Steel NAK80 Nitrided
Finish state
Pick when abrasive glass/mineral-filled resins demand a wear-resistant cavity surface while keeping the 40 HRC tough core.
Values for the Nitrided condition
Other NAK80 tempers and conditions
NAK80 is listed in 4 conditions; see the grade overview at NAK80.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault softened for heavy machining (approx. 25–30 HRC) | Rarely stocked; used when very heavy roughing or cold work is needed before re-solution-treating and aging back to 40 HRC. | 700 | 900 | 18 | 28 HRC | — |
Pre-hardened | Standard stock condition: machine straight to finished cavity, no heat treatment and no distortion risk. | 1,150 | 1,300 | 12 | 40 HRC | — |
NitridedThis page pre-hard core with gas/plasma nitrided case (~900–1000 HV surface) | Pick when abrasive glass/mineral-filled resins demand a wear-resistant cavity surface while keeping the 40 HRC tough core. | 1,150 | 1,300 | 10 | 40 HRC | 5.7 % IACS |
Quenched and tempered | Re-heat-treatment route after weld repair or after machining in the soft state; restores full pre-hard properties. | 1,180 | 1,330 | 11 | 41 HRC | 5.7 % IACS |
What is NAK80 Nitrided?
NAK80 Nitrided is NAK80 supplied in the Nitrided condition — pick when abrasive glass/mineral-filled resins demand a wear-resistant cavity surface while keeping the 40 HRC tough core. NAK80 Nitrided has a yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi). NAK80 Nitrided 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). Annealed is the default condition FabDigit quotes; Nitrided is available on request or by drawing note.
Advantages
- High strength — 1,150 MPa (167 ksi), better than 94% of steel grades
- Good corrosion resistance — 28/100, better than 94% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High service temperature — 450°C (842 °F), better than 86% of steel grades
Limitations
- Difficult to machine — 10/100, worse than 99% of steel grades
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 3/100, worse than 99% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
NAK80 Nitrided properties
Typical room-temperature values for NAK80 Nitrided; 23 are specific to this condition. Other listed values are NAK80 reference data and may not represent this condition. Bars are the position among steel grades.
Physical2
NAK80 Nitrided 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
NAK80 Nitrided has a yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
NAK80 Nitrided is rated for continuous service to 450°C (842 °F). It conducts heat at 30 W/m·K (17.3 BTU/hr·ft·°F), worse than 83% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
NAK80 Nitrided conducts electricity at 5.7 % IACS, worse than 80% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (28/100), better than 94% of steel grades.
Sustainability4
Producing a kilogram of NAK80 Nitrided takes about 36 MJ of energy and emits 2.6 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 30%.
Manufacturability7
NAK80 Nitrided's machinability is not recommended (10/100, worse than 99% 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 NAK80 Nitrided
Is NAK80 easy to machine?
Machine directly at 40 HRC with coated carbide (or CBN for finishing); rigid setups, 60–120 m/min, light radial engagement — EDM and engraving behave well and no post-heat-treat distortion allowance is needed.
Can NAK80 be welded?
Repairable by TIG or laser with matching NAK80/maraging-type filler; preheat 250–350 °C, low heat input, then re-age ~500 °C ×3–5 h to recover cavity hardness and colour match.
Can NAK80 be formed, bent or molded?
Supplied in the hardened condition, so no cold forming — shape by milling, EDM, grinding; hot working (1100→900 °C forge) only at the mill followed by solution + aging.
What surface finishes work on NAK80?
Excellent mirror polishability (Ra <0.01 µm achievable, #10000 attainable) thanks to low sulfur and fine uniform structure; accepts texturing/etching, hard chrome or electroless nickel for corrosive resins, and nitriding or PVD for wear.
NAK80 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 | 0.1 – 0.2 | 0.15 |
| Si | 0.1 – 0.5 | 0.3 |
| Mn | 1.2 – 1.8 | 1.5 |
| Niwith Al and Cu forms the precipitation-hardening system | 2.5 – 3.5 | 3 |
| Cu | 0.8 – 1.2 | 1 |
| AlNi-Al intermetallic aging response | 0.8 – 1.2 | 1 |
| Mo | 0.15 – 0.4 | 0.3 |
| Skept low (non-free-cutting) for mirror polishability, unlike NAK55 | ≤ 0.01 | 0.01 |
| P | ≤ 0.03 | 0.02 |
| Fe | balance | — |
NAK80 Nitrided — frequently asked
What is NAK80 Nitrided used for?
NAK80 Nitrided is typically used for injection moulds for high-gloss transparent parts, optical lens moulds, precision cavity and core inserts, cosmetic and consumer housing moulds, photo-etched and textured cavity plates and medical device moulds. In short: premium mirror-polish mold.
What is the yield strength of NAK80 Nitrided?
NAK80 Nitrided has a typical yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is NAK80 Nitrided easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 99% of steel grades). Machine directly at 40 HRC with coated carbide (or CBN for finishing); rigid setups, 60–120 m/min, light radial engagement — EDM and engraving behave well and no post-heat-treat distortion allowance is needed.
Can NAK80 Nitrided be welded?
Not readily — weldability is rated not recommended (10/100). Repairable by TIG or laser with matching NAK80/maraging-type filler; preheat 250–350 °C, low heat input, then re-age ~500 °C ×3–5 h to recover cavity hardness and colour match.
What surface finishes work on NAK80 Nitrided?
Excellent mirror polishability (Ra <0.01 µm achievable, #10000 attainable) thanks to low sulfur and fine uniform structure; accepts texturing/etching, hard chrome or electroless nickel for corrosive resins, and nitriding or PVD for wear.
Can NAK80 Nitrided be formed, bent or molded?
Supplied in the hardened condition, so no cold forming — shape by milling, EDM, grinding; hot working (1100→900 °C forge) only at the mill followed by solution + aging.
What is the maximum service temperature of NAK80 Nitrided?
NAK80 Nitrided is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between NAK80 Annealed and NAK80 Prehard?
Annealed is the default condition — rarely stocked; used when very heavy roughing or cold work is needed before re-solution-treating and aging back to 40 HRC. Prehard: standard stock condition: machine straight to finished cavity, no heat treatment and no distortion risk. Yield strength is 700 MPa in Annealed versus 1,150 MPa in Prehard.
Can FabDigit make parts in NAK80 Nitrided?
Yes — NAK80 Nitrided is available for CNC machining; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- NAK80 Pre-hardened Mirror-finish Plastic Mold Steel — Daido Steel (2020)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- Tool Steels, 5th ed. — ASM International (1998)
- Mold steel comparison tables (NAK80 / P20 / 718H) — Ensinger–Hasco style tooling data compilations (2022)
- (NAK80/718H/P20) (2025)
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.