SU1523278A1 - Method of electric arc welding - Google Patents

Abstract

The invention relates to electric arc welding and can be used in welding long seams in mechanical engineering in the manufacture of railway tank boilers, pipes and in shipbuilding. The purpose of the invention is to improve the quality and productivity of the process. Welding are two wire electrodes located across the bath. Power is supplied from a single source. The electrodes are pre-bent and fed at an angle of 80-90 ° to the side edges of the groove. Feed at an angle of 80-90 ° reduces the arc pressure in the area of the gap in the joint and ensures the retention of the liquid metal on the edges of the bath when welding with increased speed. 1 ill., 1 tab.

Description

The invention relates to the field of electric arc welding of large extent seams such as tanks, pipes, etc.

The purpose of the invention is to increase the productivity of the process and ensure the high-quality formation of welds in single-sided welding on a flux cushion.

The drawing shows a process diagram.

The method of arc welding is carried out as follows.

Two wire electrodes 1 are fed to the arc burning zone by one feed mechanism. At the outlet of the mouthpiece 2, a current-carrying prism located between the electrodes is fastened to it, under the action of which the electrodes are bent and supplied at an angle of 80-90 ° to the side edges of the bath 3. This angle is provided by the angle at the apex of the prism. The electrodes are shorted to the product, covered with a layer of flux and excite the arc. During the welding process, the electrodes are fed at the same speed; during bending, a reliable current lead to the wire electrodes is provided.

The feed at an angle of 80-90 ° to the side edges of the groove reduces the arc pressure in the area of the gap in the joint and ensures the retention of the molten metal on the edges of the bath when welding with increased speed. The maximum pressure of the arc coincides with the axis of the electrode; therefore, when bending the electrodes, the maximum pressure shifts from the gap in the joint to the side edges of the groove, which leads to a change in the forces acting on the liquid metal of the bath.

The arc force becomes perpendicular to the side edges of the bath and prevents the metal from flowing off the edges of the bath. In addition, the direction of the electromagnetic forces acting on the radial current component is changing. Due to the fact that the active spot of the arc shifts from the bottom to the side edges of the bath, this electromagnetic force becomes almost perpendicular to the edges of the bath and, summing up with the arc pressure, ud, holds the liquid metal on the edges of the bath. This ensures the high-quality formation of seams when raising tsD

WITH

to

00

High welding speed and one-sided welding on a flux cushion.

When the electrodes bend and feed at an angle of less than 80 ° to the side edges, the arc pressure in the gap area increases dramatically, and a vertical pressure component appears that blows the molten metal off the edges of the bath, resulting in a formation of a reverse roller when unilateral welding on flux cushioning and the formation of an outer seam due to undercuts.

When bending and feeding the electrodes at an angle of more than 90 ° to the side edges, the active spot of the arc; is located at the level of the upper surface of the base metal, as a result of which the arc pressure blows the liquid metal out of the melted groove, as a result of which the welds are formed and the formation of a seam is disturbed. In addition, with an increase in the bending angle of more than 90 °, the bending and feeding of the electrode becomes difficult, the stability of the feed and welding mode is disturbed.

Example. One-sided butt-weld welding was performed on a flux cushion without cutting the edges of the plates of 9Х 150X900 size from 09G2S steel with a different arrangement of wire electrodes relative to the side edges. The bend angle and the feed of the electrodes were adjusted by changing the angle at the top of the prism. A VMG-5000 rectifier was used as a power source. Welding was carried out with Sv-12GS wire with a diameter of 4 mm on a direct current of reverse polarity under the flux AH-348AM using it for a flux cushion. The results of the conducted research on the effect of the bend angle and the feed of the electrodes relative to the side edges on the performance of the process, the quality of the formation of seams and stability are presented in the table.

As a result of the research

it has been found that bending and feeding the electrodes at an angle of 80-90 ° to the lateral edges is related. The use of the proposed welding method provides the following, -1 duyush, s advantages:

a) increase the speed of automatic welding of butt joints with ensuring

high-quality formation of shvov;

b) high-quality formation of a back roll on a flux cushion with the use of the standard vitreous flux AN-348AM;

c) an increase in the productivity of the process by more than 1.5 times due to an increase in the welding speed and the replacement of the fluo. ice lining on a flux cushion;

d) improving the mechanical properties of welded joints (toughness) by reducing heat input during welding at an increased rate;

e) high-quality weld formation due to reduction of pressure of the arc and downward electromagnetic force.

Claims (1)

Invention Formula The method of electric arc welding with two wire electrodes located across the bath in direct contact and fed from one source, characterized in that, in order to improve the process performance and ensure the high-quality weld formation, electrodes bend and serve at an angle of 80-90 ° .4 side edges. danny. 0 0 a) ne. Welding mode was recorded by recorders. The depth of the undercut to the heights of the back roller was measured by a watch-type tester with a special attachment ..