JP3243588B2 - Back flux for single side welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backside flux for single-sided welding of a copper backing having a superior bead shape and preventing the welding backside flux from sticking to a copper plate in a single-sided welding of a copper backing.

[0002]

2. Description of the Related Art Single-sided welding of copper backing flux
As shown in FIG. 3, a back flux 4 scattered in a layer on the copper abutment 2 from the back surfaces of the welded materials 1, 1 a butted against each other.
To be welded 1, 1a by a lifting mechanism such as an air hose 5.
Is a welding method in which submerged arc welding is performed from the front side using the wire 3 and the front flux 6 from the front side, and beads are simultaneously formed on the front side and the back side of the material to be welded. In this welding method, the flux adheres to the back of the steel sheet, so the backing is in good contact. The copper bead under the flux suppresses the height of the back bead, so it is beautiful and sound even when using a large current. A good back bead is obtained. For this reason, it has been widely applied mainly to shipbuilding as a high-efficiency welding method for large plate joints.

In such a single-side welding method, Japanese Patent Publication No. 48-22572 and Japanese Patent Publication No. 49-31 are used for solidifying the back flux during welding in order to obtain a good back bead.
As disclosed in JP-B-417, JP-B-56-20960, and JP-B-61-13917, a back flux in which a thermosetting resin is adhered to a normal flux composition has been proposed.

However, if a back flux to which this kind of thermosetting resin is adhered is used, the solidified back flux that has been welded adheres to the copper alloy, requiring a great deal of labor to remove the back flux and greatly increasing the working efficiency. descend. The thermosetting resin is relatively low in temperature (80 to 90 ° C.) and is widely melted throughout the copper equivalent, so that the solidified back flux and peeling of the copper equivalent are significantly impaired.

Therefore, in order to prevent this sticking, as disclosed in Japanese Patent Publication No. 59-44958, etc., when a back flux is sprayed on a copper plate, a thermosetting resin first adheres. Sprinkle the unremoved powder to the lower layer,
Two-layer spraying has been proposed in which a back flux to which a thermosetting resin is adhered is sprayed thereon. However, it is very difficult to uniformly disperse the two layers of powder at an accurate height in large-plate joint welding with a welding length of 20 m or more. It is the current situation.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel back flux which prevents the welded back flux from sticking to copper in the above-mentioned single-sided flux copper backing method. is there.

[0007]

Means for Solving the Problems As a result of various studies in view of the above circumstances, the inventors of the present invention have found that, in the single-sided welding method of the copper backing flux, when the back flux is sprayed on the copper plate with a special spray truck. As shown in FIG. 1, it was observed that the coarse flux 4 was dispersed in the upper layer and the fine flux 4a was dispersed in the lower layer. In addition, in actual work, after pressing the back flux against the back surface of the steel sheet, in order to make the back flux and the back surface of the steel sheet more intimate, the vicinity of the groove from the front side of the steel sheet is hit with an iron lump, iron bar, etc. It is further promoted that the fine particles accumulate in the lower layer.

When the particle size of the fine particles is examined by two experiments, fine particles of less than 212 μm are 51% each,
This accounted for a very large proportion of 60%. Therefore, in order to measure the content of the thermosetting resin in the coarse-grained part and the fine-grained part, a back flux containing the thermosetting resin in 3.5% with respect to the total amount of the flux was manufactured, and an organic solvent extraction method was used. It was measured.

The organic solvent extraction method is a quantitative analysis method of a thermosetting resin as shown in the following procedure. Approximately 10 g of the back flux was precisely weighed, 20 ml of special grade ethanol was added, and the mixture was heated to near the boiling point, and then extracted under ultrasonic irradiation. Filter through 5C filter paper. This operation is repeated four times, and the combined filtrates are air-dried in a fume hood.

The weight of the separated and recovered thermosetting resin is measured. Using this organic solvent extraction method, particles of 212 μm or more and 2
As a result of measuring the content of the thermosetting resin in the particles having a particle size of less than 12 μm five times, it was found that the particles having a particle size of 212 μm or more had 3.1,
3.2, 2.9, 2.9, 3.1% average 3.0
% For particles less than 212 μm, 5.5,
5.1, 5.0, 6.8, 4.8% average 5.5
% And about 1.8 times the content. The particle size composition of this flux is such that 80%
20% of the particles were smaller than 2 μm.

[0011] This is because, when comparing the coarse-grained part and the fine-grained part with the same weight, the fine-grained part has a larger specific surface area. As a result, the content of the thermosetting resin adhering to the flux surface is reduced. It is thought to have increased. Therefore, it is considered that the main cause of the sticking is the thermosetting resin attached to the fine particles accumulated in the lower layer.

On the other hand, the thermosetting resin is melted by welding heat before welding is performed to solidify the flux, so that the flux adheres closely along the back surface shape of the steel sheet and is effective in obtaining a good back bead. It is. Therefore, a thermosetting resin is indispensable from the viewpoint of the formation of the back bead, and is absolutely necessary especially for the coarse-grained portion adhered to the back surface of the steel plate. That is, a thermosetting resin is necessary to form a good back bead, while on the other hand, in order to achieve the contradictory problem that it is unnecessary from the viewpoint of preventing the back flux from sticking to the copper equivalent, (1) The content of the thermosetting resin is divided into coarse-grained parts and fine-grained parts, and the content is specified. (2) Fine-grained parts that do not directly contribute to back bead formation are not necessarily thermosetting. It is not necessary to contain a resin; (3) it may be a mixed flux of a flux to which a thermosetting resin has adhered and a powder to which the thermosetting resin has not adhered; Comparing the particle size composition of the flux with the thermosetting resin attached and the particle size composition of the powder without the thermosetting resin attached,
Nominal size 850μm in JIS Z-8801 standard
No matter which of the following sieves is used,
It has been found that it is important that the weight of the flux to which the thermosetting resin adheres is larger than that of the powder to which the thermosetting resin does not adhere in the back flux remaining on the sieve surface.

That is, the gist of the present invention is as follows. (1) Flux Copper backing back flux for single-sided welding, wherein the back flux has a thermosetting resin adhered thereto.
Lux, particle size 212 μm by organic solvent extraction method
The content of the thermosetting resin in the back flux of up to 1.7 mm is 1.0 to 8.0% (% by weight, the same applies hereinafter) based on the total weight of the back flux having a particle size of 212 μm to 1.7 mm. The thermosetting resin content in the back flux having a particle size of less than 212 μm by an organic solvent extraction method is 212 μm
0.5% or less based on the total weight of the back flux having a particle size of less than 30 μm and a particle size of 212 μm to 1.7 mm.
Back flux for single-sided welding, characterized in that it contains 00% .

(2) Flux copper backing for one side welding
A back flux, a flux backing flux adhered thermosetting resin, granule thermosetting resin is not adhered Ri Na mixed, the particle size by organic solvent extraction process 2
Thermosetting in the back flux of 12 μm to 1.7 mm
When the resin content is less than
1.0-8.0% of the total weight of the organic solvent,
In the back flux having a particle size of less than 212 μm by the extraction method
Of thermosetting resin having a particle size of less than 212 μm
0.5% or less based on the total weight of
The flux to which the fat has adhered has a particle size of 212 μm to 1.7 mm.
30% to 100%, and a thermosetting resin
50 particles not having a particle size of 850 μm or less
A back flux for single-sided welding , characterized in that the flux contains about 100% .

The flux to which the thermosetting resin has adhered is SiO ₂ , CaO, MgO, CaF ₂ , Al ₂ O.
₃ , a molten flux mainly containing one or more of MnO, TiO ₂ , ZrO _2, etc., SiO ₂ , MgO,
CaCO ₃ , CaF ₂ , Al ₂ O ₃ , MnO, TiO ₂
And the like as a main component, and Si, M
n, Al, Ti, Mg, Ca, one or more alloys such as iron powder are added to a bond flux, and phenolic resin, furan resin, epoxy resin, urea resin, xylene resin, etc. The resin to be melt-cured is added and kneaded together with a solvent such as ethanol, methanol, or acetone, and then dried at a temperature lower than the melting temperature of the resin. In this case, regarding the addition of the resin and the solvent, any method may be used, whether the resin is previously added as a solution with a solvent and mixed, or the flux and the resin are mixed and the solvent is added to dissolve the resin. But it doesn't matter.

[0016] The powder and granules to which the thermosetting resin does not adhere are the molten flux used for the back flux,
Any type of bond flux or one or more of the main components of these fluxes may be used as long as they do not adversely affect the weld bead.

[0017]

Hereinafter, the present invention will be described in detail. When the back flux is sprayed on the copper metal, if the number of particles larger than 1.7 mm increases, voids between the particles increase, and the back bead is easily generated at the time of welding. Therefore, the back flux is 1.
It is desirable to be composed of particles of 7 mm or less. However,
From the viewpoint of productivity and the like, the effect of the present invention is not impaired even if some particles exceeding 1.7 mm are contained.

Therefore, in order to investigate the effect of the content of the thermosetting resin in the coarse portion and the fine portion of the back flux on the one-side welding method of the flux copper backing, a particle size of 212 μm to 1.
The amount of the thermosetting resin added to the flux composed of particles of 7 mm (hereinafter referred to as FA) and the flux composed of particles smaller than 212 μm (hereinafter referred to as FB) are respectively changed. In this way, back fluxes having different thermosetting resin contents were produced, and flux copper backing single-sided welding combining these was carried out. FIG. 2 shows the result.

As apparent from FIG. 2, the flux (F
When the content of the thermosetting resin of -A) is less than 1.0%, the degree of solidification of the flux is insufficient, and a back bead is easily generated.
Good bead formation became difficult. On the other hand, when the content of the thermosetting resin in the flux (FA) exceeded 8.0%, no reverse bead appeared. On the other hand, the flux (F
In the range where the content of the thermosetting resin of -B) exceeds 0.5%, sticking occurred to the copper equivalent. However, when the content of the thermosetting resin in the flux (FB) was 0.5% or less, the welded back flux did not adhere to the copper equivalent at all.

Therefore, the content of the thermosetting resin in the particles of 212 μm to 1.7 mm is set to 1.0 to 8.0%,
The content of the thermosetting resin in the particles having a particle diameter of less than μm was set to 0.5% or less. In FIG. 2, even if particles smaller than 212 μm do not contain a thermosetting resin, 212 μm to 1.7 mm
When the content of the thermosetting resin in the particles of the above is within the range of 1.0 to 8.0%, a good back bead can be formed, so that the flux to which the thermosetting resin adheres and the thermosetting resin The flux containing non-adhered powder was examined. In this case, the content of the thermosetting resin in the flux to which the thermosetting resin was attached was 1.0 to 8.0%.

As a result, it has been found that if there is a particulate material to which the thermosetting resin does not adhere, it is possible to prevent the solidified back flux from sticking to the copper alloy after welding. In this case, if it is 0.5%, there is no effect of preventing sticking, and if it exceeds 30%, the ratio of the back flux to which the thermosetting resin adheres becomes small, and the back bead is excessively generated. Therefore, it is desirable that the mixing ratio of the powder particles to which the thermosetting resin does not adhere is 0.5 to 30%. In addition, as a powder or granule to which the thermosetting resin is not attached, at least 21
It is desirable to contain fine particles of 2 μm or less.

The flux containing the thermosetting resin and the powder to which the thermosetting resin does not adhere is mixed, for example, the flux to which the thermosetting resin adheres and the thermosetting resin to adhere. Unmixed powders may be blended in a container and mechanically mixed by rotating stirring blades in the container or rotating the blended container itself.

Next, the particle size composition of the flux to which the thermosetting resin has adhered and the particle size composition of the powder to which the thermosetting resin has not adhered can be determined by using any sieve having a nominal size of 850 μm or less in JIS Z-8801 standard. Even if sieving is performed using, in the back flux remaining on the sieving surface, the weight of the flux to which the thermosetting resin is attached is larger than that of the powdery particles to which the thermosetting resin is not attached, that is, the thermosetting resin is The particle size composition of the adhered flux needs to be coarser than the particle size composition of the granular material to which the thermosetting resin does not adhere. That is, for the back flux shown in Table 1, the weight of the flux to which the thermosetting resin is attached and the weight of the powder to which the thermosetting resin is not attached are measured using, for example, a 212 μm sieve, and the former is (A + B + C + D + E) Gram, and the latter is (a + b + c + d + e) gram, and (A + B + C + D + E)> (a + b + c + d + e)
is necessary.

[0024]

[Table 1]

This is because, as described above, when the back flux is sprayed on the copper plate by the spray truck, the sprayed back flux 4, 4a has the coarse particles 4 in the upper layer as shown in FIG.
This is because the fine particles 4a are dispersed in the lower layer, and the particle size configuration of the flux to which the thermosetting resin is attached is coarser than the particle size configuration of the powder to which the thermosetting resin is not attached. The flux to which the thermosetting resin has adhered accumulates in the upper layer, and the powder particles to which the thermosetting resin does not adhere accumulate in the lower layer, and the thermosetting resin does not directly hit the copper plate during welding, causing the back flux to stick. Can be prevented.

Further, the particle diameter of the flux to which the thermosetting resin is adhered is 30 to 1 when the particle diameter is 212 μm to 1.7 mm.
Must be 00%. That is, if there are many particles finer than 212 μm, the flux is scattered to the lower layer when the copper is sprayed on the copper alloy, and not only the above-mentioned effect is not obtained, but also the solidifying power of the flux is reduced and a sound back bead shape is obtained. However, if the number of particles larger than 1.7 mm increases, as described above, when the back flux is sprayed, the gap between the particles increases, and the back bead increases during welding. From this, in order to form a good back bead, the particle diameter of the flux to which the thermosetting resin is attached is 212 μm to 1.7 m.
m must be 30% or more. Of course, these are 10
A particle size configuration of 0% may be used. For the above reasons, the flux having a thermosetting resin adhered thereto has a particle size exceeding 1.7 mm of 10% or less, and a flux of less than 212 μm has a particle size of 3% or less.
0% or less is desirable.

The particle size of the powder to which the thermosetting resin does not adhere must be 50% or more of fine particles of 850 μm or less. That is, particles coarser than 850 μm
If it is 0% or more, the flux is sprayed on the upper layer when it is sprayed on the copper metal, and not only the effect of preventing the back flux from sticking is obtained, but also the solidifying power of the flux is reduced, and a sound back bead shape is obtained. I can't get it. Of course, 850μ
A particle size configuration in which 100% of fine particles of m or less may be used. In this case, if it is 850 μm or less, an ultra fine powder which is usually called dust may be used. In addition, 30% or less of the coarse particles having a particle diameter of more than 850 μm of the powder particles to which the thermosetting resin does not adhere is desirable.

Although the present invention has been described in detail, examples will be described below to further clarify the effects of the present invention.

[0029]

EXAMPLE For the steel sheet shown in Table 2, the wires shown in Table 3 and Table 4 were used.
11 types of single-sided submerged arc welding were performed under the conditions shown in Table 5 using the table flux of Table 1. The flux in Table 4 was obtained by granulating the raw material powder using water glass,
Bonded flux fired in a rotary kiln under the conditions of ° C × 120 minutes, and the particle size of the finished flux is 12 × 1
The particles were sized with a 00 mesh. Table 6 shows the flux containing the thermosetting resin used for the back flux used for welding. In addition, in Table 5, the groove shape used the shape shown in FIG.

The back flux and welding results in the examples of the present invention are shown in Tables 7 and 8 (continued from Table 7). No. 1 of the present invention example. Nos. 1 to 7 were able to obtain good welding results due to the effects of the present invention. However, in Comparative Example No. In the case of No. 8, the bead shape was good,
The thermosetting resin content of fine particles of less than 0.5 μm is 0.5
%, The back flux stuck to the copper equivalent after welding.

Further, No. 9, 212 μm to 1.7
Since the content of the thermosetting resin in the coarse particles of mm exceeded 8.0%, no back bead was formed. No. In No. 10, 850 μm of the granules not containing the thermosetting resin
The particle size composition of the flux with few small particles and thermosetting resin attached is finer than the particle size composition of the powder without thermosetting resin attached. The attached flux accumulates in the lower layer,
The thermosetting resin directly hit the copper alloy, causing not only the back flux to stick, but also the particles without thermosetting resin to accumulate in the upper layer, and welding was performed with little resin. , A healthy bead could not be obtained.

Further, No. In No. 11, among the fluxes to which the thermosetting resin had adhered, the coarse particles of 212 μm to 1.7 mm were few, and the particle size composition of the flux to which the thermosetting resin had adhered was a powder or granular material to which the thermosetting resin did not adhere. The particle size becomes smaller than the particle size composition, and the flux to which the thermosetting resin adheres during the spraying of the flux accumulates in the lower layer, and the thermosetting resin directly hits the copper equivalent, causing not only sticking of the back flux but also heat. The powdery particles to which the curable resin did not adhere were accumulated in the upper layer, and welding was performed with little resin, so that a sound bead could not be obtained.

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

[Table 4]

[0036]

[Table 5]

[0037]

[Table 6]

[0038]

[Table 7]

[0039]

[Table 8]

[0040]

As demonstrated in the above examples, the flux of the present invention can provide excellent bead shape and good back flux peelability in one side welding of a copper backing flux, and greatly contributes to improvement of work efficiency on site. Things.

[Brief description of the drawings]

FIG. 1 is a front view showing a state of a back flux sprayed on a copper metal.

FIG. 2 is a diagram for explaining the effect of the thermosetting resin content of a coarse-grained part and a fine-grained part on one-side welding of a flux copper backing.

FIG. 3 is a front view for explaining a flux copper backing single-side welding method.

FIG. 4 is a front view showing a groove shape used in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Welded material 2 Copper equivalent 3 Electrode wire 4 Back flux (coarse grain) 4a Back flux (fine grain) 5 Air hose 6 Front flux t Plate thickness d Root face θ included angle

──────────────────────────────────────────────────の Continuation of the front page (72) Inventor Ryuichi Motomatsu 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (56) References JP-A-54-68744 (JP, A) JP-A-58-84675 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 35/362

Claims (2)

(57) [Claims] 1. A back flux for one side welding of a copper backing flux , wherein the back flux is provided with a thermosetting resin.
This is the flux that has adhered and has a particle size of 2 by the organic solvent extraction method.
The content of the thermosetting resin in the back flux of 12 μm to 1.7 mm is 1.0 to 8.0% (% by weight, hereinafter the same) based on the total weight of the back flux having a particle size of 212 μm to 1.7 mm. The thermosetting resin content in the back flux having a particle size of less than 212 μm by an organic solvent extraction method is
0.5% or less based on the total weight of the back flux having a particle size of less than 12 μm and a particle size of 212 μm to 1.7 mm
A back flux for single-sided welding, characterized by containing 0 to 100% . 2. A back foil for welding a copper backing on one side of a flux.
A Lux, the flux backing flux adhered thermosetting resin, Ri granular material thermosetting resin does not adhere the name mixed, the particle size by organic solvent extraction process 212
Thermosetting resin in the back flux of μm to 1.7 mm
Back flux with a content of 212 μm to 1.7 mm in particle size
1.0-8.0% of the total weight, extracted with organic solvent
In the back flux having a particle size of less than 212 μm by the method
Back flux having a curable resin content of less than 212 μm in particle size
0.5% or less based on the total weight of the thermosetting resin
The adhered flux has a particle size of 212 μm to 1.7 mm.
30% to 100%, and thermosetting resin adheres
The particles not having a particle size of 850 μm or less should be 50 to 1
Back flux for single-sided welding , characterized in that it contains 00% .