical. This allows for many different grades of steel. Although all steel is made up of iron and carbon, the measurement of carbon and the particular alloys it contains is what determines the actual properties of each grade of steel.
One of the most common grades is Carbon steel. Continue reading to learn the three main categories of carbon steel.
Carbon steel can be categorized into 3 primary groups: Low, Medium, and High Carbon Steel:
❶ Low Carbon Steel
Low carbon steel is also known as “mild steel” and contains an average of 0.04% to 0.30% carbon content. As a category of carbon steel, it is the largest group. It is primarily used in the construction and building industry, and comes it a wide variety of shapes, from flat sheet to structural beam. The amount of added alloys can be altered and adjusted to make low carbon steel better suited for certain applications. For example, Drawing Quality (DQ) steel has less carbon and more aluminum, while structural beam steel has more carbon and more manganese.
❷ Medium Carbon Steel
Medium carbon steel contains an average carbon content between 0.31% and 0.60%, with an average manganese content of 0.060 percent to 1.65 percent. Compared to low carbon steel, medium carbon steel is stronger, making it well-suited for automotive parts, railway systems and parts, structural beams, and more. However, due to its strength, it is more difficult to mold, shape, cut, and weld. Heat treatment is usually needed to hardening and tempering medium carbon steel.
❸ High Carbon Steel
High carbon steel is also referred to as “carbon tool steel”, and contains an average carbon content between 0.61% and 1.50%. Similar to medium carbon steel, high carbon steel is hard to cut, mold, and weld, and requires heat treatment for hardening and tempering. Due to its properties, it is often used in the manufacturing of tools such as woodworking and cutting tools, as well as, high strength wires and more. Until recently, it was commonly used for railways.