KR20070079579A - Ni-base alloy flux-cored wire - Google Patents

Abstract

A Ni-based alloy flux-cored wire for obtaining a welded metal that has excellent weldability in all postures and is excellent in high temperature cracking resistance, strength and low temperature toughness at the same time when welding 9% Ni steel is provided. In a Ni-based alloy flux-cored wire in which a flux is filled in a sheath of a Ni-based alloy, the Ni-based alloy flux-cored wire is characterized in that a deposited metal obtained by the flux-cored wire comprises 0.005 to 0.05 mass% of C, 0.1 to 0.5 mass% of Si, 0.2 to 6.0 mass% of Mn, 0.1 to 15.0 mass% of Cr, 10.0 to 25.0 mass% of Mo, 0.1 to 10.0 mass% of Fe, 1.0 to 4.0 mass% of W, 0.01 to 1.0 mass% of Ti, and the balance of Ni and inevitable impurities. The inevitable impurities is controlled to 0.020 mass% or less of P, 0.010 mass% or less of S, 0.1 mass% or less of Nb, 0.1 mass% or less of V and 0.1 mass% or less of Al. A mathematical expression 1 of 18.38-0.54x[Cr]<=[Mo]<=24.53-0.76x[Cr] is satisfied when contents of Cr and Mo of the deposited metal are [Cr] and [Mo] respectively. A value of the mathematical expression 2 of ([Na2O]+[K2O]+[Li2O]+0.2x[MnO])/([SiO2]+0.5x([Al2O3]+[TiO2]+[ZrO2])), is 0.5 or less when values of respective oxides converted from contents of respective compounds of Na, K, Li, Mn, Si, Al, Ti and Zr relative to the total wire weight that are contained in one or both of a filling flux and a Ni-based alloy sheath of the flux-cored wire are [Na2O], [K2O], [Li2O], [MnO], [SiO2], [Al2O3], [TiO2] and [ZrO2] respectively.

Description

Ni-based alloy flux cored wire {Ni-BASE ALLOY FLUX-CORED WIRE}

1 is a cross-sectional view showing the test plate shape used in the examples.

2 is a cross-sectional view showing a test plate shape used in Examples.

3 is a cross-sectional view showing a test plate shape used in Examples.

It is sectional drawing which shows the sampling position of each test piece used in the Example.

It is sectional drawing which shows the sampling position of each test piece used in the Example.

TECHNICAL FIELD The present invention relates to a Ni-based alloy flux cored wire having a Ni-based alloy as an outer shell, and in particular, a Ni-based group used for welding 9% Ni steel used in cryogenic containers such as liquefied natural gas tanks and chemical equipment. Alloy flux cored wire.

Ni-based alloy-based welding materials are applied to various welding methods such as TIG, MIG, and SMAW because the Ni-based alloy welding materials are remarkably superior in corrosion resistance and heat resistance compared to existing iron-based welding materials and stainless-based welding materials. In addition, since Ni-based alloy welding materials are excellent in heat resistance and corrosion resistance, as well as strength and toughness characteristics at cryogenic temperatures, welding construction of cryogenic tanks such as LNG (liquefied natural gas) made of 9% Ni steel is performed. It is applied to.

In addition, the recent progress in high efficiency of welding construction has led to the development of various flux cored wires, and the movement of introducing flux cored wires with the aim of increasing the efficiency of welding in the fields of cryogenic containers and chemical equipment. This is getting active. However, it cannot be said that the conventional Ni-based alloy flux cored wire satisfactorily satisfies the quality required when manufacturing tanks and pressure vessels used in cryogenic environments such as for LNG. For example, currently commercially available Ni-based alloy flux cored wires have a limited range of applications due to their limited crack resistance. In addition, the level of toughness demand for welds has recently increased and increased, and it is difficult to fully satisfy performance with conventional welding materials. Moreover, the flux cored wire which is excellent in the welding workability in all postures tends to lower mechanical performance, especially low-temperature toughness, and it is a problem that both welding workability and mechanical performance are large.

In order to improve the welding workability and crack resistance of the Ni-based alloy flux cored wire, various studies have been made. Ni-based alloy flux cored wires described in Japanese Patent Application Laid-Open No. 1997-309583, Japanese Patent Application Laid-Open No. 1999-197883, Japanese Patent Application Laid-Open No. 2000-343276, and Japanese Patent Application Laid-Open No. 2000-343277, The composition of the slag forming material is optimized to improve the weldability in all postures. In addition, the Ni-based alloy flux cored wire described in Japanese Patent Application Laid-Open No. 2005-59077 optimizes the chemical composition of the wire to improve the high temperature crack resistance.

However, the above-described prior art has a problem shown below. That is, Ni-based alloy flux cored wires described in Japanese Patent Application Laid-Open No. 1997-309583, Japanese Patent Application Laid-Open No. 1999-197883, Japanese Patent Application Laid-Open No. 2000-343276 and Japanese Patent Application Laid-Open No. 2000-343277. Both of them aim to improve welding workability, and there is a problem that the high temperature crack resistance of the weld metal is not sufficient.

In addition, the flux cored wire described in Japanese Patent Laid-Open No. 2005-59077 has a problem that welding workability in all postures is not sufficient.

The present invention has been made in view of the above problems, and in welding of 9% Ni steel, a Ni-based alloy flux core having a weld metal having excellent welding workability in all postures and excellent in high temperature crack resistance, strength and low temperature toughness can be obtained. It is an object to provide drawing wires.

The Ni-based alloy flux cored wire according to the present invention is a Ni-based alloy flux cored wire having a Ni-based alloy as an outer shell, wherein a weld metal component obtained by the flux cored wire is used.

C: 0.005-0.05 mass%,

Si: 0.1-0.5 mass%,

Mn: 0.2-6.0 mass%,

Cr: 0.1-15.0 mass%, Preferably 0.1-8.0 mass%,

Mo: 10.0-25.0 mass%, Preferably 15.0-25.0 mass%,

Fe: 0.1-10.0 mass%,

W: 1.0-4.0 mass%,

Ti: 0.01-1.0 mass%,

The balance is Ni and inevitable impurities.

As an unavoidable impurity, it is the following and is acceptable if it is the following ranges.

P: 0.020 mass% or less

S: 0.010 mass% or less

Nb: 0.1 mass% or less

V: 0.1 mass% or less

Al: 0.1 mass% or less

Moreover, when Cr value of a weld metal component is [Cr] and Mo value is [Mo], the following formula (1) is satisfied,

The content of each compound of Na, K, Li, Mn, Si, Al, Ti, and Zr with respect to the total weight of the wire contained in either or both of the filling flux of the flux cored wire and the Ni-based alloy shell is determined for each oxide. Are converted into [Na ₂ O], [K ₂ O], [Li ₂ O], [MnO], [SiO ₂ ], [Al ₂ O ₃ ], [TiO ₂ ] and [ZrO ₂ ], respectively. In doing so, the value of the following expression (2) is 0.5 or less.

The present invention is a Ni-based alloy flux cored wire used for welding 9% Ni steel, and after welding is performed on the groove surface to specify the wire, the welding filled in the groove by the main welding is performed. Define the composition of the metal (not affected by base metal dilution). When welding 9% Ni steel using Ni-based alloy flux cored wire, the obtained weld metal is affected by dilution of about 5 to 30% by mass, and the dilution rate at this time is the welding current, the welding voltage and the welding speed. It depends on the welding condition of and becomes large near the groove surface. Therefore, the chemical composition of the weld seam is strictly different from pass to pass. However, the welding material used for such a welding part can be evaluated by evaluating the characteristic of the weld metal which is not influenced by dilution. In order to test the composition of this weld metal, buttering was performed in this invention. That is, a layer (buttering layer) of the weld metal is grown using, for example, the Ni-based alloy flux cored wire or the same type of wire for welding on the slope of the V-groove and the upper surface of the backing metal. In the butterling layer, the components from the base material are mixed and diluted, but the influence of the base material is reduced by multilayer lamination, and when the three layers are laminated, the influence of the base material can be almost ignored. And after this buttering, the groove part enclosed by the buttering layer is main-welded using Ni-type alloy flux cored wire, and the inside of a groove is filled with a weld metal. The weld metal obtained by this main welding is not influenced by dilution of a base material. The present invention specifies the Ni-based alloy flux cored wire of the present invention by defining the composition of the weld metal. On the other hand, such buttering is not performed in a seal structure. Therefore, in the weld metal, there is dilution from the base metal, but as described above, the influence varies depending on the part even in the same groove, and the chemical composition is not the same. Therefore, although the performance of a weld metal is also considered not exactly the same in a weld metal, it can evaluate as a weld metal which is not influenced by dilution by evaluation of the welding material itself which welds these places. However, in the examples described later, the high temperature cracking sensitivity test was conducted by the Pisco crack test, but this is a part where the base material component is mixed into the weld metal by melting of the base material and is affected by the dilution by the base material component. It is performed on a specimen containing a. Thus, in this invention, the wire composition of this invention is prescribed | regulated in consideration of the influence by dilution of a base material.

The present inventors have conducted extensive experimental studies to solve the above-mentioned problems, and as a result, even when slag of low base degree such as high oxygen content of the weld metal is obtained, it is possible to secure good low-temperature toughness by optimizing Cr and Mo in alloy components of the weld metal. Found that it could.

Based on these findings, the present invention ensures welding workability in all postures as a slag system having a low base degree, and the composition of the weld metal falls within the above-mentioned range, thereby achieving welding workability in all postures and the resistance of the weld metal. The high temperature cracking property and the mechanical performance of a weld metal, especially low-temperature toughness are compatible. Thus, since it is based on the knowledge that the composition of the weld metal is closely related to characteristics such as low temperature toughness, it is more reasonable to include the composition of the weld metal rather than to define the invention only by the configuration of the wire itself. It was thought and used method to define in this way. If the scope of the invention is determined only by the configuration of the wire, the degree of freedom is excessively large, which is unreasonable.

Hereinafter, the Ni-based alloy flux cored wire according to the present invention will be described in detail. First, the composition of the weld metal formed by the wire of this invention is demonstrated.

"C: 0.005-0.05 mass% in the weld metal"

C has the effect of improving the strength of the weld metal. However, when the C content is less than 0.005%, the effect of improving the strength cannot be obtained sufficiently. On the other hand, when C content of a weld metal exceeds 0.05 mass%, high temperature crack resistance and toughness fall. Therefore, content of C is made into 0.05 mass% or less. On the other hand, as the C source in the deposited metal of the present invention, Ni-based alloy that forms the outer shell, the reduction from the CO ₂ gas and the slag component in the metal carbide, a shielding gas, such as Mn-C, Cr-C, WC included in the flux Is C.

"Si: 0.1-0.5 mass% in a weld metal"

Si has the effect of increasing the grain boundary strength of the weld metal and improving the ductility. However, the effect is not enough if Si content of a weld metal is less than 0.1 mass%. On the other hand, when Si exceeds 0.5 mass%, since it mix | blends with Ni and produces | generates a low melting-point compound, while deteriorating high temperature crack resistance, toughness also falls. Therefore, content of Si is made into 0.1-0.5 mass%. On the other hand, as a Si source of the weld metal in this invention, Ni group alloy which forms an outer skin, metal Si, Fe-Si alloy, etc. which are contained in a flux, or Si reduced from slag components, such as SiO.

"Mn: 0.2-6.0 mass% in a weld metal"

Mn forms a low melting point compound with Ni and combines with S which deteriorates high temperature crack resistance, thereby degrading S. However, when Mn content in a weld metal is less than 0.2 mass%, the effect of making S harmless is not acquired. On the other hand, when Mn content exceeds 6.0 mass%, slag peelability falls. Therefore, Mn content of a weld metal is 0.2-6.0 mass%. On the other hand, as the Mn source in the weld metal of the present invention, there are Ni-based alloys forming the outer shell, metals Mn contained in the flux, Fe-Mn alloys, MnO ₂ , MnCO _3, and the like. The amount of Mn can be adjusted.

"Cr: 0.1-15.0 mass% in a weld metal, Preferably 0.1-8.0 mass%"

Cr has the effect of improving the strength of the weld metal, but if it is less than 0.1% by mass, the effect is not. If the amount of Cr in the weld metal exceeds 15.0% by mass, the toughness decreases. Therefore, Cr content in a weld metal is 15.0 mass% or less. More preferably, Cr content is 0.1-8.0 mass%. On the other hand, examples of the Cr source in the weld metal of the present invention include a Ni-based alloy forming the shell, a metal Cr contained in the flux, a Fe-Cr alloy, Cr ₂ O _3, and the like. Cr amount can be adjusted.

"Mo: 10.0-25.0 mass% in a weld metal, Preferably 15.0-25.0 mass%"

Mo has the effect of improving the strength of the weld metal. However, when Mo content of a weld metal is less than 10.0 mass%, the strength of a weld metal cannot be ensured. On the other hand, when Mo content exceeds 25.0 mass%, the toughness of a weld metal will fall. Therefore, Mo content is made into 10.0-25.0 mass% per wire total mass. On the other hand, More preferably, Mo content is 15.0-25.0 mass%. On the other hand, the Mo source in the weld metal of the present invention includes a Ni-based alloy forming a shell, a metal Mo and a Fe-Mo alloy included in the flux, and the amount of Mo of the weld metal can be adjusted by addition of any of them. have.

"Fe: 0.1-10.0 mass% in a weld metal"

Fe is added to ensure ductility of the weld metal. When Fe content is less than 0.1 mass%, this effect cannot fully be ensured. On the other hand, when Fe content of a weld metal exceeds 10.0 mass%, the high temperature crack resistance of a weld metal deteriorates. Therefore, Fe content in a weld metal is 10.0 mass% or less. On the other hand, the Fe source in the weld metal of the present invention includes a Ni-based alloy forming a shell, a metal Fe contained in the flux, a Fe-Mn alloy, a Fe-Cr alloy, a Fe-Mo alloy, and a Fe-Ti alloy. The amount of Fe can be adjusted by adding any of them.

"W: 1.0-4.0 mass% in a weld metal"

W is a component that improves the strength of the weld metal. However, when W content in a weld metal is less than 1.0 mass%, the strength of a weld metal cannot be ensured. On the other hand, when W content exceeds 4.0 mass%, the toughness of a weld metal will fall. Therefore, W content in a weld metal is made into 1.0 to 4.0 mass%. On the other hand, as a W source in the weld metal of this invention, there are the Ni-based alloy which forms an outer shell, the metal W contained in a flux, Fe-W alloy, WC, etc., W can be adjusted by addition of any. .

"Ti: 0.01-1.0 mass% in a weld metal"

Ti is a component which is effective as a deoxidizer of a weld metal, but when the Ti content in the weld metal is less than 0.01% by mass, the deoxidation effect cannot be sufficiently secured. On the other hand, when Ti content exceeds 1.0 mass%, the toughness of a weld metal will fall. Therefore, Ti content is made into 0.01-1.0 mass% per wire whole quantity. On the other hand, the Ti source in the weld metal of the present invention includes Ti reduced from slag components such as TiO _2, such as Ni-based alloys forming the shell, metal Ti and Fe-Ti alloys contained in the flux.

`` Inevitable impurities ''

Inevitable impurities include P, S, Nb, V, and Al. These impurities are acceptable as long as they are within the following regulatory ranges.

P: 0.020 mass% or less in a weld metal

S: 0.010 mass% or less in a weld metal

Nb: 0.1 mass% or less in the weld metal

V: 0.1 mass% or less in a weld metal

Al: 0.1 mass% or less in a weld metal

P and S are unavoidable impurities present in the flux cored wire. Since P and S combine with Ni to produce a low melting point compound, high temperature crack resistance falls. Therefore, content of P and S is regulated to P: 0.020 mass% or less and S: 0.010 mass% or less, respectively.

Nb and V are unavoidable impurities present in the flux cored wire. Nb and V combine with Ni to produce a low melting point compound, resulting in a decrease in high temperature crack resistance. Therefore, content of Nb and V in a weld metal is regulated to 0.1 mass% or less, respectively.

Al is an inevitable impurity present in the flux cored wire. Ni-based alloy that forms the outer shell, but by a reduction from slag components such as Al ₂ O ₃ mixed in the deposited metal, if the Al content in the weld metal exceeds 0.1% by mass deteriorates the toughness. Therefore, Al amount in a weld metal is regulated to 0.1 mass% or less.

"When Cr value of a weld metal component is [Cr] and Mo value is [Mo], the following formula (1) is satisfied.

Equation 1

MEANS TO SOLVE THE PROBLEM This inventor produces nine types (No. 1-9) of flux cored wires from which the chemical component shown in an Example differs in Cr: 0.1-15.0 mass%, Mo: 10.0-25.0%, and is a weld metal. Tensile strength and impact value at -196 ° C were investigated. When the test result was subjected to multiple regression analysis of Cr and Mo and calculated by passing 690 MPa or more as the tensile strength and 70 J or more as the impact value at -196 ° C, the above formula 1 is satisfied. A tensile strength of 690 MPa or more and an impact value of 70 J or more at −196 ° C. were obtained. If [Mo] is less than 18.38-0.54 [Cr], the tensile strength is less than 690 MPa, resulting in insufficient tensile strength. In addition, when [Mo] exceeds 24.53-0.76 [Cr], the impact value at -196 ° C is less than 70 J, resulting in insufficient toughness.

The value obtained by converting the content of compounds of Na, K, Li, Mn, Si, Al, Ti, and Zr containing either or both of the filling flux of the flux cored wire and the Ni-based alloy shell into [Na ₂ O], [K ₂ O], [Li ₂ O], [MnO], [SiO ₂ ], [Al ₂ O ₃ ], [TiO ₂ ] and [ZrO ₂ ] 2 has a value of 0.5 or less

Equation 2

Equation 2 shows the basicity of the flux. When the basicity of the flux decreases, the melting point and viscosity of the molten slag are increased, and the workability of the posture welding is improved. However, when the salt airway (Equation 2) exceeds 0.5, the viscosity of the molten slag becomes low, and the weld metal during welding is liable to sag in the vertical direction or the like, and is not suitable for full posture welding. Therefore, basicity represented by Formula (2) is 0.5 or less. Examples of the Li, K and Na compounds include LiF, NaF, KF, Na ₃ AlFe, K ₂ SiFe ₆ , soda feldspar, Kali-feldspar, Li-Fe, etc., and TiO sources include rutile, white titanium and titanic acid. Potassium, sodium titanate, and the like Ti, Fe-Ti, Ti in the outer shell Ni-based alloy, etc., SiO ₂ source, such as silica, silica, mica, mica, soda feldspar, Calizite, Fe-Si, shell Ni There are Si in the base alloy, and ZrO ₂ sources include zircon sand and zircon flowers, and Al ₂ O ₃ sources include alumina, Fe-Al, Al-Mg and the like.

`` The content of compounds of Na, K, Li, Mn, Si, Al, Ti, and Zr with respect to the total weight of the wire contained in either or both of the filling flux of the flux cored wire and the Ni-based alloy shell is converted to each oxide. Convert the converted values into [Na ₂ O], [K ₂ O], [Li ₂ O], [MnO], [SiO ₂ ], [Al ₂ O ₃ ], [TiO ₂ ] and [ZrO ₂ ], respectively. At a total of one or two or more of [Na ₂ O], [K ₂ O], and [Li ₂ O] based on the total mass of the wire ''

By adding at least one member selected from the group consisting of Li, Na and K as the arc stabilizer, the arc is stable and there is an effect of suppressing the occurrence of sputtering. If the total amount of [Na ₂ O], [K ₂ O], or [Li ₂ O] is less than 0.1% by mass, the effect of suppressing the occurrence of sputtering cannot be sufficiently obtained. If it exceeds 3.0% by mass, the arc becomes unstable and spattered. More turing. Therefore, the content of one or more selected from the group consisting of Li, Na, and K is preferably 0.1 to 3.0 mass% of [Na ₂ O], [K ₂ O], and [Li ₂ O].

"Mn compound: 0.5-10.0 mass% in conversion of [MnO] with respect to the wire total mass"

MnO ₂ is added to increase the fluidity of the slag and to improve the appearance of the beads. In addition, the metal Mn and Mn alloy added for alloy adjustment are also mixed in some slag by oxidation at the time of welding, resulting in the effect of increasing the fluidity of the slag and improving the appearance of the bead. If the amount of the Mn compound added is less than 0.2% by mass in terms of [MnO], the effect of improving the appearance of the beads cannot be sufficiently obtained. On the other hand, when the addition amount of a Mn compound exceeds 10.0 mass% in conversion of MnO, the coatability of slag will fall. Therefore, it is preferable to make the addition amount of a Mn compound into 0.5-10.0 mass% in conversion of MnO.

"Si compound: with respect to the total mass of the wire, [SiO _2] 0.1 to 3.0% by mass in terms of"

SiO ₂ is added to increase the viscosity of the slag and to improve the bead shape. When the addition amount of the Si compound is less than 0.1% by mass in terms of [SiO ₂ ], the effect of improving the bead shape cannot be sufficiently obtained. On the other hand, if the addition amount of Si compound exceeds 3.0% by mass in terms of SiO _2, the removability of the slag is lowered. Therefore, the content of the Si compound is preferably in the range of 0.1 to 3.0% by mass in terms of SiO _2.

"Al, Ti, Zr compound: the total mass of one or more wires for _{[Al 2 O 3], [} TiO 2], [ZrO 2] in terms of the amount of 5.0 to 12.0% by mass"

Al, Ti, and Zr compounds are added to increase the melting point of the slag and to improve the workability of the posture welding. Is Al, Ti, less than 5% by weight of one or two total species in terms of more than _{[Al 2 O 3], [} TiO 2], [ZrO 2] of the Zr compound, the encapsulated of the amount of slag is not enough slag Deteriorates. On the other hand, when 1, 2 or more types of [Al ₂ O ₃ ], [TiO ₂ ], and [ZrO ₂ ] in terms of Al, Ti, and Zr compounds exceed 12.0% by mass, slag winding defects are likely to occur. Thus, in terms of _{Al, Ti, [Al 2 O} 3] 1 or two or more of a Zr _{compound, [TiO 2], [ZrO} 2] it is preferably set to 5.0 to 12.0% by weight total.

In addition, it is preferable to make Mo content and W content of the Ni-based alloy shell to be used into the following range.

"Mo: 10-25 mass%, W: 1-4 mass%"

Mo and W are indispensable elements in order to secure the strength of the weld metal, but in the case where the Mo and W content in the shell is small, insufficient portions must be added to the flux. When Mo and W are added to the flux, metals Mo and W are usually used. However, since the metals Mo and W have a high melting point, they are likely to melt and remain defective during welding, and therefore addition from the shell is preferable.

About the flux rate of the flux cored welding wire of this invention, it is possible to design a wire in the flux rate of 10% or more.

Example

Hereinafter, the strength, impact value, high temperature crack resistance, and welding workability at all postures of the weld metal of the embodiment of the present invention will be described in comparison with the comparative examples which deviate from the scope of the present invention. First, a band of thickness 0.4 mm and width 9.0 mm made of a Ni-based alloy having the composition shown in Table 1 was bent to produce a cylindrical shell (No. A to C). Flux cored wires (Nos. 1 to 25) containing fluxes composed of metal raw materials and slag components were prepared in these shells. The composition of this flux is as Table 3 below. In Table 3, the column of B is the value of general formula (2), and is the basicity of the flux. After wire-drawing this wire so that it might be set to 1.2 mm in diameter, it was set as the test wire which made the moisture contained in a wire into 400 ppm or less by heating. The composition of the weld metal obtained by welding using this flux cored wire is wire No. 1 to 25 and shell No. According to A-C, it became what is the electrodeposition metal component composition shown in following Table 2. However, although not shown in Table 2, all V was less than 0.01 mass%.

In addition, in each Example and the comparative example, the flux rate was 23 to 33%. The flux of each Example and a comparative example contains the metal component, fluoride, etc. which are normally used for the flux cored welding wire besides the component shown in Table 3.

And No. manufactured by the method mentioned above. For the wires of 1 to 25, the Pisco crack test was performed as the evaluation of weld workability in the vertical, the chemical composition analysis of the weld metal, the tensile and impact test, and the high temperature crack test.

As shown in Fig. 1, the evaluation of weld workability in the vertical direction was performed by adjusting the base material having the groove portion having the sloped surface such that the plate thickness was 12 mm and the groove angle was 55 ° such that the root gap of the groove was 2 mm. It carried out by welding in an upward position. The composition of this base material is shown in Table 4 below. The welding conditions of time, the welding current 150A, and voltage is 27V, the shield gas is a flow rate of using the Ar-80% CO _2, and the shielding gas was a 25ℓ / min.

As shown in FIG. 2, as shown in FIG. 2, the inclined surface was formed in the groove surface of SM 490 steel plate with a plate thickness of 20 mm so that the groove angle might be 45 degrees, and the buttering layer 2 was formed using this groove as a test wire. . Then, the buttered base material 1 was arrange | positioned so that root gap might be 12 mm, and the base metal 3 (steel material) which buttered the same surface was arrange | positioned on the narrow groove side. The grooves were welded to the grooves in accordance with JIS Z32222 to create a weld metal. Chemical composition analysis test and tensile test specimens (JIS Z3111 A test specimens 4 and 5 were taken. The welding conditions at this time were 200 A of welding current, 29 V of voltage, 300 to 400 mm of welding speed, and 80% Ar as shield gas. -20% CO ₂ was used, and the shield gas flow rate was 25 L / min.

The tensile strength was 690 MPa or more, the elongation was 30% or more, and the impact value at -196 ° C was 70 J or more.

In the high temperature crack resistance test, using a base material of the components shown in Table 4, as shown in Fig. 3, the plate thickness is 20 mm, the width is 125 mm, the length of which the slope is formed to half the plate thickness so that the groove angle is 60 °. The base material having a diameter of 300 mm was adjusted to have a gap of 2 mm, and the test piece was carried out by the restraint crack test method. Single bead welding by an automatic welding machine was performed, and the presence or absence of the crack which generate | occur | produced in the weld metal part except start and crater was confirmed.

On the other hand, the welding conditions of the high temperature crack test were 280 A for current, 34 V for voltage, 50 cm / min for welding speed, 80% Ar-20% CO ₂ for shield gas, and the flow rate of the shield gas was 25 l / min. .

The results are shown in Table 5 below.

As shown in Table 5, Example No. within the scope of the present invention. 1 to 6 were able to obtain good results with respect to the vertical welding workability, mechanical performance and high temperature crack resistance. Comparative Example No. 7, 8 and 17 had toughness deteriorated because Mo of the weld metal exceeded 24.53-0.76 x [Cr]. Comparative Example No. As for 9-11, Mo of the weld metal was less than 18.38-0.54 * [Cr], and tensile strength deteriorated. Comparative Example No. 11, the elongation deteriorated because Si of the weld metal was less than 0.1 mass%. Comparative Example No. Since C of the weld metal exceeds 0.05 mass%, toughness and crack resistance deteriorated. Comparative Example No. Since the Si of the weld metal exceeded 0.5 mass%, toughness and crack resistance deteriorated. Moreover, since the amount of Si compound with respect to the wire total mass exceeds 3.0 mass% in conversion of oxide, the slag peelability at the time of welding deteriorated. Comparative Example No. Since Mn of the weld metal exceeds 6.0 mass%, the slag peelability at the time of welding deteriorated. Moreover, since the amount of Mn compound with respect to the wire total mass exceeds 10.0 mass% in conversion of oxide, the slag coatability at the time of welding deteriorated. Comparative Example No. Since 15 of P of the weld metal exceeds 0.02 mass%, crack resistance deteriorated. Comparative Example No. Since S of the weld metal exceeded 0.01 mass%, the crack resistance fell by 16. Comparative Example No. Since 17 of Cr of the weld metal exceeded 15.0 mass%, toughness deteriorated. Comparative Example No. Since 18 of Mo of the weld metal exceeds 25.0 mass%, toughness deteriorated. Comparative Example No. Since 19b of Nb of the weld metal exceeds 0.1 mass%, crack resistance deteriorated. Comparative Example No. Since 20 of Fe of the weld metal exceeded 10.0 mass%, crack resistance deteriorated. Comparative Example No. Since 21 of the weld metal was less than 1.0 mass%, the tensile strength deteriorated. Comparative Example No. Since 22 of the weld metal exceeds 4.0 mass%, toughness deteriorated.

Comparative Example No. Since 23 of Al of the weld metal exceeds 0.1 mass%, toughness deteriorated. Comparative Example No. Since Ti of the weld metal exceeds 1.0 mass%, toughness deteriorated. In addition, since the total amount of Li, Na, and K compounds with respect to the total weight of the wire was less than 0.1% by mass in terms of oxide, spattering occurred at the time of welding. Comparative Example No. 25, since the total amount of Li, Na, and K compounds with respect to the total weight of the wire exceeded 3.0% by mass in terms of oxide, the arc became unstable and spattering occurred frequently. Comparative Example No. 14 and 25 are values of Na, K, Li, Mn, Si, Al, Ti, and Zr in terms of the total weight of the wire, respectively. [Na ₂ O], [K ₂ O], [ When Li ₂ O], [MnO], [SiO ₂ ], [Al ₂ O ₃ ], [TiO ₂ ] and [ZrO ₂ ], ([Na ₂ O] + [K ₂ O] + [Li ₂ O] + 0.2 × [MnO]) / ([SiO ₂ ] + 0.5 × ([Al ₂ O ₃ ] + [TiO ₂ ] + [ZrO ₂ ])) exceeds 0.5, deteriorating vertical workability .

In addition, Example No. Since the total amount of Ti, Zr, and Al compounds with respect to the total wire weight exceeded 12.0 mass% in oxide conversion, slag winding generate | occur | produced 2, but the mechanical property was a level with no problem. Example No. 5, the total amount of Ti, Zr, Al compounds relative to the total weight of the wire is less than 5.0% by mass in terms of oxide, the slag coatability is lower than in other examples.

According to the present invention, the welding workability at all postures is ensured as a slag system having a low base degree, and the composition of the welding metal is kept within the above-mentioned range, so that the welding workability at all postures and the high temperature crack resistance of the welding metals and the welding metals are obtained. Mechanical performance, especially low temperature toughness.

Claims (5)

In a Ni-based alloy flux cored wire in which a flux is filled in a Ni-based alloy shell, The weld metal component obtained by this flux cored wire C: 0.005-0.05 mass%, Si: 0.1-0.5 mass%, Mn: 0.2-6.0 mass%, Cr: 0.1-15.0 mass%, Mo: 10.0-25.0 mass%, Fe: 0.1-10.0 mass%, W: 1.0-4.0 mass%, Ti: 0.01-1.0 mass%, The balance is Ni and inevitable impurities, This inevitable impurity P: 0.020 mass% or less, S: 0.010 mass% or less, Nb: 0.1 mass% or less, V: 0.1 mass% or less, Al: 0.1 mass% or less Regulated by When Cr content of a weld metal component is [Cr] and Mo content is [Mo], the following formula (1) is satisfied, and The content of each compound of Na, K, Li, Mn, Si, Al, Ti, and Zr with respect to the total weight of the wire contained in either or both of the filling flux of the flux cored wire and the Ni-based alloy shell is determined for each oxide. Are converted into [Na ₂ O], [K ₂ O], [Li ₂ O], [MnO], [SiO ₂ ], [Al ₂ O ₃ ], [TiO ₂ ] and [ZrO ₂ ], respectively. The Ni-based alloy flux cored wire, wherein the value of the following formula (2) is 0.5 or less. Equation 1

Equation 2

The method of claim 1, The value obtained by converting the content of each compound of Na, K, Li, Mn, Si, Al, Ti, and Zr contained in either or both of the filling flux of the flux cored wire and the Ni-based alloy shell to When [Na ₂ O], [K ₂ O], [Li ₂ O], [MnO], [SiO ₂ ], [Al ₂ O ₃ ], [TiO ₂ ] and [ZrO ₂ ], respectively, Wire total weight [Na ₂ O], [K ₂ O], [Li ₂ O]: 0.1 to 3.0 mass% in one kind or a total of two or more kinds thereof, [SiO ₂ ]: 0.1 to 3.0 mass%, [MnO]: 0.5 to 10.0 mass%, [Al ₂ O ₃ ], [TiO ₂ ], [ZrO ₂ ]: Ni-based alloy flux cored wire, characterized in that 5.0 to 12.0 mass% in one kind or two or more kinds thereof. The method of claim 1, The weld metal component Cr: 0.01-8.0 mass%, Mo: 15.0-25.0 mass% Ni-based alloy flux cored wire, characterized in that the. The method of claim 1, Ni-based alloy flux cored wire, characterized in that the outer shell contains Mo: 10 to 25% by mass. The method of claim 1, Ni-based alloy flux cored wire, characterized in that the outer shell contains W: 1 to 4% by mass.

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