JPS6320474Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) This invention is applicable when overlaying stainless steel, etc. on the inner surface of a thick-walled pressure vessel, or when overlaying stainless steel, etc. on a mild steel slab material during overlay welding of stainless steel, etc. to a mild steel slab material when manufacturing overlay rolled crud steel. This invention relates to a horizontal electroslag strip electrode overlay welding device. (Conventional technology) Horizontal electroslag strip electrode build-up welding method is
For example, it is known from various publications such as ``Dissimilar metal welding method using horizontal electroslag welding method'' (Japanese Patent Application Laid-open No. 17349/1983). Before the horizontal electroslag strip electrode build-up welding method was used, a strip electrode build-up welding method using a submerged arc method was used. The horizontal electroslag method and the submerged arc method can be welded using exactly the same welding machine and are very similar, but as shown in Figure 1a, the horizontal electroslag method uses a strip electrode All of the flux 1 spread behind the electrode 2 (except for both ends of the electrode 2) is melted by the joule heat and becomes molten slag 3. However, in the submerged arc method shown in Figure 1b, the arc 4 is covered with flux 1. This point is very different. In other words, in the strip electrode overlay welding method using the horizontal electroslag method, the flux must be spread in just the right amount.
Arcing occurs, and the horizontal electroslag method is no longer possible. Excessive dispersion also results in unmelted flux and unwelded areas of overlay metal due to insufficient heat. As described above, in the horizontal electroslag strip electrode overlay welding method, one of the tricks of the welding operator is to perform welding while keeping the height of the scattered flux constant. However, since this welding method is an automatic welding method, it is necessary to devise a method that allows welding without relying on the attention of the welding operator as much as possible. Publication No. 58-128787)
This method adjusts the amount of sprinkled flux that flows into the molten slag from both ends of the strip electrode, and the height of the flux that gradually accumulates in front of the electrode during welding is adjusted. is not kept constant. (Technical background of the invention) In view of such human considerations, the inventors of the present invention, when performing horizontal electroslag strip electrode overlay welding,
After considering how to perform stable welding without relying on the attention of the welding operator, we found that in addition to the selection of flux and the adoption of magnetic control, the success of this welding method requires a flux distributor and a strip It has been found that it is important to automatically remove the flux that accumulates between the electrode and the electrode. In particular, as the width of the strip electrode increases from the conventional 75 mm to 150 mm or 300 mm, even a slight difference in the height of the sprayed flux will have an effect. As shown in FIG. 2, the strip electrode 2 itself is curved concavely with respect to the welding direction W to prevent buckling, and the unmelted flux 1 ends up in the center of the electrode 2. They come together. As mentioned above, the welding of strip electrodes used to be done using the submerged arc method, but in order to widen the electrodes and increase efficiency, the process shifted to the horizontal electroslag method, which requires welding machines or magnetic control. Currently, the method is the submerged arc method, but the flux component (which increases the electrical conductivity of the molten slag) is changed, and the horizontal electroslag method is used. However, as shown in Figure 1, in the horizontal electroslag method, all of the flux in front of the electrode must be melted and the molten slag behind the electrode must be kept exposed, resulting in a submerged arc. Different from the method. Currently, no countermeasures have been considered for the horizontal electroslag method to deal with such phenomena that exhibit different states. In addition, the flux used in the submerged arc method is mainly a bonded flux type, which has a low bulk density and is light, so even if there is a little more scattered flux and it is deposited in front of the electrode, there is no problem, and the deposited flux is On the contrary, it would be advantageous if it were to wrap around from both ends of the electrode to cover the rear of the electrode. On the other hand, in the horizontal electroslag method, bond flux with a large gas component tends to cause arcing, so molten flux is mainly used. Although it depends on the flux particle size, the molten flux has a large bulk density and is heavy, and the flux that is not melted by the flux sprinkled during welding is difficult to escape toward both ends of the electrode and is deposited in front of the electrode. In this case, since the strip electrode has a thin wall of about 0.4 mm, it will bend backward due to the low resistance of the deposited flux, and the flux will be forcibly fed into the molten slag directly under the electrode, causing the temperature of the molten slag to rise. This will result in a decline. A decrease in molten slag temperature partially retards the melting of the electrode, resulting in the formation of irregular overlay beads, or even the flux not melting and passing through the electrode and appearing in the molten pool behind the electrode. In such a state, the temperature distribution of the molten pool is disturbed and welding no longer occurs. Needless to say, the sensitivity to the sprayed flux height varies depending on the melting point, specific heat, electrical conductivity, and particle size distribution of the flux. However, in order to use a wide electrode in the horizontal electroslag strip electrode overlay welding method to enable more efficient and reliable welding over a long period of time, it is necessary to devise a way to keep the spread flux height constant. (Purpose of the invention) The present invention provides a device that automatically maintains the scattered flux at a constant height during welding in wide horizontal electroslag strip electrode overlay welding, thereby achieving higher efficiency and stability. The purpose was to enable overlaying. (Structure and Effects of the Invention) The gist of the invention is a horizontal dispersion flux height adjusting device that is provided between a flux distributor and a strip electrode, and is provided with a distributed flux height adjustment device that reciprocates in the width direction of the strip electrode. Located in electroslag strip electrode overlay welding equipment. The present invention will be described below based on embodiments shown in the drawings. Figure 3 shows that among the wide strip electrodes, 150 to 200
This is an example of the present invention in a simple case with a relatively medium width of about mm. That is, a reciprocating device 6 that draws an arc in the shape of an automobile wiper, an arm 7 protruding from the reciprocating device 6, and a leveling component 8 attached to the tip of the arm 7 are connected to a flux distributor 5 and a strip electrode 2. The flux 1 constantly reciprocates in an arc shape during welding, and if even a small amount of the scattered flux 1 gathers in the front center of the strip electrode 2, it is moved to the left and right sides of the electrode 2 by the leveling part 8. Sent. The flux 1 moved from side to side serves as a weir for the molten slag 3 on both sides of the strip electrode 2. FIG. 3b is a side view of FIG. 3a, but the reciprocating device 6 and arm 7 are arranged as shown in FIG. , it is preferable to attach it at a diagonal position with respect to the electrode 2. However, when the width of the strip electrode is as wide as 250 to 300 mm, the arcuate motion may not be able to remove the accumulated flux to both sides of the strip electrode. In such a case, as shown in FIG. 4, it is preferable to move the reciprocating device 6 outside the width of the strip electrode 2 and reciprocate the arm 7 and the leveling component 8 from the lateral direction. Flux day distributor 5
When the amount of flux 1 spread is slightly too large to become molten slag 3 and starts to accumulate in front of the strip electrode 2, try to make the height of the spread flux 1 constant using the leveling component 8. is the third
The method is the same as the one shown in the figure, but in order to keep the spread flux height even more constant, it consists of a height sensor (phase difference transformer) having a rod 10 with a bearing in contact with the surface of the base material 12, and a motor. The height maintenance device 9 is integrated with the reciprocating device 6,
A rack gear 11 allows vertical movement. Although the flux distributed by the flux distributor 5 is set to almost the target height, the rail of the welding machine and the surface of the base material are not necessarily parallel, which causes a phenomenon of flux accumulation. In particular, the wider the electrode, the greater the welding heat input, and as welding passes are repeated, the thermal distortion of the base material increases, and the parallelism between the rail and the surface of the base material is impaired. Therefore, the wider the strip electrode is, the more
The method shown in the figure is effective. However, in terms of equipment cost, the method shown in Figure 3 is advantageous, so it costs 150 to 200
The method shown in Figure 3 is sufficient for a diameter of about mm. The cycle of reciprocating motion does not cause the sudden accumulation of spread flux, so there is no need for a fast cycle.
10C/S is sufficient. Also, the shape of the leveling part 8 can be changed to a rod-like shape, but as shown in FIG.
A plate-shaped one, (b) a comb-shaped (or brush-shaped) one, and (c) a rake-shaped one are preferable. The plate shape of FIG. 5a is the most efficient for scraping, but may result in over leveling or mounds of flux at the ends of the reciprocating motion. The comb shape shown in FIG. 5b can prevent excessive leveling, and no small mounds of flux will be formed at both ends of the reciprocating motion. The rake shape shown in FIG. These leveling parts may be made of metal as long as the reciprocating device itself is insulated, but the electrode width
A high current of approximately 2,500 A at 150 mm and approximately 5,000 A at electrode width of 300 mm flows through the strip electrode, so the whole part is leveled.
Alternatively, it is desirable that the tip be made of an insulating material such as alumina. (Example) An example will be described in which welding was carried out using the welding apparatus of the present invention provided with the spread flux height adjustment device of the present invention and a conventional welding device not provided with the spread flux height adjustment device. Table 1 shows the base material and strip electrode as the test materials, and Table 2 shows the flux.

【table】

[Table] * Molten flux Welding was performed using the welding conditions shown in Table 3, and as shown in FIG. 6, welded the inner bead 13 to the base metal 12 in 7 passes per layer.

[Table] The results are shown in Table 4. In the conventional method, the welder manually scrapes off the flux that had accumulated in front of the electrode during welding several times while observing with the naked eye, and was barely able to weld. On the other hand, when the wiper-like reciprocating device according to the present invention was installed, the welder was able to obtain good results without any intervention during welding.

【table】 [Brief explanation of drawings]

Fig. 1 is a side view of the strip-shaped electrode welding method, a is the horizontal electroslag method, b is the submerged arc method, Fig. 2 is a front view of the horizontal electroslag strip-electrode welding method, and Fig. 3 is a, Figures b and 4 are explanatory diagrams using the distributed flux height adjustment device of the present invention, Figures 5 a, b, and c are perspective views of the leveling parts according to the present invention, and Figure 6 is used in an example. FIG. DESCRIPTION OF SYMBOLS 1... Flux, 2... Strip electrode, 3... Molten slag, 4... Arc, 5... Flux distributor, 6... Reciprocating device, 7... Arm, 8... Leveling part , 9... Height maintenance device, 10... Bar with bearing, 11... Rack gear, 12... Base material, 13... Overlay bead.

Claims (1)

[Scope of utility model registration request] 1. A horizontal electroslag strip electrode build-up welding device, characterized in that a distributed flux height adjustment device is provided between a flux distributor and a strip electrode to reciprocate in the width direction of the strip electrode.