JPS5961595A - Backing strip for welding - Google Patents

Abstract

PURPOSE:To provide a backing strip for weldig of a solid flux compsn. having good bead formability such as uniformity, attachability, surface gloss, etc. of a bead by consisting the same of respectively specified ratios of SiO2, Al2O3 and MgO and specifying a range of apparent porosity. CONSTITUTION:A backing strip for welding consists of the solid flux having the compsn. limited to 45-70wt% SiO2, 15-40wt% Al2O3, and 5-30wt% MgO, and has 5-40% apparent porosity. If the solid flux having such compsn. is used, the part of the solid flux that contacts with a bead melts and forms slag 11 in the case of flat and horizontal one-side welding of a relatively low heat input. An adequate slag layer is thus formed together with the slag 10 formed from the wire itself whereby a penetration bead 8 is protected, and the uniform bead 8 having good attachment to the penetration bead and gloss is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a backing material for single-sided mark welding.

Conventional piece 1 weldable backing materials (hereinafter referred to as backing materials) include those made by solidifying flux, tape-shaped inorganic glass fibers, and cut glass fibers on solid slack. There is something arranged.

When single-sided welding was performed using these backing materials, each had the following drawbacks. First, conventional backing materials of the so-called solid flux type, which are made by solidifying and molding flux, have poor flexibility, so they do not adhere well to the back surface of the base material, and are particularly difficult to apply to uneven grooves or curved surfaces. In addition, this type of backing material has a high melting point to increase its fire resistance, so when applied to single-sided welding with relatively low heat input, such as downward or horizontal welding, the backing material will hardly melt. The conformability of the weld metal toe was poor, a back bead was not formed, and defects such as overlap were likely to occur, making it difficult to obtain a back bead weld with an excellent appearance.

- In contrast to backing materials made of inorganic glass fibers, both tape-like ones and those made by arranging glass fibers on solid flux, the surface of the backing material on the back of the base material is lower than that of solid flux-type backing materials. Although the adhesion to the glass fiber is good in terms of softness, since glass fiber usually contains several percent of B2O3, there is a problem in crack resistance. To solve this problem, backing materials using inorganic fibers that do not substantially contain B 203 have been devised, but in general, backing materials made of glass fibers are welded on one side with flux-cored wire. The slag formed by the filling flux and the slag formed by glass fiber melting,
A thick slag layer is formed between the base material and the backing material, resulting in an excess of slag, which often results in a lack of extra material on the backing bead or an undercut.

The present invention was made with the aim of solving the above-mentioned drawbacks of the back bead of conventional backing materials, and its gist is that the solid 7 lux composition is 5iQ224
5-70% by weight, Al2O3: 15-40% heavy end, Mg
O: 5 to -30% by weight, apparent porosity 5 to 40%
This is a true welding material characterized by the following.

The present invention will be explained in detail below.

First, the reason why the solid flux used in the present invention has the above composition will be described below.

As mentioned above, the role of solid flux in conventional painting materials is mainly as a fireproofing material5.Therefore, solid flux compositions are often highly fireproof with a melting point of 7000 or higher, and solid flux backing materials with this type of composition are used. When single-sided welding is performed, the conformability of the back bead is poor and a good back bead is difficult to form.

By the way, the present inventors have learned from various experiments that a solid flux having a composition that melts to some extent is good in so-called bead forming properties such as bead uniformity, bead conformability, and surface gloss.

In the present invention, based on the above knowledge, the solid flux composition is 5i02:45-70% by weight, AI! 203:
15 to 40% by weight, MgO: 5 to 30% by weight, and this range is sioz-A12oa-MgO.
In the system composition, the melting point is 135. It has the lowest OC of ~1500 tl:' and also has the role of a refractory material and a bead forming layer. That is, by using a solid flux having a composition within the above range, a relatively low heat input can be achieved.

Even in the case of horizontal single-sided welding, the part of the solid flux in contact with the bead melts and turns into slag 11 (Fig. 3), forming an appropriate slag layer with the slag lO generated from the wire itself to protect the back bead 8. It had good compatibility with the back bead, and a glossy and uniform back bead was obtained. If it is out of the above range, the melting point will be high and the fire resistance will be improved, but the solid flux will hardly be melted (as a result, the slab layer will be insufficient, the bead will not fit properly, and the back bead will be glossy and uniform). However, overlapping beads were obtained.

Next, in the present invention, the apparent porosity of the solid flux of the backing material is limited to 5 to 40%. The apparent porosity here refers to a value calculated using the following formula.

If the apparent porosity of the solid flux exceeds 40%, the bead may become too large and undercut may occur.
Furthermore, it is undesirable because workability deteriorates, such as frequent occurrence of spatter and narrowing of the range of welding conditions. Apparent porosity is 5%
In the following, a slag layer due to the solid flux is hardly formed, resulting in defects such as overlap and deterioration of the back beat shape.

Next, the measurement results of experimental examples and comparative examples of the present invention are shown in Table 1, and the effects of the present invention will be explained in more detail based on this table. The backing material of the example has a slab pocket 2 on the side in contact with the back surface of the groove of the base material 3 to be welded, as shown in FIG. The flux 1 was made into a tile shape and was continuously attached to an aluminum foil 4 having an adhesive part 5 to the steel material so as to be integrated.

Table 1 shows A12Al203- with a composition within the range of the present invention.
The configurations, welding conditions, and test results of the backing materials of the 8iQz-based experimental examples and comparative examples are shown at once. Cups 1 to 3 are experimental examples of the real backing materials, and A4 to A9 are the experimental examples of the backing materials. This is a comparative example that does not meet the constituent requirements of the backing material.

Flats 1 to A3, which are actual examples of the backing material, have good back bead shapes.

On the other hand, in case 4, where the apparent porosity of the solid flux is above the upper limit, the thermal conductivity of the backing material decreases and the amount of melting of the backing increases significantly, resulting in excessive back bead fxr).
A where undercut also occurs and the apparent porosity is below the lower limit
In contrast, in No. 5, there was almost no melting amount of the backing material, resulting in overlapping beads. Furthermore, in cases where the solid flux composition is in accordance with the present invention (A 6 to 8), the amount of backing melting is small (the backing bead is insufficient, the bead width and the bead size are uneven, In addition, the back bead with a good shape cannot be obtained due to overlap.71119, which uses a combination of glass tubes, not only lacks a back bead, but also has cracks on the bead.

As is clear from the explanation in Table 1 above (1) By using hair and this material that have a composition and apparent porosity within the range of the present invention, the shape of the goose bead is perfect and there is no overlap or undercut. The power of being able to give sufficient welding strength and an attractive appearance to the welded part is (1).

[Brief explanation of the drawing]

2.1 and 2 are schematic diagrams showing the structure of the inventive backing material, and FIG. 3 is an explanatory diagram showing the state after welding using the inventive backing material. 1...Solid flux 2...Slag pocket:
U... Base material to be welded 4... Aluminum foil 5...
Existing 1 agent 8...Uranami peed lO...Slag layer from wire J1...Slag melting part from solid flux. Representative Patent Attorney Masaaki Akizawa 2 Mitsugai (Koen) November 1, 1980 Patent Office, 11. , Government Hall 1, Middle School 1F'1 Large and Small Special 1B, '11'i 1984-171) t102
'Yow 2.36 Name of welding lifting material 3, supplementary table' 1 Relationship with soup 1 Application Person fi: Place (residence +17i) Otemachi 2, Chiyoda-ku, Kyoto
Ding l: I6, l? Mr. 3 V+ (Name) (”5
) Shin Nippon 3 Sokutetsu Co., Ltd. 4, Agent Hitoshi +iJi Chuo-ku, Tokyo 1, 1, 1, Taiyo Hill, 12, Chuo-ku, Tokyo −
1 (Shipping) 11$ Extinction'' A111.1 Force j11 6, No reason for invention to increase due to curved hole 7, Draw 1
1': (1) Q, J"4t Details 914. (Detailed explanation of ``Kuemei''): 4 \8, Inside the curved hole'et
Contents of the amendment as shown in the attached sheet 1 Mei 4 Hoshokyo, page 1, page 11, line 11: “One mark welded on one side”
"Single-sided arc welding" is corrected. 2. 4th line from the bottom of page 3 (correct ``-7 (1 (1'C or higher)'' to [171) 0℃ or higher''. 5

Claims (1)

[Claims] (1) Solid flux composition: 5iQ2: 45-70% by weight, Al2O3: 15-40% by weight, MgO: 5-3
0 weight:%, and the apparent porosity of the solid flux is 5~
A backing material for welding characterized by having a content of 40%.