JP6357401B2 - Steel plate for welding backing - Google Patents

Description

  The present invention relates to a steel plate for welding backing, and more particularly to a steel plate for welding backing used for butt welding of a welding base material that is a steel pipe and bent according to the inner dimensions of the welding base material. is there.

A steel pipe (welded base material) often used for a column of steel frame construction, for example, a round steel pipe, is joined by welding a steel pipe 102 as shown in FIG. 7 to a steel plate (called a diaphragm) as a method of joining to a beam. A so-called through-diaphragm joining method in which the beam 104 is welded to the steel plate 103 is often used. In the case of adopting this joining type, butt welding is generally used for welding the steel pipe as a column and the diaphragm steel plate, and a backing metal is used for welding. This backing metal is usually made by bending a flat bar into a circle.
In addition, examples of the welding base material as described above include elliptical steel pipes in addition to the circular steel pipes described above.

The gap between the inner surface of the curved portion of the steel pipe and the backing metal needs to be as close as possible in order to achieve good welding. In the cold-formed square steel pipe design and construction manual, the gap is specified as 1.5 mm or less, especially 0.5 mm or less is recommended for robot welding. In some cases, welding defects may occur.
As a matter of course, round steel pipes are not round in cross section due to manufacturing errors, etc., which makes it difficult to manufacture the backing metal and increases the cost, and makes it difficult to fit the steel pipe to the steel pipe. There is a problem that it is difficult.

  For this reason, some proposals have been made on the method of attaching the backing metal to the steel pipe. For example, in Japanese Patent Application Laid-Open No. 4-284997, a long slit plate to be used as a backing metal is molded and cut into a cylindrical scroll that matches the inner circumferential length of the steel pipe, and this is placed at the mounting position in the steel pipe. A method is shown in which a steel pipe is rolled and pressed against the inner wall of the steel pipe sequentially from the end with a roller or the like and fixed by spot welding. However, this method requires large-scale equipment such as a steel pipe transfer skid and a turning device, and is applicable only to a limited number of cases.

  On the other hand, as a method that can be applied without requiring such a large-scale equipment, a notched groove is formed in a flat steel to be used as a backing metal as shown in Japanese Utility Model Publication No. 63-157497, although it is for a square steel pipe. There is one that is provided in advance and bent according to the inner wall of the steel pipe when used.

  In the method of previously providing grooves in the flat steel of Japanese Utility Model Publication No. 63-157497, four square grooves each having a certain width are provided at positions corresponding to the respective corner portions of the steel pipe. Has been. However, in the backing metal shown in the embodiment, a dent is formed on the back surface of the portion where the groove was provided, resulting in a bend in a polygonal line, thereby creating a gap between the inner wall of the steel pipe and poor welding. That is, it becomes a defect in the root portion. This Japanese Utility Model Publication No. 63-157497 describes that the groove of the backing metal is appropriately changed in shape, size, depth, and number of pitches. There is no indication of what to do.

  Against the above problems, this is also for square steel pipes. However, in Japanese Patent Application Laid-Open No. 8-155679, even if there is a variation in curvature on the inner surface side of the steel pipe, there is no gap to the extent that there is no problem in welding. Steel plates for backing metal that can be kept as small as possible and are easy to process have been proposed and are actually used.

The steel plate for welding backing of steel pipes disclosed in Japanese Patent Application Laid-Open No. 8-155679 is provided in a straight state for butt welding of steel pipes, and used for bending the steel pipes according to the inner dimensions of the steel pipes. A group of 8 or more and 10 or less V-grooves is provided in a portion to be applied to the curved surface portion inside, and the depth of the V-groove is 1.7 to 4 mm less than the thickness of the backing steel plate. The angle of the V groove is 90 / n degrees or more and 110 / n degrees or less, where n is the number of V grooves in a group.
The steel pipe for welding backing of steel pipes proposed in the above-mentioned Japanese Patent Application Laid-Open No. 8-155679 has the above-described configuration. However, in order to process the V-groove, a sharp cutting blade is used. For example, the remaining plate thickness at the groove forming portion of the actual backing steel plate on the market is 3.5 mm.

In the above steel plate for backing, the remaining plate thickness is 3.5 mm, so that a simple one may be used, but there is a problem that it cannot be bent without a jig. In addition, since a cutting tool must be used for machining the groove, there are problems that it takes time to manufacture and the manufacturing cost is relatively high due to damage to the tool.
In order to be able to bend the backing steel plate without a jig, it is only necessary to reduce the thickness of the remaining plate. However, in order to perform such processing, there is a further risk of damage to the blade. In addition, there is a new problem that work is stopped and the setting must be performed again in the case of robot welding, so that work efficiency is extremely reduced. Will occur.

  Therefore, the applicant of the present application in Japanese Patent Application Laid-Open No. 2003-326391 can reconsider the groove shape so that the operator can bend without using a jig, and no disconnection occurs when robot welding is performed. A steel pipe for welding backing of the constructed steel pipe was proposed.

The steel pipe for welding backing of steel pipes described in Japanese Patent Application Laid-Open No. 2003-326391 is provided in a straight state for butt welding of a welding base material that is a steel pipe, and is bent according to the inner dimensions of the welding base material. In the steel sheet for welding backing used, a group of grooves are formed in parallel on a portion to be applied to the inner curved surface of each curved portion of the weld base material, and the shape of the groove is 50 at the depth thereof. % Or more of the portions are parallel to each other, the remaining plate thickness at the groove position is 1.5 to 2.5 mm, the width of each groove is 4 mm or less, and the radius of curvature at the corresponding curved portion is r. (Mm), the thickness of the steel plate is t (mm), the remaining plate thickness is d (mm), the groove width is a (mm), the maximum distance from the welded base metal when the steel plate is bent is s (mm), The groove pitch angle is 2e (radian), and the central angle of the corresponding curved part Is D (radian) and the number of grooves is n1 and n2,
n1 = {t− (d−d / 2)} · D · 1 / a−1
And calculating the number of grooves n1 by
cose = 1-s / r,
n2eD / 2e-1
The number of grooves n2 is calculated by
It is characterized in that the number of grooves is set to a numerical value that is greater than the larger one of n1 and n2 and the groove pitch is 2.55 mm or more.

JP-A-4-284997 Japanese Utility Model Publication No. 63-157497 JP-A-8-155679 JP 2003-326391 A

  The welding backing steel sheet disclosed in Japanese Patent Application Laid-Open No. 2003-326391 can be easily bent by human power, but since the shape of each groove is the same, when bent, FIG. As shown in Fig. 2, when it becomes U-shaped and hits the inner surface of the corner portion of the steel pipe, the center portion comes into contact with the inner surface of the corner portion, and both sides thereof are separated from the inner surface of the steel tube. It was difficult.

  Then, an object of this invention is to provide the steel plate for welding backing which can attach the whole bent steel plate (backing metal) to the inner surface of a steel pipe easily by reconsidering a groove shape.

The said subject is achieved by the steel plate for welding backing of this invention of the structure of following (1)-(12).
(1)
For butt welding of welded base metal that is a round or elliptical steel pipe, it is used by bending according to the inner dimensions of the welded base metal, and one or several pipes are arranged along the entire inner circumference of the welded base metal. Steel plate for welding backing
A portion to be applied to the inner curved surface of the weld base material is provided with a plurality of grooves extending in the width direction of the steel plate and arranged in parallel in the entire longitudinal direction of the steel plate,
Of these grooves, six or more grooves are formed deeper than the other grooves when viewed along the entire inner circumference of the weld base metal, and these deep grooves are the weld base. A steel plate for welding backing of a steel pipe, characterized by being arranged at equal intervals when viewed along the entire inner circumference of the material.
(2)
The steel sheet for welding backing according to (1), wherein the plurality of grooves between the two deep grooves have the same depth.
(3)
The remaining plate thickness in the two deep groove portions is 1.5 to 2.0 mm, and the remaining plate thickness in the groove portion between the two deep grooves is 2.0 to 2 mm. The steel sheet for welding backing of (2), which is 5 mm.
(4)
The steel sheet for welding backing according to (1), wherein the depth of the plurality of grooves between the two deep grooves is gradually shallower than the deep groove.
(5)
In the remaining plate thickness 2.0~2.5mm in the shallowest groove portion of the plurality of grooves, the residual thickness in the portion of the deepest groove is 1.5~2.0mm above (4) Steel plate for welding backing.
(6)
The shape of the groove is an arc shape or an elliptical arc shape in which the depth at the edge of the steel plate is shallower than the depth at the center portion, and the operator can bend without using a jig, and gas shield arc welding is performed. The steel sheet for welding backing according to any one of (1) to (5), wherein the steel sheet is configured not to come off when it is performed.
(7)
Minimum remaining thickness portion of said plurality of grooves is in the widthwise center of the steel plate, the plurality of grooves minimum residual thickness in the portion of the shallowest grooves at 1.7~2.2mm of said plurality of grooves (6), the minimum remaining plate thickness portion in the groove forming portion in the deepest groove portion is centered in the width direction of the steel plate, and the minimum remaining plate thickness is 1.2 to 1.7 mm. Steel plate for application.
(8)
The steel plate for welding backing according to (6) or (7), wherein the maximum remaining thickness portion is at both edges of the steel plate.
(9)
The steel sheet for welding backing according to (6), wherein a shape of the groove in the deepest groove portion of the plurality of grooves is an arc shape and a radius thereof is 50 to 255 mm.
(10)
The major axis of the groove shape in the deepest groove portion of the plurality of grooves is an elliptical arc shape parallel to the steel plate surface, and the flatness is 0.7 or less (excluding 0) (6 ) Steel plate for welding backing.
(11)
(7) The steel sheet for welding backing according to (7), wherein the grooves are provided in parallel with each other in the longitudinal direction of the steel sheet, and at both ends of the steel sheet, the pitch of the grooves is made fine and at least one is added.
(12)
A welding backing metal formed by bending the steel sheet for welding backing of any one of (1) to (11).

  In the steel sheet for welding backing of the present invention, the groove having a deeper portion is formed as compared with the conventional welding backing metal having a uniform depth of the groove for rolling the steel sheet. Since the portion is more easily bent than the other portions, for example, as shown in FIG. 4, it can be formed in a hexagonal shape, so that it is easier to follow the inner surface of the steel pipe.

  In the steel sheet for welding backing of the present invention, the depth of the groove of the welding start portion (corresponding to one of both side portions of the steel sheet) where a large arc current is generated is shallower than the groove of the conventional welding backing steel sheet. Therefore, the remaining plate thickness can be increased and the heat capacity can be increased, so that the weld drop can be prevented. That is, the backing steel sheet for welding of the present invention is easier to bend than the conventional steel sheet, and further, there is no weld drop.

FIG. 1 is a perspective view showing, as an upper surface, a surface to be the outer side of a backing steel plate having a plurality of cutout grooves for a circular steel pipe according to an embodiment of the present invention. FIG. 2 is a front view of the backing steel plate in FIG. 1 in the long side direction. FIG. 3 is a front view showing a state where the welding backing steel plate of FIG. 1 is bent and installed in a circular steel pipe. FIG. 4 is a cross-sectional view for explaining the shape of the grooves of the backing steel plate shown in FIGS. 1 and 2. FIG. 5 is a view showing a state where the steel sheet for welding backing shown in FIGS. 1 and 2 is bent and applied to a circular steel pipe. FIG. 6 is a diagram schematically showing a state at the start of welding. FIG. 7 is a diagram illustrating an example of a method of using a circular steel pipe. FIG. 8 is a view showing a state where a conventional steel sheet for welding backing is bent and applied to a circular steel pipe.

Hereinafter, a steel pipe for welding backing of a steel pipe according to an embodiment of the present invention will be described with reference to the accompanying drawings. The steel sheet for welding backing of the present invention can be any of a round steel pipe, an elliptical steel pipe, a deformed steel pipe obtained by combining a part of each of these steel pipes and a polygonal steel pipe such as a square steel pipe, etc. as a welding base material. . In the following description, a steel pipe that is a weld base material will be described as a circular steel pipe.
1 is a perspective view showing a steel pipe for welding backing of a steel pipe according to an embodiment of the present invention, FIG. 2 is a front view of the steel sheet for backing of FIG. 1, and FIG. 3 is a steel sheet for backing of FIG. It is the front view which represented with the state bent along the curve of a steel pipe.

  As shown in the perspective view of FIG. 1, the backing steel plate 1 is provided with a series of a plurality of grooves 10 extending in the width direction of the steel plate and arranged in parallel in the entire longitudinal direction of the steel plate. The illustrated example is a steel plate for welding backing for a semicircle, but depending on the inner circumference of the steel pipe that is the weld base material, it may be used for all circles, for 1/3 circles, for 1/4 circles, etc. Good. The backing metal formed by bending the welding steel plate 1 for welding is installed and used on the welding base material 102 as shown in FIG.

  The side surface shape of the groove 10 is preferably a square shape whose both side surfaces are parallel to each other as well shown in FIG. The width of each groove 10 is 4 mm or less, preferably 2 mm or less, and particularly preferably 1.75 mm or less. This width is preferably as narrow as possible in view of the above-mentioned welding omission. However, when the width becomes narrow, the number of grooves increases for the reason explained later, and processing takes time and cost. The lower limit is about 1.1 mm because of the relationship of the saw blade.

  Moreover, when arrange | positioning a groove | channel at equal intervals, it is preferable that a pitch shall be 2.55 mm or more. If this pitch is less than the above value, the remaining amount of iron in the groove forming portion becomes insufficient, and the above-mentioned disconnection is likely to occur during welding. The upper limit is that if the pitch is too large, the bent portion of the backing steel plate is not substantially arcuate, but polygonal, and the sides of the polygon and the arc of the inner surface of the steel pipe Therefore, it is desirable to set the pitch so that the gap is 0.4 mm or less.

  When the groove 10 is square as described above, it is preferable that both side walls of the groove do not interfere with each other (contact) when the backing steel plate is bent along the corner of the square steel pipe. If it is a degree)

In the embodiment of the present invention, the depth of each groove 10 is seen in the state along the entire inner circumference of the weld base metal in these grooves (see the backing metal formed of a steel plate). Therefore, when forming a backing metal with one welding backing steel plate, when forming a backing metal with two welding backing steel plates on one welding backing steel plate, When the backing metal is formed with the total number of the two welding backing steel plates and with the three welding backing steel plates, there are six or more grooves in the total number of the three welding backing steel plates. It is formed deeper than the groove. These deepened grooves are preferably arranged at regular intervals when viewed along the entire inner circumference of the weld base material. The plurality of shallow grooves between the deepened grooves preferably have the same depth.
At this time, when the bottom surface of the groove is flat, the remaining plate thickness in the deeper groove portion is 1.5 to 2.0 mm, and the remaining plate thickness in the shallow groove portion is 2.0 to 2.5 mm. It is preferable that

  FIG. 3 is a plan view showing a usage state of the backing steel plate 20. When attaching the backing metal to the steel pipe 102, the operator bends the backing steel plate 1 manually as shown in the figure to attach it to the welded base metal. As described above, at the initial stage where the backing metal is attached to the steel pipe, the bending state of the steel plate is preferably in the state shown in FIG. That is, when the depth of the six grooves is made deeper than the depth of the other grooves, as shown in FIG. If a portion between the deep grooves is struck with a hammer or the like, the portion comes along the inner surface of the steel pipe by the action of the shallow groove.

  It is preferable that the cross-sectional shape seen from the longitudinal direction of the steel plate of the groove 10 formed with the welding backing steel plate 1 is the shape shown in FIG.

  The shape (bottom shape) of the groove 10 is an arc shape or an elliptical arc shape in which the depth at the edge b of the steel plate is shallower than the depth at the central portion a. It is preferable that the minimum remaining plate thickness portion in the groove forming portion is at the center in the width direction of the steel plate. The minimum remaining plate thickness portion of the group of grooves is at the center in the width direction of the steel plate, and the minimum remaining plate thickness in the shallowest groove portion of the group of grooves is 1.7 to 2.2 mm. Among these, it is preferable that the minimum remaining plate thickness portion in the groove forming portion in the deepest groove portion is at the center in the width direction of the steel plate, and the minimum remaining plate thickness is 1.2 to 1.7 mm. If the minimum remaining plate thickness a is less than the above range, weld drop is likely to occur at that point, while if it exceeds the above range, the effect of ease of bending compared to the conventional one is reduced.

  The maximum remaining plate thickness in the groove forming portion is preferably 1.8 mm or more and 4.1 mm or less. If the maximum remaining plate thickness exceeds the above range, the effect of bendability as compared with the conventional one is reduced.

  When the groove has an arc shape, the radius is preferably 50 mm to 255 mm. When the groove has an elliptical arc shape whose major axis is parallel to the steel plate surface, the flatness is preferably 0.7 or less (not including 0 (arc)).

  As for the shape of the backing steel plate for welding, when it is bent, that is, when it is formed as a backing metal, a circular shape or an oval shape may be mentioned.

  FIG. 6 shows a welded state of a steel pipe and a diaphragm using a backing metal formed by bending the welding backing steel plate 1 shown in FIG. 1. In the initial stage of welding in which a large arc current is generated, the welding machine Since the arc is applied to the portion of the backing metal having a high heat capacity and a large remaining plate thickness, it is possible to prevent welding from being lost.

  In the above-described embodiment, the depth of the plurality of shallow grooves between the two deep grooves has been described as having the same depth, but the depth gradually increases from the groove on the deep groove side. You may comprise so that it may become shallow.

1: Backing steel plate for welding 10: Notch groove 102: Welding base material (steel pipe)
103: Welding base material (diaphragm)
104: Beam

Claims (12)

For butt welding of welded base metal that is a round or elliptical steel pipe, it is used by bending according to the inner dimensions of the welded base metal, and one or several pipes are arranged along the entire inner circumference of the welded base metal. Steel plate for welding backing
A portion to be applied to the inner curved surface of the weld base material is provided with a plurality of grooves extending in the width direction of the steel plate and arranged in parallel in the entire longitudinal direction of the steel plate,
Of these grooves, six or more grooves are formed deeper than the other grooves when viewed along the entire inner circumference of the weld base metal, and these deep grooves are the weld base. A steel plate for welding backing of a steel pipe, characterized by being arranged at equal intervals when viewed along the entire inner circumference of the material. The steel sheet for welding backing according to claim 1, wherein the plurality of grooves between the two deep grooves have the same depth. A residual thickness at the portion of the deep groove two said depth 1.5 to 2.0 mm, remaining thickness of the groove between the two is deeper grooves 2.0 to 2. The steel sheet for welding backing according to claim 2, which is 5 mm. The steel sheet for welding backing according to claim 1, wherein the depth of the plurality of grooves between the two deep grooves is gradually reduced from the deep groove side. 5. The welding according to claim 4, wherein the remaining plate thickness in the shallowest groove portion of the plurality of grooves is 2.0 to 2.5 mm, and the remaining plate thickness in the deepest groove portion is 1.5 to 2.0 mm. Steel plate for backing.   The shape of the groove is an arc shape or an elliptical arc shape in which the depth at the edge of the steel plate is shallower than the depth at the center portion, and the operator can bend without using a jig, and gas shield arc welding is performed. The steel sheet for welding backing according to any one of claims 1 to 5, wherein the steel sheet is configured so as not to come off when it is performed. Minimum remaining thickness portion of said plurality of grooves is in the widthwise center of the steel plate, the plurality of grooves minimum residual thickness in the portion of the shallowest grooves at 1.7~2.2mm of said plurality of grooves The weld backing according to claim 6, wherein the minimum remaining plate thickness portion in the groove forming portion in the deepest groove portion is centered in the width direction of the steel plate, and the minimum remaining plate thickness is 1.2 to 1.7 mm. Steel plate.   The steel plate for welding backing according to claim 6 or 7, wherein the maximum remaining thickness portion is at both edges of the steel plate. Wherein the plurality of shape of the grooves in the deepest groove portion of the of the groove is arcuate, welding backing steel plate according to claim 6 its radius is 50～255Mm. Wherein a plurality of the deepest groove elliptic shape parallel to the major axis surface of the steel sheet in the shape of the groove in the portion of of the trench, claims the aspect ratio is 0.7 or less (not including 0) 6 Steel plate for welding backing. 8. The steel sheet for welding backing according to claim 7, wherein the groove is provided in parallel with the entire length of the steel sheet, and at least one of the grooves is finely added at both ends of the steel sheet. A welding backing metal formed by bending the steel sheet for welding backing according to claim 1.