Alloy Elements: Chromium

Chromium (Cr) is a silvery-gray metal known for its presence in all special tool steels and stainless steels. This alloying element plays a crucial role in enhancing wear resistance, corrosion resistance, and tempering stability. In martensitic steels, it also improves hardenability, allowing air quenching on parts with limited thickness.

Chromium is one of the most important elements in special steels thanks to its numerous functions:

• Corrosion resistance: With minimum chromium content of 13% in solid solution, steel acquires excellent corrosion resistance. This is the basis of stainless steels.
• Carbide formation: When combined with carbon, chromium forms carbides that enhance wear resistance and edge retention in tools and mechanical components.
• Mechanical strength: Each percentage point of chromium increases the tensile strength of martensitic steels by approximately 80–100 N/mm².
• Influence on physical properties: Chromium reduces the thermal and electrical conductivity of steel and slightly lowers its toughness.
• Hardenability: High-chromium martensitic steels are known as self-hardening, as they can be hardened in air. This property makes them ideal for applications requiring high hardness.