This specification covers three types of drawn pure and thoriated tungsten wire suitable for fabrication into parts for electron tubes, lamps, and other electron devices, and one type of rod for metal-to-glass sealing (grid wire is excepted): Type 1A, Type 1B, Type 2A, and Type 2B. Types 1A and 1B are designated as UNS R07005; Type 2A is designated as UNS R07911; and Type 2B is designated as UNS R07912. The wire and rod shall conform to the prescribed chemical requirements for thoria and tungsten and to the specified physical properties such as tensile strength, ductility, and surface defects. The weight/diameter conversion formulas are given. Wires shall be furnished in the following specified finishes: Finish 1, Finish 2, Finish 3, Finish 4, Finish 5, Finish 6, and Finish 7. The material shall be smooth, free of twists, bends, kinks, curls, and as free of dents, swaging marks, scratches, die marks, laps, seams, splits, slivers, inclusions, bumps, pits, grooves, cracks, and other physical defects Unless black finish is specified, all types of wire shall have a clean finish, free of graphite, grease, oil, and lubricants. Wire for hooks, supports, springs, anchors, and mesh shall have a bright smooth surface free of cracks holes, or craters. The requirements for straightness, and coiling and spooling are detailed as well. The following analysis and tests shall be performed: chemical analysis, tensile test, ductility test, visual inspection, dimensional measurements, and examination for surface flaws.

1.1 This specification covers three types of drawn wire suitable for fabrication into parts for electron tubes, lamps, and other devices; and one type of rod for metal-to-glass sealing (grid wire is excepted):

1.1.1 Type 1A—Commercially pure nonsag wire (Note 2 and Note 3).

1.1.2 Type 1B—Commercially pure rod suitable for metal-to-glass sealing.

1.1.3 Type 2A—Thoriated filament wire containing 1 % thoria.

1.1.4 Type 2B—Thoriated filament wire containing 2 % thoria.

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.3 Types 1A and 1B are designated as UNS R07005. Type 2A is designated as UNS R07911. Type 2B is designated as UNS R07912.

1.4 The following precautionary caveat pertains only to the Chemical Analysis, Section 12 of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

Note 1: A dimensional measurement method for testing nonsag tungsten wire above 0.030 in. (0.76 mm) in diameter is provided in Test Method F269.

Note 2: Acceptance of nonsag wire characteristics for particular applications of size shall be by agreement between producer and consumer based on either a flashed microstructure as shown by photomicrographs, or on dimensional measurement limits determined in accordance with Test Method F269.

1.5 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.