Ferromanganese Grades: High, Medium and Low Carbon FeMn
Ferromanganese is commonly divided into high carbon, medium carbon and low carbon ferromanganese according to carbon content. The main difference between the three categories is the amount of carbon introduced together with manganese during alloy addition.
High carbon ferromanganese generally contains about 7–8% C and is used where the steelmaking process can accommodate a higher carbon input. Medium carbon ferromanganese reduces carbon to around 1–2%, while low carbon ferromanganese can contain less than 1% C for steel grades requiring tighter carbon control.
Carbon level also affects the production route. High carbon FeMn is mainly produced through carbothermic reduction, while medium and low carbon grades require additional refining or lower-carbon reduction processes.
For buyers, carbon classification is the starting point. The specific Mn, C, Si, P and S requirements should then be confirmed according to the required FeMn grade.
Ferromanganese Specifications and Grade Designations
A FeMn grade normally indicates the target manganese and carbon levels. For example, FeMn78C8.0 represents a ferromanganese grade with a nominal Mn level of 78% and a carbon specification of 8.0%.
Typical ferromanganese grades include:
| Category | Grade | Mn (%) | C (%) |
| High Carbon | FeMn78C8.0 | 75–82 | 8.0 |
| FeMn74C7.5 | 70–77 | 7.5 | |
| FeMn68C7.0 | 65–72 | 7.0 | |
| Medium Carbon | FeMn82C1.0 | 78–85 | 1.0 |
| FeMn82C1.5 | 78–85 | 1.5 | |
| FeMn78C2.0 | 75–82 | 2.0 | |
| Low Carbon | FeMn88C0.2 | 85–92 | 0.2 |
| FeMn84C0.4 | 80–87 | 0.4 | |
| FeMn84C0.7 | 80–87 | 0.7 |
Besides Mn and C, Si, P and S are important parts of a ferromanganese specification. The reference data shows different impurity limits for each grade, with lower P and S requirements generally specified for low carbon grades.
Particle size also needs to be agreed before shipment. Depending on the steelmaking charging system, FeMn can be supplied in different lump sizes, with packing and size tolerance specified in the purchase order.
A complete FeMn specification should cover grade, chemical composition, particle size, packing, quantity and inspection requirements.
Ferromanganese Production Process and Reduction Reactions
High carbon ferromanganese is commonly produced by carbothermic reduction in a submerged arc furnace. Manganese ore, carbonaceous reductant and fluxes are prepared and proportioned before smelting.
During heating, manganese oxides are progressively reduced:
MnO₂ → Mn₂O₃ → Mn₃O₄ → MnO
The key high-temperature reduction can be simplified as:
MnO + C → Mn + CO↑
The Boudouard reaction also contributes to the reducing atmosphere:
CO₂ + C → 2CO
Reduced manganese enters the molten Fe-Mn alloy, while gangue and flux components form slag. After tapping, the alloy is cast, cooled, crushed and screened to the required size.
For medium and low carbon ferromanganese, additional refining is required to reduce carbon while maintaining manganese recovery. Silicothermic reduction can be represented by:
2MnO + Si → 2Mn + SiO₂
The final process depends on the required Mn-C balance, impurity limits and target FeMn grade.
How to Choose a Reliable Ferromanganese Supplier
When selecting a ferromanganese supplier, buyers should first confirm the supplier’s manufacturing capability and quality-control system. Stable raw materials and controlled production are important for maintaining consistent FeMn chemistry between batches.
The supplier should provide clear COA and TDS covering Mn, C, Si, P and S. For larger orders, buyers can also request samples and third-party inspection such as SGS or BV according to the purchase requirements.
Physical specifications should be confirmed at the same time, including particle size, size tolerance, packing and loading requirements.
For long-term supply, reviewing multiple batch COAs is useful for checking chemistry consistency. A reliable supplier should also be able to maintain the agreed specification and delivery schedule across repeat shipments.
For industrial FeMn purchasing, four points deserve attention: production capability, chemical consistency, quality verification and supply reliability.