KR101088212B1 - Flux-cored wire for stainless steel electro gas arc welding - Google Patents

Abstract

In a flux-containing wire for stainless steel electrogas arc welding in which a flux is filled in a sheath made of stainless steel, Cr: 22 to 28 mass%, Ni: 8 to 12 mass%, and Fe: 55 to 70 per total mass of the wire. It contains mass%, regulates C content to 0.06 mass% or less, N content to 0.05 mass% or less, Cr content [Cr], Mo content [Mo], Ni content [Ni], and C content [ C] and when N content is [N], ratio Eq (Cr) / Eq (Ni) of Cr equivalent Eq (Cr) and Ni equivalent Eq (Ni) computed respectively from following formula (1) and (2) is 2.0- 2.6.

[Equation 1]

Eq (Cr) = [Cr] + [Mo]

[Equation 2]

Eq (Ni) = [Ni] + 35 × [C] + 20 × [N]

By such a configuration, even when welding a very thick stainless steel sheet, a poor fusion and undercut does not occur in the improvement, and a weld metal having high strength and high toughness in a cryogenic environment can be obtained.

Description

Flux-containing wire for stainless steel electrogas arc welding {FLUX-CORED WIRE FOR STAINLESS STEEL ELECTRO GAS ARC WELDING}

The present invention is made of stainless steel, such as a rectangular member of a spherical tank of LNG (liquefied natural gas), which requires strength and toughness, and a vessel used for welding a structure requiring strength and toughness in a cryogenic environment. A flux-containing wire for gas arc welding.

Conventionally, stainless steel used for large structures, such as each member of a rectangular tank of LNG, used in a state exposed to the atmosphere, requires corrosion resistance, strength, and toughness in a cryogenic environment, and thus, a stainless steel thick plate having a thickness of about 20 mm or more. Is being used. Conventionally, the welding of such a stainless steel thick plate is performed by the manual arc welding method using an arc discharge rod, or the semi-automatic gas shield arc welding method in which the flux containing wire and shield gas are automatically supplied.

However, the construction by the coated arc welding method and the semi-automatic gas shielded arc welding method is a shipbuilding, bridge, and chemical storage tank using a thick plate made of mild steel and high tensile strength steel because the welding speed is low and the work efficiency of vertical welding is very low. For welding such as the above, an electrogas arc welding method capable of performing high-direction welding with high welding speed is used.

In the welding of an ultra-thick plate, since the improvement is deep, a weld part is easy to become a multilayer, and defects, such as slag winding and undercut, are easy to generate | occur | produce in this weld part. When slag winding occurs in a welded part, mechanical performances, such as the strength and toughness of a weld metal, deteriorate, and when undercut occurs, fatigue strength falls by stress concentration. For this reason, it is strongly required to make the construction by electrogas arc welding into 1 pass welding, and also when welding the ultra thick plate by 1 pass construction, melt | dissolution to an improvement part is favorable and a defect does not arise in a weld part. There is a strong demand for a flux-containing wire for electrogas arc welding in which a weld metal having sound and sufficient mechanical performance is obtained.

For example, Japanese Patent Application Laid-Open No. 11-138295 contains a slag agent containing TiO ₂ , SiO ₂ and a metal fluoride in a flux filled in a shell made of tubular stainless steel. By specifying the content of, stainless steel with good mechanical properties of the weld metal is possible because of high efficiency and stable melt welding in the orientation of the thick plate stainless steel, excellent welding workability, and no undercut and pitting. Flux-containing wires for electrogas arc welding are disclosed.

In addition, electrogas arc welding having a large heat input has a low cooling rate until the weld metal solidifies, and therefore, the structure of the weld metal tends to be relatively coarse. When the flux-containing wire for stainless steel arc welding used conventionally, such as the 308 system prescribed | regulated to JISZ3323, is used for electrogas arc welding, the strength and tensile strength fall largely by the coarse weld metal structure. According to the flux-containing wire for stainless steel electrogas arc welding disclosed in Japanese Patent Application Laid-Open No. 11-138295, 0.2% yield strength is obtained by adding N or a metal nitride to the shell and / or the filling flux and specifying the addition amount thereof. It is disclosed that problems such as pit generation or increase in sputter generation amount can be suppressed while securing.

However, the above-described prior art has the following problems.

When N is added to the flux containing wire for stainless steel electrogas arc welding, the toughness of the weld part in cryogenic environment will fall. The flux-containing wire for stainless steel electrogas arc welding described in Japanese Patent Application Laid-Open No. 11-138295 discloses that N or metal nitride is added to the shell and / or the filling flux in order to secure a 0.2% yield strength. It is-0.16 mass%, and since toughness falls in a cryogenic environment, it becomes unsuitable for welding of structures used in cryogenic environments, such as a tank for LNG.

Moreover, in the Example of Unexamined-Japanese-Patent No. 11-138295, the welding test using the SUS304 steel plate and SUS316 steel plate of 20 mm of thickness is disclosed, but in the welding of the stainless steel plate whose plate thickness exceeds 20 mm, Even if this flux containing wire for stainless steel electrogas arc welding is used, it is inevitable that fusion failure occurs in the improvement.

The present invention has been made in view of the above problems, and even when welding a very thick stainless steel sheet, it is possible to obtain a weld metal having a high strength and high toughness in a cryogenic environment without causing poor fusion and undercut in the improvement. It is an object to provide a flux containing wire for welding stainless steel electrogas arc.

The flux-containing wire for stainless steel electrogas arc welding according to the present invention is a flux-containing wire for stainless steel electrogas arc welding formed by filling a flux in a sheath made of stainless steel with Cr: 22 to 28 mass per wire mass. %, Ni: 8-12 mass%, CaF ₂ : 1.0-2.0 mass%, Fe: 55-70 mass%, C content is 0.06 mass% or less, N content is regulated to 0.05 mass% or less, Cr When the content is [Cr], the Mo content is [Mo], the Ni content is [Ni], the C content is [C] and the N content is [N], the Cr equivalents respectively calculated from the following equations (1) and (2) The ratio Eq (Cr) / Eq (Ni) of Eq (Cr) and Ni equivalent Eq (Ni) is 2.0 to 2.6.

Eq (Cr) = [Cr] + [Mo]

Eq (Ni) = [Ni] + 35 × [C] + 20 × [N]

Moreover, it is preferable that the said flux contains 1.5-2.5 mass% of slag aids per mass of wire. Here, the slag preparation includes all the raw materials involved in slag formation, except for the metal powder which is an alloy component of the weld metal such as Fe, Cr, Ni, and Mn among the flux components filled in the shell. Also included are ingredients added for stabilization purposes. CaF _{2 is} also contained as part of the slag aid. The form in which each component of the slag auxiliary agent exists as the flux component may be a compound such as an oxide, a fluoride, a carbonate, a silicate, a carbide, and a nitride.

In addition, the flux is preferably not less than TiO _2, SiO ₂ and ZrO ₂ at least one of containing and, CaF ₂ content of TiO _2, SiO ₂ and the ratio of the total of the ZrO ₂ content of 5.0.

According to the present invention, in the flux-containing wire for stainless steel electrogas arc welding, by containing Cr in the wire, the weld metal is strengthened while specifying the Cr content in the wire, thereby reducing the ductility and toughness. In addition, by restricting the contents of C and N, which are intrusion-type elements, in the austenitic stainless steel, it is possible to suppress a decrease in impact resistance and toughness under a low temperature environment. Furthermore, by specifying the distribution of Cr equivalents and Ni equivalents of the metal elements in the wire, the structure balance in the weld metal can be optimized, and the yield strength and tensile strength can be improved without reducing the toughness under ductility and low temperature environment. Flux-containing wire for stainless steel gas arc welding can be obtained which has excellent mechanical properties even when used for welding of structures to be used in cryogenic environments such as tanks.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the wire for electrogas arc welding, and FIG. 2 is a perspective view which shows the welding part of electrogas arc welding by the cross section of a part of a perpendicular direction and a horizontal direction.

As shown in FIG. 2, in electrogas arc welding, the backing metal 3 is provided in the improvement 6 between the base materials 5 in a oriented posture, and the slide copper plate 2 is installed in the worker side. And arc arcing between the weld metal 43 and the wire 11 while supplying the wire 11 to the improvement 6 by the welding torch 13. Shield gas is supplied to the weld part from the gas supply port 22 provided in the slide copper plate 2, and it can prevent air from invading in a welding atmosphere by covering the arc 12 and the weld part 4 by this shield gas. . The slide copper plate 2 slides up and down in accordance with the movement of the welded part 4, and in this slide copper plate 2, the cooling pipe 23 which distributes a cooling water is provided, and the cooling pipe 23 has water. The welding part 4 can be cooled through the slide copper plate 2 by circulating.

As shown in FIG. 1, the wire 11 consists of a tubular outer shell 11a and the flux 11b filled in the inner shell 11a. The outer shell 11a is made of a substrate made of the same metal as the base metal to be welded to stabilize the structure of the weld metal, improve mechanical properties such as strength, tensile strength and toughness, or improve chemical properties such as corrosion resistance. It is stainless steel containing components, such as C, Ni, Cr, Si, Mo. In addition to the components in the stainless steel of the shell 11a, these components such as C and Si are present as single particles or compounds in the flux 11b, and the shell 11a and the flux ( Supplied by both sides of 11b).

The flux containing wire for stainless steel electrogas arc welding of this invention contains Cr: 22-28 mass%, Ni: 8-12 mass%, and Fe: 55-70 mass% per wire total mass. Moreover, 0.06 mass% or less and C content which a wire contains are regulated to 0.05 mass% or less. In addition, when Cr content in a wire is [Cr], Mo content is [Mo], Ni content is [Ni], C content is [C], and N content is [N], Cr equivalent Eq (Cr) in a wire And when Ni equivalent Eq (Ni) is defined by the following Equations 1 and 2, the ratio Eq (Cr) / Eq (Ni) of Cr equivalent Eq (Cr) and Ni equivalent Eq (Ni) is 2.0 to 2.6.

[Equation 1]

Eq (Cr) = [Cr] + [Mo]

[Equation 2]

Eq (Ni) = [Ni] + 35 × [C] + 20 × [N]

In the welding part 4, the base material 5 and the wire 11 are melted by the heat input by an arc discharge, and the melting part 41 is formed. In addition to generating an arc atmosphere as a gas generating source, the flux 11b forms the welding slag 42 by the slag preparation contained in the flux, deoxidation refining in the melting part 41, replenishment of alloy components, and molten metal. To ease the quench. The slag 42 rising from the molten part 41 of the weld part 4 flows between the weld metal and the slide copper plate 2, covers the bead surface, blocks the atmosphere, and forms smooth weld beads. The flux containing wire for stainless steel electrogas arc welding of this invention contains 1.5-2.5 mass% of slag aids per mass of wire. In addition, this slag preparation includes all the raw materials which finally participate in slag formation except for the metal powder which becomes an alloying component of welding metals, such as Fe, Cr, Ni, and Mn among the flux components filled in an outer shell, Also included are ingredients added for the purpose of arc stabilization. The form in which each component of this slag preparation agent exists as a flux component may be compounds, such as an oxide, a fluoride, a carbonate, a silicate, a carbide, and a nitride.

The melting point of the weld metal of stainless steel is 1400-1500 degreeC, and it is about 100 degreeC lower than general mild steel. Therefore, in the electrogas arc welding of stainless steel, it is slow for the weld metal to start solidification, and the difference in timing at which the slag 42 and the molten portion 41 start solidification becomes larger than that of the mild steel. And when the slag component which rises from the melting part 41 cannot be received by the slag 42 which is starting solidification, the slag component will be wound up in the melting part 41, and this wound slag component will be removed. You will not be able to.

The inventors of the present invention focus on CaF ₂ as a component of slag crude material that lowers the melting point of slag to the melting point of stainless steel, and adjusts the CaF ₂ content in the wire, thereby welding the thick plate over 20 mm by electrogas arc welding. Also in this case, the inventors discovered that it is possible to form a beautiful weld bead without fusion failure and slag winding occurring in the welded portion, and thus the present invention was devised. Stainless steel electro gas arc welding flux cored wire according to the present invention, contains a CaF ₂ per total mass of wire 1.0 to 2.0% by weight. Moreover, although this invention relates to the flux containing wire obtained by making a hoop material of stainless steel into an outer shell, and filling a flux inside the hoop material, the wire which distinguishes a thin diameter from a large diameter according to the electric current range used for welding is used. The wire diameter of can be applied to the present invention as long as the wire diameter is 1.0 to 2.0 mm which is generally used in semi-automatic welding.

Hereinafter, the reason for numerical limitation in the wire composition of this invention is demonstrated.

`` Cr: 22 to 28 mass% ''

Cr forms a passivation film on the surface of the stainless alloy steel, thereby improving corrosion resistance to air or acid. In addition, since Cr has the effect of solid-solution strengthening with respect to iron, the addition of Cr improves the yield strength and tensile strength. In order to acquire the solid solution strengthening effect of the weld metal by addition of Cr, Cr content in a weld metal should be 20 mass% or more. Since the added Cr is diluted by melting of the base metal and oxidized and consumed as slag, the content of Cr to be dissolved in the weld metal is reduced. Therefore, the Cr content in the wire may be 22 mass% or more. On the other hand, when the Cr content in the wire exceeds 28% by mass, the ferrite structure in the weld metal is excessive and the ductility is reduced, or the intermetallic compound mainly composed of Fe and Cr precipitates in the weld metal and the toughness and ductility tend to decrease. Lose. Therefore, it is preferable that Cr content in a wire is 22-28 mass%, and is 22-26 mass%.

"Ni: 8-12 mass%"

Ni is an effective component for forming austenite in the solidified structure of the weld metal, and also improves the corrosion resistance of the weld metal against non-oxidizing acids. In the welding method in which the heat input amount to a weld part differs greatly by the plate | board thickness of the base material welded like electrogas arc welding, and the dilution rate of the base material in a molten part differs according to the change of heat input amount, Ni contained in a wire When the amount is smaller than the amount of Ni contained in the base material, the amount of Ni in the weld metal is smaller than that of the base material, so that the corrosion resistance of the weld metal is lower than that of the base material. When Ni content in a wire is less than 8 mass%, the amount of Ni in a weld metal will become less than a base material, and corrosion resistance will fall. On the other hand, when the Ni content in the wire exceeds 12% by mass, the balance between the ferrite and the austenite structure contained in the solidified structure of the weld metal may fluctuate greatly depending on the dilution rate of the base material, thereby stably obtaining the mechanical properties of the weld metal. There will be no. Therefore, Ni content in a wire is 8-12 mass%.

`` Fe: 55 to 70 mass% ''

Fe is the balance of the stainless steel containing Cr and Ni components mentioned above. The flux-containing wire for stainless steel electrogas arc welding of the present invention contains, in addition to Cr and Ni, slag aids, C, N, Mo, or unavoidable impurities. Therefore, Fe content in a wire is 55-70 mass%.

`` Ratio Eq (Cr) / Eq (Ni) with respect to Ni equivalent Eq (Ni) of Cr equivalent Eq (Cr): 2.0 to 2.6 ''

By specifying the ratio of Cr equivalent Eq (Cr) to Ni equivalent Eq (Ni) in the wire, the structure balance in the weld metal is optimized. Here, Cr equivalent in a wire corresponds to the component which promotes formation of the ferrite structure in a weld metal, and Ni equivalent corresponds to the component which promotes formation of the austenite structure in a weld metal. In the present invention, in consideration of the fact that the metal contained in the wire may be diluted by welding, the ferrite structure in the weld metal and the Ni equivalent by specifying the Cr equivalent and Ni equivalent contained in the wire by the following equations (1) and (2). The content ratio of austenite structure can be optimized, and the same strength and tensile strength as that of the base material can be obtained even in a weld metal with a large heat input such as electrogas arc welding. When the ratio of Cr equivalent in Ni to the equivalent of Ni in the wire is less than 2.0, the austenite structure in the weld metal increases, and the yield strength and tensile strength decrease. On the other hand, when the ratio of Cr equivalent in Ni to the Ni equivalent in wire exceeds 2.6, the ferrite structure in a weld metal will increase, and ductility and toughness will fall. Therefore, the ratio of Cr equivalents to Ni equivalents in the wire is 2.0 to 2.6.

[Equation 1]

Eq (Cr) = [Cr] + [Mo]

[Equation 2]

Eq (Ni) = [Ni] + 35 × [C] + 20 × [N]

`` C: 0.06 mass% or less ''

C is included in the sheath of the wire, the flux raw material and the lubricant applied to the wire surface. In addition, CO ₂ in the shield gas is reduced by arc discharge, and reduced C is taken into the weld metal. When C is added, it is dissolved in an austenitic stainless steel such as SUS304L and dissolved as an invasive element, and the strength and tensile strength of the weld metal increase, but Cr carbide starts to precipitate in the weld metal as the amount of the addition increases. , Toughness under low temperature environment is lowered. When content of C in a wire exceeds 0.06 mass%, impact resistance and toughness in a low temperature environment will fall remarkably. Therefore, it is preferable that content of C in a wire is 0.06 mass% or less, and 0.02 mass% or less.

`` N: 0.05 mass% or less ''

N is contained in the outer skin of the wire and the flux raw material. Like C, since N is a solid solution as the intrusion type element in austenitic stainless steel, the strength and tensile strength of the weld metal increase as the amount of N added increases, and the impact resistance and toughness under a low temperature environment are lowered. In addition, when the amount of N added is large, N of gas is released in the molten metal, whereby pore defects such as blow holes and pits are likely to occur. When the content of N in the wire exceeds 0.05%, the impact resistance and toughness under a low temperature environment are lowered, and pore defects are more likely to occur. Therefore, it is preferable that content of N in a wire is 0.05 mass% or less, and 0.03 mass% or less.

The flux-containing wire for electrogas arc welding of the present invention may contain Mo for the purpose of improving corrosion resistance in addition to Cr, Ni, Fe, C, and N described above. However, when Mo content in a wire exceeds 1.0 mass%, an intermetallic compound will precipitate in a weld metal, and the toughness of a weld part in low temperature environment will fall. Therefore, it is preferable that Mo content in a wire is suppressed to 1.0 mass% or less.

"Slag preparations total: 1.5-2.5 mass%"

Among the flux components contained in the wire, the slag preparation agent has an action of relieving deoxidation refining of the molten metal and rapid quenching of the molten metal while rising to the upper part of the weld metal in the state of melting by arc heat in electrogas arc welding. When the sum total of the slag preparation agent in a wire is less than 1.5 mass%, the above-mentioned effect cannot fully be acquired and a fusion defect will arise easily. On the other hand, when the total amount of slag aids in the wire exceeds 2.5% by mass, the generated slag becomes excessive, and the occurrence of slag shock and sputter due to arc discharge increases, so that the appearance of the beads tends to be damaged. In addition, since arc discharge tends to break in the middle, slag winding, pits, blow holes, etc. in the weld metal tend to occur. Therefore, the total amount of slag aids in the wire is 1.5 to 2.5 mass%.

`` CaF ₂ : 1.0 to 2.0 mass% ''

Among the slag preparations, CaF ₂ lowers the melting point of the slag to approach the melting point of stainless steel, and also has a function of suppressing defects such as slag filling occurring in the improvement even when welding stainless steel sheets of ultra-thick plates of about 60 mm, It is possible to obtain good welding workability and sound weld metal. The present inventors slag jojae in view of the content of, the CaF ₂ components contained in the first, the addition amount and Reviewing the addition ratio, the addition amount of CaF ₂ a good welding workability and sound by 1.0 to 2.0% It has been found that a weld metal can be obtained. If the content of CaF ₂ is less than 1.0% by mass, the effect of lowering the melting point of the slag is not sufficient, and slag winding and fusion defects are likely to occur, and the unevenly generated slag tends to damage the bead appearance. On the other hand, when the content of CaF ₂ exceeds 2.0% by mass, components such as SiO ₂ and TiO ₂ , which are the main components in the conventional flux, are insufficient, so that the high temperature viscosity of the slag decreases and the weld beads are uneven to the surface. In addition to this, slag peelability is lowered. Therefore, the content of CaF ₂ in the wire is 1.0 to 2.0% by weight. In addition, among the slag preparations included in the wire, TiO ₂ , SiO _2, and ZrO ₂ have the effect of increasing the flowability of the slag, but are dispersed and remaining as fine complex oxide inclusions in the solidified weld metal, thereby penetrating the weld metal. In a flaw detection test, it may be detected as a point-like defect. Therefore, it is preferable that the total content thereof is smaller than the content of CaF ₂ . If the content of CaF _{2 in} the wire is less than 5.0 in terms of the ratio of the total content of TiO ₂ , SiO ₂ and ZrO ₂ , the point defects detected in the penetration test are significantly increased. Therefore, the ratio of the sum total of TiO _2, SiO ₂ and ZrO ₂ content of CaF ₂ content in the wire is preferably not less than 5.0, more preferably at least 15.O.

[Example]

Hereinafter, the Example which shows the effect of the flux containing wire for electrogas welding of this invention is shown with a comparative example.

The wire which filled the flux with the hoop material which consists of SUS304L was manufactured, and the electrogas arc welding was performed using this wire. Table 1 shows the composition and dimensions of the plate material used for the production of this hoop material.

The base material uses a 50 mm thick plate made of stainless steel containing the components shown in Table 2, and arranges the V-shaped improvements of both thick plates faced with an improvement gap of 5 mm, and a ceramic backing metal is placed behind the base material. Placed. In addition, the angle of the V-shaped improvement between the opposite base materials was 20 °, and electro-gas arc welding was performed while supplying CO ₂ or Ar-20% CO ₂ as the shield gas to the V-shaped improvement. The welding apparatus was DC reverse polarity (DC-EP), and it set on the welding conditions of 400A-43V, and the flow volume of the shield gas was 35 L / min.

Flux having various compositions is filled in the hoop material having the composition shown in Table 1, and electrogas arc welding is performed on the base material shown in Table 2 as a test material of the flux-containing wire for electrogas welding of Examples and Comparative Examples. It was. And the weld metal welded using the wire of the Example and the comparative example WHEREIN: The longitudinal tensile test and the V notch Charpy impact test in -196 degreeC environment were done, and 0.2% yield strength, tensile strength, and absorption energy were measured. And when 0.2% yield strength was 280 [N / mm <2>] or more, tensile strength was 580 [N / mm <2>] or more, and absorption energy was 34 [J] or more, it determined with the item of each performance favorable. Table 3 shows the fact that all items are satisfied and that at least one item is not satisfied.

The integrity of the weld metal was evaluated by determining the appearance of beads, the presence of poor fusion and the presence of slag winding. As a result of visual evaluation, it was good that the bead appearance had no slag winding and smooth beads were formed. In addition, the presence or absence of a defect was judged by the X-ray permeation test from the size and number of a fusion defect and slag winding, and it was good that there existed no defect. About the determination result of the appearance of a bead, a fusion defect, and the presence or absence of slag, a favorable thing is shown in Table 3 as (triangle | delta) and a conventional thing as (triangle | delta).

Nos. 1 to 7, 9, 10, and 17 shown in Table 3 are examples that satisfy the essential requirements of the present invention. Examples Nos. 1 to 7, 9, 10, and 17 show the contents of Cr, Ni, CaF ₂ , C, and N in the wire, and the ratio of Cr equivalents to Ni equivalents satisfying the scope of the present invention. The strength was shown and good toughness which can be judged from absorbed energy was obtained.

No. 11 is a comparative example in which the Cr content in the wire is less than the scope of the present invention, and the effect of solid solution strengthening by adding Cr is not obtained. No. 12 is a comparative example in which the Cr content in the wire exceeds the range of the present invention, the tensile strength decreases due to excessive increase of the ferrite structure in the weld metal, and the toughness decreases due to precipitation of the intermetallic compound. No. 13 is a comparative example in which the ratio of Cr equivalents contained in the wires to the Ni equivalents is less than the range of the present invention, and the tensile strength decreases due to an increase in the austenite structure in the weld metal. In Comparative Example No. 14, the ratio of Cr equivalents contained in the wires to the Ni equivalents exceeded the range of the present invention, and the toughness decreased due to the increase of the ferrite structure in the weld metal. In Comparative Example No. 15, the C content in the wire exceeded the range of the present invention, and the toughness decreased. In the comparative example No. 16, content of N in the wire exceeded the range of this invention, and toughness fell.

In Examples Nos. 1 to 7, 9, 10, and 17, which satisfy the essential requirements of the present invention, Examples No. 1 to 6 have a beautiful bead appearance, in which the slag reinforcing material content in the wire satisfies the scope of the present invention. In the welding metal, slag winding and fusion failure did not occur. Although No. 7 satisfies the conditions of the present invention, since the ratio of containing CaF ₂ in the slag preparation is relatively small, it is an example in which the appearance of the beads becomes equivalent to the conventional one by the action of other components of the slag preparation.

In Example No. 8, the CaF ₂ content in the wire was less than the scope of the present invention, and the effect of lowering the slag melting point was not sufficiently obtained, so that the occurrence of poor fusion and the appearance of beads became equivalent to those of the prior art. No. 17 had a lot of CaF ₂ content in a wire, and the appearance of beads slightly deteriorated. No. 9 is an example in which the content of the slag aid in the wire is large, the generated slag becomes excessive, the appearance of the beads is damaged, and the slag winding is generated in the same manner as in the past. In No. 10, quenching of the weld zone was not alleviated due to the lack of slag, and a poor fusion occurred in the same manner as in the past.

1 is a cross-sectional view showing a wire for electrogas arc welding.

It is a perspective view which cuts out the welding part of electrogas arc welding in a perpendicular direction and a horizontal direction.

Explanation of symbols for the main parts of the drawings

2: slide copper plate 3: backing metal

4 welding part 5 base material

6: improvement 11: wire

11a: jacket 11b: flux

12: arc 13: welding torch

Claims (3)

A flux-containing wire for welding stainless steel electrogas arc formed by filling a flux with a stainless steel sheath, , Per total mass of wire Cr: 22 to 28% by weight, Ni: 8 to 12% by mass, CaF _2: 1.0 to 2.0 mass% and Fe: containing 55 to 70% by weight and C content is 0.06 mass% or less, N content is regulated to 0.05 mass% or less, When Cr content is [Cr], Mo content is [Mo], Ni content is [Ni], C content is [C], and N content is [N], Cr equivalent Eq (Cr) computed from following formula (1) ) And the ratio Eq (Cr) / Eq (Ni) of Ni equivalent Eq (Ni) calculated from Equation 2 below is 2.0 to 2.6. Flux-containing wire for stainless steel electrogas arc welding. [Equation 1] Eq (Cr) = [Cr] + [Mo] [Equation 2] Eq (Ni) = [Ni] + 35 × [C] + 20 × [N] The method of claim 1, Flux-containing flux for stainless steel electro-gas arc welding, characterized in that the flux contains 1.5 to 2.5% by mass of the slag aid per mass of the wire. The method of claim 1, The flux is TiO _2, SiO ₂ and ZrO ₂ at least one of containing and, CaF ₂ content of TiO _2, SiO ₂ and stainless steel electro gas arc welding flux, characterized in that not less than the ratio 5.0 of the total of the ZrO ₂ content Containing wire.

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