JP2000071096A - Flux cored wire for horizontal fillet gas shield arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flux cored wire for horizontal fillet gas shield arc welding with good welding workability and excellent continuous weldability when high speed horizontal fillet welding is carried out to a coated steel plate coated with shop primer and the like while using a two electrode one pool method. SOLUTION: This flux cored wire filled with flux in a steel-made outer skin contains, against the wire total weight, 0.01-0.04 wt.% C, 0.5-1.0 wt.% Si, 1.5-3.0 wt.% Mn, 0.2 wt.% or less Mg, 0.4 wt.% or less Al, 1.0-4.0 wt.% TiO2, 0.1-0.5 wt.% ZrO2, and 0.1-0.5 wt.% MgO, where the total of Mg and Al is 0.1 wt.% or more. Additionally, the weight ratio of Mg and Al, and Mn: (10Mg+3Al)/Mn is 0.2-1.0, and the weight ratio of ZrO2 and MgO, and TiO2: (ZrO2+MgO)/TiO2 is 0.08-0.20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is suitable for using a coated steel plate such as a shop primer for welding by a high-speed horizontal fillet welding method in which one molten pool is formed by two electrodes. The present invention relates to a flux-cored wire for horizontal fillet gas shielded arc welding, which has good weldability and excellent continuous weldability.

[0002]

2. Description of the Related Art In the field of shipbuilding or bridges, the use of flux-cored wires for gas shielded arc welding has been increasing in order to achieve highly efficient welding of welded structures. Recently, construction methods have been increasing in order to achieve even higher efficiency. Among them,
In horizontal fillet welding, which accounts for a large percentage of the total welding length, the two-electrode, one-pool method, in which two electrodes are used to form one molten pool between electrodes, has already been put into practical use, and high-speed welding has been achieved. ing.

[0003]

However, the two-electrode one-pool method has a high welding speed and is sensitive to the root gap and the like. In general, this method is applied to welding spots with a long welding length of about 20 m. Due to the large amount of spatter, spatter adheres to the nozzle of the welding torch and defects such as pits occur due to poor gas shielding. In some cases, spatter adhered to the nozzle may fall on the welding line, and the number of repair weldings may increase. Further, there is a problem that spatters attached to the nozzle increase in a ring shape, and welding stops due to contact with a welding member.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is intended to perform a high-speed horizontal fillet welding of a coated steel plate coated with a shop primer or the like using a two-electrode one-pool method. It is an object of the present invention to provide a flux-cored wire for horizontal fillet gas shielded arc welding having good weldability and excellent continuous weldability.

[0005]

According to the present invention, there is provided a flux-cored wire for horizontal fillet gas shielded arc welding according to the present invention, wherein the flux is formed by filling a steel sheath with a flux. On the other hand, C is 0.01 to 0.04% by weight, Si is 0.5 to 1.0% by weight, Mn is 1.5 to 3.0% by weight, Mg
0.2% by weight or less, Al 0.4% by weight or less, TiO
₂ is 1.0 to 4.0% by weight, and ZrO ₂ is 0.1 to 0.4% by weight.
5% by weight, 0.1 to 0.5% by weight of MgO, the total amount of Mg and Al is 0.1% by weight or more, and the weight ratio of Mg and Al to Mn (10Mg +
3Al) / Mn is 0.2 to 1.0, and the ZrO
₂ and the weight ratio of MgO to TiO ₂ (ZrO ₂ + MgO)
/ TiO ₂ is 0.08 to 0.20.

The wire of the present invention is suitable for use in a two-electrode, one-pool construction method.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have discussed the problem of high-speed horizontal fillet welding performed by the above-described two-electrode one-pool method with respect to the stability of a pool in a molten pool formed by the two-electrode one-pool method. The research on the improvement of the flux cored wire mainly used for improving the quality of the wire was repeated. As a result, it has been found that the wire having the composition described in the claims of the present application can solve the above problem in high-speed horizontal fillet gas shielded arc welding.

The reason for limiting the composition of the flux component contained in the flux cored wire for high-speed horizontal fillet gas shielded arc welding according to the present invention will be described below.

[0009]C: 0.01 to 0.04% by weight  C obtains toughness by improving strength or hardenability
Factors that strongly affect the arc blowing force
Is prime. When the content of C is less than 0.01% by weight
Means that a stable penetration depth cannot be obtained
And spreads vertically and is not stable. Also, the content of C is
If it exceeds 0.04% by weight, acid in the welding arc
The reaction with the element becomes too active, and spatter increases. Subordinate
Therefore, the content of C is set to 0.01 to 0.04% by weight.
You.

[0010]Si: 0.5 to 1.0% by weight  Si is deoxidizer, strength and beat shape in high speed horizontal welding
There is an effect of improvement. Si content of less than 0.5% by weight
In this case, pores may be generated due to insufficient deoxidation and
It becomes a convex shape due to a poor defect. When the content of Si is 1.0
If the amount exceeds the weight percent, the arc becomes too strong and the spa
And the amount of Si in the deposited metal becomes excessive,
Deterioration of toughness occurs. Therefore, the content of Si is 0.5
It is set to 1.0% by weight.

[0011]Mn: 1.5 to 3.0% by weight  Mn is similar to Si with deoxidizer, strength and high-speed horizontal welding.
This has the effect of improving the beat shape. Mn content is 1.5
If the amount is less than 10% by weight, generation of pores due to insufficient
The bead shape becomes convex. Further, the content of Mn is 3.0.
If it exceeds 10% by weight, the arc will be too strong
As the data increases, the strength of the deposited metal becomes excessive. Follow
The content of Mn is 1.5 to 3.0% by weight.

[0012]Mg: 0.2% by weight or less  Mg acts as a deoxidizer and reduces the amount of oxygen in the deposited metal.
As well as toughness, arc spread and molten metal
It has the effect of adjusting the liquidity of the genus. Mg content of 0.2
If the amount exceeds 100% by weight, the fluidity of the
The increase in the blowing force synergistically increases the spatter. Subordinate
Therefore, the content of Mg is set to 0.2% by weight or less.

[0013]Al: 0.4% by weight or less  Al acts as a deoxidizing agent in the same manner as Mg,
While reducing the amount of oxygen, ensuring toughness and widening the arc
And has the effect of adjusting the fluidity of the molten metal. Including Al
If the weight exceeds 0.4% by weight, the turbulence
And spatter increases. Therefore, the content of Al
Is 0.4% by weight or less.

[0014]Total amount of Mg and Al: 0.1% by weight or more  When the total amount of Mg and Al is 0.1% by weight or less, Mg or Al
Cannot obtain the effect of Al. Effect of Mg or Al
At least 0.1% by weight is necessary to obtain
You. Therefore, the total amount of Mg and Al is 0.1% by weight or more.
And

[0015](10Mg + 3Al) / Mn: 0.2 to
1.0  When (10Mg + 3Al) / Mn is less than 0.2,
The bead shape tends to be convex and the porosity resistance
to degrade. Also, (10Mg + 3Al) / Mn is 1.0
If it exceeds, the porosity will deteriorate and the welding
Undercuts are likely to occur in the cable. Therefore, (1
0Mg + 3Al) / Mn is set to 0.2 to 1.0.

[0016]TiO ₂ : 1.0 to 4.0% by weight  TiO_TwoImproves the stability of the arc and
Has the effect of uniformly enclosing the bead surface and improving the bead appearance.
is there. TiO_TwoIs less than 1.0% by weight
Can not maintain the stability of the arc, spatter increases,
The bead appearance also deteriorates. Also, TiO_TwoIs 4.0% by weight
If it exceeds the limit, the stability of the arc is maintained, but the
The bead shape is overlaid due to the large amount of
And the occurrence of pore defects increases. Subordinate
What is TiO_TwoIs 1.0 to 4.0% by weight.
You.

[0017]ZrO ₂ : 0.1 to 0.5% by weight  ZrO_TwoAdjusts the solidification temperature and viscosity of the molten slab,
This has the effect of improving the bead shape. ZrO_TwoContent of
Is less than 0.1% by weight, the solidification temperature of the molten slab
And the effect of adjusting the viscosity and improving the bead shape
I can't. In addition, ZrO_TwoContent exceeds 0.5% by weight
The arc becomes too strong and spatter increases.
Add. Therefore, ZrO_TwoContent of 0.1 to 0.5
% By weight.

[0018]MgO: 0.1 to 0.5% by weight  MgO is ZrO_TwoSimilarly to the solidification temperature of the molten slab,
It has the effect of adjusting the viscosity and viscosity and improving the bead shape.
If the MgO content is less than 0.1% by weight,
Adjust the solidification temperature and viscosity of the rub to improve the bead shape
No effect is observed. Further, when the content of MgO is 0.1.
If it exceeds 5% by weight, the arc becomes too strong,
Spatter increases. Therefore, the content of MgO is 0.1
To 0.5% by weight.

(ZrO ₂ + MgO) / TiO ₂ : 0.08
To 0.20  ZrO_Two, MgO and TiO_TwoContent depends on the respective amount.
It is necessary to increase or decrease appropriately. That is, Equation 1
Within a satisfactory range, ZrO_Two, MgO and TiO_Twoof
The content is limited.

[0020]

## EQU1 ## 0.08 ≦ (ZrO ₂ + MgO) / TiO ₂ ≦
0.20 FIG. 1 is a graph showing characteristics of welding workability depending on the amount of the added element. In FIG. 1, a region S is composed of ZrO ₂ , M
The range of the content of gO and TiO ₂ is shown. Region A is a region where welding workability is good. The area B is an area in which a failure in bead adaptation occurs. The region C is a region in which the increase in spatter and the stability of the basin are deteriorated. Region D indicates a range in which the porosity and bead shape overlap when the amount of TiO ₂ added increases.

That is, when (ZrO ₂ + MgO) / TiO ₂ is less than 0.08, it corresponds to the range shown in the region B in FIG. 1, and the bead shape is changed due to the solidification temperature of the molten slag and the decrease in viscosity. to degrade. Also, (ZrO ₂ + M
When gO) / TiO ₂ exceeds 0.20, it corresponds to the range shown in the region C in FIG. 1, and the arc force becomes too strong, so that the spatter increases and the stability of the hot water pool deteriorates. Therefore, (ZrO ₂ + MgO) / TiO ₂ is 0.1%.
08 to 0.20.

As described above, the conditions such as the material of the steel sheath, the flux rate, the wire cross-sectional shape, the wire diameter, and the type and amount of the shielding gas in the flux cored wire for high-speed horizontal fillet gas shielded arc welding of the present invention are appropriately selected. There is no restriction.

In the present invention, by appropriately defining the type and content of the oxide contained in the flux in the flux-cored wire and the ratio thereof, good welding workability can be obtained and excellent. Continuous weldability can be obtained.

[0024]

EXAMPLES Examples of the flux-cored wire for shielding gas arc welding according to the present invention will be described in detail below in comparison with comparative examples.

A flux having a chemical composition shown in the following Tables 1 and 2 was filled into a mild steel sheath at a flux rate of 15% to produce a flux-cored wire having a wire diameter of 1.6 mm. In Table 1, x indicates that the additive element was not actively added.

Using these wires, welding experiments were performed under the welding conditions shown in FIGS. FIG. 2 is a cross-sectional view showing a welded joint. FIG. 3A is a top view showing a welding method used in a welding experiment, and FIG. 3B is a front view of FIG.

In this embodiment, the substrate 1 and the upper plate 2 are formed as T-shaped fillet joints, and the leading electrode 4 and the trailing electrode 4 are respectively provided at the corners on both sides of the steel plate coated with the inorganic zinc primer 3. The pole 5 is placed with the distance d between the electrodes. The leading pole 4 and the trailing pole 5 are each fixed to the substrate 1 at a torch angle α, and the leading pole 4 is a receding angle β and the trailing pole 5 is a advancing angle δ with respect to the longitudinal direction of the substrate 1. Is fixed with. Further, the leading electrode 4 is set at a corner at the target position, and the trailing electrode 5 is set at a distance s from the corner at the target position. In this state, welding is performed in the welding direction F.

The welding test results are shown in Tables 4 and 5 below.
In the evaluation result columns shown in Tables 4 and 5 below,
も の indicates that excellent results were obtained, △ indicates slightly poor results, and × indicates extremely poor results.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

[0033]

[Table 5]

As shown in Tables 4 and 5, the composition and the content ratio of the wire are within the range of T1 to T6 within the range of the present invention.
Has good arc weldability, so the amount of spatter adhered to the nozzle of the welding torch is extremely small, and the weldability is excellent. Also, the bead shape is good and the porosity resistance is excellent.

On the other hand, in T7 to T24, as shown in Tables 4 and 5, the composition and content ratio of the wire are out of the range of the present invention. T7 has a C content of 0.003% by weight.
Therefore, the hot pool is not stable, the spatter deposition amount on the nozzle increases, and the bead shape is deteriorated. T8 is
Since the C amount is as large as 0.06% by weight, the arc becomes too strong, and the spatter adhesion amount of the nozzle increases.

In T9, the amount of Si is as small as 0.3% by weight, the porosity is deteriorated due to insufficient deoxidation, and the bead becomes convex. T10 is when the amount of Si is 1.3% by weight.
In many cases, the arc is too strong and the stability of the hot water pool is lacking, so that the spatter deposition amount of the nozzle increases.

In T11, the amount of Mg is as small as 1.3% by weight, and the porosity resistance is deteriorated due to insufficient deoxidation, and the bead break-in failure occurs. In T12, the amount of Mn is as large as 3.5% by weight, the arc is too strong, and the stability of the pool is lacking, so that the spatter deposition amount of the nozzle increases.

In T13, the amount of Mg is as large as 0.3% by weight, the fluidity of the basin is too low, the arc is too strong, the amount of spatters generated is remarkably increased, and the amount of spatter adhered to the nozzle is increased. .

In the case of T14, the amount of Al is as large as 0.6% by weight, and the stability of the pool is deteriorated, so that the amount of spatter adhered to the nozzle increases.

In T15, (10Mg + 3Al) / Mn is as small as 0.1, and the deterioration of porosity is remarkable.
In T16, (10Mg + 3Al) / Mn was as large as 1.1, and the porosity resistance was significantly deteriorated.

In T17, since the amount of TiO ₂ is as small as 0.8% by weight and the arc stability cannot be maintained, the spatter increases and the spatter deposition amount of the nozzle increases.
In T18, the content of TiO _{2 is} as large as 4.4% by weight, and the arc stability is maintained, but the bead shape tends to overlap and the porosity is significantly deteriorated.

T19 is (ZrO ₂ + MgO) / TiO ₂
Is as small as 0.07, so that the solidification temperature of the molten slag is excessively lowered and the bead shape is deteriorated. T20 is (ZrO
₂ + MgO) / TiO ₂ is as large as 0.22, the arc becomes too strong, the stability of the basin is deteriorated, the spatter increases, and the spatter adhesion amount of the nozzle increases.

In T21, since ZrO ₂ is not positively added, if it is too small, the bead shape, particularly the adaptation of the toe, deteriorates. In T22, the amount of ZrO ₂ was 0.1.
As much as 6% by weight, the arc becomes too strong, and the spatter adhesion amount of the nozzle increases.

In T23, since MgO is not added positively, the bead shape is deteriorated. Also, Mg + Al
Is too small because Mg and Al are not positively added, and the effect of adjusting the fluidity of the molten metal cannot be obtained, so that spatter increases. In T24, the amount of MgO is as large as 0.6% by weight, the spatter increases due to the influence of the arc force, and the spatter adhesion amount of the nozzle increases.

[0045]

As described above in detail, according to the present invention, the arc weldability can be improved by appropriately defining the type and content of the oxide contained in the flux in the flux-cored wire and their ratio. Therefore, the amount of spatter adhered to the nozzle of the welding torch is extremely small, and good welding workability can be obtained. In addition, the bead shape is excellent, the pore resistance is excellent, and stable continuous weldability can be obtained.

Further, since it is possible to eliminate waste such as welding stop or repair welding, it is possible to improve efficiency and reduce total cost.

[Brief description of the drawings]

FIG. 1 is a graph showing characteristics of welding workability depending on the amount of an additive element.

FIG. 2 is a sectional view showing a welded joint according to an embodiment of the present invention.

3A is a top view showing a welding method according to an embodiment of the present invention, and FIG. 3B is a front view of FIG.

[Explanation of symbols]

 1; substrate 2; upper plate 3; inorganic zinc primer 4; leading electrode 5; trailing electrode A, B, C, D, S; region d; electrode spacing s; distance α; torch angle β; receding angle γ; Corner

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Makoto Ota 100-1 Urakawachi, Miyama-ji, Fujisawa-shi, Kanagawa Prefecture F-term in Kobe Steel Fujisawa Works (reference) 4E001 AA03 BB06 CA01 DA05 DB03 DC05 DC06 EA07 4E081 BA02 BA40 BB05 CA07 DA12 4E084 AA02 AA04 AA11 BA03 BA04 BA05 BA10 BA18 CA23 CA24 DA10 DA28 DA29 GA12 HA01

Claims (2)

[Claims] 1. A flux-cored wire comprising a steel sheath filled with a flux, wherein the flux has a C content of 0.01 with respect to the total weight of the wire.
To 0.04% by weight, Si to 0.5 to 1.0% by weight,
Mn 1.5 to 3.0 wt%, Mg 0.2 wt% or less, 0.4 wt% or less Al, the TiO ₂ 1.0 to 4.0 wt%, a ZrO ₂ 0.1 to 0.5% by weight, M
containing 0.1 to 0.5% by weight of gO;
Is not less than 0.1% by weight, and the weight ratio of Mg and Al to Mn (10Mg + 3Al) / Mn
A horizontal fillet gas, wherein the weight ratio of ZrO ₂ and MgO to TiO ₂ (ZrO ₂ + MgO) / TiO ₂ is 0.08 to 0.20. Flux-cored wire for shield arc welding. 2. The flux cored wire for horizontal fillet gas shielded arc welding according to claim 1, which is used for a two-electrode one-pool construction method.