1.8550 / 34CrAlNi7 – Premium nitriding steel with extremely high surface hardness
Steel 1.8550 (34CrAlNi7 / 34CrAlNi7-10) is a highly alloyed nitriding steel designed for the most demanding components requiring an extremely hard surface, maximum wear resistance, and at the same time a tough and durable core.
Thanks to its content of aluminium, chromium and nickel, this grade is one of the best nitriding steels on the market. After nitriding, it can achieve extremely hard surface layers of approximately 900–1100 HV, making it ideal for highly precise and heavily loaded parts.
Properties of 1.8550 (34CrAlNi7)
⚙️ Extremely high surface hardness after nitriding (900–1100 HV)
The high aluminium content enables the formation of a very hard and stable nitride layer.
🔩 High core strength
The core remains tough and resistant to shock, making this steel ideal for precise rotating components.
🔥 Excellent thermal stability of the nitride layer
The nitrided layer is highly stable at elevated temperatures and therefore suitable for parts exposed to long-term heating.
🛡️ Very high wear resistance
The nitrided surface provides exceptional resistance to friction and abrasive wear.
📏 High dimensional stability
Minimal distortion after nitriding makes this steel especially suitable for high-precision components.
Chemical composition of 1.8550 (34CrAlNi7)
| Element | Content (%) |
|---|---|
| C | 0.30 – 0.37 |
| Cr | 1.20 – 1.50 |
| Al | 0.90 – 1.30 |
| Ni | 0.50 – 0.80 |
| Mn | 0.30 – 0.60 |
| Si | 0.10 – 0.40 |
| Mo | ≤ 0.10 |
| P | ≤ 0.025 |
| S | ≤ 0.035 |
Typical applications of 1.8550
⚙️ High-precision rotating components
- shafts
- pins
- guides and sliding parts
🔩 Components with extreme wear exposure
- small-module gears
- cams and cam systems
- precision transmission components
🏭 Mechanical engineering and energy industry
- spindles
- guide bushes and bearing bushes
- control components of mechanical systems
🚗 Automotive and hydraulics
- piston pins
- guide elements and sliding bodies
- heavily loaded precision parts
Heat treatment (guideline values)
| Process | Temperature | Note |
|---|---|---|
| Quenching and tempering | 820 – 860 °C hardening → 550 – 650 °C tempering | higher core strength |
| Nitriding | 480 – 530 °C | surface hardness 900–1100 HV |
| Ion / plasma nitriding | 450 – 580 °C | very uniform layer |
| Soft annealing | 650 – 700 °C | improved machinability |
Mechanical properties
- Surface hardness after nitriding: 900–1100 HV
- Core hardness: approx. 200–300 HB
- Tensile strength Rm (after quenching and tempering): 900–1100 MPa
- Elongation A: 12–15%
- High fatigue resistance
Why choose 1.8550 / 34CrAlNi7?
1.8550 is an excellent choice for demanding technical applications where extreme surface hardness, high wear resistance, thermal stability and dimensional accuracy are essential. It is especially suitable for high-precision nitrided components used in mechanical engineering, power transmission, hydraulics and automotive applications.
