WO1998038005A1

WO1998038005A1 - Method of producing wire-shaped welding electrodes made of metals and/or alloys and wire-shaped welding electrode

Info

Publication number: WO1998038005A1
Application number: PCT/EP1998/000885
Authority: WO
Inventors: Volker Müller; Hans Sommer; Ulrich Finger
Original assignee: C.M.T.M. Dr. Müller Verfahrenstechnik Gmbh
Priority date: 1997-02-28
Filing date: 1998-02-17
Publication date: 1998-09-03
Also published as: EP0964769A1

Abstract

The invention concerns a method of producing wire-shaped welding electrodes made of metals and/or alloys, and a welding electrode produced according to this method. According to the invention, the method proceeds from a composite wire which consists of a drawable closed outer jacket which is a good conductor and of a core which can be cold-formed well. The jacket is produced by a cleaned metal strip which is continuously shaped to form a pipe whilst receiving the core. The residual longitudinal seam is closed by a conventional welding process without welding additives. The core can consist of one or a plurality of compact wires (5, 6) and/or of a laminated composite wire (3, 6) comprising a plurality of metals or alloys in layers. The jacket (1) and core (3, 5, 6) are shaped to form a mechanically plated laminated composite wire by subsequent common drawing. Owing to the mechanical plating of the components, the laminated composite wire behaves in the same manner as a compact material during further processing.

Description

Process for the production of wire-shaped welding electrodes consisting of metals and / or alloys, as well as wire-shaped welding electrodes

Description :

The invention relates to a method for producing wire-shaped welding electrodes consisting of metals and / or alloys, and to a wire-shaped welding electrode produced by such a method.

For the increasing automation of welding processes, it is necessary that the necessary welding consumables are made available in wire form. For precision welds wires must be small ^"diameter available. In various alloys, however, the production of wire in known drawing methods due to the material properties of the alloy is not possible or only with increased efforts. This applies, for example, aluminum bronzes with aluminum contents greater than 8 percent by mass. Low electrical conductivity and high contact resistance of alloys due to unavoidable oxide layers also lead to premature glow and / or a decrease in the arc intensity when welding with self-consuming electrodes. This will

Welding in lower layers with larger wall thicknesses and even welding through with thin walls is made difficult or impossible.

Various methods for producing self-consuming welding electrodes from several material components have already been proposed for the overlay and joint welding of such critical alloys. A common feature of these known processes is that the alloys in the required composition only form when the electrodes are melted.

For example, DE 31 28 640 AI shows a welding wire for use as an electrode, which consists of several individual wires twisted together. Anyone who used there

Single wires contain different metallic components or materials. In addition, a core wire can be provided, around which the individual wires are wound helically.

The for the production of the welding electrode wire according to DE

31 28 640 AI necessary procedures have significant disadvantages. It is therefore not possible to produce smaller wire diameters by pulling, since the lubricant required for the pulling process penetrates into the spaces between the individual wires during pulling and cannot then be removed or only with considerable effort. In addition, the arc does not burn uniformly in the case of an electrode shape formed in this way, since the radially different and variable distribution of the components results in different electrical and / or magnetic properties, which lead to undesired current density variations. For the reasons mentioned above, welding errors result when the known welding electrode wire is used. In the method for producing an electrode from different metals and / or alloys in accordance with the teaching of DE 23 59 738 A1, a plated strip is formed into a roll, the intermediate product thus produced subsequently opening up. the required diameter is drawn. The solution described there has the disadvantage that the outer surface of the electrode is not closed, so that lubricant penetrates into the existing gap when pulling, which lubricant cannot be completely removed, as a result of which welding errors are the result in later use. Other solutions described in DE 23 59 738 AI, such as the wrapping of one or more core wires, have the common disadvantage that the electrodes produced in this way cannot be pulled, so that it is impossible to produce wires with smaller diameters under economical conditions.

In addition, so-called cored wires are known in welding technology for self-consuming electrodes. For the production of electrodes from alloys that are particularly difficult to subject to cold or hot working, e.g.

Nickel or cobalt-based alloys, DE 35 42 663 AI describes a filler metal and a process for its production in which inert gas atomized powder is poured into a seamless tube and then the powder is compacted by pulling, thereby further including the enclosed one Gas quantity should be reduced.

The tube is not filled continuously, but the powder is poured into a tube wound on a reel with mechanical movement, ie shaking. With the method briefly cited above, it cannot be ensured that the tube can be filled uniformly. Further disadvantages are the high outlay “for the production of the metal powder and the inevitable entrapment of gas inside the electrode. The trapped air can be removed before being drawn and replaced by a protective gas, but only the type of trapped gas changes. PCT WO 86/03716 describes a method for producing welding wire. There it is proposed to form a metal strip into a sheath around a core, which consists of powder and / or solid wires, the diameter then being reduced by pulling, rolling or hammering, in order to form a metal composite at the same time. According to the teaching there, powder is always introduced into the core in order to achieve a bond between the sheath and core wires during drawing. The economy of the known method is limited by the fact that the cored wires can only be drawn with small degrees of deformation and, as a result, a relatively small diameter of the band formed into the sheath must already be assumed. So that the solution described in the above teaching is not suitable to eliminate the disadvantages according to DE 35 42 663 AI.

Overall, it remains to be ascertained that the welding electrodes produced according to the known methods were only able to assert themselves in welding technology for special or technical reasons. There is therefore still a considerable need for widely usable solutions for self-consuming electrodes which consist of a composite of several metals and / or alloys in wire form and which can also be drawn to small diameters for conceivable applications.

It is therefore an object of the invention to provide a method for producing wire-shaped welding electrodes made of metals and / or alloys, which allows a wide variety of material components to be joined to a laminated wire in such a way that the intermediate products formed in this way are not suitable for treatment on a Wire drawing system have disadvantageous properties. In addition, it is an object of the invention to provide a universally applicable wire-shaped welding electrode that can be manufactured in very different diameters.

The object of the invention is achieved on the process side with a teaching according to the features of patent claim 1 and with a wire-shaped welding electrode according to the features of claim 7, the subclaims comprising at least expedient refinements and developments.

According to the most important basic idea of the invention, the method for producing the wire-shaped welding electrode uses a layered composite wire, which has a closed outer surface.

The laminated wire is produced by first continuously forming a metallic, brightly cleaned strip into a tube and welding it by a conventional welding process without a filler metal. TIG, plasma, induction or laser welding can be used as the welding process. Before welding, the pretreated, bare metal core is continuously introduced into the pipe, which has not yet been completely finished, this core consisting of one or more compact wires and / or one

Laminated wire can consist of several metals or alloys. By subsequent forming together, e.g. by pulling or rolling, the sheath and core are mechanically plated to form the composite wire. The composite wire thus produced can then be drawn to the required final dimensions in a conventional manner. At the latest when this pulling takes place to the desired diameter, a mechanically plated layered composite material or layered composite wire is formed, which can be optimized with regard to the materials of the core and jacket with regard to the processability and the desired welding applications.

In a process-related embodiment of the invention, the core is provided with at least one longitudinal groove which can be formed by rolling in, each longitudinal groove serving to accommodate an insert wire. Core and insert wire materials Lines can have different properties and / or different material compositions.

In a preferred embodiment of the invention, the longitudinal groove in the core essentially has a width which corresponds to the diameter of the insert wire. The depth of the longitudinal groove is in a range from 0.7 to 1.0 times the diameter of the insert wire. The core described above with a longitudinal groove and insert wire can be provided with an inner sheath or an inner sheath, which is then surrounded by the outer sheath, the outer sheath forming the above-mentioned welded tube with an outer closed surface. When pulling the composite wire prefabricated in this way, the desired cladding is carried out by connecting the insert wire and the longitudinal groove core as well as the outer and inner sheath and core.

According to the method, the core can be prefabricated as a composite wire with an open or closed outer surface that forms the inner shell, for this purpose a core wire made of a first metal or a core with a longitudinal groove and insert wire made of different materials with a sheath that forms the inner shell , be surrounded. The inner shell is made of a second metal. The inner jacket can in turn be formed from a prefabricated, multi-layer plated band.

The wire-shaped welding electrode made of metals and / or alloys according to the invention thus represents a laminated wire with an outer sheath made of ductile material closed by welding and a core which can be formed in the inside of the sheath. The outer sheath preferably consists of copper or copper alloys , wherein the core is a composite material that can be produced by the above method.

Depending on the alloying behavior, the alloying elements required for the overall composition are either in the base material is alloyed (e.g. nickel, tin or manganese in copper) or integrated as individual components (e.g. aluminum or iron). For example, the core can be constructed according to the invention as a composite wire which, for example, consists of a sheath made of aluminum (aluminum alloy) and a core which, in addition to copper, contains further alloy elements such as Fe, Ni, Mn, Sn etc. The Al sheath of the composite wire used as the core is formed from tape, the tape edges either being welded or remaining unwelded. It is formed by either wrapping the tape spirally around the core or by profiling it into a tube with a longitudinal seam. Since the alloying of copper with Fe contents greater than 2 mass percent is practically no longer possible, an iron wire (steel wire) is integrated into the core in these cases.

In summary, the electrodes consist of different material components that are built up as a composite wire with a closed outer surface. The composite wire contains an electrically highly conductive and pullable closed outer sheath and a good cold-formable

Core. The composition and structure of the sheath and core are selected so that the mechanical properties required in the manufacture of the wire-shaped welding filler, on the one hand, and optimal properties in the application and the desired properties of the alloy after melting, on the other hand, are ensured.

The decisive advantage over the prior art is that the outer jacket of the wire-shaped welding electrode is closed, so that no lubricant can get into the individual material components or the gaps between them during subsequent pulling, so that a high degree of uniformity is achieved and the inclusion of gases is completely avoidable. Due to the mechanical plating of the components, the laminated wire behaves like a compact, quasi-monolithic material during further processing, particularly by drawing and / or rolling. The invention will be explained in more detail below with the aid of exemplary embodiments and with the aid of figures.

Here show:

1 shows a cross section through the core introduced into the jacket welded as a tube before plating;

2 shows a cross section through the wire-shaped welding electrode after the plating in a first drawing step;

3 shows a cross section through the wire-shaped welding electrode with a core, unwelded inner and welded outer jacket after the plating;

4a and 4b a core cross section with a longitudinal groove before and after inserting an insert wire;

Fig. 5 shows a cross section through a wire-shaped welding electrode with insert wire and unwelded inner and welded outer jacket after plating and

6a and 6b the formation of an inner unwelded

Cladding made of a clad composite material before and after wrapping with a welded outer sheath.

Alloys with at least 70% by mass of copper, 5 to 18% by mass of aluminum and other alloying elements such as Fe, Ni, Mn and Sn are of essential technical importance in welding technology. so-called aluminum composite bronze. Due to their mechanical properties, these find an increasingly broad field of application. With increasing aluminum content, however, the cold formability of these alloys. The production of wire from such an alloy by drawing is then practically no longer possible. For this reason, according to the exemplary embodiment, the welding electrode for aluminum multi-material bronze with higher AI contents is constructed from different material components in such a way that, on the one hand, it is cold-formable and, on the other hand, the required alloy compositions result when the electrodes are melted.

The individual components are selected and combined according to the required processing and usage properties.

In a preferred exemplary embodiment, the aluminum bronze welding electrodes are produced as composite wires in that, as shown in FIGS. 1 and 2, a core 2 is sheathed with copper or a copper alloy to form a jacket 1. The jacket 1 guarantees good ductility with optimal electrical conductivity and a low contact resistance. The core itself can be a composite (e.g. 3 and 4 in Fig. 3).

Depending on the alloying behavior, the alloying elements are either alloyed into the base material, e.g. nickel, tin or manganese in copper, or quasi mechanically integrated as individual components, e.g. aluminum or iron. For example, the core itself, as shown in FIG. 3, can be constructed as a composite wire which contains, for example, a core material 4 which, in addition to copper, has further alloy elements such as Fe, Ni, Mn or Sn. This core material 4 is then surrounded by an inner jacket 3 made of aluminum or an aluminum alloy. The aluminum sheath 3 of the composite wire used as the core is formed from a strip, the strip edges either being welded or remaining unwelded. The jacket 3 is formed by either winding the tape spirally around the core 4 or profiling it into a tube with a longitudinal seam.

Since the alloying of copper with Fe contents greater than 2 mass percent is practically no longer possible, there is the possibility with reference to FIGS. 4a, 4b and 5 to introduce an iron or steel wire into a corresponding longitudinal groove 9 of the core 6. FIG. 4a shows the design of the longitudinal groove 9, with FIG. 4b then showing the state after the insertion wire 5 has been received in the longitudinal groove 9 of the core 6.

In the cross-sectional representation of a welding electrode wire according to FIG. 5, a core 6 with an insert wire made of iron or steel 5 is thus assumed, an inner sheath 3 made of e.g. Aluminum or an aluminum alloy is provided. This structure is then surrounded by the outer jacket 1, which has a closed surface.

The composition of the jacket 1 and the structure of the composition of the core 2 depend in each case on the desired alloy composition. In this way, a plurality of insertion wires 5 can also be molded into the core wire 6.

In addition, the core 8 can, as shown in FIGS. 6a and 6b, be encased by a plurality of cladding layers 7. The multilayer jacket 7 of the core 8 is formed in this case by forming a previously plated band.

In the exemplary embodiment illustrated in FIG. 3, aluminum bronze welding electrodes with a composition of 14 to 15 mass percent aluminum, 2 mass percent manganese, 1.5 mass percent iron, 2.5 mass percent nickel and the rest copper are assumed. The outer welded sheath 1 with a volume fraction of 24% and the core 4 with a volume fraction of 39.3 to 41.2% consist of a copper alloy with 2.35 mass percent manganese, 1.7 mass percent iron and 2.94 mass percent nickel. In between is a Aluminum jacket 3 with an open longitudinal seam, which has a volume fraction of 34.8 to 36.7%.

The welding wire shown in FIG. 5 represents an aluminum bronze e-welding electrode with a composition of 14 to 15 percent by mass aluminum, 3 to 5 percent by weight iron and a remainder copper. As described, the first step is to illustrate with FIGS. 4a and 4b , A core wire 6 is used, which consists of copper, into which the longitudinal groove 9 is rolled. The width of the longitudinal groove is approximately equal to the diameter of the iron insert wire 5, the depth of the longitudinal groove 9 corresponding approximately to 0.9 times the diameter of the insert wire 5. The insertion wire 5 is then rolled into the core 6 in a form-fitting manner. The copper core wire 6 has a volume fraction of 35 to 39%, the iron wire 2.5 to 4.3 volume percent. Then there is the aluminum jacket 3 (FIG. 5) with an open longitudinal seam and a volume fraction of 34.8 to 36.7 volume percent. The longitudinally welded, closed outer jacket 1 consists of copper and has a volume fraction of 24 volume percent.

Claims

claims

1. A process for the production of wire-shaped welding electrodes made of metals and / or alloys as composite wire with a closed outer surface, whereby in a continuous process a well-conductive, ductile metallic strip is formed into a still open tube, a metallic, cold-formed tube inside the tube. insertable core and the tube to a closed

Sheath is welded, and after the welding of the tube by pulling the sheath and core together to a desired diameter, the mechanically plated laminated wire is formed, characterized in that one or more longitudinal grooves are rolled into the core to accommodate a or more insert wires are used, wherein core and insert wire materials have different material compositions, and that the metallic strip before the tube forming and the core are subjected to a surface cleaning treatment before insertion into the tube.

2. Process for the production of wire-shaped welding electrodes made of metals and / or alloys as composite wire with a closed outer surface, whereby in a continuous process a highly conductive, ductile metallic strip is formed into a still open tube, a metallic, cold-formed tube inside the tube. insertable core and the tube to a closed

Sheath is welded, and after the welding of the tube by pulling the sheath and core together to a desired diameter, the mechanically plated laminated wire forms, characterized in that the core is prefabricated as a composite wire with an open or closed outer surface, whereby for this purpose, a core wire made of a first metal or a core with a longitudinal groove and insert wire made of different materials a multi-layer jacket made of different metals is encased.

3. The method according to claim 1 or 2, characterized in that the width of the at least one longitudinal groove substantially the diameter of the insertion wire and the depth of the longitudinal groove is substantially in the range of 0.7 to 1.0 times the diameter of the insertion wire .

4. The method according to claim 2, characterized in that the multilayer jacket is formed from a prefabricated multilayer plated band.

5. Wire-shaped, made of metals and / or alloys welding electrode, consisting of a composite wire with an outer closed by welding sheath (1) made of drawable material and an inside of the sheath (1) arranged cold-formable core (2), characterized in that the outer jacket (1) consists of copper or copper alloys and the core (2) consists of copper or a copper alloy (4) with iron and / or nickel and / or tin and / or manganese and / or a mechanically integrated aluminum component with a percentage by mass of ≥ 7.5 and / or a mechanically integrated iron component with a mass percentage of ≥ 1.5.

6. Wire-shaped welding electrode according to claim 5, characterized in that the core (6) at least one longitudinal groove (9) for receiving at least one insertion wire (5) made of iron or iron alloys and / or an inner jacket (3) made of aluminum based on the overall arrangement or an aluminum alloy.