Steel is classified into four main types based on its chemical composition: carbon steel, alloy steel, stainless steel, and tool steel. All steel is made from iron and carbon, but varying carbon content and added alloys give each type distinct properties.
Carbon steel, making up about 90% of steel production, is categorized by carbon content into low, medium, and high carbon steels. Alloy steel includes additional elements like manganese and nickel to enhance strength, corrosion resistance, and other properties, making it ideal for uses like pipelines and auto parts. Stainless steel contains at least 10–20% chromium for corrosion resistance and comes in three main types: austenitic (non-magnetic), ferritic (magnetic, not heat-treatable), and martensitic (magnetic and heat-treatable). Tool steel is engineered for high durability and heat resistance, suitable for cutting and drilling tools.
Steel can also be categorized by shape—flat products (e.g. sheets, plates) and long/tubular products (e.g. rods, pipes)—and by various other factors such as production methods, finishing, heat treatment, microstructure, and strength standards. These classifications help determine the steel’s application across industries like construction, automotive, packaging, and energy.

