Steel Ferrium M54 HT-NIT
Finish state
HT-NIT = hT + gas nitrided
Choose when high surface hardness/wear or contact fatigue resistance is needed on an aged M54 part; core properties unchanged.
Values for the HT-NIT condition
Other Ferrium M54 tempers and conditions
Ferrium M54 is listed in 4 conditions; see the grade overview at Ferrium M54.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed / overaged | As-supplied softened bar/billet for rough machining and forming before final hardening. | 950 | 1,200 | 18 | 38 HRC | 2.9 % IACS |
Solution treated (~1060 °C) + quenched + deep frozen, untempered | Intermediate as-quenched martensitic state; not a service condition — must be aged. | 1,200 | 1,650 | 8 | 50 HRC | 2.5 % IACS |
HTDefault Austenitized, quenched, deep frozen (−73 °C) and aged ~516 °C / 10 h | Standard fully hardened aerospace condition — pick for landing gear, hook shanks, shafts and actuators needing 2000 MPa with high K_IC. | 1,725 | 2,020 | 12 | 55 HRC | — |
HT-NITThis page HT + gas nitrided | Choose when high surface hardness/wear or contact fatigue resistance is needed on an aged M54 part; core properties unchanged. | 1,725 | 2,020 | 10 | 55 HRC | 2.7 % IACS |
What is Ferrium M54 HT-NIT?
Ferrium M54 HT-NIT is Ferrium M54 supplied in the HT-NIT condition — choose when high surface hardness/wear or contact fatigue resistance is needed on an aged M54 part; core properties unchanged. Ferrium M54 HT-NIT has a yield strength of 1,725 MPa (250 ksi) and a tensile strength of 2,020 MPa (293 ksi) — stronger than 99% of steel grades. Elongation at break is 10% and the elastic modulus is 200 GPa (29 Msi). Ferrium M54 HT-NIT has a density of 7.94 g/cm³ (0.287 lb/in³), heavier than 94% of steel grades. HT is the default condition FabDigit quotes; HT-NIT is available on request or by drawing note.
Advantages
- High strength — 1,725 MPa (250 ksi), better than 99% of steel grades
- Good corrosion resistance — 25/100, better than 92% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to machine — 8/100, worse than 100% of steel grades
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 3/100, worse than 99% of steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 97% of steel grades
- Poor heat conductor — 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades
Ferrium M54 HT-NIT properties
Typical room-temperature values for Ferrium M54 HT-NIT; 21 are specific to this condition. Other listed values are Ferrium M54 reference data and may not represent this condition. Bars are the position among steel grades.
Physical1
Ferrium M54 HT-NIT has a density of 7.94 g/cm³ (0.287 lb/in³), heavier than 94% of steel grades.
Mechanical14
Ferrium M54 HT-NIT has a yield strength of 1,725 MPa (250 ksi) and a tensile strength of 2,020 MPa (293 ksi) — stronger than 99% of steel grades. Elongation at break is 10% and the elastic modulus is 200 GPa (29 Msi).
Thermal5
Ferrium M54 HT-NIT is rated for continuous service to 400°C (752 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical2
Ferrium M54 HT-NIT has an electrical resistivity of 6.5×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability3
Producing a kilogram of Ferrium M54 HT-NIT takes about 75 MJ of energy and emits 5.5 kg of CO₂ — more than 97% of steel grades. Typical recycled content is 15%.
Manufacturability6
Ferrium M54 HT-NIT's machinability is not recommended (8/100, worse than 100% of steel grades); weldability not recommended (10/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Ferrium M54 HT-NIT
Is Ferrium M54 easy to machine?
Rough machine in the overaged/annealed condition; in the 55 HRC aged state use rigid setups, coated carbide or CBN at low feeds, or grind/EDM with stress-relief afterwards.
Can Ferrium M54 be welded?
Fusion weldable with matching or Ni-base filler under clean, low-hydrogen conditions, but joints need re-solution/re-age to restore properties — welding is avoided on primary structure.
Can Ferrium M54 be formed, bent or molded?
Hot work (forge/roll) above ~950 °C then anneal; essentially no cold formability at full hardness — shape before hardening.
What surface finishes work on Ferrium M54?
Grind, shot-peen critical fillets, then protect with hard chrome, HVOF WC-Co, Zn-Ni/Cd plate or IVD aluminium; bake after plating to avoid hydrogen embrittlement.
Ferrium M54 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 |
|---|---|---|
| C | 0.28 – 0.34 | 0.3 |
| Co | 6.5 – 7.5 | 7 |
| Ni | 9.5 – 10.5 | 10 |
| Cr | 0.8 – 1.2 | 1 |
| Mo | 1.8 – 2.2 | 2 |
| W | 1.1 – 1.5 | 1.3 |
| V | 0.2 – 0.4 | 0.3 |
| Febalance; P, S, O, N and residuals held very low by VIM+VAR | balance | — |
Ferrium M54 HT-NIT — frequently asked
What is Ferrium M54 HT-NIT used for?
Ferrium M54 HT-NIT is typically used for helicopter transmission gears, high-load shafts and bearings. In short: stronger than AISI 9310; highest-toughness gear steel; 400 °C service capability.
What is the yield strength of Ferrium M54 HT-NIT?
Ferrium M54 HT-NIT has a typical yield strength of 1,725 MPa (250 ksi) and a tensile strength of 2,020 MPa (293 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is Ferrium M54 HT-NIT easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 100% of steel grades). Rough machine in the overaged/annealed condition; in the 55 HRC aged state use rigid setups, coated carbide or CBN at low feeds, or grind/EDM with stress-relief afterwards.
Can Ferrium M54 HT-NIT be welded?
Not readily — weldability is rated not recommended (10/100). Fusion weldable with matching or Ni-base filler under clean, low-hydrogen conditions, but joints need re-solution/re-age to restore properties — welding is avoided on primary structure.
What surface finishes work on Ferrium M54 HT-NIT?
Grind, shot-peen critical fillets, then protect with hard chrome, HVOF WC-Co, Zn-Ni/Cd plate or IVD aluminium; bake after plating to avoid hydrogen embrittlement.
Can Ferrium M54 HT-NIT be formed, bent or molded?
Hot work (forge/roll) above ~950 °C then anneal; essentially no cold formability at full hardness — shape before hardening.
What is the maximum service temperature of Ferrium M54 HT-NIT?
Ferrium M54 HT-NIT is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Ferrium M54-HT and Ferrium M54 ANN-OA?
HT is the default condition — standard fully hardened aerospace condition — pick for landing gear, hook shanks, shafts and actuators needing 2000 MPa with high K_IC. ANN-OA: as-supplied softened bar/billet for rough machining and forming before final hardening. Yield strength is 1,725 MPa in HT versus 950 MPa in ANN-OA.
Sources
- AMS 6516 — Steel, Bars and Forgings, 0.30C-1.0Cr-2.0Mo-1.3W-7.0Co-10Ni (Ferrium M54), Vacuum Induction Melted, Consumable Electrode Remelted — SAE International (2019)
- Ferrium M54 alloy technical data — QuesTek Innovations LLC (2022)
- Ferrium M54 aerospace bar and billet — Carpenter Technology / Latrobe Specialty Metals (2021)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- MMPDS — Metallic Materials Properties Development and Standardization (ultra-high-strength steels chapter) — Battelle/FAA (2023)
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.