GB1600519A

GB1600519A - Method of producing a plated extruded product

Info

Publication number: GB1600519A
Application number: GB2580878A
Authority: GB
Original assignee: Vereinigte Metallwerke Ranshoffen Berndorf AG
Current assignee: Vereinigte Metallwerke Ranshoffen Berndorf AG
Priority date: 1977-06-02
Filing date: 1978-05-31
Publication date: 1981-10-14
Also published as: CH628535A5; DE2823974A1; FR2392738A1

Abstract

In the method for the production of plated extruded products, a slug (2) provided with a compact outer jacket (3) of the plating material is extruded indirectly while cold or hot. It is also possible for the end face of the slug (2) facing the die (8) or the hollow ram (7) to have a layer (4), e.g. a disc, of the plating metal. <IMAGE>

Description

(54) METHOD OF PRODUCING A PLATED EXTRUDED PRODUCT (71) We, VEREINIGTE METALLWERKE RANSHOFEN BERNDORF AKTIENGESELLSCHAFT.

a Company organised under the laws of Austria, of: 4282 Braunau am Inn, (Upper Austria), 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 a method of producing a plated extruded product.

For the purposes of protection from corrosion, for providing a decorative surface or for providing particular possibilities of joining by soldering or the like it is often desirable for a metal material to be covered with another. While this is easily possible in the case of sheet metal, by rolling on the covering material, more serious difficulties are encountered in the case of extruded products, particularly when such products are produced by extrusion presses, as material displacements are caused by the die in the pressing operation, which disrupt an acceptable laminar coating.

According to the present invention, there is provided a method of producing a plated extruded product, in which a composite billet having a compact outer jacket and/or inner jacket of the plating material is placed in a movable extrusion container, which billet has a disc like coating of the plating material on an end face of the billet directed towards an extrusion die, and the billet is extruded in cold or hot condition through the die by displacement of the container relative to the die and hence displacement of the billet, via the disc like coating thereon, against the die.

In this method, the following known main advantages of the direct extrusion process are utilised: 1. No friction between the extrusion container wall and the billet surface. Thus a substantially lower extrusion force is necessary.

2. Full uniformity of the mechanical properties over the entire length of the extrusion. This uniformity depends on the flow behaviour in indirect extrusion. In this process the deformation region is very short. This does indeed suffer from the disadvantage that the billet surface enters 100% into the surface of the extrusion, but it is from precisely this fact that it is possible to deduce that, with this method, it must be possible to apply to a base material plating coating of a constant thickness.

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic illustration of the method of the invention utilised to form a solid extrusion, and Figure 2 is a schematic illustration of the method of the invention utilised to form a hollow extrusion or tube.

The method of the invention for producing a plated extruded product may involve, a) Production of an outer billet coating or compact jacket in the form of a tube which is extruded or welded from sheet metal, a deep-drawn or pressed cylindrical container with a bottom, or a metal sheet which is bent into a tubular configuration but which is not welded, of the desired thickness and with clean inner and outer surfaces in the tube (chemical or mechanical surface treatment).

b) Fitting a billet with clean outer surface and small clearance into the outer sleeve or jacket (possibly with the application of heat).

c) Heating the composite billet, which is conventional in hot extrusion processes (as rapidly as possible, in order to prevent oxidation of the engagement surfaces, or heating under a protective gas).

d) Extruding indirectly cold or hot, which process is diagrammatically illustrated by way of example in the drawings, for a solid extrusion in Figure 1 and for a hollow extrusion or tube in Figure 2.

As can be seen from the drawings, in the method of the invention a composite billet is inserted in an extrusion press container 1.

The billet comprises a core 2, for example of a high-strength alloy, and a compact outer jacket 3 of a plating material such as a corrosion-resistant alloy. At an end face directed towards the die 8, the billet has a disc-like coating 4, also of the corrosion resistant alloy. The container 1, and thus the composite billet, is moved in the direction indicated by the arrow 5, so that the plated extrusion 6 is extruded, by indirect extrusion through the hollow punch 7 which also carries the die 8. Figure 2 shows a similar operation of the method of the invention with the exception that the composite billet is perforated and has a mandrel 9 passing through its core 2. On the inside of the billet core 2, lying against the mandrel, is an inner jacket or tube of plating material, which forms a plating coating 11 on the inside of the tubular shaped extrusion 12 produced.A platen is shown at 13 in both Figures 1 and 2.

The method in the absence of the disclike coating 4 produces a plating coating of sufficiently constant thickness, over about 60 to 70% of the extrusion length. It will be understood that, in this operation, caused by the flow of material, there frequently occurs over-smearing of the plating layer by the core material. This smearing layer is in fact extremely thin, but nonetheless cannot be satisfactorily removed by mechanical surface treatment and/or etching. Expressed in a practical example, this means that an AlZnMgCul.5 shaped extrusion plated with AlMgSiO.5 has a very thin layer of AlZnMgCul.5 on the plating layer of AlMgSiO.5, and this reduces the advantages of the overall method.

This smearing effect can be prevented according to the method of the invention by inserting the disc-like coating 4 of the plating material, which is for example 5 mm in thickness, between the die and the end face of the billet core 2. When this is done, the method of the invention provides an acceptable plating coating of constant thickness, over 90% of the extrusion length.

This method of the invention makes it possible to produce plating whose adhesion quality cannot be impaired either by extreme reduction (for example from 25mm to 2mm diameter, with or without intermediate annealing), or by bending through small radii, by being bent backwards and forwards or heat treatment (for example hardening, soft annealing, etc.). The relationship between the thickness of the plating layer and the core diameter remains constant when reducing operations are performed.

Composite extruded products produced in this manner by the method of the invention can be used anywhere where a very high degree of strength must be combined with the best degree of corrosion resistance and/or adhesion (for example ski sticks, tennis rackets, bicycles, electrical conducting material, copper-aluminium soldering wires, mesh wires, and the like). In the case of tubes, plating can obviously be effected on the outside or on the inside surface, or on both surfaces.

WHAT WE CLAIM IS: 1. A method of producing a plated extruded product, in which a composite billet having a compact outer jacket and/or inner jacket of the plating material is placed in a movable extrusion container, which billet has a disc like coating of the plating material on an end face of the billet directed towards an extrusion die, and the billet is extruded in cold or hot condition through the die by displacement of the container relative to the die and hence displacement of the billet, via the disc like coating thereon, against the die.

2. A method of producing a plated extruded product substantially as hereinbefore described with reference to the accompanying drawings.

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

Claims

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

oxidation of the engagement surfaces, or heating under a protective gas).

d) Extruding indirectly cold or hot, which process is diagrammatically illustrated by way of example in the drawings, for a solid extrusion in Figure 1 and for a hollow extrusion or tube in Figure 2.

As can be seen from the drawings, in the method of the invention a composite billet is inserted in an extrusion press container 1.

The billet comprises a core 2, for example of a high-strength alloy, and a compact outer jacket 3 of a plating material such as a corrosion-resistant alloy. At an end face directed towards the die 8, the billet has a disc-like coating 4, also of the corrosion resistant alloy. The container 1, and thus the composite billet, is moved in the direction indicated by the arrow 5, so that the plated extrusion 6 is extruded, by indirect extrusion through the hollow punch 7 which also carries the die 8. Figure 2 shows a similar operation of the method of the invention with the exception that the composite billet is perforated and has a mandrel 9 passing through its core 2. On the inside of the billet core 2, lying against the mandrel, is an inner jacket or tube of plating material, which forms a plating coating 11 on the inside of the tubular shaped extrusion

12 produced.A platen is shown at 13 in both Figures 1 and 2.

The method in the absence of the disclike coating 4 produces a plating coating of sufficiently constant thickness, over about 60 to 70% of the extrusion length. It will be understood that, in this operation, caused by the flow of material, there frequently occurs over-smearing of the plating layer by the core material. This smearing layer is in fact extremely thin, but nonetheless cannot be satisfactorily removed by mechanical surface treatment and/or etching. Expressed in a practical example, this means that an AlZnMgCul.5 shaped extrusion plated with AlMgSiO.5 has a very thin layer of AlZnMgCul.5 on the plating layer of AlMgSiO.5, and this reduces the advantages of the overall method.

This smearing effect can be prevented according to the method of the invention by inserting the disc-like coating 4 of the plating material, which is for example 5 mm in thickness, between the die and the end face of the billet core 2. When this is done, the method of the invention provides an acceptable plating coating of constant thickness, over 90% of the extrusion length.

This method of the invention makes it possible to produce plating whose adhesion quality cannot be impaired either by extreme reduction (for example from 25mm to 2mm diameter, with or without intermediate annealing), or by bending through small radii, by being bent backwards and forwards or heat treatment (for example hardening, soft annealing, etc.). The relationship between the thickness of the plating layer and the core diameter remains constant when reducing operations are performed.

Composite extruded products produced in this manner by the method of the invention can be used anywhere where a very high degree of strength must be combined with the best degree of corrosion resistance and/or adhesion (for example ski sticks, tennis rackets, bicycles, electrical conducting material, copper-aluminium soldering wires, mesh wires, and the like). In the case of tubes, plating can obviously be effected on the outside or on the inside surface, or on both surfaces.

WHAT WE CLAIM IS: 1. A method of producing a plated extruded product, in which a composite billet having a compact outer jacket and/or inner jacket of the plating material is placed in a movable extrusion container, which billet has a disc like coating of the plating material on an end face of the billet directed towards an extrusion die, and the billet is extruded in cold or hot condition through the die by displacement of the container relative to the die and hence displacement of the billet, via the disc like coating thereon, against the die.
2. A method of producing a plated extruded product substantially as hereinbefore described with reference to the accompanying drawings.