| 摘要 |
<p>1469916 Electric cables SOUTHWIRE CO 1 Aug 1975 [1 Aug 1974 (3)] 32301/75 Heading H1A [Also in Division C7] An electrical conductor for an overhead power wire comprises a steel core and an at least partially annealed aluminium alloy covering having an electrical conductivity of at least 61% IACS and a yield strength of 13,000 p.s.i. for an elongation of 5% when partially annealed and at least 8,500 p.s.i. for an elongation of 15% when fully annealed, wherein the aluminium alloy component acts as a load-carrying element when the conductor is strung between supports and tensioned in excess of 8500 p.s.i. Suitable aluminium alloys contain between 97À00 at 99À50 weight per cent A1, the preferred alloying elements being (i) Fe and Si, (ii) Co, Fe and Mg, (iii) Ni and Fe, with from 0À1 to 1À5% additional alloying elements selected from Mg, Co, Cu, Si, Zr, Nb, Ta, Y, Se, Th, C and rare earth metals. Mg may alternatively be excluded from (ii). The aluminium alloy may be in the form of circular or other cross-section wires wound on the core, or it may be an extruded sheath, or it may be a sheath obtained by wrapping a broad strip around the core and welding together the formerly laterally opposite edges. A preferred form of the Fe/Si alloy contains particles of iron aluminate of less than 2000 Š measured normal to the longitudinal axes of said particles, and a preferred form of the Co/Fe/ Mg alloy contains cobalt aluminate inclusions smaller than 2 microns long and ¢ micron wide.</p> |
