RU2378093C1 - Electrode of machine for contact welding of strips by melting - Google Patents

Abstract

FIELD: welding works.

SUBSTANCE: invention may be used in contact butt welding of strips in continuous metallurgical units, for instance in etching lines or units of longitudinal cutting, which mostly process strips of high-carbon steels. Grip joined to feed bar is equipped with conductor insert arranged as front relative to axis of welding and back pressing plank. Conductor insert is arranged with semicircular groove, which is parallel to side end of insert. Conductor element is installed in groove and interacts with it. Its flat surface is arranged as protruding over insert surface by value of at least 0.3 mm. Distance from side end of insert to beginning of semicircular groove makes 2…4 mm. Conductor element is produced by installation of annealed copper wire bar in semicircular groove and its further deformation for arrangement of flat surface.

EFFECT: improved quality of welded butt by provision of even heating of welded joint along its length with simplification of machine design for contact welding.

3 cl, 4 dwg

Description

The present invention relates to welding production, and in particular to devices for flash butt welding of strips operating in continuous metallurgical units, for example, pickling lines or slitting units, which process mainly strips of high carbon steels.

The welded joints of strips of high carbon steels, due to high cooling rates after welding, are intensively hardened, become brittle and unsuitable for transportation through the unit, and often collapse immediately at the exit of the welding machine. Therefore, in welding machines, heat treatment of welded joints is provided immediately after welding directly in the lips of the welding machine by heating with current from the welding transformer. However, due to the irregular cross-section of the strips (for example, concavity or convexity obtained by hot rolling) and the presence of an uneven scale of scale on the surface of the strips, the joints are heated unevenly and their quality after heat treatment is not the same in length, which can also cause their destruction during the processing of welded strips .

A known complex for flash butt welding of the ends of strips of the KSO-32 01 type, manufactured in series, for joining strips up to 500 mm wide in continuous metallurgical units (see Passport 3YUR 942.163 PS and 3YUR 942. 152 PS, album 1, Pskov, 1976 g), providing welding and heat treatment in the jaws by passing current through the weld zone.

However, the current-carrying inserts made of bronze on the jaws of this complex do not provide uniform current supply to the strips due to deviations from the correct geometry of the cross section of the strips and the presence of an uneven scale on the hot-rolled strips.

It is known that to ensure uniform current supply to the strips, it is recommended that the electrodes of butt machines with current-carrying inserts of copper be made (see, for example, N. S. Kabanov. “Welding on Contact Machines”, M .: Higher School, 1979, p. 36) . At the same time, it is proposed to perform beveling on the front surface of the insert adjacent to the strip and facing the welding axis, to provide local current supply in the form of a strip 2 mm wide.

The main drawback of this proposal is that the current lead strip wears out very quickly during the operation of the machine due to the high clamping and draft forces during welding, and the electrode fails and needs to be replaced, so the current-carrying inserts are most often made of highly conductive and wear-resistant bronze.

A known machine for flash butt welding of strip ends / ed. testimonial. SU No. 1146162 A1, cl. MKI V23K 11/04, 03/23/1985 /, containing a welding transformer, beds with clamping jaws placed in them, provided with electrodes connected to busbars, equipped with busbars and mounted to move towards each other, equipped with elastic conductive elements installed between the clamps jaws and electrodes, and the clamping jaws are flexible in the direction of movement in the form of bimetallic springs.

The disadvantage of this machine is that the elastic conductive elements limit the flow of current during heat treatment, heat up and fail, and when welding strips of the maximum cross section, the elastic conductive elements do not provide reliable clamping of the strips for the implementation of the necessary allowances for upsetting, which leads to a shift of the strips at the junction in height, in addition, the design of the clamping unit is difficult to configure, which does not allow it to operate reliably.

The technical result of the proposed solution is to improve the quality of the weld by ensuring uniform heating of the weld along the length during heat treatment, simplifying the design of the machine.

The technical result with the achievement of the above effect is ensured by the fact that the electrode of the machine for flash welding of fusion strips, containing a sponge connected to the busbar with a frontal relative to the welding axis current-carrying insert and a rear clamping bar, the current-carrying insert is made with a semicircular groove parallel to the side end of the insert, axis which is located on the plane of the insert adjacent to the strip, while a current-carrying element is installed in the groove with an excess of its plane over the adjacent to the elk insertion plane by an amount not less than 0.3 mm and interacting with the surface of the groove, wherein the groove is set current-carrying element of annealed copper wire, the diameter of which is determined depending on

,

,

where D is the diameter of the semicircular groove, mm,

h is the excess of the plane of the current-carrying element over the surface of the insert, mm,

and the axis of the groove is located from the lateral end of the current-carrying insert at a distance

L = 1 / 2D + e (mm),

where D is the diameter of the semicircular groove, mm;

e is the distance from the side of the electrode to the beginning of the semicircular grooves - 2 ... 4 mm.

The electrode of the machine for flash welding of strips by fusion is shown in figures 1, 2, 3, 4, where:

- figure 1 schematically shows the inventive electrode of the machine for resistance welding of fusion strips after installation in the groove of a copper rod,

- figure 2 schematically shows the inventive electrode of the machine for resistance welding of fusion strips after installation in the groove of a copper rod and crimping the rod,

- figure 3 is a view along arrow A in figure 1 (the dotted line indicates the place of the bar in the groove),

- figure 4 is a view along arrow A in figure 2.

The electrode of the machine for flash welding of fusion strips contains a sponge 1 connected to the busbar 2, with the front relative to the axis of welding of the current-carrying insert 3 and the rear clamping plate 4, the current-carrying insert 3 is made with a semicircular groove 5 parallel to the side end, the axis of which is located adjacent to the strip of the plane 6 of the insert 3, while a current-carrying element 7 is installed in the groove 5, which interacts with the surface of the groove 5 and exceeds the plane of the plane 6 of the insert 3 adjacent to the strip by at least its 0.3 mm, the current-carrying member 6 is made of an annealed copper wire, the axis of the groove 5 is provided on the end side a conductive insert 3 at a distance greater than half its diameter is 2 ... 4 mm.

The electrode of the machine for resistance welding of fusion strips works as follows. Before starting the operation of the machine for welding strips of high carbon steels, electrodes with semicircular grooves 5 are made on the current-carrying busbars 2 of the movable and stationary frame 5. The grooves 5 of the annealed copper wires are installed in the grooves 5 of the required length (protruding beyond the edges of the insert). The diameter of the wire is calculated according to the dependence of the diameter of the groove 5 and obtaining the necessary excess of the current-carrying element 7 over the plane 6 of the insert 3 adjacent to the strip.

An example of execution: when the diameter of the groove is 5 mm and the plane of the current-carrying element is higher than the insertion plane of 3 mm, the diameter of the bar will be

After installing the rods in the grooves, the electrodes are clamped, while the part of the rod protruding from the groove 5 is deformed, the metal of the rod completely fills the groove 5, and its excess provides a flat excess of the conductive element 7 over the plane 6 of insert 3. After squeezing the electrodes, strips are fed for welding, followed by heat treatment joints. When the strips are clamped, the current-carrying element 7 protruding above the plane 6 is uniformly pressed against the strip, takes the form of its surface and provides a uniform current supply across the entire width of the strip.

The semicircular groove 5 is performed by milling or planing, the second method is preferable, since the longitudinal risks from the cutter that are formed when planing are filled with metal of the rod and this helps to keep the current-carrying element 7 from displacement when the strips are accidentally exposed to it. The protruding ends of the rods can also be additionally secured with clamps at the edges of the inserts 3.

During operation of the machine (after performing a certain number of welds with heat treatment of the joints), with a noticeable decrease in the uniformity of heating of the joints between the welds, the current-carrying element 7 is replaced, performing the operations described previously.

The proposed electrode of the machine for resistance welding of fusion strips, comprising a sponge connected to the busbar with a current-carrying insert and a rear clamping bar, with a current-carrying insert having a semicircular groove parallel to the side of the insert, the axis of which is located on the plane of the insert adjacent to the strip at the same time, a current-carrying element is installed in the groove with the excess of its plane above the insertion plane adjacent to the strip by at least 0.3 mm and the interaction guiding with the surface of the groove, while a current-carrying element of annealed copper wire is installed in the groove, the diameter of which is determined by

,

,

where D is the diameter of the semicircular groove, mm;

h is the excess of the plane of the current-carrying element over the surface of the insert, mm, and the axis of the groove is located at a distance from the side end of the current-carrying insert

L = 1 / 2D + e (mm),

where D is the diameter of the semicircular groove, mm;

e - the distance from the side of the electrode to the beginning of the semicircular groove is 2 ... 4 mm, allows you to:

- to improve the quality of the weld by ensuring uniform heating of the weld along the entire width of the strips during heat treatment;

- to simplify the design of the machine as a result of the lack of the need to install additional elements for the implementation of the process, in addition to placing a current-carrying element of a semicircular groove;

- effectively use such electrodes in welding machines installed in units for processing strips of high-carbon and alloy steels, the welded joints of which after welding and rapid cooling in air are hardened and become unsuitable for uninterrupted transportation and processing in the line.

Claims (3)

1. The electrode of the machine for resistance welding of fusion strips, comprising a sponge connected to the busbar with a current-carrying insert and a clamping plate, which is front relative to the welding axis, characterized in that the current-carrying insert is made with a semicircular groove parallel to the side of the insert, the axis of which is located adjacent to the strip of the insertion plane to be welded, and a current-conducting element interacting with it having a flat surface located in excess of avki not less than 0.3 mm. 2. The electrode according to claim 1, characterized in that the current-carrying element is obtained by placing in the semicircular groove a bar of annealed copper wire with its subsequent deformation to form a flat surface, the diameter d of which is determined by the dependence:

,
where D is the diameter of the semicircular groove, mm;
h is the excess of the surface of the current-carrying element over the surface of the current-carrying insert, mm 3. The electrode according to claim 1, characterized in that the distance from the side end of the current-carrying insert to the beginning of the semicircular groove is 2 ... 4 mm.

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