JP3288535B2 - Flux-cored wire for gas shielded arc welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of steel structures such as shipbuilding, steel frames, bridges, etc., and is particularly applicable to automatic horizontal fillet welding of thick plates. The present invention relates to a flux-cored wire for gas shielded arc welding (hereinafter, referred to as a flux-cored wire) from which leg length beads can be obtained.

[0002]

2. Description of the Related Art In recent years, flux-cored wires of various types, such as those for welding in all positions and those for horizontal fillet welding, which meet the requirements of each construction site, have been widely used for manufacturing various structures. This is because of the advantages of flux-cored wire, such as the ability to weld in a stable arc state with little spatter due to the action of the filling flux, excellent bead shape and appearance, and high wire melting speed and high efficiency at the same current. This is because it meets the requirements of the construction site. Recently, there has been a demand for the development of a flux-cored wire having an unprecedented welding performance for higher efficiency and labor saving. One of them is a flux cored wire for horizontal fillet welding of thick plates from fields such as shipbuilding, steel frames and bridges. This is to perform horizontal fillet welding with a leg length of 8 mm or more by one-pass welding or a leg length of about 15 mm by two-pass welding. Conventionally commercially available rutile type for all positions or horizontal fillet In the case of the flux-cored wire, if the leg length exceeds approximately 7 mm by one-pass welding, a cut is generated in the standing plate, the bead toe wraps, resulting in a poor shape, and a bead having a lower part cannot be obtained to obtain a required leg length.

On the other hand, Japanese Patent Application Laid-Open No. Hei 4-300091 proposes a flux-cored wire obtained by one-pass welding of a horizontal fillet bead having a leg length of 8 to 10 mm. However, there are problems in horizontal fillet welding of thick plates, regardless of one-pass welding or two-pass welding, as well as bead forming properties for obtaining a good bead shape and appearance with a large leg length and increasing the weld length with an increase in leg length. Slag entrainment, which is likely to occur, and insufficient penetration at the corners of the standing plate and the lower plate. This tendency of occurrence of welding defects is more remarkable in the case of automatic welding by a simple traveling cart or a robot than in the case of semi-automatic welding.

[0004]

Therefore, the present invention is applied to automatic horizontal fillet welding of a thick plate, and it has good bead shape and appearance, and defects such as slag entrainment and insufficient penetration occur in a welded portion. An object of the present invention is to provide a flux-cored wire for gas shield arc welding that is difficult to perform.

[0005]

That is, the gist of the present invention is as follows.
(1) A flux-cored wire for gas shielded arc welding in which a flux is filled in a steel sheath, and the following components are essential as to the total weight of the wire;
And (2) a flux-cored wire for gas shielded arc welding, further comprising 0.1 to 1.0% by weight of Ni. TiO _2: 4.5 to 7.5 wt% SiO _2: 2.1 ~3.0 wt% MgO: 0.5 to 3.0 wt% ZrO _2: 0.5 to 2.0 wt% Al ₂ O ₃ : 0.1 to 1.0% by weight, provided that SiO ₂ / (TiO ₂ + SiO ₂ + MgO + Zr
O ₂ + Al ₂ O ₃ ): 0.16 to 0.25 Iron oxide: 0.3 to 1.5% by weight F: 0.03 to 0.35% by weight One or more of Na, K, and Li Total: 0.05
-0.35% by weight Deoxidizing agent (including the outer skin component): 1.5-5.0% by weight

[0006]

First, the present inventors prototyped flux-cored wires of various compositions for the purpose of preventing slag entrapment and insufficient penetration of corners, which are problems in welding a horizontal fillet with a long leg. , And carefully observed the welding condition. FIG. 1A shows a target position of a wire tip and a welding state when a long leg bead is formed by one-pass welding and two-pass welding. As shown in the drawing, the tip of the wire 1 is aimed at a distance (L ₁ , L ₂ ) commensurate with the target leg length (1) of the bead 5 from the corner 4 between the standing plate 2 and the lower plate 3. Leg length 1 especially in 2-pass welding
When obtaining a large leg length of 3 to 15 mm, target position L ₂ of the first pass of the wire tip 6~7m corner portion
m must also be separated. At this time, leg length (welding amount)
The welding pool is relatively large because welding is performed with a high current and a low welding speed in order to ensure that the wire length is relatively large. Since the arc does not easily hit the corner directly, the arc does not have the effect of digging down the base material, which causes insufficient penetration.

In this type of flux-cored wire for a long leg, a slag forming agent is used in order to obtain a good bead shape and appearance, and MgO, ZrO ₂ , A
It is necessary to contain a high melting point oxide such as l ₂ O ₃ as a wire composition in a considerable amount. The solidification of the molten slag becomes faster as the composition of the wire contains more of these high melting point oxides, and the target position of the wire fluctuates due to vibration during the running of the welding equipment and the gap between the standing plate and the lower plate, resulting in an arc state. It was found that the slag floating from the molten pool was not smoothly performed when it changed, and slag entrainment was likely to occur.

[0008] Further, the above-mentioned tendency of occurrence of welding defects is caused by melting.
Look at the pool condition and aim and move the welding speed and wire tip.
Semi-automatic operation while freely adjusting the rod (oscillate) etc.
Performing under certain welding conditions pre-input rather than welding
It increases in the case of automatic welding. This is a long leg
In the case of fillet welding, the target position of the wire tip is
2 (a),
Torch angle θ shown in (b) _T(Wire elevation) and wire
Progress angle θ_W(Easily affected by full advance and reverse angles)
This is due to the fact that it cannot be covered under force conditions. For example, a robot
3. Winding of the end of the horizontal fillet welding member as shown in FIG.
When the welding part 6 is also performed continuously, in the vicinity of the end of the welding member,
To maintain good fit at the bottom of the bead, adjust the torch angle and
Welding while changing the wire advance angle.
You. At this time, especially the wire elevation angle θ_TMay be larger
In the welded portion welded at the advancing angle
Slag entrapment and insufficient penetration at corners
Increase.

In the case where the welding member has a complicated structure and the side plate 8 for hindering the advance of the torch is attached, FIG.
As shown therein, the region I is a portion where the wire advance angle θ _W can be set to a right angle or a receding angle, the region II is a portion where a forward angle is required, and the region III is a torch angle θ _T and a wire advance angle θ _W.
Can be broadly divided into the parts to be welded. In other words, the wire advancing angle θ _W in the immediate vicinity of the side plate is 2
There is a street. It is preferable that the flux-cored wire can be sufficiently applied to various cases. In addition,
Generating slag entrainment when the wire elevation theta _T is too small are those which solidified while molten slag is pushed in the corner portion, also penetration shortage inclusive corners when the receding angle was too large by the arc force It is likely to occur when the molten metal is blown backward and the bead shape becomes convex, and these are within the range that can be prevented by changing the welding conditions.

Next, the present inventors have studied in detail the wire composition that can prevent the occurrence of the above-mentioned welding defects based on good bead forming property in the automatic horizontal fillet welding with a long leg. As a result, the slag forming agent contained in the wire is reduced to T
iO ₂ -SiO ₂ and -MgO-ZrO ₂ -Al ₂ O ₃ system, particularly the solidification temperature of the molten slag in the case of changing the content of SiO _2, the penetration of the viscous and flowable slag inclusion and corners Investigating the wire composition, paying attention to the large effect, and finding that adding a small amount of Ni improves the compatibility between the molten metal and the base material and is effective in improving the penetration at the corners. Thus, the present invention has been completed.

Hereinafter, the reasons for the construction of the present invention will be described in detail. TiO _2: 4.5 to 7.5 wt% TiO ₂ as a major component of the slag-forming agent, uniformly encapsulated with the bead shape of the entire bead, to be contained in order to adjust the appearance. In addition, it has an effect of sustaining and stabilizing the arc. If TiO ₂ is less than 4.5% by weight, the amount of slag generated is insufficient, the slag encapsulation is not sufficient, and a good bead shape is obtained.
The appearance cannot be obtained, and the occurrence of spatters increases. On the other hand, if TiO ₂ exceeds 7.5% by weight, the amount of slag generated becomes excessive, and slag entrainment is likely to occur.

SiO ₂ : 2.1 to 3.0% by weight SiO ₂ contains a high melting point oxide such as MgO, ZrO ₂ or Al ₂ O ₃ as an essential component. To adjust liquidity
2.1 % by weight or more. 2.1 % by weight of SiO ₂
If it is less than 30%, slag entrapment and insufficient penetration of corners are liable to occur. On the other hand, if it exceeds 3.0% by weight, the solidification temperature of the molten slag decreases and fluidity becomes excessive. Cuts are likely to occur on the uprights.

MgO: 0.5 to 3.0% by weight MgO is contained for improving bead forming properties.
When a conventional rutile flux-cored wire for all postures is used for horizontal fillet welding of a long leg, cutting of the standing plate becomes a problem as well as laps at the bead toe and insufficient leg length on the standing plate side. By containing an appropriate amount of MgO, the solidification temperature is high, and a molten slag having low viscosity and high fluidity in a high-temperature region immediately before solidification is obtained, so that melting of the standing plate can be suppressed and generation of cuts can be prevented. Further, since the molten slag starts to solidify thickly along the bead toe, the molten metal is blocked and a good bead shape that does not wrap is obtained. Also on the standing plate side, the solidification of the molten slag starts quickly, so that the slag encapsulation is good and the flow of the molten metal is suppressed, so that the leg length can be secured. If the content of MgO is less than 0.5% by weight, cuts occur in the standing plate, and it is not possible to form a long leg bead with equal legs. On the other hand, if it exceeds 3.0% by weight, slag solidification unevenness occurs on the bead surface, and bead shape and appearance are deteriorated, and slag entrainment is liable to occur.

ZrO ₂ : 0.5 to 2.0% by weight ZrO ₂ adjusts the viscosity and fluidity of the molten slag and adjusts the bead shape to an equal length. In particular, it has the effect of smoothing the bead surface and improving the appearance. There is. If ZrO ₂ is less than 0.5% by weight, the slag encapsulation property is not sufficient, and the bead shape and appearance deteriorate. On the other hand, if ZrO ₂ exceeds 2.0% by weight, the bead shape is rounded, and the slag removability deteriorates.

Al ₂ O ₃ : 0.1 to 1.0% by weight In the present invention, Al ₂ O ₃ is an essential component for improving slag removability, in addition to adjusting viscosity and fluidity of molten slag. To be contained. 0.1% by weight of Al ₂ O ₃
If less than 1.0, no effect of improving slag removability is observed,
If the content is more than 10% by weight, the bead becomes convex and the shape deteriorates. SiO ₂ / (TiO ₂ + SiO ₂ + MgO + ZrO ₂ +
Al ₂ O ₃ ): 0.16-0.25

According to the present invention, TiO ₂ , Si
O ₂ , MgO, ZrO ₂ , and Al ₂ O ₃ are contained as slag-forming agents in a limited range, respectively. In particular, the present invention aims to reduce slag entrapment and insufficient penetration of corners in a large leg-length horizontal fillet bead. In order to prevent the generation, it is essential to increase the ratio of SiO _{2 to} the total content of these slag forming components to 0.16 or more. At this time, the generation of the molten slag having a small viscosity and high fluidity expands the exposed surface of the molten pool and facilitates the floating of the molten slag, which is effective in preventing slag entrainment. Furthermore, the molten pool, which is easily blown toward the corner by the arc force, comes into contact with the corner and works effectively against penetration.

FIG. 4 is a graph showing the relationship between S and S for the slag forming agents shown in Table 1.
Using a flux-cored wire (wire diameter 1.4 mm) with a varied iO ₂ ratio, horizontal fillet welding with a plate thickness of 16 mm (target leg length 10 mm by one-pass welding, 360A-36)
V-25 cm / min, distance between tip base materials 25 mm, wire elevation angle 50 ° -advance angle 25 °, shielding gas CO ₂ 2
5 shows the results of an experiment on the tendency of occurrence of the above welding defects when performing 5 L / min), but the above internal welding defects did not occur when the ratio of SiO ₂ was 0.16 or more. . On the other hand, when the ratio of SiO _{2 to} the total content of the slag forming agent component exceeds 0.25, the cut of the upright plate and the wrap at the bead toe portion are conspicuous, and the bead shape is deteriorated.

Iron oxide: 0.3 to 1.5% by weight Iron oxide also adjusts the viscosity and fluidity of the molten slag and effectively acts on bead formation, but is particularly effective in improving the uniformity of the bead toe. It is. To obtain this effect, FeO, Fe ₂
0.3 to 1.5% by weight of iron oxide such as O _{3 is} contained. If the iron oxide content is less than 0.3% by weight, the affinity with the lower plate is poor, and the bead toe portions are not uniform. On the other hand, if it exceeds 1.5% by weight, the fluidity of the slag becomes excessive, the leg length on the standing plate side is insufficient, and the toe becomes a wrapped bead. In addition, the slag on the standing plate side of the bead becomes thin, and the slag is seized in high current welding for obtaining a long leg long bead, making it difficult to remove the slag.

F: 0.03 to 0.35% by weight F is added to adjust the viscosity and fluidity of the molten slag and to improve the primer resistance of a primer-coated steel sheet frequently used in the field of shipbuilding and bridges. If the effect of F is less than 0.03% by weight, the effect cannot be exerted. In particular, the occurrence of blow holes that deteriorate the mechanical properties of the welded portion and pits that require rework and reduce the welding efficiency poses a problem. on the other hand,
If it exceeds 0.35% by weight, the fluidity of the molten slag becomes excessive and the leg length on the standing plate side cannot be secured. In addition, the slag encapsulation property is insufficient, and slag peeling and bead appearance become poor. Further, the spread of the arc is reduced and the molten pool is reduced, which causes slag entrainment and insufficient penetration at the corners. Li, K, Na, as raw materials for containing F,
Metal fluorides such as Mg, Ca, and Al can be used.

One or more of Na, K and Li: 0.05 to 0.35% by weight Na, K and Li are contained as an arc stabilizer. The total of one or more of these alkali metals is 0.05
If the amount is less than the weight percentage, the arc becomes coarse and the generation of spatters increases. On the other hand, when the content exceeds 0.35% by weight, the arc state becomes unstable, the molten pool swings violently, and slag entrainment and insufficient penetration of corners are likely to occur.

Deoxidizing agent (including a skin component): 1.5 to 5.
0% by weight C (0.01-0.10% by weight), Si (0.3-2.
0% by weight), Mn (0.5 to 4.0% by weight), Ti
(0.5% by weight or less), Al (1.0% by weight or less), M
g (1.0% by weight or less) and a deoxidizing agent such as Zr (0.5% by weight or less) in order to secure the mechanical properties of the welded portion and to prevent the occurrence of porosity in the welded portion due to insufficient deoxidation. 1.5% by weight or more in total. On the other hand, if the deoxidizing agent is contained in excess of 5.0% by weight, the strength becomes too high and the bead crack resistance is reduced. Since the deoxidizing agent not only works as a yield alloying agent in the weld metal but also slags and affects the composition and production amount of the molten slag, it is preferable that the above-mentioned components be suppressed within the range in parentheses.

Ni: 0.10 to 1.0% by weight or more is a basic constitution of the present invention. By further containing Ni in an amount of 0.10% by weight or more, it is evident that the penetration of corners is improved. The effect is recognized. This effect is considered to be because the molten metal containing Ni improves the compatibility with the steel sheet. The upper limit of Ni is set to 1.0% by weight in consideration of the crack resistance of the bead and the production cost. In addition, in the case of using a flux-cored wire to which a small amount of Ni shown in Table 1 was added in FIG.
₂ ).

[0023]

[Table 1]

As another component of the flux-cored wire used in the present invention, an iron powder (10% by weight or less) which is effective for increasing the welding amount, improving the arc state and reducing spatter, based on the total weight of the wire. ), Mo (1.0% by weight or less), Cr (1.0% by weight or less), Cu (0.5% by weight or less) to improve the mechanical properties, weather resistance and fire resistance of the weld metal.
Wt% or less), B (0.010 wt% or less), various alloying elements, metal carbonates such as CaCO ₃ (0.5 wt% or less) to stir the molten pool and improve primer resistance, further slag removal Bi (0.5
% By weight or less).

Regarding the shell metal of the flux-cored wire, mild steel (C: 0.08% by weight or less, Si: 0.3% by weight or less, Mn: 0.5% by weight or less, P: 0) from the viewpoint of wire productivity. 0.020% by weight or less, S: 0.020% by weight
The following is preferred, but alloy steel (C:
0.07% by weight or less, Si: 0.3 to 1.5% by weight, M
n: 0.5 to 2.5% by weight, P: 0.020% by weight or less, S: 0.020% by weight or less, and Al and Ti: 1.0% by weight or less.

The flux filling rate is 1 to the total weight of the wire.
The range of 2 to 25% by weight is preferable from the viewpoints of securing the amount of slag generation and leg length and wire productivity. There is no particular limitation on the cross-sectional shape of the wire, and a conventional general shape as shown in FIG. 5 may be used. The seamless type (a) having no opening in the outer skin portion 9 has no moisture absorption of the flux 10 and has primer resistance. It is most suitable as a wire for automatic welding of robots and the like because it does not impair the wire feeding property and is excellent in wire feeding property and stability of the target position of the wire tip. Although the wire diameter is not particularly limited, it is necessary to increase the size of the molten pool and perform welding in order to prevent welding defects of the long leg bead as described above. The shielding gas is generally a CO ₂ gas, but the effect of the present invention can be obtained even when an Ar—CO ₂ based gas is used.

Hereinafter, the effects of the present invention will be specifically described with reference to examples.

EXAMPLE Mild steel pipe (C: 0.05% by weight, Si:
0.02% by weight, Mn: 0.25% by weight, P: 0.01
2% by weight, S: 0.004% by weight, and Al: 0.01% by weight), and wires having the compositions shown in Tables 2 and 3 were prototyped by a conventional method. The flux filling rate of the prototype wire is 18% by weight, and the wire diameter is 1.4 mm. Using these prototype wires, a T-shaped fillet specimen (SM490B, 16 mm thick × 100 mm wide ×
Length 500mm, board thickness 20mm x width 100mm x length 500mm, inorganic zinc primer coating, film thickness 20μ
m, vertical plate end face gas cut), an automatic horizontal fillet welding test was performed by one-pass welding (target leg length 10 mm) and two-pass welding (target leg length 13 mm).

[0028]

[Table 2]

[0029]

[Table 3]

The processing conditions for one-pass welding with a target leg length of 10 mm are as follows. (1) Steel plate: SM490B, thickness 16 mm (2) Specimen: T-shaped fillet (alternate welding on both sides) (3) Welding conditions: current 360A, voltage 26V, speed 25
cm / min Distance between chip base materials 25 mm Shielding gas CO ₂ 25 L / min (4) Wire aiming position Condition A: Torch angle θ _T 45 ° Wire advancing angle θ _W Sweep angle 30 ° Condition B: Torch angle θ _T 60 ° Wire advance angle θ _W Advance angle 20 ° (5) Welding device Automatic welding machine mounted on torch trolley (no oscillate) Table 4 shows the results of the welding test. Table 5 shows the test items and evaluation symbols in Table 4.

[0031]

[Table 4]

[0032]

[Table 5]

As is clear from Table 4, the test Nos. 1~ 10 (W1~W 10) is long leg 10m in one pass
m, stable weldability, good bead shape, good appearance, no change in torch angle and wire advancing angle, no slag entrainment, and no problem with corner penetration Absent. In contrast, test N
o. 11 to 26 are comparative examples. No. 11 (W11)
Is for all orientations of rutile. No. 12 (W12) is a case in which a conventional flux-cored wire for fillet is used.
The appearance is poor, and the cutting of the uprights and the toe are wrapped, making it impossible to form a long leg bead. No. 13 (W13) is unstable less arc alkali metal and bead shape inferior slag encapsulated for TiO ₂ less, appearance becomes defective. No. Conversely, No. 14 (W14 ) had too much TiO ₂ , causing slag entrainment and insufficient penetration.

No. In No. 15 (W15 ), the amount of SiO ₂ was small and slag was involved and insufficient penetration of corners occurred.
No. On the other hand, in the case of No. 16 (W16 ), since the amount of SiO ₂ was too large, cuts occurred in the standing plate, and the toe became a wrapped bead. No. In No. 17 (W17 ), slag was solidified unevenly due to too much MgO, and slag peeling, bead shape, and appearance were poor. No. No. 18 (W18 ) had a small amount of ZrO _{2 and} inferior slag encapsulation, and the bead shape and appearance deteriorated. N
o. On the other hand, in the case of 19 (W19 ), slag peeling was deteriorated due to too much ZrO _2, and the bead shape became uneven. No.
No. 20 (W20 ) contained no Al ₂ O ₃ , degraded slag removability. Also, because of a small amount of alkali metal, the arc was not stable and spatter occurred frequently. No. 21 (W2
In 1 ), the bead became convex because of too much Al ₂ O ₃ . In addition, a cut occurred, and the toe became a wrapped bead.

No. In No. 22 (W22 ), the proportion of SiO _{2 in} the slag forming agent was small, and slag was involved and insufficient penetration of corners occurred. No. On the contrary, in the case of No. 23 (W23 ), the ratio of the SiO ₂ was too large, so that the cut of the standing plate and the lap of the bead toe became noticeable. No.
No. 24 (W24 ) had little iron oxide and the bead toe was poorly aligned. No. In No. 25 (W25 ), since the amount of iron oxide was too large, the bead shape and appearance were poor, and the slag removability was slightly deteriorated. No. No. 26 (W26 ) had excessive spattering, bead shape, poor appearance, slag inclusion and insufficient penetration due to too much F and alkali metal.

[0036]

[Table 6]

[0037]

[Table 6]

[0038]

[Table 7]

Table 6 shows that the test Nos. 2
Nos. 7 to 36 (W1 to W10 ) have good welding workability and bead forming properties in slag entrainment and corner formation even in two-pass welding with a leg length of 13 mm in which the target position of the wire tip in the first pass is further away from the corner. Insufficient penetration of the part does not occur. In addition, the effect of Ni addition on penetration was clearly recognized. On the other hand, Test No.
37 to 42 (W15, W16, W18, W22, W2
3, W27 ) cannot be applied to a place where such a large leg length is required, because bead forming property and welding defect resistance are not compatible with each other. In addition, No. In No. 42 (W27 ), since the content of the deoxidizing agent was too large, bead cracks occurred in the crater portion and the vicinity of the crater in the first pass.

[0040]

As described above, the present invention provides a flux-cored wire for gas shielded arc welding which is used for horizontal fillet welding of thick plates and has a large leg length bead forming property and in which welding defects are hardly generated in a welded portion. It can greatly contribute to higher efficiency and lower cost of welding.

[Brief description of the drawings]

FIG. 1 is a view showing a target position of a wire in horizontal fillet welding of a long leg,

FIG. 2 is a diagram showing a torch angle and a wire advancing angle;

FIG. 3 is a diagram showing an example of a horizontal fillet welding member and its welding procedure.

FIG. 4 is a view showing the effect of the flux-cored wire according to the present invention;

FIG. 5 is a view showing a cross-sectional structure of a flux-cored wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire 2 Standing plate 3 Lower plate 4 Corner part 5 Bead 6 Winding welded part 7 Steady part 8 Side plate 9 Outer part 10 Flux

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takeo Adachi 3-5-4 Tsukiji, Chuo-ku, Tokyo Nippon Steel Welding Industry Co., Ltd. (56) References JP 4-300091 (JP, A) JP JP-A-2-99297 (JP, A) JP-A-4-224094 (JP, A) JP-A-5-269592 (JP, A) JP-A-59-104291 (JP, A) JP-A-61-137695 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 35/368

Claims (2)

(57) [Claims] 1. A flux-cored wire for gas shielded arc welding comprising a steel sheath filled with a flux, comprising the following components as essential components with respect to the total weight of the wire, with the balance being iron components of the steel sheath and A flux-cored wire for gas shielded arc welding, comprising iron powder. TiO _2: 4.5 to 7.5 wt% SiO _2: 2.1 to 3.0 wt% MgO: 0.5 to 3.0 wt% ZrO _2: 0.5 to 2.0 wt% Al ₂ O ₃ : 0.1 to 1.0% by weight, provided that SiO ₂ / (TiO ₂ + SiO ₂ + MgO + Zr
O ₂ + Al ₂ O ₃ ): 0.16 to 0.25 Iron oxide: 0.3 to 1.5% by weight F: 0.03 to 0.35% by weight One or more of Na, K, and Li Total: 0.05
-0.35% by weight Deoxidizing agent (including the outer skin component): 1.5-5.0% by weight 2. The method according to claim 1, further comprising adding 0.1% of Ni.
A flux-cored wire for gas shielded arc welding, characterized in that the flux-cored wire contains about 1.0% by weight.