Nickel Alloy FeNi NPI-MG
Grade
NPI-MG = nPI medium grade
Transitional RKEF product; used where a moderate nickel unit with high carbon is acceptable.
Values for the NPI-MG condition
Other FeNi tempers and conditions
FeNi is listed in 9 conditions; see the grade overview at FeNi.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Ferronickel, nominal 38–42 % Ni | Top graded ferronickel (e.g. New Caledonia / Japanese smelters); highest payable, lowest impurity dilution. | 260 | 320 | 1 | 20 HRC | 2.2 % IACS |
NPI low grade | Cheapest nickel unit for 200-series stainless and low-alloy steel where high C, Si and S are tolerable. | — | 280 | 0 | 43 HRC | 3.8 % IACS |
NPI-MGThis page NPI medium grade | Transitional RKEF product; used where a moderate nickel unit with high carbon is acceptable. | — | 300 | 0.3 | 41 HRC | 3.3 % IACS |
Ferronickel, nominal 15 % Ni | Low end of the graded ferronickel range; bridges NPI and standard FeNi20+ contracts. | 300 | 420 | 1.5 | 29 HRC | 2.7 % IACS |
NPI high grade | The workhorse feed for Chinese/Indonesian 304 stainless production; carbon 1.8–2.5 % is decarburised in the AOD. | — | 320 | 0.5 | 40 HRC | 3 % IACS |
Ferronickel, nominal 20 % Ni | Standard traded ferronickel grade for stainless melt shops wanting a defined nickel unit. | 320 | 450 | 2 | 27 HRC | 2.5 % IACS |
FeNi25Default Ferronickel, nominal 25 % Ni | Default stocked ferronickel: balanced nickel unit cost, moderate impurities, suitable for most 300-series stainless charges. | 340 | 470 | 2.5 | 26 HRC | 16 W/m·K |
Ferronickel, nominal 30 % Ni | Higher nickel unit density; fewer tonnes to handle per unit Ni, lower iron dilution of the heat. | 350 | 490 | 3 | 24 HRC | 2.2 % IACS |
Ferronickel, nominal 35 % Ni | High-grade smelter product (typically refined) for premium stainless and alloy-steel charges. | 360 | 510 | 4 | 22 HRC | 2 % IACS |
What is FeNi NPI-MG?
FeNi NPI-MG is FeNi in the NPI-MG grade — transitional RKEF product; used where a moderate nickel unit with high carbon is acceptable. FeNi NPI-MG has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 63% of nickel alloy grades. Elongation at break is 0.3% and the elastic modulus is 180 GPa (26.1 Msi). FeNi NPI-MG has a density of 7.5 g/cm³ (0.271 lb/in³), lighter than 99% of nickel alloy grades. It melts at 1,200°C (2,192 °F). FeNi25 is the default condition FabDigit quotes; NPI-MG is available on request or by drawing note.
Advantages
- High electrical conductivity — 3.3 % IACS, better than 90% of nickel alloy grades
- Conducts heat well — 20 W/m·K (11.6 BTU/hr·ft·°F), better than 87% of nickel alloy grades
- Low embodied carbon — 11 kg CO₂/kg, better than 85% of nickel alloy grades
Limitations
- Limited ductility — 0.3%, worse than 100% of nickel alloy grades
- Needs corrosion protection — 13/100, worse than 100% of nickel alloy grades
- Low fracture toughness — 24 MPa·√m (21.8 ksi·√in), worse than 99% of nickel alloy grades
- Difficult to weld — 6/100, worse than 99% of nickel alloy grades
- Limited formability — 2/100, worse than 99% of nickel alloy grades
FeNi NPI-MG properties
Typical room-temperature values for FeNi NPI-MG; 25 are specific to this condition. Other listed values are FeNi reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
FeNi NPI-MG has a density of 7.5 g/cm³ (0.271 lb/in³), lighter than 99% of nickel alloy grades. It melts at 1,200°C (2,192 °F).
Mechanical16
FeNi NPI-MG has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 63% of nickel alloy grades. Elongation at break is 0.3% and the elastic modulus is 180 GPa (26.1 Msi).
Thermal5
FeNi NPI-MG is rated for continuous service to 420°C (788 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), better than 87% of nickel alloy grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
FeNi NPI-MG conducts electricity at 3.3 % IACS, better than 90% of nickel alloy grades.
Chemical & Environmental2
Corrosion resistance is not recommended (13/100), worse than 100% of nickel alloy grades.
Sustainability4
Producing a kilogram of FeNi NPI-MG takes about 125 MJ of energy and emits 11 kg of CO₂ — less than 89% of nickel alloy grades. Typical recycled content is 0%.
Manufacturability5
FeNi NPI-MG's machinability is not recommended (11/100, worse than 90% of nickel alloy grades); weldability not recommended (6/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with FeNi NPI-MG
Is FeNi easy to machine?
Not a machining stock — as-cast high-carbon ferronickel is hard and brittle; ingots are broken/crushed or supplied as shot rather than cut.
Can FeNi be welded?
Not welded; it is a charge material remelted in EAF/induction/AOD, where its carbon and sulphur must be accounted for in the refining balance.
Can FeNi be formed, bent or molded?
No wrought forming; produced by RKEF/electric-furnace smelting and cast into ingots, pigs or water-granulated shot.
What surface finishes work on FeNi?
No surface finishing; store dry and covered to limit rust and moisture pickup that would cause spitting and slag load on charging.
FeNi chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Nigraded classes run 15–40 % Ni; NPI grades 1.5–12 % | 24 – 26 | 25 |
| Coco-reported with Ni from laterite ore | 0.3 – 1.5 | 0.8 |
| C≤0.03 % in refined low-carbon grades | 0.02 – 2.5 | 1.8 |
| Si≤0.05 % after refining | 0.05 – 2.5 | 1 |
| S≤0.02 % refined; key contract penalty element | ≤ 0.35 | 0.1 |
| P≤0.02 % refined | ≤ 0.04 | 0.02 |
| Crcarried over from chromite in laterite | ≤ 2 | 0.5 |
| Cu | ≤ 0.1 | 0.02 |
| Fe | balance | — |
FeNi NPI-MG — frequently asked
What is FeNi NPI-MG used for?
FeNi NPI-MG is typically used for stainless steel melt charge addition, alloy steel nickel alloying and foundry additive. In short: lowest-cost nickel unit; steelmaking charge material only; carries carbon and sulphur.
What is the yield strength of FeNi NPI-MG?
FeNi NPI-MG has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 63% of nickel alloy grades. Strength varies by condition: see the 9 listed tempers.
Is FeNi NPI-MG easy to machine?
Not especially — machinability is rated not recommended (11/100, worse than 90% of nickel alloy grades). Not a machining stock — as-cast high-carbon ferronickel is hard and brittle; ingots are broken/crushed or supplied as shot rather than cut.
Can FeNi NPI-MG be welded?
Not readily — weldability is rated not recommended (6/100). Not welded; it is a charge material remelted in EAF/induction/AOD, where its carbon and sulphur must be accounted for in the refining balance.
What surface finishes work on FeNi NPI-MG?
No surface finishing; store dry and covered to limit rust and moisture pickup that would cause spitting and slag load on charging.
Can FeNi NPI-MG be formed, bent or molded?
No wrought forming; produced by RKEF/electric-furnace smelting and cast into ingots, pigs or water-granulated shot.
What is the maximum service temperature of FeNi NPI-MG?
FeNi NPI-MG is rated for continuous use to about 420°C (788 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between FeNi25 and FeNi40?
FeNi25 is the default condition — default stocked ferronickel: balanced nickel unit cost, moderate impurities, suitable for most 300-series stainless charges. FeNi40: top graded ferronickel (e.g. New Caledonia / Japanese smelters); highest payable, lowest impurity dilution. Yield strength is 340 MPa in FeNi25 versus 260 MPa in FeNi40.
Sources
- ASTM A550 — Standard Specification for Ferronickel — ASTM International (2019)
- ISO 6501 — Ferronickel, specification and delivery conditions — ISO (1988)
- GB/T 25049 (2010)
- ASM Handbook Vol. 2 — Properties of Fe-Ni alloys — ASM International (1990)
- Life Cycle Data for Class 1 and Class 2 Nickel (ferronickel / NPI) — Nickel Institute (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.