Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/02—Contacts characterised by the material thereof
  • H01H1/021—Composite material
  • H01H1/025—Composite material having copper as the basic material
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/10—Handling in a vacuum
• • 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
  • C22C1/00—Making non-ferrous alloys
  • C22C1/02—Making non-ferrous alloys by melting
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/02—Contacts characterised by the material thereof
  • H01H1/0203—Contacts characterised by the material thereof specially adapted for vacuum switches
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/4998—Combined manufacture including applying or shaping of fluent material
  • Y10T29/49988—Metal casting
  • Y10T29/49989—Followed by cutting or removing material

Definitions

• This invention relates to the production of alloys for use in the contacts of vacuum switches.
• the alloy should have the following properties:
• a billet of O.F.H.C. (oxygen free, high conductivity) copper together with the required amount of high purity iron is placed in a previously degassed graphite crucible. If the iron were allowed to come into contact with the graphite crucible, before alloying with the copper, it would react with the graphite, causing damage to the crucible inside Wall and resulting in undue carbon pick-up in the melt. To prevent such contact, the iron is placed in a hole drilled in the copper billet. Using this method, no significant reaction occurs. The crucible is placed in a high frequency cvacuable furnace. To deoxidise the metal to the required low level of the order of 0.1 ppm. it is heated to 1350 C.
• O.F.H.C. oxygen free, high conductivity
• the temperature is then reduced to 1200 C. whilst the furnace is evacuated to a pressure of about mm. Hg, to degas the molten metal.
• the metal is then solidified progressively from the bottom upwards by slowly raising the induction heating coil. This method of solidification produces a pipe-free ingot and facilitates the removal of any gas which may remain in the molten metal.
• the graphite crucible wall is made sufliciently thin to be penetrated by the RF. field so that electromagnetic stirring of the molten metal is obtained.
• the fingers of a split contrate contact are stressed in bending, and the properties of alloys for this purpose were compared by loading small cantilever strips of the materials.
• the alloy samples are annealed at 700 C. for 2 hours and slowly cooled. After this treatment, the
• alloy of copper with 2% iron has an electrical conductivity of 55% IACS.
• the load required to give 0.020 deflection of the 2% iron alloy was 28 /2 lbs. compared with 13 lbs. for the 99% copper-1% silver alloy.
• the elastic springback from the 0.020 deflection was considerably higher for the copper alloy containing 2% iron, i.e., 0.011" compared with 0.005" for the copper alloy containing 1% silver.
• a pair of split-contrate switch contacts were made in the usual manner from a copper-2% iron alloy casting, to give a finger length of 1 /2".
• the machined contacts were annealed at 700 C. for two hours and allowed to cool slowly.
• the contacts were placed in a mechanical test rig with their fingers in juxtaposition as in normal use. A load of 1000 lbs. was applied to the pair of contacts and the amount of spring-back of the fingers was noted as the load was released.
• Spring-back commenced when the load has been reduced to 300 lbs. and proceeded almost linearly down to zero load.
• the total amount of spring-back was between 0.016" and 0.020", i.e., 0.008" to 0.010" for each contact. Satisfactory contact was thus maintained between all opposing pairs of fingers.
• a method of manufacturing a contact for an electric vacuum switch which comprises providing a charge consisting essentially of 95 to 99% by weight copper and 5 to 1% by weight high purity iron in a previously degassed graphite crucible; heating the said charge in a furnace at a temperature of about 1350 C. in an atmosphere of hydrogen for about one hour to form a homogeneous melt; degassing the molten metal by reducing the temperature of the melt to about 1200 C. while evacuating the furnace to a pressure of about 10 mm. Hg; solidifying the melt to form an alloy body; and forming a contact from the alloy body in the cast state by machining.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Composite Materials (AREA)
• High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
• Contacts (AREA)
• Manufacture And Refinement Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10178843

Family Applications (1)

Country Status (6)

Families Citing this family (1)

Citations (15)

• 1965
  • 1965-05-26 GB GB22405/65A patent/GB1129152A/en not_active Expired
• 1966
  • 1966-05-18 US US550901A patent/US3488833A/en not_active Expired - Lifetime
  • 1966-05-23 DE DE19661533157 patent/DE1533157A1/de active Pending
  • 1966-05-24 CH CH746066A patent/CH495620A/de not_active IP Right Cessation
  • 1966-05-25 NL NL6607198A patent/NL6607198A/xx unknown
  • 1966-05-26 BE BE681664D patent/BE681664A/xx unknown

Patent Citations (15)

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