US1488992A - Process of and apparatus for annealing wire - Google Patents

Description

April 1 1924.

-K.' B. Lgwis PROCESS OF APPARATUS 'FORANNEALTNUWIRE Filed June 4, 19 2-0" lid Patented Apr. 1, 1924.

UNTTET) STAES KENNETH B. LEWIS, 0F WORCESTER,

STBUCTION COMPANY 0F WORCESTER, MASSACHUSETTS, A CORPORATION 0E MASSACHUSETTS.

OF AND APPARATUS FOR ANNEALING WIRE.

Application filed June 4 T 0 all whom it may concern:

Be it known that T, KENNETH B. LEWIS, a citizen of the United States, residing at Worcester, in. the county of \Vorcester and Commonwealth of lllassachusetts, have invented a new and useful Improvement in a Process of and Apparatus for Annealing -Wire, of which the following, together with the accompanying drawings, is a specification.

The present invention relates to the art of annealing wire and contemplates, primarily, a method of treatment that is adapted to secure a clean bright product from the annealing operation.

The ordinary methods of annealing invariably leave the wire in a condition that requires subsequent thorough cleaning, by subjection to a bath of acid or the like; this procedure is open to the serious objection that the cleaning agent is apt to eat into the metal, thereby reducing its cross section and affecting its tensile strength. The necessity for cleaning arises from two causes ;first, the presence on the wire, as an incident of the drawing operation, of a film of lubricant, soap, grease, or the like, which, when subjected to the temperature of an ordinary annealing furnace, dries out and remains on the wire in the form of a coating. And second, the formation on the wire of the usual scale by oxidation. which can only be prevented by the use of the special apparatus for annealing the wire in a non-oxidizing atmosphere; even then, of course, the coating of dried lubricant remains.

The present invention eliminates the necessity for subsequent cleaning or pickling by the adoption of a mode of treatment which removes the foreign substances from the surface of the wire, simultaneously with the annealing of the same. The invention is predicated on the discovery that the capability of. molten borax for dissolving metallic oxides and salts may be availed of in the annealing of wire by using molten borax as an.annealing medium. The details of the improved method, and the apparatus which may be employed in putting the same into practice are fully set forth in the following description, reference being had to the accompanying drawings, in wluch Fig. 1 is a diagrammatic view illustrat- 1920. Serial No. 386,546.

ing the invention as applied, in a continuous manner, to moving wire in the process of being coiled, and

Fig. 2 is a transverse sectional view of a receptacle that may be employed for the bright annealing of a formed coil of wire.

Referring first to Fig. 1, the wire a is shown in transit, for instance, between a pair of reels 1, 1 and moving in the direction indicated by the arrows. Intel-posed between the reels 1. 1' is a suitable receptacle 2 in which is maintained a bath of molten borax. The wire a enters the r eceptacle on one side and leaves at the other, suitable means, such as guides 3, 3, being employed to insure the thorough immersion and passage of the wire through the annealing medium, which is kept in a molten condition by the application of heat to the receptacle and which is replenished as needed so as always to cover the wire.

The borax in receptacle 2 is maintained in a fused condition at such a temperature that the annealing of the wire is accomplished by its passage through said me dium; obviously, the necessary conditions to procure this result may be established in any given case by varying the duration in the bath of thewire. The molten borax acts as a complete solvent for the film or coating oflubricant on the wire, and also for any metallic oxide which may have formed thereon previously. At the delivery side of the receptacle 2, the wire emerging from the bath passes through suitable wipers l. which prevent any excessive quantity of the borax from leaving the receptacle by adhesion to the wire, and which serve the additional purpose of causing the annealing medium to remain on the wire in a thin film, which quickly hardens thereon. This film acts as a protective coating for the bright clean wire emerging from the annealing bath, and prevents the surface of the wire from being exposed to the air at such a temperature that ogtidation might occur.

The wire cools with this protective coating on its surface and the hardening of this protective coating renders it easily removable, as for instance by passing the wire over and under a plurallty of staggered rolls 5, 5. so arranged as to cause the wire to take an irregular course. This deviation CHUSETTS, ASSIGNOR T0 MORGAN CON-- l 1 not i l or bending of the wire, b contact with the surfaces of rolls 5, has t e effect of cracking and breaking off the protective coating 7 of borax, so that the wire presents a bright is maintained. The'receptaele 6 is adapted to receive an annular coil of wire 7, the convolutions of which, when the coil is placed in the bath, are exposed to the action of the borax. The coil 7 is left in the heated medium a sufficient time to effect the annealing of the .wire, and thereafter, when the coil is removed, the borax adheres'to the wire and prevents oxidation wlilile cooling, The protective coating of borax on the wire ofthc coil may be removed by jarring or bouncing the coil in such a manner that the covering film is cracked up and breaks off, leaving the coil bright and clean.

It is obvious that various-other forms of apparatus are adapted to the accomplishment of the various steps involved in the novel process of bright annealing herein set forth, and I do not wish to be limited to the mechanism here shown and described for procuring the results set forth. \Vhile I have described the process as employing molten borax as the annealing medium. it is to be understoodthat the invention is not limited to this material, except as defined in the appended claims, but contemplates other materials, or combinations of ma terials. having similar properties, viz, the capability of dissolving salts and metallic oxides without subjecting the'wire to ill- It is also to be understood that the term annealing herein is used in its generic sense and contemplates any heat treatment. carried on for the purpose of changing the physical properties of the metal, in such amanner as to obviate or relieve the strains therein that arise from working same when cold,--as for instance the treatment involving continuously a limited heating and commonly known in the art as patenting.

Iclaim,

1. The herein described process of annealing wire, which consists in immersing the wire in an annealing bath that has the property of dissolving the drawing lubricant and oxide on the wire.

2. The herein described process of annealing wire, which consists in immersing the wire in a substance having the property of dissolving lubricant and scale on the surface of the wire, and maintaining said substance at an annealing temperature.

3. T he herein described method of annealing wire, which consists in passing the wire througha bath of molten borax, forming a protective coating of borax. on the wire elncrging from said bath, and removing said protective coating after the wire has cooled. 4. The improvementin the art of anneal ing wire, which consists in using a heated molten medium, maintained at the annealing temperature, to dissolve foreign matter and cxi to on the surface of the wire. 7

The impmvtunent in the art of annealing wire, which consists in passing the wire borax.

6. The improvement in the art of annealing wire, which consists in passing wire continuously through a bath of molten borax, causing the borax to form a coating on the wire as it emerges from said bath, procuring the hardening of said coating by cooling of said wire, and finally removing said coating. 7

7. In apparatus of the class described, means for procuring the continuous passage of wire through a bath of molten borax, means for producing a protective film of said substance on the wire as it leaves said bath, and means for removing said film after cooling of said wire. i

8. In appa'atus of the class described,

means for passing wire through a bath of molten borax, means for maintaining said bath at annealing temperature, and means for preventing the exposure of the wire leaving said bath to the atmosphere until said wire has cooled.

Dated this thirteenth day of May, 1920. KENNETH B. LEWIS.

through a bath of molten"

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