Is steel an alloy?

Steel is an alloy, which belongs to the category of metal materials. Unlike single alloys and mixtures, steel is a structure composed of multiple alloying elements. After overheating or cold processing smelting, according to the required material, the required alloying elements can be added to form steel.

The chemical composition of steel can vary greatly. Steel that contains only carbon is called carbon steel or ordinary steel. In actual production, steel often contains different alloying elements according to different uses, such as manganese, nickel, vanadium and so on.

Alloy is a concept, usually refers to two or more kinds of metal elements or metal as a matrix to add other non-metallic elements through alloying process (such as melting, mechanical alloying, sintering, vapor deposition, etc.) and formed with metal properties of metal materials.

However, alloys may contain only one metallic element, such as steel. Steel is a general term for iron alloys with carbon content between 0.02% and 2.00% by mass percentage.

Here, we need to note that alloys are not mixtures in the general concept, and can even be pure. For example, in single-phase metal intercompound alloys, the added alloying elements can form solid solutions, compounds, and produce endothermic or exothermic reactions, thereby changing the properties of the metal matrix.