RU2427456C1 - Method of contact flesh welding of round section articles and flesh trimming - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention may be used in welding round section articles at special-purposes welding machines mounted in drawing shops for integration of wire coils or for jointing reinforcing bars in construction. Ends of welded parts are fitted in electrodes of stationary and moving clamps provided with chilled steel semi-bushes with sharp edges arranged on opposed sides. Welding transformer is switched on to shift moving for fleshing off and precipitation. Fleshing off is conducted at increased welding voltage. After precipitation for preset allowance and transformer switching off, electrode clamping force is decreased at one of clamps till welded article slippage to cut off flesh heated in welding by aforesaid sharp edges of steel semi-bushes.

EFFECT: higher efficiency and precision of aligning faces.

3 cl, 3 dwg

Description

The invention relates to welding production, and in particular to methods and devices for flash butt welding by fusion of rods or rods, performed on specialized welding machines installed in drawing production for enlarging wire riots or in construction when connecting reinforcing bars.

Periodic welding of hot-rolled wire riots, specified in drawing units, not only ensures their continuous operation, but also allows to increase the weight of finished wire riots, while the duration of joining the riots should not allow the unit to stop or slow down. High productivity of welding machines under these conditions is achieved due to automation of the welding process and acceleration of auxiliary operations, in particular, the operation of removal of weld from welded joints, which is necessary before drawing them. The removal of burr is also necessary when welding reinforcing bars, since the reinforcement at the junction is a concentrator of alternating load in reinforced concrete products, which often causes destruction of concrete at the joints of the reinforcement. Currently, due to the lack of shredders on the welding machines, the shreds are manually cleaned with grinding wheels. In addition, when installing circular products for welding, due to the rapid wear of the electrodes made of copper alloys, difficulties arise in the axial alignment of the welded ends.

There is a method of removing grata on round products from heat-strengthened aluminum alloys D16T, D18 (see, for example, the book "Flash butt welding with resistance with the formation of the connection.” Sat scientific science. / Academy of Sciences of the Ukrainian SSR, edited by V. Lebedev - Kiev , EO Paton Electric Welding Institute, 1988, p.38 ... 39), in which the metal during extrusion is extruded into grath between the working ends of the electrode forming devices and, at the final stage of precipitation, is cut off by their edges and separated.

The disadvantage of using this method of removal of burr when welding steel products is the low resistance of the forming devices of the electrodes due to thermal softening of the edges when they come in contact with heated metal ends of the products.

There is also a method of removing the burr after welding the workpieces of a tap wrench with four semicircular knives with annular cutting edges covering the welded workpiece to the right and left of the burr in a separate filler (see the book "Flash butt welding with resistance with the formation of the connection.” Sat scientific. USSR Academy of Sciences under the editorship of V.K. Lebedev - Kiev, EO Paton Electric Welding Institute, 1988, p. 80 ... 82).

The disadvantage of this method of removing the burr is the inability to maintain the temperature of the weld heated during welding due to its rapid cooling when transferring the product to the burr, therefore, either reheating or using great effort to trim and separate the burr is necessary. In addition, when removing burr in this way on cooled products from hardened steels, cold cracks may appear at the junction.

The technical result of the invention is to increase productivity by combining welding operations and removing burrs after flash butt welding of circular products and improving the accuracy of combining the ends when installing the welded products for welding.

The technical result is achieved by the fact that in the method of removing grit after flash butt welding by fusion of circular products, including trimming and setting the ends of the products, clamping them in movable and fixed clamps with electrodes equipped with steel hardened half-sleeves having sharp edges facing each other, switching on the welding transformer and moving the movable clamp to reflow and draft, reflow is carried out at high welding voltage, after precipitation on a given allowance and about turning on the welding transformer, without removing the upsetting force, reduces the clamping force of the electrodes of the movable clamp before the welded products slip in them, while the fillet heated during welding is cut off by the edges of the steel half-sleeves of the electrodes of the movable clamp, and after wear of the edges of the steel half-sleeves of the electrodes of the movable clamp, after upsetting and disconnection of the welding transformer reduces the clamping force of the electrodes of the fixed clamp until the welded products slip in them, while the shear cut off during welding edges of half-plugs of electrodes of a fixed clip.

The inventive method of removing burr after flash butt welding by fusion of circular products, explain figure 1 ... 3, where:

- figure 1 schematically shows the position of the electrodes equipped with steel half-sleeves before welding with installed products;

- figure 2 schematically shows the position of the electrodes before stripping the edges of the edges of the half-sleeves of the movable clamp;

- figure 3 schematically shows the position of the electrodes before stripping the burr with the edges of the half-sleeves of the fixed clamp.

The inventive method of removing burr after flash butt welding by fusion of circular products is as follows:

- after trimming and feeding products 1 to the welding zone, they are clamped in the lower 2 and upper 3 electrodes of the stationary 4 and movable 5 clamps, while the steel hardened low-wear half-sleeves 6 reliably center the products 1;

- turn on the welding transformer (conditionally not shown in the figures) at an increased voltage to compensate for the voltage drop at the contact junctions between the lower 2 current-carrying electrodes and due to an increase in the installation length, and then the movable clamp 5 is moved during reflow and draft and weld items 1;

- after upsetting and turning off the welding transformer, without removing the upsetting force, reduce the clamping force of the electrodes 2 and 3 of the fixed clamp 4 until the welded products slip in them, while the edges 7 of the steel half-sleeves 6 of the electrodes 2 and 3 of the movable clamp 5 are brought closer to the heated during welding gratom 8 and cut it off;

- after wear of the edges 7 of the steel half-sleeves 6 of the electrodes 2 and 3 of the fixed clamp 4, steel half-sleeves 6 of the movable clamp 5 are put into operation.

For this:

- after upsetting and turning off the welding transformer, without removing the upsetting force, reduce the clamping force of the electrodes 2 and 3 of the movable clamp 5 until the welded products slip in them, while the fillet 8 heated during welding is cut off by the edges 7 of steel half-sleeves 6 of the electrodes 2 and 3 of the movable clamp four.

Thus, the proposed method for removing grit after flash butt welding by fusion of circular products through the use of electrodes of a welding machine equipped with steel hardened half-sleeves allows:

- significantly accelerate the process of removal of burr after welding with the edges of steel half-shells of the electrodes of the machine, which makes it possible to use it not only when welding reinforcing bars, but also in continuous drawing units under conditions of limiting the time allocated to docking riots before drawing;

- increase the accuracy of alignment when installing under welding ends of the products in the axial direction;

- to increase the reliability of the installation for welding the ends of circular products.

Claims (3)

1. The method of flash butt welding by fusion followed by removal of a round of round products, including trimming and installation of the ends of the products, their clamping by electrodes installed in movable and fixed clamps and equipped with steel hardened half-sleeves having sharp edges facing each other, turning on the welding transformer and moving the movable clamp to reflow and draft, while the reflow is carried out at high welding voltage, after settling on a given allowance and shutdown welding transformer, without removing the upsetting force, reduce the clamping force of the electrodes in the clamps until the welded products slip, and cut off the fillet heated during welding with the edges of the steel half-electrodes of the electrodes. 2. The method according to claim 1, in which the clamping force of the electrodes in the fixed clamp is reduced and the fillet heated during welding is cut off with the edges of the steel half-electrodes of the fixed clamp electrodes. 3. The method according to claim 1, in which the clamping force of the electrodes in the movable clamp is reduced and the fillet heated during welding is cut off with the edges of the half-plugs of the movable clamp electrodes.

Images