JPH0117434Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a backing material used in gas-shielded metal arc welding with a narrow gap on one side. In butt welding of thick plates, a backing material is used to generate an arc between the wire and the workpiece, and a shielding gas such as argon or carbon dioxide is ejected around the weld. Gas-shielded metal arc welding is commonly performed. Conventionally, a strip-shaped steel material has been used as this backing material, but various materials have been developed in recent years from the viewpoint of workability. However, all of these were developed for V-shaped grooves, and they have low heat resistance, and when the root spacing is wide like an I-shaped groove, the backing material is directly exposed to arc heat and may melt through or the backing material may be exposed to arc heat. The drawback is that the wave beat becomes excessive. The present invention was devised in view of the above points, and provides an inexpensive backing material that can be sufficiently used for I-shaped single-sided narrow grooves by gas-shielded metal arc welding, and that can stably form a good uranami bead. Its unique feature is that both sides of the top surface of the band-shaped glass cloth are thickened to form a concave cross section, and a plate glass is attached to the back surface using double-sided adhesive tape. The present invention will be explained below with reference to FIGS. 1 to 3 of the embodiments. FIG. 10 is a diagram showing a cross section of the backing material 10 seen from the front or rear in the welding direction, in which 1a and 1b are glass cloth, 2 is a plate glass, and 3 is a double-sided adhesive tape. That is, a glass cloth having a concave cross-section with thicker sides of the upper surface is attached to the upper surface of the plate glass 2 using double-sided adhesive tape 3. In order to make the cross-section of the glass cloth concave, the width must be approximately 50 mm, for example. , the thickness is
A tape-shaped glass cloth 1b having a width of approximately 10 mm and a thickness of approximately 0.75 mm is sewn to both ends of the upper surface of a belt-shaped glass cloth 1a having a width of approximately 1.6 mm, thereby forming a concave cross section. Then, on the back side, a plate glass 2 with the same width as the glass cloth 1a and a thickness of about 5 mm is attached with double-sided adhesive tape 3.
Both ends are pasted. These glass cloths 1a and 1b are sheet-like sheets that are normally used for electrical insulation, and their chemical compositions are as shown in Table 1. Further, the plate glass 2 is an inexpensive soda glass that is generally used for window glasses and the like.

【table】

[Table] Figure 2 shows the backing material 10 constructed as described above.
It is a front view seen from the front in the welding direction, showing an example applied to a narrow groove. The objects to be welded 13, 13 are restrained by a restraining jig with appropriate route spacing, and a welding torch 11 equipped with a shielding gas nozzle 12 and a wire 15 is arranged in this groove. Then, the backing material 10 is attached to the groove of the concave copper pad 14 on the back side of the objects to be welded 13, 13 directly under the groove, and the object to be welded is
3 and 13 are pressed and fixed. Therefore, even if the dimensional accuracy between the objects 13 and 13 is somewhat poor, the plate glass 2 is fixed via the flexible glass cloths 1a and 1b, so the object 1 can be welded without being damaged.
3 and 13, and when welded, the glass cloths 1a and 1b have concave cross-sections, so that a sufficient back-wave bead is formed. Furthermore, since the backing material is composed of inorganic glass cloth and plate glass, it will not generate harmful gas even if it melts due to arc heat (the surface of the plate glass will melt, but the arc will not burn through). There are no problems with welding defects or pollution. Furthermore, by arranging a plate glass with a larger bulk specific gravity than glass cloth on the back surface, even if the surface of the plate glass melts during welding, the volume of the glass plate is small, so the excess buildup of the Uranami bead does not become large. Although the backing material of the present invention may be manufactured in advance to a certain length, it is wasteful if there are various objects to be welded and the welding length changes frequently.
Therefore, a method for simply manufacturing the above-mentioned backing material to any predetermined length will be explained with reference to FIG. 3. First, a tape-like glass cloth 1b is sewn onto both ends of the upper surface of a band-like glass cloth 1a (it may be stapled at arbitrary pitches) to form a concave shape, and a double-sided adhesive tape 3 is pasted on the back side of the tape-like glass cloth 1b. Wind it up to 4. Then, a band-shaped plate glass 2 of a certain length (for example, 1 m) is attached in advance to the back surface of the glass cloth 1a while winding the protective paper 6 of the double-sided adhesive tape 3 around the reel 5. If manufactured in this way, it is only necessary to attach as much plate glass as the welding length, which not only reduces waste but also makes the work extremely simple. As explained above, the backing material of the present invention is made of inorganic materials, so it has extremely high heat resistance, and can be fully used for gas shield metal arc welding of I-shaped narrow grooves, and does not generate harmful gases. A good Uranami bead can be formed. Furthermore, even if the surface of the plate glass is melted during welding, the volume of the glass plate is small, so that the extra layer of the uranami bead can be made to a necessary and sufficient size. In addition, since the constituent materials are inexpensive and manufacturing is simple, it is economical and has great practical effects. In the above embodiments, preferred materials and dimensions of the backing material have been described, but these can be appropriately determined depending on the dimensions of the object to be welded, mounting accuracy, welding conditions, etc., and are not particularly limited.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view showing an embodiment of the backing material according to the present invention, and Fig. 2 is a front view of this backing material applied to gas shield metal arc welding of an I-shaped narrow gap.
FIG. 3 is an explanatory diagram showing how to use the backing material of the present invention. 1a and 1b are glass cloth, 2 is plate glass, 3
is double-sided adhesive tape, 4 is a reel, 5 is a take-up reel, 6 is a protective paper, 10 is a backing material, 11 is a torch,
12 is a nozzle, 13 is a workpiece to be welded, 14 is a metal, 1
5 is a wire.

Claims (1)

[Scope of utility model registration request] A backing material for gas shield metal arc welding, characterized in that both sides of the upper surface of a band-shaped glass cloth are thickened to form a concave cross section, and a plate glass is attached to the back side with double-sided adhesive tape.