Nitinol #2

This specification covers the information typically necessary to purchase Chrome Doped Nitinol #2 round wires with a diameter ≥ 0.001" (0.025 mm) and ≤ 0.040" (1.016 mm).

Product Definition
NiTi#2-CW Nitinol #2 Cold Worked
NiTi#2-SE Nitinol #2 Super-Elastic Straight Annealed

Add desired suffix to select oxide finish as described below in Surface Finishes.

Applicable Documents
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 F2516 Standard Test Method for Tension Testing of Nickel-Titanium Super-Elastic Materials

Chemical Composition


The chemical composition of the material shall be equal to or better than those defined by ASTM F2063 with the exception of the chromium content, which is higher than the .01% maximum ASTM specification. Fort Wayne Metals meets or exceeds the following chemical composition requirements:

Element Weight %
Nickel 55.8 (Reference)
Titanium Balance
Chromium 0.20 to 0.30 (exceeds ASTM F2063: .01% max.)
Carbon < 0.05 (500 PPM maximum)
Nitrogen plus Oxygen < 0.05 (500 PPM maximum)
Iron < 0.05 (500 PPM maximum)
Copper < 0.01 (100 PPM maximum)
Cobalt < 0.05 (500 PPM maximum)
Hydrogen < 0.005 (50 PPM maximum)
Niobium < 0.025 (250 PPM maximum)
Any Single Trace Element < 0.1 (except Chromium)
Total Trace Elements < 0.4 (except Chromium)

Transformation Properties

The fully annealed ingot austenite start (As) temperature shall be (-65)°C to (0)°C when measured by DSC in accordance with ASTM F2004.

Materials ordered in the Super-Elastic Straight Annealed (NiTi#2-SE) condition will have a finish Af temperature between +0°C to +18°C when tested per FWM procedures.

Applicable Wire Sizes and Standard Tolerances

(in accordance with ASTM A-555)

Specified Size (inches) Standard Tolerance (inches)
1) Tighter tolerance available upon request.
2) Out of round tolerance shall be one-half the total size tolerance
0.035 to 0.024 ± 0.0005
< 0.024 to 0.012 ± 0.0004
< 0.012 to 0.008 ± 0.0003
< 0.008 to 0.0048 ± 0.0002
< 0.0048 to 0.001 ± 0.0001

Mechanical Properties

All Mechanical Testing Conducted at 22°C ±2°C

Cold Worked NiTi #2 Wire

The cold worked wire shall conform to the following mechanical properties:

Cold Work 45% ±5%
Ultimate Tensile Strength 250,000 PSI minimum
Tensile Elongation at Failure 4% minimum (as measured by the above referenced document)

Super-Elastic NiTi #2 Wire
Ultimate Tensile Strength > 210,000 PSI
Elongation at Break > 10%
Loading Plateau > 80,000 PSI at 4% strain
Unloading Plateau > 35,000 PSI at 4% strain (after an initial strain to 8%)
Permanent Set after 8% Strain and Unloading < 0.5%

Surface Finish and Appearance
Description Order Code Suffix Appearance
Eched and Mechanically Polished EMP Silver
Etched Bright E Bright Silver
Light Oxide LO Gold to Brown
Pickled P Matte Silver
Dark Oxide DK Blue to Black
Black Oxide BLK Shiny Black

Wire must be clean of contaminants, smooth, free from bumps, kinks, waves, scrapes, splits, burrs and other surface defects.

Quality Assurance Provisions

Each lot of material is to be manufactured from a single source of raw material under known process conditions.

Supplier will be notified of any revision changes to this specification.

Certification and Spool Labeling

A certificate of compliance to this product number shall accompany each shipment.

Each spool shall be labeled with the:

  • Product Type
  • Fort Wayne Metals Batch #
  • Fort Wayne Metals Part #
  • Size
  • Feet or Pounds (as applicable)


The wire must be wound evenly on the spools, with no breaks or tangles.

The maximum weight per spool shall be as follows unless specified otherwise on the purchase order.

Wire Size Maximum Weight Spool Type
0.0007" to 0.003" 0.5 pounds 2.5"x3", Din 80, Din 100, Din 125, Steeger, NE #2, Wardwell Bobbins
> 0.003" to < 0.012" 5 pounds 2.5"x3", Din 100, Din 125, Weldwire Reel
> 0.012" to 0.018" 10 pounds Weldwire Reel
>0.018" to 0.035" 20 pounds Weldwire Reel