TT-B-1325D
4.3 Test procedure. The beads shall be tested in accordance with the methods specified in Table II and as otherwise specified herein to determine compliance with the requirements of section 3. Unless otherwise specified all tests shall be conducted at conditions specified in Section 9 of FED-STD-141. All test reports shall contain the individual values used in expressing the final results. Failure to pass any tests, or noncompliance with any requirement, shall be cause for rejection of the sample.
Table II. Tests and methods.
Characteristics |
Requirement Paragraph |
ASTM Method |
Test Method Paragraph |
Appearance |
3.2.1 |
-- |
4.3.1 |
Roundness |
3.2.2 |
D 1155 |
4.3.2 |
Index of refraction |
3.2.3 |
-- |
4.3.3 |
Specific gravity |
3.2.4 |
-- |
4.3.4 |
Gradation |
3.2.5 |
D 1214 |
4.3.5 |
Resistance to acid |
3.2.6 |
-- |
4.3.6 |
Resistance to calcium chloride |
3.2.7 |
-- |
4.3.7 |
Resistance to sodium sulfide |
3.2.8 |
-- |
4.3.8 |
Water resistance |
3.2.9 |
-- |
4.3.9 |
TT-B-1325D
4.3.1 Appearance. Spread thinly 10 g of sample on white bond paper and examine visually for compliance with 3.2.1.
4.3.2 Roundness. The roundness of the Type I and Type III beads shall be determined in accordance with ASTM method D 1155. Use Procedure A for Type III beads and Procedure B for Type I beads. The roundness of the Type IV beads shall be determined in accordance with FlH Designation T 520-93. Evaluate for compliance with the requirements in 3.2.2.
4.3.3 Index of refraction. The index of refraction shall be determined by the immersion method. A microscope capable of a minimum of 100x magnification, equipped with a light source and certified immersion oils shall be used. Place crushed beads on a microscope slide and immerse in a refractive index immersion oil at
standard conditions. (The immersion oil shall have a refractive index within 0.02 units of that of the beads to be tested.) Cover with a microscope slide and determine the refractive index of the beads to the nearest one-hundredth of a unit. Evaluate for compliance with the requirements of 3.2.3.
4.3.4 Specific gravity. Place 100 g of the beads in an oven at 105°C ± 2°C and dry to constant weight. Remove the beads and place in a desiccator until the sample is cool. Remove 60 g of beads from the desiccator and weigh the sample accurately. Pour the beads slowly into a 100 ml graduated cylinder containing 50 ml of reagent- grade xylene. Make certain that air is not entrapped among the beads. Calculate the specific gravity as follows:
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