GB1587275A - Plant for the manufacture of wire from liquid metal - Google Patents

Description

(54) PLANT FOR THE MANUFACTURE OF WIRE FROM LIQUID METAL (71) We, MIGEIELIN & CIE (COM- PAGNIE GENERALE DES ETABLISSEMENTS MICHELIN), a French body corporate, of 4 Rue du Terrail, Clermont-Ferrand, Puy-de Dome, France, do hereby declare the inven tion, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state ment: This invention relates to improvements in plant for the manufacture of wire by project ing a stream of liquid metal into a gaseous cooling medium.

Such equipment essentially comprises a crucible containing a metal or metal alloy melted or kept melted by means of a heating element, at least one die disposed in a wall of ' the crucible and through which the stream is projected by means exerting pressure on the molten metal or metal alloy to project it in the form of a stream through the die and into a cooling medium. This medium is contained within a cooling enclosure dis posed around the orifice of the die and containing a gaseous medium in which the jet of liquid solidifies to a solid wire. Take up means are arranged to receive the resulting solid wire.

In such equipment, the stream has normally been projected so that it drops vertically and it is possible to obtain a con tinuous wire only by adding at least one stabilising element, such as silicon in the case of steel wires, e.g. as described in British Patent No. 1,396,406, to the molten metal in the crucible. This addition has the effect of sufficiently elongating the stream in order to obtain a wire before the stream resolves into drops. However, under indus trial conditions, it is difficult to produce with such equipment continuouswires having a diameter in excess of two or three-tenths of a millimetre, because- the weight of the wire breaks the stream prematurely despite the traction resistance of the skin formed around the stream by the - stabilizing element in contact with the cooling medium.

As described'in United States 'Patent No.

2,825,108 the stream of metal can be cooled by projecting it obliquely into a rotating dish made from a metal which is a good heat conductor, this dish being disposed close to the orifice of the die. Likewise, as described in United States Patent Not 2,879,566, a metal stream can be cooled by projecting it tangentially in respect of a stream of cold gas discharging close to the orifice of the die. However, in neither way it is possible industrially to produce a con tinuous wire of circular cross-section and constant diameter. It is therefore an object of the present invention to provide plant which can produce wire of larger diameter while retaining continuity during cooling.

Plant according to the invention for manu facturing wire by projecting a stream of metal or metal alloy into a gaseous cooling medium essentially comprises a crucible for the molten metal or metal alloy, at least one die disposed in the wall of the crucible, the axis of the orifice of the die making with the descending vertical an angle substant tially greater than 0 and less than 1800, means for exerting pressure on the molten metal or metal alloy to project it in the form of a stream through the die and into a gaseous cooling medium contained in a cool ing enclosure disposed around the orifice of the die, and a wire take-up means. When the stream is projected vertically downward the whole weight of the wire exerts traction on the stream. According to the invention however, - the influence of the weight of the wire is reduced and can be no longer material. Thus the weight on the wire is the downward component of a line tangent to the path of the stream and this component has a tendency to diminish as the angle of the axis of the die in respect to the descending vertical increases.

When using prior plant and projecting the stream vertically downwards at a speed of 15 - m/s, it is difficult to produce con tinuous steel wires of a diameter in excess of 0.3 mm even when the components of the steel and the cooling medium are those indicated in British Patent No. 1,396,406. On the other hand, by inclining the axis of the die according to the invention to about 60 with respect to the descending vertical, it is possible to produce at a projection rate of 15 m/s, continuous wires 0.4 mm in diameter. Wtih an angle of inclination of the die equal to about 100"C, wires 0.6 mm in diameter can be obtained. When the axis of the die is inclined at 1350, continuous wires 2 mm in diameter can be obtained.

The invention applies to the manufacture of continuous wires whatever the molten metal or metallic alloy projected in the form of a- jet into the cooling medium.

According to a preferred embodiment of the present invention, once continuity of the wire has been established, it is possible to introduce into the path of the wire which in a first approximati6n is parabolic, a device which limits the horizontal span of this path in order to avoid the plant being of a very large size. Such a device, while forming part of the means of receiving and/or convetting the \vise, rnay be fixed in the cooling ehclosure but may also be located outside thereof.

This span limiting device may be given the form of a plane or concave surface, its concavity being preferably directed towards the wire. At the point of contact of the wire with the surface, the tangent to the path of the wire is advantageously at an acute angle, for example less than 300, to the tangent on the said surface. The path is thus diverted but not upset.

The span limiter device may also take the form of two nip rollers rotating about fixed and parallel axes, at a speed close to that of the wire and in the same direction as the latter, the wire engaging within the two cylinders. On leaving this limiter device, the wire follows another path. Thus, it is convenient to orientate this limiter device in relation to the path of the wire in such a way that the wire emerging follows a path which is directed towards the wire receiving element.

The invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a vertical section through one plant according to the invention, the section containing the path of the stream and of the wire Figure 1A is an enlarged detail of area A of the section shown in Figure 1; and Figure 2 is a vertical section through sirniSår plant in which the means of limiting the span of the path of the wire is formed by a pair of cylinders disposed outside the .cooti4ng enclosure.

For an easier understanding of the draw ings, the diameter of the orifice in the die as well as the diameter and curvature of the path of the stream and of the wire have been exaggerated.

The plant shown in Figure 1 has a crucible 1 which contains metal melted by a heating element 3 surrounding the crucible 1. A die 4 is disposed in the side wall of the crucible 1. A pressurised enclosure 5 with an inlet 6 for pressurised gas encloses the crucible 1.

A cooling enclosure 7 with a cooling gas inlet 8 is disposed with one end surrounding the orifice of the die 4. In the vicinity of the other end of the cooling enclosure 7 is a bobbin 9 rotatably mounted on a spindle 10 and onto which the wire 12 formed is wound.

The axis 41 of the orifice of the die 4 forms an angle 1a of nearly 100" with the descending vertical Z.

The gas in the pressuring enclosure 5 is subject to sufficient pressure to project-the molten metal 2 through the die 4 and into the cooling enclosure 7.

The walls of the cooling enclosure are virtually parallel with the path of the stream 11 and, after this latter has solidified, of the wire 12. This path of the stream 11 and wire 12 is substantially parabolic from the die 4 as far as a point of contact 13 of the wire 12 with a device for limiting the span of the path of the wire. This device forms the end part of the cooling enclosure 7 and takes the form of a concave surface 14, the concavity of which is directed towards the wire 12. The tangent T (see Figure 1A) to the path of the wire 12 at the point of contact 13 with the surface 14 forms an acute angle ,ss to the tangent T1 at the point of contact 13 on the surface 14. From the point of contact 13 of the wire 12 with the surface 14, the wire follows a trajectory towards the bobbin 9 on which it is stored.

The bobbin drive means is not shown.

Since the paths of the jet 11 and of the wire 12 are almost horizontal, the component g of the weight G of the wire at the point P according to the tangent to the path is very small. At the chosen point P, the component g does not exert traction but instead a slight compression on the stream 11. In this way it is possible to have a greater length of the stream 11 for solidification before break-up of the stream occurs as compared with prior plant. Any increase of the angle la up to 1800 makes it possible to increase the available length of the stream 11 to solidify it, which makes it possible to increase the diameter of the stream 11 and consequently of the wire 12 produced by means of the plant according to the invention.

The plant shown in Figure 2 is equipped with a device 20 for limiting the path of the stream 12. This device 20 is disposed outside. the cooling enclosure 7. The wire emerges from the end portion of the enclosure 7 and becomes almost tangentially engaged between two rollers 21 and 22 rotating in opposite directions, in the direction of propagation of the wire and at a speed close to that of the wire, about two fixed axes 210 and 220. The means for driving the two cylinders is not shown. On leaving the limiting device 20 the wire goes to a storage bobbin 23.

WHAT WE CLAIM IS:- 1. Plant for manufacturing wire by projecting a stream of metal or metal alloy into a gaseous cooling medium and essentially comprising a crucible for the molten metal or metal alloy, at least one die disposed in the wall of the crucible, the axis of the orifice of the die making with the descending vertical an angle substantially greater than 0 and less than 1800, means for exerting pressure on the molten metal or metal alloy to project it in the form of a stream through the die and into a gaseous cooling medium contained in a cooling enclosure disposed around the orifice of the die, and a wire take-up means.

2. Plant as claimed in Claim 1 in which the axis of the orifice of the die forms an angle of at least 600 with the descending vertical.

3. Plant as claimed in Claim 1 or Claim 2 in which the axis of the orifice of the die forms an angle greater than 90" with the descending vertical.

4. Plant as claimed in any preceding claim in which the take-up means includes a device for limiting the horizontal span of the path of the wires.

5. Plant as claimed in Claim 4 in which the device for limiting the horizontal span of the path of the wire is fixed inside or outside the cooling enclosure.

6. Plant as claimed in Claim 4 or Claim 5 in which the device for limiting the span of the path of the wire is formed by a plane or concave surface, the concavity of which is directed towards the wire, and is disposed in such a way that, at the intended point of contact of the wire with the said surface, the tangent to the path of the wire forms an acute angle with the tangent to the said surface.

7. Plant as claimed in Claim 6 in which the said acute angle is less than 30".

8. Plant as claimed in Claim 4 or Claim 5 in which the device limiting the span of the path of the wire is formed by two rollers rotating about parallel and fixed axes, the rollers being arranged to be driven at a speed close to that of the wire, and being disposed in such a way that the wire engages between the two rollers.

9. Plant as claimed in any of claims 4 to 8 in which the device limiting the span of the path of the wire is so orientated that the wire emerging from this device follows a path towards a wire receiving element.

10. Plant for manufacturing wire by projecting a stream of metal or metal alloy into a gaseous cooling medium substantially as herein described with reference to Figures 1 and 1A or to Figure 2, of the accompanying drawings.

11. Metal wire when manufactured by plant as claimed in any preceding claim.

12. A method of manufacturing metal wires using a plant as claimed in any of

Claims (1)

1. claims 1 to 10.

   13. A method as claimed in Claim 12 in which the metal is steel.

   14. Metal wire when made by a method as claimed in Claim 12 or Claim 13.