JP6922876B2 - Electrode ring, dresser of electrode ring and grinding method of electrode ring - Google Patents

Description

The present invention relates to an electrode ring, a dresser for the electrode ring, and a method for grinding the electrode ring.

Conventionally, the electrode ring of a seam welder has a flat welded portion. However, in the case of such a flat shape, the electrode ring tends to come into contact with a place other than the overlapped portion at the time of welding, so that a reactive current that does not contribute to the shape of the welded portion may occur. As a result, the welding temperature is lowered and poor penetration occurs, so that there is a problem that the strength of the welded portion is insufficient.
Insufficient strength of the welded part causes breakage of the welded part in the continuous line of the steel industry, which causes a large production loss. In order to prevent this, conventionally, a method has been adopted in which the strength of the welded portion is increased by increasing the welding current and then increasing the pressing force of the electrode ring to expand the welding nugget.
Further, as in Patent Document 1, a method of forming a recess on the surface of the electrode ring is also used.

Japanese Unexamined Patent Publication No. 61-78582

However, in the method of increasing the pressing force of the electrode ring, the plastic deformation is increased at the welded portion of the plate as the pressing force is increased. As a result, when the electrode ring comes into contact with a portion other than the welded portion (non-welded portion), the reactive current increases as described above, causing a decrease in welding strength due to insufficient penetration. In addition, it is possible to deal with this problem by reducing the pressing force during welding to suppress plastic deformation and prevent the generation of reactive current, but this method reduces the contact area between the electrode ring and the welding target. There is a problem that the welding strength is lowered because the amount of penetration is reduced. In particular, this effect was remarkable in a material in which plastic deformation easily occurs.

Further, in the case of the method of Patent Document 1, since the width of the welded portion is widened, the soundness of the welded portion is not necessarily improved. Further, the electrode ring is used once or a plurality of times, and then the outer peripheral surface is ground by a dresser. Therefore, since the processing of the concave portion of the electrode ring is removed by grinding, the reactive current prevention effect can be obtained only during the first grinding from the new state.

Therefore, the present invention has been made by paying attention to the above-mentioned problems, and can reduce the application of a current to a non-welded portion and further prevent a decrease in welding strength. It is an object of the present invention to provide a method for grinding an electrode ring.

According to one aspect of the present invention, the electrode ring for seam welding has a disk-shaped outer peripheral surface having a convex R shape having a curvature, and the radius of curvature of the R shape is 70 mm or more and 80 mm or less. An electrode ring is provided.
According to one aspect of the present invention, it is a dresser of an electrode ring that grinds the outer peripheral surface of an electrode ring for seam welding, and the disk-shaped outer peripheral surface has a concave R shape having curvature, and the outer peripheral surface is described above. It has a plurality of chevron-shaped blades provided over a surface, and the radius of curvature of the R shape is 70 mm or more and 80 mm or less, and the plurality of blades have a cutting edge angle of 50 degrees or more and 70 degrees or less and a tip radius. An electrode ring dresser having a radius of 2 mm or less is provided.
According to one aspect of the present invention, there is provided a method for grinding an electrode ring, which grinds the outer peripheral surface of the electrode ring for seam welding by using the above dresser.

According to one aspect of the present invention, there is provided a method for grinding an electrode ring, a dresser for an electrode ring, and an electrode ring, which can reduce the application of an electric current to a non-welded portion and further prevent a decrease in welding strength.

It is a figure which shows the electrode ring which concerns on one Embodiment of this invention, (A) shows the front view, (B) shows the side view. It is a partially enlarged view (example) which shows an electrode ring. It is a schematic diagram which shows the seam welder. It is a figure which shows the dresser which concerns on one Embodiment of this invention, (A) shows the front view, (B) shows the side view. It is a partially enlarged view which shows a dresser. It is a schematic diagram which shows the grinding method of an electrode ring. It is a graph which shows the distribution of the maximum and minimum difference of the welding temperature at the time of seam welding by the conventional electrode ring. It is a graph which shows the distribution of the maximum and minimum difference of the welding temperature at the time of seam welding by the electrode ring of an Example. It is a graph which shows the relationship between the use time of the dresser of an Example, and the grinding ability.

The following detailed description illustrates many specific details by exemplifying embodiments of the invention to provide a complete understanding of the invention. However, it is clear that one or more embodiments can be implemented without such particular detail description. Also, for the sake of brevity, the drawings are schematic representations of well-known structures and devices.
<Electrode ring>
The electrode ring 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3. The electrode ring 1 is equipment provided in a seam welder that seam welds steel plates to each other. The electrode ring 1 has a disk-like shape and is made of copper or a copper alloy. In the following, the disk-shaped thickness direction of the electrode ring 1 (the left-right direction in FIG. 1 (B) and the direction indicated by the arrow) is simply referred to as the "thickness direction", and the disk-shaped side surface (FIG. 1 (B)). The surface showing a part of) is called the outer peripheral surface.

As shown in FIG. 2, the electrode ring 1 has a convex R shape in which the outer peripheral surface has a curvature in which the central side in the thickness direction is convex outward in the radial direction. That is, the electrode ring 1 is formed so that the diameter on the center side is larger than that on both end sides in the thickness direction in the circular cross section viewed from the thickness direction. The radius of curvature of the R shape of the electrode ring 1 is 70 mm or more and 80 mm or less. FIG. 2 shows a case where the radius of curvature of the R shape is 75 mm as an example in the present embodiment.
Further, the electrode ring 1 is configured to be rotatable by being connected to a rotation drive device (not shown) with a circular central portion and being driven by rotation of the rotation drive device.

As shown in FIG. 3, the seam welder is provided with a pair of electrode rings 1a and 1b arranged vertically side by side so that the outer peripheral surfaces face each other. Then, in seam welding by this seam welder, two stacked steel plates 2a and 2b, which are materials to be welded, are sandwiched between a pair of electrode rings 1a and 1b, and welding is performed by applying an electric current while reducing the pressure.

In the present embodiment, by providing the R shape on the outer peripheral surface of the electrode ring 1, the contact area between the electrode ring 1 and the non-welded portion of the material to be welded can be reduced during seam welding, and the applied current can be applied. It can be concentrated on the welded part of the material to be welded. As a result, insufficient penetration during welding can be reduced, and the welding strength of the welded portion can be increased. Further, since the pressing force by the electrode ring 1 at the time of welding is also improved, the welded portion is expanded and the welding strength can be further increased. When the radius of curvature of the R shape of the electrode ring 1 is less than 70 mm, the forming range of the welding bucket is reduced, so that the welding strength may decrease. On the other hand, when the radius of curvature of the R shape of the electrode ring 1 exceeds 80 mm, the contact area between the electrode ring 1 and the non-welded portions of the steel plates 2a and 2b increases, so that the welding strength decreases due to the generation of an ineffective current.

<Electrode ring dresser>
Next, the dresser 3 of the electrode ring 1 according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5. The dresser 3 is equipment provided in the seam welder, and is equipment for grinding (dressing) the outer peripheral surface of the electrode ring 1 of the seam welder.
As shown in FIG. 4, the dresser 3 is made of a high-hardness metal (for example, cold mold steel, etc.) having a disk-like shape, capable of cutting the electrode ring 1, and having excellent wear resistance. .. Further, the dresser 3 is configured to be rotatable by receiving a rotational drive of the rotary drive device by connecting a circular central portion to a rotary drive device (not shown).

Further, the dresser 3 has a plurality of blades 4 over a circular outer peripheral surface which is a disk-shaped side surface. As shown in FIGS. 4A and 5, the plurality of blades 4 are in the thickness direction of the disk shape of the dresser 3 (the direction indicated by the arrow in FIG. 4B, and hereinafter, also simply referred to as the "thickness direction". Further, the thickness direction of the dresser 3 and the thickness direction of the electrode ring 1 are parallel to each other.) The shape is a chevron with a sharp tip. Further, the plurality of blades 4 have an angle θ of the cutting edge of 50 degrees or more and 70 degrees or less and a tip radius of 2 mm or less when viewed from the thickness direction. When the angle θ of the cutting edge is less than 50 degrees, the strength of the plurality of blades 4 is lowered, so that the cutting edge is likely to be chipped. On the other hand, when the angle θ of the cutting edge exceeds 70 degrees, the cutting edge wears with use, so that the pressing pressure tends to decrease, and the effect of improving the grinding ability cannot be sufficiently obtained. Further, when the tip radius exceeds 2 mm, the cutting edge becomes almost flat and the pressing pressure decreases, so that the effect of improving the grinding ability cannot be sufficiently obtained. Further, it is preferable that the height H of the plurality of blades 4 in the diameter direction of the dresser 3 is 2.0 mm or more and 2.5 mm or less. As shown in FIG. 5, the height H is the distance in the diameter direction of the dresser 3 from the tip of the blade 4 to the valley where the blades 4 are connected to each other. By setting the height H in the above range, the strength of the cutting edge can be maintained while the polishing ability is improved by sharpening the angle. The plurality of blades 4 have the same shape in the thickness direction.

Further, as shown in FIG. 4B, the dresser 3 has a concave R shape on the outer peripheral surface, in which the central side in the thickness direction is recessed inward in the radial direction. That is, the dresser 3 is formed so that the diameter on the center side is smaller than that on both end sides in the thickness direction in the circular cross section viewed from the thickness direction. The radius of curvature of the R shape of the dresser 3 is the same as the radius of curvature of the R shape of the electrode ring 1 in the range of 70 mm or more and 80 mm or less. FIG. 4 shows a case where the radius of curvature of the R shape is 75 mm as an example in the present embodiment.

(Grinding method of electrode ring)
Next, a method of grinding the electrode ring 1 according to the present embodiment will be described with reference to FIG. In the present embodiment, as shown in FIG. 6, the outer peripheral surface of the dresser 3 is brought into contact with the outer peripheral surface of the electrode ring 1 of the seam welder. Then, by rotating the electrode ring 1 and the dresser 3, the outer peripheral surface of the electrode ring 1 is ground. Grinding of the electrode ring 1 is performed every time welding is performed once or a plurality of times by a seam welder. Further, in the seam welder, a dresser 3 for grinding is provided for each pair of electrode rings 1 (1a, 1b) provided. Grinding by the dresser 3 is performed until the grinding amount of the electrode ring 1 becomes a predetermined amount (for example, 2 mm) or more. In the present embodiment, by using the dresser 3 having a concave R shape on the outer peripheral surface, the R shape is formed on the outer peripheral surface of the electrode ring 1 according to the R shape of the dresser 3. Therefore, regardless of the number of times the electrode ring 1 is ground, the above effect can be obtained by forming the outer peripheral surface of the electrode ring 1 into an R shape.

_{Further, in the present embodiment, the grinding capacity dave} (mm / hr) represented by the equation (1) is 2.0 mm / hr or more with respect to the usage time (time used for grinding) of the dresser 3. It is preferable to use the dresser 3. Grinding capacity _dave is the amount of grinding per hour. Further, t is the time (hr) used for grinding the dresser. That is, as shown in the equation (2), the grinding time T (hr) is calculated from the relationship between _{the grinding capacity dave and the target grinding amount D (mm).} The grinding time T is the time required for grinding to be the grinding amount D.
d _ave = −0.15 × t + 4 ・ ・ ・ (1)
T = D / _dave ... (2)

Since the tip of the dresser 3 is worn by grinding, the grinding capacity _dave decreases according to the usage time, and the grinding time T becomes long. Therefore, high grinding ability is maintained by adjusting the timing of replacing the dresser 3 so _{that the allowable grinding ability dave} and the grinding time T are obtained by using the equations (1) and (2). be able to.

<Modification example>
Although the present invention has been described above with reference to specific embodiments, it is not intended to limit the invention by these descriptions. By reference to the description of the invention, one of ordinary skill in the art will appreciate the disclosed embodiments as well as other embodiments of the invention that include various modifications. Therefore, it should be understood that the embodiments of the invention described in the claims also include embodiments including these modifications described in the present specification alone or in combination.

For example, in the above embodiment _{, the dresser 3 is used under the condition that the grinding ability ave} calculated by the equation (1) is 2.0 mm / hr or more, but the present invention is not limited to such an example. _{The grinding ability dave} calculated by the equation (1) is the most suitable relational expression under the initial condition that the angle θ of the cutting edge of the blade 4 is 60 degrees and the tip radius is 1.0 mm. A relational expression other than the equation (1) may be used due to the difference in radius. Further, the tip radius of the blade 4 of the dresser 3 in the initial unused state may be set to less than 2 mm, and the dresser 3 may be replaced at the timing when the tip radius exceeds 2 mm.

Further, R-shapes may be provided on both ends of the dresser 3 in the thickness direction so that the diameters of both ends of the disc-shaped dresser 3 in the thickness direction become large. By doing so, it is possible to adjust the width of the electrode ring 1 and the like at the time of grinding.
Further, in the above embodiment, the electrode ring 1 having an R shape on the outer peripheral surface is ground by the dresser 3, but the present invention is not limited to this example. For example, an electrode ring having no R shape on the outer peripheral surface may be ground by a dresser 3, and an R shape having a radius of curvature of 70 mm or more and 80 mm or less may be provided on the outer peripheral surface of the ground electrode ring 1. ..

<Effect of embodiment>
(1) The electrode ring 1 according to one aspect of the present invention is an electrode ring 1 for seam welding, and the disk-shaped outer peripheral surface has a convex R shape having a curvature, and the radius of curvature of the R shape. Is 70 mm or more and 80 mm or less.
According to the configuration of (1) above, the contact area between the electrode ring 1 and the non-welded portion of the material to be welded can be reduced, and the application of current to the non-welded portion can be reduced, so that the applied current can be reduced. Can be concentrated on the welded part of the material to be welded. Further, since the pressing force by the electrode ring 1 at the time of welding is also improved, the welded portion can be enlarged. As a result, the generation of reactive current is suppressed, and the insufficient penetration during welding is reduced, so that the welding strength can be increased.

(2) The dresser 3 of the electrode ring 1 according to one aspect of the present invention is the dresser 3 of the electrode ring 1 that grinds the outer peripheral surface of the electrode ring 1 for seam welding, and has a disk-shaped outer peripheral surface in the thickness direction. Has a concave R shape whose central side is recessed inward in the radial direction, and has a plurality of chevron-shaped blades 4 provided over the outer peripheral surface, and the radius of curvature of the R shape is 70 mm or more and 80 mm or less. The blade 4 has a cutting edge angle of 50 degrees or more and 70 degrees or less, and a tip radius of 2 mm or less.
According to the configuration of the above (2), the R shape of the outer peripheral surface can be made within the range of the above (1) by grinding. As a result, the effect of the above configuration (1) can be achieved by forming the outer peripheral surface of the electrode ring 1 into an R shape regardless of the number of times of grinding. That is, the effect of preventing the generation of reactive current due to the R shape of the electrode ring 1 can be maintained until the electrode ring 1 reaches the usage limit. Further, according to the configuration of (2) above, by sharpening the plurality of blades 4 of the dresser 3, the contact area between the electrode ring 1 and the dresser 3 in the circumferential direction can be reduced during grinding, and the dresser 3 can be pushed. The applied pressure can be increased. As a result, the grinding ability can be significantly improved and the grinding time can be significantly shortened as compared with the conventional dresser having a flat tip of the blade. Further, by setting the angle of the cutting edge within the above range, it is possible to prevent the cutting edge from being chipped during grinding.

(3) In the method for grinding the electrode ring 1 according to one aspect of the present invention, the outer peripheral surface of the electrode ring 1 for seam welding is ground by using the dresser 3 having the configuration of (2) above.
(4) In the configuration of (3) above, the dresser 3 is used under the condition that the _{grinding ability ave calculated by the equation (1) is 2.0 mm / hr or more with respect to the usage time of the dresser 3.}
According to the configuration of (4) above, the grinding ability can be maintained by a simple method using the usage time.

Next, the examples carried out by the present inventors will be described. In the embodiment, seam welding was performed a plurality of times using the electrode ring 1 according to the above embodiment and the conventional electrode ring having a flat outer peripheral surface, and the maximum and minimum differences in welding temperatures during welding were confirmed. In the examples, the radius of curvature of the R shape of the electrode ring 1 was 75 mm. The welding conditions other than the difference in the shape of the electrode ring were the same. Further, the welding temperature is the surface temperature of the welded portion immediately after welding.

FIG. 7 shows the distribution of the maximum and minimum differences in welding temperature in the conventional seam welding using an electrode ring having a flat outer peripheral surface. FIG. 8 shows the distribution of the maximum and minimum differences in welding temperatures in seam welding using the electrode ring 1 according to the above embodiment. As shown in FIGS. 7 and 8, it was confirmed that in the conventional electrode ring, plastic deformation occurred during welding and the reactive current increased, so that the temperature deviation during welding increased. On the other hand, when the electrode ring 1 having an R-shaped radius of curvature of 75 mm was used, it was confirmed that the temperature deviation was suppressed and the increase in the reactive current could be prevented. From this, it was confirmed that the electrode ring 1 according to the above embodiment shows good results for the problem of welding strength decrease due to poor penetration due to welding temperature deviation.

In addition, in the examples, the decrease in grinding ability due to the increase in the cumulative usage time of the dresser 3 was also investigated. FIG. 9 shows the relationship between the cumulative usage time of the dresser 3 and the grinding ability according to the above embodiment. As shown in FIG. 9, the cumulative usage time and the grinding ability have a relationship satisfying the equation (1), and by using the equation (1), the grinding ability according to the usage time can be estimated accurately. It could be confirmed. Further, in the case of the conventional dresser having a flat cutting edge, it was confirmed that the grinding capacity was about 0.5 mm / hr, although the grinding capacity did not change significantly with respect to the cumulative grinding time. Therefore, it was confirmed that the dresser 3 according to the above embodiment has a high grinding ability at a usage time of about 20 hr.

1,1a, 1b Electrode ring 2a, 2b Steel plate 3 Dresser 4 Blades

Claims (3)

An electrode ring for seam welding that seam welds steel plates together.
The disk-shaped outer peripheral surface has a convex R shape having a curvature formed so that the diameter on the central side is larger than that on both end sides in the thickness direction in a circular cross section viewed from the thickness direction.
Radius of curvature of the R shaped state, and are more 80mm or less 70 mm,
Ing of copper or a copper alloy, the electrode wheels. A dresser for an electrode ring that grinds the outer peripheral surface of an electrode ring made of copper or a copper alloy for seam welding that seam welds steel plates to each other.
The disk-shaped outer peripheral surface has a concave R shape having a curvature in which the central side in the thickness direction is recessed inward in the radial direction.
It has a plurality of chevron-shaped blades provided over the outer peripheral surface, and has a plurality of chevron-shaped blades.
The radius of curvature of the R shape is 70 mm or more and 80 mm or less.
Wherein the plurality of blades is the angle of the cutting edge is 70 degrees or less than 50 degrees state, and are tip radius is 2mm or less,
The disk-shaped outer peripheral surface has a convex R shape having a curvature formed so that the diameter on the center side is larger than that on both end sides in the thickness direction in a circular cross section viewed from the thickness direction. the radius of curvature of the shape of the R-shaped, the electrode wheels Ru obtained is 70mm or more 80mm or less, the electrode wheels of the dresser. A method for grinding an electrode ring, which grinds the outer peripheral surface of the electrode ring for seam welding using the dresser according to claim 2.

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