Fort Wayne Metals manufactures numerous medical grades of Nickel-Titanium or Nitinol wire products. All grades are available in either the cold worked (CW) condition ready for heat treatment or as straightened super-elastic (SE) wire.
Fort Wayne Metals offers different grades of Nitinol, which are distinguished by the austenite start temperature of the ingot:
Nitinol #1 (superelastic) -35 to -10 °C
Nitinol #2 (superelastic) -45 to -15 °C
Nitinol #4 (superelastic) -10 to +10 °C
Nitinol #5 (shape memory) ≥ +85 °C
Nitinol #6 (shape memory) +35 to +85 °C
Nitinol #8 (shape memory) +10 to + 35 °C
Nitinol #9 (superelastic) ≥ +35 °C
Each medical grade of Nitinol material is comprised of near equal atomic weight percentage of nickel and titanium. With the exception of Nitinol #2 all available grades meet the chemistry requirements set forth by ASTM F2063 for use in surgical implants. Nitinol #2 is chromium doped to lower its
transformation temperature, which means that the chromium content of 0.20-0.30 weight% exceeds the 0.01% specified in ASTM F2063.
Fort Wayne Metals inspects all incoming Nitinol raw materials 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 superelastic heat treatment will accommodate strain up to 8% without permanent deformation at body temperature.
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 Examples
Nitinol #1 Guidewires, stents, stylets, forming mandrels, stone retrieval baskets, orthodontic files
Nitinol #2 Applications that require a high loading and unloading plateau stresses at room temperature such as eyeglass frames.
Nitinol #4 Provides the best cycling performances at body temperature (37°C), like orthodontic arch wires.
Nitinol #5 High temperature actuators
Nitinol #6 High temperature actuators
Nitinol #8 Applications that require a phase transformation at body temperature (37°C)
Nitinol #9 Very cold temperature environment applications
Certification Data Package
Upper and lower plateau stress (SE only)
Fully annealed ingot transformation measured by DSC
Wire transformation measured by Bend & Free Recovery (SE only)
Two test temperatures available: 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: 0.450"
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 clad jacket
Light Oxide (LO) Gold to Brown color - diamond drawn surface
Dark Oxide (DK) Blue to Black color - diamond drawn surface
Black Oxide (BLK) Shiny Black color - diamond drawn surface
Etch (E) Chemical removal of oxide layer - will maintain smooth surface
Pickled (P) Chemical removal of oxide layer along with a slight amount of base metal - surface will have 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 are present
ASTM A555 Standard Specification for General Requirements for Stainless Steel Wire and Wire Rods
ASTM F2005 Standard Terminology for Nickel-Titanium Shape Memory Alloy
ASTM F2004 Standard Test Method for Transformation Temperature of Nickel-Titanium Alloys by Thermal Analysis
ASTM F2063 Standard Specification for Wrought Nickel-Titanium Shape Memory Alloys for Medical Devices
and Surgical Implants
ASTM F2516 Standard Test Method for Tension Testing of Nickel-Titanium Super-Elastic Materials
When your application requires a Nitinol wire with increased stiffness, Fort Wayne Metals offers two options – DPS™ Nitinol wire and USN™ wire. Both options will produce straight wire with 1:1 torque response.
Dynamic Plateau Strength Nitinol
DPS™ Nitinol wire allows device designers to achieve a high stiffness in applications requiring between 1% and 8% strain when the material enters
the plateau region on a stress-strain curve. DPS™ Nitinol wire is available in diameters from 0.009" – 0.030" and in discrete lengths from .5" to 144".
In applications where the gradual bend of the wire produces less than 1% strain and only enters into the modulus region of the stress-strain curve, USN™ wire will show an increased stiffness when compared to our superelastic Nitinol #1. USN™ wire is available diameters from 0.009" – 0.030" on spools in lengths up to 8,000'.