Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C1/00—Manufacture of metal sheets, metal wire, metal rods, metal tubes by drawing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C9/00—Cooling, heating or lubricating drawing material
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires

Definitions

• This invention relates to a method of producing wire. More particularly, it relates to an improvement in the process of drawing wire through one or more dies to mechanically work it to a desired final diameter.
• the die lubricant is applied.
• the lubricant is in the form of an aqueous suspension or emulsion containing colloidal graphite, and the application is accomplished by passing the wire through a bath of the lubricant composition.
• the graphite which adheres to the wire forms a protective coating for protection of the wire from further oxidation when it is heated to the temperature required for reduction in diameter in the next die in the series.
• the graphite coating is baked on the surface so that it will adhere sufficiently to afford the necessary lubricating action as the wire moves through the die.
• the method of drawing wire as described above has been open to a number of objections which stem primarily from the necessity for heating the wire to produce the oxide coating.
• the oxide coating is non-uniform which, in turn, causes a non-uniform coating of the subsequently applied lubricant.
• substantial die wear is experienced, and the wire may exhibit non-uniform diameter and physical properties.
• the additional heating step causes loss of valuable material. Part of this loss is attributable to the excessive oxidation found to be necessary to insure at least a minimum continuous oxide coating. Additional loss of material results from volatilization of the ingredients of the wire or oxides of the ingredients at the oxidation temperature.
• a still further object of the invention is to provide a method of drawing wire which involves substantially less die wear than has been experienced in wire drawing methods heretofore employed.
• the thickness of the oxide layer may be readily controlled by varying the length and rate of passage of the wire through the oxidizing solution and the concentration of the oxidizing agent in the solution. Furthermore, an uninterrupted oxide coating is obtainable even though only a thin layer of the oxide is applied. Since the wire is not subjected to any thermal extremes until after the lubricant is applied in the subsequent operation, there is a minimum of tendency for the oxide to flake off, exposing bare metal to which the lubricant will not adhere.
• the wire After the wire passes from the bath of the oxidizing solution, it may be passed directly to a station at which the lubricant is applied.
• the lubricant is colloidal graphite in an aqueous medium.
• the wire may be passed through a spray or bath of water to remove the by-products of the oxidation of the wire prior to application of the layer of lubricant material.
• the wire After the wire has received a coating of lubricant it passes continuously through a heating zone and is heated to whatever elevated temperature is required for work ing during passage through the reducing die. As indicated above, in connection with the description of the wire drawing processes heretofore employed, no appreciable oxidation of the wire occurs during this heating op e-ration since the surface of the wire is protected by,the lubricant layer.
• tungsten wire of 1.565 mils diameter was reduced to wire of 1.420 mils diameter in the manner described below.
• Tungsten wire of 1.565 mils diameter was continuously drawn from a supply spool and was passed through a bath containing an aqueous potassium permanganate solution of approximately 0.1 Normal concentration.
• the wire was drawn through the bath at a rate of about feet per minute and about 24 inches of the path of movement of the wire was below the surface of the bath, so'
• the wire was next passed through a bath of an aqueous emulsion containing colloidal graphite.
• This particular lubricant material is generally available on the market under the trade name Aquadag. Examinaton of the wire leaving the lubricant bath indicated that the surface was uniformly wet by a continuous film of the lubricant.
• the coated wire next was passed through a gas flame and was rapidly heated to a temperature of about 800 C. as measured by an optical pyrometer. At this temperature, the graphite coating was rapidly dried and baked on the wire surface to produce an adherent graphite film, and the wire was immediately drawn through a reducing die designed to work the diameter of the wire down to the desired dimension of 1.42 mils. Examination of the resulting Wire showed it to be of uniform cross-section O and free of flattened sections heretofore frequently characteristic of wire drawn by processes in which the oxide coating used as a base for the layer of lubricant was applied by heating the wire to an elevated temperature in air.
• the method of mechanically working metal wire to a desired diameter which comprises the steps of contacting the wire with an aqueous oxidizing solution capable of oxidizing the metal of the wire to a metal oxide insoluble in the solution, thereby forming on the wire an adherent layer of the metal oxide; applying a coating of a die lubricant over the oxide layer on the wire; heating the wire to working temperature; and thereafter drawing the wire through a reducing die.
• the method of mechanically working metal wire to a desired diameter which comprises the step of passing the wire through an aqueous oxidizing solution capable of oxidizing the metal of the wire to a metal oxide insoluble in the solution, thereby forming on the wire an adherent layer of the metal oxide; water-rinsing the wire to remove by-products of the oxidation of the metal of the wire by the oxidizing solution; passing the wire through an aqueous suspension of die lubricant; heating the wire to working temperature; and thereafter drawing the wire through a reducing die.
• the method of mechanically working tungsten wire to a desired diameter which comprises the steps of contacting the wire with an aqueous solution of potassium permanganate to form on the wire an adherent layer of tungsten oxide; applying a coating of graphite over the oxide layer; heating the wire to working temperature; and thereafter drawing the wire through a reducing die.
• the method of mechanically working tungsten wire to a desired diameter which comprises the steps of passing the wire through an aqueous potassium permanganate solution of 0.1 Normal concentration to form on the wire an adherent layer of tungsten oxide; water-rinsing the wire to remove by-products of the oxidation of the tungsten; passing the wire through an aqueous suspension of graphite to provide a coating of graphite on the layer of tungsten oxide; heating the wire to a temperature of about 300 C.; and thereafter passing the wire through a reducing die.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Metal Extraction Processes (AREA)

Priority Applications (5)

Applications Claiming Priority (1)

Publications (1)

Family

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Family Applications (1)

Country Status (5)

Families Citing this family (2)

Citations (7)

• 1964
  • 1964-05-25 US US370108A patent/US3262293A/en not_active Expired - Lifetime
• 1965
  • 1965-05-21 DE DE1965P0036861 patent/DE1521925B2/de active Pending
  • 1965-05-21 FR FR17866A patent/FR1433993A/fr not_active Expired
  • 1965-05-24 NL NL6506553A patent/NL6506553A/xx unknown
  • 1965-05-24 BE BE664352D patent/BE664352A/xx unknown

Patent Citations (7)

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