SU988490A1 - Method of arc welding of butt joints - Google Patents

Description

(54) SPOSSAG ARC WELDING OF JOINT CONNECTIONS

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The invention relates to methods of arc welding, mainly of thick-walled joints, with filling filled with feed into the welding bath of an additive metal, and may find application in shipbuilding, power engineering and other industrial sectors.

When welding these products, welding performance is important. The welding capacity, in turn, is determined, especially when welding is performed in different spatial positions, by the volume of the weld pool.

An increase in the volume (mass) of the weld pool during welding in the positions of the different -, jj from the lower one above the critical one leads to the formation of sagging, and at. further increase in mass leads to leakage of the liquid metal.

The known method of vertical automatic welding with oscillations of the electrode along the axis of the joint in three directions: reciprocating in the transverse direction; up and down - back and forth WITH IJ.

However, this method is characterized by insufficient productivity when welding in different spatial positions due to the impossibility of increasing the weld height due to the increased bath length due to the electrode moving back and forth.

There is a known method of vertical autospalach arc welding, in which a burner is placed between the parts to be welded, which performs reciprocating movements rio to the depth of groove, and weld metal is deposited in layers. In the pre-calculated periods. This movement is stopped and welding is interrupted, and then movement is resumed. The arc periodically fades. In order not to initiate the arc again, the maximum and minimum current is used during welding. During the period of minimum current, the hardening of the molten metal is accelerated. To maintain a constant cooling rate at which the mechanical properties do not change

the influence of heat, the indicated periods with the maximum and minimum currents are restrained with a total of 23,

This method is applicable for filling the cutting during welding only vertical - 5 key seams. Using it at cBapite in different spatial positions does not provide maximum performance, because when filling the layer, welding is carried out in continuous mode and, therefore, the length of the bath does not provide the maximum deposition amount.

The closest in technical essence and the achieved effect is the 5th method of arc welding of butt joints with multilayer filling of the edge groove, in which the first and subsequent induction layers are performed with mutually intersecting areas by a uniform back-20 translational movement of the electrode along section 3 J.

The disadvantage of this method is not. the performance of the filling process is optimal, due, firstly, to the difficulty of providing in each layer. the maximum possible size of the cladding and, secondly, with the need to perform several (by the number of layers) passes.30

The purpose of the invention is to increase the productivity when welding seam-edged joints by providing maximum fusion.

The goal is achieved by the fact that, according to the method of arc welding of steel joints with multilayer filling of the groove, at which. . The rum layers are optimally performed by reciprocating movement of the electrode to form mutually overlapping individual sections, the first section of the first layer is performed on a mode 40-50 less than the optimal length (2.0-5) g, Hz E is the length 45 baths at the optimum mode, then the return movement of the electrode for welding the second layer is performed and the welding mode is increased to the optimum one; then the cutting is done by layer-50 but by successive transition from layer to layer, while maintaining a constant distance between the ends of the sections of the next and previous layers and choosing it to be (0.5-2.5) 6, and the next the portion of the precursor layer is carried out at the moment of complete crystallization of the previous portion of this layer.

Moreover, the last section / of the next layer is performed on the mode of the first section of the first layer.

To increase the height of the deposited layer, the areas are formed by separate welding points, the mass of which is maintained within 0.8-0.9 times the critical mass of the bath.

The filling of the cutting is carried out in the direction of welding, and the movement of the electrode from layer to layer in the opposite direction.

The filling of the cut is carried out in the direction opposite to the direction of welding, and the movement of the electrode from layer to layer in the direction of welding.

FIG. Figure 1 shows a diagram of the overlapping of sections in layers along the groove when filling it in the direction of welding; in fig. 2 is a sequence diagram of the indicated process; in FIG. 3 is a diagram of the imposition of welded points when performing welding in a pulsed mode; in fig. 4 - cyclogram of pulse welding; in fig. 5 is a diagram of superposition of the sections along the groove with its filling in the direction opposite to the welding direction; in fig. 6 - the cyclogram of the specified process.

The proposed method is carried out as follows.

Claims (3)

The process of filling the cutting begins with the first section of the first layer. Initially, the area is deposited, when the critical dimensions of the bath (the spontaneous pouring boundary) are reached, the surfacing is stopped: I reduce the current from F to Eu. reduce the speed of the electrode from Vj-g to Vcg. perform idle displacement of the electrode. At the same time, the weld area 1 is crystallized, ensuring good formation of schv. Upon reaching almost complete crystallization of the bath (from these conditions, the values of Djj and VCB are chosen) begin surfacing of section 2. Moreover, the value of 3 and Vj.g is such that the no-load section of the electrode is melted. When reaching the critical size of the bath in area 2, stop surfacing and idle displacement of the electrode is performed. Thus, over a period of time b, a build-up of a number of sections 1-4 is provided, the first section of length (2.0-5.0) 1 is performed. . e., is the bath length at the optimum welding mode, i.e. with the values of Zo and Vc.- Moreover, the welding of the first section is performed on the 4O-5O% less than optimal mode. This is because at the beginning of the welding the metal is not heated and, as a rule, more metal is melted than the base metal is melted. Consequently, at lower values of the welding speed, the bath will reach critical sizes and it may leak out. On modes 40-50% lower than optimal, i.e. The mode in which all subsequent surfacing is performed, the bath has. sufficient volume and does not follow. With mode values less than 40%, the size of the bath is much smaller (welding productivity is low), and with values greater than 50%, the critical sizes, baths, exceed. In the cyclogram (Fig. 2), the required mode is provided by varying the welding speed by 5%. The length of the first section, equal to (2.0-5.0) 6, is chosen from the condition that, when performing surfacing on subsequent layers, to provide a distance between the ends of the sections of the next and previous layers within (0.5-2.5 ) P, i.e. avoid the flow of liquid metal from one bath to another and do not allow it to exceed critical sizes. At the end of the deposition of section 4, the electrode is moved by the second electrode for welding the second layer and the welding mode is increased to the optimum (for which, the welding speed is reduced by 5% to 0%). The surfacing of section 5 on the second layer is performed. When the critical dimensions of the bath are reached (after the time -to), the surfacing of the section is stopped and the electrode is moved with a speed (for-b) in the direction of the first layer (the values of to and. Tj are chosen from the condition of ensuring the subcritical dimensions of the bath and the distance between the ends performance ranges (0.5-2.5) & respectively). The section 6 is deposited on the first layer and the electrode is returned to the second layer and section 7 is then deposited, then 8, 9 and 10 are sequentially deposited over time H; 2. Then, surfacing of sections 1O, 11, and 12 is carried out, making a sequential transition from the first to the second and third layers (Fig. 1). The time -brt may vary depending on the number of layers. After performing surfacing in area 12. the third layer, the electrode at a rate of ce-i (greater VCB) is transferred to the first layer and the cladding of section 13 is performed, then on the second layer of section 14, and the third is section 15. Then the cycle is repeated. The time of the established cycle in multi-layer surfacing is another option (more convenient for automation) of the proposed method presented in FIG. 3 and 4. In this case, the sections are made by separate welding points,. / mass of which is maintained within (O, 8-O, 9) of the critical mass of the bath. Welding is performed in a pulsed mode with a x-shaped displacement of the electrode (during the period of the pulse t, the electrode is stationary, and during the pause period tvi it moves, ayut). Initially, the first portion of the first layer is made as separate non-overlapping points 1, 2, and 3 at a distance of 4 6. Then, the electrode reverses the distance to distance, which, when setting point 4, overlaps between points 1 and 2 (i.e., distance (3-3.5) 6). For a given -b, this is achieved by increasing the speed of the return movement of the electrode Point 4 is deposited, stepped in the direction of welding, then points 5 and 6 are deposited and the electrode is moved back and points 7, 8, 9, etc. are deposited. The distance between the ends of the points of the subsequent and previous layers is provided within; (0.5-1.5) 2. In this case, there is no overflow of the bath of the subsequent layer into the bath of the previous layer. In the first and second embodiments of the welding method, the filling of the groove is carried out in the direction of welding, and the electrode moves from layer to layer in the opposite direction. The third variant of the method is similar to the first with the only difference that the filling of the groove is carried out in the direction opposite to the welding direction, and the movement of the electron from the layer to the layer in the direction of welding. In all the listed options, at the end of welding, the last section of the last layer is performed in the mode of the first section of the first layer. The time of moving the electrode from layer to layer is ensured by the smallest possible, by adjusting the speed of movement, of the electrons. 7 Example. The method was carried out in arc welding with a non-smelting eld in argon medium with feeding of wire joints of pipes made of steel 12X18H10T, 0 18Ох2О m in size. Edging is a step at an angle of 6 mm to open edges. Welding is performed in a pulsed mode with the following parameters: First section of the first layer Pulse current 25 OA Pulse time 1 s Filler wire feed speed 93 m / h Caajvka speed, .17 m / h Filler wire diameter 1, 0 mm Pause current 60 A Pause time 1, 3 s Optimum mode Pulse current 25 OA Pulse time 0.9-1.0 s Welding speed V m / h. Filler wire feed speed 100 m / h Filler wire diameter 1 mm Last section after the last} its pulse Pulse current 25O A Filler wire feed speed 93 m / h Pulse time 0.8 s Welding speed 17 m / h Filler wire diameter 1, 0 mm ki Current pauses 60 A Pause time 1.3 s Filling time for cutting 70 m Number of layers 7 (of which 1 is regional). The filling time of the groove according to the conventional welding technology with a non-consumable electrode with the filing of a filler lead: oxides is 110 minutes. The proposed method provides an increase in productivity when filling up more than 1.5 times. The implementation of the proposed joint venture does not require a substantial increase in the essential control equipment since the process can be easily programmed using 08 simple poeafb units. Claim 1. Method of arc welding of butt joints with multilayer filling of edge cutting, in which the layers are optimally performed by reciprocating electrode movement with the formation of mutually overlapping separate sections, characterized in that, in order to improve the performance of the process, the first section of the first layer is performed on the mode of 4O-5O% less than the optimal length (2, O-5) Ci, where H is the length of the bath at the optimum mode, then the return movement of the electrode for welding second layer and increase the welding mode to the optimum, then fill the layer-by-layer by successive transition from layer to layer, while maintaining a constant distance between the ends of the sections of the next and previous layers and choose it equal to (0.5-2.5) 6 and the subsequent portion of the previous layer is carried out at the time of the final crystallization of the previous portion of this layer. 2. The method according to claim 1, characterized in that the sections are made by separate welding points, the mass of which is supported within (0.8 O, 9) of the critical mass of the bath. 3. Method according to paragraphs. 1 and 2, characterized in that the last portion of the last layer is made in the mode of the first portion of the first layer. 4. Method according to paragraphs. 1-3, in that the filling of the cutting is carried out in the direction of welding, and the movement of the electrode from layer to layer in the opposite direction. 5. Method according to paragraphs. 1 to 3, that is, that the filling of the groove is carried out in the direction opposite to the welding direction; and moving from layer to layer in the direction of welding. Sources of information taken into account in the examination 1. Japanese Patent No. 51-4512, cl. 12 V 106, 1976. 2. Japanese Patent No. 51-36228, cl. 12 B 112, 1976. 3. Kehovsky NI and others. Technologists mechanized and electroslag welding. M., Higher School, 1972, p. 216 Xprotype). 1-2M Satz - Ksw / ..  . A-C / fOtt 2 cS / 1X 15 fai.i SCHSh1GShZHGShLMSH JLJLA-JL Ill f 2 5 five , ji f5 fg 5W J W2.2 5 c / iou Figz t, .. c5 sh L 2 Z i uu til and Jc / iou oi , shchshshshch 9 t 12 13 If FIG. t 5 an upig