NAK80 Steel Detailed Information
NAK80 is a pre-hardened plastic mold steel developed by Daido Steel. It is widely used for high-precision plastic injection molds due to its excellent machinability, high polishability, and superior EDM (electrical discharge machining) performance.
Unlike traditional tool steels, NAK80 is supplied in a pre-hardened state (~40 HRC), eliminating the need for heat treatment. It also features good corrosion resistance and high toughness, making it ideal for precision mold applications.
Key Features
Pre-Hardened (~40 HRC)
- No need for heat treatment, reducing production time and cost.
Excellent Machinability
- Easier to cut than traditional mold steels, extending tool life.
Superior Polishability
- Capable of achieving a mirror-like surface finish, making it ideal for high-gloss plastic molds.
Good Corrosion Resistance
- Better than P20, reducing the risk of rusting in humid environments.
Great EDM Performance
- Produces smooth EDM surfaces, reducing post-processing work.
High Toughness
- Less risk of cracking or chipping under high stress.
Chemical Composition
| Element | Composition (%) |
| Carbon (C) | 0.15 – 0.25 |
| Silicon (Si) | 0.10 – 0.40 |
| Manganese (Mn) | 0.60 – 1.00 |
| Nickel (Ni) | 3.00 – 3.50 |
| Chromium (Cr) | 0.30 – 1.00 |
| Molybdenum (Mo) | 0.20 – 0.50 |
| Aluminum (Al) | ~1.00 |
- Nickel Content (~3.5%) → Enhances toughness and uniform hardness.
- Aluminum Addition → Improves polishability and EDM properties.
- Low Carbon Content → Ensures good machinability and weldability.
Mechanical Properties
| Property | Value |
| Hardness (Pre-Hardened) | 38–43 HRC |
| Tensile Strength | 1,270 MPa (~185 ksi) |
| Yield Strength | 980 MPa (~142 ksi) |
| Toughness | High |
| Machinability | Excellent (Better than P20) |
| Polishability | Excellent (Mirror Finish Capable) |
| Corrosion Resistance | Good (Better than P20) |
- Supplied pre-hardened (~40 HRC), ready for mold production.
- Higher toughness than P20, reducing the risk of cracking.
- Excellent machinability, making it easier to process than traditional mold steels.
NAK80 vs. Other Mold Steels
| Property | NAK80 | P20 (1.2311/1.2312) | S136 (1.2083) | H13 (1.2344) |
| Hardness (HRC) | 38-43 | 28-33 | 50-52 | 45-50 |
| Machinability | Excellent | Good | Moderate | Poor |
| Polishability | Excellent (Mirror Finish) | Good | Excellent | Moderate |
| Corrosion Resistance | Good | Low | High | Moderate |
| Wear Resistance | Moderate | Moderate | High | High |
| Toughness | High | Moderate | Moderate | Very High |
| Applications | Precision molds, high-gloss molding | General mold making | Corrosion-resistant molds | Die-casting, high-temperature applications |
Why Choose NAK80?
- Higher hardness than P20, better wear resistance, and no need for heat treatment.
- Better polishability and EDM finish than P20, ideal for high-gloss molds.
- Good corrosion resistance, making it more durable in humid environments.
Applications
NAK80 is widely used in high-precision plastic molding applications where polishability, machinability, and toughness are essential.
PCPlastic Injection Molds
- High-gloss molds for lenses, cosmetic cases, and medical parts.
- Precision molds for electronic and automotive components.
Blow Molds & Compression Molds
- Molds for plastic bottles, food containers, and packaging.
Precision Molding Tools
- Mold components requiring high wear resistance and smooth EDM surfaces.
Die-Casting & Prototype Molds
- Short-run aluminum die-casting molds.
Engraving & Lettering Molds
- Logos, patterns, and fine details due to excellent polishability.
Heat Treatment Process
NAK80 is pre-hardened (38-43 HRC) and does not require additional heat treatment.
However, if modifications are needed:
Annealing
- Heat to 800–850°C, hold, then slow cool in a furnace.
- Softens the material for machining.
Hardening (If required for special applications)
- Heat to 1000–1050°C, then oil or air quench.
- Temper immediately to achieve desired hardness.
Tempering
- Temper at 450–600°C to balance hardness and toughness.
Alternative Materials
- P20 (1.2311/1.2312) → Lower hardness (~30 HRC), but commonly used in general mold applications.
- S136 (1.2083) → Higher hardness and corrosion resistance, but more difficult to machine.
- H13 (1.2344) → Better for high-temperature applications like die-casting, but harder to polish.
- 420 Stainless Steel → Good corrosion resistance but lower toughness than NAK80.
Conclusion
NAK80 is an outstanding plastic mold steel with high polishability, excellent machinability, and good toughness. It is pre-hardened (~40 HRC), eliminating the need for heat treatment, making it ideal for precision injection molds, high-gloss mold surfaces, and EDM applications.
Best for: High-precision, high-gloss plastic molds.
Why Choose NAK80? Better machinability, polishability, and corrosion resistance than P20.
