GB1580433A

GB1580433A - Method of and apparatus for continuously forming and apparatus for continuoulsy forming a flexible elongate member

Info

Publication number: GB1580433A
Application number: GB2074376A
Authority: GB
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1976-05-19
Filing date: 1976-05-19
Publication date: 1980-12-03
Also published as: CA1090982A; AU2522577A

Description

(54) A METHOD OF AND APPARATUS FOR CONTINUOUSLY FORMING A FLEXIBLE ELONGATE METALLIC MEMBER (71) We, BIce LIMITED, a British Company of 21 Bloomsbury Street, London, WC1B 3QN, do hereby declare the invention, 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 statement: This invention relates to forming a flexible elongate member of metal, the term "metal" as used in this specification being employed in its broadest sense to include any metal or metal alloy that can exist in rod or wire form.

It is an object of the present invention to provide an improved method of forming as a continuous process from molten metal a flexible elongate metal member.

According to the invention the method comprises causing molten metal contained in an upstanding, preferably substantially vertical, tube to be ejected out of the open upper end of the tube whilst, at the same time, establishing about said open upper end an alternating electromagnet field which sets up forces such as to cause the ejected molten metal to be compressed inwardly to form a column of molten metal which protrudes from the open upper end of the tube; cooling said column of molten metal to such an extent that at least an upper end part of the column is in a substantially solid state; and, whilst feeding molten metal into a lower part of the tube, withdrawing the substantially solidified part of the column of metal upwardly in the form of a continuous flexible elongate metal member.

The alternating electromagnetic field established about the open upper end of the tube induces eddy currents in the molten metal being ejected out of the upper part of the tube and the interaction between these eddy currents and the.electromagnetic field causes an electrodynamic fdrce to be set up, which force has the effect of causing the metal to compress inwardly and form a column of metal that protrudes from the open upper end of the tube. The forces set up by the alternating electromagnetic field may be such that, as compared with the internal cross-sectional area of the tube, the cross-sectional area of the column of molten metal is reduced to an extent that the flexible elongate metal member that is continuously withdrawn upwardly from the tube is in rod or wire form and requires no further change in cross-sectional shape and/or reduction in cross-sectional size. Alternatively, the flexible elongate member that is withdrawn upwardly from the tube may be in rod or other form of a shape and size suitable for rolling down to rod form of smaller diameter or for drawing down into wire.

Preferably molten metal is caused to be ejected out of the open upper end of the tube by controlled continuous feeding of molten metal into a lower part of the tube and preferably the molten metal is fed into the tube from a container of molten metal which is connected to but remote from the tube and which constitutes, in effect, the other limb of a U-tube. Molten metal may be fed at a controlled rate into the container from a source of supply, for instance a holding furnace. Preferably the surface area of the molten metal in the container is substantially greater than the cross-sectional area of the tube. Molten metal may be continuously fed from the container into the lower end of the tube under controlled fluid pressure, e.g. air pressure, that is greater than atmospheric pressure.

Cooling of the column of metal to such an extent that at least an upper end part of the column is in a substantially solid state may be effected by any convenient means but, preferably, initial cooling of the column and withdrawal of the column upwards from the alternating electromagnetic field at the upper open end of the tube is effected by means of a cold dummy member which is brought into contact with the upper end of the column to cause the upper end to solidify and bond to the dummy member and to which is connected a flexible line extending to haul-off means. The linear speed of withdrawal of the flexible elongate member so formed, having regard to the rate of cooling of the upper part of the column, will be such that there is no risk that fracture of the column will occur in the vicinity of the solidified or partially solidified part of the column.

Preferably, on emerging from the alternating electromagnetic field, the solidified upper part of the column of metal and the succeeding flexible elongate metal member are subjected to a cooling medium, for example cold air or water sprays.

The haul-off means may consist of or constitute a part of a take-up device or it may serve to feed the flexible elongate member to, or it may constitute a part of, treatment or processing apparatus. The flexible elongate member may pass directly to the haul-off means or, in travelling to the haul-off means, pass through reducing rolls or other reducing means and/or it may pass part way around one or more than one guide roller.

Where the cross-sectional area of the flexible elongate member is reduced as it travels towards the haul-off means, the haul-off means, and if a rotatably driven guide roller or rotatably driven guide rollers is or are present the or each guide roller, will each be driven at such a rotational speed that the linear speed of the flexible elongate member emerging from the upper end of the tube is substantially constant.

The invention also includes apparatus for use in the method of forming a flexible elongate metal member, which apparatus comprises a container for molten metal; at least one upstanding tube open at its upper end and connected at or near its lower end to said container so that metal in said container can be forced into said tube for upward ejection from the open upper end of the tube; an electromagnetic inductor positioned around the open upper end of the tube, which inductor will establish about said open upper end an alternating electromagnetic field which will set up forces that will cause molten metal being ejected upwardly from said open upper end to be compressed inwardly to form a column of molten metal protruding from said open upper end; a cooling chamber housing means for producing sprays of cold air or water and so positioned with respect to the open upper end of the tube that said sprays will cool at least an upper end part of a column of molten metal being ejected from the open upper end of the tube; and means for withdrawing upwardly a substantially solidified part of said column of metal.

Preferably for initially cooling at least an upper end part of the column of metal and for withdrawing the column upwards a dummy member is provided which is of a shape and size suitable for bringing into contact with the upper end of a column of molten metal protruding from the upper open end of the or each tube and which is connected by a flexible line to haul-off means.

Preferably, when the apparatus is in use, the source of molten metal is a container of molten metal remote from the tube or tubes and the lower end of the or each upstanding tube is connected to an outlet in the lower part of the container by a pipe, the or each tube, associated pipe and container, in effect, constituting a U-tube.

The method and apparatus of the present invention are especially suitable for use in forming rod or wire of copper alloy and of aluminium alloy.

The invention provides several important advantages that are not present in conventional methods of forming a flexible elongate member in which a stream of molten metal is arranged to flow downwardly from an outlet in a lower part of a container of molten metal. Firstly, the upstanding tube from which the column of metal is drawn upwardly can be spaced a substantial distance from the container or other source of supply of molten metal with the result that cooling of metal, e.g. by cooling water, is much safer than is the case when cooling water is positioned below a container holding a large quantity of molten metal. Secondly, should the column of metal being withdrawn upwardly from the tube fracture for any reason or should the source of power to the means establishing the alternating electromagnetic field fail, little or no molten metal or semimolten metal will spill over the upper end of the upstanding tube so that there is negligible risk to personnel. Thirdly, since the upstanding tube can be spaced a substantial distance from the container or other source of supply of molten metal, a single container or other source can be employed to feed molten metal to two or more upstanding tubes, upward withdrawal of a column of metal from each tube being independently controlled. Fourthly, the flexible elongate metallic member can be directed to a take-up device or process or treatment apparatus by passing the flexible member around appropriate guide pulleys supported above the ground with a consequential saving in floor space.

The invention is further illustrated by a description, by way of example, of the pre ferred method of an apparatus for use in forming two flexible rods of copper with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a diagrammatic representation of the apparatus, and Figure 2 is a diagrammatic representation, on a larger scale, of the preferred method of initially cooling and withdrawing the rod.

Referring to the drawings, the apparatus comprises a container 1 which contains molten copper C fed into the container from a holding furnace 2. The container 1 is surrounded by thermal insulation 3 and the copper in the container is maintained in the molten state at a temperature of about 1150"C by electrical heating coils 4. Two substantially vertical tubes 6, positioned remote from the container 1, are fed with molten copper from the container through pipes 7, one end of each of which is connected to a lower part of the container 1 and the other end of each of which is connected to the lower end of one of the tubes 6. The pipes 7 are surrounded by thermal insulation 8 and are heated by heating coils 9.

The upper open end of each vertical tube 6 is surrounded by an electromagnetic inductor 11, the upper part of the inductor being housed in the lower part of a cooling chamber 12 housing means for producing sprays of cold water. A guide pulley 14 is positioned above each cooling chamber 12.

Each tube 6 has a bore of circular crosssection and of a cross-sectional area of 100 sq mm. The internal cross-sectional area of the main body of the container 1 is 1.0 sq m.

At the start of operations, the level of molten copper C in the container 1 is such that the level of molten copper in each of the tubes 6 is just below the upper open end of the tube. A predetermined quantity of molten copper C is now introduced into the container 1 from the holding furnace 2 to form in the container 1 a sufficient head of molten copper to cause molten copper to be ejected from the open upper end of each tube 6 (Figure 2). At the same time, an alternating current having a frequency of 500 kHz is caused to flow through each of the inductors 11 to establish an electromagnetic field about the open upper end of the associated tube 6 which sets up forces such as to cause the ejected copper to be compressed inwardly to form a column 20 of molten copper which protrudes from the open end of the tube (Figure 2). With the column 20 of copper protruding from each tube held in this position, a cold dummy member 15, attached to a flexible line (not shown) connected to a haul-off device (not shown), is lowered into contact with the upper end of the column 20 to cause the upper end part of the column to solidify and bond to the dummy member at 21.

When a firm bond has been obtained, the haul-off device is brought into operation to draw the dummy member 15 and solidified part of the column 20 upwardly whilst, at the same time, molten copper is introduced from the holding furnace into the container 1, the rate of feed of molten copper into the container 1 and the speed of upward withdrawal of each of the haul-off devices being such that a continuous flexible copper rod 22 is drawn upwardly from each tube 6 through the cooling chamber 12, where the rod is cooled by water sprays, and over the pulley 14, without fracture of the column 20 of molten copper protruding from the tube.

WHAT WE CLAIM IS:- 1. A method of forming as a continuous process from molten metal a flexible elongate metal member which comprises causing molten metal contained in an upstanding tube to be ejected out of the open upper end of the tube whilst, at the same time, establishing about said open upper end an alternating electromagnetic field which sets up forces such as to cause the ejected metal to be compressed inwardly to form a column of molten metal which protrudes from the open upper end of the tube; cooling said column of molten metal to such an extent that at least an upper end part of the column is in a substantially solid state; and, whilst feeding molten metal into a lower part of the tube, withdrawing the substantially solidified part of the column of metal upwardly in the form of a continuous flexible elongate metal member.

2. A method of forming as a continuous process from molten metal a flexible elongate metal member which comprises causing molten metal contained in an upstanding tube to be ejected out of the open upper end of the tube whilst, at the same time, establishing about said open upper end an alternating electromagnetic field which sets up forces such as to cause the ejected metal to be compressed inwardly to form a column of molten metal which protrudes from the open upper end of the tube; bringing a cold dummy member, which is connected to a flexible line extending to haul-off means, into contact with the upper end of the column; cooling said column of molten metal to such an extent that at least an upper end part of the column is in a substantially solid state and bonds to the dummy member; and, whilst feeding molten metal into a lower part of the tube, operating the haul-off means to withdraw upwardly the dummy member with the substantially solidified part of the column of metal bonded

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ferred method of an apparatus for use in forming two flexible rods of copper with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a diagrammatic representation of the apparatus, and Figure 2 is a diagrammatic representation, on a larger scale, of the preferred method of initially cooling and withdrawing the rod. Referring to the drawings, the apparatus comprises a container 1 which contains molten copper C fed into the container from a holding furnace 2. The container 1 is surrounded by thermal insulation 3 and the copper in the container is maintained in the molten state at a temperature of about 1150"C by electrical heating coils 4. Two substantially vertical tubes 6, positioned remote from the container 1, are fed with molten copper from the container through pipes 7, one end of each of which is connected to a lower part of the container 1 and the other end of each of which is connected to the lower end of one of the tubes 6. The pipes 7 are surrounded by thermal insulation 8 and are heated by heating coils 9. The upper open end of each vertical tube 6 is surrounded by an electromagnetic inductor 11, the upper part of the inductor being housed in the lower part of a cooling chamber 12 housing means for producing sprays of cold water. A guide pulley 14 is positioned above each cooling chamber 12. Each tube 6 has a bore of circular crosssection and of a cross-sectional area of 100 sq mm. The internal cross-sectional area of the main body of the container 1 is 1.0 sq m. At the start of operations, the level of molten copper C in the container 1 is such that the level of molten copper in each of the tubes 6 is just below the upper open end of the tube. A predetermined quantity of molten copper C is now introduced into the container 1 from the holding furnace 2 to form in the container 1 a sufficient head of molten copper to cause molten copper to be ejected from the open upper end of each tube 6 (Figure 2). At the same time, an alternating current having a frequency of 500 kHz is caused to flow through each of the inductors 11 to establish an electromagnetic field about the open upper end of the associated tube 6 which sets up forces such as to cause the ejected copper to be compressed inwardly to form a column 20 of molten copper which protrudes from the open end of the tube (Figure 2). With the column 20 of copper protruding from each tube held in this position, a cold dummy member 15, attached to a flexible line (not shown) connected to a haul-off device (not shown), is lowered into contact with the upper end of the column 20 to cause the upper end part of the column to solidify and bond to the dummy member at 21. When a firm bond has been obtained, the haul-off device is brought into operation to draw the dummy member 15 and solidified part of the column 20 upwardly whilst, at the same time, molten copper is introduced from the holding furnace into the container 1, the rate of feed of molten copper into the container 1 and the speed of upward withdrawal of each of the haul-off devices being such that a continuous flexible copper rod 22 is drawn upwardly from each tube 6 through the cooling chamber 12, where the rod is cooled by water sprays, and over the pulley 14, without fracture of the column 20 of molten copper protruding from the tube. WHAT WE CLAIM IS:-

1. A method of forming as a continuous process from molten metal a flexible elongate metal member which comprises causing molten metal contained in an upstanding tube to be ejected out of the open upper end of the tube whilst, at the same time, establishing about said open upper end an alternating electromagnetic field which sets up forces such as to cause the ejected metal to be compressed inwardly to form a column of molten metal which protrudes from the open upper end of the tube; cooling said column of molten metal to such an extent that at least an upper end part of the column is in a substantially solid state; and, whilst feeding molten metal into a lower part of the tube, withdrawing the substantially solidified part of the column of metal upwardly in the form of a continuous flexible elongate metal member.

thereto to form a continuous flexible elongate metal member.

3. A method as claimed in Claim 1 or 2, wherein, on emerging from the alternating electromagnetic field, the substantially solidified upper end part of the column and the succeeding flexible elongate metal member are subjected to a cooling medium.

4. A method as claimed in any one of the preceding Claims, wherein molten metal is caused to be ejected out of the open end of the tube by controlled continuous feeding of molten metal into a lower part of the tube.

5. A method as claimed in Claim 4, wherein molten metal is fed into the tube from a container of molten metal which is connected to but remote from the tube and which constitutes, in effect, the other limb of a U-tube.

6. A method as claimed in Claim 4, wherein molten metal is fed from a container into the lower end of the tube under controlled fluid pressure that is greater than atmospheric pressure.

7. A method as claimed in Claim 5 or 6, wherein the surface area of the molten metal in the container is substantially greater than the cross-sectional area of the tube.

8. A method as claimed in any one of the preceding Claims, wherein the flexible elongate metal member is in rod or wire form.

9. A method as claimed in any one of Claims 1 to 7, wherein the flexible elongate metal member being withdrawn upwardly from the tube is of a shape and size suitable for rolling down to rod form of smaller diameter or for drawing down into wire and wherein, in travelling from the tube to haul-off means, the cross-sectional area of the flexible elongate member is substantially reduced to that of rod or wire form.

10. A method as claimed in Claim 9, wherein the haul-off means, and if a rotatably driven guide roller or rotatably driven guide rollers is or are present the or each guide roller, are each driven at such a rotational speed that the linear speed of the flexible elongate member emerging from the upper end of the tube is substantially constant.

11. A method as claimed in any one of the preceding Claims, wherein the tube is substantially vertical.

12. A method as claimed in any one of the preceding Claims, wherein the metal is copper or copper alloy.

13. A method as claimed in any one of Claims 1 to 11, wherein the metal is aluminium or aluminium alloy.

14. Apparatus for use in forming a flexible elongate metal member comprising a container for molten metal; at least one upstanding tube open at its upper end and connected at or near its lower end to said container so that metal in said container can be forced into said tube for upward ejection from the open upper end of the tube; an electromagnetic inductor positioned around the open upper end of the tube, which inductor will establish about said open upper end an alternating electromagnetic field which will set up forces that will cause molten metal being ejected upwardly from said open upper end to be compressed inwardly to form a column of molten metal protruding from said open upper end; a cooling chamber housing means for producing sprays of cold air or water and so positioned with respect to the open upper end of the tube that said sprays will cool at least an upper end part of a column of molten metal being ejected from the open upper end of the tube; and means for withdrawing upwardly a substantially solidified part of said column of metal.

15. Apparatus as claimed in Claim 14, wherein, for initially cooling at least an upper end part of a column of metal and for withdrawing the column upwardly, a dummy member is provided which is of a shape and size suitable for bringing into contact with the upper end of a column of molten metal protruding from the open upper end of the or each tube and which is connected by a flexible line to haul-off means.

16. Apparatus as claimed in Claim 14 or 15, wherein, when the apparatus is in use, the source of molten metal is a container of molten metal remote from the tube or tubes and the lower end of the or each upstanding tube is connected to an outlet in the lower part of the container by a pipe, the or each tube, associated pipe and container, in effect, constituting a U-tube.

17. Apparatus as claimed in Claim 16, wherein two or more upstanding tubes are connected to outlets in the lower part of the container and separate means is associated with each tube for withdrawing upwardly a solidified part of the column of metal, said withdrawal means each being independently controllable.

18. Apparatus for use in forming a flexible elongate metal member substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

19. A method of forming as a continuous process from molten copper a flexible copper rod substantially as hereinbefore described with reference to the accompanying drawings.

20. A flexible elongate metal member made by the method claimed in any one of Claims 1 to 13 and 19.