RU2598746C1 - Method and device for vertical fusion welding at slot cutting - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to a method and device of fusion welding of the parts and can be used in all industries for welding by fusion at slot cutting of the large thickness parts. Vertical fusion welding is performed at slot cutting. Cutting is performed with the same width throughout the length of the welded joint regardless of the thickness of the welded parts using the combs, the output hopper and the output plate, which are pre-welded to the welded parts. Device includes vertical guides for movement of the running gear, mechanism of reciprocal movement of the welding torch. Water-cooled forming pad is installed by means of the wedges under the combs of butt joint. Welding head comprises a gas-proof annex with forming water-cooled slide and clamping mechanism.

EFFECT: result is a possibility to perform the vertical welding without preliminary machining of the welded parts edges and without preliminary manual weld of the root to obtain high quality of the welded roots.

2 cl, 2 dwg

Description

The invention relates to arc welding in shielding gases of butt joints of metals and alloys and can be used in all industries for fusion welding by crevice cutting of large thickness parts, including large ones, where this welding method finds application.

A known method of fusion welding according to slot cutting (Rules and regulations in nuclear energy. - Welding and surfacing. - Basic provisions. - PN AE G-7.009-89. - M .: Energoizdat - 1991. - S. 177), in which are welded the edges are made with a bevel angle (the edges are machined mechanically), then the parts are prepared for welding, assembled, tacked and welded. The bevel angle of the welded edges is chosen arbitrarily, which can lead to insufficient or excessive size. The disadvantage of this method is the formation of incomplete fusion in the case when the bevel angle of the welded edges is insufficient, which leads to poor quality of welded joints and the need for their repair. In addition, the disadvantage of this method is to reduce the degree of contact hardening of the welded joint in the case when the bevel angle of the welded edges is made with an overestimated value, and when welding the filler wire is less durable than the material of the parts. This leads to a decrease in the strength of welded joints. In the case when an overestimated value of the angle of inclination of the welded edges during welding used a filler wire commensurate with the strength of the material of the parts, the strength of the welded joints does not decrease, however, a large amount of deposited metal in the welded joint reduces the efficiency of the welding process.

In addition, when using this method for vertical welding, due to the reduced bevel angle, the welded edges of the parts will deviate from the vertical position towards the slit, and the degree of impact of the welding arc on the welded edges will decrease, and if the bevel angle is excessive, the welded edges of the parts will not reach the vertical position, and the ratio between the thickness of the parts and the size of the gap of the groove will increase.

The closest in technical essence to the invention is the fusion welding method for crevice cutting according to RF patent No. 2175906, adopted as a prototype, in which welding is performed on crevice cutting, using the calculated bevel angle, which is performed according to the empirically determined ratio, depending on the total narrowing of the gap width between the edges and the thickness of the parts to be welded. Therefore, first, the welded edges of the parts are machined to obtain the specified bevel angle, then the parts are prepared for welding, assembled, tacked and welded. When welding, the welded edges are installed in a vertical position only at the end of the welding process due to their angular displacement due to uneven thickness of the transverse shrinkage of the parts. The disadvantage of this welding method is the need, depending on the thickness of the parts to be welded, to calculate the bevel angle of the edges to be welded and their preliminary machining, as well as the use of a multi-pass welding method with a non-consumable electrode with filler wire feeding, which significantly reduces the overall cost of the welding process .

A known method of welding in a mixture of shielding gases for gap cutting and a welding machine for implementing this method (journal "Shipbuilding Technology", 1982, No. 9, article "The use of gap cutting when welding joints in positions other than the bottom").

When implementing this method of welding butt joints in slotted cutting, the weld pool is located at a certain angle to the plane of the welded product, and the welding torch reciprocates from the front wall of the product to the back. In addition, to ensure the reliability of fusion of the weld metal with the edges of the product, the burner performs transverse vibrations to provide an angle of inclination of the axis of the welding wire to the cutting plane of at least 10 °. The most stable welding process occurs when using a welding wire with a diameter of 1.2 ÷ 1.4 mm and using a mixture of argon and carbon dioxide (80% argon and 20% carbon dioxide) as a protective medium.

The welding machine consists of a welding tractor with a step motion mechanism and a welding head mounted on the tractor. The welding tractor moves along a guide mounted and fixed on the surface of the product parallel to the longitudinal axis of the welded joint. The welding head consists of a longitudinal movement mechanism in the slotted cutting of the welding torch, a transverse vibrations mechanism of the welding torch, a welding wire feed mechanism and a welding torch.

The main disadvantages of this method and device for welding into a slotted groove are the following:

1. With an increase in the thickness of the sheets to be welded, the width of the gap gap increases and, accordingly, the complexity of welding.

2. When welding into a narrow slotted groove of the root pass, the transverse vibrations of the welding tip of the torch should be carried out around a geometric axis located at a distance equal to half the thickness of the sheets being welded. This is achieved by special, complicated in construction, mechanisms of transverse vibrations of the welding torch (dual parallelogram mechanism or planetary-lever mechanism). These mechanisms must have a very accurate design, eliminating the appearance of backlash.

3. With transverse vibrations of the welding torch, its large part, not included in the gap, has a significant swing range, which makes it difficult to feed the welding wire into the arc burning zone due to its large kink. Therefore, this method and device can be used when welding into narrow slotted cutting edges of parts with a thickness of up to 30 mm.

Known welding machine for implementing a method of welding plate metal in a vertical position by the method of "Cross slide" according to the patent of the Russian Federation No. 2372176, selected as a prototype of the claimed device, according to which the welding machine contains a welding tractor with a step-by-step mechanism and a carriage mounted on it with it mounted a welding head, consisting of a mechanism for longitudinal movement in the cutting of a welding torch, a mechanism for transverse vibrations of a welding torch, a welding feed mechanism wire and welding torch. The welding tractor moves along a guide mounted and fixed on the surface of the product parallel to the longitudinal axis of the welded joint.

The main disadvantages of this device for implementing vertical welding technology are the following:

1. The device does not have a protective-forming lining to protect and form the root of the weld from the inside, therefore, before the process of automatic welding of the vertical joint of two workpieces, additional labor-intensive operations are required for manual welding in the atmosphere of the protective gases of the root of the weld, followed by manual stripping weld.

2. For the process of welding the vertical joint of two workpieces, additional labor-intensive operations are required to install the machine guide using tacks on one of the workpieces being welded. At the end of welding, the machine is removed and the guide must be dismantled.

The objective of the present invention is to provide a method and device for fusion welding by slot cutting, the use of which will allow vertical welding without preliminary mechanical processing of the edges of the parts to be welded and without preliminary manual welding of the root of the weld.

The technical result achieved to solve this problem is to improve the quality of welds along with the maximum cost-effectiveness of the welding process as a whole.

The specified technical result is achieved as a result of the application of the vertical fusion welding method along the slotted groove, in which the grooves are made the same in width along the entire length of the welded joint, regardless of the thickness of the parts to be welded using combs, a lead pocket and a lead plate that are pre-welded to the parts to be welded. Unlike the prototype, the parts to be welded are mounted in a vertical plane and, using a welding device, they weld in one pass from the bottom up to the consumable electrode in a mixture of protective gases, and the welding torch reciprocates from the forming slider to the forming lining, making stops in extreme positions, in which the initially moving distance produce vertical movement of the undercarriage with the welding head, while the control system of the welding device ystvom provides during welding automatic maintenance of total weld pool level with respect to the upper edge forming a slide.

The specified technical result is also achieved as a result of the use of a device for vertical fusion welding in a slotted groove in this method, which consists of a bogie on which a welding head is installed, which includes a welding torch, a welding wire feed mechanism, a protective gas supply unit, and a system management. In addition, the device contains vertical guides for moving the undercarriage, a reciprocating movement of the welding torch, and the device is equipped with a water-cooled forming lining for installation with wedges under the butt joints of the joints, and the welding head is equipped with a gas protection attachment with a forming water-cooled slider and its clamping mechanism .

The invention is illustrated by two graphic images (Fig. 1, 2). In FIG. 1 shows a butt joint with a slotted groove 10-12 mm wide, which is assembled from two parts 1 of the same thickness up to 100 mm using combs 4, an output pocket 2 and an output strip 3, welded to the parts 1. The output pocket and the output strip have a slot groove 10-12 mm wide and 50 mm long. Figure 2 shows the butt joint assembled for welding by slot cutting, installed in a vertical position on a stand at a height of 850-900 mm from the floor level.

The implementation of the present invention lies in the fact that the parts to be welded are assembled with a slotted groove, which should be the same (within 10-12 mm) in width along the entire length of the welded joint to be welded, and not depend on the thickness of the parts to be welded, which It is provided due to the use of combs, as well as a lead-out pocket and a lead-out strip welded to the parts. Then, the butt joint assembled for welding is installed in a vertical position on a stand at a height of 850-900 mm from the floor level and, using a welding device, automatic single-pass welding with a consumable electrode is performed using a gap groove in a mixture of protective gases with forced formation of a weld metal on both sides. In this case, the ratio between the width of the welded joint and the thickness of the parts decreases, which leads to an increase in the degree of contact hardening, i.e. to increase the strength of the welded joint. In addition, the cross-sectional area of the slit groove is reduced, therefore, the amount of deposited metal is reduced and the efficiency of the welding process as a whole increases. The technical result is achieved by performing the following sequence of operations:

- to the butt joint 5 to be welded, a welding device consisting of a movable platform 7 with a frame with vertical guides 8 mounted on it, along which the undercarriage 9 with a welding head having in its composition is rolled up and rigidly fastened with power clamps 6 the clamping mechanism 10 with a gas prefix 11 and forming a water-cooled slider 12, a torch 13 for welding into a slotted groove with a feed mechanism for the welding wire 14, the reciprocating mechanism of the torch 15 place with wire feed mechanism 14 and the cassette 16 with the welding wire;

- to the butt joint in the center of the slotted groove along its entire length from the side of the combs, using the wedges, a fixed water-cooled forming lining 17 is installed;

- using the control panel remote control, the welding head mechanisms are adjusted, i.e. a gas protection attachment 11 with a forming water-cooled slider 12 is installed in the center of the slotted groove and is pressed by a preload mechanism 10 to the surface of the butt joint, a torch 13 for welding into a slotted groove is installed in the center of the slotted groove with a reach of the welding wire equal to 25-30 mm with respect to the upper edge the forming slider 12, on the mechanism of reciprocating movement 15 of the burner 13, its stroke is set, the value of which is 10 mm less than the thickness of the welded product, while the burner 13 should not reach 5 mm to the surfaces of the forming slider and the forming lining;

- on the control panels of the welding device and the source of welding current, the parameters of the welding modes are set (moving speeds of the actuators of the welding device, welding current, arc voltage, etc.);

- when you press the "Start" button in the output pocket of the butt joint 5 with a slotted groove, the welding process begins: the torch 13 for welding into a slotted groove moves reciprocally from the forming slider 12 to the forming lining 17, making stops in the extreme positions in which initially defined distance (approximately 2.5 mm), the undercarriage 9 is vertically moved with the welding head, thus creating a common weld pool over the entire cross-sectional area of the slots oh cutting;

- when you press the "Stabilizer" button, the welding device starts to automatically maintain the level of the common weld pool relative to the upper edge of the forming slide 12 using a control system that controls the change in the stick-out of the welding wire by changing the magnitude of the welding current and, depending on this, regulating the amount of vertical movement undercarriage 9 with a welding head in the extreme positions of the welding torch 13, i.e. if the welding current increases during the welding process, the extension of the welding wire decreases and the level of the common weld pool approaches the upper edge of the forming slide 12, in this case, the control system of the welding device increments stepwise (0.1 mm step) the value of the originally set vertical movement of the undercarriage 9 with the welding head in the extreme positions of the welding torch 13 until the welding current drops to its original set value, thus the overall level of welding in relation to the upper edge of the forming slider 12 will reach its initial value, with a decrease in the welding current, the extension of the welding wire increases, and the overall level of the weld pool moves away from the upper edge of the forming slider 12, in this case, the control system of the welding device step-by-step decreases the value of the initially set vertical movement of the undercarriage 9 with the welding head in the extreme positions of the welding torch 13 until the welding current increases to its its initial set value, thus, the overall level of the weld pool with respect to the upper edge of the forming slider 12 will reach its original value;

- the welding process of the butt joint continues until welding of the slotted grooves in the lead-out strip, resulting in a shrinkage of welded parts that is uneven in thickness and the corresponding reduction in the cross-sectional area of the slotted grooves are monitored by the control system of the welding device, which accordingly changes the vertical movement of the undercarriage with the welding head in extreme positions of a special welding torch;

- after welding is completed, the welding device is disconnected and rolled back from the butt joint, the stationary forming lining is removed, the combs, the exit pocket and the lead-out strip are cut.

Claims (2)

1. A method of fusion welding of parts, including assembling parts, installing parts in an upright position and crevice welding, characterized in that the crevice is cut in the same width along the entire length of the welded joint by welding the combs, the output pocket and the lead-out strip to the parts to be welded, and welding is carried out in one pass from the bottom up by a consumable electrode in a mixture of shielding gases using a welding device comprising a running trolley, a welding torch and forming a water-cooled slider, and the forming lining, which is installed under the combs of the butt connection of parts by means of wedges, while the welding torch of the welding device is moved back and forth in the direction from the said forming slider to the forming lining with stops in extreme positions in which the running carriage is moved vertically by the initial distance the welding head of the welding device, while during the welding process maintain the level of the weld pool at the level of the upper pits forming a water-cooled slide. 2. A device for fusion welding of parts, comprising a bogie on which a welding head is installed, including a welding torch, a welding wire feed mechanism, a shielding gas supply unit and a welding mode control system, characterized in that it is provided with vertical guides for moving the bogie and the mechanism of the reciprocating movement of the welding torch, while the welding head is equipped with a gas protection attachment with a forming water-cooled slider and a mechanism for its clamping the surface of the welded components.

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