SU1386400A1 - Arc welding method - Google Patents

Abstract

The invention relates to gas-shielded arc welding and can be used in various areas of welding machines for welding hard-to-weld steels and alloys with melting and weld electrodes. The goal is to improve the quality of welded joints when welding in a pulsed mode with a pilot arc by preheating the edges being welded. The method consists in the fact that after the arc 3 is deflected by an angle to the preset value, its active spot 8 is stabilized in this place while reducing the intensity of the magnetic field and moving the electrode 1 or the product 2 at a welding speed. As a result, the active arc spot remains stationary for the specified time on the edges to be welded. This allows them to be preheated, and at the moment when the magnetic field strength becomes zero and the electrode is above the place where the active spot of the arc was stabilized, a welding current pulse is activated. Stabilizing the position of the active spot of an arc deflected by a transverse magnetic field with an angle of forward during the welding process allows preheating of the edges to be welded directly with a welding arc without the use of additional heat sources. 2 Il. S (L 00 00 (35 o

Description

The invention relates to gas-shielded arc welding and can be used in various areas of mechanical engineering for welding hard-to-weld steels and slabs of meltable and non-consumable electrodes,

The aim of the invention is to improve the quality of welded joints when welding in a pulsed mode with an on-duty arc by preheating the edges being welded.

FIG. 1 is a block diagram of a device that implements a method of welding by a magnetically controlled arc; Fig. 2 shows a cyclogram of the change in the external magnetic field, the movement of the end of the electrode and the active spot of the arc, the change in the amperage of the welding and standby arcs.

The welding method is carried out as follows.

Between the electrode 1 and the welded product 2 excite the arc on duty

3c magnitude, current 1, Immediately after initiating the arc, the relay is activated

4 arcs, including simultaneously an external magnetic field generator 5 and a torch moving mechanism 6. The generator 5. connected to an electromagnet 7 creating a transverse magnetic field in the arc burning zone, is made so that after it is turned on, the magnetic field immediately increases to a predetermined value. Simultaneously with the increase in the intensity H of the external magnetic field in section A-B (Fig. 2), during the time tO, I s, the active spot of the duty arc 8 will move at a speed V to mm forward relative to the axis of the electrode. The electrode during this time will move to s

In the area B – B v O (FIG. 2), the active spot of the arc 8 remains stationary (stabilized at the heating point) due to the simultaneous decrease in the intensity of the external magnetic field and the displacement of the electrode at a constant welding speed, which allows preliminary

O heated edges to be welded.

B the moment when the magnetic field strength is zero, (bit C – G to f. 2), the signal from the generator 5 is fed to the pulse shaping unit 9 included in the control circuit of the power source 10, which turns on the welding current pulse 1, melting weld edges. In this case, the axes of the arc and the electrode coincide. The welding arc moves at a constant welding speed.

The moment of switching on and off of the welding current pulse is set from the generator 5 of an external magnetic field. As soon as the intensity of the magnetic field begins to increase, the pulse of the welding current is turned off and the arc on the section G – D (Fig. 2) is deflected by an angle of a predetermined magnitude with a speed v. Then the cycle repeats. Example. Argon-arc welding of samples from Art. 15XM

5 thick 10 mm, with a groove 30 and blunting 1.0 mm, assembled without a gap. The first pass was welded without filler wire, moving the electrode along the axis of the joint.

0 Welding of subsequent passes is done with filler wire. The welding speed on all passes was V (, g 2.1 mm / s, warming arc stand-by current 1, 40 A; current magnitude

five

0

50

0.2 mm. After deflection of the duty-45 in pulse 1 180 A, the time deflected by an angle forward by a specified amount, the strength of the magnetic field in section B-B (Fig. 2) is reduced to zero in a time of 1.8 s while the electrode is moved from a constant welding speed v jg Const 2.1 mm / s. The welding speed is chosen such that during the existence of the pilot arc in section A-B (Fig. 2), the electrode moves a distance equal to the deviation of the pilot arc by the angle ahead and to the moment when the magnetic field strength is zero, it is above the heating point.

no arc on duty at the beginning of the cycle CO, s, the speed of movement of the active spot of the arc at the beginning of the cycle is 40 mm / s, the time of existence of the arc of arc based on its movement at the beginning of the cycle is 1.9 seconds, the time of stabilization of the arc at the heating point. - H 1.8 s, the speed of movement of the active spot of the arc during its stabilization V o, the time of the current pulse

, 8 s, the maximum intensity of the external magnetic field H 21 E. At this value of the external magnetic field strength

in a pulse of 1 180 A, the time of

no arc on duty at the beginning of the cycle CO, s, the speed of movement of the active spot of the arc at the beginning of the cycle is 40 mm / s, the time of existence of the arc of arc based on its movement at the beginning of the cycle is 1.9 seconds, the time of stabilization of the arc at the heating point. - H 1.8 s, the speed of movement of the active spot of the arc during its stabilization V O, the time of the current pulse

, 8 s, the maximum intensity of the external magnetic field H 21 E. At this value of the external magnetic field, the active spot of the arc deflected forward from the axis of the electrode by 4 mm. In these modes, the diameter of the weld pool is 6 mm, which provides overlapping during penetration.

A metallographic analysis of cracks in the weld metal and heat-insulating material was not found.

Compared with the known, the proposed method increases the range of weldable alloys by preventing the formation of cracks in the weld metal and heat-affected zone.

Claims (1)

Invention Formula An arc welding method in which the arc is deflected by a transverse magnet Hk 5 In g 9 C / VAf T So mn Vc6 c8 Editor L.Gratillo Figg Compiled by V.Morochko Tehred M.Hodanich Order 1456/18 Circulation 921 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 five field along the weld axis with an angle of forward, and the electrode is displaced with a welding speed, characterized in that, in order to improve the quality of welded joints during pulsed welding with a pilot arc by preheating the edges being welded, the pilot arc is deflected by a pulsed transverse magnetic field, and when the arc on duty deviates, the magnetic field weariness is reduced to zero, and at the time the electrode end coincides with the point of stabilization of the active arc, a pulse of welding current is switched on, then the cycle Onen pilot arc repeated. BUT ffc) % Ggs) H ss) Corrector G, Reshetnik Subscription