Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/003—Alloys based on aluminium containing at least 2.6% of one or more of the elements: tin, lead, antimony, bismuth, cadmium, and titanium

Definitions

• ABSTRACT annealed, a minimum conductivity of 54% lACS and when annealed and then cold drawn, a minimum conductivity of 58% lACS.
• This invention relates to aluminium alloys for electrical conductor, particularly Al-(Sb'Mg) alloys, having improved strength and elongation in hardened, semihardened and softened conditions without substantial lowering of electrical conductivity as compared with conventional aluminium alloys for electrical conductor.
• aluminium alloys for electrical conductor such as ASTM 6201 alloy'(Al-Mg-Si alloys) and ASTM 5005 alloy (Al-Mg alloy) have been used for most of the aluminium conductors in aerial power transmission lines, and particularly aluminium alloys for electrical conductor, inspite of their poor strength, have been used extensively as aluminium conductor steel reinforced (ACSR) because of their excellent electrical conductivity.
• the conventional 6201 alloy is an agehardening alloy and requires a special manufacturing process combining an age-hardening heat treatment of solution-heating, quenching and tempering with cold wire drawing to give work-hardening effects, so that its production cost is very high. Therefore, inspite of its good properties such as the electrical conductivity of about 52% lACS and the tensile strength of about 32kg/mm the alloy has been used only for special applications and scarcely used for the all-aluminium-alloy stranded cable replacing the aluminium conductor steel reinforced.
• 5005 alloy is a typical solid solution alloy which is non-hardenable by heat treatment, and can be strengthened only by work hardening through cold wire drawing so that inspite of its lower tensile strength of about 24kg/mm (electrical conductivity of about 53% lACS) as compared with 6201 alloy, the advantage of non-heat treatment and therefore low production cost more than makes up for the disadvantage of lower tensile strength and permits the alloy to be commercially used as all-aluminium-alloy stranded cable.
• aluminium conductors used in communication systems, indoor wirings, coiling, etc. require good tensile strength, elongation and electric conductivity combined-with good workability into fine wire.
• Al-Sb binary alloy nothing has been known except its equilibrium phase diagram, and there has been no information about its electrical and mechanical properties.
• the present inventors studied the Al-Sb binary alloy, but could not improve the properties of aluminium by the antimony solid soluble in aluminium, or by the intermetallic compound formed between aluminium and antimony. Then the.present inventors fully reviewed the effects of various third elements on the Al-Sb alloy and have found that in case of Al-Sb-Mg alloys obtained by addition of suitable amount of magnesium into the Al-Sb alloy, antimony and magnesium produce an intermetallic compound in aluminium in a uniform dispersion in the matrix, and remarkably improve the mechanical properties of the alloy without substantially lowering the electric conductivity, and thus the present inventors have developed an aluminium alloy for electrical conductor excellent in strength and elongation in hardened, semi-hardened and softened conditions.
• one of the objects of the present invention is to provide a novel aluminium alloy for electrical conductor having improved properties (conductivity, strength and ductility) whether in hardened, semihardened or softened conditions, over the conventional aluminium for electrical conductor and aluminium alloys.
• object of the present invention is to provide an aluminium alloy for electrical conductor having similar electric conductivity and better strength in a hardened condition than the conventional 5005 alloy, or having similar strength and better electric conductivity than 5005 alloy.
• Further object of the present invention is to provide an aluminium alloy for electrical conductor which shows improved strength and ductility without substantially lowering electric conductivity in semi-hardened or softened condition as compared with the conventional semi-hardened or softened aluminium for electrical conductor.
• the alloys of the present invention comprise pure aluminium with addition of 0.01 0.6% by weight (hereinafter expressed by for short) antimony, 0.05 0.6% magnesium, and further addition of up to 0.4% by weight copper and up to 0.7% of one or more elements (including those deriving from impurities usually contained in aluminium) whose binding-energy with antimony or magnesium is less than that between antimony and magnesium, so as to obtain an aluminium alloy for electrical conductor having similar electric conductivity and better strength in a hardened condition than the conventional 5005 alloy or having similar strength and better electric conductivity than 5005 alloy, or an aluminium alloy for electrical conductor having better strength and elongation, without sacrifice of electric conductivity, in a semi-hardened or softened condition, than the semi-hardened or softened aluminium for electrical conductor.
• the reason for limiting the antimony content and the magnesium content to 0.01 0.6% and 0.05 0.6% respectively in the alloys of the present invention is that in case antimony content is less than 0.01% or magnesium content is less than 0.05%, the amount of compounds between antimony and magnesium is not enough for improving the properties of the alloy, while in case antimony content or magnesium content is more than 0.6%, the fluidity of molten metal will be lowered, making it difficult to obtain sound cast ingots.
• excess of the antimony content will not only lower remarkably the workability of the alloy, but also increase the size of compounds formed between antimony and magnesium, thus weakening the strength improvement effect, while excess of the magnesium content will increase the amount of soluble magnesium, thus remarkably lowering the electric conductivity.
• antimony and magnesium are not stated by percentage in equivalent of compound because excess antimony or magnesium is not harmful, and causes no problem for commercial use as far as they are within the above ranges of composition.
• the reason for adding up to 0.4% by weight of copper and up to 0.7% by weight of one or more elements such as iron, nickel, manganese, tellurium, whose binding energy with antimony or magnesium is less than that between antimony and magnesium, is that even when one or more of these elements are contained, compounds between antimony and magnesium are formed in the aluminium alloy, and the properties of the aluminium alloy may be further improved by addition of these elements, but more than 0.7% by weight of these elements will lower electric conductivity, corrosion resistance and workability of the alloy, thus prohibiting commercial use of the alloy as electro conductive material. Although all of the elements whose binding energy with antimony or magnesium is less than that between antimony and magnesium will give almost similar effects when they are contained in the alloy, it is most effective to add copper or iron or both.
• elements such as iron, nickel, manganese, tellurium
• the alloys of the present invention similar strength to and better electric conductivity than the conventional 5005 alloy, or similar electric conductivity to and better strength than 5005 alloy, it is desirable that one or more elements whose binding energy with antimony or magnesium is less than that between antimony and magnesium are contained in 0.05 0.6% for each element and in 0.05 0.6% in total.
• iron whose binding energy with antimony or magnesium is less than that between antimony and magnesium is contained in a range of0.05 0.6%, more preferably 0.05 0.5%, and for copper, up to 0.4% and for both, 0.05 0.5% in total.
• aluminium metal used in the present invention commercially available aluminium ingot may be used, but it is preferable to use aluminium of more than 99.5% purity.
• alloys of the present invention may be produced by entirely the same method as the conventional aluminium for electrical conductor or 5005 alloy.
• antimony is added to a molten metal of aluminium, binary alloys such as Al-Fe, Al-Cu, or trinary alloys such as Al-Cu-Fe, then magnesium is added to the molten alloys.
• the molten alloy is subjected to wire rod making by a continuous casting and rolling method using rotary moulds, or ingots obtained by casting with water cooling is pre-heated and may be easily worked down to wire rod either through hot rolling by a wire rolling mill or through hot extrusion by an extrusion press.
• the wire rod thus obtained is subjected to cold drawing on a high-speed continuous drawing machine down to required size of hardened electric conductor suitable for overhead power transmission and distribution lines.
• the above obtained hard conductor can be converted by annealing at a temperature between 500 C into semi-hard or soft aluminium alloy conductor suitable for communication systems, indoor wirings, and coilings.
• the above annealing temperature between l50 500 C is selected for the reason that if the annealing is done below 150 C, elongation necessary for a semi-hard or soft conductor can not be obtained and no improvement of electric conductivity can be seen whatever working ratio is taken, while above 500 C grains will excessively grow in size, thus lowering elongation and flexibility and increasing variation in quality.
• the above hard conductor can be converted into a still better semi-hard aluminium alloy conductor by annealing it and then cold drawing it down to less than 50%.
• the alloys of the present invention when made into hard conductor, completely eliminate such a series of agehardening heat treatments combined with workings as required for production of the conventional 6201 alloy, and can be produced as easily as or more easily than 5005 alloy. And the alloys can also easily be made into semi-hard or soft conductor, because it has much wider range of annealing temperature than any conventional aluminium alloy for electrical conductor.
• EXAMPLE 1 The wires of the present invention and other wires (for comparison), respectively, having the compositions set forth in Table l were cast with water cooling into bar ingots of 4 inches X 4 inches size by an ordinary melting and casting method, and the ingots thus obtained were hot rolled at 450 C on a wire rolling maparative alloy No. l) with only lowered conductivity; thus these alloys are not improved in respect of properties as a conducte r wire.
• the comparative Al-Mg alloy of No. 4 shows some improvement in tensile strength but shows considerably lowered conductivity. From the relation between the conductivity and the tensile strength, this alloy is not advantageous as compared with conventional conductor wires.
• Al-Sb alloys Al and Sb is dissolved in aluminium or Al and Sb form an intermetallic compound, improvement of strength of aluminium can not be obtained, and in case of Al-Mg alloys, Mn dissolved in aluminium improves tensile strength slightly, but lowers conductivity considerably.
• the intermetallic compound of Mg and Sb uniformly dispersed in the aluminium matrix improves tensile strength, and the reduced amount of dissolved Mg and Sb improves conductivity.
• tensile strength can be improved without lowering conductivity and ductility by adding an element, such as Fe, having lower binding energy than the binding energy of the intermetallic compound of Sb and Mg in addition to the appropriate amounts of Sb and Mg.
• an element such as Fe
• an appropriate amount of Cu and Mg is present, if Sb content is too much as in the comparative alloy, No. 26, or if Cu and Sb are more than the composition range of the present invention, the alloy can not be used as a conductor wire.
• the present inventive conductor 1 wire contains an appropriate amount of Mg and Sb which must be uniformly dispersed as intermetallic compound in aluminium, and for this reason the amount of Mg and Sb, and the amount of the element such as Fe and Cu which have lower energy than the binding energy of Mg and Sb should not exceed a certain amount.
• the conventional alloy of 5005 can be improved remarkably by the present invention in conductivity or tensile strength, and can be used widely as conductors such as steel-cored aluminium alloy wires, aluminium alloy wire strands.
• wire rods produced similarly as in Example 1 are cold drawn to possible minimum diameters, and the number of wire breaks during the drawings are shown inTable 3.
• the drawing conditions are just same as in case of ECAL.
• Mg, Fe and Sb should be restricted less than 0.6 wt.%, 0.7 wt.% and 0.6 wt.% respectively, and the total amount of Fe and Cu must be restricted less than 0.7 wt.%. Otherwise, as in case of the comparative alloy of No. 32, only poor drawability is obtained.
• the present inventive conductor wires have drawability equal to that of the conventional ECAL and 5005 alloys.
• EXAMPLE 3 The wires of the present invention 3, l0, 10, 22, 26, and 29 and comparative wires 1, 4, 6, 7, l3 and 32 set forth in Table l were cast and hot-rolled into wire rods, 8mm in diameter, by the same method as in Example 1, and they were cold-worked at the reduction rate of 99% and annealed for hours at various temperatures stated in Table 4 obtain semi-hard and soft wires. Their tensile strength and electric conductivity at C were measured, and the result are shown in Table 4.
• the annealing temperature range must be restricted so that variations in properties become very large.
• strength equal to that of E.CAl semi-hard alloy can be obtained with full annealing so that the production is very simple and easy and stability in property and quality can be obtained.
• Semi-hard grades of the present inventive alloys have tensile strength equal to that of hardened E.CAl alloy and show excellent ductility, and thus very useful for coilings, communication wires and so on. The reason why such excellent properties can be attained is that an appropriate amount of intermetallic compound of Mg and Sb is dispersed in aluminium.
• EXAMPLE 4 Wire rods of the wires of the present invention 3, 8, l3, 17, 20, 24 and 30 and comparative wires 1, 7 and 23 of Table l were produced by the same method as in Example 1, and cold drawn at the reduction rate of more than 89%, and they were then annealed at about 300 7 C, and again cold-drawn at varying reduction rates of 10%, 20%, 40% and to obtain semi-hard wires.
• the present inventive alloy can be converted into semi-hard wires by annealing and cold working, and thus obtained semi-hard wires have excellent properties unexpectable from the semi-hard wires-of conventional conductor aluminium.
• the reason why the present inventive conductor wires have such excellent properties is that an appropriate amount of the intermetallic compound of Mg and Sb is uniformly dispersed, which has thermal stability and increases work hardening ability. Therefore, in case of Cu addition, when Cu should not be added in an amount more than 0.4 wt.%, otherwise an intermediate phase or a stabilized phase of Cu hinders the uniform dispersion of Mg.Sb compound.
• the excellent properties of the present inventive conductor wires cannot be obtained by a binary alloy such as Al-Sb alloy, Al-Mg alloy, Al-Fe alloy and Al-Cu alloy, a ternary alloy such as Al-Sb-Fe alloy, Al-Sb-Cu alloy, Al-Mg-Fe alloy and Al-Mg-Cu alloy and by an alloy such as Al- Mg-Fe-Cu and Al-Sb-Fe-Cu.
• a binary alloy such as Al-Sb alloy, Al-Mg alloy, Al-Fe alloy and Al-Cu alloy
• a ternary alloy such as Al-Sb-Fe alloy, Al-Sb-Cu alloy, Al-Mg-Fe alloy and Al-Mg-Cu alloy
• an alloy such as Al- Mg-Fe-Cu and Al-Sb-Fe-Cu.
• intermetallic compound of Mg and Sb is present in aluminium, and excellent properties as conductor wire such as conductivity, tensile strength, elongation, bending property and drawability are obtained only when the amount of Mg and Sb and the amount of Cu and Fe are specifically restricted.
• the conductor wire of the present invention is useful for various kinds of overhead conductors in the form of hard wire, and useful for various conductors such as for communication, indoor wirings and ceilings in the form of semi-hard and soft grades which are obtained by annealing alone or annealing cold drawing the hard wires.
• An aluminum alloy conductor wire consisting essentially of about 0.01 0.6% by weight antimony, about 0.05 0.6% by weight magnesium, less than 0.4% by weight copper and less than 0.7% by weight of a member selected from the group consisting of iron, nickel and manganese, the balance being aluminum and unavoidable impurities thereof, a part of the antimony and magnesium forming an intermetallic compound, said compound being uniformly dispersed in an aluminum matrix, the alloy wire having, when cold drawn and not annealed, a minimum conductivity of 54% lACS and when annealed and then cold drawn, a minimum conductivity of 58% IACS.
• An aluminum conductor wire according to claim 1 which contains 0.05 to 0.45 weight percent antimony, 0.1 to 0.6% magnesium and 0.05 to 0.4% copper.
• An aluminum conductor wire according to claim 1 which contains 0.15 to 0.6% iron.

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• 1969
  • 1969-06-05 FR FR6918567A patent/FR2011017B1/fr not_active Expired
  • 1969-06-06 DE DE1928603A patent/DE1928603C2/de not_active Expired
  • 1969-06-06 GB GB28688/69A patent/GB1206907A/en not_active Expired
• 1971
  • 1971-12-15 US US00208444A patent/US3773501A/en not_active Expired - Lifetime

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