Nitinol We Supply

Nitinol is a family of shape memory alloys, which are not completely described using typical engineering properties. In concert with ASTM Standards, it is important that the NiTi specification contain sufficient information to adequately meet the needs of the product for which it is being produced without over specifying properties that are not appropriate.

Current commercially available Nitinol forms include: sheet, tube, wire and ribbon, and components fabricated from each product form.

Nitinol Sheet, Ribbon & Foil

Nitinol Sheet, Foil and Ribbon are the newest and most exciting product forms for this unique shape memory alloy. Nitinol sheet is ideal for laser cutting, etching, stamping and EDM machining. Efficient processing and surface finishing establishes a smooth, light oxide surface. Many new medical innovations are now possible with the use of this very thin and versatile Nitinol form. Sheet is a two-dimensional structure, unlike wire and tube, giving us design options like stamping, punching, and deep drawing.

Dimension: Thickness ≥ 0.1 mm, Width ≤ 200 mm
Alloys: Superelastic and Shape Memory available.
Temperature Range ( Af ): - 20 ~ 100 deg. C
Surface: Natural Oxide, Pickled/Etched and Customer Specific Requirements
Thermomechanical Conditions: As Cold-Worked, Straight Strain Annealed and Shape Set Annealed.
Certification: Transformed Temperatures, Tensile Properties, Chemical Composition and Customer Specific Requirements

Application of Nitinol Sheet & Foil
Nitinol sheet is ideal for laser cutting, etching, stamping and EDM machining. Efficient processing and surface finishing establishes a smooth, light oxide surface.
Many new medical innovations are now possible with the use of this very thin and versatile Nitinol form. Sheet is a two-dimensional structure, unlike wire and tube, giving us design options like stamping, punching, and deep drawing. JM will work with you to fabricate Nitinol sheet to your specifications, with sheet as thin as 0.002"

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Nitinol Wire & Rod

Nitinol wire is the most mature form of this unique superelastic and shape memory alloy, being commercialized in the mid 1980's. It is available in many different sizes, alloys and finishes. And, shape memory or superelastic forms are both offered. Niti shape memory alloys are gaining increasing use in the medical device industry for Nitinol catheter stents, guidewires and other critical applications.

Dimension: Diameter ≥ 0.1 mm
Alloys: Superelastic and Shape Memory available.
Temperature Range ( Af ): - 20 ~ 100 deg. C
Surface: Natural Oxide, Pickled/Etched, Polished, Customer Specific Requirements
Thermomechanical Conditions: As Cold-Worked, Straight Strain Annealed and Shape Set Annealed.
Certification: Transformed Temperatures, Tensile Properties, Chemical Composition and Customer Specific Requirements

Application of Nitinol Wire & Rod
Nitinol wire and rod are widly used for medical and other industries. Such as eyeglass frames, cellular phone antennae, bra underwire, implantable devices, bone staples, vascular stents, guide wires, stents orthodontic arches, implantable active devices, surgical tools,and thermostats coffeepots etc.

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Nitinol Tubing

Nitinol tubing was first manufactured commercially in the early 1990's. Since then, the application have reached unprecedented levels and continue to rise today. Due to Nitinol's unique properties it has seen a large demand for use in less invasive medical devices. Nitinol tubing is commonly used in catheters, stents, and superelastic needles. Today, it offers the best compromise between engineered plastics and traditional metals.
Compared to other alloys tubing technologies Nitinol tubing technology is fairly recent but has many advantages over stainless steel hypotube.
Kink and crush resistance, Flexibility, Large amount of recoverable deformation, Generation of constant or low forces over a wide range of deformation, Energy storage and restoration.

Dimension: Out Diameter 1.5 ~ 10 mm, Wall Thickness ≥ 0.2 mm.
Alloys: Superelastic, Shape Memory Available and Custom Alloy Formulations
Temperature Range ( Af ): - 20 ~ 100 deg. C
Surface: Natural Oxide, Pickled/Etched, Centerless Ground and Mechanically-cleaned
Thermomechanical Conditions: As Cold-Worked, Straight Strain Annealed and Shape Set Annealed.
Certification: Transformed Temperatures, Tensile Properties, Chemical Composition and Customer Specific Requirements

Applications for Nitinol Tubing
Formed Tubing Shapes, Beveled Needle Points, Cut Lengths, Catheter Shafts, Distal Protection, Laproscopes, Endoscopic Guide Tubes and Orthodontic Guidewires etc.

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ASTM Standards

ASTM International, in conjunction with the Nitinol community, has issued several standards that aid in specifying requirements for Nitinol.

ASTM F 2004-05: Standard Test Method for Determination of Transformation Temperature of Nickel-Titanium Shape Memory Alloys by Thermal Analysis
ASTM F 2004-05: Standard Terminology for Nickel-Titanium Shape Memory Alloys
ASTM F 2063-05: Standard Specification for Wrought Nickel-Titanium Shape Memory Alloys for Medical Devices and Surgical Implants
ASTM F 2633-07: Standard Specification for Wrought Nickel-Titanium Shape Memory Alloy Tube for Medical Devices and Surgical Implants
ASTM F 2082-06: Standard Test Method for Determination of Transformation Temperature of Nickel-Titanium Shape Memory Alloys by Bend and Free Recovery
ASTM F 2516-07: Standard Test Method for Tension Testing of Nickel-Titanium Superelastic Materials

ASTM F 2004 Commentary
This specification provides guidance on the determination of transformation temperature of fully annealed materials, and is not appropriate for testing products that are heat treated to impart superelasticity. A sample can be solution annealed and tested, but the transformation temperature will be that of the ingot, not product. There is also controversy over the exact temperature, time, and protective gas used during solution annealing. Please contact Seabird should you have questions regarding test methods to ensure compliance.

ASTM F 2063-05 Commentary
From its inception, ASTM F 2063 was created to govern the manufacture of wrought products, not finished products. There is an ongoing debate in the industry as to whether it properly specifies chemistry and inclusion size and distribution. Seabird supports ASTM 2063-05 as a raw material specification only. It is important to discuss this topic prior to adding to an existing or new specification.


Superelastic Nitinol

This product form takes advantage of the stress-induced martensitic transformation to achieve incredible amounts of flexibility, strain recovery, and kink resistance. Nitinol behaves superelastically if the Active A(f) temperature is below its use temperature. Applications that are intended to be superelastic at room temperature are generally produced with an Active A(f) temperatures below room temperature in the range of 0 C to 20 C. A superelastic material will remain superelastic up to a temperature from the Active A(f) to a temperature about 50 C above Active A(f). Therefore a material with an Active A(f) of about 15 C will exhibit good superelasticity up to about 65 C. Please contact Seabird for more information regarding the use of Alloys.

Shape Memory Nitinol

This product form exhibits the ability to recover a shape upon heating above Active A(f). Therefore, the most critical property to specify is the Active A(f). This represents the finish of the transformation from martensite to austenite upon heating, and therefore the temperature at which the shape recovery is also complete. The start of the transformation upon heating is the Austenite Start Temperature, A(s), and is about 15 C to 20 C lower than the Active A(f).
Upon cooling, there are comparable start and finish transformation temperatures for the reverse transformation from austenite to martensite. These are known as M(s) and M(f), respectively. The M(f) temperature is about 15 C to 20 C lower than M(s). There is a hysteresis in the transformation, meaning that the transformation to martensite upon cooling is below the temperature at which the martensite reverts to austenite upon heating. For binary shape memory materials, the difference between M(p) and A(p) is 25 C to 50 C. There is a peak in the transformations from austenite to martensite, and martensite to austenite, and this information is captured as A(p) and M(p) temperatures during DSC testing per ASTM F2004.


Typical Mechanical Properties of standard Superelastic NiTi Wires**

Materials Typical as Drawn Properties* Typical as Straight Annealed Properties*
UTS

(KPSI)

Elongation at Failure (%) UTS

(KPSI)

Elongation at Failure (%) Loading Plateau (KPSI) Unloading Plateau (KPSI) Residual Strain Percent
Cr Doped 270 +/-15 6% Min 220 +/-15 12% Min 70 Min

 

~50 < 0.25
A(f) 10 ℃ 270 +/-15 6% Min 210 +/-15 12% Min 65 Min ~30

(15~45)

< 0.25
A(f) 20 ℃ 250 +/-15 6% Min 270 +/-1 12% Min 65 Min ~20

(5~35)

< 0.25

* All properties are measured at room temperature. The loading and unloading plateaus for straight annealed materials will be approximately 10 KPSI to 20 KPSI higher at 37 C.

** Properties for sheet may be different.