1.2311 / P20 – Tool steel for plastic moulds with very good machinability and toughness
Steel 1.2311 (P20) is a pre-hardened tool steel mainly used for plastic moulds. It is supplied in a pre-hardened condition of 28–34 HRC, allowing immediate machining without the need for additional heat treatment.
This grade is tough, easy to machine, offers good thermal conductivity and provides stable quality for medium-sized and large moulds.
Properties of 1.2311 (P20)
🔧 Pre-hardened condition 28–34 HRC
The material is ready for immediate machining, saving both time and production costs.
🛠️ Very good machinability
Its stable structure in the pre-hardened condition ensures consistent chip formation and precise machining.
💥 Good toughness
Suitable for moulds, cores and inserts exposed to pressure and vibration.
🔥 Good thermal conductivity
Efficient heat dissipation improves mould cooling and helps reduce cycle times.
✨ Nitriding possible
The surface hardness can be increased to around 800–1000 HV, improving the service life of cavities and edges.
Chemical composition of 1.2311 (40CrMnMo7)
| Element | Content (%) |
|---|---|
| C | 0.35 – 0.45 |
| Mn | 1.30 – 1.60 |
| Cr | 1.80 – 2.10 |
| Mo | 0.15 – 0.25 |
| Si | 0.20 – 0.40 |
| P | ≤ 0.030 |
| S | ≤ 0.030 |
Typical applications of 1.2311
🧩 Plastic moulds
- medium and large moulds
- core and cavity components
- inserts and segments
🛠️ Forming and pressing tools
- low-pressure moulds
- supporting structural parts of moulds
⚙️ Precision mechanical components
- holders, plates and support segments
- shaped parts requiring good toughness
✨ Applications requiring good surface quality
- polished mould parts
- shapes with high surface finish quality
Heat treatment (guideline values)
Note: In most cases, no additional heat treatment is performed because the steel is supplied pre-hardened.
| Process | Temperature | Note |
|---|---|---|
| Quenching and tempering | 830 – 870 °C + 500 – 600 °C | only for special requirements |
| Nitriding | 480 – 520 °C | surface 800–1000 HV |
| Soft annealing | 700 – 720 °C | hardness approx. 200 HB |
Mechanical properties
- Hardness in supplied condition: 28–34 HRC
- Hardness after nitriding: 800–1000 HV
- Good toughness
- Good thermal conductivity
- Excellent machinability
