JP2002011594A - Flux-cored wire for gas shield metal-arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flux-cored wire for the gas shield metal-arc welding which can obtain the excellent bead shape and the excellent welding workability in a vertical welding position without increasing the sputter, etc., even when the aluminum oxide are added in the flux. SOLUTION: In the flux-cored wire for the gas shield metal-arc welding with the flux filled in a metal skin, the flux contains the raw titanium oxide with aluminum oxide added thereto, the raw titanium oxide contains 0.5-10 mass % aluminum oxide per total mass of the raw titanium oxide in terms of Al2O3. In the total amount of the flux, the titanium oxide and the aluminum oxide are contained at 4.5-9.0 mass % of the total mass of the wire in terms of TiO2, and at 0.05-1.5 mass % of the total mass of the wire in terms of Al2O3, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flux-cored wire for gas shielded arc welding in which a metal sheath is filled with a flux, and more particularly to a gas shield having a good standing bead shape and a good welding workability. The present invention relates to a flux cored wire for arc welding.

[0002]

_2. Description of the Related Art Conventionally, in flux cored wires for gas shielded arc welding for all positions containing a flux mainly composed of TiO ₂ , the fluidity of slag is adjusted to improve the bead shape in a vertical position. Al ₂ O ₃
And the like are added.

[0003]

However, the flux-cored wire for gas shielded arc welding increases the viscosity of the slag due to the addition of Al ₂ O ₃ and improves the bead shape in the upright posture, but the spatter is greatly reduced. There is a problem that increase is unavoidable.

The present invention has been made in view of such a problem, and even if aluminum oxide is added to a flux, an increase in spatter does not occur. An object of the present invention is to provide a flux-cored wire for gas shielded arc welding capable of obtaining excellent welding workability.

[0005]

The flux-cored wire for gas-shielded arc welding according to the present invention is a flux-cored wire for gas-shielded arc welding obtained by filling a metal sheath with a flux. Is added, and the titanium oxide raw material contains 0.5 to 10% by mass of aluminum oxide based on the total mass of the titanium oxide raw material in terms of Al ₂ O ₃ , In the total amount in the flux, titanium oxide is 4.5 to 9.0 mass% in terms of TiO ₂ per total mass of the wire, and aluminum oxide is A
It is characterized in that the content is 0.05 to 1.5% by mass based on the total mass of the wire in terms of l ₂ O ₃ .

In this case, in one or both of the metal sheath and the flux, Si:
0.1 to 1.2% by mass, Mn: 1.0 to 3.0% by mass, B: 0.001 to 0.025% by mass, Mg: 0.
1 to 0.8% by mass and metal fluoride: 0.0 in terms of F
It is preferable to contain 1 to 0.30% by mass.

The average particle diameter of the titanium oxide raw material to which the aluminum oxide is added is preferably 75 to 600 μm.

Further, it is preferable that the specific surface area of the titanium oxide raw material to which the aluminum oxide is added is 1.5 m ² / g or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present application have conducted intensive experiments and researches in order to solve the problems of the present invention. As a result, aluminum oxide was added as a flux component of a flux-cored wire for gas shielded arc welding. By containing the titanium oxide raw material, the aluminum oxide is uniformly dispersed in the flux, so that the viscosity of the slag is increased without deteriorating the welding workability, and the bead shape in the upright posture is improved. I found that. Also,
The aluminum oxide as a titanium oxide raw material to which the aluminum oxide is added increases the arc concentration, stabilizes the arc, reduces the amount of spatter generated, and increases the penetration depth.

Further, from the viewpoint of the impact performance of the weld metal, one or both of the metal sheath and the flux contain Si: 0.1 to 1.2% by mass and Mn:
1.0 to 3.0% by mass, B: 0.001 to 0.02
It is preferable to contain 5% by mass, 0.1 to 0.8% by mass of Mg and 0.01 to 0.30% by mass in terms of metal fluoride: F.

The reason for limiting the numerical value of the flux-cored wire for gas shielded arc welding according to the present invention will be described below.

Titanic acid added with aluminum oxide
Material: Total mass of titanium oxide material in terms of Al ₂ O ₃
Aluminum oxide (Al ₂ O ₃ ) is uniformly dispersed in the flux in an amount of 0.5 to 10% by mass. And added to the flux in the form added to. The aluminum oxide added to the titanium oxide raw material has the effect of increasing arc concentration, stabilizing the arc, reducing the amount of spatter generated, and increasing the penetration depth. The aluminum oxide content of the titanium oxide raw material to which aluminum oxide is added is Al ₂
O ₃ is less than 0.5% by mass of the total mass of the titanium oxide raw material in terms of small amount of Al ₂ O _3, because the slag viscosity hardly increases, exerts an effect of improving the bead shape in the vertical position Not done. On the other hand, if the content of aluminum oxide in the titanium oxide raw material to which aluminum oxide is added exceeds 10% by mass based on the total mass of the titanium oxide raw material in terms of Al ₂ O ₃ , the aluminum oxide absorbs moisture. Problems such as deterioration of the moisture absorption characteristics of the flux and an increase in the amount of water in the wire occur. Therefore, the titanium oxide raw material to which aluminum oxide is added is Al ₂
0.5 to 10 per total mass of titanium oxide in terms of O ₃
Contains aluminum oxide by mass.

Aluminum oxide: Total amount in flux
In terms of Al ₂ O ₃ , 0.05 to 1.
The content of 5 mass% aluminum oxide is A in the total amount in the flux.
If it is less than 0.05% by mass based on the total mass of the wire in terms of l ₂ O ₃ , the effect of improving the vertical bead shape due to an increase in the viscosity of the slag cannot be expected. On the other hand, when the content of the aluminum oxide exceeds 1.5% by mass in terms of Al ₂ O _{3 based} on the total mass of the wire in the flux, an increase in spatter and deterioration of slag removability due to hardening of the slag occur. . Therefore, the content of the aluminum oxide is set to 0.05 to 1.5% by mass based on the total mass of the wire in terms of Al ₂ O _{3 as} the total amount in the flux. In the present invention, in addition to the aluminum oxide added to the titanium oxide, it is also possible to independently add aluminum oxide to the flux. However, from the viewpoint of preventing the deterioration of welding workability, the content of the aluminum oxide supplementarily added alone is preferably 1.0% by mass or less based on the total mass of the wire in terms of Al ₂ O _{3 in} terms of the total amount in the flux. Is 0.
5 mass% or less. In any case, the content of the aluminum oxide must be 0.05 to 1.5% by mass based on the total mass of the wire in terms of Al ₂ O _{3 in} terms of the total amount in the flux.

Titanium oxide: Ti in total amount in flux
The content of titanium oxide of 4.5 to 9.0% by mass based on the total mass of the wire in terms of O ₂ is TiO ₂ in the total amount in the flux.
If the conversion is less than 4.5% by mass based on the total mass of the wire, the viscosity of the slag is insufficient, so that welding cannot be performed in a vertical position, the arc becomes unstable, and spatter increases.
On the other hand, when the content of titanium oxide is T
When iO ₂ exceeds 9.0 wt% based on the total mass of the wire in terms of problems such as the amount of oxygen in the weld metal is deteriorated impact performance of the weld metal increases occurs. In addition, the slag hardens and the slag releasability deteriorates remarkably, and spatter increases. Therefore, the content of titanium oxide is set to 4.5 to 9.0% by mass based on the total mass of the wire in terms of TiO _{2 in} terms of the total amount in the flux. In addition to the titanium oxide raw material in which aluminum oxide is added to the flux, it is also possible to separately add titanium oxide to which aluminum oxide is not added. However, also in this case, as described above, the content of the titanium oxide needs to be 4.5 to 9.0% by mass based on the total mass of the wire in terms of TiO ₂ in the flux.

As described above, the titanium oxide raw material to which the aluminum oxide is added used in the flux-cored wire for gas shielded arc welding according to the present invention has an aluminum oxide content of Al ₂ O in the total amount in the flux. It is 0.5 to 10% by mass based on the total mass of titanium oxide in terms of ₃ . As the titanium oxide raw material to which such an aluminum oxide is added, an industrially produced one used for a pigment or a paint can be used. These titanium oxide raw materials are generally used for improving lipophilicity.
The surface of the iO ₂ particles is coated with Al ₂ O ₃ , and the titanium oxide raw material contains several mass% of Al
Contains ₂ O ₃ . However, in these titanium oxide raw materials, TiO ₂ particles generally contain a few mass% of water, and therefore cannot be used as a raw material for a flux-cored wire as it is. Also,
Since these particles have a small particle size, the fluidity of the flux poses a problem in production. Therefore, in order to use these particles as a raw material for a flux-cored wire, drying, granulation,
Preliminary treatment of calcination and pulverization is preferably performed so that the average particle size is 75 to 600 μm and the specific surface area is 1.5 m ² / g or less. Further, in order to improve the dispersibility of Al ₂ O ₃ , it is preferable that the TiO ₂ particles serving as the raw material are as fine as possible.

FIG. 1 shows the form of existence of aluminum oxide.
FIG. _TwoA on the surface of the particles
l_TwoO_ThreeSectional view showing the raw material in which the layer is present, FIG._Two
O_ThreeTiO on the surface of the particles_TwoCross section showing raw material where layer exists
FIG. In addition, the above aluminum oxide is added.
Titanium oxide raw material is TiO for pigments_TwoTable of particles 1
Al on the surface_TwoO_ThreeLayer 2 but, conversely, Al_TwoO_ThreeGrain
TiO on the surface of element 3_TwoEven if layer 4 is present, the final Al_TwoO
_ThreeDoes not affect the dispersibility of Therefore, T
iO_TwoLayer 4 allows Al_TwoO_ThreeCoated with particles 3 of Al_Two
O_ThreeFor the wire with flux 3
The effect is the same even if it is used as a raw material.

Further, since Al ₂ O ₃ has higher hydrophilicity than TiO ₂ , as described above, the content of aluminum oxide as a titanium oxide raw material to which aluminum oxide is added, that is, TiO ₂ particles are reduced. When the content of the aluminum oxide to be coated exceeds 10% by mass based on the total mass of the titanium oxide raw material in terms of Al ₂ O ₃ , even if a pretreatment such as drying is performed, the moisture content of the wire increases due to re-absorption of particles. Problem arises.

Titanic acid to which aluminum oxide is added
Average particle size of the compound raw material: 75 to 600 μm After the pretreatment of firing and pulverization, if the average particle size of the titanium oxide raw material to which aluminum oxide is added is less than 75 μm, the fluidity of the flux becomes poor, Problems such as an unstable flux rate occur. On the other hand, when the average particle size of the titanium oxide raw material to which aluminum oxide is added exceeds 600 μm, the fluidity of the flux is ensured, but the titanium oxide raw material has a large particle size, and thus breaks during drawing. And other problems occur. Therefore, the average particle size of the titanium oxide raw material to which aluminum oxide is added is 7
The thickness is preferably 5 to 600 μm.

Titanic acid to which aluminum oxide is added
Specific surface area of compound raw material: 1.5 m ² / g or less When the specific surface area of the titanium oxide raw material to which aluminum oxide is added exceeds 1.5 m ² / g, the amount of moisture absorption increases, that is, Since the wire is deteriorated, the amount of moisture in the wire of the flux increases, which causes a problem that pore defects or low-temperature cracking occur during welding. Therefore, the specific surface area of the titanium oxide raw material to which aluminum oxide is added is preferably set to 1.5 m ² / g or less.

Si: 0.1 to 1.
2 mass% Si has the effect of adjusting the viscosity of the molten metal and improving the bead appearance and bead shape. Also, by adding Si appropriately, there is also an effect of reducing sputtering. However, the content of Si is set to 0.1 per the total mass of the wire.
If it is less than 1% by mass, the effect of improving the bead appearance and bead shape and the effect of reducing spatter cannot be obtained. On the other hand, the content of Si is 1.
If it exceeds 2% by mass, the strength of the weld metal will increase and impact performance will deteriorate. Therefore, the content of Si is preferably set to 0.1 to 1.2% by mass based on the total mass of the wire.

Mn: 1.0 to 3 per the total mass of the wire.
0 mass% Mn adjusts the viscosity of the molten metal similarly to Si to improve the bead appearance and bead shape, and promotes the deoxidation of the weld metal. In addition, a part of Mn is retained in the weld metal and becomes one component thereof, which has the effect of improving the hardenability, making the structure of the weld metal finer, and improving the impact performance of the weld metal. However, the content of Mn is 1.0 per total mass of the wire.
If it is less than mass%, the effect of improving the bead appearance and bead shape, deoxidizing the weld metal, and improving the impact performance of the weld metal cannot be obtained. On the other hand, when the content of Mn exceeds 3.0% by mass based on the total mass of the wire,
The strength of the weld metal increases and the impact performance deteriorates.
Therefore, the content of Mn is preferably set to 1.0 to 3.0% by mass based on the total mass of the wire.

The sources of addition of Si and Mn in the flux include electrolytic Mn, Fe-Mn, Fe-Si and Si.
-A Mn alloy or the like can be used.

B: 0.001 or more per total mass of the wire
0.025% by mass B has the effect of refining the structure of the weld metal and improving impact performance. B content is 0.00 per total mass of wire
If it is less than 1% by mass, there is no effect of refining the structure of the weld metal. On the other hand, the content of B is 0.02 per total mass of the wire.
If it exceeds 5% by mass, on the contrary, the structure of the weld metal becomes coarse, so that the impact performance of the weld metal deteriorates. Therefore, the content of B is 0.001 to 0.0025 per the total mass of the wire.
It is preferable to set it as mass%. As an addition source of B, there is an alloy such as Fe-B. In addition to the addition by the alloy such as Fe-B, the addition by B oxide is also possible. When B is added by B oxide, the B oxide is reduced to B during welding, and yields in the weld metal to become one component thereof.

Metal fluoride: F conversion per total mass of wire
In addition, 0.01 to 0.30% by mass of the metal fluoride has the effect of increasing the arc stability and reducing the amount of spatter generated, and also has the effect of reducing the amount of hydrogen in the weld metal and increasing the low-temperature crack resistance. These effects are exhibited by containing 0.01% by mass or more of metal fluoride in terms of F per the total mass of the wire. On the other hand, when the content of the metal fluoride exceeds 0.30% by mass in terms of F per the total mass of the wire, the amount of spatter and fume generation increases,
The fluidity of the slag becomes excessive and the bead shape deteriorates. Therefore, the content of the metal fluoride is preferably 0.01 to 0.30% by mass in terms of F per the total mass of the wire. In addition, as metal fluoride, Na, K, Li, M
Alkali metal and alkaline earth metal fluorides such as g and Ca are commonly used.

Mg: 0.1 to 0.1 per total mass of the wire.
8% by mass of Mg promotes deoxidation of the weld metal, reduces the amount of oxygen in the weld metal, and reduces B oxide or titanium oxide.
As a result, titanium and B yield in the weld metal, refine the structure of the weld metal, and improve the impact performance of the weld metal. This effect appears when the content of Mg is 0.1% by mass or more based on the total mass of the wire. On the other hand, when the content of Mg exceeds 0.8% by mass based on the total mass of the wire, deoxidation is not further promoted, and slag removability is deteriorated due to an increase in spatter and slag hardening. Therefore, Mg
Content is 0.1 to 0.8% by mass based on the total mass of the wire
It is preferable that

In the present invention, other alloy components can be added to the metal shell and / or the flux within a range satisfying the above requirements. For example, Ni, M
Since o, Cr and Cu do not particularly affect the effect of the present invention, they can be added as needed. As a deoxidizing agent, other than Si, Mn and Mg, T
i, Zr, Al, etc. can be added, but if the total amount of these elements exceeds 0.8% by mass with respect to the total mass of the wire, arc stability, bead appearance, bead shape, etc. will be deteriorated. Furthermore, oxides or carbonates of alkali metals such as K, Na and Li can be added as an arc stabilizer.

[0027]

EXAMPLES Examples of the flux-cored wire for gas shielded arc welding, which fall within the scope of the present invention, will be specifically described in comparison with comparative examples.

Flux-cored wires for gas shielded arc welding having the compositions shown in Tables 1 to 8 below were prepared.
The measurement methods for the items shown in Tables 1 to 8 below will be described.

For the measurement of titanium oxide, the flux is separated from the wire containing the titanium oxide, the flux is dissolved in alkali, the Ti is dissolved, and the solution in which unnecessary components are separated is quantified by redox titration to determine the metal content. Measure the amount of Ti,
This is converted to TiO ₂ . This TiO ₂ conversion value is defined as the amount of titanium oxide.

For the measurement of aluminum oxide, titanium oxide containing aluminum oxide is alkali-melted, and Al is dissolved.
The amount is determined and converted to Al ₂ O ₃ . This Al ₂ O ₃ conversion value is defined as the amount of aluminum oxide.

The average particle size of the titanium oxide raw material is determined according to JIS.
It was measured by a dry sieving test specified in Z8815. In addition, the specific surface area of the titanium oxide raw material is determined by measuring the amount of adsorption of N ₂ , and BET (Brunauer, Emmett and Teller)
Was calculated by the multipoint method.

Further, the amount of fluorine is determined according to JIS M8514.
It was measured by the method for quantifying the amount of fluorine specified in (fluorite for steel-analysis method).

Using the above-mentioned wires, welding was performed under the welding conditions shown in Table 9 below, and welding workability (bead shape, spatter generation state and arc concentration in vertical welding) was evaluated. The results are shown in Tables 10 and 11. Hereinafter, the evaluation method and evaluation criteria of the welding workability will be described.

The bead shape was evaluated by sensory evaluation.
The evaluation was ◎ (extremely good) when the bead surface was almost completely flat (flat), ○ (good) when the bead surface was almost flat (flat), and the bead surface was slightly convex. The state was evaluated as Δ (slightly poor), and the state where the bead surface was convex was evaluated as × (defective).

The amount of spatter generated was evaluated by sensory evaluation. The evaluation was ◎ (extremely good) when the particle size of the spatter was small and the amount of generation was small, and ○ (good) when the particle size of the spatter was slightly large but the amount was small.若干 (somewhat bad)
And those with large spatter particle size and large amount of generation
(Poor).

Further, the arc concentration was evaluated by sensory evaluation. The evaluation was evaluated as ◎ (very good) when the spread of the arc was small and the penetration was deep, and the evaluation was 良好 (very good).
(Good), and the arc with a large spread and a slight penetration feel was rated as △ (somewhat poor).

Further, regarding the wire hygroscopicity, a wire having a water moisture content of 700 mass ppm or more after being left for 1 week in an atmosphere at a temperature of 30 ° C. and a relative humidity of 80% was rated as Δ. The flux fluidity was evaluated as “△” when the flux flow was poor and the flux rate was not stable in wire production. Further, those having broken wires during wire production were expressed as "poor wire drawability" in the "Other properties" column of Tables 10 and 11.

In Table 2, "≤0.1" is 0.1
Indicates that: In the columns of other alloy components in Tables 3 and 7, the left side shows the substance names of the other alloy components, and the numerical values on the right side show the content per the total mass of the wire. Also in the column of other deoxidizers, the left side shows the substance names of other deoxidizers, and the numerical value on the right side shows the content per the total mass of the wire. In Tables 3 and 7, "-" indicates that it was not added. Table 4
In the column of the amount of fluoride in Table 8, the left-hand side shows the substance name of the fluoride, and the numerical value on the right-hand side shows the content per the total mass of the wire. Furthermore, the amount of F is determined by converting fluoride to F
The arc stabilizer is defined as Na ₂ O, K ₂
O and Li ₂ O, and the slag forming agents are SiO ₂ , Z
rO ₂ and MgO, the balance being Fe and others.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

[Table 5]

[0044]

[Table 6]

[0045]

[Table 7]

[0046]

[Table 8]

[0047]

[Table 9]

[0048]

[Table 10]

[0049]

[Table 11]

As shown in Table 10, in Examples Nos. 1 to 15, good results were obtained with respect to the bead shape in the upright posture, the spatter generation state, and the arc concentration. Example No. 9 satisfies claim 1, but the amount of other Al ₂ O ₃ exceeds the upper limit of the present invention, so that the spatter generation was slightly inferior.

Although Example No. 10 satisfies claim 1, the drawability is slightly inferior since the average particle size of the titanium oxide raw material to which aluminum oxide is added exceeds the upper limit of the present invention. . Although Example No. 11 satisfies claim 1, the average particle diameter of the titanium oxide raw material to which aluminum oxide is added is less than the lower limit of the present invention, and the titanium oxide raw material to which aluminum oxide is added. Since the specific surface area exceeds the upper limit of the present invention, the flux fluidity and the wire hygroscopicity were slightly inferior.

Although Example No. 12 satisfies claim 1, the content of Si contained in the shell and / or the flux exceeds the upper limit of the present invention, and the content of Mg is lower than the lower limit of the present invention. However, since these deteriorate the impact property of the weld metal, there was no influence on the welding workability, and good results were obtained in the bead shape, spatter generation state and arc concentration in the upright posture. Example No. 1
No. 3 satisfies claim 1, but the content of Mn and Mg contained in the outer skin and / or the flux exceeds the upper limit of the present invention, and the content of B is lower than the lower limit of the present invention. The outbreak was slightly inferior. Example No. 14 satisfied claim 1, however, since the contents of Si, Mn, and B contained in the shell and / or the flux were less than the lower limits of the present invention, spatter generation was slightly inferior.

Example No. 15 satisfies claim 1, but the flux fluidity was slightly inferior because the average particle size of the titanium oxide raw material to which aluminum oxide was added was less than the lower limit of the present invention. . Although Example No. 16 satisfied Claim 1, the specific surface area of the titanium oxide raw material to which aluminum oxide was added exceeded the upper limit of the present invention, so that the wire hygroscopicity was slightly inferior. Example No. 17 satisfied Claim 1, but the amount of metal fluoride in terms of F was less than the lower limit of the present invention, so that the spatter generation was slightly inferior. Although Example No. 18 satisfied Claim 1, the amount of metal fluoride in terms of F exceeded the upper limit of the present invention, so that the spatter generation was slightly inferior, and the amount of fume generated was slightly large. Although Example No. 19 satisfies Claim 1, the average particle size of the titanium oxide raw material to which aluminum oxide is added is less than the lower limit of the present invention, and the specific surface area exceeds the upper limit of the present invention. And Si, Mn, B, Mg
In addition, since the F conversion amount of the metal fluoride was out of the proper range, the spatter generation state and arc concentration were slightly inferior. Also, the amount of fume generation was slightly higher.

On the other hand, as shown in Table 11 above, Comparative Example N
In the case of o.20, the wire hygroscopic property was not possible because the amount of aluminum oxide in terms of Al ₂ O ₃ in the titanium oxide raw material to which aluminum oxide was added exceeded the upper limit of the present invention. Comparative Example No. 21 shows the total TiO ₂ per the total mass of the wire.
Since the amount exceeded the upper limit of the present invention, the state of occurrence of spatter was inferior. Also, the impact performance deteriorated. Comparative example No.2
In No. ₂ , since the total amount of TiO ₂ per the total mass of the wire was less than the lower limit of the present invention, the bead shape in the upright posture was inferior, and the spatter generation was slightly inferior. In Comparative Example No. 23, since the total amount of Al ₂ O ₃ per the total mass of the wire exceeded the upper limit of the present invention, the spatter increased and the spatter generation was inferior. Comparative Example No. 24 shows the total Al ₂ per wire total mass.
Since the O ₃ amount was less than the lower limit of the present invention, the bead shape and arc concentration in the upright posture were slightly inferior. In Comparative Example No. 25, the amount of aluminum oxide in terms of Al ₂ O ₃ in the titanium oxide raw material to which aluminum oxide was added was less than the lower limit of the present invention. Was also slightly inferior.

[0055]

As described in detail above, according to the present invention, the content of aluminum oxide contained in titanium oxide,
Since the content of titanium oxide and the content of aluminum oxide, including the aluminum oxide contained in titanium oxide, are appropriately specified, spatter increases even if aluminum oxide is added to the flux. , And a good bead shape and good welding workability can be obtained in a vertical welding posture.

[Brief description of the drawings]

[1] A sectional view showing an existing form of aluminum oxide, (a) shows the cross-sectional view showing a raw material there are the Al ₂ O ₃ layer on the surface of the TiO ₂ particles, (b) is Al ₂ O FIG. 4 is a cross-sectional view showing a raw material in which a TiO ₂ layer exists on the surface of particles ₃ ;

[Explanation of symbols]

1,3; particles 2; Al ₂ O ₃ layer 4; TiO ₂ layers

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kawa ▲ saki ▼ Hiroyuki 100-1 Urakawachi, Miyamae, Fujisawa-shi, Kanagawa F-term in Kobe Steel, Ltd. Fujisawa Plant F-term (reference) 4E084 AA02 AA07 AA17 BA03 BA04 BA12 BA18 CA23 CA24 DA10 FA03

Claims (4)

[Claims] 1. A flux cored wire for gas shielded arc welding comprising a metal sheath filled with a flux, wherein the flux contains a titanium oxide raw material to which aluminum oxide is added. 0.5 in total weight of titanium oxide raw material in terms of Al ₂ O ₃
About 10% by mass of aluminum oxide, and in the total amount of the flux, titanium oxide is Ti
A gas characterized by containing 4.5 to 9.0% by mass per total mass of wire in terms of O _{2 and} 0.05 to 1.5% by mass of aluminum oxide per total mass of wire in terms of Al ₂ O _3. Flux-cored wire for shield arc welding. 2. In one or both of the metal sheath and the flux, Si: 0.1 to 1.2% by mass, Mn: 1.0 to 3.0% by mass, B:
2. The composition according to claim 1, wherein the composition contains 0.001 to 0.025% by mass, Mg: 0.1 to 0.8% by mass, and metal fluoride: 0.01 to 0.30% by mass in terms of F. The flux-cored wire for gas shielded arc welding according to the above. 3. The flux cored wire for gas shielded arc welding according to claim 1, wherein the titanium oxide raw material to which the aluminum oxide is added has an average particle size of 75 to 600 μm. 4. The gas shield according to claim 1, wherein a specific surface area of the titanium oxide raw material to which the aluminum oxide is added is 1.5 m ² / g or less. Flux-cored wire for arc welding.