Alleima® High-N is a molybdenum and nitrogen alloyed austenitic stainless steel, used for orthopedic implants and fracture fixation devices.
The grade is characterized by:
- Proof strength is up to twice that of Alleima® 316LVM in the annealed condition
- Higher corrosion resistance than Alleima® 316LVM
- High microcleanliness
- Very good surface finish
- Good forgeability
Standards
- UNS: S31675
- BS: 7252-9
Product standard
- ASTM F1586
Chemical composition (nominal)
| C | Si | Mn | P | S | Cr | Ni | Mo | Cu | N | Nb |
|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.06 | ≤0.60 | 4.0 | ≤0.025 | ≤0.003 | 20.5 | 9.5 | 2.4 | ≤0.20 | 0.4 | 0.3 |
Applications
Alleima® High-N grade is used for hip and knee joints and fracture fixation devices.
Corrosion resistance
Alleima® High-N has a very good resistance in physiological environments to:
- General and intergranular corrosion due to high purity and low ferrite content
- Pitting and crevice corrosion due to the high molybdenum content
Alleima® High-N is capable of passing the Moneypenny Strauss corrosion test in accordance with ISO / ASTM requirements.
Forms of supply
Tube
- Bright annealed
- Cold finished
- Ground outside surface
Tolerances
The tolerances for OD and ID, excentricity and straightness are determined in accordance with customers' requirements.
Alleima standard: OD and ID ± 0.04 mm (0.0016 in.); excentricity max. 5%
Other product forms
Alleima High-N can also be supplied as bar.
Mechanical properties
| Product | Condition | Tensile strength | Proof strength | Elongation A, | ||
|---|---|---|---|---|---|---|
| Rm | Rp0,2 | % | ||||
| MPa | ksi | MPa | ksi | |||
| min | min | min | min | typical | ||
| Wire | 1500 max | 217 max | ||||
| Bar | Annealed | 740 | 107 | 430 | 62 | 35 |
| Bar | Medium | 1000 | 145 | 700 | 102 | 20 |
| Bar | Hard | 1100 | 160 | 1000 | 145 | 10 |
| Tube, thick wall | Bright annealed | 740 | 107 | 430 | 62 | min 35 |
| Tube, thick wall | Cold finished | 1200 | 174 | 1100 | 160 | min 10 |
Specific tensile requirements available on request
Physical properties
| Property | ||
|---|---|---|
| Density ( 20 °C) | 8.0 g/cm3 | 0.29 lb/in3 |
| Modulus of elasticity, x103 (20°C) | 200 MPa | 29.0ksi |
| Specific heat capacity (20°C) | 485 J/(kg °C) | 0.11Btu/(lb°F) |
| Thermal conductivity (20°C) | 14W /(m°C) | 8 Btu/(ft h °F) |
| Thermal expansion, x10-6 (30-100°C) | 16.5 per °C | 9.5 per °F |
Machining
| Hardness | Cutting speed range | Feed range | |||
|---|---|---|---|---|---|
| SFM | m/min | IPR | mm/rev | ||
| Turning | 250-400 | 885-145 | 270-45 | 0.002-0.024 | 0.05-0.6 |
| Milling | 250-400 | 855-245 | 260-75 | 0.002-0.016 | 0.05-0.4 |
| Drilling | 250-400 | 115-195 | 35-60 | 0.002-0.012 | 0.05-0.3 |
Disclaimer: Alleima is not providing any products or services that are intended or may be construed to be recommending or otherwise advising on, in any manner, the design, suitability, appropriateness or effectiveness, from a medical/biological/safety perspective, of any medical material, instrument and/or medical device.