Alloy elements: introduction

Special steels stand out for their ability to meet diverse mechanical, physical, and chemical demands, thanks to the addition of specific alloying elements. Beyond carbon (C), a fundamental element that, along with iron (Fe), forms the base of all steels, the intentional addition of other elements like chromium (Cr), molybdenum (Mo), vanadium (V), nickel (Ni), cobalt (Co), manganese (Mn), sulfur (S), tungsten (W), titanium (Ti), boron (B), silicon (Si), copper (Cu), aluminum (Al), and niobium (Nb) allows for improved mechanical properties and the achievement of specific, advanced characteristics.

The addition of alloying elements allows for the improvement of several fundamental mechanical properties, making special steels suitable for meeting particular requirements in fields such as the automotive, aerospace, energy, and tool industries. Among the main properties influenced by alloying elements are:

• Hardenability: The ability of a steel to achieve a martensitic structure in depth.
• Hardness and wear resistance: Crucial for tools and components under high mechanical stress.
• Toughness and ductility: Essential to prevent brittleness and ensure plastic deformation without fractures.
• Corrosion resistance: Indispensable for steels used in chemically aggressive environments.
• Hot strength: Necessary for applications involving high operating temperatures.
• Machinability: Needed to optimize processing times and procedures.
• Thermal conductivity: Useful for heat dissipation in specific applications.

Each alloy element added to steel has a unique impact on its properties:

• Chromium: Increases corrosion resistance and hardenability.
• Molybdenum: Improves hot strength.
• Vanadium: Contributes to wear resistance.
• Nickel: Promotes ductility and toughness at low temperatures.
• Cobalt: Increases compressive strength and hot strength.

The combination of alloying elements and their targeted dosing allows for the creation of special steels with tailor-made mechanical properties, meeting specific needs in technologically advanced fields. At Bonomi Acciai, as the Italian partner of Swiss Steel Group, we are committed to providing high-quality special steels, supported by rigorous controls and analyses, to ensure excellent performance in the most demanding sectors.