JP7088748B2 - Welding equipment and welding method - Google Patents

Description

The present invention relates to a welding device and a welding method.

In a welded structure, welding deformation occurs due to the heat applied during welding. Weld deformation leads to deterioration of assembly accuracy of members. For this reason, a step of correcting deformation such as burning with a burner or the like after welding or pressing with a press is required. The process of correcting such welding deformation has contributed to the decrease in construction efficiency of the entire welding process.

Patent Document 1 discloses a welding device that removes a surplus after welding by an end mill.

Japanese Unexamined Patent Publication No. 11-285829

In order to improve the efficiency of the welding process, there is a demand for welding equipment and welding methods that reduce welding deformation that occurs during welding.

Therefore, an object of the present invention is to provide a welding device and a welding method for reducing welding deformation.

The welding apparatus according to the embodiment of the present invention includes a welded portion that melts the weld wire and the base metal to be welded by an arc, and a removing mechanism that partially removes the molten metal melted in the welded portion. The removing mechanism has a scraping portion for scraping out the molten metal and a reservoir for storing the molten metal scraped by the scraping portion .

According to the embodiment of the present invention, it is possible to provide a welding device and a welding method for reducing welding deformation.

It is a perspective view which shows the use state of the welding apparatus which concerns on one Example. It is a schematic cross-sectional view which shows the use state of the welding apparatus which concerns on one Example. It is a top view which shows the shape of a molten pool. It is a schematic cross-sectional view which shows the use state of the welding apparatus which concerns on a reference example. It is a figure explaining by contrasting the simulation result of welding deformation. It is sectional drawing which compares the crystal structure of the bead which contrasts one Example with a reference example. It is a perspective view which shows the use state of the welding apparatus which concerns on other Examples. It is a perspective view which shows the use state of the welding apparatus which concerns on still another Example.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate explanations may be omitted.

The welding apparatus 1 according to one embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing a usage state of the welding apparatus 1 according to one embodiment.

The welding device 1 includes a welding torch 3 to which the welding wire 2 is fed, and a surplus removing mechanism 4. Further, in the example of FIG. 1, an example of welding two base materials 5 with a butt joint is shown.

Further, the welding device 1 includes a welding power supply (not shown) and a wire feeding device (not shown). The welding power supply is a power supply for generating an arc 6 (see FIG. 2 described later) between the welding wire 2 and the base metal 5, one electrode is connected to the base metal 5, and the other electrode is a welding torch. 3 is connected to a contact chip (not shown). The wire feeding device is a device that automatically feeds the welding wire 2 to the welding torch 3.

The welding torch 3 includes a contact tip (not shown). The contact tip guides the welding wire 2 fed from the wire feeding device and supplies the welding current from the welding power source to the welding wire 2.

The moving direction F3 of the welding torch 3 is indicated by an arrow. The welding torch 3 moves on the portion where the two base materials 5 meet. The welding current supplied from the welding power source generates an arc 6 (see FIG. 2 described later) between the welding wire 2 and the base metal 5. At this time, the high heat generated by the arc 6 melts the welding wire 2 and becomes droplets to move to the base material 5. In addition, a part of the base material 5 is also melted. The molten welding wire 2 and the base metal 5 form a molten pool 7 as a molten metal. Then, the molten metal of the molten pool 7 is cooled and solidified to form a bead 8, and the two base materials 5 are welded together.

The welding device 1 of this embodiment includes gas metal arc welding (GMAW: Gas Metal Arc Welding), submerged arc welding (SAW: Submerged Arc Welding), flux-filled wire arc welding (FCAW: Flux Cored Arc Welding), and the like. It can be a welding device that uses arc welding.

When the welding device 1 is a welding device that performs gas metal arc welding, the welding device 1 includes a shield gas supply device (not shown). The shield gas supply device is a device that supplies a shield gas such as carbon dioxide gas and argon gas to the welding torch 3. The supplied shield gas is ejected from a nozzle (not shown) of the welding torch 3 and covers the arc 6 and the molten metal during welding to prevent air from entering the welding atmosphere.

Further, when the welding device 1 is a welding device that performs submerged arc welding, the welding device 1 includes a flux supply device (not shown). The flux supply device supplies flux to the surface of the base metal 5 on the front side of the welding torch 3 with reference to the moving direction F3.

Further, when the welding device 1 is a welding device that performs wire arc welding containing flux, the welding wire 2 has a hollow structure, and the inside is filled with flux or the like.

The surplus filling removing mechanism 4 has a function of removing a part of the molten metal (surplus filling portion of the bead 8) from the molten pool 7. The surplus removal mechanism 4 is arranged on the rear side of the welding torch 3 with reference to the moving direction F3. The moving direction F4 of the surplus removing mechanism 4 is indicated by an arrow. The surplus removal mechanism 4 follows the welding torch 3 and moves in the same direction. When the welding torch 3 is an automatic welding device that is moved by a manipulator, the surplus removal mechanism 4 may also be attached to the same manipulator as the welding torch 3. Further, the welding torch 3 and the excess filling removing mechanism 4 may be attached to independent manipulators.

Next, the surplus removal mechanism 4 will be further described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing a usage state of the welding apparatus 1 according to the first embodiment. In FIG. 2, the welding torch 3 is not shown. Further, the height of the surface of the base metal 5 is shown by a broken line 5a.

The surplus removing mechanism 4 according to the first embodiment is formed as a substantially L-shaped scraper in a cross-sectional view. The surplus removing mechanism 4 slides on the surface of the base material 5 or slightly rises and moves from the surface of the base material 5 to scrape a part of the molten metal from the molten pool 7 and to scrape a part of the molten metal from the bead 8. Reduce excess filling.

The surplus removing mechanism 4 has a scraping portion 41 and a reservoir portion 42.

The scraping portion 41 is a portion for scraping the molten metal from the molten pool 7. The scraped portion 41 is formed in a wedge shape with a flat lower side (side of the molten pool 7) and a taper on the upper side (opposite side of the molten pool 7). As shown in the scraping direction F9, a part of the molten metal of the molten pool 7, specifically, a portion raised above the surface of the base metal 5 is scraped out by the scraping portion 41. The scraped molten metal 9 rides on the surplus removing mechanism 4 along the taper of the scraped portion 41 and moves to the reservoir portion 42.

The reservoir 42 is a portion for storing the scraped molten metal 9 so as not to return to the molten pool 7 again. The surplus removing mechanism 4 shown in FIG. 2 is configured so that the molten metal 9 scraped out by the scraping portion 41 does not return to the molten pool 7 again by the member standing up on the rear side in the moving direction F4.

The molten metal 9 in the reservoir 42 is discharged from the reservoir 42 at a predetermined timing (for example, after the completion of welding) after solidification. The discharging method is not limited to this, and the molten metal 9 of the reservoir 42 is discharged in the vertical direction of the paper surface (longitudinal direction of the surplus removing mechanism 4 in FIG. 1) in FIG. You may.

Further, it is preferable that the surplus removing mechanism 4 has heat resistance above the melting temperature of iron and is made of a non-conductive material. Specifically, ceramic can be used as the material of the surplus removal mechanism 4. Since the excess filling removing mechanism 4 has heat resistance, it is possible to prevent deformation due to heat. Since the surplus removing mechanism 4 is made of a non-conductive material, it is possible to prevent electric discharge between the welding wire 2 and the surplus removing mechanism 4, and between the welding wire 2 and the base material 5. The arc 6 can be generated.

Although the surplus removing mechanism 4 has been described as being formed as a scraper, the structure is not limited to this, and any other structure can be used as long as it can scrape a part of the molten metal from the molten pool 7. There may be. For example, it may be configured as a roller having a scraping portion for scraping a part of the molten metal.

FIG. 3 is a top view showing the shape of the molten pool 7.

As shown in FIG. 3, the arc 6 melts the metal of the base metal 5 to form the recess 10. Then, the molten pool 7 is formed on the rear side of the welding torch 3 in the traveling direction. Here, when viewed from above, the length L in the traveling direction from the center of the welding wire 2 to the rear end of the molten pool 7 is a welding speed of 30 cm / min in MAG welding, and is approximately 5 mm or more and 15 mm under various welding conditions. It is as follows. Therefore, it is preferable to provide the tip of the scraped portion 41 of the surplus removing mechanism 4 at a position within 5 mm in a horizontal distance from the center of the welding wire 2. Further, as shown in FIG. 2, it is preferable that the rear end of the surplus removing mechanism 4 fits within the range of the molten pool 7. With this configuration, the molten metal has not yet solidified when the surplus removing mechanism 4 has passed and a part of the molten metal has been scraped out, and the molten metal has solidified after the surplus removing mechanism 4 has passed. The bead 8 can be formed.

Here, the welding apparatus 1X according to the reference example will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view showing a usage state of the welding apparatus 1X according to the reference example. The welding device 1X according to the reference example is different from the welding device 1 shown in FIGS. 1 and 2 in that it does not have the surplus removing mechanism 4. Other configurations are the same, and duplicate description will be omitted.

Due to the high heat generated by the arc 6, the welding wire 2 melts and becomes droplets, which move to the side of the base metal 5. In addition, a part of the base material 5 is also melted. The molten welding wire 2 and the base metal 5 form a molten pool 7X as a molten metal. Since the welding wire 2 is transferred to droplets, the molten pool 7X is formed so as to rise above the surface of the base metal 5. Then, the molten metal of the molten pool 7X is cooled and solidified to form the bead 8X. The bead 8X forms an extra ridge that is raised above the surface of the base metal 5.

The welding device 1 according to the first embodiment and the welding device 1X according to the reference example will be described in comparison with each other. 5A and 5B are diagrams for comparing and explaining the simulation results of welding deformation, FIG. 5A is a simulation result when arc welding is performed by the welding apparatus 1 according to one embodiment, and FIG. 5B is a welding according to a reference example. The simulation result at the time of arc welding by the apparatus 1X is shown. The upper part shows the cross-sectional shape of the base metal and the bead used in the simulation, the middle part shows the enlarged view of the bead, and the lower part shows the simulation result of welding deformation. The simulation results are shown so that the larger the amount of deformation of the base material 5 in the plate thickness direction, the darker the color.

Weld deformation occurs due to expansion and contraction of molten metal that is melted and solidified during welding. When welded by the welding device 1X shown in FIG. 4, the surplus portion of the bead 8X also shrinks. Therefore, as shown in FIG. 5B, in the welding deformation of the base metal 5, the surface of the base metal 5 is deformed in the negative direction, the amount of deformation is large, and the width direction from the periphery of the bead 8X (short of the bead 8X). It is widespread over (hand direction).

On the other hand, in the welding apparatus 1 shown in FIG. 2, a part (surplus) of the molten metal is scraped out from the molten pool 7 by the surplus removing mechanism 4 before the molten metal in the molten pool 7 solidifies. .. As a result, in the welding device 1 according to one embodiment, the amount of molten metal solidified during welding can be reduced as compared with the welding device 1X according to the reference example. Therefore, as shown in FIG. 5A, the welding deformation of the base metal 5 when welded by the welding device 1 has a small amount of deformation and a narrow range.

Therefore, it is possible to reduce the welding deformation in the bead 8 in which the surplus is removed as shown in FIG. 5 (a), as compared with the welding deformation in the bead 8X with the surplus shown in FIG. 5 (b).

Next, the cross-sectional shape of the bead 8 in one embodiment is compared with the cross-sectional shape of the bead 8X2 obtained by cutting the surplus portion of the bead 8X in the reference example. 6A and 6B are views for explaining the cross-sectional shape of the bead in comparison with each other, where FIG. 6A is a schematic view of the cross-sectional shape of the bead 8 in one embodiment, and FIG. 6B is a surface layer of the bead 8 in one embodiment. A schematic cross-sectional view showing a microstructure, (c) is a schematic cross-sectional shape of the bead 8X2 in the reference example, and (d) is a schematic cross-sectional view showing the microstructure of the surface layer of the bead 8X2 in the reference example.

The molten metal melted by the arc solidifies from the side of the base metal 5. Therefore, as shown in FIG. 6A, the final solidified portion tip 81 of the molten metal is formed substantially in the center of the surface of the bead 8. Further, when the molten metal solidifies, it solidifies from the side of the base metal 5 toward the tip 81 of the final solidified portion, so that a line pattern 82 is formed by the solidified weld metal. Therefore, the line pattern 82 is formed so as to extend and converge to the tip 81 of the final solidified portion substantially at the center of the surface of the bead 8.

Even in the bead 8X with a surplus, the tip of the final solidified portion is formed substantially in the center of the surface of the bead 8X, and a line pattern by the solidified weld metal is formed from the side of the base metal 5 toward the tip of the final solidified portion. Then, in the cross-sectional shape of the bead 8X2 obtained by cutting (or grinding) the surplus portion, as shown in FIG. 6C, the tip of the final solidified portion disappears by cutting, and the line pattern 82 is the bead 8X2. It is not formed to converge toward a point on the surface after cutting.

As described above, the cross-sectional state of the bead 8 welded by the welding device 1 according to the first embodiment and the cross-sectional state of the bead 8X2 welded by the welding device 1X according to the reference example and the surplus is cut are the lines. The composition of the pattern 82 is different.

Further, as shown in FIG. 6B, the microstructure of 83 near the surface of the bead 8 remains as it was when the surface of the bead 8 was not cut and solidified, so that the grain boundaries and the bead surface coincide with each other. It is formed to do.

On the other hand, in the microstructure of 83X near the surface of the bead 8X2, as shown in FIG. 6D, since the surface of the bead 8X2 is cut, there are places where the grain boundaries and the bead surface do not match. ..

As described above, the cross-sectional state of the bead 8 welded by the welding device 1 according to the first embodiment and the cross-sectional state of the bead 8X2 welded by the welding device 1X according to the reference example and the surplus is cut are the beads. The composition is also different in the microstructure near the surface of.

Further, the corrosion that erodes along the grain boundaries is stronger in the microstructure of FIG. 6B than in the microstructure of FIG. 6D.

As described above, according to the welding apparatus 1 according to the embodiment, the molten metal before solidification can be reduced by removing a part of the molten metal from the molten pool 7 by the surplus removing mechanism 4. This makes it possible to reduce welding deformation caused by expansion and solidification of the molten metal.

Further, as a conventional method for reducing welding deformation, a welding method that reduces heat input during welding is being developed. However, in the welding method with reduced welding heat input, the amount of weld metal that can be welded to the welded portion in one pass decreases as the welding heat input decreases, leading to an increase in the number of welding passes and construction efficiency. There is a problem that On the other hand, according to the welding apparatus 1 according to the embodiment, the welding deformation can be reduced without reducing the heat input, so that it is possible to prevent the construction efficiency from being lowered.

Further, as a conventional method for reducing welding deformation, a welding material for reducing welding deformation is being developed. However, a welding material that reduces welding deformation requires a special material, which has a problem of increasing the cost. On the other hand, according to the welding apparatus 1 according to the embodiment, the welding materials such as the welding wire 2, the shield gas, and the flux can be the same as those of the conventional welding apparatus, so that a special material is required. However, it is possible to prevent an increase in cost.

Further, according to the welding device 1 according to the embodiment, since it can be configured by adding the surplus removing mechanism 4 to the conventional welding device, the device can be configured without excessively increasing the device cost. Can be done.

FIG. 7 is a perspective view showing a usage state of the welding apparatus 1A according to another embodiment. The welding device 1A has a different configuration of the surplus removing mechanism 4A as compared with the welding device 1. Other configurations are the same, and duplicate description will be omitted.

The surplus removing mechanism 4A is arranged at a position behind the welding torch 3 with respect to the moving direction F3 and deviated in the width direction (the direction orthogonal to the vertical direction and orthogonal to the moving direction F3). As a result, the surplus removing mechanism 4A is arranged at a position that does not cover the molten pool 7 and the bead 8. The moving direction F4A of the surplus removing mechanism 4A is indicated by an arrow. The surplus removal mechanism 4A follows the welding torch 3 and moves in parallel.

The surplus removing mechanism 4A includes a nozzle 45 that injects the gas G in the width direction. By injecting the gas G from the nozzle 45, a part (surplus) of the molten metal is blown off from the molten pool 7 and removed. As the gas G, it is preferable to use a shield gas such as carbon dioxide gas or argon gas.

According to the welding apparatus 1A according to another embodiment, welding deformation can be reduced as in the welding apparatus 1 according to one embodiment. In addition, it is possible to prevent a decrease in construction efficiency. In addition, no special material is required, and cost increase can be prevented. In addition, the device can be configured without excessively increasing the device cost.

Further, according to the welding apparatus 1A according to another embodiment, since the surplus removing mechanism 4A can be configured without passing over the molten pool 7, the degree of freedom of installation can be improved.

Further, according to the surplus removing mechanism 4A of the welding apparatus 1A according to another embodiment, the removed molten metal can be blown off, so that the surplus removing mechanism 4 for removing the metal scraped from the reservoir 42 is compared with the surplus removing mechanism 4. , Continuous use is possible.

FIG. 8 is a perspective view showing a usage state of the welding apparatus 1B according to still another embodiment. The welding device 1B has a different configuration of the surplus removing mechanism 4B as compared with the welding device 1. Other configurations are the same, and duplicate description will be omitted.

The surplus removal mechanism 4B is integrally formed with the welding torch 3.

According to the welding apparatus 1B according to another embodiment, welding deformation can be reduced as in the welding apparatus 1 according to one embodiment. In addition, it is possible to prevent a decrease in construction efficiency. In addition, no special material is required, and cost increase can be prevented. In addition, the device can be configured without excessively increasing the device cost.

Further, according to the surplus removing mechanism 4B of the welding apparatus 1B according to another embodiment, the surplus removing mechanism 4B can be moved together with the welding torch 3. Thereby, for example, when the welding torch 3 is an automatic welding device moved by a manipulator, the device can be configured without adding a manipulator.

The preferred embodiment of the present invention has been described in detail above. However, the invention is not limited to the embodiments described above. Various modifications, substitutions, etc. can be applied to the above-described embodiments without departing from the scope of the present invention. Also, the features described separately can be combined as long as there is no technical conflict.

1,1A, 1B Welding device 2 Welding wire (welding target)
3 Welding torch (welded part)
4,4A, 4B Excess removal mechanism (removal mechanism)
5 Base material (welded target)
6 Arc 7 Molten pond 8 Bead 81 Final solidification part Tip 9 (scraped) molten metal 10 Depression 41 Scraping part 42 Reservoir 45 Nozzle F3, F4 Moving direction F9 Scraping direction G gas

Claims (5)

Welded parts that melt the weld wire and base metal to be welded by arc,
A removal mechanism for removing a part from the molten metal melted in the welded portion is provided .
The removal mechanism is
A scraping portion that scrapes out the molten metal and
It has a reservoir for storing the molten metal scraped by the scraped portion.
Welding equipment. The removal mechanism is
The welding apparatus according to claim 1, wherein when the molten metal is solidified to form a bead, the portion corresponding to the surplus portion, which is a portion that rises above the surface of the base metal, is removed from the molten metal. The welding apparatus according to claim 1 or 2, wherein the scraping portion is a scraper that scrapes out the molten metal. The reservoir is configured so that the member stands up on the rear side in the moving direction.
The welding apparatus according to claim 1 or 2. A step of melting the welding wire and the base metal by an arc generated between the welding wire and the base metal to form a molten metal reservoir.
It has a step of scraping a part of the molten metal from the molten metal by a removing mechanism and storing the scraped metal so as not to return to the molten metal to remove a part of the molten metal . Welding method.

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