JP6928966B2 - Backing material for reinforcing bar welding - Google Patents

Description

The present invention relates to a backing material for reinforcing bar welding.

According to Patent Document 1 and the like, a ceramic backing material used for welding reinforcing bars to each other is known.

Japanese Patent No. 3674272

Welding using the backing material described above is performed in a state where the backing material is attached to the reinforcing bar so as to cover the gap between the end portions formed by bringing the ends of the reinforcing bar close to each other.
The tips of the welding rods are brought close to the gaps between the ends of the reinforcing bars, and the welding material is poured into the space surrounded by the ends of the reinforcing bars and the backing material to weld the reinforcing bars to each other.
When welding, the operator visually confirms that the welding material has been sufficiently poured into the space. However, since the backing material can be formed from various ceramics, it may be difficult to visually confirm this in some cases.
An object of the present invention is to provide a backing material for reinforcing bar welding, which makes it easy to visually confirm the welding work.

In order to achieve the above object, according to the present invention, there is provided a backing material for reinforcing bar welding, which comprises a ceramic material containing _{SiO 2} and Al ₂ O _{3 as main components and has a hunter whiteness of 59 or more.}

According to the present invention, there is provided a backing material for reinforcing bar welding that makes it easy to visually confirm the welding work.

It is a perspective view which shows the backing material of this embodiment. It is a schematic diagram at the time of welding the reinforcing bars by using the backing material. It is a table which shows the hunter whiteness and the ease of identification of Examples 1 to 14 and Comparative Examples 15 to 18. It is a table which shows the composition of the ceramics used in Examples 1 to 14 and Comparative Examples 15 to 18. It is a graph which shows the relationship between the hunter whiteness and _{the content of Fe 2} O _3.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a perspective view showing a backing material 10 for reinforcing bar welding according to the present embodiment. As shown in FIG. 1, the backing material 10 of the present embodiment is a member extending in the longitudinal direction and has a U-shaped cross section.

FIG. 2 is a schematic view showing a state in which reinforcing bars 2 and 3 are welded to each other using the backing material 10. FIG. 2 shows a cross section of the reinforcing bars 2 and 3 along the longitudinal direction. As shown in FIG. 2, the backing material 10 is used when welding the reinforcing bars 2 and 3 to each other.

A procedure for welding the reinforcing bars 2 and 3 using the backing material 10 of the present embodiment will be described.
First, the welding operator arranges the ends of the reinforcing bars 2 and 3 so as to face each other through a predetermined gap G. Next, the operator attaches the backing material 10 to the reinforcing bars 2 and 3 so as to cover the gap G. When welding the reinforcing bars 2 and 3 extending in the horizontal direction as shown in FIG. 2, the backing material 10 is arranged so that the bottom portion 11 of the U-shaped backing material 10 covers the lower part of the gap G. .. The backing material 10 may be supported on the reinforcing bars 2 and 3 by a mounting jig (not shown), or the backing material 10 may be supported by a hand wearing leather gloves by an operator. In addition, because of the speed of work, it is preferable for the worker to support the backing material 10 by hand without using a mounting jig.

The operator welds the reinforcing bars 2 and 3 to each other by arc welding. The operator welds the gap G so as to fill the gap G with the welding material 22 in which the welding rod 21 is melted. An arc is generated between the reinforcing bars 2 and 3 and the welding rod 21 to melt the welding rod 21 and the reinforcing bars 2 and 3, and the welding material 22 is poured into the gap G between the ends of the reinforcing bars 2 and 3 to form a bead. do. Since the U-shaped backing material 10 covers the gap G, the welding material 22 stays in the gap G without falling, and the reinforcing bars 2 and 3 can be reliably welded to each other.

When the welding material 22 is applied to the entire end faces of the reinforcing bars 2 and 3 and the welding is completed, the backing material 10 is removed from the reinforcing bars 2 and 3. The surface 12 of the backing material 10 facing the gap G is melted by the heat during welding, and the surface 12 of the backing material 10 is adhered to the welding material 22. Therefore, when an operator hits both ends 13 (see FIG. 1) of the U-shaped backing material 10 with a hammer or the like, the backing material 10 cracks around the bonded surface 12 and is easily backed. The backing material 10 can be removed from the reinforcing bars 2 and 3.

The backing material 10 used for welding as described above is a _{ceramic containing SiO 2} and Al ₂ O ₃ as main components. The melting point of the backing material 10 is preferably about 1000 ° C. to 1200 ° C. For example, the backing material 10 can be formed by a ceramic called cordierite.

The worker performs welding while confirming that the welding material 22 is sufficiently poured into the gap G between the reinforcing bars 2 and 3 through the protective glasses. If the surface 12 of the backing material 10 can be seen from the gap G between the reinforcing bars 2 and 3, it means that the welding material 22 has not yet been sufficiently poured into the gap G. The operator determines that the welded material 22 has been sufficiently poured into the gap G when the surface 12 of the backing material 10 cannot be seen from the gap between the reinforcing bars 2 and 3.

By the way, the gap G between the reinforcing bars 2 and 3 is about 5 to 10 mm, although it depends on the thickness of the reinforcing bars to be welded. For example, when welding a reinforcing bar having a nominal diameter of 50 mm, a gap G of about 10 mm is provided. That is, the gap G has a narrow (10 mm) and deep (50 mm) shape, and when the welding rod 21 is arranged in the vicinity of the gap G, the backing material 10 located at the bottom of the gap G passes through the gap G. It is difficult to try to see the surface 12.

As described above, the surface 12 of the backing material 10 is difficult to see even for free, but it becomes more difficult to see due to the color of the backing material 10. Since the backing material 10 can be formed by various ceramics, there are backing materials 10 having various shades. However, it is difficult to distinguish the dark-colored backing material 10 from the reinforcing bars 2 and 3.

Moreover, the protective glasses have a high shading rate to protect the eyes from arcs. Therefore, even if the contours of the reinforcing bars 2 and 3 and the surface 12 of the backing material 10 can be sufficiently distinguished when checking with the naked eye without wearing protective glasses before welding, if protective glasses are worn at the time of welding. , It may be difficult to distinguish the contours of the reinforcing bars 2 and 3 from the surface 12 of the backing material 10. Therefore, the backing material 10 of the present embodiment has a hunter whiteness of 59 or more. The hunter whiteness is an index of whiteness expressed by the measurement method specified in JIS P 8123.

<Example>
As shown in FIG. 3, Examples 1 to 14 and Comparative Examples 15 to 18 having different hunter whiteness were prepared, and their respective hunter whiteness and ease of identification were evaluated. Examples 1 to 3 were formed of ceramics having a common composition A. Similarly, Examples 4 to 6 are prepared from ceramics having a common composition B, Examples 7 to 9 are prepared from ceramics having a common composition C, and Examples 10 to 10 are prepared from ceramics having a common composition D. 12 is prepared, Example 13 is prepared from the ceramics having the composition E, Example 14 is prepared from the ceramics having the composition F, Comparative Example 15 is prepared from the ceramics having the composition G, and the ceramics having the composition H are prepared. Comparative Example 16 was prepared, Comparative Example 17 was prepared from the ceramics having the composition I, and Comparative Example 18 was prepared from the ceramics having the composition J.

The compositions A to F are shown in FIG.
Composition A is shown in FIG. SiO ₂ : 61.00 wt%, Al ₂ O ₃ : 25.40 wt%, Fe ₂ O ₃ : 1.50 wt%, TiO ₂ : 0.74 wt%, CaO: 2.15 wt%, MgO: 7.65 wt%, Na ₂ O: 0.13 wt%, K ₂ O: 1.24 wt%.
Composition B is SiO ₂ : 68.20 wt%, Al ₂ O ₃ : 22.70 wt%, Fe ₂ O ₃ : 1.11 wt%, TiO ₂ : 0.43 wt%, CaO: 0.50 wt%, MgO: 1. .13 wt%, Na ₂ O: 1.22 wt%, K ₂ O: 4.24 wt%.
The composition C is SiO ₂ : 68.00 wt%, Al ₂ O ₃ : 28.80 _{wt%, Fe 2} O ₃ : 0.50 wt%, TiO ₂ : 0.34 wt%, CaO: 0.18 wt%, MgO: 0. .44 wt%, Na ₂ O: 0.45 wt%, K ₂ O: 0.89 wt%.
Composition D is SiO ₂ : 43.80 wt%, Al ₂ O ₃ : 43.10 wt%, Fe ₂ O ₃ : 0.74 wt%, TiO ₂ : 0.68 wt%, CaO: 0.83 wt%, MgO: 9 .40 wt%, Na ₂ O: 0.23 wt%, K ₂ O: 1.14 wt%.
The composition E is SiO ₂ : 62.63 wt%, Al ₂ O ₃ : 26.31 wt%, Fe ₂ O ₃ : 0.40 wt%, TiO ₂ : 0.51 wt%, CaO: 0.38 wt%, MgO: 0. .12 wt%, Na ₂ O: 1.30 wt%, K ₂ O: 2.43 wt%.
The composition F is SiO ₂ : 42.82 wt%, Al ₂ O ₃ : 39.84 wt%, Fe ₂ O ₃ : 0.70 wt%, TiO ₂ : 0.55 wt%, CaO: 14.22 wt%, MgO: 0. .28 wt%, Na ₂ O: 0.47 wt%, K ₂ O: 0.54 wt%.
The composition G is SiO ₂ : 72.14 wt%, Al ₂ O ₃ : 18.23 wt%, Fe ₂ O ₃ : 1.02 wt%, TiO ₂ : 0.39 wt%, CaO: 0.54 wt%, MgO: 0. .15 wt%, Na ₂ O: 2.06 wt%, K ₂ O: 4.35 wt%.
Composition H is SiO ₂ : 71.82 wt%, Al ₂ O ₃ : 18.08 wt%, Fe ₂ O ₃ : 1.32 wt%, TiO ₂ : 0.36 wt%, CaO: 0.57 wt%, MgO: 0. .20 wt%, Na ₂ O: 4.27 wt%, K ₂ O: 18.08 wt%.
Composition I is SiO ₂ : 67.29 wt%, Al ₂ O ₃ : 20.80 wt%, Fe ₂ O ₃ : 5.32 wt%, TiO ₂ : 0.56 wt%, CaO: 0.38 wt%, MgO: 2 .43 wt%, Na ₂ O: 0.36 wt%, K ₂ O: 2.25 wt%.
The composition J is SiO ₂ : 65.65 wt%, Al ₂ O ₃ : 23.83 wt%, Fe ₂ O ₃ : 1.69 wt%, TiO ₂ : 0.40 wt%, CaO: 0.36 wt%, MgO: 0. .33 wt%, Na ₂ O: 1.63 wt%, K ₂ O: 3.26 wt%.

Ease of identification was performed by a sensory test by a skilled welder. The contour of the reinforcing bar and the surface of the backing material were easily identified as 1, those that were not impossible to identify were 2, and those that were difficult to identify were evaluated on a three-point scale. FIG. 4 shows the evaluation results of the hunter whiteness and the ease of identification of Examples 1 to 14 and Comparative Examples 15 to 18.

<Examples 1 to 3>
The hunter whiteness of the backing material of Example 1 was 61.04. The ease of identification of the backing material of Example 1 was 2.
The hunter whiteness of the backing material of Example 2 was 59.71. The ease of identification of the backing material of Example 2 was 2.
The hunter whiteness of the backing material of Example 3 was 60.06. The ease of identification of the backing material of Example 3 was 2.

<Examples 4 to 6>
The hunter whiteness of the backing material of Example 4 was 74.18. The ease of identification of the backing material of Example 4 was 1.
The hunter whiteness of the backing material of Example 5 was 71.41. The ease of identification of the backing material of Example 5 was 1.
The hunter whiteness of the backing material of Example 6 was 71.11. The ease of identification of the backing material of Example 6 was 1.

<Examples 7 to 9>
The hunter whiteness of the backing material of Example 7 was 83.20. The ease of identification of the backing material of Example 7 was 1.
The hunter whiteness of the backing material of Example 8 was 84.21. The ease of identification of the backing material of Example 8 was 1.
The hunter whiteness of the backing material of Example 9 was 84.99. The ease of identification of the backing material of Example 9 was 1.

<Examples 10 to 12>
The hunter whiteness of the backing material of Example 10 was 88.72. The ease of identification of the backing material of Example 10 was 1.
The hunter whiteness of the backing material of Example 11 was 87.23. The ease of identification of the backing material of Example 11 was 1.
The hunter whiteness of the backing material of Example 12 was 89.49. The ease of identification of the backing material of Example 12 was 1.

<Examples 13 and 14>
The hunter whiteness of the backing material of Example 13 was 78.33. The ease of identification of the backing material of Example 13 was 1.
The hunter whiteness of the backing material of Example 14 was 85.34. The ease of identification of the backing material of Example 14 was 1.

<Comparative Examples 15-18>
The hunter whiteness of the backing material of Comparative Example 15 was 43.0. The ease of identification of the backing material of Comparative Example 15 was 3.
The hunter whiteness of the backing material of Comparative Example 16 was 36.7. The ease of identification of the backing material of Comparative Example 16 was 3.
The hunter whiteness of the backing material of Comparative Example 17 was 29.75. The ease of identification of the backing material of Comparative Example 17 was 3.
The hunter whiteness of the backing material of Comparative Example 18 was 42.30. The ease of identification of the backing material of Comparative Example 18 was 3.

From the above results, it was confirmed that when the hunter whiteness is 59 or more, the contour of the reinforcing bar and the surface of the backing material can be discriminated. Further, if the hunter whiteness is 70 or more, it is easier to distinguish. In order to make the hunter whiteness 59 or more, _{the content of Fe 2} O ₃ is preferably 1.50 wt% or less.

FIG. 5 is a graph showing the relationship between _{the hunter whiteness and the content of Fe 2} O _3.
The hunter whiteness was considered to be high in the content _{of Fe 2} O _{3 in the ceramics.} In addition, in order to prepare FIG. 5, the average value of the hunter whiteness was calculated for Examples 1 to 3 having the common composition A, and the average value of the hunter whiteness was calculated for Examples 4 to 6 having the common composition B. Was calculated, the average value of hunter whiteness was calculated for Examples 7 to 9 having a common composition C, and the average value of hunter whiteness was calculated for Examples 10 to 12 having a common composition D.
As shown in FIG. 5, the _{higher the content of Fe 2} O ₃ , the lower the hunter whiteness tended to be. Therefore, in order to make the hunter whiteness 59 or more, _{the content of Fe 2} O ₃ is preferably 1.50 [wt%] or less. _{More preferably, the content of Fe 2} O ₃ is preferably 1.00 [wt%] or less in order to make the hunter whiteness 70 or more.

Although the embodiments of the present invention have been described above, it goes without saying that the technical scope of the present invention should not be construed as being limited by the description of the present embodiments. It is understood by those skilled in the art that the present embodiment is merely an example, and various embodiments can be modified within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and the equivalent scope thereof.

2, 3 Reinforcing bar 10 Backing material 11 Bottom 12 Surface 13 End 21 Welding rod 22 Welding material G Gap

Claims (3)

Reinforcing bar welding backing material used when welding the rod-shaped ends of a pair of reinforcing bars.
At the time of welding, the reinforcing bar welding backing material having a U-shaped cross section that covers the reinforcing bars is used so that the bottom thereof covers a gap formed between the ends of the pair of facing reinforcing bars. ,
In order to observe the bottom portion through the gap and determine whether or not the welding material has been poured into the gap, it is composed of a ceramic material containing SiO ₂ and Al ₂ O ₃ as main components, and has a hunter whiteness of 59 or more . It is, rebar welding backing. The backing material for reinforcing bar welding according to claim 1, wherein the hunter whiteness is 70 or more. The backing material for reinforcing bar welding according to claim 1, wherein the content of _{Fe 2} O _{3 is 1.50 wt% or less.}

Images