RU2377105C2 - Burner for shielded arc welding - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to burner for shielded arc welding and can be used in welding in narrow cutting with ratio of depth to width 20:1 and more of products, containing thick-walled welding structures, in heavy and normal mechanical engineering, ship-building and military-industrial establishment. Burner contains casing with fixed in it cylindrical or confuser nozzle, nonconsumable electrode or contact tube of consumable electrode. Between casing and nozzle it is located packet consisting of two grids with cell from 0.04 up to 0.25 mm, daylight area ratio not more than 0.3 and distance between grids equal to 20 dimensions of cell. In clearance between packet of grids and nonconsumable electrode or contact tube of consumable electrode it is located bushing implemented from the side of casing in the form of sleeve with installed in it formation of grooves by alternating relative to each other flat rings with section in the form of rectangle, diametres of which are equal at the outside and different from the inside.

EFFECT: there is increased length of protective jet in deep narrow cuttings and it is provided welding of maximal thickness.

4 cl, 4 dwg

Description

The burner belongs to the means of technological equipment that provides arc welding in shielding gases in a narrow groove with a ratio of depth to width of 20: 1 or more, and can be used in industries where products containing plate-welded structures are manufactured - mechanical engineering, heavy, medium, transport, shipbuilding, military-industrial complex, etc.

At the moment, arc welding in shielding gases for deep narrow cuts is performed in two ways. According to the first method, a non-consumable tungsten electrode or a water-cooled mouthpiece is introduced into a narrow groove, through which a wire is melted to the arc. A burner nozzle is located above a narrow groove, from which a jet of protective gas flows into the groove, which provides gas protection. The advantage of this method is the reliability of such burners and a long resource of their operation time. The disadvantage is the depth of the narrow grooves at which gas protection is provided, i.e. welding is possible, is limited to 80-100 mm.

According to the second method, the water-cooled mouthpiece introduced into the groove terminates in a nozzle through which a protective gas is supplied to protect the welding zone. The advantage of these burners is the unlimited cutting depth at which welding is possible. The disadvantage of this method is the unreliability of the burners during operation and an insignificant resource of working time. Almost all literary sources point to this fact. This is what limits the application of this welding method.

A known torch is taken into account (USSR author's certificate No. 614914, M. class. ² V23K 9/16), which is located above the edges of a narrow narrow groove during the arc welding process, and the protective jet flowing out of it ensures protection of the weld pool and the cooling part a seam at the bottom of cutting. It contains a casing with a confuser nozzle fixed on it, a non-consumable electrode fixed in the casing, and a packet of finely meshed opaque light grids installed between the casing and the nozzle. The passage of the non-consumable electrode from the housing to the nozzle is through a sleeve hermetically mounted on the grids in the center of the package. To degenerate the turbulence that forms at the angle of the combination of horizontal and vertical cutting edges in the nozzle, two parallel plates are mounted, located on opposite sides of the axis of the burner and extending beyond the lower cut of the nozzle, while the length of the plates is greater than the diameter of the nozzle.

The disadvantage of analogues: the limited length of the protective jet in narrow deep cuts, as a result of which the limited possibilities of welding cuts with a depth of up to 80-100 mm.

Known burner (SU 1669658 A1, B23K 9/16, 08/15/1991), adopted as a prototype, including a burner body, a nozzle cylindrical or konfusornoe, a mouthpiece for supplying a melting electrode into the arc and located between the body and the nozzle packet of grids, consisting of two grids . This torch, in combination with the arc welding method using a crevice gap (USSR author's certificate No. 4777798, class C. B23K 9/16), it is possible to weld in protective gases by deep narrow grooves to a depth of 100 mm, which is confirmed by the data of [1 ]. The disadvantage of the prototype: a small length of the protective stream in a narrow deep cutting.

The technical result is to eliminate the specified disadvantage of the prototype, i.e. an increase in the length of protective jets when welding along deep narrow grooves with the same dimensions of the torches themselves, located above the edges of the grooves. The technical result is achieved by the fact that the sleeve, designed to pass through a packet of grids of a non-consumable electrode or a mouthpiece of a consumable electrode, is made from the side of the housing in the form of a cup, which is part of the sleeve, into which alternating flat rings having a cross section in the shape of a rectangle, the diameters of which same on the outside and different on the inside. Such devices are called labyrinth seals and are widely used in turbine engineering to dampen the rate of gas leakage from the turbine housing.

The proposed burner, containing a package of grids installed in the inlet section of the nozzle with a sleeve made in the form of a glass into which the sealing substances are installed, is illustrated by drawings, in which Fig. 1 shows a longitudinal section of a General view of the burner, in figures 2, 3, 4 are different types sealing the gap between the electrode or the mouthpiece and the sleeve glass.

The claimed torch for arc welding in a protective gas environment contains: 1 - housing; 2 - nozzle; 3 - non-consumable electrode; 4 - a packet of grids; 5 - a sleeve with a glass 8 for passing through a packet of grids of a non-consumable electrode or mouthpiece; 6 - the gap between the sleeve and the electrode; 7 - mesh; 8 - a glass to the sleeve 5; 9 - rings of different inner diameter and thickness; 10 - soft polyamides or polyimides; 11 - fraction or shavings.

The physical nature of the issue is that the diameter of the bore of the sleeve is always 0.2-0.4 mm larger than the diameter of the non-consumable electrode or the mouthpiece of the consumable electrode included in it. This gap is necessary both for the vertical movement of the non-consumable electrode or the mouthpiece of the consumable electrode during filling of the groove, and for the possibility of thermal expansion of the electrode without sticking to the walls of the sleeve or the possibility of removing the mouthpiece during periodic cleaning or replacement (see figure 1 node A). Due to the difference in aerodynamic drags, the gas velocity through the gap between the sleeve and the mouthpiece is significantly higher than the gas velocity through the grid packet. Therefore, in the vicinity of the electrode after the sleeve, a significant velocity difference is formed on the nozzle side, leading to the formation of a disturbance region. This region, moving downstream along with the core of the protective jet, gradually increases in transverse dimensions and at a distance of ≈1.5 D (D is the nozzle exit diameter of the nozzle) of the axis of its exit, this disturbance is mixed with the boundary layer of the jet edge, due to which starting from this distance, the entire core of the jet contains air located in the gas of the boundary layer of the jet edge. This leads to a violation of gas protection. When a non-consumable electrode is heated, this phenomenon ceases to affect the result of the experiment, since the resistance in the gap will increase sharply. However, under isothermal conditions, a similar phenomenon was noted for a long time, and therefore, the gap between the sleeve and the electrode when studying gas protection in conditions of increased overhangs of the electrode was always sealed with metal foil (from sweets and cigarettes).

In the initial stage of gas protection studies in deep narrow cuts, this effect was not taken into account, and therefore underestimated results appeared in the development of [1].

When repeating these experiments, the gap in the sleeve was now sealed and the results increased by 2 times or more.

In the conditions of industrial operation of the burners, sealing the gap between the sleeve and the non-consumable electrode or the mouthpiece of the consumable electrode can be performed by the following methods:

1. In the presence of electrodes warming up to high temperatures, it is necessary to use a labyrinth seal with the following parameters: the minimum number of grooves is 7; the maximum ratio of the width of the groove to its depth corresponds to 1: 4; the maximum gap between the surface of the inner diameter of the ring or the sleeve and the surface of the electrode or mouthpiece is 0.15 mm (data on studies of the parameters of labyrinth seals are given in [2], see figure 2).

2. In the presence of a water-cooled mouthpiece, a polyimide or polyamide in the form of cotton wool, fiber, with a temperature of the onset of decay from 300 ° C or more is packed in a glass of the sleeve (see figure 3).

3. If there is an uncooled mouthpiece, the glass on the sleeve can be filled with stainless shot or shavings whose granule sizes are larger than the gap between the walls of the sleeve and the electrode or mouthpiece (see figure 4).

List of used works

1. Fedorenko G.A., Burashenko I.A., Ardentov V.V., Grishchenko L.V. On the laws of gas protection without cutting edges with a gap gap. “Welding production”, No. 5, Articles 10-12, 1978.

2. Fedorenko G.A., Ardentov V.V., Kudoyarov B.V. Features of the work of devices providing local gas protection during welding. “Automatic welding”, No. 4, Art. 64-67, 1980.

Claims (4)

1. A torch for arc welding in a medium of shielding gases of large thicknesses with narrow deep grooves, comprising a housing with a cylindrical or confuser nozzle fixed in it, a non-consumable electrode or a mouthpiece of a consumable electrode, a package consisting of two grids with a mesh of 0 from between the housing and the nozzle , 04 to 0.25 mm, with a live section coefficient of not more than 0.3 and a distance between grids equal to 20 mesh sizes, and a sleeve in the gap between the grid packet and a non-consumable electrode or a mouthpiece of a consumable electrode made from the sides a sleeve-shaped housing defined therein to form the grooves alternate between a flat ring with a rectangular cross section, which are identical outside diameters and different inside. 2. The burner according to claim 1, characterized in that the minimum number of grooves between rings of different sizes corresponds to seven, the maximum ratio of the width of each groove to its depth corresponds to 1: 4, the maximum clearance between the surface of the inner diameter of the ring and the surface of the electrode, or mouthpiece, or bushings and the surface of the electrode or mouthpiece is 0.15 mm. 3. A torch for arc welding in a medium of shielding gases of large thicknesses with narrow deep grooves, comprising a housing with a cylindrical or confuser nozzle fixed in it, a non-consumable electrode or a mouthpiece of a consumable electrode located between the housing and the nozzle, a package consisting of two grids with a mesh of 0 , 04 to 0.25 mm, with a live section coefficient of not more than 0.3 and a distance between grids equal to 20 mesh sizes, and a sleeve in the gap between the grid packet and a non-consumable electrode or a mouthpiece of a consumable electrode made from the sides a sleeve-shaped casing which is filled with polyimide or polyamide in the form of wadding, or fabrics, or fibers with onset temperature of the decay of 300 ° C and above. 4. A torch for arc welding in a medium of shielding gases of large thicknesses with narrow deep grooves, comprising a body with a cylindrical or confuser nozzle fixed in it, a non-consumable electrode or a mouthpiece of a melting electrode, a package consisting of two grids with a mesh of 0 from between the body and the nozzle , 04 to 0.25 mm, with a live section coefficient of not more than 0.3 and a distance between grids equal to 20 mesh sizes, and a sleeve in the gap between the grid packet and a non-consumable electrode or a mouthpiece of a consumable electrode made from the sides a sleeve-shaped casing which is filled with grit or stainless chips that are larger than the size of the gap between the sleeve and the electrode or mouthpiece.

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