Medical Grade Nitinol Wire for Super-Elastic Applications
Fort Wayne Metals manufactures three medical grades (NiTi#1, NiTi#2 and NiTi#4) of Nickel-Titanium or Nitinol wire products available in either the cold worked (CW) condition ready for heat treatment or as straightened super-elastic (SE) wire.
Each medical grade of Nitinol material is comprised of near equal atomic weight percentage of nickel and titanium. Our most common medical grade, NiTi#1 exceeds chemistry requirements set forth by ASTM F2063 for use in surgical implants. At Fort Wayne Metals, all incoming Nitinol raw materials are inspected to ensure they meet proprietary internal specifications for chemistry, ingot transformation temperature, material homogeneity, and microstructure. Optimized to promote an exceptionally smooth and uniform surface finish quality, all wire products utilize a proprietary single and multi crystalline diamond drawing die technology. Medical grade Nitinol wire may be purchased in the cold worked (CW) or the super-elastic condition (SE) and after the correct super-elastic heat treatment will accommodate strain up to 8% without permanent kinking at body temperature. The transformation temperatures and mechanical properties for each of our three standard grades of Nitinol are presented in the table at the bottom of the page.
Nitinol Wire Applications
Our Nitinol wire is used for many different medical and industrial applications. The table below gives some typical engineering applications for each of our standard Nitinol medical grades:
| Grade | Application |
|---|---|
| NiTi#1 | Guidewires, stents, stylets, forming mandrels, stone retrieval baskets, orthodontic files, etc. |
| NiTi#2 | Ideal for applications that require a high loading and unloading plateau stresses at room temperature, cell phone antennae, eyeglass frames. |
| NiTi#4 | Provides the best cycling performances at 37°C at body temperature. |
Mechanical Properties
| CW = (Cold Worked) | SE = (Super-Elastic Straight) | ||||||
|---|---|---|---|---|---|---|---|
| Product | Ingot As (°C) | UTS (psi) | UTS (psi) | Elongation (%) | Loading Plateau (ksi) | Unloading Plateau (ksi) | Active Af (°C) |
| Notes | Elongation at break > 4% | Permanent Set < 0.5% after strained to 8%, Elongation at break > 10% |
|||||
| All Mechanical Testing Conducted at 22°C ± 2°C | |||||||
| Niti#1 (N1) | -35 to -10 |
200,000 min | 180,000 min | > 10% | > 70,000 | > 20,000 | +10 to +18 |
| Niti#2 (N1) | -45 to -15 |
250,000 min | 210,000 min | > 10% | > 80,000 | > 35,000 | 0 to +18 |
| Niti#4 (N1) | -10 to +10 |
200,000 min | 180,000 min | > 10% | > 65,000 | > 15,000 | +14 to +22 |
Typical Chemistry
| ASTM F2063 | FWM NiTi#1 (Average) | |
|---|---|---|
| Nickel | 54.5-57.0 wt% | 56.0 wt% |
| Carbon | 500 ppm | 330 ppm |
| Oxygen | 500 ppm | 280 ppm |
| Hydrogen | 50 ppm | 25 ppm |
| Titanium | Balance | Balance |
Certification Data Package
- UTS-Elongation
- Upper and lower plateau stress (SE only)
- Fully annealed ingot transformation measured by DSC
- Wire transformation measured by Bend and Free Recovery (SE only)
- Multiple test temperatures available i.e. 22°C ±2°C or 37°C ±2°C
- Permanent set after straining to 6% or 8% strain (SE only)
- Multiple gauge length and crosshead speeds
- Chemical analysis
Nitinol Product Forms
- Round Wire: 0.0005" to 0.250"
- Flat Wire: Aspect Ratio: W/T ~ 12
- Minimum Thickness: 0.0003"
- Maximum Width: 0.200"
- Turkshead: Square, Rectangular
- Custom Shapes: A wide variety of shaped cross-sectional wire
- Stranded Cables: 1x3, 1x7, 1x19, Materials Blends, etc.
- DFT: Composites manufactured with a Nitinol core or a clad jacket
If your Nitinol product need falls outside of the standard medical grade material or the available product forms, please contact one of our Nitinol application sales engineers.
Surface Finishes Available
- Light Oxide: (LO) Gold to Brown color - diamond drawn surface
- Dark Oxide: (DK) Grey to Black color - diamond drawn surface
- Black Oxide: (BLK) Shiny Black color - diamond drawn surface
- Etch: (E) chemical removal of oxide layer - will retain smooth surface
- Pickled: (P) chemical removal of oxide layer along with a slight amount of base metal - surface will have a rough texture
- Etched and Mechanically Polished: (EMP) Chemical removal of oxide layer followed by mechanical polish - surface will have stainless steel appearance (although at >40x magnification, micro scratches will be present
Additional Services Available
- Wire Cleaning: hot alkaline or alcohol wipe
- Continuous eddy current analysis
- Rotary beam fatigue testing
- Metallurgical lab testing
- X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Auger Electron Spectroscopy (AES), Scanning Electron Microscope (SEM), Electron Dispersive Spectroscopy (EDS)
How to Specify and Order Medical Grade Nitinol Round Wire
Wire Diameter
Specify Std. Wire diameter < 0.040" (4 decimal places) (Std Wire Tolerance per ASTM A-555)
Nitinol Grade
Condition
- Cold Worked
- Super-Elastic
Surface Finish
- LO - Light Oxide
- DK - Dark Oxide
- BLK - Shiny Black
- E - Etched Bright
- P - Pickled
- EMP - Etched and Mechanically Polished
Call our customer service department for a quotation today.
Customer Commitment
As a leading manufacturer of medical grade wire, we fully support our customers’ requirements for quality, service, reliability, dependability, as well as research and development projects. We are FDA and ISO 9001:2001 registered. We are fully capable of statistical process controls and just-in-time inventory scheduling. At Fort Wayne Metals, we are committed to working with each of our customers to ensure that we meet their specific needs.
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