SU755485A1 - Backing for shaping welding seam - Google Patents

Description

The invention relates to arc welding with oscillating electrodes at the same time of two welds in T-joints and can be used in various industries.

A known gasket for the formation of a weld, consisting of three longitudinal strips made of materials with different degree of thermal conductivity, which allows to obtain different heat dissipation in different parts of the joint across the weld, but constant along the length [1]. 15

This gasket is designed to form the root of the seam. Its use makes it possible to increase the productivity of the process when welding large thicknesses of aluminum alloys. The middle strip forming the root of the seam is made of a heat-conducting material, and the two side bands are made of low heat-conducting material, mainly in the form of flux-like pads that retain heat.

However, this lining cannot provide, even when welding with oscillating electrodes, the formation of a weld directly on the joint.

2

Ke of the parts of the T-joint without displacement in the direction of the wall, since the central strip of the lining of high-heat conductive material does not provide proplav shelf of the joint, and two side strips - alternating heat removal along the seam in accordance with the oscillations of the electrodes. Consequently, a high-quality welded joint cannot be obtained.

The aim of the invention is to improve the quality of the weld and the reduction of deformations when welding T-joints with two oscillating electrodes by variable heat sink in accordance with the oscillations of the electrodes.

This goal is achieved by the fact that the central strip of the lining is made of non-heat-conducting material, and the two side - of staggered sections of materials with high and low thermal conductivity, and the length of the sections is determined by the formula

0

I

3

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four

where I is the length of the sections, mm

ν - welding speed, m / h,

G - frequency of oscillations of electro

Dov, cycle / min.

FIG. 1 shows a sectional lining for mounting the T-joint, shown by a dotted line, top view / in FIG. 2-4 - the location of the electrodes and sections of the lining at different points of welding.

The lining for the formation of a weld in automatic welding of T-joints consists of three strips arranged along the weld, the middle one of which is located in the center of the liner, and the other two are symmetrically on both sides relative to the welding line. The last two consist of sections 2, 3 arranged in a checkerboard order. To ensure the proplav of the joint flange directly below the wall edge, the central strip of the lining is made of non-heat-conducting material, such as asbestos cement, and its width is determined in. depending on the thickness with? the walls 4 of the joint and the size of the legs K of two welds, i.e. n = (G + 2k. One of the sections of the side bands is made of high-conductive material with a thermal conductivity of the order of> 0.42, such as copper alloy, and the other section of low-conductive material with a thermal conductivity of about 0,017-0,019, such as titanium. alloy The dimensions of sections 2 and 3 along the length of the seam are related to the oscillation frequency of the burners and the welding speed. This is due to the fact that the degree of heat dissipation must be determined in certain areas. Cross-section of the seam in accordance with the direction of each burner to the shelf or on the joint wall and should be kept constant until the position of the burners changes.Thus, when the burner 5 is directed to the joint shelf (see fig. 3), when moving away from the wall, the melting in the shelf should be less than directly below the wall, when both burners are directed to the corner of the joint, in order to slightly reduce the penetration of the shelf, at the time the burner is removed from the wall, a section of low heat conductive material (λ ~ 0.019), for example, titanium alloy, is located under it. At this time, the burner 6 is directed to the wall of the joint, where the fusion is not needed. Therefore, under the connection on the side of the burner 6 there is a section of high heat-conducting material (L> 0.42), for example, of a copper alloy. Consequently, the length of sections depends on time, c. the flow of which each of the burners moves along the shelf or wall of the joint, i.e. associated with the welding speed and the oscillation frequency of the burners. The greater the welding speed, the greater the distance each burner will be along the shelf or wall, which means that the length of the sections will be greater. The more often the burner oscillations, the less time each burner is directed to the shelf or to the wall of the joint. Hence, the length of the sections will be shorter.

Since in one cycle of oscillations each burner has a direction to the shelf and to the wall of the joint, there are two sections with different thermal conductivity on the side of each burner. Consequently, the dependence of the length of each section on the oscillation frequency and the welding speed can be expressed by the formula

^Ζ '~ 2ΐ'

where E is the section length, mm;

G is the oscillation frequency, cycle / min; ν - welding speed, m / h.

For example, with a welding speed of 20 m / h and a burner oscillation frequency of 10 cycles / min, the length of the sections should be

V 333.3

Е = - = —-- = 17 mm

2 Е 2,10

Welding tdvrovogo connection on the attached lining as follows.

When the burners 5 and 6 are directed to the corner of the T-joint (see, Fig. 2), due to the fact that there is a central strip of a lining made of non-heat conducting material under the burners, the required melting in the connection shelf will take place. And the two side strips. At this time, under the burners are the boundaries between the sections. FIG. 3 burner 5 is directed to the shelf, and burner 6 is directed to the joint wall. Accordingly, the burners have sections of low-, heat-conducting and high-heat-conducting materials, which allows a small amount of heat to be diverted from the side of the burner 5 to reduce penetration of the shelf and a large amount of heat from the side of the burner 6 for small penetration of the joint wall. Then the burners 5 and b are again sent to the corner of the T-joint and. further, continuing the oscillatory motion. burner 5 is directed to the wall, and burner 6 is directed to the junction shelf. The position of the lining sections changes accordingly, i.e. on the side of the burner 5 there is a section of highly heat-conducting material, and on the side of the burner 6 it is made of low heat-conducting material. The heat sink also changes accordingly.

The use of a heat sink that is variable along the seam for two-arc welding of T-joints with oscillating burners makes it possible to obtain the formation of a seam in place

five'

755485

joint of parts, good fusion, lack of undercuts and excludes warping of the welded joint.

Thus, as a result of the proposed lining, high quality of welded joints is ensured and an additional mandrel operation is eliminated.

Claims (1)

Claim The lining for the formation of the weld, consisting of three longitudinal strips made of materials with different degrees of thermal conductivity, characterized in that, in order to improve quality and reduce deformations when welding T-joints with two oscillating electrodes by alternating heat sink in accordance with the oscillations of the electrodes, the central band the lining is made of warmth · 5 of the wire material, and two side - from staggered sections of materials with high and low thermal conductivity, and the length of the sections is determined by , 0 formula where I is the length of the section, ~ mm} ί - oscillation frequency, cycle / min ν - welding speed, m / h. . _