RU2022743C1 - Case-type section structures manufacture method - Google Patents

Abstract

FIELD: welding. SUBSTANCE: using samples of pair by pair assembled pieces with clearance between them, curve of welding current change is determined for the case of structure outer corner seam welding during transition of welding arc over the clearance, size of which corresponds to 1.5 - 2.0 of length of arc. Pair by pair assembled pieces are tightly laid on horizontal plane. Welding of joints of pairs of pieces is exercised, using continuous seam, avoiding zones of pieces conjugation by welding arc according to isothermal curve of welding bath melting temperature. Then pairs of pieces are turned over by 180 deg. and they also weld joint seams of pieces from opposite side by continuous seam, avoiding conjugation of pieces. Once more a row of pairs of pieces is laid so as to form common horizontal line, made by joints of outer corner seams. The seams are welded by continuous seam, using changes of current according to figures of determined curve during transition from one pair of pieces to another. Assembled row they turn over by 180 deg. and weld by continuous seam joints of inner corner seams, using figures of welding current changes according to determined curve of welding current change. EFFECT: method is used for automatic welding of thin-walled structures of case type cross section. 7 dwg ca

Description

 The invention relates to fusion welding and can be used for automatic welding of thin-walled box-section structures in various industries.

 A known method of welding structures of the box section by butt welds [2].

 The disadvantage of this method is that when manual welding of box-section structures, the quality of the welded joint and manufacturing productivity are reduced due to the large number of defects.

A known method of manufacturing structures of box-shaped section, in which the ends of the box-type parts are processed at an angle of 45 ^about , assembled in pairs, and then welded by contact welding [1].

 The disadvantages of this method are the decrease in the quality of the welded joint due to the formation of burr on the surface of the weld, both from the outside and from the inside, an increase in energy consumption due to the use of powerful contact equipment.

 The aim of the invention is to improve the quality of welded joints and reduce energy consumption in the manufacture of thin-walled structures.

This is achieved in that the method for manufacturing structures box section, wherein the box-type ends of parts treated by an angle ^of 45 °, was collected in pairs, and then sealed preferably by arc welding, previously on samples of mutually assembled with a gap parts define a curve change of a welding current under welding of the external fillet weld of the structure when the welding arc passes through the gap between the parts, corresponding to 1.5-2.0 of the arc length, in the assembly process, pairwise assembled parts are tightly laid on a horizontal hydrochloric plane so that the end joint of a previous pair of parts is mated with the beginning of the joint subsequent pair of parts, welding butt portions pairs of parts are continuous seam bypass zones mating parts welding arc along the isotherm weld pool melting temperature and then turn over the pair of parts 180 ^a, and weld the butt seams of the parts on the reverse side with a continuous seam bypassing the mating zones of the parts, then re-lay a number of pairs of parts with the formation of a horizontal common line from the joints of the outer fillet welds all carrying their continuous suture using the determined on samples curve of the welding current, at the transition from one pair of parts to the other, whereupon the collected number of turn over by 180 ^about and sealed continuous seam joint inner fillet welding using the determined on samples curve of the welding current during the transition from one pair of parts to another at the joints of pairs of parts.

 As a result of the analysis of well-known technical solutions during patent research, no technical solutions with features similar to the distinguishing features of the proposed solution were found, and therefore, the combination of the mentioned essential features improves the quality of welded joints and also reduces energy consumption in the manufacture of thin-walled box structures.

 In FIG. 1 shows a General view of the welded parts; figure 2 schematically shows the operation of welding butt welds on a horizontal plane; in FIG. 3 - welding of butt welds on a horizontal plane, top view; in FIG. 4 shows the operation of determining the curve of the change in the welding current when welding the outer fillet; figure 5 - the welding operation of the outer fillet welds; figure 6 - welding of the outer fillet weld, side view; Fig.7 - the operation of welding internal fillet welds.

 The method is as follows.

Pre-weld samples 1 ^I , 2 ^I , 3 ^I , 4 ^I. The ends of the samples 1 ^I, 2 ^I, 3 ^I, 4 ^I box section is treated by an angle ^of 45 °, was collected by pairwise samples 1 ^I, 2 ^I, 3 ^I, 4 ^I and produce weld their butt joints "C" is then set in a row in pairs welded samples 1 ^I , 2 ^I , 3 ^I , 4 ^I with a gap "a" between the pairs of samples and weld the outer fillet weld "A" of each pair to determine the curve of the welding current when welding fillet weld "A", design, at the transition of the welding arc through the gap "a" between samples 1 ^I , 2 ^I , 3 ^I , 4 ^I. Similarly determine the curve of the change in welding current when welding the internal fillet weld "B". It was experimentally established that when determining the curve of the welding current when the welding arc passes through the gap "a" between the samples, the gap should be within a = 1.5-2.0 of the arc length l. This ensures high quality welded “A” welds with good formation. As experiments have shown, with a decrease in the gap "a" less than 1.5 of the arc length l, fusion of the edges occurs. With an increase in the gap "a" more than 2.0 of the length l of the arc, the arc when passing through the gap "a" becomes unstable, the quality of the weld is deteriorated.

For welding parts 1-4, their ends are prepared, for which they are processed at an angle of 45 ^about . Then they are assembled in pairs and tightly laid without a gap in a fixture (not shown) on a horizontal plane so that the end of the joint 5 of the previous pair of parts 1, 2 is mated to the beginning of the joint 5 of the next pair of parts 3, 4 and beyond for all subsequent pairwise laid “n” details. A welding machine (not shown) is installed with a torch 6 and butt welds “C” are welded in pairs of parts 1-4 ... n with a tungsten electrode 7 by a continuous weld with a bypass of the zones of parts 1-4 ... n by a welding arc 8 along trajectory 9 isotherms of the melting temperature of the weld pool.

After the welding of butt joints "c" with one side of the pair of parts 1-4 ... n to turn over ¹⁸⁰ ° and welded butt joints "C" parts 1-4 ... n from the back side continuous seam zones bypassing their conjugation welding arc 8 along trajectory 9.

 Then the parts 1-4 ... n, welded in pairs, are laid without a gap in a row with the formation of a common horizontal line from the joints for welding of the outer fillet welds "A". A welding torch 6 with a tungsten electrode 7 is installed on the outer corner butt 10 and is welded with a continuous seam, and when welding the junction of each pair, the curve of the welding current change found on the samples is used.

Thereafter, a number of assembled parts 1 and 2, 3, 4 ... n to turn over ¹⁸⁰ °. A welding torch 6 with a tungsten electrode 7 is installed and joints 11 of the inner fillet welds “B” are welded continuously using the weld current curve found on the joints of each pair found on the samples for the case of an inner fillet.

EXAMPLES They automatically weld structures made of box-shaped profile 30x40 in size, with a wall thickness of 3.0 mm, from an aluminum alloy AMg3 in a plant with a welding torch ASGV-4 with a tungsten electrode in an inert gas environment, in the mode: I _St. 200 A, welding speed V 18 m / h, argon flow 6-8 l / min;
Prepare samples. The ends of the box-section samples are processed at an angle of 45 ^° , and are collected in pairs. First determine the length of the arc. Weld fillet welds. It was experimentally determined that the length l of the arc when welding with a tungsten electrode in the specified mode upon receipt of welds corresponding to instructional materials is 2.0 mm.

Previously, on samples 1 ^I , 2 ^I , 3 ^I , 4 ^I from pairwise assembled with a gap "a" = 1.2; 1.3; 1.4; 1.5; 1.6; 1.8; 2.0; 2.1; 2.2; 2, 3 of the arc length l determine the curve of the change in the welding current when welding the outer fillet weld when the welding arc passes through the gap "a" between the parts of samples 1 ^I , 2 ^I , 3 ^I , 4 ^I. When the electrode moves to a distance of 2-4 mm from the edge of the part installed with a gap "a", the current begins to fall. When the arc jumps through the gap “a” from parts 1 ^I , 2 ^I to parts 3 ^I , 4 ^{I, the} current to parts 1 ^I , 2 ^I disappears, i.e. the current in the area of the part 1 ^I , 2 ^I adjacent to the gap "a" drops from the values of the welding current to zero. On part 3 ^I , 4 ^{I, the} current is restored from zero to the values of the working welding current.

 The experimental results are summarized in table.

 The isotherm of the melting temperature of the weld pool is also experimentally determined. The dimensions of the welded butt joint of the box construction are experimentally determined. It was experimentally established that the width of the weld is 8 mm and the length of the weld pool is 16 mm.

Ends of parts 1-4. . .20 work at an angle of 45 ^° , assembled in pairs and fit tightly in a fixture (not shown) on a horizontal plane so that the end of the junction of the previous pair of parts 1, 2 mates with the beginning of the next pair of parts 3, 4 and also all subsequent laid parts up to 19 and 20. A welder (not shown) with a torch 6 is installed at the joints 5 and the butt joints of the parts of the pairs of parts 1-4 ... 20 are welded with a tungsten electrode 7, a continuous butt weld “C” with a welding arc 8 with a bypass of the mating zones along the path 9 programmed a automatically for a length of 8 mm on each part 1-4 ... 20 according to the isotherm of the melting temperature of the weld pool, determined experimentally and equal to 8 mm. The arc 11 is displaced in the direction of 4 mm from the interface 5. After the welding of butt joints "C" on the one hand all pairs of parts 1-4 ... 20 device (not shown) to turn over ¹⁸⁰ °, the welding torch 6 with tungsten electrode 7, 5 parts 1, 2 are installed on the joint 5 and according to the recorded program, all butt seams “C” are welded from the reverse side by a continuous seam “C” also with bypassing the mating parts 1-4 ... 20 along trajectory 9.

 Then, parts 1-4 ... 20, welded in pairs by butt welds, are hardly laid for welding with the formation of a horizontal common line from the joints of 10 outer fillet welds “A”. Install a welding torch 6 with a tungsten electrode 7 at the corner butt 10 and weld with a continuous seam "A" using the curve of changes in the welding current found on the samples during the transition from one pair of parts to another.

Thereafter, a number of assembled parts 1-4 ... 20 to turn over ¹⁸⁰ °, the welding torch 6 mounted with a tungsten electrode 7 and produce a continuous seam weld "B" joints 11 inner fillet welds "B" with the curve of the welding current found in samples when moving from one pair of parts to another.

 Thus, in comparison with the prototype, this method of manufacturing box-section structures allows to improve the quality of welded joints of thin-walled structures, as well as to reduce energy costs through the use of arc welding machines instead of expensive powerful contact machines. In addition, the proposed method is easy to automate.

Claims (1)

METHOD FOR MAKING BOX SECTION STRUCTURES, including machining the ends of box-shaped parts at an angle of 45 ^o , assembling them in pairs and welding with a welding arc, characterized in that, in order to improve the quality of welded joints and reduce energy consumption in the manufacture of thin-walled structures, the change curve is first determined on the samples welding current when welding the outer fillet of the structure when the welding arc passes through the gap between the parts, for which the ends of the box-section samples are processed at 45 l ^o, are collected in pairs with a gap of 1.5 - 2.0 arc length and to weld the outer fillet weld, then mutually assembled parts tightly to one another are placed on the horizontal plane, matching the end of the joint parts with the previous pair beginning splice subsequent pair of parts, they weld the butt sections of pairs of parts with a continuous seam, bypassing the mating zones of the parts of the welding arc in a curve corresponding to the isotherm of the melting temperature of the weld pool, then turn over pairs of parts 180 ^o , weld the butt joints of the parts from the reverse side of the weld with a continuous seam bypassing the mating zones of the parts, then lay a series of pairs of parts tightly one against the other and weld them with a continuous seam to the depth of the lack of penetration obtained by welding the previous butt welds, after which the assembled row is turned over 180 ^° and the joints of the inner corner welds with a continuous seam seams to the depth of lack of penetration obtained when welding butt welds.

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