SU1053992A1 - Method of arc welding of tee joints by consumable electrodes - Google Patents

Description

The invention relates to welding, in particular, to methods for arc welding by fusion electrode fillet welding, and can be used for welding in hard-to-reach places. Known welding angular necks by the method of deep penetration 1}. To obtain a weld, this method requires special electrodes with cellulose and ilmenite coatings or electrodes with a high content of iron oxide in the coating, and electrodes coated with iron powder, which allow deep penetration to be obtained. Complete cross-section of the weld is obtained in this case in two passes, which increases the complexity of such seams. In addition, the development of these special electrodes is difficult and expensive. At the same time, the seam has a convex shape, which causes stress concentrators when the power flow is distributed from wall to shelf in the structure during operation. This impairs the strength characteristics of the fillet weld. Also known is a method of welding fillet welds using a lining. In this case, the seam is formed in a single pass, having a flexible lining on the opposite side of the electrode l. During the welding process, the floating electrode oscillates in the direction of the wall thickness, the edge of which is pre-cut. The arc current is maximal in the rear part of the wall and shelf edge cutting and is minimal near the specified edges. The disadvantages of this method are the greater laboriousness of the process due to the presence of the lining, butt cutting, the swinging movement of the electrode and the need to use 2 welding modes in hard to reach places. In addition, when the thickness of the welded wall is more than 4 mm, the full cross section of the seam is performed in several passes. . The closest to the technical essence and the achieved effect to the proposed method is the welding of corner joints, in which the wall is mounted on a shelf with a gap, the lining is set and fixed on the lining, the edge and the plane of the elements of the corner joint are melted. The production of electrode benzii922 in the process of welding, forms the seam GZ 1. The presence of the lining, the additional laboriousness of its installation and the oscillatory movement of the electrode during the welding process ultimately leads to a complication of the welding process and an increase in the labor intensity, which is a disadvantage of this method. In addition, if the thickness of the welded wall is mm and a more complete cross section of the seam, it is formed in several passes (i.e., multi-pass welding L, which also increases the labor intensity. Moreover, this method does not allow welding in hard-to-reach places. and reducing its labor intensity while maintaining the strength characteristics of the seam. The goal is achieved by the fact that, according to the method of arc welding with melting electrode of T-joints, including wall installation on the floor a gap with the gap and the location of the electrode between the shelf and the wall at an angle to the wall and to the direction of welding, the subsequent initiation of the arc and the movement of the electrode during the welding process, the gap between the wall and the shelf is set to a a + ", where 8 is the gap between the shelf and dg is the diameter of the electrode, mm; db is the reduction of the gap from welding, mm; a is the correction factor depending on the wall thickness, mm, and the heating spot is placed on the intersection line of the vertical plane of symmetry of the wall with the shelf, heat pattern is moved around Or this line, keeping it on the shelf. The selected gap between the shelf and the wall, together with the proposed electrode location during the process, allows a high-quality corner seam with complete penetration of the entire cross section in a single pass with reverse seam formation without the use of linings, which simplifies the process and reduces labor intensity. The gap between the wall and the shelf ensures excitation and stability of the arc discharge when the arc is located and burning on the shelf below the wall at the point of intersection of the wall axis with the weld axis and moving the electrode along the weld axis without closing it to the wall that ensures the formation of a double-sided seam in a single pass over the entire cross section of the joint. at the selected welding mode. The dependence of the correction factor a on the wall thickness 5, the diameter of the electrode and the transverse one. The shortening of the gap 4 in, depending on the volume of the deposited metal introduced into the gap, is established empirically. In this case, the welding mode, that is, the current strength, the voltage across the arc, the welding speed and the flow rate of protective gas (CO; Ar “SOL”) for electric arc welding with coated electrodes, automatic and hyluo-automatic welding under flux and in protective gases is individual. double-sided seam occurs due to arc burning in the gap, melting the electrode metal and the wall metal and the shelf. If the melting of the metal of the shelf is obvious, since the arc is constantly burning on it, then the melting of the wall end is explained next. When drip transferring molten electrode material, the droplets are detached from the electrode, partially transferred to the bath of molten metal, and partly by the main forces of the welding arc — plasma flows, reactive forces, electrostatic forces, electrodynamic forces in the liquid conductor as well as the magnetic field - A tour that contributes to the removal of a drop of liquid metal on top, by displacing it to the side, wets the end of the wall at the expense of its temperature. it is melted, and the magnetic field of the welding circuit keeps the molten metal in the gap. The arc pressure of the molten metal bath is distributed in the gap in equal portions on both sides of the weld center, forming a monolithic fillet weld in one pass over the entire cross section. In the case of jet transfer of molten metal into the bath by arc pressure when the electrode is tilted at an angle of 32-83, the liquid metal is squeezed upward and wets the end of the wall, melts it, forms an angular welded joint in a single pass through the whole section. This effect is achieved when the welding angle is backward. When welded to the angle forward, the effect disappears and the seam is formed, but the arc pressure is of poor quality. . Thus, the simple set of operations is a certain gap, the location of the electrode at the point of intersection of the wall axis with the weld axis, keeping it on the shelf without hesitation during the arc burning process and metal melting, in combination with the physical processes taking place in the arc column and By transferring the molten metal to the bath of the liquid metal, as well as by the dynamic properties of the current source, a high-quality double-sided seam is obtained in a single pass. This simplifies the process, increases the productivity of labor and provides high-quality weld when welding in hard-to-reach places. Figure 1 shows the relative position of the wall, shelf and electrode in the welding process; figure 2 is the same, top view; on fig.Z butt connection of elements of different thickness, where more thick item plays the role of a shelf. The method is carried out as follows. Wall 1 is placed on shelf 2 with the help of latches or electric lifters forming the required 1G.1 gap. In olj “Dbth, where dg is the diameter of the valve; mm :, and - correction factor for wall thickness, mm :, 48 - lateral shortening of the gap during the welding process, which depends on the volume of the weld metal at certain wall thickness and the gap formed. Electrode 3 is positioned at an angle to the wall and shelf, placing it on the wall at the intersection point of the wall axis with the axis of the seam. Excite the arc at this point and move the electrode along the axis of the seam while holding the arc constantly on the junction. In this case, a bilateral seam is formed in a single pass without the use of linings. In the case of welding of butt joints of parts of the same thickness, the use of terminal strips is required. Terminal strips prevent the molten metal from flowing off during the welding process, as if expanding the shelf. .

Known equipment is used to implement the method.

Examples of the implementation of the method and the choice of the diameter of the electrode c, the transverse shortening of the gap gV and the correcting coefficient for manual electric arc welding with coated electrodes are presented in Table 1; during automatic welding under a layer of flux and in protective gas - in table 2; with semi-automatic submerged arc welding - in Table 3; when semi-automatic welding in a protective gas environment in the table.4. Table 5 presents the welding modes.

Table 1

Coefficient taking into account the thickness of the metal

The gap between the shelf and the walls, Coi & / mm

Shrinkage from welding D In, mm

Electrode diameter dfa, mm

The coefficient taking into account the thickness. metal a

The gap between the wall and the shelf 6; mm

O.k

0.3

6.0

7.0

1.6

1.8

, B7

. 0.65

0.7

0.55

8.0

6.0

7.0 Values included in the formula

1.52 2.0

0,

ii.O

Manual arc welding with coated electrodes 2,055-65 50-6050-60

3.0 110-115 95-115 95-120, 0 165-175 125-135 1 "5-155

Table 3

1.6

1.8

1.7

2.0

2.0

2.0

1.7

0.7

1.2

".ABOUT

6.0

5.0

Table D ... PG-L1G ... Thickness of metal, mm

5.0 180-195 170-185 175-190 Automatic welding under a layer of flux and in protective gas

320-350 ..520-570 700-750 Semi-automatic submerged-arc welding 2.0 320-3 0 - 30-32 Semi-automatic gas-shielded welding

. The technical and economic efficiency of this method as compared with the basic object adopted as a prototype is that the method does not require the use of liners, additional welder transitions to make a reverse seam, like this, to form a double-sided seam; as a double-sided seam, in one pass. This significantly increases labor productivity, which leads to a decrease in the number of employees.

The possibility of a double-sided seam in one pass allows

16-17 22-23 38-39

10-12

use the method in hard-to-reach places without additional equipment and accessories. The quality of the seam, as established by experiment, remains high. Thus, this method makes it possible to manufacture parts of a complex configuration that are welded rather than cast, which reduces the cost of producing such parts.

From the above it is seen that the proposed method is less time consuming and more simple than the known one.

X

V

I

//z.J

Claims (1)

METHOD OF ARC WELDING BY FLOATING T-SHEET COMPOUNDS, including mounting the wall on a shelf with a gap and positioning the Electrode at an angle to the wall and to the welding direction, subsequent arc excitation and electrode movement during welding, that, in order to reduce the complexity, the gap between the wall and the shelf is set equal B "<I _E + ΔΒ + and where B is the gap between the shelf and the wall, mm; <3 _Oe - electrode diameter, mm; ΔΒ- reduction of a gap from welding! mm; a is a correction factor depending on the wall thickness, mm, and the heating spot is located on the line g of intersection of the vertical plane of symmetry of the wall with the shelf, while the heating spot is moved along this line, holding it on the shelf. SU, 1053992 I 1053992 2