SU664785A1 - Arrangement for forming joints at resistance welding - Google Patents

Description

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The invention relates to welding and can be used in contact butt, spot or roller welding, when it is necessary to limit or almost completely eliminate the extrusion of the heated sections of the parts being welded.

A device is known with which an additional compressive force 1 is applied in the process of resistance spot welding to the side surfaces of a flat-flattened pipe section.

This device is a rigid bracket, at the ends of which two guides are fixed along one axis. In the guides are placed the i-slide, at the ends of which, facing the inside of the bracket, are fixed in the form of metal plates through electrical insulating gaskets. Through these stops, an additional compressive force is applied to the side surfaces of the flat-flattened section of the pipe, thereby limiting the extrusion of the metal of these sections during the welding process.

A disadvantage of the known device is that the contact of the product to be welded with its stop plates results in shunting of the welding current (through these stop plates). This is most pronounced in metal welding.

with low yield strength at elevated temperatures, such as zirconium and its alloys. Due to the shunting, the side surfaces of the product are heated excessively, the heated metal is squeezed into the gaps, sticks to the stops, splashes and burning are created.

Also known are devices in the form of forming metal rings, which are used for limiting the flow of a metal during butt contact welding 2.

Their disadvantage is the same - contact with them of welded parts leads to shunting of the welding current.

The closest to the technical essence of the present invention is a device for forming a joint in resistance welding, comprising separable shoes Z.

These shoes are made of electrically insulating material and cover the parts to be welded in the area of their departure.

A disadvantage of this device is the poor thermal conductivity of the material from which these shoes are made, which leads to a deterioration in the quality of the seam.

The aim of the invention is to improve the quality of the welded joint by removing heat from the weld zone.

This goal is achieved by the fact that

detachable shoes are made in the form of packages, fastened together by a plane-parallel metal plates electrically isolated from each other, the planes of which are perpendicular to the plane of the connector of the shoes. The split shoes are also made of transformer steel packages, the surfaces of which are covered with a layer of high-temperature insulation.

FIG. 1 and 2 shows the proposed device. The device consists of a ring cage 1, clips 2 and sectors of detachable shoes 3.

The device works as follows.

The welded pipe is clamped with current-carrying jaws of the fixed current-clamp with some time. The proposed device is installed on the protrusion of the current lead-clamp part of the welded pipe. Through a rigid ring cage 1 and clamps 2 sectors of the detachable shoes 3 are supplied to the pipe at the site of its departure. The plug is installed in the movable electrode. After application of the compression force to the parts to be welded, a pulse of welding current is passed through them.

The proposed device, during the welding process, limits the extrusion of the heated metal of the parts to be welded to the outside and directs the flow of burr inside the pipe. In this case, the implementation in the form of packages, fastened together, metal plates insulated from each other, the sectors of the metal ring stop ensure heat removal from the weld zone and eliminate shunting of the welding current, thereby ensuring a high-quality weld.

In order to simplify manufacturing, the sectors of the split ring stop can be made of packages glued together between plates of transformer steel with a thickness of 0.2-2 mm, the surfaces of which have a layer of high-temperature insulation.

This design of the detachable shoe of the device allows the heat sink intensity to be varied over a wide range.

varying the thickness and material of its component plates.

The main field of application of the invention is sealing by butt contact welding with the help of end parts of shells of heat-generating elements of power reactors.

 In this case, the shells can be made of various alloys, for example, zirconium or heat-resistant steels, including dispersion-hardened ones.

The use of the proposed device allowed us to ensure high quality of welded joints and welding stability.

The use of the proposed device in sealing joints with butt welding will make it possible to obtain joints without external flash and high quality welding.

eliminate the time-consuming operation of cutting the latter.

Claims (3)

1. An apparatus for forming a joint in contact welding, comprising detachable shoes, characterized in that, in order to improve the quality of the welded joint by ensuring heat removal from the welding zone, detachable shoes are made in the form of packages of plane-parallel, electrically insulated from each other metal plates whose planes are perpendicular to the plane of the connector of the shoes. 2. A device according to claim 1, characterized in that the detachable shoes are made of packages of plates glued together. transformer steel, whose surfaces are covered with a layer of high-temperature insulation. Sources of information taken into account in the examination 1. USSR author's certificate No. 485841, cl. In 23K P / S, 1973. 2. USSR author's certificate number 220373, cl. In 23K 11/02, 1966. 3.Orlov B.D. Technologists and equipment for resistance welding. Engineering, M., 1975, p. 108