JPH0221182Y2 - - Google Patents

Description

[Detailed explanation of the invention] (Field of industrial application) This invention is applicable to overlay welding of stainless steel etc. on the inner surface of a pressure vessel, or to welding stainless steel to mild steel slab material etc. during the production of overlay rolled clad steel. The present invention relates to an improvement in the power supply chip of a wide band-shaped electrode overlay welding device used for overlay welding.

(Prior technology) Strip electrode overlay welding methods include submerged arc method and horizontal electroslag method depending on the type of flux, but with the development of horizontal electroslag flux and magnetic control method, electrode width Conventionally, the width of the electrode was less than 100 mm, but in recent years it has become possible to use a wide electrode of about 300 mm.

Wider electrode width allows for highly efficient overlay welding, but
As the width becomes wider, the current used also becomes higher. For example, when using a 300 mm wide electrode, a very high current of around 5000 A is used. Therefore, flux and magnetic control are also important, but with a thickness of 0.4
It is very important to uniformly conduct electricity through a wide electrode on the order of mm, and various proposals have been made so far.

For example, in Japanese Utility Model Application Publication No. 53-110925, either the guide part or the current-carrying part is a single part, and the other part is made up of a plurality of member units, each of which is provided with a spring so as to be pressed against the electrode.

In Japanese Utility Model Application Publication No. 56-45586, a small piece member is attached to the guide part and the current-carrying part, and when the guide part and the current-carrying part face each other with an electrode in between, the small piece member of the guide part and the small piece member of the current-carrying part are attached to each other. They are placed away from facing each other to strengthen the contact force.

In Japanese Utility Model Application Publication No. 60-3438, of a pair of convex and concave feeding chips, the concave part is provided with vertical grooves to reduce the contact area with the electrodes and improve the feeding performance of the electrodes. Further, in Japanese Utility Model Application Publication No. 59-135879, the electrode contactor is pressed at one point from a current-carrying part so that the electrode contactor can be freely oscillated.

As described above, various methods of supplying electricity to electrodes have been proposed to accommodate wider electrodes.
It is difficult to say that these proposals are sufficient to uniformly conduct a high current of 5000A.

With these proposals, it is difficult to adjust the pressure of the current-carrying parts or guide parts against the electrodes, and the pressure is too tight, resulting in poor electrode feeding performance, and the current-carrying performance deteriorates due to wear over time. There is. Furthermore, if electricity is applied partially in the width direction of the electrode, only the molten slag directly under the energized area will be overheated, causing a turbulent flow of the molten slag and damaging the bead shape.

In any case, failure of the power supply chip to conduct electricity may result in partial melting of the electrode before it reaches the molten pool, or conversely, an unmelted portion, leading to interruption of welding.

(Problems to be Solved by the Invention) The object of the present invention is to provide a power supply chip for overlay welding of a wide band-shaped electrode, which is capable of uniformly applying current when the width of the electrode is increased.

(Means for Solving the Problems) The gist of the present invention is to provide a power supply chip in which a band-shaped electrode 3 is held between a guide component 2 and a current-carrying component 1.
A wide strip-shaped electrode pad characterized in that a net-shaped groove 4 is provided on the contact surface 7 of the current-carrying component 1 with the strip-shaped electrode 3, and the surface that substantially contacts the strip-shaped electrode 3 consists of a plurality of island-shaped contact surfaces 5. Located in the power supply chip for welding.

The present invention will be explained in detail below.

(Function) The present invention aims to prevent bead disturbance due to uneven current application to the electrodes of the power supply chip when performing high efficiency welding by widening the electrode width in strip electrode overlay welding. It is.

With conventional full-contact power supply chips, even if the contact surface is finished with considerable precision, due to the rigidity and pressing force of the strip electrode, it is not always possible to adhere to the entire surface of the electrode, and after welding, the current-carrying parts Numerous spark marks are observed on the contact surface. If a current-carrying part with spark marks is reused in this way, the contact surface will rapidly wear out, causing uneven current flow with the electrode, causing the electrode to become red hot after passing through the power supply chip, and in severe cases, it may even reach the molten pool. Welding may be required, and this tendency becomes more pronounced as the electrodes become wider and use higher currents.

On the other hand, if you use a power supply chip that has grooves several millimeters wide in a mesh pattern (cross knurling shape) on the finished contact surface of the current-carrying parts, there will be little spark marks on the contact surface even after long periods of use. There was no red heat of the electrode during welding, and there was no occurrence of unfused electrode.

Furthermore, looking at the locations where spark marks occur, most of them occur on the island-shaped contact surface located on the lower side, but it has been known that wear is greater on the lower side of the power supply chip, so this lower island The spark marks on the contact surface are also thought to be due to wear. Therefore, when this contact surface was replaced with a member made of a silver-tungsten alloy material, it was found that no spark marks were generated on the lower island-shaped contact surface even after long-term use. In this case, the silver-tungsten alloy referred to in the present invention is an alloy having a composition of 20 to 60% Ag'40 to 80% W, and it goes without saying that it also includes sintered alloys.

Next, a commonly used power supply chip will be explained with reference to the drawings. Figure 4 shows a conventional power supply chip with an electrode width of 100 mm or less. That is, the belt-shaped electrode 3 is held between the current-carrying part 1 and the guide part 2, to which the cab tire 6 wired from the power source is connected. The entire surface 7 of the current-carrying component 1 that comes into contact with the electrode 3 is polished so as to be brought into close contact with the electrode 3. Note that the contact surfaces 7 of the guide component 2 and the current-carrying component 1 with the electrode 3 are curved in a convex and concave shape so that the thin strip-shaped electrode is fed perpendicularly to the workpiece to be welded. The parts located at the front in the welding direction have a convex shape.

The present invention is no different from conventional chips except for the shape of the contact surface 7.

(Example) Next, the present invention will be further explained with reference to an example shown in the drawings. FIG. 1 shows the power supply chip of the present invention. The contact surface of the current-carrying part 1 to which the cab tire 6 is connected with the electrode is curved to match the contact surface of the guide part 2 with the electrode so that the electrode is fed vertically, and then the entire contact surface is A mesh-like groove 4 is provided on the surface. As a result, it comes into contact with the electrode at a plurality of protruding island contact surfaces 5.
It is appropriate that the material of the current-carrying part 1 is made of copper or copper alloy, which has good electrical conductivity, but if further consideration is given to wear resistance, at least the lower island-shaped contact surface 8 should be made of abrasion-resistant material. It is effective to improve the durability of the power supply chip by embedding a silver-tungsten alloy member that has good properties in terms of both electrical conductivity and electrical conductivity. Of course, the contact surface of the silver-tungsten alloy must have good contact with the electrode, and must not deteriorate the contact condition of other island-shaped contact surfaces. In this case, it is better to make all the island-like contact surfaces made of silver-tungsten alloy, but
If at least the lower row is made of a silver-tungsten alloy, the desired effect can generally be obtained. Note that if the grooves are simply formed in a straight line, the contact surface will be island-like with multiple squares or rhombuses, but as shown in Figure 2, this island-like contact surface can be circular, oval, square, hexagonal, etc. It was confirmed that it is effective even in the shape of

Figure 3 is a cross-sectional view of the island-shaped contact surface, and it is sufficient that the depth d of the groove is 1 mm to several mm, and the corners of the island-shaped contact surface are slightly rounded to prevent sparks on the contact surface. It has been confirmed that it is useful.

Next, an example of use of the power supply chip of the present invention and a conventional power supply chip will be described.

A circular island contact surface 5 with a diameter of 10 mm is added to the original contact surface 7 with a height of 130 mm and a width of 195 mm.
A power supply chip was used, which consisted of a current-carrying part 1 in which 80 parts were processed and the bottom 8 parts were further replaced with silver-tungsten alloy (35%Ag-65%W). For comparison, a conventional power supply chip made of copper with full contact was also used.

SM41 plate thickness 90mm is used as the base material, and YB− is used as the strip electrode.
304L size 0.4 x 200mm, also flux
A CaF ₂ −TiO ₂ −SiO ₂ based melting flux was used.

The welding conditions were DCRP3200A, 30V, and 14cm/min. As a result, even after repeated use, no red heat was observed in the strip electrode, and the current was uniformly applied. On the other hand, with the conventional power supply chip, spark marks became severe from the third pass, and bead disturbances began to occur from the fifth pass.

(Effect of the invention) By using the power supply chip of the invention, 100
In overlay welding with a wide strip electrode of mm or more, a uniform current conduction state was ensured, and high efficiency and good overlay welding was achieved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a power supply chip according to an embodiment of the present invention, FIGS. 2a, b, c, and d are examples of the shape of the island-like contact surface of a power supply chip according to an embodiment of the present invention, and FIG. 3 is a diagram showing a power supply chip according to an embodiment of the present invention. FIG. 4 is a sectional view of the island-shaped contact surface of FIG. 4, and FIG. 4 is a plan view of a conventional power supply chip. 1: Current-carrying parts, 2: Guide parts, 3: Electrodes, 4:
Net-like groove, 5: Island-like contact surface, 6: Cab tire,
7: Contact surface with electrode, 8: Island-like contact surface embedded with silver-tungsten alloy, R: Roundness of corner of island-like contact surface, d: Depth of reticular groove.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a power supply chip in which a band-shaped electrode is held between a guide part and a current-carrying part, a net-like groove is provided on the contact surface of the current-carrying part with the band-shaped electrode, so that the current-carrying part is substantially connected to the band-shaped electrode. A power supply chip for welding a wide band-shaped electrode overlay, characterized in that the contact surface consists of a plurality of island-shaped contact surfaces. (2) The power supply chip for wide strip electrode overlay welding according to claim 1 of the utility model registration claim, in which a silver-tungsten alloy is embedded in at least the island-like contact surface of the lower row of current-carrying parts contact surfaces.