Steel is produced using iron alloys combined with carbon and additional elements such as copper, chromium, manganese, cobalt, nickel, titanium, silicon, and vanadium. The concentration of these elements must be high enough to ensure structural integrity and avoid undesired changes in the steel’s properties.
Alloying elements are critical additions to the chemical composition of steel because they directly influence its physical characteristics, including strength, brittleness, and elasticity. Each alloying element is added to improve specific properties of the steel, such as corrosion resistance, wear resistance, or ease of heat treatment. 
Every added substance uniquely affects the steel’s physicochemical and mechanical behavior. Unfortunately, not all have beneficial effects.
Classification of Steel by Alloy Content
- Low-alloy steel – element concentration below 2%
- Medium-alloy steel – element concentration below 8%
- High-alloy steel – element concentration above 8%
Depending on their use, we distinguish between tool steels, structural steels, and specialty steels. The key lies in selecting the right balance of alloying elements to ensure that all additions complement each other effectively.
Desirable Properties of Alloying Elements
One of the most commonly used alloying elements is molybdenum. It increases corrosion resistance, mechanical strength, and hardenability of steel. It also helps reduce steel’s brittleness. In acid-resistant steels, molybdenum content typically ranges from 2.5% to 7%.
Nickel also positively affects the hardening process. When dissolved in ferrite, it significantly improves impact resistance. It is a key component in acid-proof steels, enhancing both weldability and plastic deformation. Nickel in concentrations of 0.5% to 4% improves heat treatment properties, while 8% to 10% greatly enhances acid resistance.
Manganese is another useful addition – it increases impact and wear resistance while maintaining ductility.
Which Elements Improve Wear and Corrosion Resistance?
Chromium is essential for producing structural steels. It improves hardenability and mechanical strength. It is also used in heat-resistant, stainless, and tool steels. Without chromium, steel loses its corrosion resistance. The recommended chromium content is between 12% and 30%.
Copper also contributes to corrosion resistance. Although it shares similar physical properties with iron, it is significantly more resistant to oxidation and corros