JPH11129093A - Flux cored wire for welding austenitic stainless steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flux cored wire for welding the austenitic stainless steel; wherein pore resistance is excellent, and the spatter generation volume is reduced, and slag exfoliation is improved so as to obtain good welding workability. SOLUTION: The flux of the flux cored wire for welding austenitic stainless steel contains, at weight % per total weight of wire, 0.1-0.5% metallic fluoride (F conversion value), 2.6-8.5% TiO2 , 0.01% or more and less than 0.10% K2 O, 0.01% or more and less than 0.10% Na2 O, 0.05-0.44% Al2 O3 , and 0.7-5.5% SiO2 . Also, the total weight of K2 O and Na2 O content is restricted to be 0.15 wt.% or less, and the ratio ([SiO2 ]/ [F]) of the SiO2 content [SiO2 ] and the metallic fluoride (F conversion value) [F] is 6.5-12. Furthermore, ZrO2 per total weight of wire is restricted to be below 0.1 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to CO ₂ gas or Ar
Flux-cored wire used for gas-shielded arc welding using a mixed gas of gas and CO ₂ gas as a shielding gas, especially welding work that has excellent porosity resistance, low spatter generation, and excellent slag peeling properties The present invention relates to a flux-cored wire for welding austenitic stainless steel having good properties.

[0002]

2. Description of the Related Art A flux-cored wire for austenitic stainless steel welding has excellent welding efficiency and good welding workability. I have. Along with this, flux-cored wires for welding austenitic stainless steel are strongly required to have improved welding workability such as reduction of welding defects such as pits and blowholes, reduction of spatter generation and improvement of slag peelability. ing.

[0003] By the way, at the time of gas shielded arc welding,
If slag entrainment or the like occurs due to a decrease in pits, blowholes, or slag removability, the integrity of the weld metal is impaired, and a process of repairing the weld metal is required.
Further, if spatter is generated when welding stainless steel, the appearance of the weld is deteriorated, and the spatter becomes a starting point of corrosion, so that a step of removing spatter is required. Therefore, if the wire characteristics required for flux-cored wires for austenitic stainless steel welding in recent years can be improved, extra working steps at the time of welding can be reduced. Can be improved in productivity.

[0004] The pits and blowholes are generated due to construction conditions such as an excessive or insufficient shield gas flow rate and a poor shield condition due to a cross wind, and between the pits and blowholes such as adhesion of moisture to a welded portion and moisture absorption of flux in the wires. It may be caused by deterioration of porosity. The porosity resistance of a wire indicates the resistance of the wire itself to the occurrence of pits and blowholes. Therefore, in order to prevent moisture absorption of the flux in the wire, a wire having a seamless structure in which the flux is completely shielded from the atmosphere by an outer cover is applied to some of the flux-cored wires. However, even when the flux-cored wire having the seamless structure is used, pits and blow holes may be generated depending on the surface condition of the workpiece. Also,
A flux-cored wire with such a seamless structure
There is also a problem that production costs increase.

[0005] As wires having improved porosity, in addition to wires having a seamless structure, flux-cored wires for welding stainless steel in which the contents of carbonate and fluoride in the wires are appropriately defined are disclosed. (Patent No. 26026
04). This wire contains one or both of fluorine and carbon dioxide gas generating material, and generates fluorine gas or carbon dioxide gas at the time of welding, so that the hydrogen partial pressure in the arc atmosphere is reduced and the pore resistance is reduced. Performance can be improved.

On the other hand, a stainless steel welding wire which has reduced the amount of spatter has been proposed (Japanese Patent Application Laid-Open No. 58-1983).
No. 70993). This wire contains 10 times or more of SiO ₂ than the content of metal fluoride.

[0007]

However, when welding is performed using the wire disclosed in Japanese Patent No. 2602604, spatters are generated due to generation of carbon dioxide gas and fluorine gas, and welding workability is deteriorated. is there. In addition, when welding is performed using a carbonate-containing wire, the amount of carbon in the weld metal increases, and the corrosion resistance may deteriorate.

Further, as proposed in Japanese Patent Application Laid-Open No. 58-70993, if the content of SiO _{2 in} the wire is at least 10 times that of metal fluoride, the amount of spatter generated can be sufficiently reduced. Is difficult.

As described above, there has not been proposed any conventional flux-cored wire for stainless steel that satisfies both excellent porosity resistance and good welding workability at the same time.
Therefore, development of a flux cored wire for austenitic stainless steel welding which can improve both of these properties is required.

[0010] The present invention has been made in view of the above problems, has excellent porosity resistance, can reduce the amount of spatter generation and can improve the slag peelability,
Accordingly, an object of the present invention is to provide a flux-cored wire for austenitic stainless steel welding capable of obtaining good welding workability.

[0011]

A flux-cored wire for welding austenitic stainless steel according to the present invention is a flux-cored wire obtained by filling a sheath of austenitic stainless steel with a flux, wherein the flux has a total weight of the wire. Metal fluoride (F conversion value): 0.1 to 0.5% by weight, TiO ₂ : 2.6 to 8.5% by weight, K ₂ O: 0.01 to less than 0.10% by weight , Na ₂ O: 0.01 to less than 0.10% by weight, Al ₂ O ₃ : 0.05 to 0.44% by weight and S
iO ₂ : 0.7 to 5.5% by weight, the total content of the K ₂ O and the Na ₂ O is regulated to 0.15% by weight or less, and the SiO ₂ content is [SiO ₂ ] by weight% and the content of the metal fluoride (F conversion value) by weight% [F], ([SiO ₂ ] / [F])
Is 6.5 to 12.0, and ZrO ₂ per total weight of the wire is regulated to less than 0.10% by weight.

In one or both of the outer coat and the flux, the total amount of one or two selected from the group consisting of N and nitrogen compounds is 0.005 to 0. 090% by weight,
It is preferable that the content of the metal carbonate in the flux is regulated to less than 0.05% by weight based on the total weight of the wire in terms of CO ₂ .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In order to solve the above-mentioned problems, the present inventors conducted various studies on components contained in a flux and their contents. As a result, it has been found that it is necessary to include a predetermined amount of metal fluoride in the flux in order to improve the porosity resistance of the wire. On the other hand, the present inventors have found that F in metal fluoride has an effect of improving arc stability.
In addition, the present inventors have found that alkali metal oxides such as Na ₂ O and K ₂ O, which are generally used as arc stabilizers, have a higher arc content in wires containing fluorine than conventional wires. They have been found to be components that degrade stability. On the other hand, the present inventors reported that Na ₂ O and K ₂ O
Has also been found to be a component having the effect of improving the bead encapsulation of slag and improving the slag removability.

[0014] On the other hand, as described in JP-A-58-70993, only the addition of SiO ₂ of more than 10 times the metal fluorides in the wire can be achieved a smooth droplet transfer Therefore, the amount of spatter generated cannot be sufficiently reduced. In other words, the inventors of the present application have found that in order to suppress the generation of spatter and reduce the amount of spatter, the stability and concentration of the arc are improved, and the formation of droplets at the tip of the wire during welding is performed. It was found that it was necessary to smooth a series of droplet transfer phenomena such as growth and detachment. Further, it was also found that when the SiO ₂ content was increased, the slag removability was reduced, and slag entrainment occurred.

Based on these findings, the present inventors further studied the flux components and their contents, and found that metal fluoride, TiO ₂ and Al ₂ O _{3 in the} flux were used.
And the Na ₂ O content and the K ₂ O content and the total amount thereof, and by containing SiO ₂ having a predetermined weight ratio with respect to the F content in the flux, stabilization of the arc. It has been found that the properties, concentration and droplet transferability are improved, and the amount of spatter generated can be reduced. Also, in the present invention, Na in the flux
₂ O content and K ₂ O content and with defining the total amount, because the flux is substantially free of ZrO _2,
Slag removability can be improved. Further, if one or both of the outer shell and the flux contain one or both of the N and nitrogen compounds, the content is defined, and the flux does not substantially contain a metal carbonate. The amount of spatter generated can be further reduced.

The reason why the composition of the flux contained in the outer shell of the flux-cored wire for welding austenitic stainless steel according to the present invention is described below.

Metal fluoride (F conversion value): 0.1 to 0.
5 wt% metal fluoride is a component having an effect of improving the porosity resistance of the wire. Further, since metal fluoride takes in electrons in an arc atmosphere and becomes a stable monovalent anion, the effect of improving the stability of the arc can be obtained by including the metal fluoride in the flux. . The present invention relates to a method for preparing predetermined amounts of TiO ₂ , SiO ₂ and Al ₂ O ₃
Is added to the flux and the K ₂ O content and N
The content of a ₂ O and the total amount thereof are regulated, and the amount of spatter generated can be reduced by the synergistic effect of these and the addition of metal fluoride. If the metal fluoride content in the flux is less than 0.1% by weight based on the total weight of the wire in terms of F, the porosity resistance and arc stability of the wire will deteriorate. On the other hand, if the metal fluoride (F-converted value) in the flux exceeds 0.5% by weight based on the total weight of the wire, the stability of the arc and the concentration of the arc are deteriorated, and the amount of spatter generated is significantly increased. Therefore, the metal fluoride in the flux is 0.1 to 0.5 in terms of F in terms of the total weight of the wire.
% By weight.

In the present invention, examples of the metal fluoride include NaF, K ₂ SiF ₆ , CeF ₃ and CaF ₂ , and these compounds can be added to the flux singly or in combination.

TiO ₂ : 2.6 to 8.5% by weight TiO ₂ is a component having an effect of improving droplet transferability. In the present invention, as described above, the flux contains T
Synergy between the effect of adding iO ₂ and the effect of adding a predetermined amount of metal fluoride, SiO ₂ and Al ₂ O ₃ to the flux and regulating the K ₂ O content and the Na ₂ O content and the total amount thereof The effect can reduce the amount of spatters generated. In addition, TiO ₂ in the flux has an effect of improving the bead encapsulation property of the slag and improving the bead shape. If the content of TiO ₂ in the flux is less than 2.6% by weight based on the total weight of the wire, the droplet transferability decreases, and the amount of spatter generated increases. If the content of TiO ₂ is less than 2.6% by weight based on the total weight of the wire, the bead encapsulating property of the slag decreases and the shape of the bead deteriorates. On the other hand, even if TiO ₂ in the flux exceeds 8.5% by weight based on the total weight of the wire, the bead encapsulation of the slag becomes unstable, the thickness of the slag becomes uneven, and the slag removability decreases. At the same time, the bead shape deteriorates. Therefore, TiO ₂ in the flux is 2.
6 to 8.5% by weight.

In the present invention, raw materials of TiO ₂ include rutile, titanium white, illuminite, and titanates such as potassium titanate and calcium titanate. These may be used alone or in combination to form a flux. Can be added.

K ₂ O: 0.01% by weight or more and 0.10% by weight
%, Na ₂ O: 0.01% to 0.10% by weight
, Total content of K ₂ O and Na ₂ O: 0.15 weight
% Or less Both K ₂ O and Na ₂ O are components having an effect of improving bead encapsulation of slag and improving slag removability. The content of K ₂ O in the flux is less than 0.01% by weight based on the total weight of the wire, or the content of Na ₂ O
If the content is less than 0.01% by weight based on the total weight of the wire, the bead encapsulating property and the slag peeling property of the slag are reduced. On the other hand, when K ₂ O in the flux is 0.10% by weight or more based on the total weight of the wire, Na _{2 in} the flux
When the O content is 0.10% by weight or more based on the total weight of the wire, or when the total amount thereof is 0.1% by weight based on the total weight of the wire.
If it exceeds 5% by weight, the stability of the arc will deteriorate. Therefore, K ₂ O and Na ₂ O in the flux are not less than 0.01% by weight and less than 0.10% by weight, respectively, based on the total weight of the wire, and the total content of K ₂ O and Na ₂ O is the total weight of the wire. 0.15% by weight or less. Note that K
_As a raw material of ₂ O and a raw material of Na ₂ O, auxiliary components such as potassium titanate, soda feldspar, and potassium feldspar can be used.

Al ₂ O ₃ : 0.05 to 0.44% by weight Al ₂ O ₃ has the effect of improving the arc concentration and also increases the melting point of the slag to prevent the slag from flowing down, and to form a bead. Is a component that has the effect of improving
Al ₂ O _{3 in} flux is 0.05 per total weight of wire
When the content is less than the weight%, the arc concentration deteriorates and the bead shape deteriorates. On the other hand, Al in the flux
_{When 2} O ₃ exceeds 0.44% by weight based on the total weight of the wire,
The bead encapsulation and slag removability of the slag are significantly reduced. Therefore, Al ₂ O ₃ in the flux is 0.05 to 0.44% by weight based on the total weight of the wire. In the present invention, as a raw material of Al ₂ O ₃ , auxiliary components such as alumina, soda feldspar, and potassium feldspar can be used.

SiO ₂ : 0.7 to 5.5% by weight,
([SiO ₂ ] / [F]); 6.5 to 12.0 SiO ₂ is the metal fluoride, TiO ₂ ,
When K ₂ O and Na ₂ O and the total amount thereof and Al ₂ O ₃ are within the above-specified ranges, droplet transferability is remarkably smoothed,
It is a component having the effect of reducing the amount of spatter. This effect is due to the fact that SiO ₂ is added to the flux at a content of 6.5 to 12.0 times the metal fluoride content (F-converted value) in the flux, and that the content is It can be obtained when it is between 0.7 and 5.5% by weight per weight. The content of SiO _{2 in} the flux per weight of the wire in terms of% by weight [SiO ₂ ], the content of metal fluoride in the flux per weight of the wire (F-converted value)
Is [F] in weight%, ([SiO ₂ ] /
[F]) is less than 6.5 or more than 12.0, or the SiO ₂ content is less than 0.7% by weight or more than 5.5% by weight based on the total weight of the wire. In this case, the droplet transferability decreases, and the amount of spatter generation increases significantly. If ([SiO ₂ ] / [F]) exceeds 12.0 and the SiO ₂ content exceeds 5.5% by weight based on the total weight of the wire, slag seizure occurs and slag peeling occurs. Is reduced. Therefore, ([S
iO ₂ ] / [F]) is 6.5 to 12.0, and the SiO ₂ content is 0.7 to 5.5% by weight based on the total weight of the wire. In the present invention, the raw material of SiO ₂ includes silica sand, soda feldspar, potassium feldspar and the like, and these can be used alone or in combination.

ZrO ₂ : less than 0.10% by weight Since ZrO ₂ is a component that lowers the bead encapsulation property of the slag and the removability of the slag, ZrO ₂ in the flux
It is preferable to reduce the rO ₂ content as much as possible, and it is assumed that it is not substantially contained. In particular, Z in the flux
If the rO ₂ is 0.10% by weight or more based on the total weight of the wire, the slag removability decreases. Therefore, ZrO ₂ in the flux is less than 0.10% by weight based on the total weight of the wire.

In the present invention, excellent porosity resistance and good welding workability (reduction of spatter generation and improvement of slag removability) can be achieved by specifying the components in the flux and the contents thereof as described above. Although it can be obtained, if any one of these specified components is out of the range specified in the present invention, the effect cannot be obtained. If the total amount of one or both of N and nitrogen compounds in the wire and the content of the metal carbonate in the flux are appropriately adjusted, the amount of spatters generated can be further reduced. Hereinafter, the reasons for defining the contents of these components will be described.

The group consisting of N and nitrogen compounds in the wire
Total amount of one or two selected from the above (N-converted value): 0.0
05 to 0.090% by weight N is a component having an effect of reducing the particle diameter of the droplet.
Therefore, the effect of the addition of N and the addition of a predetermined amount of metal fluoride, SiO ₂ , TiO ₂ and Al ₂ O ₃ to the flux, as well as the K ₂ O content, the Na ₂ O content and the total amount are regulated. By the combined effect with the effect obtained by
The amount of spatter generated can be further reduced. The total amount of one or two selected from the group consisting of N and nitrogen compounds in the wire is 0.0
If it is less than 05% by weight, the above effects cannot be sufficiently obtained. On the other hand, if the total amount of one or two selected from the group consisting of N and a nitrogen compound exceeds 0.090% by weight based on the total weight of the wire in terms of N and is excessively contained in the wire, the slag peeling property is increased. Deteriorates. Therefore, one or two selected from the group consisting of N and nitrogen compounds in the wire
The total amount of the seed is 0.005 to 0.090% by weight in terms of N based on the total weight of the wire. In the present invention, N
One or both of the nitrogen compound and the nitrogen compound are contained in either or both of the outer sheath and the flux of the wire.
n.

Metal carbonate (CO ₂ equivalent): 0.05 weight
The metal carbonate in the flux less than the amount% generates CO gas by thermal decomposition during welding, thereby increasing the amount of spatter generated. Therefore, the metal carbonate in the flux should be reduced as much as possible. Preferably, it is not substantially contained. In particular, the metal carbonate in the flux is C
If the O ₂ conversion value is 0.05% by weight or more based on the total weight of the wire, the amount of spatters generated increases. Therefore, the content of the metal carbonate in the flux is less than 0.05% by weight based on the total weight of the wire in terms of CO ₂ .

In the present invention, the composition of the shell made of austenitic stainless steel and the composition of the flux components other than the above components are not particularly defined. Therefore,
These compositions can be variously adjusted in consideration of the chemical composition, mechanical performance, and welding workability of the deposited metal. In the present invention, the filling rate of the flux is not particularly limited. However, considering the stability of welding workability, the filling rate of the flux is preferably 21% by weight or more based on the total weight of the wire. Further, in order to prevent disconnection or the like at the time of wire production, the flux filling rate should be 3 per total weight of the wire.
It is preferably at most 1% by weight.

Further, there are various cross-sectional shapes of the flux-cored wire. However, the present invention is not particularly limited. As shown in FIG. can do.
That is, FIG. 1A shows a state in which the flux F is filled in a seamless metal outer shell M. FIG. 1 (b) shows that the metal shell M is bent into a tubular shape while filling the inside of the metal shell M with the flux F while abutting both edges of the metal shell M, and then drawn to a predetermined diameter. Things. Although the butt end face of this wire is flat, FIG.
Has a curved butted end face. FIG. 1 (c) shows the butt end portion bent in an L-shape to widen the butt end surface.

Further, the wire diameter may be, for example, 0.8, 0.9, 1.2 and 1.6 m depending on the application.
Wires of various diameters such as m can be arbitrarily selected. Furthermore, when welding is performed using the flux-cored wire of the present invention, a shielding gas such as CO ₂ gas or a mixed gas of Ar gas and CO ₂ gas can be used.

[0031]

EXAMPLES Examples of welding using the flux-cored wire for welding austenitic stainless steel according to the present invention will be specifically described below in comparison with comparative examples.

First, an outer skin made of austenitic stainless steel having the composition shown in Tables 1 and 2 below was prepared.
Filling the outer shell with flux having various compositions,
A flux-cored wire for welding austenitic stainless steel having a wire diameter of 1.2 mm was produced. The wire had the shape shown in FIG. 1D, and the flux filling rate was 21 to 31% by weight based on the total weight of the wire. Next, all the obtained wires were left in a normal air atmosphere (temperature: 20 to 28 ° C., humidity: 70 to 80%) for one week. Thereafter, the materials to be welded were welded using these wires, and the welding workability and the pore resistance were evaluated.

Table 3 shows the welding conditions used in the welding workability evaluation test. The welding workability was evaluated by observing arc stability, arc concentration, droplet transferability, spatter generation, bead encapsulation of slag, slag removability, and bead shape.

Table 4 below shows the welding conditions used in the test for evaluating the porosity, and FIG. 2 shows the welding method. As shown in FIG. 2, the wire 1 is held by a contact tip 5, which is arranged inside a cylindrical shield cup 4. Then, a shield gas is supplied to the welded portion from between the shield cup 4 and the contact tip 5 and welded by the wire 1. In the present embodiment, as the material to be welded,
Two copper plates 3 each having a thickness of 15 mm were separately arranged on a mild steel plate 2 having a thickness of 12 mm.
The copper plate 3 was formed with an inclined notch extending from the upper surface to the end surface of the copper plate 3, and the distance between the end surfaces of the copper plate 3 placed apart was 12 to 18 mm. And mild steel plates 2 and 2
The weld metal 6 was laminated in five layers and five passes with the wire 1 on the groove formed by the two copper plates 3, and the occurrence of pits and blow holes was observed to evaluate the porosity resistance.

The composition of each wire is shown in Tables 5 to 12 below, and the evaluation results are shown in Tables 13 to 16 below. Regarding arc stability, arc concentration, droplet transferability, bead encapsulation property of slag, and bead shape in the welding workability evaluation result columns shown in Tables 13 and 15 below, は means that it is good. Indicates that the product is defective. Regarding the amount of spatter generated and the slag peeling property, は indicates that it is very good (the amount of spatter generated is extremely small, and the slag peeling property is very good), and ○ indicates that it is good (the amount of spatter generated is small, Good peelability). Furthermore,
X shows that it is defective (a large amount of spatter is generated and the slag removability is poor). Tables 14 and 16 below
In the column of the evaluation results of the porosity resistance shown in the above, ○ indicates that no pits and blowholes were generated, and X indicates that pits or blowholes were generated.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

[0042]

[Table 7]

[0043]

[Table 8]

[0044]

[Table 9]

[0045]

[Table 10]

[0046]

[Table 11]

[0047]

[Table 12]

[0048]

[Table 13]

[0049]

[Table 14]

[0050]

[Table 15]

[0051]

[Table 16]

As shown in Tables 5 to 16 above, Example N
o. Nos. 1 to 20 were excellent in welding workability and porosity resistance because the composition of the flux was appropriately regulated. In particular, in Example No. In Nos. 1 to 14, since the N content (converted value) in the wire is within the preferable range of the present invention and the metal carbonate (CO ₂ converted value) is regulated to less than 0.05% by weight, spatter The amount could be further reduced.

On the other hand, in Comparative Example No. In No. 21, since the TiO ₂ content in the flux is less than the lower limit of the range of the present invention, the transferability to welding decreases, the amount of spatters increases, the bead encapsulation of slag decreases, and the bead shape deteriorates. did. Comparative Example No. In No. 22, since the TiO ₂ content in the flux exceeded the upper limit of the range of the present invention, the bead encapsulating property and the slag peeling property of the slag were reduced, and the bead shape was deteriorated. Comparative Example No. 23 is Si in the flux
With O ₂ content is less than the lower limit of the range of the present invention,
Since ([SiO ₂ ] / [F]) was less than the lower limit of the range of the present invention, droplet transferability was reduced, and the amount of spatters generated was increased. Comparative Example No. In No. 24, since the SiO ₂ content in the flux exceeded the upper limit of the range of the present invention, the droplet transferability was reduced, the spatter generation amount was increased, and the slag peelability was reduced.

Comparative Example No. 25 is Al ₂ in the flux
Since the O ₃ content was less than the lower limit of the range of the present invention, the arc concentration and the droplet transferability were reduced, the spatter generation amount was increased, and the bead shape was deteriorated. Comparative Example No.
In No. 26, since the Al ₂ O ₃ content in the flux exceeds the upper limit of the range of the present invention, the solidification shrinkage (aggregation) of the slag was too fast, the bead encapsulation property was reduced, and the slag peelability was also reduced. . Comparative Example No. 27 is ZrO ₂ in the flux
Is contained outside the range of the present invention, so that the coagulation shrinkage (aggregation) of the slag is too fast, the bead encapsulation property is reduced, and the slag peelability is also reduced.

Comparative Example No. 28 is K ₂ O in flux
Since the content and the Na ₂ O content were less than the lower limits of the range of the present invention, the bead encapsulation property and the slag peeling property were reduced. Comparative Example No. 29 is the K ₂ O content in the flux and K ₂ O
Since the total of the content and the Na ₂ O content exceeded the upper limit of the range of the present invention, the stability of the arc was deteriorated, the droplet transferability was lowered, and the amount of spatters increased. Comparative Example No. In Nos. 30 and 31, ([SiO ₂ ] / [F]) was out of the range of the present invention, so that the droplet transferability was reduced and the amount of spatter generated was increased.

Comparative Example No. 32 is the total amount of metal fluoride (F
(Converted value) is less than the lower limit of the range of the present invention, so that the stability of the arc and the porosity were deteriorated. Also, in Comparative Example No. 3
In No. 2, since the metal carbonate in the flux is out of the preferred range of the present invention and ([SiO ₂ ] / [F]) is out of the range of the present invention, droplet transferability is reduced, Spatter generation increased. Comparative Example No. No. 33, since the total amount of metal fluoride exceeds the upper limit of the range of the present invention,
The arc stability, arc concentration, and droplet transferability decreased, and the amount of spatter generated increased. Comparative Example No. No. 34 shows that the SiO ₂ content in the flux is less than the lower limit of the range of the present invention, the K ₂ O content and the Na ₂ O content in the flux and the total amount thereof exceed the upper limit of the range of the present invention, Since the salt was outside the preferred range of the present invention, arc stability and droplet transferability were reduced, and the amount of spatter generated was increased. Comparative Example No. 35 is K ₂ O in flux
Content and Na ₂ O content, and Si in the flux
Since the O ₂ content was less than the lower limit of the range of the present invention, the bead encapsulation property and the releasability of the slag were reduced, the droplet transferability was reduced, and the spatter generation amount was increased.

Comparative Example No. 36 is TiO in flux
_{2 While the} content is less than the lower limit of the range of the present invention, ([S
Since (iO ₂ ] / [F]) exceeded the upper limit of the range of the present invention, the droplet transferability was reduced, the spatter generation amount was increased, and the slag peeling property was reduced. In addition, bead encapsulation of slag is reduced by the influence of TiO ₂ ,
The bead shape has deteriorated. Comparative Example No. In No. 37, the bead encapsulating property and the slag peeling property of the slag were lowered because ZrO ₂ in the flux exceeded the upper limit of the range of the present invention. Also, in Comparative Example No. 37 is ([SiO ₂ ] /
Since [F]) was less than the lower limit of the range of the present invention, droplet transferability was reduced, and the amount of spatters generated was increased.

Comparative Example No. 38 is TiO in flux
_{(2) Since the} content exceeds the upper limit of the range of the present invention, the bead encapsulation property, the slag releasability, and the bead shape of the slag decreased. Also, in Comparative Example No. No. 38 shows that the K ₂ O content and the Na ₂ O content in the flux and the total amount thereof exceed the upper limit of the range of the present invention. did. Comparative Example No. 39
Since Al ₂ O _{3 in} the flux is less than the lower limit of the range of the present invention and ZrO _{2 in} the flux exceeds the upper limit of the range of the present invention, the arc concentration is deteriorated and the bead shape is reduced. Along with the deterioration, the droplet transferability decreased, and the amount of spatter generated increased. Also, in Comparative Example No. 3
In No. 9, the bead encapsulation property and the slag peelability of the slag were reduced due to the effect of ZrO _{2 in} the flux. Comparative Example N
o. No. 40 shows that the TiO ₂ content in the flux is less than the lower limit of the range of the present invention, and the K ₂ O content and Na ₂ O content and the total amount thereof exceed the upper limit of the range of the present invention. And the amount of spatters generated increased. Also, in Comparative Example No. In No. 40, the bead encapsulation property and the slag removability of the slag were reduced because ZrO ₂ in the flux exceeded the upper limit of the range of the present invention.

[0059]

As described in detail above, according to the present invention,
Since the composition of the flux is appropriately defined, the austenitic stainless steel has excellent porosity resistance, can reduce the amount of spatter generated, and can improve the slag peeling property, and thereby has good welding workability. A flux cored wire for steel welding can be obtained. Further, when the total amount of N and nitrogen compounds in the wire is regulated and the content of the metal carbonate in the flux is regulated, the amount of spatters generated can be further reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a shape example of a flux-cored wire for welding austenitic stainless steel according to the present invention.

FIG. 2 is a schematic view showing a welding method for performing a pore resistance evaluation test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1; Wire 2; Mild steel plate 3; Copper plate 4; Shield cup 5; Contact tip 6; Weld metal M; Metal shell F; Flux

Claims (2)

[Claims] 1. A flux-cored wire comprising an austenitic stainless steel sheath filled with a flux, wherein the flux is 0.1 to 0.5 weight of metal fluoride (F conversion value) per total weight of the wire. %, Ti
O ₂ : 2.6 to 8.5% by weight, K ₂ O: 0.01% by weight
Or more and less than 0.10% by weight, Na ₂ O: 0.01 to less than 0.10% by weight, Al ₂ O ₃ : 0.05 to 0.4
4% by weight and SiO ₂ : 0.7 to 5.5% by weight, and the total content of the K ₂ O and the Na ₂ O is 0.1%.
When the content of SiO _{2 is} defined as [SiO ₂ ] in weight% and the content of the metal fluoride (F conversion value) in weight% as [F], the content is regulated to 5% by weight or less. SiO
₂ ] / [F]) is 6.5 to 12.0, and ZrO ₂ is regulated to less than 0.10% by weight based on the total weight of the wire. Cored wire. 2. The method according to claim 1, wherein one or both of the outer shell and the flux have a total amount of one or two selected from the group consisting of N and a nitrogen compound in terms of N as 0.005 to 0. _2. The austenitic stainless steel according to claim 1, wherein the metal carbonate in the flux is regulated to less than 0.05% by weight in terms of CO _{2 based on the} total weight of the wire. Flux-cored wire for steel welding.