Steel Nitralloy N-ANN (Annealed)
Heat-treated state
Pick for deep machining or cold sawing before the customer performs the hardening + nitriding cycle.
Values for the ANN condition
Other Nitralloy N tempers and conditions
Nitralloy N is listed in 5 conditions; see the grade overview at Nitralloy N.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page Annealed | Pick for deep machining or cold sawing before the customer performs the hardening + nitriding cycle. | 520 | 760 | 24 | 217 HB | — |
Normalized | Pick for uniform grain size and dimensional stability in forgings prior to hardening. | 650 | 900 | 20 | 27 HRC | 5.6 % IACS |
QT30-36HRCDefault oil quenched from ~900 °C, tempered ~600 °C | Standard as-stocked condition: machine to near-net size in this state, then gas nitride without further hardening. | 830 | 1,000 | 18 | 33 HRC | — |
Q&T core plus gas-nitrided case (~0.3–0.6 mm) | Final in-service condition: extreme surface hardness, wear and scuffing resistance with high compressive residual stress; case is thin and cannot be reground much. | 1,100 | 1,250 | 13 | 41 HRC | — |
Hardened + aged | Pick when the maximum core strength of the Ni-Al precipitation reaction is needed, e.g. heavily loaded shafts backing a nitrided case. | 1,140 | 1,300 | 14 | 41 HRC | — |
What is Nitralloy N-ANN?
Nitralloy N-ANN is Nitralloy N heat treated to ANN — pick for deep machining or cold sawing before the customer performs the hardening + nitriding cycle. Nitralloy N-ANN has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 67% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi). Nitralloy N-ANN has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F). QT30-36HRC is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Difficult to weld — 18/100, worse than 87% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
- Poor heat conductor — 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades
- Low electrical conductivity — 5.4 % IACS, worse than 81% of steel grades
Nitralloy N-ANN properties
Typical room-temperature values for Nitralloy N-ANN; 11 are specific to this condition. Other listed values are Nitralloy N reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Nitralloy N-ANN has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
Nitralloy N-ANN has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 67% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
Nitralloy N-ANN is rated for continuous service to 500°C (932 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
Nitralloy N-ANN conducts electricity at 5.4 % IACS, worse than 81% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of Nitralloy N-ANN takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
Nitralloy N-ANN's machinability is fair (52/100, better than 52% of steel grades); weldability poor (18/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Nitralloy N-ANN
Is Nitralloy N easy to machine?
Machine fully in the Q&T (30–36 HRC) condition with rigid setups, carbide tooling and generous coolant; leave 0.02–0.05 mm grind stock because nitriding grows the part slightly.
Can Nitralloy N be welded?
Not recommended — high Al and Ni promote oxide entrapment and cracking; if unavoidable, preheat 300–350 °C, use matching or low-hydrogen austenitic filler and re-heat-treat before nitriding.
Can Nitralloy N be formed, bent or molded?
Hot forge 1050–1150 °C with slow cooling and a normalize/anneal afterwards; cold forming is impractical at usable hardness levels.
What surface finishes work on Nitralloy N?
Stress relieve above the final tempering temperature before nitriding; gas nitride 500–540 °C for 20–90 h, then lap or lightly grind the white layer — chrome or oxide finishes may follow but no anodizing.
Nitralloy N 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 | 0.2 – 0.27 | 0.24 |
| Mn | 0.4 – 0.7 | 0.55 |
| Si | 0.2 – 0.4 | 0.3 |
| Cr | 1 – 1.3 | 1.15 |
| Nidistinguishes Nitralloy N from 135/135M | 3.25 – 3.75 | 3.5 |
| Mo | 0.2 – 0.3 | 0.25 |
| Alnitride former; some specifications quote 1.10–1.40 | 1 – 1.3 | 1.15 |
| P | ≤ 0.03 | — |
| Smax; selenium-bearing free-machining versions exist | ≤ 0.03 | — |
| Fe | balance | — |
Nitralloy N-ANN — frequently asked
What is Nitralloy N-ANN used for?
Nitralloy N-ANN is typically used for heavy-duty gears, crankshafts and aircraft engine components. In short: nickel-toughened Nitralloy variant; heavy-section nitriding grade; best for shock loading.
What is the yield strength of Nitralloy N-ANN?
Nitralloy N-ANN has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is Nitralloy N-ANN easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machine fully in the Q&T (30–36 HRC) condition with rigid setups, carbide tooling and generous coolant; leave 0.02–0.05 mm grind stock because nitriding grows the part slightly.
Can Nitralloy N-ANN be welded?
Not readily — weldability is rated poor (18/100). Not recommended — high Al and Ni promote oxide entrapment and cracking; if unavoidable, preheat 300–350 °C, use matching or low-hydrogen austenitic filler and re-heat-treat before nitriding.
What surface finishes work on Nitralloy N-ANN?
Stress relieve above the final tempering temperature before nitriding; gas nitride 500–540 °C for 20–90 h, then lap or lightly grind the white layer — chrome or oxide finishes may follow but no anodizing.
Can Nitralloy N-ANN be formed, bent or molded?
Hot forge 1050–1150 °C with slow cooling and a normalize/anneal afterwards; cold forming is impractical at usable hardness levels.
What is the maximum service temperature of Nitralloy N-ANN?
Nitralloy N-ANN is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Nitralloy N QT30-36HRC and Nitralloy N-ANN?
QT30-36HRC is the default condition — standard as-stocked condition: machine to near-net size in this state, then gas nitride without further hardening. ANN: pick for deep machining or cold sawing before the customer performs the hardening + nitriding cycle. Yield strength is 830 MPa in QT30-36HRC versus 520 MPa in ANN.
Sources
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (nitriding steels) — ASM International (1990)
- ASM Handbook Vol.4A — Steel Heat Treating Fundamentals and Processes (nitriding) — ASM International (2013)
- SAE AMS 6475 / SAE nitriding-steel alloy designations (Nitralloy family) — SAE International (2018)
- Machinery's Handbook — machinability ratings of alloy steels — Industrial Press (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.