RU2561564C1 - Method of producing of bimetallic wire - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: bimetallic work piece is fabricated by tape wrapping of the core and connecting of tape edges. In the core V-shaped cutting with depth no more than a half of diameter of the core and an angle 30-60° is made in advance and the core is levelled to get a rectilinear form along its length, then tape edges are inserted into V-shaped cut and the work piece is compressed, eliminating the cut. The tape width is regulated by mathematical expression.

EFFECT: avoidance of welding use, as a result, no heating and fusing of edges and the core, occurrence of intermetallic compounds reducing the strength of connection of components at cladding.

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Description

The invention relates to the processing of metals by pressure, namely the production of bimetallic wire.

There are many known methods for the manufacture of bimetallic wire, consisting of various metals and alloys.

A known method of manufacturing a wire by pouring liquid metal into a metal rod mounted in a cylindrical mold (Dmitrov L.N., Kuznetsov E.V., Kobelev A.G., Chegodaev Yu.P., Shklyaev V.E., Wojciechowski V.A. Bimetals, Perm Book Publishing House, 1990). After solidification of the metal, the resulting billet with a diameter of 50-100 mm is processed by various rolling methods. First, hot rolling is brought to diameters of 10-12 mm, and then, using various processes of cold rolling and drawing, a wire of the required size is obtained. A significant disadvantage of this method of producing wire is its significant complexity.

A known method of manufacturing a steel wire with a coating, mainly with a thick coating, from a softer metal (RU 1808434, B21C 1/00, publ. 15.04.1993). The method includes cleaning the contact surfaces of the shell and the core, forming a shell around the core by extruding the core of the shell metal from the profile with a width equal to the width of the bimetallic billet and a height not less than 2.3 times the thickness of the shell in the bimetallic billet. Moreover, the extrusion process is carried out at a ratio of the yield strengths of the core metal and the sheath not less than 20 (σ _tf / σ _tob > 20). After the formation of the shell, it is welded.

The disadvantages of this method are obvious. In order to provide the desired ratio of the yield strengths of the core metal and the sheath, it is generally necessary to use sheath heating. For example, for the manufacture of steel-copper wire, the copper sheath is heated to 850 ° C. To prevent the oxidation of copper and steel, it is necessary to use a protective gas in the process of forming the shell.

Since the shell is riveted in the process of obtaining a bimetallic billet, its strength characteristics increase and ductility decreases, the obtained billet must be annealed. And only after that use rolling or drawing methods to obtain the required wire sizes. This method of producing bimetallic wire is not technologically advanced, rather laborious and limited in application. So, for example, in this way it is impossible to obtain an aluminum-copper bimetal wire.

A known method of manufacturing a bimetallic wire, providing a continuous process for its production (RU 124405, V23K 20/04, publ. 01.01.1959).

The starting material for the manufacture of bimetallic wire is a steel core (bar) or steel wire and non-ferrous metal tape. The implementation of the method is ensured by the use of sequentially arranged mechanisms, starting from the wire feed mechanism (unwinder) to the receiving device (winder).

Rolled wire and tape pass through the butt welding machines, loop devices and enter the molding mill. In the forming mill, the tape is formed into a tube billet, into which a steel wire (rod) is simultaneously molded. Welding of a longitudinal seam is carried out in a high-frequency welding machine. The upsetting of the edges in this case is carried out by two crimp rollers with vertical axes. After high-frequency welding, the bimetallic billet is deformed in the reduction mill, and then in the calibration mill, in which the final crimping is carried out, bringing the dimensions to the required in the finished product. From the calibration mill, the wire enters the receiver.

The disadvantage of this method is the presence of high temperature in the zone of high-frequency welding, the need to remove the resulting weld bead. This method of producing bimetallic wire practically does not allow it to be used in the manufacture of bimetallic aluminum-copper wire.

When using copper as a cladding material during its welding at a temperature of 1050 ° C, the aluminum rod can melt, the melting point of which is 650 ° C. In addition, in the high-frequency welding zone, as a rule, strong and brittle intermetallics are formed, which prevent the formation of a durable welded joint of an aluminum rod with a copper strip during the reduction process.

Closest to the claimed is a method of manufacturing a bimetallic wire (RU 2095169, B21C 1/00, publ. 10.11.1997), in which a bimetallic tape with a double-sided coating of the sheath metal is taken as a workpiece, the tape is cut along circular shears along circular shears, the sheath is formed on the wires by rolling them. First, a groove is made on the faces of the wire that are not coated, i.e. on the side surfaces of the wire, and then bend its edges simultaneously until they are tightly connected to each other. Next, wire drawing is carried out to obtain the required size. The method eliminates the use of various methods of electric welding when forming the shell.

The disadvantage of this method is the lack of technology, despite the apparent simplicity. A rather serious problem is the operation of the dissolution of the workpiece (bimetallic tape) on individual wires and their further processing. Each wire after cutting should have its own production line, which consists in shaped rolling, molding, subsequent drawing and winding on a drum coiler. The operation of the lines must be coordinated. What is the use of complex control systems for? The process of making grooves on the uncovered side surfaces of the wire is difficult to perform and requires the use of fairly sophisticated equipment. In addition, the drawing process is accompanied by wire breaks, tool wear. To eliminate gaps and replace the tool, it is necessary to stop the units, which significantly reduces productivity.

The invention solves the problem of ensuring the manufacturability of the manufacturing process of bimetallic wire.

This is achieved by the fact that in the method of manufacturing a bimetallic wire, including obtaining a bimetallic billet by wrapping the core with tape and connecting the edges of the tape, subsequent rolling and drawing, according to the invention, a V-shaped cut is made in the core beforehand with a depth of not more than half the core diameter and an angle of 30-60 ° and the core is edited to give it a straight shape along the length, then the edges of the tape are tucked into a V-shaped cut and the workpiece is compressed, eliminating the cut, while the tape width is determined by the expression

B = P + 2H,

where Π is the perimeter of the cross section of the core,

Η is the depth of the V-shaped incision.

Performing a V-shaped cut in the core allows you to get a bimetallic billet without the use of various types of electric welding.

The depth of cut should not be more than half the diameter of the core, otherwise the uneven deformation of the core, its curvature in the longitudinal direction, and the deformation force increase.

If the angle of incision is less than 30 °, then, as experiments show, the operation of filling the edges of the tape into a V-shaped incision of the core is much more complicated. If the insertion angle is more than 60 °, then the insertion forces and subsequent compression of the bimetallic workpiece are significantly increased to eliminate the insertion.

When performing a V-shaped cut, the rod is bent, therefore, before performing the operation of wrapping a bar or wire with a tape, it must be straightened by editing, for example, in roller devices.

Eliminating the cut by compressing the workpiece along its perimeter provides a snug fit with the core tape wrapped.

The choice of the width of the tape is due to ensuring guaranteed coverage of the core by the tape and retaining the edges of the tape in a V-shaped cut during subsequent deformation.

The technical result is a tight fit of layers of different metals to each other without the formation of intermetallic compounds.

The invention is illustrated by drawings, which show the steps of forming a bimetallic billet: in FIG. 1 - core with a V-shaped insert, in FIG. 2 - core with a tape, the edges of which overlap a V-shaped cut, in FIG. 3 - core with a tape, the edges of which are tucked into a V-shaped insert, in FIG. 4 - bimetallic billet with a rod and compressed edges of the tape.

Position 1 denotes the core, position 2 - tape.

The method is as follows.

Use raw materials, such as a metal bar or wire and tape. A V-shaped incision is made as shown in FIG. 1. The depth of the V-shaped cut is not more than half the diameter of the rod. Then the rod or wire is straightened, which is provided by editing in 5-7 roller devices.

After editing, the rod is wrapped with tape so that the edges of the tape are above the V-shaped cut and overlap it (Fig. 2), forming an overlap of the tapes. The value of this overlap should be no more than the depth of cut.

After wrapping the rod with tape, the edges of the tape are pressed into a V-shaped cut (Fig. 3) and then the edges of the tape are brought together until they touch (Fig. 4).

At the final stage, the workpiece is compressed until the cut is eliminated.

Thus, a bimetallic billet is obtained.

Example.

The following materials were used to obtain bimetallic wire: annealed aluminum wire from AD31 alloy with a diameter of 6.5 mm and annealed copper tape from an alloy with a thickness of 0.2 mm.

A V-shaped insert was made in the wire, having an angle at the apex of 45 °. For this, a two-roll working stand was used, having work rolls with a diameter of 60 mm. The depth of cut is 2.5 mm. Used copper tape M1 wide

B = πD + 2Η = 3.14 × 6.5 + 2 × 2.5 = 25.41 mm,

where D is the diameter of the wire,

Η is the depth of the V-shaped incision.

The width tolerance of the tape according to GOST 1173-73 is 0.4 mm.

After the V-shaped cut was made, the wire was fed into a 7-roller straightening machine having roller diameters of 70 mm. Then the wire was stripped in a stripping wire machine. In a similar stripping machine, both surfaces of the copper strip were stripped.

After stripping the wire and copper tape on the forming unit, the wire was wrapped with copper tape so that the edges of the tape went into a V-shaped insert. The filling of the edges of the tape into a V-shaped cut is provided in a molding mill having, for example, 6-7 pairs of profiled rollers. Then, the edges of the tape were compressed until they touched by drawing in a die with a diameter of 6.9 mm.

Thus, a bimetallic billet was obtained (Fig. 4).

The prepared bimetallic billet with a diameter of 6.9 mm was further deformed in a 4-roll caliber. When rolling in a 4-roll gauge, a square wire was obtained, which was then drawn through a roller die, and then through a monolithic die. After pulling the bimetallic wire four times through the monolithic die, a round bimetallic wire with a diameter of 3.0 mm was obtained.

The deformation of a bimetallic wire in a 4-roll gauge and roller dies and subsequent drawing in monolithic dies ensures a strong connection of the copper tape and aluminum wire.

After heat treatment of a bimetallic wire with a diameter of 3.0 mm in a broaching furnace on a drawing mill with monolithic dies, a wire with a diameter of 1.0 mm was obtained. The surface of the wire was obtained without violating the continuity of the copper tape, the thickness of the copper layer in the wire of 1.0 mm was 30 μm.

The advantage of this method is that it does not require the use of various welding methods based on the use of electrical energy and heating the edges of the cladding tape. This eliminates the heating of the edges, their fusion, there are no devices for removing the burr, which is formed during electric welding. The core metal does not melt when metals having a low melting point (aluminum, zinc, lead) are used as the base. Intermetallic compounds do not appear during the process of wrapping the rod with a tape, which reduce the strength of the components when clad.

The invention provides the manufacturability of the process for producing bimetallic wire.

Claims (1)

A method of manufacturing a bimetallic wire, including the formation of a bimetallic billet by wrapping the core with tape and connecting the edges of the tape, subsequent rolling and drawing, characterized in that a V-shaped cut is made in the core with a depth of not more than half the core diameter and an angle of 30-60 ° and the core is edited to give it a straight shape along the length, and then the edges of the tape are tucked into a V-shaped cut and the workpiece is compressed until the cut is eliminated, while the width of the tape B is determined by the expression:
B = Π + 2H,
where Π is the perimeter of the cross section of the core,
H is the depth of the V-shaped incision.

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