Fort Wayne Metals

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Nitinol Wire

Fort Wayne Metals manufactures wire products from various grades of Nickel-Titanium or Nitinol commonly used in medical applications  (Nitinol #1, Nitinol #2Nitinol #4 and Nitinol #8) as well as Nitinol #5, Nitinol #6, and Nitinol #9 for other various applications. All grades of Nitinol are available in either the cold worked (CW) condition ready for heat treatment or as straightened super-elastic (SE) wire. A newer technique yielding unique mechanical characteristics for Nitinol  has been developed by Fort Wayne Metals called Dynamic Plateau Strength (DPS). This process is available as well. If you need an exceptionally smooth surface we suggest Silk™ Nitinol Wire, which achieves a surface texture of 3µin RMS without mechanical or electropolishing. 

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:

GradeApplication
Nitinol #1 Guidewires, stents, stylets, forming mandrels, stone retrieval baskets, orthodontic files, etc.
Nitinol #2* Ideal for applications that require a high loading and unloading plateau stresses at room temperature.
Nitinol #3** Applications requiring increased stiffness.
Nitinol #4 Provides the best cycling performances at body temperature (37°C), for example in orthodontic arch wires.
Nitinol #5 A common application for this alloy is high temperature actuators.
Nitinol #6 A common application for this alloy is high temperature actuators.
Nitinol #8 Ideal for applications that require a phase transformation at body temperature (37°C).
Nitinol #9 For use in very cold temperature environment applications.

* Typical chemical composition: ASTM F2063 Exc. Cr 0.2% to 0.3%
** Typical chemical composition: ASTM F2063 Exc. Co 1% to 2%


Super-Elastic Alloys – Mechanical Properties

 CW = (Cold Worked)SE = (Super-Elastic )
ProductIngot As (°C)UTS (psi)Elongation
(%)
UTS (psi)Elongation (%)Loading Plateau (psi)Unloading Plateau (psi)Active Af (°C)
Notes Permanent Set < 0.5% after strained to 8%

Results are typical for round wire diameters from 0.001" (0.025 mm) to ≤ 0.040" (1.016 mm).
All Mechanical testing conducted at 22°C ± 2°C

* Typical target

Niti#1  -35 to -10 200,000 min >4% 180,000 min > 10% > 70,000 > 20,000 +10 to +18
Niti#2  -45 to -15 250,000 min >4% 210,000 min > 10% > 80,000 > 35,000 0 to +18
Niti#3  -80* 200,000 min >5% 190,000 min > 10% > 100,000 > 60,000 -15*
Niti#4  -10 to +10 220,000 min >4% 180,000 min > 10% > 65,000 > 7,000 +14 to +22
Niti#9  ≤ -35 220,000 min >4% 160,000 min > 10% > 75,000 > 25,000 ≤0

 

Shape Memory Alloys – Mechanical Properties

 CW = (Cold Worked)SM = (Shape Memory)
ProductIngot As
(°C)
UTS (psi)Elongation
(%)
UTS (psi)Elongation (%)Loading Plateau (psi)Active Af (°C)
Notes Permanent Set < 0.5% after strained to 8%

Results are typical for round wire diameters from 0.001" (0.025 mm) to ≤ 0.040" (1.016 mm).
All Mechanical testing conducted at 22°C ± 2°C

Niti#5   +85 220,000 min >3% 160,000 min > 10% N/A  +85
Niti#6  +35 to +85 220,000 min >3% 160,000 min > 10% N/A +40 to +80
Niti#8  +10 to +35 220,000 min >3% 160,000 min > 10% N/A +22 to +40


Typical Chemistry

Nitinol #1 - Typical Chemistry for Surgical Implants

 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 0.190"
  • Flat Wire – Aspect Ratio: W/T < 10
  • Rolled Strip – Aspect Ratio: W/T  >10:1
  • Minimum Thickness: 0.0003"
  • Maximum Width: 0.450"
  • Turkshead: Square, Rectangular
  • Custom Shapes: A wide variety of shaped cross-sectional wire
  • HHS® Tube
  • Stranded Cables: 1x3, 1x7, 1x19, Materials Blends, etc.
  • DFT: Composites manufactured with a Nitinol core or a clad jacket
  • Silk™ Nitinol – surface texture of 3µin RMS or less

If your Nitinol product need falls outside of the standard medical grade material or the available product forms, please contact us.

Surface Finishes Available

  • Light Oxide - diamond drawn surface
  • Dark Oxide - diamond drawn surface
  • Black Oxide - diamond drawn surface
  • Etch – chemical removal of oxide layer - will retain smooth surface
  • Pickled – chemical removal of oxide layer along with a slight amount of base metal - surface will have a rough texture
  • Etched and Mechanically Polished –  Chemical removal of oxide layer followed by mechanical polish - surface will have stainless steel appearance (although at >40x magnification, micro scratches will be present
  • Oxide-free – smooth and without visible oxide (Silk™ Nitinol)

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)


Nitinol Wire

 

Questions about Nitinol?

We'll be happy to help. Please contact us for more information.