Welding backing plate

Abstract

To provide a novel welding backing plate that allows for precise positioning and fixing without the use of stoppers (projections). [Solution] A welding backing plate 100 is inserted into the inside of the end face 40a of a steel pipe and attached so as to protrude a predetermined amount from the end face 40a of the steel pipe, and a marking M indicating the amount to be inserted from the end face 40a is applied to the surface of the strip-shaped backing plate body 10. As a result, by using the marking M applied to the surface of the backing plate body 10 as a guide, the backing plate can be accurately positioned relative to the end face 40a of the steel pipe, and thus accurate fixing positioning can be achieved without using a stopper (projection).

Description

Technical Field

[0001] The present invention relates to a backing plate, which is an auxiliary member for steel frame welding used in column welding, pipe welding, etc.

Background Art

[0002] Conventionally, when butt-welding square steel pipes (columns) for construction or circular steel pipes, or welding a diaphragm as a reinforcing plate to the end face of a column, a backing plate is used to prevent melting and dropping (slag drop) at the welding part. This backing plate is made of, for example, a strip-shaped steel plate with a width of about 25 to 70 mm, a thickness of 9 to 12 mm, and a length of 150 to 2000 mm. Then, this backing plate is processed into an annular or U-shaped shape in advance along the inner peripheral surface of the column and then fixed by inserting it inside the end face of the column.

[0003] This backing plate needs to be fixed in a state protruding several millimeters to several tens of millimeters from the end face of the column in order to ensure the root gap during welding. However, if it is displaced or inclined during fixing, the welding part will be inclined and high-quality welding cannot be performed. Therefore, conventionally, as shown in, for example, Patent Documents 1 to 3 below, a plurality of stoppers (protrusions) are formed on the outer peripheral surface of the backing plate, that is, the surface that contacts the inside of the column end face, at positions at a certain distance from the column end face, and the backing plate is accurately fixed to the column end face by these stoppers contacting the column end face.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, as mentioned above, a structure in which a stopper (projection) is provided on the outer surface of the backing plate requires an additional work process to form the stopper (projection), leading to increased costs. Furthermore, if a stopper (projection) is formed on the outer surface of the backing plate, its position becomes fixed, and if it becomes necessary to change the fixing position of the backing plate at the work site, it becomes necessary to grind off the stopper (projection) with a grinder or similar tool, which may worsen work efficiency.

[0006] Therefore, the purpose of this invention is to solve these problems and to provide a novel welding backing plate that can be precisely fixed in position without using a stopper (projection). [Means for solving the problem]

[0007] To solve the aforementioned problems, the first invention is a welding backing plate that is inserted into the inside of the end face of a steel pipe and attached so as to protrude by a predetermined amount from the end face of the steel pipe, characterized in that the surface of the strip-shaped backing plate body is marked to indicate the amount to be inserted from the end face of the steel pipe.

[0008] With this configuration, the markings on the surface of the backing plate can be used as a guide to accurately position it relative to the end face of the steel pipe. This prevents the backing plate from being misaligned or tilted when fixed to the steel pipe. Furthermore, since the markings can be applied more easily than machining protrusions on the outer surface of the backing plate, costs are reduced. In addition, because the markings do not interfere with the end face of the steel pipe like protrusions do, the insertion depth can be easily adjusted on site.

[0009] The second invention is a welding backing plate characterized in that, in the first invention, the marking is a line extending in the longitudinal direction of the backing plate body. With this configuration, positioning can be easily and accurately achieved simply by aligning the end face of the steel pipe with the line.

[0010] The third invention is a welding backing plate characterized in that, in the second invention, multiple lines are formed in the insertion direction of the backing plate body. With this configuration, the insertion amount can be easily and accurately adjusted on site by simply selecting one of the multiple lines.

[0011] The fourth invention is a welding backing plate characterized in that, in the second or third invention, the line is made of white or fluorescent color. With this configuration, the line can be clearly seen even in a dimly lit work environment, thus improving work efficiency.

[0012] The fifth invention is a welding backing plate characterized in that, in the second or third invention, the line is formed by scribing. With this configuration, even if the surface of the backing plate body is rubbed, the line can be clearly recognized without disappearing.

[0013] The sixth invention is a welding backing plate characterized in that, in the first invention, the marking is a colored area of ​​the backing plate body. With this configuration, the amount of insertion into the steel pipe can be recognized more clearly. [Effects of the Invention]

[0014] According to this invention, since the surface of the backing plate body is marked to indicate the insertion amount into the steel pipe, it can be accurately positioned relative to the steel pipe. This prevents the backing plate from being misaligned or fixed at an angle relative to the steel pipe. Furthermore, since the marking can be applied more easily than processing a protrusion on the outer surface of the backing plate, it also reduces costs. Moreover, since the marking does not interfere with the end face of the steel pipe like a protrusion, it exhibits excellent effects such as being able to easily adjust the insertion amount on site. [Brief explanation of the drawing]

[0015] [Figure 1] This shows one embodiment of the backing plate 100 according to the present invention, and is a perspective view of the backing plate body 10 as seen from the inner side. [Figure 2] This shows one embodiment of the backing plate 100 according to the present invention, and is a perspective view of the backing plate body 10 as seen from the outside. [Figure 3] This is a perspective view showing the backing plate 100 according to the present invention in a U-shape. [Figure 4] This is an explanatory diagram showing the state of butt welding of square steel pipes 40 and 41 using the backing plate 100 according to the present invention. [Figure 5] This is an enlarged cross-sectional view showing the backing plate 100 according to the present invention fixed to the butt joint of the rectangular steel pipes 40 and 41. [Figure 6] This is a partially enlarged plan view showing another embodiment of the backing plate 100 according to the present invention. [Figure 7] This is a partially enlarged plan view showing another embodiment of the backing plate 100 according to the present invention. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. Figures 1 and 2 show one embodiment of the welding backing plate 100 according to the present invention. Figure 1 is a perspective view of the backing plate 100 according to the present invention as seen from the inner side, and Figure 2 is a perspective view of the backing plate 100 according to the present invention as seen from the outer side.

[0017] As shown in the figure, this backing metal 100 has two bending parts 20, 20 on the inner surface side of a strip-shaped steel plate backing metal body 10. The bending parts 20, 20 are each composed of a plurality of slits S extending in the width direction of the backing metal body 10. And as shown in FIG. 3, the bending parts 20, 20 can be bent at about 90° (right angle) on the inner surface side of the backing metal body 10 respectively to be formed into a U-shape.

[0018] On the other hand, a taper 30 is formed along the longitudinal direction at the corner on the outer surface side of the backing metal body 10. The size of this backing metal 100 varies so as to conform to the size of the steel pipe to be applied and is not particularly limited. For example, the length is 150 - 2000 mm, the width is 25 - 70 mm, the thickness is 9 - 12 mm, and the width of the taper 30 is 5 - 20 mm.

[0019] Also, as shown in FIGS. 2 and 3, a linear marking M is provided on the outer surface of the backing metal body 10 along the longitudinal direction. This marking M is made of paint of a color different from the color of the base metal of the backing metal body 10, and is made of a conspicuous color such as white or fluorescent color. The thickness of the line is not particularly limited, but for example, it has a thickness that can be clearly seen visually, about 1 - 3 mm.

[0020] FIG. 4 shows an application example of the backing metal 100 of the present invention on site. When the backing metal 100 of the present invention is used for butt welding of square steel pipes 40, 41 or diaphragm welding (not shown), basically, a set of two is used as shown in the figure. Specifically, as shown in FIG. 4, both ends of a pair of backing metals 100 processed into a U-shape are welded together and used in an annular (rectangular) combination.

[0021] Then, the ring-shaped backing plate 100 is inserted into the inside of the lower-positioned square steel pipe 40 from the end face with the tapered 30 facing upwards, and after aligning the line-shaped marking M with the end face 40a of the square steel pipe 40, the lower side of the backing plate body 10 is spot-welded to the inner surface of the square steel pipe 40 as shown in Figure 5.

[0022] Figure 5 shows a cross-section of a backing plate 100 fixed to the inner surface of a rectangular steel pipe 40. In this example, a line-shaped marking M is made 18 mm from the bottom edge of the backing plate body 10. By aligning this marking M with the end face 40a of the lower rectangular steel pipe 40, the backing plate 100 can be uniformly inserted to a depth of 18 mm around its entire circumference and fixed to the inside of the lower rectangular steel pipe 40. In this example, the width of the backing plate body 10 is 50 mm, so by inserting it to a depth of 18 mm, the backing plate body 10 is exposed from the end face 40a of the rectangular steel pipe 40 for a width of 32 mm from the top edge.

[0023] Then, once the backing plate 100 is fixed to the lower square steel pipe 40 in this manner, the upper square steel pipe 41 is butted against it. At this time, since a taper 30 is formed on the upper outer surface of the backing plate 100, this taper 30 acts as a guide, allowing the upper square steel pipe 41 to be butted against the lower square steel pipe 40 with high precision. Subsequently, with a root gap of several mm formed between the square steel pipes 40 and 41, build-up welding is performed along the circumferential direction of the groove, thereby preventing burn-through and allowing the square steel pipes 40 and 41 to be butted against each other with high precision.

[0024] As described above, the backing plate 100 of the present invention has markings M on the surface (outer surface) of the backing plate body 10 indicating the amount to insert into the steel pipe 40, so that it can be accurately positioned relative to the steel pipe 40. This prevents the backing plate from being misaligned or tilted when fixed to the steel pipe 40.

[0025] Furthermore, since the marking M can be applied more easily than processing a protrusion on the outer surface of the backing plate, it also reduces costs. In addition, because the marking M does not interfere with the steel pipe 40 like a protrusion, the insertion depth can be easily adjusted on site. Moreover, by forming the line-shaped marking M from white or fluorescent colors, the line can be clearly recognized even in dimly lit work sites, thus improving work efficiency.

[0026] Figures 6 and 7 show other embodiments of the marking M applied to the surface (outer surface) of the backing plate body 10. Figure 6 shows multiple line-shaped markings M formed in the insertion direction (width direction) of the backing plate body 10, allowing for easy and accurate adjustment of the insertion depth on-site by simply selecting one of the multiple lines. That is, for example, if the reference insertion depth is 20 mm from the bottom edge of the backing plate body 10, then by forming second and third lines 5 mm above and below that position, the optimal line can be selected on-site for accurate positioning.

[0027] In this case, each line can be of the same type (line type, thickness, color), but as shown in the diagram, the differences can be more clearly recognized by making the central line L1 a solid line, the line above it L2 a dotted line, and the lower line L3 a dashed line, or by changing the color and thickness of the lines.

[0028] Furthermore, as shown in Figure 7, coloring the entire insertion area allows for clearer recognition of the insertion amount than drawing a line. In addition, if multiple insertion amounts are to be indicated, a colored strip may be used. While this embodiment demonstrates application to square steel pipes, it can, of course, be applied to welding other types of steel pipes, such as round or polygonal steel pipes.

[0029] Furthermore, although this embodiment describes a backing plate body 10 with a taper 30 formed on its outer surface, it can also be applied to backing plates without a taper 30, such as those for diaphragms. In addition, the line marked by the marking M may be formed by means of a sticker or scribing (marking) in addition to paint. If the marking M is formed by scribing, the line will remain clearly visible even if the surface of the backing plate body 10 is rubbed during transport or storage. [Explanation of Symbols]

[0030] 10…Main body of the backing plate 20...Bend 30... Taper 40, 41... Rectangular steel pipes 40a...end face 100... Welding backing plate L1, L2, L3... lines M... Marking S...Slit

Claims

1. A welding backing plate that is inserted into the inside of the end face of a steel pipe and installed so as to protrude by a predetermined amount from the end face of the steel pipe, A welding backing plate characterized by having markings on the surface of the strip-shaped backing plate body indicating the insertion amount from the end face of the steel pipe.

2. In the welding backing plate according to claim 1, The welding backing plate is characterized in that the marking is a line extending in the longitudinal direction of the backing plate body.

3. In the welding backing plate according to claim 2, A welding backing plate characterized in that multiple lines are formed in the insertion direction of the backing plate body.

4. In the welding backing plate according to claim 2 or 3, The welding backing plate is characterized in that the line is colored white or fluorescent.

5. In the welding backing plate according to claim 2 or 3, The aforementioned line is formed by scribing, and is a backing plate for welding.

6. In the welding backing plate according to claim 1, The welding backing plate is characterized in that the marking is a colored area of ​​the backing plate body.

Images