RU2262425C1 - Titanium alloy electric arc welding method - Google Patents

Abstract

FIELD: automatic welding increased-thickness joints of titanium alloys in inert gas by means of submerged tungsten electrode.

SUBSTANCE: method comprises steps of forming in welded edges cutout which is in the form of П-shaped dressing of edges at welding parts with slit gap; keeping relation of depth of dressing to its width less than 1; rounding acute angles of dressing; before welding introducing granulated additive material into slit gap and performing first pass at minimally admissible value of shape factor of fusion. In order to provide guaranteed fusion of walls, second and third passes are realized in the same mode. Electrode is placed in such a way that it is shifted relative to butt axis. At double-side welding passes are realized according to next order: first and second passes, then third, fourth and fifth passes.

EFFECT: enlarged manufacturing possibilities of method due to increased limit thickness of welded parts.

3 cl, 5 dwg

Description

The invention relates to automatic welding of active metals in an inert gas environment by a submerged tungsten electrode and can be used in mechanical engineering when welding joints of predominantly increased thickness.

It is known that for welding with a surface arc of joints with a thickness of more than 6-8 mm, multi-pass welding with different preparation of the edges of the parts to be welded is used (GOST 8713-70 "Weld seams. Automatic and semi-automatic welding").

The disadvantage of this method is the danger of deterioration in the quality of the weld due to oxidation (if the protection of the seam is violated for any reason) of the surface of the roller and the transition of oxides into the weld metal during subsequent passage. Repeated cleaning of the weld surface before each pass, followed by degreasing and drying, leads to an undesirable increase in the duration of the production process.

Closest to the claimed technical solution adopted for the prototype is a method of welding titanium alloys with a submerged tungsten electrode along a slit gap filled with granular filler material (see SU 1838061 A1, B 23 K 9/167, 08/30/1993).

The disadvantages of this method include the lack of the possibility of single-pass welding of joints whose thickness exceeds the limit for the selected welding equipment (power source).

The claimed invention is aimed at expanding the technological capabilities of the method of welding by immersed tungsten electrode by increasing the ultimate thickness of the welded parts.

The essence of the claimed invention lies in the fact that in the method of multi-pass automatic arc welding of titanium alloys by immersed tungsten electrode along the slot gap, in which granular filler material is used, which is poured into the slot gap before welding, a cut is made on the welded edges, which when assembling parts with a gap gap formed in the form of a U-shaped groove of the edges with a ratio of the depth of groove to its width less than 1, while the sharp corners of the groove are rounded.

In addition, in this method for guaranteed filling of the U-shaped groove with molten metal, the second and third passes are carried out in the same mode in compliance with the following ratios Н · k≤30 and у = (Е + 2Н) / 2,

where H is the depth of the U-shaped cutting, mm;

E - the width of the U-shaped cutting, mm;

k is the melt shape coefficient;

y is the displacement of the tungsten electrode from the axis of the joint, mm

In addition, in this method, the rounding of the edges of the U-shaped grooves is performed corresponding to the cross-sectional shape of the weld in the second and third passes.

The invention is illustrated by drawings, where Fig. 1 shows welded edges with a U-shaped cut, assembled with a gap in the gap for double-sided welding; figure 2 - the implementation of the first pass; figure 3 - the implementation of the second pass; figure 4 - the implementation of the third passage; figure 5 - the execution order of the passes in two-sided welding.

The main geometric parameters for cutting edges (E, H, and t) depend on the thickness of the metal being welded δ and the characteristics of the welding equipment used. The width of the U-shaped groove E is the sum of the samples at both edges S and the width of the gap gap t. The value of E is chosen equal to the width of the weld (in its upper part), b - in the second and third pass or with slight deviations from b. In a U-shaped cut, the greatest danger to guaranteed penetration is represented by sharp corners (shown by a dotted line in FIG. 1). Therefore, sharp angles are rounded, and the angle of inclination of the rounding is selected based on the shape factor k or experimentally.

The method of automatic arc welding of titanium alloys with a submerged electrode is as follows. On the welded edges, a cut is made in advance, which, when assembling parts with a gap, is formed in the form of a U-shaped groove with a ratio of depth of cutting to its width less than 1. Then, the gap is filled with granular filler material and the first pass is performed (Fig. 2) the minimum possible value of the melt form factor.

If necessary, the surface of the weld after the first pass is cleaned with a wire brush, followed by degreasing and the U-shaped cut is filled with granular material of the same composition as in the gap gap, or of a different chemical composition. For guaranteed penetration of the walls of the grooves and subsequent overlap of the weld from the second and third passes, the electrode is installed with an offset from the axis of the joint y = (E + 2H) / 2 (Fig. 3), and the shape factor of the melt k is selected depending on the sample depth H by the formula N · k≤30. The shape factor of the melt is changed in the right direction by changing the geometric parameters of the tungsten electrode and the depth of its penetration. The third pass is carried out in the same mode as the second (figure 4).

The proposed welding method using a submerged tungsten electrode allows 1.5 times to increase the thickness of the welded metal.

Claims (3)

1. The method of multi-pass automatic arc welding of titanium alloys by immersed tungsten electrode along the gap gap, using a granular filler material, filled before welding into the gap gap, characterized in that a cut is made on the welded edges, which is formed in the form of parts with a gap gap in the form U-shaped cutting edges with the ratio of the depth of cutting to its width less than 1, while the sharp corners of the cutting round. 2. The welding method according to claim 1, characterized in that for guaranteed filling of the U-shaped groove with molten metal, the second and third passes are carried out in the same mode in compliance with the following ratios: Н · k≤30 and у = (Е + 2Н) / 2 where H is the depth of the U-shaped grooves, mm; E - the width of the U-shaped cutting, mm; k is the melt shape coefficient; y is the displacement of the tungsten electrode from the axis of the joint, mm 3. The welding method according to claim 1, characterized in that the rounding of the edges of the U-shaped grooves is performed corresponding to the cross-sectional shape of the weld in the second and third passes.

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