RU1838060C - Welding method - Google Patents

Description

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The invention relates to welding, in particular to welding methods in which a magnetic arc controlled welding arc is used in the heating source of the welded ends of the products and can be used mainly in the manufacture of welded structures, the welded ends of which are in the form of a straight line of them, curved, closed or non-cross-sections, when receiving butt joints, or when welding T-joints, in which the parts to be welded are located in two mutually perpendicular planes, with one end face minutes of (e.g., pipe, sheet, rod-th or non-closed profile piece ntura) adjacent to the side surface eugoy d (e.g., plates).

The goal is to expand the range of shapes and sizes of parts to be welded, to improve the quality of welded joints, to automate the control of the welding process.

In FIG. 1 shows the offset of the welding arc to the outer edges of the welded ends of the rods; in FIG. 2 - moving the welding arc along the outer edges, in the process of heating the welded ends of the rods; in Fig.3 - the offset of the welding arc in the region of the axial line of the welded rods; in FIG. 4 - rotational displacement of the welding arc to the outer edges before the draft of the welded parts; in FIG. 5 - offset welding arc on the outer edges of the welded pipe ends; in FIG. 6 - movement of the welding arc along the outer edges; in FIG. 7 - offset welding arc on the inner edges

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welded pipe ends; in FIG. 8-rotational displacement of the arc to the outer edges before the draft; in FIG. 9 - offset welding arc on the outer edges of the welded ends of the plates; in FIG. 10 - movement of the welding arc along the outer edges; in FIG. 11 - displacement of the welding arc to the inner part of the ends of the plates, linear movement of the arc along the axial line, in FIG. 12 - rotational displacement of the welding arc to the outer edges of the plates before the upset; in FIG. 13 - offset welding arc on the outer edges of the ends of the corners; in FIG. 14 - movement of the welding arc along the outer edges; in FIG. fifteen

- displacement of the welding arc to the inner part of the ends of the corners, angular displacement along the inner part; in Fig. 16 - rotational displacement of the welding arc to the outer edges of the welds before the draft; in FIG. 17a is a graph of voltage

. welding arc during welding; in FIG. 176 is a timing chart of a change in the magnitude of the axial Ba component; in FIG. 17c shows timing diagrams of the variation of the welding current value Ig (curve 1) and the displacement S (curve 2) of the movable plate of the welding machine.

1,2- welded parts; 3 - welding arc; 4, 5 - magnets.

A method of welding end-to-end parts (e.g., rods) end-to-end is as follows.

Rods 1 and 2 (Fig. 1) to be welded are installed with a certain arc gap of 1.5-2 mm, which is typical for almost all types and sizes of parts to be welded. Magnets 4 and 5 are placed coaxially with the welded rods. The magnets are mounted in such a way that they create, on the initial

stage asymmetric flows directed towards each other. In the arc gap, a control magnetic field B is formed, consisting of a radial Bp component and an axial Ba component. ;

Then the rods are reduced to the contact of their ends, they include a power source for the welding arc. (Welding rectifier having a falling external characteristic connected by one pole to the part, which is the anode, and the second pole to the part, which is the cathode). After that, the rods are bred into a fixed arc gap. Thus, by short circuiting the welding arc 3 is excited.

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The established value of the magnetic induction shifts the welding arc to the outer edges (Fig. 1). The process of heating the welded ends occurs when the welding arc moves along the outer edges (Fig. 2), in the zone with an increased value of Bp, which ensures arc movement that is stable with high speed. When the welding arc moves along the outer edges, its position is controlled by the magnitude of the voltage. If the voltage rises above the rated voltage, the magnitude of the magnetic induction of the programmed magnetic control field decreases. Otherwise, the welding arc breaks. When the voltage decreases below the nominal, the welding arc shifts to the inside of the welded ends, and the magnitude of the magnetic induction of the programmed magnetic control field increases. Otherwise, the process is unstable, with short circuits.

Due to the linear expansion of the welded ends, the voltage changes in a predetermined range. When the nominal voltage value is reached, which is necessary for the plastic deformation, heating of the ends, the magnitude of the magnetic induction of the programmed magnetic control field is changed. The welding arc is shifted to the centerline region of the welded rods (Fig. 3). There is a change in the magnitude of the welding voltage. When the voltage corresponds to a certain range of values, the magnitude of the magnetic induction of the magnetic induction and the welding current change. Changing the magnitude of the magnetic induction leads to a rotational displacement of the welding arc to the outer edges of the welded ends (Fig. 4). A simultaneous increase in current leads to the purification of the entire surface of the welded ends from oxides. Upon reaching a certain voltage value on the arc, the rods are sedimented.

The method allows welding of closed loop parts (e.g. pipes). In this case, the method is as follows.

Pipes 2 and 1 (Fig. 5) to be welded are installed with a certain arc gap. Permanent magnets 4 and 5 are placed coaxially with the pipes to be welded. The magnets are mounted in such a way that they create, at the initial stage, asymmetric flows directed towards

each other. In the arc, you form a magnetic field B.

Then the pipes are brought into contact with the HV of their ends, including a power source. After this, the pipes are bred into a certain arc gap, arc 3 is excited. The set value of the magnetic duction biases the arc to the outer edges Ki / (Fig. 5). The process of heating the ends occurs when the welding arc is moved along the rim edges (Fig. 6). Moreover, its position is controlled by the magnitude of the voltage.

Due to the linear expansion of the welded ends, the voltage changes in a certain range. Upon reduction of the nominal value of voltage - eni corresponding to the necessary plastic deformation, heating

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Tsrtsov, there is a change in the magnitude of the m} magnetic induction of the software controlling the magnetic field. The welding arc is shifted to the inner edges of the ends Tf ub (Fig. 7). There is a change in the value

i welding voltage When the voltage corresponds to a certain range of values, the magnitude of the magnetic induction changes and the welding current increases. A change in the magnitude of magnetic production leads to a rotational displacement of the welding arc to the outer edges of the ends of the pipes (Fig. 8). A simultaneous increase in the welding current leads to the purification of the entire surface of the ends from oxides. Upon reaching a certain value of the arc pressure, pipe upset is produced. The method allows butt welding of ptastins. In this case, the essence

Yusoba is as follows.

Plates 1 and 2 (Fig. 9) to be

zarak, set with a specific arc gap. The magnets 4 are placed coaxially with the plates to be welded and the magnets are mounted in this way

о they create, at the initial stage, asymmetric flows directed towards each other. A control magnetic field forms in the arc gap

. Then the plates are brought into contact with their ends, they include a power source for the welding arc. After this, the plates on a certain arc gap | approx. By means of a short circuit, the welding arc 3 is excited.

The set value of the magnetic in-:: position shifts the welding arc to the outer edges (Fig. 9). The process of heating the ends occurs when moving the pile

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a rock arc on the outer edges (Fig. 10). The position of the arc is controlled by the magnitude of the voltage.

Due to the linear expansion of the welded ends of the plates, a change in voltage occurs in a certain range. Upon reaching the nominal value of the arc voltage corresponding to the heating of the ends necessary for plastic deformation, the magnitude of the magnetic induction of the programmed magnetic control field changes. The arc is shifted to the inside of the welded ends of the plates (Fig. 11), where it begins to linearly move. There is a change in the magnitude of the welding voltage. When it corresponds to a certain range of values, there is a change in the magnitude of the magnetic induction and an increase in current. Changing the magnitude of the magnetic induction leads to a rotational displacement of the arc to the outer edges of the ends of the plates (Fig. 12). A simultaneous increase in current leads to the cleaning of the entire surface of the ends from oxides. Upon reaching a certain arc voltage, the plates are deposited.

The corners are welded in a similar manner (Figs. 13-16), with the only difference being that the arc makes a movement corresponding to the cross section of the corner profile.

Example. Welded rods with a diameter of 25 mm from Steel 45 are installed in the clamps of the machine, with a gap of 1.3 mm and secured by the power devices of the machine. Then, using a short circuit, an arc is excited at a current of 200 A. When it is excited on the axial line of the ends to be welded, the voltage value varies from 15 to 20 V, depending on the position of the welding arc. The initial value of the magnetic induction of the programmed magnetic field (Bp 75 ml, Ва 400tТ) is established, shifts the arc to the edges until the set voltage value is set within 22 29 V. After that, during heating of the ends, at current arc 120 A, the voltage is maintained within the specified limits. With increasing voltage on the arc, in the initial stage of the process 0 ... 3 s. Above the set value, the arc breaks. To prevent this from happening, the magnitude of the magnetic induction decreases by 1.3 ... 2 times, to the value of returning the arc to the voltage limits specified. With a decrease in the voltage across the arc, in the initial

process steps 0 ... 3 s, a short circuit occurs below the set value. To prevent this from happening, an increase is made of the value by 1.3 ... 2 times, to the value of returning the arc to the voltage limits.

Due to the linear expansion of the ends to be welded, when they are heated, a predetermined voltage value on the welding arc decreases by 1.05.,. 1.4 times, respectively, from Uzad. These stress values correspond to the heating of the ends necessary for plastic deformation; a decrease in the magnitude of magnetic induction by 10 ... 20 times occurs. The arc is shifted to the region of the axial line of the welded ends of the rods within 0.01 ... 0.1 s. After the voltage value is reached 1.5 times lower than the Uzad-magnetic induction is increased by 2. 2 times the initial value and the current is increased 5 ... 7 times. The increase in magnetic induction leads to rotational displacement of the arc to the outer edges of the ends. A simultaneous increase in current leads to the purification of the entire surface of the ends from oxides. Upon reaching the voltage across the arc, respectively, 1.4 ... 1.05 times greater from Uzad .. the rods are upset. The result is a welded joint. The magnitude of the shortening of the rods after welding is 7 mm. Compression is carried out at a speed of at least 150 mm / s with a force of 70,000 N. The total welding time was 11 seconds. Welding a batch of rods with a diameter of 25 mm using this method showed that when setting the arc gap between the ends of the parts to be welded with a sufficient accuracy of 1.3 ± 0.1 mm, the quality of the joints is high and is at the level of the base metal according to the main indicators. Joint tests were carried out on

existing rules and regulations.

The quality of the joints has improved due to a more accurate welding process, individually for each joint.

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As a result of applying the proposed welding method, a uniform, without undercutting, formation of a seam around the entire perimeter of the joint was obtained.

Metallographic analysis in the fusion zone revealed no fusion and nonmetallic inclusions.

Feasibility from the implementation of the proposed method lies in the fact that it is possible to weld pipes, sheet, rod or profile parts of an open loop.

In addition, the proposed method simplifies the control system and welding equipment. There is no need to use an additional magnetic field control device and a pulsed current source worth 1000 rubles.

When welding a pipe with a diameter of 42x8 mm and a plate with a thickness of 4 mm by the proposed method, there is no need to use a ferromagnetic core, which reduces the welding time of 1 joint by 3 s.

Claims (1)

The claims A method of welding with heating by an arc and subsequent upsetting, in which a control magnetic field is created in the gap of the joint being welded with a constant in the direction of the radial component of the magnetic induction, moving the arc along the surface of the joined ends, characterized in that, in order to expand the range of shapes and dimensions of the parts to be welded, improvement of the quality of welded joints, automation of welding process control, the arc is moved towards the outer edge of the parts to be welded, changing the magnitude of the magnetic induction, and the moment of change in the magnitude of the magnetic induction is determined upon reaching a predetermined voltage value on the arc. 1838060 Figure 3 4 Fie. 5 Figure 1 FIG. 5 FIG. 7 FIG. 9 Vut. 10 fui.11 FIG. 12Ja3i / 3 FIG. ft 7ui 16 i S mm editor Compiled by I. Pentegov Tehred M. Morgenthal t, c S. t.f Jh 1 P 8. FIG. / 7 t.c Proofreader A. Motyl