SU1143547A1 - Method of arc multipass welding of pipe non-turnable joints - Google Patents

Abstract

1. METHOD OF ARC MULTI-PASSWAY WELDING OF TROUBLESHIP TUBES without bevel edges with a non-consumable electrode in shielding gases without filing of filler wire, with a co-torus welding pass is produced by PATHESHUTH P | 7ЕХН1 5 С А: BMBySteKD,. with full penetration of the pipe walls with subsequent execution of auto-pressing passages with incomplete penetration, differing from the fact that, in order to reduce the quality of pipe joints with a wall thickness of more than 4 mm, before making the welding pass, at least two additional passes with incomplete penetration, with This arc is initially placed in the center of the joint in the ceiling position, and then the arc is displaced from the center of the joint to the edges at the transition of the arc to the lower position by 40-80% of the weld seam width, and when cooking passageway in the overhead position with pogonnzto arc energy is increased by 30-50% compared to the energy of the arc heat input in the performance of this passage in the lower position. co wore i4 |

Description

2. Pop. 1 method differs in the center of the butt and with the fact that when it is thickened and then it is shifted to the auto-pressing passages with the edges when welding in the ceiling welding in the lower position, the two-position.

1143547

The invention relates to methods for welding with a non-consumable electrode of non-rotary joints of pipes with a wall thickness of more than 4 mm, preferably without filler wire, and can be used in shipbuilding power, aviation and other industries of national economy. When welding critical structures in these parts of the national economy, increased demands are placed on the quality of the welded joint and on the geometric dimensions of the weld. Therefore, when welding pipe sleeves, various process techniques are used to provide the required weld geometry and quality. The known method of arc multi-pass welding, in which welding is carried out on a constant mode, providing incomplete melting in the trench passage with full penetration and formation of a weld reinforcement during subsequent passes. The disadvantage of the method is an unstable and uneven weld geometry when welding pipes with wall thickness more 2 mm and a diameter greater than 40 mm. The known method of multi-pass welding of pipe joints, in which the perm meter of the pipe is broken up into separate sections and at each section the first pass is performed with incomplete penetration, and on subsequent passages the pipe wall is melted and form a reinforcement t2T. The disadvantages of this method are the unevenness of the geometric dimensions of the seam inside the pipe and the complexity of the process. The closest in technical essence and the achieved result to the proposed is a method of arc multi-pass welding of non-rotary pipe joints, in which the welding pass is carried out with full penetration of the pipe walls with the subsequent auto-pressing passes with incomplete penetration of the Cz pipe walls. The disadvantages of this method are the unevenness of the geometric dimensions of the seam inside the pipe in different spatial positions and obtaining a poor-quality joint — with a wall thickness of more than 4 mm. The purpose of the invention is to improve the quality of the connection of pipes with a wall thickness of more than 4 mm. The goal is achieved by the method of arc multi-pass welding of non-rotary joints of pipes without bevel edges with non-melting electrode in protective gases of filing wire troubles, in which the welding passage is made with penetration of pipe walls with subsequent piercing of auto-pressing passes with incomplete welding of pipe walls Before performing the Welding passage, at least two additional passes with incomplete penetration are performed, and the arc is first placed in the center of the joint when welding e in the ceiling position, and then the arc is displaced from the center of the joint to the edges when the arc moves to the lower position by 40-80% of the width of the welding passage, and when the welding passage is performed in the ceiling position, the heat input of the arc is increased by 10-50% compared to the heat output arc energy when performing this passage in the lower half section. When performing auto-pressing passages when welding in the lower position, the arc is placed in the center of the joint and then shifted to the edges when welding 9 the ceiling position. Such an embodiment of welding a non-rotating joint creates the conditions for obtaining the necessary surfaces of the liquid bath in the lower and ceiling positions, which contribute to a better retention of the bath and high-quality formation of the seam with obtaining the required geometry. Fig. 1 shows the scheme for making additional passes with incomplete penetration; Fig. 2 is a diagram of the welding pass; FIGS. 3 and 4 show the auto-pressing passageway; Fig. 3 is a sequence diagram of the welding mode depending on the spatial position of the arc. The arc multi-pass welding method is carried out as follows. Pipes 1 and 2 are joined without a gap and are attached. Electrode 3 is installed in the ceiling position in the center of the junction 4. The arc 5 is ignited by electrode 3 and pipes 1,2 and the additional conducts 6 are started in a mode that ensures incomplete melting of the wall wall thickness tf tf 1 and 2. Moreover, in the ceiling position arc 5 they are moved along the center of the junction 4 with a gradual displacement of the arc; gi 5 at the edge of the Tube 1 yo program, depending on the spatial position of the arc or due to the slope of the plate. The extensions continuously for at least two additional passages 6, then the additional passages 7 with the displacement of the arc 5 in the lower bottom of the pipe 2. The total depth of the penetration h must not exceed 3/4 of the thickness of the wall of the walls of tubes 1 and 2. The number of additional passes is selected from the height crawl condition. The reinforcement of the cheek in the lower position from additional passes with veggie (0.15–0.2) o ensures that the required surface surface tension of the bath ensures the required amount of force on the surface tension of the bath while keeping the bath from lower in position. The additional prokhots 6 and 7 shift when welding in the lower position on the pipe thrusts, respectively, 1 and 2 for the value of H from l 7. 4 Research Institute of the joint 4, the value of which is chosen equal to 40-80% of the weld width when making the welding passage 8. When shifted by H less than 0.4 V, the seams of the additional passages 6 and 7 overlap significantly and significantly reduce the surface tension of the outer surface. bath when welding passage 8, which leads to unacceptable sagging seam inside the pipe. With a displacement of H greater than 0.8 V, the seams from the additional passages 6 and 7 are practically not melted by the welding passage 8, which also significantly reduces the surface tension of the bath and increases the sag of the seam inside the pipe. When additional passages are made in the ceiling position at the center of the joint 4, a total weld width is obtained, which is almost equal to the width B of the welding pass, which ensures maximum surface tension of the external surface of the bath and minimum sag of the joint inside the pipe. After completing the additional passages 7, the electrode 3 is positioned in the center of the joint 4 and the welding passage 8 is completed in a mode that ensures the full penetration of the thickness of the wall of the pipes 1 and 2. At the same time, the heat input q in the ceiling position. / V increase by 30-50% compared with heat input q / Vpjj in the lower position (figure 5). The increase in heat input is due to an increase in the wall thickness of pipes 1 and 2 in the center of the joint due to additional passes 6 and 7. An increase in heat input of less than Hai 30% leads to an unstable penetration of the pipe wall in the overhead position, and over 50% - to an excessive increase in the volume of welding bath and substandard suture formation. After the welding passage has been completed, the welded joint 4 is cooled and the auto-pressing passes 9 are started. In this case, the electrode 3 is placed in the center of the seam 8 and the electrode 3 is moved to the edge of the seam 8 when approaching the ceiling position, thereby providing almost the same dimensions of the seam surface (B and h), Auto-pressing passes can be performed with oscillations of the arc 4, then it is not necessary to displace the electrode 3 of the seam 8. The method is carried out as follows. The method is carried out when welding non-rotary joints of pipes of size 0 42-5.3 mm from steel 12X18H10T. An OBA-3 pipe welding head is used. Welding is carried out in a pulsed mode from a TIR300 DM power source. A rod of lanthanized tungsten 0–3 mm, sharpened at an angle of 0.5 mm is used as an electrode. Argop is used to protect the electrode and the weld. The pre-plan washer is installed so that the electrode provides overlap. additional passages with a deviation from the joint in the lower position by 3 mm, i.e. 0.6 V, where mm is the width of the welding seam. In this case, two additional passes are provided at each edge. The mode of additional passes: A; KhdeGZO A; , 9 s; tn 0.6 s; 5 m / h; 2 mm. After additional ducts are inflated, the seam reinforcement is 0.9-1.0 mm in the lower position and 1.5 in the overhead position. The electrode is then placed above the joint and a full penetration welding pass is performed. Welding mode: for the lower position A; 1de; 30 A; , 9 s; , 6 s; V 3.5 m / h, for the ceiling position A, the other parameters of the mode are the same. After the welding pass, the seam is reinforced outside and inside the pipe. The dimensions of the reinforcement in the lower position are 0.5-0.6 mm inside the pipe, in the ceiling position 0.10, 3 inside the pipe. Then, two auto-pressing passes are performed in the mode: A, the remaining parameters are the same. The geometrical dimensions of the seam in all positions comply with the requirements of the control rules. The application of the proposed method of arc multipass welding of non-rotary pipe joints allows increasing the wall thickness, welded without cutting edges, up to 10 mm without complicating the pipe-welding machines, ensures high quality of welded joints and stability of its geometric dimensions in all parts of the non-rotary joint.

/

,

one

Fig.Z

(Pi / s.6

Claims (2)

1. METHOD OF ARC MULTI-PROPERTY ^: CIRCUIT WELDING OF NON-TURNING JOINTS PIPE without beveling the edges with a non-consumable electrode in shielding gases without filler wire feeding, during which the welding pass is made with complete penetration of the pipe walls, followed by automatic compression passes with incomplete penetration, characterized in that, in order to improve the quality of the pipe connection, the wall thickness is more 4 mm, before performing the welding pass, at least two additional passes with incomplete penetration are performed, while the arc is first placed at the center of the joint in the ceiling passage, and then the arc is shifted from the center of the joint to the edges when the arc transitions to the lower position by 40-80% of the width of the weld of the welding passage, and when the welding passage is in the ceiling position, the linear energy of the arc is increased by 30-50% compared to the linear energy of the arc when performing this passage in the lower position. J j Μί γή I I II FIG. 7 2. The method according to claim 1, characterized by the fact that when performing auto-pressing passes when welding in the lower position, do 1141447 - gu are located in the center of the joint and then move it to the edges when welding in the ceiling position.