ASTM F204-76(2013)
(Test Method)Standard Test Method for Surface Flaws in Tungsten Seal Rod and Wire
Standard Test Method for Surface Flaws in Tungsten Seal Rod and Wire
ABSTRACT
This test method establishes the apparatuses to be used, specimen preparation methods, and standard procedures for determining the presence of surface flaws in tungsten-seal rods and wires of random or cut lengths, and in the tungsten section of multiple-piece-through leads used in electronic devices, by means of examination of a glass bead sealed to the tungsten.
SCOPE
1.1 This test method covers the determination of the presence of surface flaws in tungsten-seal rod and wire of random or cut lengths, and in the tungsten section of multiple-piece-through leads used in electronic devices, by means of examination of a glass bead sealed to the tungsten.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: F204 − 76 (Reapproved 2013)
Standard Test Method for
Surface Flaws in Tungsten Seal Rod and Wire
ThisstandardisissuedunderthefixeddesignationF204;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.3 Light Source— A suitable white light source, preferably
diffuse for illumination of the bead under the microscope.
1.1 This test method covers the determination of the pres-
ence of surface flaws in tungsten-seal rod and wire of random
4. Preparation of Test Specimen
or cut lengths, and in the tungsten section of multiple-piece-
through leads used in electronic devices, by means of exami-
4.1 The test specimen shall be a beaded tungsten rod
nation of a glass bead sealed to the tungsten.
prepared in the following manner:
4.1.1 Clean the surface to be beaded in the usual manner
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this employed by the user of the tungsten.
standard. 4.1.2 Alternative Methods of Specimen Preparation—In
case of disagreement between the manufacturer and the
1.3 This standard does not purport to address all of the
purchaser, substitute one of the following alternative methods
safety concerns, if any, associated with its use. It is the
of preparing the tungsten rod for that in 4.1.1.
responsibility of the user of this standard to establish appro-
4.1.2.1 Boilthetungstenfor2minina5 %solutionof27 %
priate safety and health practices and determine the applica-
hydrogen peroxide. Pour off the hydrogen peroxide and rinse
bility of regulatory limitations prior to use.
the tungsten twice in distilled water. Dry rapidly with pure
2. Terminology
alcohol or in an oven heated to 100°C.
2.1 Definitions: 4.1.2.2 Place the tungsten in a solution (20 weight %) of
2.1.1 beaded length—the actual length through which a
sodium hydroxide or potassium hydroxide and pass sufficient
glass-to-tungsten seal exists as evidenced by the color of the electrical current through it to induce electrolytic action
interface. sufficient to clean the specimen.
2.1.2 fault—a tungsten-glass seal in which a fissure, either
4.2 Bead the cleaned tungsten rod over the area to be
delineated by a line of bubbles or in itself clearly discernible,
examined with glass, of the type and wall thickness commonly
is observed when inspected as prescribed in this test method.
used for beading, to a length of not less than 5 mm bead length.
2.1.3 fissure—any narrow opening or cleft in the surface of
4.3 To permit examination of the glass-tungsten interface,
the tungsten.
the bead shall be substantially free from bubbles, from causes
2.1.4 line of bubbles—one long or several small bubbles so
otherthanthetungstendefects,andshallhavebeensoprepared
arranged in the otherwise substantially bubble-free glass bead
that the surface of the tungsten is clearly visible through the
that they are in an almost straight line immediately
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