. The Bell System technical journal . flexibility since a change in the size of wire can be ac-complished simply by increasing or reducing the number of dies were conducted to determine the gain by using heavier reduc-tions and annealing the wire before redrawing, and Fig. 17 shows theincreased reduction possible at the first die when the metal is this test, an annealed No. 22 gauge wire of 31 per cent elongation 208 BELL SYSTEM TECHNICAL JOURNAL was reduced to No. 24, two gauges, in one draw. The soft copper per-mitted a double reduction at the first die, but the elongat
. The Bell System technical journal . flexibility since a change in the size of wire can be ac-complished simply by increasing or reducing the number of dies were conducted to determine the gain by using heavier reduc-tions and annealing the wire before redrawing, and Fig. 17 shows theincreased reduction possible at the first die when the metal is this test, an annealed No. 22 gauge wire of 31 per cent elongation 208 BELL SYSTEM TECHNICAL JOURNAL was reduced to No. 24, two gauges, in one draw. The soft copper per-mitted a double reduction at the first die, but the elongation droppedduring the operation to less than 1 per cent; the second reduction onthis test was from No. 24 to No. 26 gauge and the pull required for thispass practically coincides with the breaking strength of the wire. Wiredrawing under such conditions is impractical because the annealingoperation is much more expensive than drawing hard wire from No. 22to No. 24 in two passes. 20 Lbs. 30^ 25% 15 Lbs. 10 5 Lbs. 5< O ^. 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Die Size1 2 3 4 5 6 7 8 9 to n 12 13 14 15 (6 (7 18 RtouciioN Fig. 18 Figure 18 illustrates the results obtained when drawing annealedwire with reductions. The large margin of safety betweenthe pull required and the breaking strength of the material again dis-appears after two reductions. Fig. 19 illustrates practical drawing Slight irregularities in the curves are clue to variations from the mean in thediameters of the dies used during the test. DEVELOPMENTS IN MANUFACTURE OF COPPER WIRE 209 conditions adopted for drawing wire to finished sizes without anneaUngduring the process. 20 Use. \5 Lbs. 10 Lbs. 5 Las
Size: 1312px × 1904px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
