JPH0245550B2 - OOBAHETSUDOSABUMAAJIAAKUYOSETSUYOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an arc welding device. More specifically, the present invention relates to an apparatus for overhead submerged arc welding.

The invention can be applied to create circumferential welded joints in the longitudinal direction during the manufacture of articles from sheet materials of various thicknesses by welded joints.

<Prior Art> In manufacturing metallic structures, a large part of the work is spent welding essentially hollow parts with very limited access to the joints being welded from the inside. It is being healed. Such a joint is
Circular joints in closed vessels and housings such as those found in tank cars and boiler rooms, pipelines, field weld joints and slots in ship shells, flat sections that are difficult to turn over, etc. Generally includes circumferential connections.

Overhead submerged arc welding technology, compared to downward or flat welding, is characterized in that the weld pool is repeatedly pulled 180° with flux, the electrode is fed into the welding area upwardly or overhead, and The electrode is fed to the weld through a somewhat compressed flux.

This type of welding will therefore be referred to hereinafter as overhead submerged arc welding.

So-called overhead welds are therefore formed as a result of such welds.

In this type of welding, the arc burns through the thickness of the metal being welded.

During overhead welding of metal in a weld pool formed as a result of arc combustion caused by melting of the metal being welded, the electrode metal and flux form a skin or weld of partially molten flux. Prevented from flowing by the surface.

The flux is forced upwardly into the weld area and is continuously replenished as the flux is consumed.

To form the upper part of the weld, the flux is passed from below through the gap between the edges of the parts being welded together and from above in any suitable manner known in the art to form a bed of such flux. It is best to be supplied both with and without.

The main difficulty associated with overhead arc welding is that the weld pool must be maintained in a suspended state during the welding process, creating unstable welding conditions that complicate the formation of high quality welds. .

These problems are particularly prevalent when making welded joints on large-sized parts of articles having a cylindrical or similar shape, such as tank cars, boilers, and enclosed spaces in ship hulls. Such articles require very high quality welding and must be repeatedly pulled about their axis during the welding operation, or have substantial material that is difficult to repeatedly pull during the welding process. A planar area of
In other words, the flat part must be welded.

Overhead welding herein includes root welding and back-up welding.

The root weld is the one that is first made during welding of the butt joint and occupies the upper part of the welded joint on the side of the butt facing the direction of electrode feeding. However, the subsequent butt welding, or continuous welding, is accomplished by using any suitable known method of feeding the electrode from the same side as during the root overhead welding.

Overhead submerged arc welding of root welds allows for the elimination of welding operations on the inside of the tank while normally performing circular welds, and linear welds on structures where downward or flat welds are not possible. makes it possible to avoid the need to weld in closed spaces that are impossible to access when making parts.

Backup welds, on the other hand, are those that are initially created during welding of a butt joint and occupy the lower part of the weld on the side of the butt that is close to or facing the supplied electrode. be. Subsequent welding of the butt joints may be carried out by any suitable known method by applying an electrode on the side of the butt joint opposite the electrode required to perform the overhead weld. be exposed.

In practice, root welding techniques are used to make circumferential and longitudinal welds on articles and structures with internally limited access, while back-up welds are made from multiple segments, etc. It is made for joining butts of structures that are difficult to pull and repeat, such as sheet metal structures.

Backup welds present many problems associated with forming the finished weld surface. The quality of the weld surface largely depends on the correct selection of the selected value of the flux pressure and its continuous maintenance, in which the weld formation means and the compressed flux are transferred to the weld joint adjacent to the burning arc. It acts in many parts along the section, more specifically in the part immediately above the arc to the weld being formed, in the arc burning and weld pool area and in the part where the weld is being formed.

An electrode is fed to the joint to be welded through a container containing flux, the flux containing container welding a slide member and a weld tip extending through the slide member. Overhead submerged arc welding devices are known which are limited by a belt and whose elements are fixedly attached to the device (see USSR Inventor's Certificate No. 526470 IPC B23K9/18).

However, while performing overhead welds with this equipment, the flux and weld forming means are intended to apply a uniform pressure over a large portion of the length of the weld joint being made, so that the weld joint This results in an unstable sagging of the weld pool relative to the height of the part, resulting in disturbances during the welding process brought about by the formation of fissures in the welded joint.

Devices for overhead submerged arc welding are also known (USSR Inventor's Certificate No. 469554 IPC
(See B23K9/18, B23K37/06). An adjustment plate is placed inside the container, the position of which can be changed with respect to the surface of the object to be welded using adjustment screws.

Flux and electrodes are supplied from below the weld joint being made, and the pressure of the flux applied longitudinally of the weld joint being made is controlled by the use of control plates.

The operator maintains the trajectory of the welded joint being made during the operation of the device, so that problems such as the creation of gaps between the edges of the parts being welded are corrected as a result. In order to obtain high quality overhead welds when welding conditions deviate from the required conditions, it is necessary to accurately maintain a preselected pressure of the flux in multiple longitudinal sections of the joint. The operator ensures that the angle of inclination of the plate is adjusted to maintain the required pressure of the flux, as otherwise the welded joint would develop cracks and defects.

Therefore, the quality of the resulting weld is highly dependent on the skill and experience of the operator.

In view of the foregoing, although applicable for performing overhead route welds, the device is not adapted for overhead back-up welding. This is because experiment has shown that high quality back-up welds are at least difficult, if not impossible, to achieve through forming back-up welds exclusively by flux.

The welded connections made by the device are characterized by the presence of a plurality of cracks on the outside of the completed weld, which is characteristic for techniques that use fluxbeds to form back-up welds. These cracks have an undercut shape, local variations in the width of the weld, etc.

<Problems to be Solved by the Invention> Accordingly, the present invention provides a means for causing a flux hopper and the flux contained therein to interact with a weld being produced, and a method for bringing the hopper and flux into a weld area. By suitable structural arrangement of the pressing means, the overhead welding procedure can be automated to produce good overhead routes and back-up welds, and to obtain high quality weld connections, the welds being made can be It is an object of the present invention to provide an apparatus for overhead submerged arc welding that can create a predetermined pressure in many parts in the longitudinal direction of a joint part and ensure conditions for continuously maintaining it.

<Means for solving the problems> The object of the invention is to provide a flux hopper which is provided with a welding head containing flux and having a tip for a consumable electrode, and an object being welded in the area of the welding tip. In an apparatus for overhead submerged arc welding comprising means for supplying and pressing flux onto an object and means for forming a weld zone disposed near the welding tip, according to the present invention, the flux hopper is centered about its suspension axis. is rotatably mounted on the suspension part in order to be able to swing as a
Further, a welding part forming means and a follower element are disposed on the suspension shaft, and the welding device further includes means for swinging the flux hopper about the suspension shaft, and a welding device having a follower element. and means for pressing the object against the weld forming means.

The follower element and the welding part forming means are fixed on a suspension shaft of a flux hopper, and the welding part forming means and the follower are provided with another means for pressing the welding part forming means and the follower element against the object being welded. The above-mentioned structural arrangement of the proposed device, in which the flux hopper is provided with an element and means for swinging the flux hopper about its suspension axis, can be provided by the weld forming means and the follower element. makes it possible to independently adjust the amount of pressure possible,
The means for supplying and pressing the flux with that amount of pressure exerts a force towards the object being welded, which causes the weld to be formed without actually acting on the flux joint. The weld forming means is allowed to act directly to produce a high quality surface for the back-up weld.

Flux cushion in this specification is defined as uniformly distributed throughout the flux bed area;
and an area of compressed flux with pressure placed between the upper surface of the ball-shaped, i.e. bowl-shaped, casing and the surface of the object facing the object being welded; The cushion applies pressure to the surface of the weld joint being made in the weld area.

The suspension shaft of the flux hopper is arranged in a blanket provided with means for pressing a weld zone forming means having a follower element onto the object to be welded, and the pressure applying means is applied to the object to be welded. It is preferred to have a power drive source for moving the carriage towards the target.

A condition in which the above-mentioned device makes the surface of the object subject to the suspension axis of the flux hopper and the welding part forming means is that the flux given by a large number of longitudinal parts of the welded joint being made is It is possible to provide the conditions under which it is necessary to maintain each predetermined value of pressure stably during the welding process.

Preferably, said suspension axis is fixed to the flux hopper and is offset with respect to the means for supplying and pressing the flux onto the workpiece to be welded, so that the flux hopper suspended on this axis is attached to the two-arm lever. One arm of the two arms provides the means for supplying and pressing the flux onto the object, while the other arm itself is connected to means for swinging the flux hopper about its suspension axis. There is.

Such a configuration reduces the size of the device and allows it to be better responsive to surface irregularities of the objects being welded.

Preferably, the means for rocking the flux hopper about its suspension axis are constructed as a power drive rotatably connected to the flux hopper and the carriage.

The aforementioned arrangement of the means for swinging the flux hopper about its suspension axis causes a predetermined pressure value of the flux in the welding zone to be exerted on the workpiece by means of supplying and pressing the flux onto the workpiece. allows for easy adjustment.

The suspension part of the flux hopper rests on a moving chart which is made to be moved in the direction of the welding, and this makes it possible to create a longitudinal weld joint on a stationary or immovable object. Particularly advantageous.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now be described in detail with reference to various embodiments of the invention, which are illustrated in conjunction with the accompanying drawings.

An embodiment of the present invention for overhead submerged arc welding is shown in the accompanying drawings.

The apparatus 1 for arc welding comprises a hopper 1 containing a flux, i.e. a flux 2, in which the workpiece 3 to be welded is supplied with the flux 2.
Means for supplying and pressing is arranged. The means for supplying and pressing the flux 2 has a ball-shaped, ie bowl-shaped casing 4 that opens toward the object 4. This casing 4 communicates with a flux supply tube 5 having a screw conveyor 6 connected to a drive source 9 via a device consisting of bevel gears 7,8.

Flux is supplied from the flux hopper 1 to the joint being welded in the following manner.

Since the screw conveyor 6 is rotated by a driving source 9, the flux 2 passes through a plurality of inlets 10 made in the lower part of the flux supply tube 5 and passes along the supply tube 5 to the ball-shaped casing 4.
transported to.

The casing 4 provides a flux bed or cushion, thereby forming the completed weld 1.
The purpose is to apply local pressure to the longitudinally arranged part of the welded joint, which is made in front of the arc for 1. The flux hopper 1 is provided with a welding head 12 having a tip 13 for supplying a consumable electrode 14, which is supplied by means of an electrode supply mechanism 16 from a reel 15 of core wire. Welding tip 13
is arranged inside the flux hopper 1 to pass through the ball-shaped casing 4, while the end of the tip projecting towards the inside of the casing 4 is offset with respect to the flux supply tube 5.

The misalignment of the welding tip 3 with respect to the flux supply tube 5 causes the pressure of the flux 2 applied to the object 3 being welded to be unevenly distributed in the area where the flux is supplied from the hopper 1 to the ball-shaped casing 4. , on the other hand, is explained by the fact that in order to stabilize the welding conditions, the pressure of the flux 2 in the arc combustion zone in the vicinity of the electrode 14 needs to be uniformly distributed. Such a uniform distribution of flux pressure means that the flux cushion is pressed with a constant predetermined pressure on the object 3 and that this pressure distribution throughout the welding area is maintained during the relative movement of the object 3 and the welding device. This is achieved by being ensured by the resulting frictional force.

At the same time, the excess flux that fails to be consumed by the welding process tends to flow past the ball-shaped casing 4 and fall freely into the flux hopper 1. This ensures reuse or circulation of the flux 2 from the hopper 1 to the welding area, which makes the welding procedure more economical.

The welding part forming means 17 is a ball-shaped casing 14
It is provided at a position a certain distance from the electrode 4 and close to the welding tip 13 on the inner side.

The weld forming means 17 are generally made of a thermally conductive material and are mutually bonded to the flux cushion and the object 3 in order to create the necessary pressure in the weld area and to form the completed weld 11. It is a flat plate with a working surface shape. This flat plate 17 is preferably cooled by air or water.

In order to obtain high quality back-up welds, the weld forming means 17 can be made as a slide and made for direct contact with the weld being formed. This results in better quality of the finished weld 11.

According to one feature of the invention, the flux hopper is suspended for rocking about a suspension axis 18. The suspension shaft 18 of the hopper 1 can be fixed either on the hopper 1 itself or on the ball-shaped casing 4 and must be offset relative to the electrode 14 towards the completed weld 11.

The suspension axis 18 of the flux hopper 1 must provide a swinging movement of the hopper 1 in the plane of the weld joint being made.

On the suspension shaft 18 of the hopper 1 rests the weld forming means 17, which can also carry out an oscillating movement in the plane of the weld joint being made, thereby Therefore, it is self-aligned with the surface of the object 3.

Further, on the suspension shaft 18 of the flux hopper 1, a follower element 19 in the form of a wheel, for example, is mounted. The purpose of the follower element 19 is to provide a constant distance between the surface of the object 3 and the suspension axis 18 of the hopper 1 .

This continuity within said distance is necessary to stabilize the pressure values that can be exerted by the flux cushion on the surface of the object 3, whereby all welding factors are stabilized. be done. In order to provide the necessary pressure that can be exerted by the flux cushion on the object 3, the device comprises a device for rocking the flux hopper 1 about its suspension axis 18, a weld forming means 17 and a follower. means for pressing the element 19 onto the object 3.

The suspension shaft 18 of the flux hopper 1 is arranged on a bracket 20 fixed on a carriage 21. The carriage 21 is made to move in the direction towards the object 3 and is arranged for that purpose on a plurality of guides, such as guide rods 22. The carriage 21 includes means for forming a weld 17 and means for pressing the follower element 19 onto the object 3;
The means are in the form of a power drive source 23, such as a pneumatic or hydraulic cylinder, which serves to move the carriage 21 towards the object 3.

The suspension shaft 18 is fixed on the flux hopper 1 (or on the ball-shaped casing 4 that is made integrally with the flux hopper 1), and the hopper 1 suspended on the suspension shaft 18 has two arm levers. In addition, the suspension shaft 18 is displaced relative to the means for supplying and pressing the flux 2 onto the object 3.
Preferably, one arm of this lever accommodates means for supplying and pressing the flux 2 onto the object 3, said means comprising said plurality of elements.

It is further advantageous if the other arm of the two arms is connected to means for swinging the flux hopper 1 about its suspension axis 18. The means for rocking the flux hopper 1 about its suspension axis is provided as a power drive source 24 (such as an air or hydraulic cylinder) pivotally connected to the flux hopper 1 and the carriage 21. The power drive source 24 may be suitably designed in other ways, for example it may have the form of a spring means or it may be made like a weight attached to the flux hopper 1.

The device of the flux hopper 1, in the form of a two-arm lever, provides a highly sensitive system capable of adapting to the surface irregularities of the workpiece 3 being welded and exerting the required pressure in the welding area. maintained automatically.

When necessary, the device can be moved in the welding direction. For this purpose, a mobile cart 25 is provided, on which a carriage 21 is mounted.
A guide rod 22 for movement of the carriage 21 is fixedly mounted and a power drive means 23 is rotatably mounted for imparting movement to the carriage 21.

This cart 25 is necessary for the movement of the device in the longitudinal direction of the welding joint being made. The cart 25 is therefore able to move the entire device along the weld joint, which
Particularly when performing overhead welding, it is often necessary to weld substantially flat or plate-like objects that are difficult to pull back.

The advantages of the device are said to be particularly advantageous during overhead back-up welding.

The overhead submerged arc welding device operates as follows.

Before starting the welding operation, Flux 2
It can be placed in Hoppa 1. Flux used 2
The components of are usually selected depending on the objects to be welded, the geometry of the weld joint and the optimum welding conditions. The flux used is generally silicon,
Consisting of manganese, sulfur and ingredients to ensure stable arc combustion, melting of the objects to be welded, protection of the weld pool and formation of a finished weld joint.

Prior to starting the welding operation, the device is first moved below the object to be welded. At that time 2
Two methods are possible. For example, when welding a long rectangular joint of a large object,
It is common for the equipment to be moved in the longitudinal direction of the weld, whereas when welding rotatable structures the equipment remains stationary so that the joint being made maintains its position within the electrode combustion zone. The object is rotated about its own axis so as to maintain its position.

Thereafter, the power drive source 23 of the carriage 21 adjusted for welding the workpiece is started, and the drive source 23 is operated by means of the carriage 21 placed on the guide rod 22, the bracket 20 and the suspension shaft 18. , such a pressing force of the weld forming means 17 acts to press the weld forming means 17 against the object 3 to be welded, such that the follower element (such as a follower wheel) It is maintained until it comes into contact with.

The driving source 24 of the flux hopper 1 is a pivot 26
is engaged and adjusted to act on the flux hopper 1 via the hopper 1 in order to weld the particular type of object 3 being welded. At the same time, by swinging the hopper 1 about its suspension axis 18, the ball-shaped casing 4 is pressed against the outer surface of the object 3.

Then, bevel gears 7, 8 are placed on the screw conveyor 6.
The drive source 9 is energized so that the flux 2 passes through the plurality of inlets 1
0 and is conveyed along the flux supply tube 5 to the ball-shaped casing 4. The flux 2 supplied to the casing 4 acts to produce a flux cushion on the surface of the weld joint being made.

Drive source 27 of cart 25 is then engaged.
(This is done in particular for welding longitudinal joints, and in order to compress the circumferential joints somewhat, the drive source 27 is not engaged and the object, not shown in the accompanying drawings) (means for rotating is actuated.)
Voltage is then applied to electrode 14 and electrode delivery mechanism 16 of weld head 12 is engaged to feed electrode 14 from core wire reel 15 through weld tip 13 to the weld joint. Welding is thereby carried out in such a way as to produce a completed weld 11.

The accompanying drawings illustrate a welding operation for forming a circular weld with the welding device in a stationary position and the object being rotated. During the rotation of the object, the follower element 19 cooperates with the surface of the object. Irregularities in the surface of the object 3 cause the follower elements to adapt to the shape of the object 3 and act on the bracket 20 in response to variations in this shape, while at the same time adjusting the position of the weld forming means relative to the surface of the object. Set.
The continuous pressure of the follower element 19 and the welding part forming means 17 is provided on the surface of the object 3 to be welded by the power drive source 23 of the carriage 21.

The arrangement of the weld forming means 17 on the suspension axis of the hopper enables the hopper to follow the surface of the object 3, while positioning the weld forming means 17 and the follower element on one axis allows the weld to It is ensured that a constant distance is maintained between the forming means 17 and the surface of the object 3 to be welded. This also ensures a constant pressure of the flux in the welding area. At the same time, a layer of flux 2 can be formed between the weld forming means 17 and the surface of the weld joint being made, in which case the pressure is applied through this layer of flux to the weld. Added above the joint. Such welding conditions are necessary to perform overhead backup welding.

Alternatively, no flux layer may be provided between the weld forming means 17 and the surface of the weld joint being made. In this case, the weld forming means 17 are in direct contact with the joint, thereby applying the necessary pressure to the joint.
In such a contact between the weld forming means 17 and the weld joint being made, the completed weld 1
Conditions for better surface performance of 1 are ensured. Completed weld part 1 in such a case
1 has a precisely defined geometrical shape and a joint 1
1 to the base metal of the object 3, the weld in this case is good in external appearance and has a smooth external surface.

These welding conditions are typically used to create backup welds that do not require post-weld processing.

Apart from this, the weld-forming means 17 are in direct contact with the weld joint to be made, while the weld-forming means 1
Other welding conditions are also possible, such that the contact between 7 and the surface of the object 3 takes place via a flux cushion.

These welding conditions apply to objects with substantial variations in values and parameters relative to the material before being welded, such as excessive edges, gaps, etc.
It is generally preferred for performing overhead backup welds on objects that have local irregularities in the surface of the weld joint, such as single or continuous waves, depressions, etc.

Therefore, there is a possibility of separate adjustment of the arrangement of the welding part forming means 17 and the follower element 19 on the suspension axis of the flux hopper 1 and of the force with which the welding part forming means 17 and the flux cushion are pressed against the object 4. allows overhead submerged welding operations to be automated, thus practically avoiding operator interference. Another advantage is that the proposed device produces high quality welds, especially high quality overhead backups.

[Brief explanation of the drawing]

The accompanying drawing is a longitudinal sectional view of a device for overhead submerged arc welding according to the invention. 1...Flux hopper, 2...Flux,
3...Object being welded, 4...Ball-shaped casing, 5...Flux supply tube, 6
... Screw conveyor, 7, 8 ... Bevel gear, 9
... Screw conveyor drive source, 10 ... Inlet in flux supply tube, 11 ... Completed welding section, 12 ... Welding head, 13 ... Welding tip, 14 ... Electrode, 15 ... Core wire reel, 16... electrode supply mechanism, 17... welding forming means, 18... suspension shaft of flux hopper, 19...
... Follower element, 20 ... Bracket, 21 ... Carriage, 22 ... Guide rod, 23 ... Carriage drive source, 24 ... Flux hopper drive source, 25 ... Moving cart, 26 ... Pivot, 27 ...
...The driving source of the cart.

Claims (1)

[Scope of Claims] 1. A hopper 1 provided with a welding head 12 with a tip 13 for an electrode 14 that contains flux 2 and is expendable, and an object being welded in the area of the welding tip 13. In the apparatus for overhead submerged arc welding, which comprises means for supplying and pressing the flux 2 onto the object 3 and a weld forming means 17 disposed near the welding tip 13, the flux hopper 1 has its suspension shaft 18 The welding part forming means 1 is rotatably fixed to the suspension part so as to be swingable about the center, and furthermore, the welding part forming means 1 is mounted on the suspension shaft 18.
7 and a follower element 19 are placed thereon, furthermore, means for swinging the flux hopper 1 about its suspension shaft 18, and the welding part forming means 17 having the follower element 19 are welded to the object. 3. An apparatus for overhead submerged arc welding, characterized in that it has means for pressing against the welding material. 2. The suspension shaft 18 of the flux hopper 1 is arranged on a bracket 20 provided with means for pressing the welding part forming means 17 provided with the follower element 19 against the object 3 being welded, and this pressing is applied. a power drive source 23 for moving the carriage 21 towards the object 23 to which the means are being welded;
The apparatus according to claim 1, characterized in that it has the following system. 3 The suspension shaft 18 is fixed so as to be offset from the means for supplying and pressing the flux 2 to the object 3 being welded, so that the flux hopper 1 suspended on this suspension shaft 18 is welded. one arm that accommodates a means for supplying and pressing the flux 2 onto the object 3, and its suspension shaft 18;
The device according to claim 1 or 2, characterized in that the device acts as a two-arm lever, comprising another arm connected to a means for swinging the flux hopper 1 about the center. 4 A power drive source 2 whose means for swinging the flux hopper 1 about its suspension shaft 18 is rotatably connected to the flux hopper 1 and the carriage 21.
4. Device according to claim 3, characterized in that the device is made as 4. 5. Any one of claims 1 to 4, characterized in that the suspension part of the flux hopper 1 is placed on a moving cart 25 that is made to move in the welding direction. The device described in.