JP2000117488A - Ni-BASED ALLOY FLUX-CORED WIRE - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Ni-based alloy flux cored wire which is excellent in MAG weldability of Ni steel and Ni-based alloy, small in defective weld, and excellent in hot crack resistance. SOLUTION: A shell is formed of a Ni-based alloy, the filling ratio of the flux is 10-30 wt.% to total weight of a wire, and the flux has the composition consisting of, by weight to the total weight of the wire, 2-10% Ti02, 0.1-3% SiO2, 0.1-2% Al1O3, 0.4-3% ZrO2, 0.01-0.4% in terms of Li, Na and K in total weight of at least one kind selected from the group consisting of Li, Na and K compounds, 1-25% metal in total, and 4-15% slug in total, and regulating P to be <=0.0l0%, S to be <=0.0l5%, Bi to be <=0.005%, and B to be <=0.003%. In addition, a compound of at least one kind of rare earth metal to be selected from a group consisting of Y, La and Ce is contained by 0.01-0.4% in terms of the rare earth metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an LNG tank or the like.
The present invention relates to a flux-cored wire for gas shielded arc welding of low-temperature steel containing 1% by weight or less of Ni or a Ni-based alloy used for nuclear power and petroleum / chemical equipment, and more particularly for Ar +
Excellent arc stability and concentration in so-called MAG welding using about 20% by weight of CO ₂ , welding defects such as poor fusion and slag winding are less likely to occur, spatter generation, slag encapsulation, slag N has excellent welding workability such as peelability and bead shape, and has excellent hot cracking resistance.
It relates to an i-based alloy flux cored wire.

[0002]

2. Description of the Related Art Gas shielded arc welding using a flux-cored wire has been recently expanded in application because it is more efficient than covered arc welding and TIG welding. Flux-cored wires have been widely used. This kind of gas shielded arc welding wire is disclosed in Japanese Patent Publication No. 4-52190,
98488 and JP-A-8-309583.

[0003]

However, in the above-mentioned prior art, welding defects such as poor fusion and slag winding are liable to occur due to lack of arc stability and concentration, and high temperature cracking of the weld metal often occurs. However, there is a disadvantage that the characteristics of gas shielded arc welding, which is highly efficient, cannot be sufficiently exhibited.

[0004] The present invention has been made in view of the above problems, and in MAG welding of Ni-containing steel and Ni-based alloy, excellent welding workability, few welding defects, and excellent hot cracking resistance. It is an object of the present invention to provide a Ni-based alloy flux-cored wire.

[0005]

SUMMARY OF THE INVENTION A Ni-based alloy flux-cored wire according to the present invention is a Ni-based alloy having a Ni-based alloy as a sheath.
In the base alloy flux-cored wire, the filling rate of the contained flux is 10 to 33% by weight based on the total weight of the wire, and the flux composition is
TiO ₂ : 2 to 10% by weight, SiO ₂ : 0.1 to 3% by weight, Al ₂ O ₃ : 0.01 to 2% by weight, ZrO ₂ :
0.4 to 3% by weight, at least one selected from the group consisting of Li, Na, and K compounds: 0.01 to 0.4% by weight in terms of the total amount of Li, Na, and K; 1 to 25% by weight, slag component: 4 to 15% by weight in total.

In this Ni-based alloy flux-cored wire, P is 0.010% by weight or less, S is 0.015% by weight or less, Bi is 0.005% by weight or less, and B is 0.1% by weight or less based on the total weight of the wire. It is preferable to regulate the content to 003% by weight or less.

Further, it is preferable that at least one rare earth metal compound selected from the group consisting of Y, La and Ce is contained in an amount of 0.01 to 0.4% by weight in terms of the total amount of the rare earth metal.

Further, it is preferred that the flux contains substantially no carbonate, and that the flux contains substantially no oxides of Fe and Mn.

[0009] result of extensive research and development in order to solve the above problems, the Ar concentration is high shielding gas atmosphere is particularly inert gases, greatly affected by flux containing, TiO ₂ -based, especially oxides It was found that ZrO ₂ was effective, but conversely, oxides of Fe and Mn were harmful. Further, it has been found that Y and rare earth metal components such as Li and Ce have an extremely large effect on the stability and concentration of the arc and are also effective on the crack resistance. The present invention has been made based on such findings.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The reasons for adding the components of the shell and flux and the reasons for limiting the composition in the present invention will be described below.

The Ni-based alloy is used as the outer skin metal in order not to impair the uniformity of the weld metal and to suppress the amount of alloy addition from the flux so that the flux is not overfilled. Ni-base alloys are Ni-Cr alloys, Ni
-Cr-Fe alloy, Ni-Cr-Mo alloy and the like. The shape of the outer skin may be either cylindrical or rectangular.

Flux filling rate The flux filling rate is 10 to 3 per the total weight of the wire.
3% by weight. The reason for setting the flux filling rate to 10% by weight or more is to secure a stable filling rate in the wire manufacturing process, secure a sufficient slag encapsulation at the time of welding, and obtain a sound weld metal. The reason why the flux filling rate is set to 33% by weight or less is to secure a uniform wire without disconnection or the like in the wire manufacturing process, and to deteriorate welding workability due to reduced concentration of arc, particularly welding defects such as slag entrainment. This is to prevent

Flux component (per total weight of wire) TiO ₂ : 2 to 10% by weight TiO ₂ is added as a main component of a slag forming agent having good arc stability and uniform encapsulation. TiO ₂ is these properties can not be obtained sufficiently less than 2 wt%, TiO ₂ in the opposite
If it exceeds 8% by weight, the slag adheres to the bead (seizure) and the releasability decreases. Examples of the TiO ₂ source include rutile, white titanium, calcium titanate, barium titanate, titanate, sodium titanate and the like.

SiO ₂ : 0.1 to 3% by weight SiO ₂ is a kind of slag forming agent like TiO ₂ .
It is added to increase the viscosity of the slag to improve the bead shape. If the content of SiO ₂ is less than 0.1% by weight, these properties cannot be sufficiently obtained. On the other hand, if the content is more than 3% by weight, the slag adheres to the bead (seizure) and the releasability decreases. SiO
_Two sources include wollastonite, quartz sand, mica, potassium feldspar or soda feldspar.

Al ₂ O ₃ : 0.01 to 2% by weight Al ₂ O ₃ is added to change the melting point of the slag and improve the fluidity. If the content of Al ₂ O ₃ is less than 0.01% by weight, these properties cannot be sufficiently obtained. On the other hand, if the content is more than 2% by weight, the encapsulating property of the slag decreases and the bead shape deteriorates. Al ₂
O ₃ sources include alumina, potassium feldspar or soda feldspar.

ZrO ₂ : 0.4 to 3% by weight ZrO ₂ is a kind of slag forming agent like TiO ₂ .
It has the effect of increasing the viscosity of the slag to improve the bead shape, but is particularly effective for arc stability. Zr
If O ₂ is less than 0.4% by weight, this effect is not obtained, and if it exceeds 3% by weight, the slag encapsulating property is reduced. Examples of the ZrO ₂ source include zircon sand and zircon flower.

Li, Na, K compounds: Li, Na, K exchange
Li, Na, and K in the total calculated value of 0.01 to 0.4% by weight have an effect of suppressing generation of spatter by adding one or more of them as an arc stabilizer. If the total amount of Li, Na, and K is less than 0.01% by weight, these characteristics cannot be sufficiently obtained.
Above, spatter increases. Li, Na, and K compound sources include LiF, NaF, KF, Na ₃ AlF ₆ , and K ₂ S
iF ₆ , soda feldspar or potassium feldspar.

Metal component: 1 to 25% by weight The metal component is added to deoxidize and obtain the desired deposited metal. Even if only a deoxidizer is used, at least 1% by weight is required.
Conversely, if the content exceeds 25% by weight, a sufficient amount of slag cannot be secured, and welding workability such as slag encapsulation and peelability deteriorates. Metal components include Ni, Cr, Mo, Nb, W, Si, Mn,
There are simple metal powders such as Al, Ti, Mg, and C or alloy powders.

[0019]Slag component: 4 to 15% by weight Slag components are non-metal components of metal oxides and metal fluorides
For the purpose of fine adjustment of arc characteristics and slag characteristics.
And add. If the total amount of slag components is less than 4% by weight,
Is not sufficiently covered, and the bead surface becomes rough. On the other hand,
If the lag component exceeds 15% by weight, the slag is excessive and
The slag disturbs and makes welding difficult. As a slag component
Is the aforementioned TiO_Two, SiO_Two, Al_TwoO_Three, ZrO_TwoOther
MgO, CaO, BaO, AlF_Three, CaF_Two, Ba
F_Two, MgF_Two, Na_ThreeAlF₆, K _ThreeAl₆Etc.

P, S, Bi, B: 0.010% by weight each
Below, 0.015% by weight or less, 0.005% by weight or less,
0.003% by weight or less P, S, Bi, and B are components that cause high-temperature cracking. Therefore, in order to obtain a sound weld metal, 0.010% by weight or less and 0.015% by weight, respectively, are required. % Or less, 0.0
It is preferable that the content be 0.05% by weight or less and 0.003% by weight or less.

Rare earth metal compounds of Y, La and Ce: Y,
The total amount of La and Ce converted to rare earth metal is 0.01 to
The rare earth metal composed of 0.4% by weight of Y, La, and Ce is stable and concentrated in an arc in a shielding gas atmosphere having a high concentration of an inert gas such as Ar (for example, 80% by volume Ar-20% by volume CO ₂ ). Since the spatter property is remarkably enhanced, the spatter is small, the bead shape is excellent, and it is effective to reduce poor fusion and slag entrainment.

Further, these metals are harmful to hot cracking.
To make it harmless and improve crack resistance.
You. The total amount of rare earth metal equivalents consisting of Y, La, and Ce
If the content is less than 0.01% by weight, these properties cannot be sufficiently obtained.
Conversely, when the content exceeds 0.4% by weight, spatter increases. others
A rare earth metal compound consisting of Y, La and Ce is
The total amount of La and Ce converted to rare earth metal is 0.01 to
It is preferable to add 0.4% by weight. Y, La, Ce
As a compound source, YF_Three, CeF_Three, Y_TwoO_Three, Ce
_TwoO_ThreeOr rare earth Ca-Si.

Carbonate: 0.03% by weight or less in terms of CO ₂
The lower carbonate is not actively added because it is decomposed in the arc to generate CO ₂ gas and spatter frequently occurs. In the present invention, “substantially not contained” means that it is not added as a carbonate simple substance raw material, but does not exclude the case where it is mixed as an unavoidable impurity of another raw material. However, even in this case, CO
_2, the total wire weight per 0.03 wt% or less in terms of.

Fe, Mn oxide: Fe ₂ O ₃ , MnO ₂ exchange
Calculated also respectively 0.05 wt% or less, Fe, Mn oxide is not added actively so encapsulated in the slag is poor. In the present invention, “substantially not contained” means that it is not added as a single raw material of Fe and Mn oxides, but it is not excluded when mixed as unavoidable impurities of other raw materials. However, even in this case,
_The content is 0.05% by weight or less based on the total weight of the wire in terms of ₂ O ₃ and MnO ₂ .

[0025]

EXAMPLES Table 1 below shows the composition of the Ni-based alloy skin. This outer skin was formed into a cylindrical shape by bending a band having a thickness of 0.4 mm and a width of 9 mm. After enclosing the flux shown in the following Tables 2 to 5 in this outer skin and drawing it to a diameter of 1.2 mm, it was heated to 400 pp with respect to the total weight of the wire by heating.
m so as to be a test wire.

As shown in FIG.
Performed with horizontal fillet using SM490A steel plate of 2 x width 80 x length 300mm, welding defect is JIS as shown in Figure 2.
A weld metal was prepared according to Z3332 and detected by X-ray transmission. The welding conditions were a current of 200 A and a voltage of 30 V, and Ar-20% CO ₂ (flow rate 25 l / min) was used as a shielding gas. The evaluation of welding workability was evaluated as ◎ for excellent, ○ for good, and × for poor. Regarding the evaluation of welding defects, JIS Z3104 grade 1 was accepted and this was evaluated as ○.

The hot cracking test was carried out at a thickness of 20 mm shown in FIG.
The test was carried out by a restraint cracking test method using a SM490A steel plate having a width of 125 mm and a length of 300 mm. Single bead welding was performed with an automatic welding machine, and the cracking rate (total crack length in the welding line direction / bead length) was calculated and evaluated. The welding conditions were a current of 200 A, a voltage of 30 V, a welding speed of 40 cpm, and a shielding gas of Ar-20% CO ₂ (flow rate 25 l / m 2).
in). The evaluation of the hot crack was evaluated as ◎ when the crack rate was 0% (no crack), ○ when the crack rate was less than 5.0%,
Those having a crack rate of 5.0% or more were rated as x.

The water content was measured by the Karl Fischer method (carrier gas: O ₂ , heating temperature: 750 ° C.).

[0029]

[Table 1]

In Table 1, the units of the outer coat components other than the components described in units (ppm) are% by weight. The composition of the components other than the chemical components described in Table 1 is O:
0.008% by weight, N: 0.010% by weight, H: 0.0
004% by weight, Co: 0.031% by weight, V: 0.12
% By weight.

The compositions of the test wires are as shown in Tables 2 to 5 below. In addition, Table 6 below shows the evaluation results of welding workability, welding defects (X-ray performance), and hot cracking.

As shown in Tables 2 to 6, the wire No. Examples 1 to 6 are examples satisfying claims 1 to 5 of the present invention, and all of the evaluations of welding workability, welding defects (X-ray performance) and hot cracking are excellent.

The wire No. 19 satisfies claim 1, but because the sum of rare earth metals such as Y, Ce and La exceeds the range of claim 3, welding defects (X-ray performance)
And hot cracking, the welding performance was excellent. Slightly worse than 1 to 6.

Wire No. 20 to 22 satisfy carbonate claim 1, but contain carbonate and Fe and Mn oxides and fall outside the scope of claim 4 or 5, so that any one of welding defects (X-ray performance) and hot cracking Although the evaluation was excellent, the welding workability was poor for the wire No. Slightly worse than 1 to 6.

Wire No. Although No. 27 satisfies Claim 1, the P exceeds the range of Claim 2, so that both the welding defect (X-ray performance) and the welding workability are excellent, but the hot cracking rate is slightly high. Inferior.

Wire No. 28 satisfies claim 1, but because S exceeds the range of claim 2, both the welding defect (X-ray performance) and the welding workability are excellent, but the hot cracking rate is slightly Inferior.

Wire No. No. 29 satisfies claim 1, but Bi is beyond the scope of claim 2, so that both the welding defect (X-ray performance) and the welding workability are excellent in evaluation, but the hot cracking rate is slightly Inferior.

Wire No. Although 30 satisfies claim 1, but B exceeds the scope of claim 2, the evaluation of welding defects (X-ray performance) and welding workability are both excellent, but the hot cracking rate is slightly higher. Inferior.

On the other hand, wire no. In No. 7, since TiO ₂ is less than the scope of claim 1 of the present invention, welding workability and welding defects (X-ray performance) are insufficient, and the bead shape is poor. Wire No. No. 8 has insufficient welding workability and poor bead shape because TiO ₂ is beyond the scope of claim 1 of the present invention.

Wire No. 9 because SiO ₂ is less than the range of the first aspect of the present invention, weldability and weld defects (X-ray performance) is bead-shaped with insufficient poor. Wire No. 10 is SiO _{2 according} to claim 1 of the present invention.
, Welding workability is insufficient and the bead shape is poor.

Wire No. Sample No. 11 has insufficient welding workability and welding defects (X-ray performance) and a poor bead shape because Al ₂ O ₃ is less than the scope of claim 1 of the present invention. Wire No. In No. 12, since Al ₂ O ₃ exceeds the range of claim 1 of the present invention, welding workability is insufficient and the bead shape is poor.

The wire No. In No. 13, since ZrO ₂ is less than the scope of claim 1 of the present invention, welding workability and welding defects (X-ray performance) are insufficient and bead shape is poor. Wire No. 14 is ZrO ₂ of the present invention.
, Welding workability is insufficient and the bead shape is poor.

The wire No. 15 and 16 are Li, Na, K
Is beyond the scope of claim 1 of the present invention, so that welding workability is insufficient. Wire No. 17 and 18 have flux ratios outside the scope of claim 1 of the present invention,
There is a problem in wire production, and welding workability and welding defects (X-ray performance) are insufficient.

Wire No. Since the sum of the components of slags 23 and 24 exceeds the scope of claim 1 of the present invention, welding workability is insufficient. Wire No. No. 25 has insufficient welding workability because the total of the metal components in the flux is smaller than the scope of claim 1 of the present invention. Wire No. 2
6 has less ZrO ₂ than the scope of claim 1 of the present invention;
Since the sum of the metal components in the flux exceeds the scope of claim 1 of the present invention, the welding workability is insufficient.

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

[Table 6]

[0050]

As described above, according to the present invention,
In MAG welding of Ni-containing steel and Ni-based alloy, welding workability can be improved, welding defects can be reduced, and occurrence of hot cracking can be prevented.

[Brief description of the drawings]

FIG. 1 is a view showing a test procedure for confirming the workability of horizontal fillet welding.

FIG. 2 is a view showing a dimensional shape of a groove for forming a weld metal;

FIG. 3 is a view showing a dimensional shape of a groove of a hot crack test plate.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C22C 19/05 C22C 19/05 B

Claims (5)

[Claims] In a Ni-based alloy flux-cored wire having a Ni-based alloy as an outer sheath, the filling rate of the contained flux is 10 to 33% by weight with respect to the total weight of the wire.
When the flux composition is TiO ₂ :
2 to 10% by weight, SiO ₂ : 0.1 to 3% by weight, A
l ₂ O ₃ : 0.01 to 2% by weight, ZrO ₂ : 0.4 to 3% by weight, at least one selected from the group consisting of Li, Na and K compounds: Total amount in terms of Li, Na, and K 0.01 to 0.4% by weight, metal component: 1 to 2 in total amount
5% by weight, slag component: Ni-based alloy flux cored wire containing 4 to 15% by weight in total. 2. P is 0.010 based on the total weight of the wire.
Wt% or less, S is 0.015 wt% or less, Bi is 0.0
The Ni-based alloy flux-cored wire according to claim 1, wherein the content of B is restricted to not more than 05% by weight and the content of B is restricted to not more than 0.003% by weight. 3. The method according to claim 1, wherein the compound contains at least one rare earth metal compound selected from the group consisting of Y, La and Ce in a total amount of 0.01 to 0.4% by weight in terms of rare earth metal. Item 7. A Ni-based alloy flux-cored wire according to Item 1. 4. The flux-cored Ni-based alloy wire according to claim 1, wherein the flux contains substantially no carbonate. 5. The Ni-based alloy flux-cored wire according to claim 1, wherein the flux contains substantially no oxides of Fe and Mn.