Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
  • H01B1/026—Alloys based on copper
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B15/00—Obtaining copper
  • C22B15/0026—Pyrometallurgy
  • C22B15/006—Pyrometallurgy working up of molten copper, e.g. refining
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper

Definitions

• the present invention relates to a method for decreasing the softening temperature and improving the electrical conductivity of oxygen-free high conductivity copper.
• Oxygen-free copper of high conductivity differs from the oxygen containing (tough pitch) copper generally used as electrical conductors in that it possesses a greater toughness, a better weldability and a better hydrogen annealing resistance.
• its technical utility value generally is greater than that of the tough pitch copper.
• the softening temperature of this quality of copper however is higher than that of good tough pitch copper, in other Words, in order to get the material that has been worked into a hard condition to become soft again, a higher annealing temperature has to be used than with the tough pitch copper. Low softening temperature is required in some special cases such as when manufacturing magnet wires of small diameter, the temperature resistance of the coating enamel then restricting the permissible annealing temperature.
• Dissolved impurities in metal increase the softening temperature and decrease the electrical conductivity.
• Refining high conductivity copper is generally carried out electrolytically, so that the quantity of impurities can be kept fairly low.
• impurity viz sulphur
• the removal of which to the desired extent is particularly difficult in this connection, since the electrolyte being used in the refining process contains plenty of sulphur compounds (sulphuric acid, copper sulphate).
• the amounts of sulphur that remain in solid solution in the conventional copper treatment steps are very small, e.g. at 700 C. only about 10 grams per ton (0.001%) are dissolved, but still they have an essential influence particularly on the softening temperature.
• One way is to try to bring the sulphur, without reducing its content in the copper, into a form where its detrimental effects are eliminated.
• Another way specifically for decreasing the softening temperature is to facilitate the most difficult stage of the softening process, i.e. the beginning of the recrystallization. In principle this can be done e.g. by means of increasing the number of nucleation sites in the micro structure of the metal.
• the principle of the method according to the invention is that the dissolved sulphur contained in the copper is brought into an inefficient form by means of binding it with a suitable added ingredient and at the same time by utilizing the resulting precipitates as facilitating the recrystallization. It is of course required that the added ingredient must be such that its use does not have any detrimental elfect on other properties of the copper.
• lanthanides especially cerium or cerium-containing alloys can be utilized. It has been experimentally proved that the addition of a lanthanide element such as cerium or its alloys decreases the softening temperature of oxygen-free cop per by an amount ranging from 50 to C. and at the same time stabilizes the properties of the copper so that both the softening temperature and the electrical conductivity become in practical conditions independent of the heat treatment preceding the cold working step and of the hot working temperature.
• a preferred cerium content is in the range from 2 to 500 grams per ton (from 0.002 to 0.05%) depending on the purity of the basis material and on the intended application.
• the alloys melted by means of a vacuum induction furnace. The charges were about 25 kilograms.
• the cerium was added as a master alloy (5% of Jcerium).
• the molten material was cast in a water cooled chill mould. The ingots were machined into 97 mm. diameter billets, which subsequently were hot extruded into 18 mm. diameter rods. Next followed drawing to 5.7 mm. diameter and finally (softening) annealing at 500 C. for 2 hours.
• the bending values meet requirements set upon oxygen-free copper.
• a method of decreasing the softening temperature and improving the electrical conductivity of high conductivity oxygen free copper having sulphur in ordinary amounts comprising the steps of reducing oxygen copper to the molten state, adding a lanthanide element to the molten copper in an amount equal by weight to about four times the amount of sulphur originally present, and solidifying the resultant molten mass.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Conductive Materials (AREA)
• Manufacture And Refinement Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8505221

Family Applications (1)

Country Status (8)

Cited By (5)

Citations (2)

• 1966
  • 1966-05-04 FI FI1175/66A patent/FI40237B/fi active
• 1967
  • 1967-05-01 US US634911A patent/US3525605A/en not_active Expired - Lifetime
  • 1967-05-03 YU YU0886/67A patent/YU31437B/xx unknown
  • 1967-05-03 BE BE697951D patent/BE697951A/xx unknown
  • 1967-05-03 CH CH627267A patent/CH503113A/de not_active IP Right Cessation
  • 1967-05-03 GB GB20616/67A patent/GB1137809A/en not_active Expired
  • 1967-05-03 SE SE06309/67A patent/SE337483B/xx unknown
  • 1967-05-04 JP JP42028585A patent/JPS494127B1/ja active Pending

Patent Citations (2)

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