SU1166942A1 - Method of arc welding with non-consumable electrode - Google Patents

Abstract

The ARC WELDING METHOD by a non-melting electrode with heated filler wire, in which the filler wire and non-melting electrode are connected to one pole of the power source, characterized in that, in order to simplify the welding process of curved closed seams by eliminating the filler wire operation, the welding wire would eliminate the welding wire of the welding wire. the weld, heating the filler wire is carried out at the point of its departure, the resistance of which is greater than the arc resistance between the electrode and the product from 3 d about 20 times, and the filler wire is fed into the weld pool at a distance from the electrode of not less than c and not more than / 2-s, where c is the diameter of the welding wire, b is the width of the weld pool. O5 05 with

Description

The invention relates to arc welding with a non-consumable electrode and can be used in various sectors of the national economy in the manufacture of welded structures.

The purpose of the invention is to simplify the process of welding curved closed seams by eliminating the operation of turning the filler wire relative to the electrode and improving the quality of the seams.

FIG. 1 shows a scheme for implementing the welding method; in fig. 2 scheme of welding a curved joint, the plan.

The non-consumable electrode 1 (Fig. 1) and the filler wire 2 are connected to one pole of the power source 3. The power supply 4 serves to supply current to the filler wire 2, the electrode 1 is fixed to the holder 5. The wire 2 in the heating section is isolated from the holder 5 at using electroconductive tube 6. Electrode 1 and wire 2 are combined in one unit and are located inside nozzle 7, through which protective gas is supplied. Ammeters 8, 9 and 10 and voltmeter 11 are designed to measure the parameters of the welding mode. The arc is excited between the electrode 1 and the product 12 and the welding bath is introduced, after which the wire 2 is fed into the bath, which, when in contact with the bath, is heated by a Joule heat in the section, and the welding wire 2 does not unfold the relatively non-meltable electrode. At the site and the joint, the wire 2 is fed to the tail end of the weld pool 13, at site B to the head, and at sites S and H to the side of the weld pool.

As experiments have shown, if the section of heating the wire with 2 current is small, i.e. Rf,: ZrO-, or, 0, as a result of a sharp increase in the current, the filler wire 2 overheats, melts and breaks the bond with the weld pool. Since the current is Jp. on the filler wire 2 and the current on the arc U of the non-melting electrode 1 are connected to the common current of the power source J by the Kirchhoff law:

m 3 „, then an increase in the current J leads to a decrease in the current on the arc J. In connection with the ETLM, there are significant jumps on the arc of the non-melting electrode 1, which ultimately leads to an unsatisfactory formation of the weld groove.

With an increase in the length of the heating section L of the filler wire 2, its resistance increases. Here, the current on the wire Jp decreases inversely as Rn,

iv

L

Rn

current in the filler wire, A;

voltage drop on wire, V;

resistance of the heating wire filler current. Ohm yk voltage drop

Un corresponds to a fall

voltage on the arc. Oud then

U.

Jnrn

With a significant length h of the heating section of the filler wire 2, i.e. with Rp720-6 ("720), the efficiency of heating the wire with current decreases, since the power supplied in the wire as it passes through it j is equal to J decreases with decreasing 3" and increases Rn. At the same time, heat losses to the surrounding space increase, associated with an increase in the heating current ti jmacTKa, which also reduces the efficiency of wire heating.

Example. The weight of steel sheets of VNS-2 3.0 mm thick with an EP659 AVI filler wire with a diameter of 1.2 mm c / t from a power source VSVU-315, with a welding speed Uc 9 m / h, wire feed speed (J (7 35 m / h, with the total current of the power source J 165 A and the voltage across the arc} 10 V.

The welding process parameters are listed in the table.

As experiments have shown, the filler wire must be fed into the bath at a distance from the electrode not less than the size of its diameter and not closer to the boundary of the bath by the value of its diameter, i.e.

(B / 2-d} - “7x cj,

where t4 is the distance from the end of the non-consumable electrode to the filler wire,

MM f

fc is the width of the weld pool,

MMJ

cl - diameter of the filler wire, nts.

Moreover, with es (with the filler metal sticks to the end of the non-melting electrode, which leads to a breakdown of the welding process (see table, p. 7). With c (–d, the wire moves beyond the weld pool, does not melt completely, as a result A defect in the form of non-fusion is formed on the weld seam (see table, p. 11). Thus, by setting the length fi of the heating section on your filler wire 2 with current C corresponding to the resistance Rp of 3-20 RJ and arranging the filler wire 2 from the end non-melting gage electrode 1 on the corresponding Then, they start feeding the filler wire 2 into the weld pool. At the moment of contact with the end of the filler wire 2 of the weld pool, the total current of the power source 3 memory is increased by the amount of current on the wire Ld, measured by ammeters 8 and 10, respectively. By the end of the filler wire of the bath, the current on the arc D is reduced by the amount of current on the wire J, it is necessary to increase the current on the arc to the original value in order to ensure the desired penetration. Therefore, the total current 3 of the power source 3 is increased by the amount of current on the wire p

Since the arc resistance from

3 to 20 times less resistance of the filler wire, then an increase in the total current of the power supply source 3 leads to an increase in the main current

on the arc 3. The current on the wire D increases by no more than 3%, which does not affect the nature of its heating.

The invention allows to simplify the process of welding curved closed seams without turning the filler wire relative to the electrode, improve the quality of the seams and obtain an economic effect.

110 50 0.091

80

1 1.25

124 41 0.081

200

1.25

31.25 260 140 25 0.071 0.4 5.6

41.25 580 150 15 0.067 0.67 10

51.25 700 157 8 0.064 1.28 20

Overheating wire2, 2 lokki current. Melting it outside the weld pool. Bad seam formation, K 3,0

3.0

Good seam formation

Also

159

800

1.25

140 25

260

0.8

Table continuation

Inadequate

1.67 25.5

, 063 heating wire. Defects of a seam in the form of non-fusion, K 7 20

5.6

Sticking, 4

, 071 of the metal on the end of the non-melting electrode

a.d

Claims (1)

METHOD OF ARC WELDING OF A NON-MALABLE ELECTRODE with heating of the filler wire, in which the filler wire and non-consumable electrode are connected to one pole of the power source, characterized in that, in order to simplify the welding process of curved closed seams by eliminating the operation of turning the filler wire relative to the electrode and improving the quality of weld filler wire is heated at the site of its departure, the resistance of which is greater than the arc resistance between the electrode and the product from 3 to 20 ra And filler wire is fed into the weld pool at a distance from the electrode is not less than the magnitude d and a maximum value of L / 2-d, where d - diameter of the wire epileptic, t - sva'rochnoy bath width. <