ASTM-B415:16(R2021) pdf free download – Standard Specification for Hard-Drawn Aluminum-Clad Steel Wire.
7. Dimensions and Permissible Variations
7.1 The size shall he expressed by the wire diameter in decimal fractions of an inch to the nearest 0.0001 in. (0.0025 mm), that is, in tenths of mils.
7.2 Within the range of diameters included in Table 3, the wire shall not vary from the specified diameter by more than the amounts shown in this table. In computing permissible variations, diameters shall he rounded to the nearest 0.0001 in. (0.0025 mm).
7.3 If accessible, one diameter measurement shall be taken near each end and one near the middle of the coil or reel. In the case of reels, the center and one end may not be accessible and the prescribed diameter measurement shall be taken along the length of the accessible material, if any of the selected coils or reels fail to conform to the requirements for diameter as prescribed in 7.2, all coils or reels shall be measured in the manner specified.
8. Thickness of Aluminum
8. 1 The aluminum thickness at any point shall he not less than stated in Table 4. Measurements shall he read to the closest 0.001 in. (0.025 mm). In determining the required or measured thickness. 0.0005 in. (0.013 mm) or less shall be dropped. For greater than 0.0005 in., the next larger 0.001 in. shall be used. Measurements shall be made by (a) using suitable electrical indicating instruments operating on the permeameter principle, or (b) direct measurement. For referee purposes, direct measurement shall be used to determine aluminum thickness on specimens taken from the ends of the coils.
9. Twist Test
9. 1 The wire shall withstand without fracture not less than
20 twists in a length equivalent to 100 limes the nominal diameter of the wire. In this test the specimen shall be gripped at its ends in vises, one of which shall be free to move longitudinally during the test. A small tensile load of approximately 15 lb (67 N) shall be applied to the specimen during testing. The specimen shall be twisted by rotating one of the vises at a rate of approximately 15 twists per minute in the same direction until fracture occurs. The number of twists shall he indicated by a counter or other suitable device.
9.2 Specimens after twisting to destruction shall not reveal any seams. pits. slivers, or surface imperfections of sufficient magnitude to indicate inherent defects or imperfections in the wire. Examination of the wire at the break shall show no separation of the aluminum from the steel.