JP2003103394A - Wire filled with welding flux - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire filled with welding flux capable of disposing a conductive core wire without applying complicated working to a metallic skin. SOLUTION: The flux 3 is filled in the metallic skin 2. The conductive core wire 4 is disposed at the approximately center part of the flux 3 in a state of being not supported by the metallic skin 2. The content of metal powder of the flux is made to be 20-80 wt.%. The wt.% of the flux weight to the weight of unit length of the wire is made to be 6.5-30 wt.%. The wt.% of the conductive core wire to the weight of the unit length of the wire is made 1.5-15 wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flux-cored wire for welding.

[0002]

2. Description of the Related Art U.S. Pat. No. 6,153,847 uses a flux-cored wire for welding in which various kinds of flux are filled in a metal shell in order to improve mechanical properties, crack resistance, etc. of the weld metal. . Flux is a deoxidizer,
It is composed of a slag forming agent, an arc stabilizer, and metal powder. However, in such a wire, since an arc is generated between the metal skin and the material to be welded, the metal skin is melted first. Therefore, the central part of the flux is not sufficiently melted, and the arc tends to become unstable. As a result, there is a problem that spatter is likely to occur and welding workability is deteriorated. In particular, with a welding wire made of Ni or a Ni-based alloy, the melting point of Ni or a Ni-based alloy is lower than that of iron or the like, and thus such a problem was remarkable.
Further, since the flux-cored wire for welding is subjected to a process of rolling a band-shaped outer cover material into a cylindrical shape to form an outer cover, when the thickness of the outer cover is larger than a predetermined size, the rounding process cannot be performed into a cylindrical shape. Therefore, there is a limit in reducing the space that can be filled with the flux in the outer skin, and there is a problem that the flux content cannot be adjusted to a small extent. If the flux content is unnecessarily large, the weld metal is likely to crack due to impurities contained in the flux. Therefore, 73 of "Latest welding engineering (revised 2nd edition)" by Haruyoshi Suzuki, published by Corona Publishing Co., Ltd. in Japan in 1998.
As shown in the page, it has been proposed to dispose a conductive core wire 103 supported by a support portion 102a integrally formed with the metal outer skin 102 at a substantially central portion of the flux 101 (FIG. 5).
reference). In this way, when the conductive core wire 103 is arranged,
An arc is also generated between the conductive core wire 103 and the material to be welded, the melting of the flux 101 is promoted, and the arc is stabilized. Further, the space that can be filled with the flux 101 in the metal shell 102 can be made small, and the amount of the flux can be appropriately adjusted to suppress cracking of the weld metal.

[0003]

However, in the case of such a wire, in order to support the conductive core wire 103, a complicated process for forming the support portion 102a on the metal skin 102 is required, and the manufacturing is complicated. there were. In particular, when the diameter dimension is reduced to 2.0 mm or less, the complexity of manufacturing becomes larger.

An object of the present invention is to provide a flux-cored wire for welding in which a conductive core wire made of Ni or a Ni-based alloy can be arranged without complicated processing on a metal outer shell made of Ni or a Ni-based alloy. is there.

[0005]

The present invention is directed to Ni or N.
A flux-cored wire for welding in which a flux is filled in a pipe-shaped metal outer sheath made of an i-based alloy is targeted for improvement, and Ni or N is contained in the metal outer sheath together with the flux.
The conductive core wire made of an i-based alloy is arranged without being supported by the metal sheath, and the flux is used not only between the metal sheath and the material to be welded but also between the conductive core wire and the material to be welded. The metal powder is contained in an amount sufficient to reduce the electric resistance value between the metal sheath and the conductive core wire to the extent that an arc is generated. The term "without being supported by the metal skin" as used herein means, for example, a metal skin without being enclosed or locked while being connected to a part of the metal skin as shown in FIG. It means that they are substantially separated. If the metal sheath and the conductive core are partially in contact with each other, the conductive core is not supported by the metal sheath,
It is included in the present invention. In the present invention, the flux contains a metal powder in an amount capable of lowering the electrical resistance value between the metal sheath and the conductive core wire, thereby achieving electrical conduction between the metal sheath and the conductive core wire. . As a result, even if the conductive core wire is placed together with the flux in the metal shell without being supported by the metal shell, the conductive powder and the shielded wire are covered by the current flowing from the metal shell through the metal powder in the flux. An arc can be generated between the welding material and the welding material. Therefore, unlike the conventional case, it is not necessary to perform a complicated process for supporting the conductive core wire on the metal shell, and the wire can be easily manufactured. Especially the average outer diameter of the metal skin is 2.
This ease of production exerts a great effect when it is reduced to 0 mm or less.

In order to contain the metal powder in an amount capable of reducing the electric resistance value between the metal skin and the conductive core wire to the extent that an arc is generated even between the conductive core wire and the material to be welded, For example, 20-80 wt% of granular metal powder may be contained in the flux with respect to the flux. If the granular metal powder is used, there is an advantage that the metal powder can be dispersed and mixed in the flux substantially evenly. If the amount of the granular metal powder is less than 20% by weight, the electrical conductivity between the metal outer sheath and the conductive core wire due to the flux cannot be sufficiently increased, and the arc is generated between the conductive core wire and the object to be welded. Does not occur sufficiently. Therefore, the state of the arc becomes worse,
Sputtering easily occurs. On the other hand, when it exceeds 80% by weight, the required amount of non-metal flux such as arc stabilizer is reduced. Therefore, the state of the arc deteriorates, and spatter easily occurs.

If the weight% of the weight of the flux with respect to the weight of the unit length of the wire is 6.5 to 30% by weight, the effect of the flux can be enhanced and cracking of the weld metal can be suppressed. If it is less than 6.5% by weight, the effect of the flux for improving the mechanical properties and crack resistance of the weld metal cannot be obtained. If it exceeds 30% by weight, the impurities contained in the flux easily cause cracks in the weld metal. In addition, it becomes difficult to include the conductive core wire.

Further, when the weight% of the weight of the conductive core wire to the weight of the unit length of the wire is set to 1.5 to 15% by weight, the arc becomes stable and spatter is less likely to occur.
If it is less than 1.5% by weight, the arc is not sufficiently generated in the conductive core wire, so that the arc becomes unstable and spatter is easily generated. If it exceeds 15% by weight, the amount of flux is limited, and the required amount of non-metallic flux such as arc stabilizer is reduced. Therefore, the state of the arc deteriorates, and spatter easily occurs.

The conductive core wire may have various cross-sectional shapes such as a polygonal shape and a circular shape. The arc state can be improved by using a substantially circular cross section.

In a more specific welding flux-cored wire of the present invention, the metal powder content of the flux is 50 to 60.
% By weight, the weight% of flux by weight per unit length of wire is 15.5 to 19.5% by weight, and the weight% of conductive core wire by weight per unit length of wire is It is 3.5 to 7.5% by weight. Within this range, the most desirable effect can be obtained.

[0011]

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is used for the tests shown in Table 1 below.
Showing the cross-sectional view of each flux-cored wire 1 for welding
There is. As shown in this figure, flux containing for welding for testing
The wire 1 fills the metal skin (hoop) 2 and the metal skin 2.
Filled flux 3 and metal in the approximate center of flux 3
A conductive core wire 4 arranged without being supported by the outer skin 2;
have. In Table 1, Comparative Examples 1, 6 and 7 are
No conductive core wire is placed, but except for the conductive core wire,
It has the same structure as described above. The metal skin 2 is YNiCr
_ThreeIt is made of a Ni-based alloy consisting of
Lux 3 is TiO_Two, Al_TwoO_Three, Average particle size 10
-100 μm granular metal powder made of Ni, Cr, etc.
Have The conductive core wire 4 is YNi-1 (JIS-Z
3334) formed of a Ni-based alloy
And has a circular cross-sectional shape.

Each test wire was manufactured as follows. First, as shown in FIG. 2, a strip-shaped plate material 2 ′ made of a Ni-based alloy and having a width dimension of 8 mm is rolled by a forming roll 10 so that its cross-sectional shape is U-shaped (so that an opening is formed above). After molding, the flux was filled from the flux filling device 11 and the conductive core wire 12 was inserted. Next, the closed molding roll 13 was used for further rounding. As a result, the wrap portion 2a shown in FIG. 1 is formed and the metal skin 2 is hermetically sealed in a cylindrical shape. Next, each test wire having a diameter of 1.2 mm was drawn by drawing in the drawing process. When the wire is manufactured in this manner, it is not necessary to perform a complicated process for supporting the conductive core wire on the metal outer sheath as in the conventional case, and the wire is easily manufactured. Especially the diameter dimension is 2.
When it becomes smaller than 0 mm, the manufacturing becomes easy. The outer skin thickness shown in Table 1 is the thickness of the metal outer skin of the strip-shaped plate material before the forming step, and the core wire diameter is the diameter dimension of the conductive core wire before the forming step. These dimensions are reduced by the molding process. Further, the flux amount shown in Table 1 is the weight% of the weight of the flux with respect to the weight of the unit length of the wire after the forming step, and the core dose is the conductive core with respect to the weight of the unit length of the wire after the forming step. It is the weight% of the weight of the line. The flux amount and core dose after the forming step shown in Table 1 were calculated from the respective weights of the metal shell, the flux and the conductive core wire before the roll forming and forming steps.

[0013]

[Table 1] Next, a T-type weld cracking test was performed using these test wires. This test is basically based on JIS-Z-315.
3 (1993) T-type weld cracking test. Specifically, as shown in FIG. 3, two plates P1 and P2 made of SM490A are welded in a T shape by providing a gap G of 1 mm to form a test bead B1 and a restraining bead B2. The crack length of the crater portion was obtained by the dye penetrant flaw detection test method, and the crack ratio [(crack length / crater length) × 100] was calculated. The welding conditions were a current of 200 to 210 A, a voltage of 29 to 30 V, a test bead welding speed of 300 mm / min, and a restraining bead welding speed of 250 mm / min. Further, since cracks occurred only in the crater portion, only cracks in the crater portion were examined. The test results are also shown in Table 1. From Table 1, the wires of Comparative Examples 1, 6 and 7 in which the conductive core wire is not arranged and the wire of Comparative Example 3 in which the amount of flux (% by weight of the flux with respect to the weight of the unit length of the wire) exceeds 30% by weight Then, it can be seen that the cracking rate is high. It is considered that this is because cracks were caused by impurities contained in the flux as the amount of flux increased. It can also be seen that the wires of Comparative Examples 5 and 8 in which the metal powder content of the flux is less than 20% by weight also have a high cracking rate. It is considered that this is because the electric current to the conductive core wire was insufficient and the arc became unstable. It can also be seen that the wire of Comparative Example 9 in which the metal powder content of the flux exceeds 80% by weight has a high cracking rate. This is because the required amount of non-metal flux such as arc stabilizer is reduced.

Next, the SM490A 12 × 100 ×
A bead was formed on the surface of a plate of 250 mm in a direction extending in the longitudinal direction of the plate, and the state of the arc (intensity of the arc, continuity, etc.) was visually checked in the order of good, ◯, ○, ○ ⁻ , △, ×.
The grade was evaluated. In addition, the spatter generation status was evaluated on the basis of the size and number of spatters generated, in five levels of ◎, ○, ○ ⁻ , △, ×. Specifically, the weld bead center portion 15
Sputter adhesion amount per 0 mm is 0 to 1 piece: ◎, 2 to 5
Pieces: ◯, 6 to 10 pieces: ◯ ⁻ , 11 to 25 pieces: Δ, 26 pieces or more: × was used as the evaluation standard. The test results are also shown in Table 1. From Table 1, it can be seen that the wires of Comparative Examples 1, 6 and 7 in which the conductive core wire is not arranged have a poor arc state and are likely to generate spatter. This is because in a wire having no conductive core wire, an arc is generated between the metal outer cover and the material to be welded, so that the metal outer cover is melted first and the central portion of the flux is not sufficiently melted. As a result, the arc becomes unstable and spatter easily occurs. Also, the core dose (weight% of the weight of the conductive core wire to the weight of the unit length of the wire) is 1.5% by weight.
It can be seen that the wire of Comparative Example 2 having a temperature of less than 4 is also in a poor arc state and is apt to generate spatter. This is because the core dose is small and the arc generation in the conductive core wire is not sufficient. Comparative Example 4 in which the cardiac dose exceeds 15% by weight
It can be seen that the wire also has a poor arc state and is apt to generate spatter. This is because the amount of flux is limited and the required amount of non-metallic flux such as arc stabilizer is reduced. Further, it can be seen that the wires of Comparative Examples 5 and 8 in which the metal powder content of the flux is less than 20% by weight also have a poor arc state and easily generate spatter. This is because the content of metal powder in the flux is small and the electrical conductivity between the metal outer coat and the conductive core wire is not sufficiently achieved, and the arc generation in the conductive core wire is not sufficient. Also, it can be seen that the wire of Comparative Example 9 in which the metal powder content of the flux exceeds 80% by weight has a poor arc state and is apt to generate spatter.
This is because the required amount of non-metal flux such as arc stabilizer is reduced.

Next, the relationship between the content of the metal powder in the flux and the conductivity between the metal sheath and the conductive core wire was investigated. A metal shell having a thickness of 0.5 mm and a width of 8 mm has a flux of 0.
A 1.2 mm diameter wire including a conductive core wire of 5 mm diameter was prepared, and the electric resistance value per 50 cm of each wire when the content of the metal powder in the flux was changed was examined. Table 2
Shows the result. This electric resistance value is proportional to the electric resistance value between the metal sheath and the conductive core wire.

[0016]

[Table 2] From Table 2, it can be seen that when the content of the metal powder in the flux is 20 to 80% by weight, the electric resistance value is low and the conductivity between the metal sheath and the conductive core wire can be enhanced. If it exceeds 80% by weight, the electric resistance value is low, but the required amount of non-metal flux such as an arc stabilizer is reduced, so that the state of the arc is deteriorated and spatter is easily generated.

In this example, the present invention is applied to a lap O-type welding flux-cored wire in which the wrap portion 2a is formed, but a metal outer cover as shown in FIG. The butt O type, which hits and joins without
Needless to say, the present invention can be applied to the seamless type shown in FIG. 4 (B) and the T type shown in FIG. 4 (C).

Further, in the present embodiment, the granular metal powder is used as the metal powder of the flux, but the metal powder of other shapes such as scale-like or linear may be used.

Further, in the present embodiment, the conductive core wire having a circular cross-sectional shape is used, but the conductive core wire having another cross-sectional shape such as a square shape may be used.

[0020]

According to the present invention, the flux contains a metal powder in an amount capable of lowering the electric resistance value between the metal sheath and the conductive core wire. Of electrical conductivity. As a result, even if the conductive core wire is arranged together with the flux in the metal shell without being supported by the metal shell, the conductive core wire and the material to be welded are welded together by the current flowing from the metal shell through the flux. An arc can be generated even in the interval. Therefore, unlike the conventional case, it is not necessary to perform a complicated process for supporting the conductive core wire on the metal shell, and the wire can be easily manufactured. In particular, the manufacturing becomes easy when the average outer diameter of the metal shell becomes smaller than 2.0 mm.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a test welding flux-cored wire including an embodiment of the present invention.

FIG. 2 is a diagram used for explaining a manufacturing process of the test welding flux-cored wire shown in FIG.

FIG. 3 is a diagram for explaining an aspect of a T-type weld cracking test of the test welding flux-cored wire shown in FIG. 1.

4 (A) to (C) are cross-sectional views of a flux cored wire for welding according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional welding flux cored wire.

[Explanation of symbols]

1 Flux-cored wire for welding 2 Metal skin (hoop) 3 flux 4 Conductive core

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuo Tsujikawa             7800 Nakase, Hamakita City, Shizuoka Prefecture Japan Welde             Inside the Technical Research Institute of King Rod Co., Ltd. (72) Inventor Toshio Yoshizawa             7800 Nakase, Hamakita City, Shizuoka Prefecture Japan Welde             Hingabe Works, Inc. (72) Inventor Toshiaki Fujita             7800 Nakase, Hamakita City, Shizuoka Prefecture Japan Welde             Hingabe Works, Inc. (72) Inventor Kanehisa Tanaka             7800 Nakase, Hamakita City, Shizuoka Prefecture Japan Welde             Hingabe Works, Inc. F-term (reference) 4E084 AA02 AA07 BA06 BA08 CA12                       CA24 CA25 CA27 CA38 DA09                       EA06 EA09 HA08

Claims (6)

[Claims] 1. A flux-cored wire for welding, in which a flux is filled in a pipe-shaped metal outer sheath made of Ni or a Ni-based alloy, wherein the metal outer sheath is made of Ni or a Ni-based alloy together with the flux. A conductive core wire is arranged without being supported by the metal outer cover, and the flux is added between the metal outer cover and the material to be welded, and between the conductive core wire and the material to be welded. However, a flux-cored wire for welding, characterized in that the flux-cored wire for welding contains an amount of metal powder capable of reducing an electric resistance value between the metal sheath and the conductive core wire to the extent that an arc is generated. 2. A flux-cored wire for welding in which a flux is filled in a pipe-shaped metal outer sheath made of Ni or a Ni-based alloy, wherein the metal outer sheath is made of Ni or a Ni-based alloy together with the flux. A conductive core wire is arranged without being supported by the metal skin, and 20 to 80% by weight of granular metal powder is contained in the flux, and the unit length of the wire is The weight% of the flux to the weight of the wire is 6.5 to 30% by weight, and the weight% of the weight of the conductive core wire to the weight of the unit length of the wire is 1.5 to 15% by weight. A certain flux-cored wire for welding. 3. The welding flux-cored wire according to claim 2, wherein the main component of the metal powder contained in the flux is Ni or a Ni-based alloy powder. 4. The average outer diameter of the metal skin is 2.0 m.
The flux-cored wire for welding according to claim 2 or 3, which is m or less. 5. The welding flux cored wire according to claim 4, wherein the conductive core wire has a substantially circular cross-sectional shape. 6. A flux-cored wire for welding in which a metal shell made of Ni or a Ni-based alloy is filled with flux, wherein the flux is not supported by the metal shell in the substantially central portion of the flux, and the Ni or Ni-based alloy is used. The conductive core made of is arranged in the flux, and granular metal powder is contained in the flux in an amount of 50 to 60% by weight. For welding, wherein the weight% of the weight is 15.5 to 19.5%, and the weight% of the weight of the conductive core wire to the weight of the unit length of the wire is 3.5 to 7.5% by weight. Flux-cored wire.