JPH0611465B2 - Method and device for automatic polishing in seam welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention automatically welds a welded portion before seam welding by superimposing the rear end portion of a leading metal strip and the leading end portion of a trailing metal strip. The present invention relates to a method of polishing and a device therefor.

[Prior art and problems to be solved by the present invention]

In a continuous strip processing line, the trailing end of the preceding strip to be wound up and the leading end of the following strip to be unwound are superposed, and the superposed part is sandwiched by a pair of electrode rollers from above and below in the strip width direction. The leading strip and trailing strip are connected by seam welding.

In such seam welding, if there is a thin oxide film or rust on the front and back surfaces of the strip in the welded part, the overall electrical resistance when the welding current passes increases, so the resistance heat at the joint decreases and It causes a decrease in strength.

Therefore, conventionally, the upper and lower surfaces of the leading strip and the trailing strip in the overlapping portion are ground by a hand grinder outside the seam welding machine.

However, in the case of manual polishing by such handling, a manual work causes a loss time of, for example, about 3 minutes, and the operating speed decreases to secure this loss time, and it is necessary to secure a plurality of workers. There are problems such as.

Incidentally, as a seam welder which has recently been put into practical use, there is a polishing method for removing slag and burrs generated in a welded portion. As shown in FIG. 7, a pair of upper and lower brush type polishing rollers 52 are arranged behind the pair of electrode rollers 50 and the pair of swaging rollers 51 in the welding proceeding direction. The purpose is to remove any slag or burrs from the welded parts by dropping them in the line during stripping, which may cause dents on the strip. It is something to do.

However, such a brush type polishing roller 5
When 2 is used for polishing before welding, the thin oxide film and the like can be removed, but the strip surface is scraped and roughened, and on the contrary, there is a problem that electrical resistance increases.

A device for grinding a welded part with a disk-shaped grindstone before welding is proposed in Japanese Patent Laid-Open No. 61-284371, which is capable of simultaneously grinding many welded parts on a steel plate. Therefore, it cannot be applied to seam welding in which the ends are overlapped.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an automatic polishing method and apparatus capable of automatically and appropriately polishing a welded portion before welding in seam welding of strips. To do.

[Means for Solving the Problems]

In the automatic polishing method according to the present invention, as shown in FIGS. 1 and 2, the trailing end portion of the preceding metal strip and the leading end portion of the following metal strip are overlapped with each other, and the overlapped portion is paired with a pair of electrode rollers. When performing seam welding by sandwiching with, a pair of roller-shaped paper grindstones capable of pressurizing the overlapping portion with a constant pressure are installed on the front side in the welding proceeding direction of the electrode roller, and the overlapping is performed by the paper grindstones. The entire front and back surfaces of the mating portion are pressed and ground with the paper grindstone before seam welding.

The automatic polishing apparatus according to the present invention, as shown in FIG. 1, includes a pair of roller-shaped paper grindstones capable of sandwiching and pressing the overlapping portion of the preceding metal strip and the following metal strip,
The pair of electrode rollers is movably installed together with the seam welder on the front side in the welding progress direction, and the pair of paper grindstones can be moved forward and backward with respect to the overlapping part surface by the reduction mechanism, and the thickness width of the paper grindstones can be adjusted. By inserting a 20 mm-deep split along the circumference at the 2/3 position, the grinding performance can be improved by making it easier to conform to the steel plate surface when pressure is applied to the overlapping part. It is composed.

[Action]

With the paper grindstone 3, it is possible to remove the thin oxide film, rust, and the like without scratching the surface of the overlapping portion L.
As a result, the conduction resistance can be reduced and the seam welding strength can be stabilized. Here, it is preferable that the rotation direction of the paper grindstone 3 is opposite to that of the electrode roller 1 and the grinding is performed in the welding proceeding direction.

Further, at the end of the overlapping portion L, it is necessary to control the pressing force in order to prevent sagging due to polishing, and it is experimentally about 5 kg. Adjust to be reasonable.

Further, if sagging occurs at the end of the overlapping portion L, the energization resistance varies, so that a portion corresponding to the overlapping portion L can be deformed by inserting a split 6 to prevent sagging of the end portion. .

The joining surface of the overlapping portion L is not polished, but the oxide film, rust and the like in this portion are thermally destroyed by the welding heat and pushed out from the welding surface by the welding pressure. Therefore, it is possible to sufficiently secure the welding strength by polishing only the upper and lower surfaces of the overlapping portion L.

〔Example〕

As shown in FIG. 1, a pair of roll-shaped paper grindstones 3
Is disposed on the front side of the electrode roller 1 so that the overlapping portion L can be sandwiched from above and below, and is rotated by the drive motor 7 and the power transmission mechanism 8. As shown in FIG. 3, such a paper grindstone 3 or the like is supported by a guide post 9 so as to be vertically movable, and the pressing force of the paper grindstone 3 can be adjusted by the lower positioning jack 5A and the pressure-reducing air cylinder 5B.

As shown in FIGS. 4 and 5, the paper grindstone 3 has a thickness T at a 2 / 3T portion corresponding to the overlapping portion L.
Cut along the circumference with a depth of 20 mm. or,
Since the paper grindstone is formed in a shape that is curved radially, the 2/3 T split position is determined by the rotation direction of the paper grindstone.

Further, in order to prevent the polishing powder from intervening in the welded portion during welding immediately after polishing, an air pro-nozzle 10 is installed on the electrode roller side of the paper grindstone 3 for powder removal.

The paper grindstone is, for example, wheel type φ125 × t19 (T) × φ12.7 # 60 (roughness), and the drive motor is a flange flat motor output 0.75W rotation speed 2800 ~ 2900RPM to ensure the polishing speed. , And be able to handle welding speed.

Figure 6 shows 1.0 (thickness) x 50 (width) x 200 (length)
An example in which the strength test sample of No. 1 was used to test the weld strength by seam welding after polishing the upper and lower front and back surfaces of the strip by conventional hunt ring hand polishing, polishing both upper and lower surfaces according to the present invention, and no polishing. Therefore, it can be seen that the strength of the welded portion of the present invention is not inferior to the conventional one and is stable.

Needless to say, the present invention can be applied to seam welding of an oxide film generation coil generated on a reprocessed steel sheet, a rust generation coil due to long-term storage, a coated steel sheet, a plated steel sheet, a stainless steel sheet, a high-tensile steel sheet, and the like.

〔The invention's effect〕

As described above, according to the present invention, since the pair of roll-shaped paper grindstones is used to polish the welded portion immediately before the electrode roller, the following effects can be obtained.

(I) Since proper polishing can be performed without making a flaw, it is possible to obtain a stable weld portion having a good seam welding strength.

(Ii) Polishing can be performed automatically before welding,
It is possible to reduce the loss time and the reduction of operating speed due to polishing in the welding cycle.

(Iii) By inserting a crack into the paper grindstone, it becomes easier to fit the surface to be polished, and it is possible to prevent sagging of the end portion.

[Brief description of drawings]

1 and 2 are a schematic front view and a schematic sectional view showing an apparatus of the present invention, and FIG. 3 is a schematic view showing a drive mechanism of a grindstone,
Fig. 5 is a front view showing the details of a paper grindstone, a side view, Fig. 6 is a graph showing the strength of a welded portion for various polishing methods, and Fig. 7 is a schematic front view showing a brush-type polishing apparatus. . 1 ... Electrode roller, 2 ... Swaging roller, 3 ...
Paper grinding stone, 4 ... Seam welding machine, 5 ... Rolling down mechanism,
5A: Positioning jack, 5B: Air cylinder, 6
... split, 7 ... drive motor, 8 ... power transmission mechanism,
9 ... Guide post, 10 ... Air blow nozzle.

Claims (2)

[Claims] 1. When the rear end portion of the preceding metal strip and the front end portion of the following metal strip are overlapped and the overlapped portion is sandwiched by a pair of electrode rollers to perform seam welding, welding progress of the electrode rollers is performed. On the front side in the direction, a pair of roller-shaped paper grindstones capable of pressurizing the overlapping portion with a constant pressure is installed, and the entire front and back surfaces of the overlapping portion are sewn by the paper grinding stones before seam welding. A polishing method in seam welding, which comprises pressurizing and grinding. 2. A pair of roller-shaped paper grindstones capable of sandwiching and pressing the overlapping portion of the preceding metal strip and the following metal strip can be moved together with the seam welder to the front side in the welding proceeding direction of the pair of electrode rollers. It is possible to move this pair of paper grindstones back and forth with respect to the surface of the superposed part by a rolling-down mechanism. An automatic polishing device in seam welding, which is characterized by improving the grinding performance by making it easier to conform to the steel plate surface when pressure is applied to the gathering portion by inserting it along the edge.