JPH0221193Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) This invention is applicable when overlaying the inner surface of a pressure vessel with stainless steel, etc., or when overlaying stainless steel, etc. on a mild steel slab material during the production of overlay rolled clad steel. The present invention relates to an improvement in the power supply chip of a horizontal electroslag strip-shaped electrode overlay welding device used for the welding device. (Prior art) The thickness of the electrode used in strip electrode overlay welding is as thin as 0.4 mm in Japan. The power supply chips 5 and 6 used for this generally have a concave shape with respect to the welding direction to prevent the thin electrode from bending, as shown in the plan view of Fig. 2a, but as shown in the side view of Fig. 2b and the front view of c. The lower part of the power supply chip is flat. By the way, there are two types of strip electrode overlay welding methods: a submerged arc method and a horizontal electroslag method.
In the past, the submerged arc method was used, but it was discovered that the horizontal electroslag method could be used with the same welding equipment by using a flux with good electrical conductivity, and the horizontal electroslag method, which is easier to widen, has recently come into use. Ta. Conventional techniques for improving power supply chips that can also be used in the horizontal electroslag method include Japanese Patent Application No. 56-500704, Japanese Patent Application Laid-Open No. 52-86945,
There are various publications such as JP-A No. 55-126391, JP-A-53-110925, JP-A-50-159845, and JP-A-56-45586. However, except for those that utilize electromagnetism, these mainly improve the electrical conductivity between the electrodes. By the way, if the width of the electrode is increased while maintaining a concave power supply chip with a normal radius of curvature, the flux scattered in front of the electrode during welding will accumulate during welding, overcome the resistance of the flux, and cause the electrode to become wider as shown in Figure 3. The end of 1 may be bent backwards. For submerged arc method, electrode width is 75mm
There was no problem because the arc was more likely to occur from the electrode end, but in the case of the horizontal electroslag method, the electrode width was 200 mm or 300 mm.
mm wide, the central part of the molten pool becomes hot and the electrical conductivity of the molten slag increases, so the current flows through the center of the electrode and becomes difficult to flow to both ends.As shown in Figure 4, the unmolten electrode 1a It may occur in some areas. Of course, in this case welding must be interrupted. It is also possible to increase the thickness of the electrode to prevent bending, but this will degrade welding workability, so flux must be considered first, and it is not easy to make the electrode wider with a thicker wall. (Problems to be solved by the invention) The purpose of the invention is to provide a power supply chip for welding strip-shaped electrodes that can prevent bending of the electrode without increasing the thickness of the electrode even if the electrode is wide. . (Means for Solving the Problems) The gist of the present invention is that a power supply chip 5, which holds an electrode 1 for horizontal electroslag strip electrode overlay welding,
6, the power supply tip for horizontal electroslag band-like overlay welding is characterized by having power supply tip protrusions 6a in the feeding direction of the electrode 1 at both ends of the power feeding chip 6 on the rear side with respect to the welding progress direction. It is in. The present invention will be explained in detail below with reference to the drawings. FIG. 1 shows the implementation status of the present invention. The feeding tip 5 at the front in the direction of welding progress has a convex shape, and the feeding tip 6 at the rear has a concave shape, and the electrode 1 is fed with a shape to prevent bending. A flux 2 is spread in front of the electrode, and a molten pool 3 is formed behind the electrode, followed by a solidified slag 4. A cab tire 7 from a power source is connected to the power supply chip 6. The distance between the parallel portion 6b of the lower part of the power supply chip and the surface of the base material 8 is kept constant as the electrode protrusion length D. Power feeding chip protrusions 6a are provided at both ends of the rear power feeding chip 6. (Function of the invention) This invention uses a horizontal electroslag method, and the electrode
This is intended to increase the width to more than 200mm and increase efficiency. If the electrode width is relatively narrow, about 75 mm, the bead width will not become nearly narrower than the electrode width even if the electrode is curved with the power supply chip to prevent bending, but if the electrode width is 200 mm or more, the bead will be completely bent. If an attempt is made to prevent this, the electrode will have to be curved considerably, depending on its rigidity, and the bead width will be considerably narrower than the original electrode width, resulting in a loss in terms of high efficiency. If possible, I don't want the electrode to be too curved. Another option would be to increase the rigidity of the electrode, but since the electrode would become spring-like and difficult to handle, and the power supply chip would be subject to severe wear, it would be better if a slightly softer electrode could be used. For this reason, it is desirable that the rigidity of the electrode be not so high and that the curvature of the electrode be as narrow as possible. Therefore, as shown in FIG.
By using the power feeding chip of the present invention provided with a, even if both ends of the electrode are pushed by the scattered flux, they are mechanically supported and can be welded without bending. Additionally, the present invention has advantages in terms of welding phenomena. Generally, in the case of welding a strip electrode overlay, the electrode protrusion length D is kept at approximately 30 to 50 mm in order to make the electrode easier to melt due to Joule heat. Figure 2 a, b, c
When using a general power supply chip such as the submerged arc method, the current flowing through the electrode tends to be concentrated at both ends of the electrode, but as mentioned earlier, in the electroslag method, the center of the molten pool is hot and has high electrical conductivity. Therefore, it tends to flow through the center of the electrode. When a power supply chip having power supply chip protrusions at both ends as in the present invention is used, current tends to flow at both ends of the electrode, which in turn results in high temperatures at both ends of the molten pool. Therefore, the unmelted electrode 1a shown in FIG. 4 will not occur if the power supply chip of the present invention is used. In this case, the length L of the power feeding chip protrusion is 1/5 to 1/2 of the electrode protrusion length D.
Within this range, the effect can be sufficiently obtained. Further, the width W of the protruding portion of the feeding chip must satisfy the relationship B>2×W with respect to the width B of the parallel portion of the bottom of the feeding chip. (Example) An example using the power supply chip of the present invention in which the length L of the power supply chip protrusion 6a is 20 mm and the conventional power supply chip shown in FIG. 2 will be described. Table 1 shows the base material and electrode as the test material, and Table 2 shows the flux.

【table】

[Table] Welding was performed in three passes per layer under the welding conditions shown in Table 3.

[Table] As a result, as shown in Table 4, in the conventional power supply chip, not only the bead widths were uneven, but also welding was interrupted twice due to bending of the electrode during welding.

[Table] (Effects of the invention) By using the power supply chip of the invention, even when using a softer electrode in horizontal electroslag strip electrode overlay welding, it is possible to create a wide electrode of 200 mm or more and achieve highly efficient overlay welding. did it.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the present invention, Fig. 2 a, b, and c are conventional power feeding chips, a is a plan view thereof, b is a side view thereof, c is a front view thereof, and Fig. 3 is an electrode by a conventional feeding chip. FIG. 4 is a side view showing the bending condition, and a perspective view showing that the electrode is severely bent and some unmelted electrodes are formed. 1 is an electrode, 1a is an unmolten electrode, 2 is a flux, 3 is a molten pool, 3' is a molten metal, 4 is a solidified slag, 5 is a front power supply chip, 6 is a rear power supply chip, 6a is a power supply chip protrusion 6b is the parallel part of the bottom of the power feeding chip, 7 is the cap tire, 8 is the base material, B is the width of the parallel part of the bottom of the power feeding chip, L is the length of the protruding part of the feeding chip, W is the width of the protruding part of the feeding chip, D is the electrode protrusion length (distance between the base material and the parallel part of the bottom of the power supply chip).

Claims (1)

[Scope of utility model registration request] A power supply chip that holds an electrode for horizontal electroslag strip electrode overlay welding, characterized by having power supply chip protrusions in the electrode feeding direction at both ends of the power supply chip on the rear side with respect to the welding progress direction. Power supply chip for horizontal electroslag strip electrode overlay welding.