SU916169A1 - Arc welding method - Google Patents

Description

The invention relates to the season. production, namely, to methods of arc welding with the elimination of the magnetic blast.

(There is a method of arc welding, wherein the front arc of a ⁵ sensor for measuring the magnetic field intensity at the weld and Gurr nalom, removable from the sensor, controls the current of the electromagnet, creates a controlling magnetic field. A method implemented in a device for magnetic control of the situation in the arc zone [ one].

However, this method does not ensure the quality of welded joints when welding in a groove or along a gap. This is due to the fact that the sensor located between the welded parts in the welding process further affects a magnetic field HA _m conducting welding current along the cutting or the slit, which causes significant, and the welding po_scheli unacceptable error at kompensa2

of the disturbing arc of the magnetic field. As a result, the electromagnet creates a control field with insufficient or excessive intensity to fully compensate for the disturbing arc of the magnetic field.

The closest to the present invention is an arc welding method in which a control magnetic field is created in a weld butt joint, and the magnetic field intensity is controlled by two signals taken from sensors located during welding in a butt joint on both sides of the arc. Both sensors measure the intensity of the magnetic field at the welding site E2). .

The disadvantage of this method is the limited area of its primeneniya. This is due to the fact that in some cases, depending on the shape of the groove and the way it is filled, the sensor is installed at the same distance behind the arc and at the same level as

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sensor installed in front of the arc, it becomes very difficult because of the presence of the bead of weld metal behind the arc. And in vertical arc welding in protective gages using slotted grooves, this method is completely unacceptable, since the space behind the arc is filled with molten metal, and a welding head is followed by a slide that prevents the molten metal from flowing out, which prevents the sensor from being installed behind the arc .

The purpose of the invention is to improve the quality of welds with narrow deep grooves with vertical movement of the welding electrode during the welding process.

This goal is achieved by the fact that in the method of arc welding, in which a control magnetic field is created in the weld butt weld, the magnetic field intensity is controlled by two summable signals, one of which is removed from the sensor to measure the magnetic field at the welding site. use the voltage removed from the circuit of the welding arc and is proportional to the magnitude of the welding current ka. <

FIG. 1 shows the distribution of the magnetic field induced by the welding current, along the gap or slot of the joint; in fig. 2 - ₃₅ cheniya exception principle component of the magnetic field caused by the welding current and the compensation error in the caller; in fig. 3 "block diagram of a device implementing the proposed method.

The X axis (FIG. 1) shows the distance along the gap of the joint to be welded, mm; Y axis - the value of magnetic induction, T; Point A is the installation location of the sensor; Point B is the location ^{45 of the} welding electrode; B ^ and Wei ₂ are the magnetic fields induced by the welding currents 1 ^ and 1 _{sec d} , with> ^. *

The nature of the distribution of the power lines of this field depends on the direction of the current flowing through 5 ° C. The magnitude of its intensity depends on the magnitude of the welding current, the magnetic properties of the material of the parts to be welded (magnetic permeability, induction of saturation, etc.), "5

thickness of the parts to be welded, geometrical parameters of the welding gap, coordinates of the measurement point on the X axis.

At the same time, it is known that in the process of welding parts their magnetic properties, thickness, and geometrical parameters of the gap of the joint to be welded remain unchanged. The coordinate of the measurement point does not depend on the physical properties and we are entitled to accept it as a constant. In this case, the expression for the magnitude of the magnetic field in the welding gap induced by the arc current takes the form

B = ^ 1 ^,

where K4 = K X _l is the proportionality coefficient, in which the K coefficient expresses the constancy of the magnetic properties and the geometric dimensions of the parts to be welded, and X _{4 is the} coordinate of the point, the change of rhenium. '

From this it follows that the magnitude of the magnetic induction at any measurement point during the welding process is directly proportional to the magnitude of the welding current. Or, in other words, the magnitude of the welding current characterizes the magnitude of the magnetic field in the gap of the welded joint induced by it.

The X axis (Fig. 2) shows the distance along the joint, mm; on the Y axis, the value of magnetic induction, T; Point A is the sensor installation site; point B is the place of the welding electrode ;, point B is the point where the distance from the electrode is equal to the distance between the electrode and the sensor; In _o - the field deflecting the welding arc; В ^ й - field induced by the welding current.

The electrical signal Sd, coming from the sensor at point A, is proportional to the sum of the magnitudes of the intensities of the magnetic fields Bo <and ’We ^ at that point. The electrical signal Sd, coming from the welding current circuit, is set proportional to the intensity of the magnetic field of the HF induced by the welding current, at point B. Produc-,. For the addition of these signals, which is easily achieved by known circuit solutions, we obtain

Xia + = Β (χ + Weich ^- V _m .

Thus, using a sensor and a signal taken from the welding current circuit, we obtain a signal characterizing the intensity of the deflecting magnetic field around the arc, and the errors due to the effect on

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The sensor of the magnetic field induced by the welding current is completely excluded. In this case, changes in the welding current during the welding process lead to an automatic proportional change in both the induced magnetic field acting on the sensor and the signal from the welding current circuit.

Method · arc welding with the elimination of the magnetic blast is carried out 10. as follows.

On the welded parts 1 and 2 (FIG. 3) of structures from high-strength steels with a thickness of up to 100 mm, a welding machine “Rhythm” is installed. Above the welding 15 head 3 of the automaton with the help of a bracket is fixed at a distance of 10-20 mm the Hall sensor 4 of type X-211, which serves to measure the intensity

(magnetic field. Below the welding head set electromagnet 5.

When welding parts of greater thickness, an electromagnet is usually used. de solenoid wound on the welded parts. In the same place, below svarochno- 25

th head mounted slider _6; which, together with the lining 7, serves to prevent the molten metal from leaking 8. The electromagnet 5 and the slider 6 are fixed on the tractor (not shown) of the welding machine and move together with the welding head 3. The head 3 is connected by cable with a welding source 9 of VDu type ~ 504 . In the circuit between the head 3 and the source 9, a shunt 10 of the type 75 IMS is installed at 75 mV. The welding process is started by supplying a protective gas (CO ^) to the welding zone and water to the cooling system of the welding head, slider, lining and sensor. Turn on the hardware block 11 of the device to eliminate magnetic blast.

At the same time acting on the sensor 4 ·

The deflecting magnetic field causes a voltage to appear at its pins, which is fed to the input of a highly sensitive amplifier like UPD1-03, where it is amplified, and then goes to control the current of the electromagnet ₅₀ kits 5. The ammeter in the circuit of the electromagnet shows the value of the current at which it creates magnetic field, compensating the effect of the deflecting field. Include automatic welding machine. & At the time of ignition of the arc, an additional magnetic field arises in the gap, due to the welding current, which affects the sensor 4. Its magnitude at a distance of 20 mm from the electrode is of the order of 0.01 T. This leads to a change in voltage at the terminals of the sensor 4 on 20-30 mkv. Simultaneously with the ignition of the arc from the shunt 10, a voltage proportional to the magnitude of the welding current begins to flow into the hardware unit 11. The potentiometer in the voltage divider circuit establishes the proportionality of this voltage to the value of the additional magnetic field acting on sensor 4.

In this case, the ammeter should show the same current value of the electromagnet as it was before turning on the welding current. As a result, a voltage of 20-30 μV is additionally applied to the input of the highly sensitive amplifier, which compensates for the change in voltage at the outputs of sensor 4, caused by the magnetic field induced by the welding current on it. Thus, only a voltage proportional to the magnitude of the magnetic field deflecting the welding arc and the current in the electromagnet 5 is fed to the amplifier input, as it moves along the junction of the welding head 3, sensor 4 and electromagnet 5, it is constantly supported + enough to compensate for it fields. This is how the welding process is carried out with the elimination of the magnetic blast.

The proposed method in comparison with the base object, which is a known method, provides for the expansion of the scope of welding with the elimination of magnetic blast on almost all types of welded structures with X- and Y-shaped groove edges, when welding joints with slotted grooves in the welded housing ”! and t ₍ d.

Claims (1)

Claim The method of arc welding, in which ^: in the cutting of the welded joint, a control magnetic field is created, and the intensity of the magnetic field is controlled by two summable signals, one of which is removed from the sensor to measure the intensity of the magnetic field at the welding site, characterized in that seams with narrow 7 916169 8 deep cuttings in the vertical movement of the welding electrode 'and the welding process, as the second signal, use the voltage removed from the welding arc circuit and is proportional to the welding current.