US2271379A - Method of heat treating wire - Google Patents

Description

Jan. 27, 1942. J. STATZ ETAL METHOD OF HEAT: TREATING WIRE Filed July 22, 1938 2 Sheets-Sheet 1 1 III Jail. 27, 1942. J. smz ETAL METHOD OF HEAT TREATING WIRE Filed Ju1 22, 1938 2 Sheets-SheetR m a m m J05EPH 14/ SW/FT m1 JOHN, 57??- Patented Jan. 27, 1942 METHOD OF HEAT TREATING WIRE John Statz and Joseph H. Swift, Worcester, Mass., assignors to The American Steel and Wire Company of New Jersey, a corporation of New Jersey Application July 22, 1938, Serial No. 220,799

1 Claim.

The present invention relates to a method of heat treating wire.

It is among the objects of the present invention to heat treat wire in an inexpensive but extremely eflicient manner.

Another object is to heat treat and cool wire in such manner that oxidation will be prevented.

A further object resides in maintaining the wire in a straight and substantially horizontal path during the period of change in grain structure resulting from heating so that no strains are set up in the wire during such a period.

Other objects and advantages will become apparent as the description proceeds and reference is had to the accompanying drawings, in which:

Figure 1 is a side elevation of the present invention in combination with a heat treating furnace;

Figure 2 is a section on the line II-II of Figure 1;

Figure 3 is a section on the line IIIIII of Figure 1; and,

Figure 4 is a detailed section on the line IV-IV of Figure 3.

In the drawings, in which there is illustrated a type of apparatus for practicing the present method of heat treating and coating wires, the numeral l represents a conventional hearth type of furnace. In a process of heat treating wire, the furnace l is maintained at varying temperatures up to 1650 degrees Fahrenheit. As the wires leave the furnace I, they are subjected to a cooling step when heat treating is being practiced.

There is provided adjacent the exit end of the furnace, a kettle furnace 2 of conventional design upon which is positioned a kettle 3 adapted to contain the cooling medium. The cooling medium may comprise a liquid salt.

An auxiliary trough 4 is supported, in any conventional manner, within the kettle 3 and is provided with an opening 4 extending trans-- versely thereof. A feed pipe 5, having an opening adapted to communicate with the opening 4 formed in the troughl, communicates with a pump 6 driven by motor I for receiving the cooling medium and distributing the same into the kettle 3. Positioned on the vertical sides of the trough 4 between guide plates l5 are a plurality of plates 8 having apertures 9 through which the wires being treated are adapted to pass in the, same horizontal plane. These apertured plates also maintain the desired level of the cooling medium within said trough 4. The trough 4 is provided with one or more openings 4 upon which rests cover plates 4 while, at the outlet side of said kettle furnace 2, the trough 4 is provided with a'transversely extending opening 4'. These openings permit the cooling material to 5 fall into said kettle 3 and, depending upon how many cover plates 4 are removed, the length of immersion of said wire within the cooling material is controlled. As shown in Figure 4, the cooling material ,falls into the kettle 3 near the outlet end of said furnace 2 and by controlling the length of immersion of the wire in the cooling medium. As the cooling material flows through said openings 4 and/or 4, it passes into said kettle 3, through the pipe Ill into the container or kettle J3, and back through the pump for recirculation in the trough 4. fl'hereforepa more uniform temperature of the treating bath is maintained. Any desired typeof heat resisting packing I! may be provided for the joint be-"" tween the opening formed in the auxiliary trough 4 and the pipe 5. The apertures 9 in the plates I may be substantially the same diameter as the wires being fed from the furnace, or, if desired, may be considerably larger than the wire being quenched.

Positioned over the auxiliary trough 4 and extending from the exit end of .the furnace throughout the entire length of said trough 4 is a cover l4 adapted to retain a body of inert gas over the surface of the cooling medium and thereby prevent oxidation of the surface of the molten metal. The inert gas is supplied to the cover by means of the pipe l6 connected to the blower l6 which draws the inert gas from the heating furnace I through pipe ll.

In the heat treating of wires, the surface frequently becomes scratched or spotted due to abrasion between the sinker rolls or bars which lead the wire or wires beneath the cooling medium. In order to eliminate the possibility of spotting or scratching the wires, we provide, under the present invention, the pump 6 in a separate kettle off to one side of the drawing furnace for the purpose of circulating the cooling 5 medium beneath the wires being treated. While there is shown a separate kettle I 3 for receiving the cooling medium and pumpi, if desired, this separate kettle can be eliminated and the pump can be readily adapted to existing apparatus.

The flow of the coolingmedium is controlled by the speed of the rotary pump 8 which delivers the cooling medium to the auxiliary trough 4 and thereby maintains a uniform temperature of the cooling medium throughout the entire length of the bath.

Furthermore, if desired, the length of immersion of the wires within the coolant can be regulated by providing the auxiliary trough l with openings in the bottom thereof at predetermined points which will permit the coolant to pass therethrough and return to the pump chamber. The cooling medium is circulated underneath the wires being treated, which, in the present invention, are maintained in a. straight and substantially horizontal path so as to eliminate any possibility of their becoming bent while being treated.

According to the teachings of the present invention, the wires being treated are submerged in a substantial body of coolant in the trough 4. Before entering the trough I, the wires are enveloped and surrounded by a body of heated inert gas, which prohibits any substantial cooling and also any oxidation of the wires. The heated inert cooling of the coolant, which can thereby be kept at a fairly uniform temperature and, at the same time, this inert gas prevents the contact of any air with the coolant.

While we have shown and described a specific embodiment of the present invention, it will be understood that we do not wish to be limited exactly thereto, since various modifications may be made to the invention without departing from the scope thereof as defined by the following claim.

We claim:

The method of treating wire which comprises heat treating the same, immersing the wire while still in a heated condition in a liquid cooling medium in an inert atmosphere, and maintaining the wire in a straight and substantially horizontal path and in contact only with the liquid cooling medium during the treatment.

JOHN STATZ. JOSEPH H. SWIFT.

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