SU1798082A1 - Method for single-sided automatic submerged arc welding - Google Patents

Description

The invention relates to methods for one-sided automatic submerged arc welding with reverse forced formation of a seam and can be used in shipbuilding, chemical, petroleum, transport, power engineering in the manufacture of welded sheet and hull steel structures.

The aim of the invention is to improve the formation of the weld when welding at a variable gap between the edges of the product.

On Fig, 1 presents a General view of the welding machine for performing the welding method; in FIG. 2 is a section AA in FIG. 1; in FIG. 3 - slider with forming a back seam part; in FIG. 4 is a section BB in FIG. G; in FIG. 5 is a plan view of FIG. 3; in Fig.6 is a diagram of a welding process; in FIG. 7 - dependence of the welding speed on the size of the gap in a particular joint at a thickness of 10 mm; in FIG. 8 - dependence of the ripple frequency of the SVA 1798082 A1 even current on the gap value of the specific welded joint at a thickness of 10 mm.

The method is as follows.

A welding machine with a mouthpiece 1. A mechanical copier 2, a spring-loaded roller 3 connected to a sensor 4, a suspension 5 connected to a knife 6 and a forming device 7. consisting of a body 8, surfaces 9 and a slider 10, are mounted on the welded joint, the flux is poured onto surface of the product and excite the arc. The flux through the gap between the sheets to be welded is fed to a slider 10, pivotally connected to the housing 8 by a hinge 11, into the groove 12 with a recess 13 along the inclined surface 14, and the slider 10 is transversely vibrated by the vibrator 15 connected to it relative to the hinge 11. Melting the flux into in the melting space of the welding arc, the protective slag layer between the arc and the slider 10 is fed with molten slag and the forming groove 12 is filled as the slag accumulates and is displaced by the arc from the 25 accumulator. Welding is carried out along the enlarged sublayer 16 with stabilization of filling the gap with molten metal and the depth of penetration of the edges by automatically adjusting the welding speed 30;. and using a pulsating arc with two energy levels.

A characteristic feature of the process of one-sided welding on a moving slider is the slagging of the forming groove on the side of the head of the slider with the formation of a slag visor 17, which prevents the flux from entering the slider, and when welding along the increased slag sublayer, and into the accumulator. The activation of the supply of ^J flux to the melting space of the arc and to the slider, the transportation of slag and molten metal from the arc to the forming part of the slider, the formation of the return roller in the crystallization zone is achieved by regulating the vibration of the slider (frequency and amplitude) and pulsating welding mode. Slag visor 17, formed by burning an arc with a low energy level with a melting ^! by the space of the 1st, which accumulates on its boundary, it melts during the transition of the arc, not a higher energy level with the melting space II, realizing a complete penetration of the edges of the joined - ^! without damaging the forming device with a short-term pulse (0.3-1.0) s and ensuring periodic restoration of the process of supplying flux and slag to the slider 10 during the transition to an arc of low energy level.

The receipt of slag in the forming part of the slider 10 becomes periodic in nature, improving the formation of a one-sided seam.

Slag visor 18, formed during combustion, arcs with a high energy level, in the further welding process does not affect the formation of the seam. At the same time, the use of a pulsating arc in one-sided welding with a variable gap in the joint allows stabilization of the penetration of the edges and the formation of a reverse weld bead.

The dimensions of the storage ring are selected in such a way that the melting space of the first arc on duty overlaps the inclined platform 14 by approximately half its length. The frequency, duration and amplitude of the pulses of the standby and main arcs depends on the size of the gap at the joint and the thickness of the welded, welded sheets and is selected empirically. A groove with a cylindrical surface and dimensions linearly increasing from the beginning to the end of the slider facilitates the movement of the melt into the forming tail portion of the slider and its concentration along the axis of the forming groove, the free passage of the slider along the formed back roller without scoring, the pressing of slider 10 from the sheets to be welded and obtaining the optimal geometry back side of the seam. The gap between the lower plane of the sheets to be welded and the upper surface of the slider 10, created by the protruding supporting surfaces 9 of the housing 8. Provides the possibility of lateral movements of the slider under the influence of the vibrator 15 and reduces the likelihood of undercutting from the groove extruded to the periphery 12 and the back roll of the joint quickly hardening along the edges slag. In this case, the welding speed and the pulsation frequency of the arc should be inversely proportional to the size of the gap in the joint. Changing the welding speed and the arc pulsation frequency is inversely proportional to the gap size ensures filling the groove with electrode metal, significantly stabilizes the heat input into the base metal, the penetration of abutting edges (the width of the weld back roll) and the formation of a one-sided weld.

The slag formation control system on the slider with large gaps is implemented as follows.

With an increase in the gap at the junction, the length of the weld pool increases linearly. It was experimentally established that the lengths of the weld pool when welding in a variable gap with an adjustable speed do not exceed the values determined by the expression! In X (7-8)

The presented expression defines the condition for preventing the weld pool from draining from the rear end of the slider with equal lengths of the forming part and the length of the bath 1v 1pf. Under the condition of optimal formation of a seam along the entire length of the gap

Ιπ.φ ^{s +} ^ .- x (7 - 8), bathtubs and metal outflow from the slider onto.

large gaps.

When welding along small and medium gaps in the joint, the formation of the back side of the seam occurs in the middle of the forming groove using vibration.

The dimensions of the reverse roller at large gaps are slightly larger in width, because the formation occurs in the wider part of the slider groove, however, do not go beyond the existing tolerances.

Prizewinners of performing One-sided welding of sheets with a variable gap in joints 15. ke are shown in FIG. 5 and tab. 2

Using the method improves the quality of one-sided welded joints. to expand the range of welding fluxes with a transition to a more basic, increasing the operational characteristics of welded joints, but having worse, compared with the used acidic fluxes, forming properties.

Claims (2)

CLAIMS 1 wherein _R f is the length of the forming portion of the slider (the distance from the projection center of the arc spot on the surface of said slider to its trailing mechanical cutoff): amax - m ^ ksimal no tolerance gap in the junction. Stab. Figure 1 shows the modes of welding with a stationary arc of butt joints with increased tolerance for the assembly-welding gap (from 2 to 9 mm) and the length of the weld pools calculated according to the presented dependencies. The calculated values of the weld pool lengths slightly exceeded the actual ones. Due to the selection of coefficients, the 35 flux-forming grooves are carried out due to the selection of coefficients, they are poured in the process of welding through a gap in 7-8, with some margin to ensure that the bath does not leak from the slider 10. Method of one-sided automatic submerged arc welding of sheet joints with the forced formation of the back side of the seam on a slider moving with the welding head with a forming groove, in which filling the slider and main arcs corresponding to the currents, with simultaneous transverse vibration of the slider in the plane of its movement, from the beam I have the fact that. 45 edges, in the area directly under the arc create huts. the flux current, and the welding is performed by a pulsating tail, which crystallizes from below with a 40 arc at two energy levels, when the excess slag is removed from under it under hydrostatic pressure of its upper liquid part and vibration, it settles onto the forming surface of the slider 10. Necessary to protect the cooling back roller from oxygen, the amount of slag is held on its surface by the forces of adhesion and surface tension. Due to the use of vibration, the zone of temperature separation of metal and slag turns out to be wide enough that, subject to technological discipline during welding, eliminates welding failures in order to improve the formation of the weld when welding along a variable gap between the edges of the product, the welding speed and arc pulsation frequency are chosen inversely proportional to the gap size between the edges, and the length of the forming part of the slider is chosen equal to the product of the arithmetic mean of the maximum gap between the edges the thickness of the welded components to the proportionality factor of 7-8. 7 1798082 8 The modes of one-sided welding of joints with a variable gap and the estimated length of the weld pool Table 1 The thickness of the welded metal s, mm Current type, polarity Diameter of an electrode, mm The gap at the joint a, mm Welding current I, A Arc voltage U, V Welding speed and _sv at nominal clearance (a, mm) m / h Weld pool length, mm 10 + 10 12 + 12 14 + 14 16 + 16 Permanent arr. polarity Also Permanent arr. polarity Also 2 - 5 .4-6 5 - 7 7-9 2-5 4-6 5-7 7-9 2-5 4-6 5-7 7-9 2-5 4-6 5-7 7-9 2 - 5 4-6 5-7 7-9 600 600 600 600 650 650 650 650 750 750 750 750 850 850 1 26 (3) 23 (3) 30-36 38 - 44 42 - 48 49 - 56 38-44 45 - 52 49-56 56 - 64 2-5 4-6 5-7 7-9 900 900 900 900 1000 1000 1000 1000 21 (4) 20 (4) 17 (4) 16 (5) 49-56 52 - 60 ’ 56-64 63-72 56-64 59 - 69 63 - 72 70-80 66-76 66 - 76 70 - 80 77 - 88 73-84 73-84 77-88 84-96 table 2 Examples of one-sided welding of sheets with a variable joint gap C έ'ε. The thickness of the welded metal, mm Joint clearance mm Welding current, A Arc ripple frequency, mm • Arc voltage, V 2-5 * 500-650 2,5 32-36 4-6 2.0 1 6 5-7 1.4 7-9 and 1.25 2-5 * 600 - 750 2,5 33 - 34 2 8 4-6 2.0 5-7 1.4 - ·· - 7-9 1.25 Continuation of the table. 2 No. The thickness of the welded metal. mm 10/ Joint clearance mm Welding current, A Arc ripple frequency, mm Arc voltage, V 2-5 * 700-900 2.5 34-40 4-6 _ and 2 5-7 _ It 1.4 - 7-9 1" 1.25 2-5 * 850-1000 2,5 36-41 4-6 2.0 ’5-7 - ¹ '- 1.4 7-9 about 1.25 2-5 * 890-1100 . 2.5 ' 38-43 4-6 1" 2.0 5-7 eleven 1.4 G1 7-9 1.25 Continuation of the table. 2 No. p / p • Welding speed, m / h Slider vibration frequency, Hz The amplitude of the transverse movement of the tail torus of the slide, mm The length of the forming part of the slider 1 pf, mm Weld pool length. mm 26 20-25 1.5 60.0 31 22.2 - and_ eleven · 35 ¹ 20.5 if 40 18.6 n 45 23 20-25 1.5 68 35 20.2 • n n - ^and -. 42 2 18.2 and 45 16.5 __ μ _ AND fifty 21 20-25 1.5 76 38 18.5 It. n 45 ³ 16.6 and 51 L fifteen n 58 20 20 - 25 1.5 84 41 17.6 <1. __ eleven 45 3 15.8 eleven - P 51 14.3 eleven __ _to 60 11 1798082 12 Continuation of the table. 2 No. p / p Welding speed, m / h Slider vibration frequency, Hz Amplitude of transverse * movement of the tail torus of the slider, mm The length of the forming part of the slider I π.φ., / ΜΜ Weld pool length, mm 17 20-25 1.5 92 47 fifteen and 54 5 13,4 It , "· · 62 12,2 „N 66 Note. Welding modes are given for welding carbon low-alloy steel with a wire with a diameter of 4 mm at straight polarity for AN 37P flux. . Welding was performed by a pulsating arc with a constant feed speed of the electrode wire. The pause and pulse durations were set on the regulator of the welding cycle the same. When using fluxes AN-348 and OSTs-45, to determine the length of the forming part of the slider, it is necessary to use the coefficient Ί. At maximum gaps, slag runoff was observed. FIG. 8