CONTINUOUS ANNEALER FOR WIRE

Abstract

A continuous annealer for wire is disclosed, and specifically for annealing and recrystallizing a wire in a continuous process. The continuous annealer for wire comprises: two contact discs for contacting a first wire portion extending therebetween; an annealing zone situated between the two contact discs; and annealing means for annealing the first wire portion in the annealing zone, as a result of which a first partial recrystallisation process in the first wire portion takes place in the annealing zone. A recrystallisation zone is situated downstream of the second contact disc, wherein, downstream of the annealing zone, the first wire portion passes through the recrystallisation zone as the second wire portion, and a second partial recrystallisation process takes place in the second wire portion. The wire has the opportunity to recrystallize further after leaving the annealing zone without further heating. By extending the recrystallisation time, the recrystallisation temperature can be reduced accordingly. As a result, the same degree of recrystallisation can be achieved overall with a significantly lower input of energy than when the wire is cooled immediately after leaving the annealing zone.

Claims

1. A continuous annealer for wire for annealing and recrystallizing an in particular metallic wire in a continuous process which comprises: at least two contact disks which are configured such that a first contact disk contacts a rear end, seen in the wire's direction of travel, and a second contact disk contacts a front end, seen in the wire's direction of travel, of a first wire portion extending between the first contact disk and the second contact disk, an annealing zone situated between the first contact disk and the second contact disk which is configured such that the first wire portion passes through the annealing zone, as well as annealing means for annealing the first wire portion in the annealing zone, whereby a first partial recrystallization process takes place in the first wire portion in the annealing zone, wherein a recrystallization zone is situated downstream of the second contact disk, seen in the wire's direction of travel, which is configured such that a second wire portion, which has previously passed through the annealing zone as a first wire portion, passes through the recrystallization zone and that a second partial recrystallization process takes places in the second wire portion.

2. The continuous annealer for wire according to claim 1, wherein the annealing means are means for conductively heating the first wire portion, wherein the first contact disk and the second contact disk are configured to respectively feed or discharge an electric current into or from the first wire portion.

3. The continuous annealer for wire according to claim 1, wherein the annealing means are means for inductively heating the first wire portion.

4. The continuous annealer for wire according to claim 1, the wherein the crystallization zone is configured to dispose the second wire portion under a protective gas.

5. The continuous annealer for wire according to claim 1, wherein it has no cooling device for the wire between the annealing zone and the recrystallization zone.

6. The continuous annealer for wire according to claim 1, wherein it has a cooling device for cooling the second contact disk.

7. The continuous annealer for wire according to claim 6, wherein the cooling device for cooling the second contact disk comprises means for spraying the second contact disk with a cooling medium, particularly an emulsion or oil.

8. The continuous annealer for wire according to claim 1, wherein a cooling zone and/or a cooling basin is/are situated downstream of the recrystallization zone seen in the wire's direction of travel, and configured such that a third wire portion, which has previously passed through the recrystallization zone as a second wire portion, passes through the cooling zone and/or the cooling basin and is cooled therein by a cooling medium.

9. The continuous annealer for wire according to claim 8, wherein it comprises the cooling zone and that the cooling zone has means for spraying the third wire portion with a cooling medium, particularly an emulsion or oil.

10. The continuous annealer for wire according to claim 9, wherein the cooling zone comprises at least one apparatus for regulating the volumetric flow of the cooling medium in the cooling zone, wherein the apparatus in particular has at least one valve for introducing cooling medium into the cooling zone and the at least one valve is adjustable and in particular designed as a proportional valve.

11. A method for annealing and recrystallizing a wire in a continuous process in a continuous annealer for wire according to claim 1, wherein a first wire portion passes through the annealing zone, is annealed there and a first partial recrystallization process thereby takes place in the first wire portion as well as that a second wire portion, which has previously passed through the annealing zone as a first wire portion, passes through the recrystallization zone and a second partial recrystallization process thereby takes place in the second wire portion.

12. The method of claim 11, wherein the wire is metal.

Description

[0056] Further advantages, features and possible applications of the present invention yield from the following description in conjunction with the figures. Shown therein:

[0057] FIG. 1 a continuous annealer for wire from the prior art without a recrystallization zone;

[0058] FIG. 2 an inventive continuous annealer for wire with a recrystallization zone.

[0059] FIG. 1 shows a continuous annealer for wire 1 from the prior art which has an annealing zone 8 and a cooling zone 4, although no recrystallization zone.

[0060] The wire 12, which was drawn in a drawing machine (not illustrated) to a specific diameter and thereby solidified, is heated in the continuous annealer for wire 1 and thereby recrystallized in order to largely suspend the solidification and thus in particular the residual strain; i.e. to increase the maximum ductility prior to wire breakage.

[0061] The wire 12 is inserted into the continuous annealer for wire 1 at the left edge and initially runs around a deflection roller 10. All the contact disks of the continuous annealer for wire 1 according to FIGS. 1 and 2 are likewise designed as deflection rollers. The wire 12 then passes through several other deflection rollers. The throughput speed of the wire 12 through the continuous annealer for wire 1 amounts to, for example, 30 m/s.

[0062] The wire 12 thereafter reaches the first contact disk 2, travels around same, and passes into the annealing zone 8 where it is heated. The annealing zone 8 is designed as a closed housing (apart from the inlet and outlet openings for the wire 12) such that the lowest amount of thermal energy possible can escape into the environment from the heated wire. The length of the annealing zone 8 in the continuous annealer for wire 1 according to FIG. 1 amounts to, for example, 2000 mm. The section of the wire 12 which passes through the annealing zone 8 is referred to as the first wire portion. The arrow above the annealing zone 8 indicates the wire's direction of travel in the annealing zone 8.

[0063] The heating of the first wire portion ensues by a voltage being applied to the first contact disk 2 and the second contact disk 3, preferably a direct current voltage, however particularly preferentially an alternating current voltage, whereby a direct current or alternating current respectively flows through the first wire portion which heats the first wire portion due to its ohmic resistance. The wire 12 thereby reaches a temperature of e.g. 550? C. as it enters into the inlet cooling nozzle 7 of the cooling basin 9.

[0064] Due to being heated, the first wire portion experiences a first partial recrystallization process in the annealing zone 8, whereby the first wire portion's solidification induced by the preceding drawing process is largely suspended.

[0065] The wire 12 exits the annealing zone 8 at the entrance to the cooling basin 9 where it enters into the inlet cooling nozzle 7. The wire 12 is sprayed or sprinkled with a cooling medium, which is preferably an emulsion or oil, in the inlet cooling nozzle 7 of the cooling basin 9 so as to already dissipate part of the thermal energy from the wire 12 at this point. The wire 12 is thereafter guided around a second contact disk 3 within the cooling basin 9. The cooling basin 9 is filled with a further cooling medium so that the second contact roller 3 as well as the section of the wire 12 running around it are completely submerged in the cooling medium. The cooling medium in the cooling basin 9 draws the heat off from this wire portion. The heated cooling medium is discharged continuously or at specific time intervals and replaced with cold cooling medium. The wire 12 ultimately exits the cooling basin 9 again through the outlet cooling nozzle 6, in which the wire 12 is again sprayed or sprinkled with a cooling medium.

[0066] The wire 12 subsequently passes through a cooling zone 4. This also exhibits a closed housing (apart from the inlet and outlet openings for the wire 12) which is flooded with a further cooling medium and in which the wire 12 is completely submerged. The arrow above the cooling zone 4 indicates the wire's direction of travel in the cooling zone 4.

[0067] By way of the cooling basin 9 with cooling nozzles 6 and 7 as well as the cooling zone 4, the wire 12 is cooled to a temperature enabling its further processing, in particular being wound onto a spool. However, only the lowest amount of thermal energy as possible is drawn off from the wire 12 in order to ensure the required final temperature when winding (approximately 50? C.).

[0068] The wire 12 still wet with cooling medium ultimately passes through a drying zone 5 in which it is dried, preferably by air blown into said drying zone 5.

[0069] The wire 12 is thereafter led out of the continuous annealer for wire 1 at the right edge via several other deflection rollers in order to be further processed there, in particular wound onto a spool (not depicted).

[0070] FIG. 2 shows an inventive continuous annealer for wire 1 with a recrystallization zone 11.

[0071] The inventive continuous annealer for wire 1 according to FIG. 2 is based on the continuous annealer for wire 1 from the prior art according to FIG. 1 and exhibits some modifications compared thereto. Therefore, there will be no reiterated description of the elements of the two continuous wire annealers 1 which correspond to one another.

[0072] The wire 12 is guided to the annealing zone 8 as in FIG. 1 and heated there, whereby the first wire portion experiences a first partial recrystallization process and then likewise enters the cooling basin 9.

[0073] Should there be an inlet cooling nozzle at the entrance of the cooling basin 9, it is preferably not utilized. The same applies to any outlet cooling nozzle at the exit of the cooling basin 9. The wire 12 is again guided around a second contact disk 3 (not depicted in FIG. 2) within the cooling basin 9.

[0074] The wire 12 is only cooled slightly or not at all in the cooling basin 9. Preferably, only the second contact disk 3 is sprayed with a further cooling medium in order to cool it while the wire 12 remains largely uncooled. Preferably, while the cooling basin 9 can also be flooded with the cooling medium, it is preferably just minimally circulated and replaced, or not at all, so that only a small amount of thermal energy is drawn off by the cooling medium. The question of how much cooling medium needs to be in the cooling basin 9; i.e. the fill level of cooling basin 9, can be determined experimentally and can differ depending on environment.

[0075] The wire 12 then passes through the recrystallization zone 11 whichlike the cooling zone 4 arranged at the corresponding location in FIG. 1exhibits a largely closed housing. However, the wire 12 is not cooled in the recrystallization zone 11. The wire 12 is thus still warm enough after leaving the cooling basin 9 that a second partial recrystallization process can take place in the recrystallization zone 11.

[0076] The annealing zonein the sense of the section where recrystallization occurs in the wire 12is in this way lengthened so to speak, e.g. even doubled, wherein energy input, however, only occurs in the first partthe actual annealing zone 8.

[0077] While achieving the same degree of recrystallization, the input of thermal energy into the annealing zone 8 can thus be reduced, leading to the above-cited energy savings of up to 20%.

[0078] A protective gas atmosphere preferably prevails in the housing of the recrystallization zone 11, preferentially nitrogen or water vapor, in order to prevent oxidation and thus tarnishing of the surface of the wire 12.

[0079] The wire 12 then ultimately also passes through a cooling zone 4 and a cooling basin 13 in order for the temperature of the wire 12 to be lowered to a temperature suitable for the further processing. In the exemplary embodiment according to FIG. 2, the cooling zone 4 and the cooling basin 13 are, for reasons of space, at least partially arranged in an additional housing 15 which is flanged to the housing 14 of the continuous annealer for wire 1. The cooling zone 4 and the cooling basin 13 can, however, also be integrated into the housing 14 of the continuous annealer for wire 1. Providing only the cooling zone 4 or only the cooling basin 13 is also possible.

[0080] The wire 12 is submerged in a cooling mediumsimilar as in the continuous annealer for wire 1 in FIG. 1in cooling zone 4. The volumetric flow of the cooling medium can be regulated in the cooling zone 4, whereby the cooling effect on the wire 12 can also be regulated as a function of the diameter and the feed rate of the wire 12. This is preferably effected by at least one proportional valve (not depicted).

[0081] The wire 12 is likewise submerged in a cooling medium or even just sprayed with a cooling medium in the cooling basin 13.

LIST OF REFERENCE NUMERALS

[0082] 1 continuous annealer for wire [0083] 2 first contact disk [0084] 3 second contact disk [0085] 4 cooling zone [0086] 5 drying zone [0087] 6 outlet cooling nozzle [0088] 7 inlet cooling nozzle [0089] 8 annealing zone [0090] 9 cooling basin [0091] 10 deflection roller [0092] 11 recrystallization zone [0093] 12 wire [0094] 13 cooling basin [0095] 14 housing of continuous annealer for wire [0096] 15 housing of cooling zone and cooling basin