Manganese (Mn)
Manganese is the fourth most-used metal globally, essential for steelmaking where it serves as a deoxidizer, desulfurizer, and strengthening element. Approximately 90% of manganese production goes into steel. It is also growing rapidly in battery applications as a cobalt alternative and is critical for Hadfield wear-resistant steel.
Properties
- Density
- 7,210 kg/m³
- Melting Point
- 1,246 °C
- Boiling Point
- 2,061 °C
- Thermal Conductivity
- 7.81 W/(m·K)
- Electrical Resistivity
- 1.44 × 10⁻⁶ Ω·m
- Tensile Strength
- 480–690 MPa
- Yield Strength
- 240–345 MPa
- Hardness
- 196 HB (pure)
- Elongation
- 1–2% (pure)
- Crystal Structure
- BCC (α)
Common Grades
- FeMn HC (65–78% Mn): High-carbon ferromanganese. Primary steelmaking additive for deoxidation and alloying.
- SiMn (65–68% Mn): Silicomanganese. Combined deoxidizer and alloying addition for steel production.
- EMM (99.7% Mn): Electrolytic manganese metal. High-purity applications, specialty alloys, batteries.
- Hadfield Steel (11–14% Mn): Austenitic manganese steel. Work-hardens under impact — crushers, rail crossings, excavator teeth.
Applications
- Steelmaking: Deoxidizer, desulfurizer, and alloying element in virtually all steel grades
- Wear Parts: Hadfield manganese steel for crusher jaws, cone liners, rail crossings, dredger components
- Batteries: LMO and NMC lithium-ion cathodes, alkaline battery cathodes (MnO₂)
- Aluminum Alloys: 3xxx series aluminum alloy strengthening (e.g., 3003 for beverage cans)
FAQ
What is Hadfield manganese steel?
Hadfield steel (X120Mn12) contains 11–14% manganese and 1.0–1.4% carbon. In its solution-annealed condition it is tough and relatively soft (~200 HB). Under impact or compressive loading, the surface work-hardens to 500+ HB while the core remains tough — ideal for crusher liners, railroad crossings, and excavator teeth.
Why is manganese essential for steel production?
Manganese serves three critical functions: (1) deoxidation — removes dissolved oxygen that causes porosity, (2) desulfurization — combines with sulfur to form MnS inclusions instead of brittle FeS at grain boundaries, (3) strengthening — increases hardenability and tensile strength. Typically 0.3–1.5% Mn in structural steels.
What is silicomanganese and how is it used?
Silicomanganese (SiMn) is a ferroalloy containing 65–68% Mn and 15–20% Si. It provides both deoxidation (silicon) and manganese alloying in a single addition to molten steel, reducing cost and improving efficiency. Over 30% of manganese is consumed as SiMn rather than ferromanganese, especially in flat and long product steelmaking.