Rautaseosten

Rautaseosten (iron alloys) are metallic materials composed mainly of iron with other elements added to improve mechanical properties such as strength, hardness, ductility, or corrosion resistance. They cover a broad range of materials used in engineering, construction, and consumer goods, and their exact properties depend on composition and heat treatment.

The main families are steel and cast iron. Steel is iron with a relatively low carbon content (up to about 2%) and often contains alloying elements such as chromium, nickel, vanadium, or molybdenum to tailor strength, toughness, and wear resistance. Cast iron contains higher carbon content (typically above 2%) and silicon, which gives good castability and often excellent wear resistance but can reduce ductility. Stainless steels are a notable subclass with a minimum chromium content around 10.5%, providing corrosion resistance. Tool steels are alloyed to achieve high hardness and heat resistance for cutting and forming applications.

Production typically starts with the smelting of iron ore and refining in furnaces, followed by alloying, cast­ing, and heat treatment. Common production routes include basic oxygen steelmaking and electric arc furnace refining, with rolling, forging, or extrusion to achieve final shapes.

Key properties of iron alloys include strength, hardness, toughness, wear resistance, and machinability, all of which depend on composition and heat treatment. Applications range from structural components in buildings and bridges to automotive parts, machinery, cutlery, and industrial tools. Iron alloys have played a central role in metallurgy since antiquity, with steel development driving industrial growth. Environmental considerations focus on energy use in production and the benefits of recycling, particularly of steel, to reduce emissions and conserve resources.