JP2003071590A - Horizontal fillet gas shield arc welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide horizontal fillet gas shield arc welding method wherein an arc is stabilized, the generation amount of a spatter is small, and deep penetration can be obtained, even under the welding condition of a large current and a high speed. SOLUTION: In the horizontal fillet gas shield arc welding method, a wire filled with a flux, which contains, in terms of total mass% of the wire in the steel outer skin of which the flux is filled, 0.3-1.8% Si, 0.8-4.0% Mn, and a 0.05-1.8% arc stabilizer, and whose flux filled rate is 3-10%, is used to conduct the welding of the horizontal fillet part composed of a bottom plate and a vertical plate. And the arc stabilizer contains one kind or two kinds or more of 1.8% or less synthetic material containing Na2 O and TiO3 , 0.6% or less Na2 O source converted into Na2 O separately from the synthetic material containing Na2 O and TiO2 , and 1.8% or less TiO2 source converted into TiO2 . Further, the welding current is 250-500 A in the case where the wire diameter is 1.2 mm, 300-55 A in the case of 1.4 mm, and 350-600 A in the case of 1.6 mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal fillet gas shield arc welding method using a flux-cored wire for welding various steel structures in bridges and ships.
The present invention relates to a horizontal fillet gas shielded arc welding method in which the arc condition is extremely good, there is little spatter, and deep penetration performance is obtained.

[0002]

2. Description of the Related Art In recent years, in the field of bridges and shipbuilding, a wire diameter of 0.
The application of 8-2.0 mm flux-cored wires is increasing. Above all, in horizontal fillet gas shielded arc welding, which has a high proportion of the total welding length, high speed welding is strongly desired. Further, in horizontal fillet gas shielded arc welding in the field of bridges, it is required that stable deep penetration be obtained in addition to the speeding up of the welding.

As a flux-cored wire capable of high-speed horizontal fillet gas shielded arc welding, for example, in Japanese Patent Laid-Open No. 9-94692, by limiting the wire components including the filling flux, the welding speed is 1 m / min.
There is a disclosure of a technique for improving the bead shape, the bead familiarity and the slag releasability under the conditions of. In addition, JP-A-6
In Japanese Patent No. 234075, by limiting the component composition of the flux-cored wire and adopting the one-pool welding method with two electrodes, it is possible to obtain a welded portion with stable arc, less spatter, and good bead shape. There is a description.

However, when horizontal fillet welding is performed under the welding conditions of high speed and high current using the flux-cored wire described in Japanese Patent Laid-Open No. 9-94692, the arc is unstable and the amount of spatter is generated. As the number increases, a deep penetration cannot be obtained. In addition, JP-A-6-23407
In the method of two-electrode welding described in Japanese Patent Publication No. 5, the welding speed is increased, but since it uses two electrodes, the equipment around the welding torch becomes large in terms of welding work, and the equipment investment becomes expensive. There is a problem that deeper penetration cannot be obtained.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a horizontal fillet gas shielded arc welding method in which the arc is stable even under high current and high speed welding conditions, the amount of spatter is small, and deeper penetration is obtained. It is an object of the present invention to provide a horizontal fillet gas shielded arc welding method.

[0006]

DISCLOSURE OF THE INVENTION The gist of the present invention is a horizontal fillet gas shielded arc welding method in which the total mass% of the wire of a wire in which a steel shell is filled with flux is S
Flux-cored wire containing i: 0.3 to 1.8%, Mn: 0.8 to 4.0%, arc stabilizer: 0.05 to 1.8%, and a flux filling rate of 3 to 10%. Is used to weld a horizontal fillet portion composed of a lower plate and a standing plate.

The arc stabilizer is Na ₂ O and Ti.
O ₂ The following composition is 1.8% containing, apart from the composition containing Na ₂ O and TiO _2, Na ₂ O source in terms of Na ₂ O values 0.
It is 6% or less, and the TiO ₂ source is 1.8% or less in terms of TiO ₂ and is 1 type or 2 or more types. Further, when the welding current is 1.2 mm, the wire diameter is 250 to 500 A, 1.4 mm is 300 to 550 A, and 1.6 mm is 350 to 60 A.
It is a horizontal fillet gas shielded arc welding method which is also characterized by 0A.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have studied in detail the composition and the like of a flux-cored wire used in a horizontal fillet gas shielded arc welding method performed under welding conditions of high current and high speed. As a result, a compound containing Na ₂ O and TiO ₂ in a deoxidizing agent composed of Si and Mn in an appropriate range for the flux filled in the flux-cored wire, Na ₂ O,
Inclusion of TiO ₂ alone or in combination with an arc stabilizer promotes the detachment of droplets during welding, increases the droplet size and the number of transitions, and stabilizes the arc and reduces spatter. It was found that the problem of flux penetration wire having a shallow penetration depth can be solved by further reducing the flux filling rate.

The reasons for limiting the component composition of the flux-cored wire used in the horizontal fillet gas shielded arc welding method of the present invention will be described below. Si is the wire mass% (hereinafter,%
Say. ) And 0.3 to 1.8%. Si is used as a deoxidizer and has an effect of reducing the amount of oxygen in the weld metal. However, if it is less than 0.3%, the viscosity of the weld metal becomes low and the beads drop to the lower plate side. Furthermore, the deoxidizing power is insufficient and blowholes are generated in the weld metal. Also,
If it exceeds 1.8%, the yield of the Si component in the weld metal becomes excessive, the strength of the weld metal increases, and cracks easily occur.

Mn is set to 0.8 to 4.0%. Mn promotes deoxidation of the weld metal, enhances the fluidity of the molten metal, and improves the weld bead shape. If Mn is less than 0.8%, the bead shape becomes convex and blow holes are generated. Also, if it exceeds 4.0%, the droplets become large,
The effect of reducing spatter is lost, the yield of deposited metal becomes excessive, the strength of the weld metal increases, and cracks easily occur. The contents of Si and Mn are Si and Mn of the steel shell, metallic Si, metallic Mn or Fe-Si, Fe-S.
It is the conversion value of Si and Mn of iron alloys such as i-Mn and Fe-Mn.

Next, the amount of the arc stabilizer added and its effect will be described. Add an arc stabilizer to the filling flux.
By adding 05 to 1.8%, the arc state is good, the droplets are small and stable, and the amount of spatter generated is extremely small. If the arc stabilizer content is less than 0.05%, the arc breakage that occurs at the moment when the droplets migrate cannot be prevented. Further, the fluctuation of the arc length is large, the number of times droplets are transferred is small, the droplets are large, the arc is unstable, and the amount of spatter is increased. If the amount of the arc stabilizer exceeds 1.8%, the arc becomes unnecessarily long, the spatter generation amount increases, and undercut occurs. Incidentally, the arc stabilizer is Na ₂ O and composites containing TiO _2, Na ₂ O source terms of Na ₂ O values and TiO ₂ source using one or more of TiO ₂ equivalent.

Na, which is the arc stabilizer of the filling flux
_The content of the compound containing ₂ O and TiO ₂ is 1.8% or less.
The compound containing Na ₂ O and TiO ₂ prevents arc breakage that occurs at the moment the droplets migrate, improves the arc state, and reduces the amount of spatter generation. Na ₂ O and T
If the compound containing iO ₂ exceeds 1.8%, the arc break can be prevented, but the arc length becomes longer than necessary, the spatter generation amount increases, the fume generation amount also increases, and the undercut also occurs. Occur.

Na₂O and TiO₂The compound containing
iO₂Ternary compound containing Na, Na₂O and TiO₂of
Similar effects can be obtained even with various ratios of synthetic products.
And is included in the technical idea of the present invention. Na₂O and TiO₂
The compound containing is sodium titanate, for example,
High temperature treatment by mixing sodium and rutile in the desired ratio
Can be obtained by₂O is 10
TiO at 50%₂Of the ratio within the range of 50 to 90%
It is desirable to use a synthetic product. For example, 13Na ₂O-
80 TiO₂, 20Na₂O-73TiO₂, 42Na₂O
-53TiO₂, Or 13Na₂O-25SiO₂−
58 TiO₂Examples include synthetic products containing
However, it is not limited thereto.

The Na ₂ O source of the arc stabilizer is 0.6% or less in terms of Na ₂ O conversion value. Na ₂ O sources are Na ₂ O and Ti
An additive component other than a compound containing O ₂ or SiO ₂ ,
It has the effect of reducing the fluctuation of the arc length during welding and increasing the number of droplet transfers, that is, promoting the atomization of droplets. However, if it exceeds 0.6%, the number of droplet transfer decreases,
Only the arc length tends to be long, resulting in an increase in the amount of spatter and undercut. Sources of Na ₂ O include sodium carbonate and soda glass.

The TiO ₂ source of the arc stabilizer is 1.8% or less in terms of TiO ₂ . TiO ₂ sources are Na ₂ O and Ti
An additive component other than a compound containing O ₂ or SiO ₂ ,
As an arc stabilizer, it has an effect of promoting a downward electromagnetic pinch effect that stabilizes the droplet transfer by enlarging the generation area of the arc generated at the droplet tip. However, if it exceeds 1.8%, the downward electromagnetic pinch force becomes excessive and the droplet transfer becomes unstable. Sources of TiO ₂ include titanium oxide, rutile, titanium slag, illuminite and the like.

The flux filling rate of the flux-cored wire used in the present invention is 3 to 10%. If the flux filling rate is less than 3%, it becomes difficult to fill and mold the flux, resulting in poor productivity. Further, if the flux filling rate exceeds 10%, the amount of slag and the amount of spatter are increased, and the penetration of the weld metal becomes shallower, so that the performance of the wire cannot be improved. However, considering higher productivity, low slag generation, low spatter, and deep penetration,
The flux filling rate is preferably 4 to 8%.

The welding current is 2 when the wire diameter is 1.2 mm.
50 to 500 A, 300 to 550 A for 1.4 mm,
In the case of 1.6 mm, it is 350 to 600 A. When the welding current is less than 250 A when the wire diameter is 1.2 mm, less than 300 A when the wire diameter is 1.4 mm, and less than 350 A when the wire diameter is 1.6 mm, the arc is unstable and the amount of spatter is increased. In addition, the penetration depth becomes shallow. Welding current is 1.2 wire diameter
When it is more than 500 A in the case of mm, more than 550 A in the case of 1.4 mm and more than 600 A in the case of 1.6 mm, the arc is excessively blown, the amount of spatter is increased, and undercut easily occurs, and the bead shape is deteriorated.

The above is the constitution of the present invention. As a component which can be added to the filling flux, a deoxidizing agent such as Al, Mg and Zr is used to remove the weld metal in the same manner as in the usual flux-cored wire for gas shielded arc welding. Included to generate blowholes due to lack of acid and / or to adjust mechanical properties. However, if these elements are excessively contained, the slag removability due to slag seizure is poor, the bead appearance is poor, or the strength of the weld metal is excessive and crack resistance deteriorates. In addition,
The deoxidizer is slag in addition to acting as a yield alloying agent in the weld metal, and also affects the composition and amount of molten slag, which may impair the intended effect of the present invention.
It is desirable to limit the content appropriately.

In the present invention, Bi, S and the like can be appropriately added as components for improving the peelability of the slag covering the weld bead within a range not affecting the basic technical idea of the present invention. In addition, depending on the type of steel, N and N
It is also possible to add i, Cr, Mo, Ti, B or the like. The wire diameter of the flux-cored wire used in the present invention is used for horizontal fillet welding under the conditions of high current and high speed welding, so taking into consideration the stability of the wire feeding speed and the target position deviation of the wire tip. 2 to 1.6 mm. As the arc welding shield gas used in the present invention, sufficient welding workability can be obtained by using CO ₂ gas, but in consideration of the environment at the time of welding workability, the amount of fumes generated is reduced.
It may be used r-CO ₂ mixed gas.

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLES Table 1 shows flux-cored wires prepared for use in the present invention and comparative examples. The wire sheath has C: 0.04%, Si: 0.01%, Mn: 0.
30%, P: 0.020%, S: 0.015% band steel is used, filled with flux in the forming step, formed into an O-shape, and expanded to a wire diameter of 1.2 to 1.6 mm after welding. I made a line and made a prototype. Using these trial wires, a T-shaped fillet test piece (steel type: SM49 consisting of the standing plate and the lower plate shown in FIG. 1 was used.
0B, standing plate: plate thickness 9 and 12 mm, width 100 mm, length 1000 mm, lower plate: thickness 20 mm, width 150 mm,
Welding conditions (welding voltage: 1000 mm) shown in Table 2
As shown in FIG. 2, both sides were horizontally fillet welded at 25 to 40 V, the distance between the tip and the base metal: 25 mm, and the shielding gas: CO ₂ 25 liter / min.

[0021]

[Table 1]

The amount of spatter generated and the state of the arc were observed during welding, the appearance of the bead was observed after welding, the penetration depth was measured, and the presence or absence of blowholes was examined. It should be noted that the amount of spatter generated was good when the amount collected was 1.50 g / min or less. As for the penetration depth, five cross-section macros were taken from the test piece after welding, and the penetration depths t1 and t2 of each cross-section macro were measured as shown in FIG. 2, and the shallowest penetration depth was determined to be 3 mm or more. . The presence or absence of brohole was examined by observing the fracture surface of the remaining test piece obtained by collecting the macro section, by slitting the bead surface and breaking the bead in the longitudinal direction. The results are summarized in Table 2.

[0023]

[Table 2]

In Table 2, No. 1-No. 9 is an example of the present invention,
No. 10-No. 20 is a comparative example. No. 1, which is an example of the present invention. 1-No. 9 is the used wire symbol W1 to W
The components (arc stabilizer, amount of Si and Mn) and flux filling rate of 9 are appropriate, and the welding current is also appropriate, so that the arc is stable, the amount of spatter is small, the bead appearance is good, and deep penetration occurs. Was obtained, and there was no occurrence of brohol, which was a very satisfactory result.

In the comparative example, No. No. 10 is Na ₂ O and TiO ₂ which are arc stabilizers of the wire symbol W10 used
Since the amount of organic compounds containing is low, the arc is unstable and the amount of spatter is increased. Further, since the Si content is low, the viscosity of the weld metal becomes low and the beads droop toward the lower plate. No. 11
Is N, which is the arc stabilizer of the wire symbol W11 used.
a ₂ O and TiO ₂ of polymerizable material and TiO ₂ source containing TiO ₂
Since the total amount with the converted value is high, the amount of spatter generated is large,
Undercut also occurred. Further, since Si is high, hot cracking occurred in the crater portion.

No. 12 is the used wire symbol W12
The amount of fumes and spatters was large, and undercuts were generated because the amount of the compound containing the arc stabilizers Na ₂ O and TiO ₂ was high. Also, Mn
Is low, the bead appearance was a convex bead. No. 1
No. 3 had a high Na ₂ O conversion value of the Na ₂ O source which is the arc stabilizer of the wire symbol W13 used, so that the amount of spatter generated was large and undercut also occurred. Further, since Mn was high, high temperature cracking occurred in the crater portion.

No. 14 is the used wire symbol W14
Since the TiO ₂ source of the TiO ₂ source, which is the arc stabilizer, has a high TiO ₂ conversion value, a large amount of spatter is generated and undercut also occurs. No. Since No. 15 had a low flux filling rate of the used wire symbol W15, the productivity during wire production was poor, the flux filling rate was variable, the arc was unstable, the amount of spatter generated was large, and undercut also occurred. N
o. In No. 16, since the used wire symbol W16 had a high flux filling rate, the slag generation amount was large, the spatter generation amount was large, and the penetration depth was shallow. No. 1
7 and No. In No. 19, since the welding current was low, the arc was unstable and the amount of spatter generated was large. Also, the penetration depth became shallower. No. 18 and No. In No. 20, since the welding current was high, the arc was blown excessively, the amount of spatter generated was large, and undercut also occurred.

[0028]

As described in detail above, according to the horizontal fillet gas shielded arc welding method of the present invention, the arc state is extremely good even under the welding conditions of high current and high speed.
Small amount of spatter, deep penetration can be obtained, and welding efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a fillet welded test body used in an example of the present invention.

FIG. 2 is a diagram showing a method for measuring a penetration depth in an example of the present invention.

[Explanation of symbols] 1 standing plate 2 Lower plate 3 Weld metal t1, t2 penetration depth

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4E001 AA03 BB09 DA05 EA01 EA04                       EA05 EA07 EA08                 4E081 AA06 AA13 BA40 BB05 CA09                       CA10 DA12 FA14 FA15 YA01                       YX03 YX09 YX12 YX13                 4E084 AA02 BA22 CA24 CA25

Claims (3)

[Claims] 1. In the horizontal fillet gas shield arc welding method, the total mass% of the wire of the steel shell is flux-filled, Si: 0.3 to 1.8%, Mn: 0.
8 to 4.0%, arc stabilizer: 0.05 to 1.8%, and using a flux-cored wire having a flux filling rate of 3 to 10%, a horizontal fillet portion composed of a lower plate and a vertical plate. A horizontal fillet gas shield arc welding method characterized by performing welding. Wherein the arc stabilizer, Na ₂ O and compounds containing TiO ₂ is 1.8% or less, apart from the composition containing Na ₂ O and TiO _2, the Na ₂ O source terms of Na ₂ O The horizontal fillet gas shielded arc welding method according to claim 1, wherein the value is 0.6% or less, and the TiO ₂ source is 1.8% or less in terms of TiO ₂ and one or more kinds. 3. The horizontal fillet gas shield arc welding method according to claim 1, wherein the welding current is in the following range. Wire diameter, 1.2 mm 250-500 A 1.4 mm 300-550 A 1.6 mm 350-600 A