【国外标准】 Standard Specification for Wrought Nickel-Titanium Shape Memory Alloys for Medical Devices and Surgical Implants

This specification covers the chemical, physical, mechanical, and metallurgical requirements for wrought nickel-titanium bar, flat rolled products, and tubing containing nominally 54.5 % to 57.0 % nickel and used for the manufacture of medical devices and surgical implants. The material shall be made from ingot made from nickel and titanium with no other intentional alloy additions. The material shall be vacuum or inert atmosphere melted to control metallurgical cleanliness and alloy chemistry. Bar, plate, and tubing shall be supplied as hot finished or cold finished and annealed or heat treated. Surface condition may be oxidized, descaled, pickled, blasted, machined, ground, mechanically polished, or electropolished. Major elements shall be analyzed by direct current plasma spectrometry, atomic absorption, inductively coupled plasma spectrometry, X-ray spectrometer, glow discharge mass spectrometry, or an equivalent method. Carbon shall be measured by combustion and hydrogen shall be measured by inert gas fusion or vacuum hot extraction. Nitrogen and oxygen shall be measured by inert gas fusion. The nickel and titanium contents of nickel-titanium shape memory alloys cannot be measured to a precision required to guarantee shape memory or superelastic properties. Calorimetry or an equivalent thermomechanical test method must be used to assure the alloy formulation in terms of transformation temperature. Mechanical properties of the samples such as tensile strength and elongation shall be determined after annealing.1.1 This specification covers the chemical, physical, mechanical, and metallurgical requirements for wrought nickel-titanium bar, flat rolled products, and tubes containing nominally 54.5- to 57.0-weight percent nickel and used for the manufacture of medical devices and surgical implants.1.2 Requirements are for mill product, measuring 5.50 to 94.0 mm [0.218 to 3.70 in.] in diameter or thickness. Mill product is not intended to have the final shape, final surface finish, or final properties of the medical device, implant, or their components. Finished NiTi cold-worked tube should be considered under Specification F2633.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.