KR100550331B1 - Co2 gas shield arc welding metal cored wire - Google Patents

Abstract

A metal-based flux filling wire for carbon dioxide arc arc welding is provided.

The present invention relates to a flux-filled wire in which a flux is filled in a steel shell, wherein the flux is in its own weight%, the total amount of slag forming agent: 10-30%, TiO ₂ : 5-15%, iron (pure iron + alloy) Iron): 45 to 75%, MgO: 1.0 to 3.0%, Mn: 8.0 to 16.0%, Si: 5.0 to 10.0%, and B ₂ O ₃ : 0.01 to 0.10% It relates to a carbon-based flux filling wire for carbon dioxide arc arc welding, characterized in that the ratio of pure iron is 0.5 or less and the O ₂ content of the pure iron: 1,000 ppm or less, N ₂ content: 100 ppm or less.

The present invention is useful to provide a metal-based flux filling wire for carbon dioxide arc arc welding, which is excellent in -40 ° C. low temperature impact toughness and easy slag removal of weld metal, and excellent in high temperature crack resistance.

Metallic Flux Filled Wire, Low Temperature Toughness, Iron, O2, N2

Description

Metal flux filling wire for carbon dioxide arc welding {CO2 GAS SHIELD ARC WELDING METAL CORED WIRE}

1 is a view showing a welding specimen used in an embodiment of the present invention

The present invention relates to a metal-based flux filled wire for carbon dioxide arc arc welding suitable for fillet welding and butt pass heat input multilayer welding.

Metal-based flux filling wire is widely used in the field of manufacturing large welded structures, such as shipbuilding and steel frame, due to its excellent welding efficiency. In particular, it is mainly used for small pass high heat input welding which increases the amount of deposition per one pass and enables welding with as few passes as possible, leading to high efficiency of welding.

However, metal-based flux filling wire has high welding efficiency but low temperature impact toughness, and fillet welding of zinc-primer coated steel sheets or multi-layer welding requiring slag removal in each pass, especially narrow In the improved multilayer welding, it is difficult to remove the slag and thus there is a problem that the work efficiency is lowered. In addition, there is a high possibility of high temperature cracking in the weld metal of the first layer during the high thermal input welding.

In order to solve this problem, Japanese Patent Laid-Open Publication Nos. 6-31482 and 6-31483 have excellent slag peeling, less spatter, and prevent hot cracking and improve low temperature impact toughness. Although the present invention, the metal-based flux filling wire of the publication has a problem that it is difficult to ensure low temperature toughness in the lower temperature range of the applicable temperature range of low temperature impact toughness improvement is about room temperature or -20 ℃ degree.

Accordingly, the present invention is to solve the problems of the prior art, to provide a metal-based flux filling wire for carbon dioxide arc arc welding excellent in low-temperature impact toughness of the weld metal, easy slag removal, and excellent high temperature crack resistance It is done.

In order to achieve the above object, the present invention provides a flux-filled wire in which a flux is filled in a steel shell, wherein the flux has a total weight of slag former: 10-30%, TiO ₂ : 5-15%, Iron powder (pure iron + ferroalloy): 45 to 75%, MgO: 1.0 to 3.0%, Mn: 8.0 to 16.0%, Si: 5.0 to 10.0% and B ₂ O ₃ : 0.01 to 0.10% It relates to a metal-based flux filling wire for carbon dioxide arc arc welding, characterized in that the ratio of ferroalloy / pure iron in iron powder is 0.5 or less and the O ₂ content in the pure iron is 1,000 ppm or less, and the N ₂ content is 100 ppm or less.

Hereinafter, the present invention will be described.

The inventors have conducted research and experiments to develop a metal-based flux filling wire having excellent low-temperature impact toughness and easy slag removal of welded metals as well as high temperature crack resistance, and as a result, optimize the overall composition of the flux. In addition, the ratio of alloy iron / pure iron in the iron powder of the flux is 0.5 or less, and the pure iron has a high impact toughness even at a low temperature of -40 ℃ by controlling to O ₂ content: 1,000ppm or less, N ₂ content: 100ppm or less It is to find that the deposited metal can be obtained and to propose the present invention.

Hereinafter, the composition of the flux and the reason for its limitation, which are required to provide a metal-based flux filling wire for carbon dioxide arc arc welding, which is excellent in low-temperature impact toughness and easy slag removal as well as high temperature crack resistance, Explain.

First, the flux constituting the wire of the present invention is composed of 10 to 30% of the total amount of the slag forming agent by weight relative to the total weight of the flux. TiO ₂ , Al ₂ O ₃ , SiO ₂ , MgO, B ₂ O _3, etc., serve as a slag forming agent to protect the deposited metal from external harmful gases. If the total amount of the slag forming agent is less than 10%, the amount of slag is small so that the weld metal is not protected from external air and the weld bead is rough. If the slag forming agent exceeds 30%, the amount of iron is relatively reduced. There is a problem that the welding efficiency is lowered.

The flux in the present invention also comprises 5-15% TiO ₂ . TiO ₂ is an essential component for improving slag foreskinability and stabilizing arc.

However, if the content of the flux is less than 5%, the slag of the slag is not properly formed, the beads become uneven and the arc stability is deteriorated. Problems may arise.

The flux constituting the wire of the present invention also contains 45 to 75% of iron (pure iron + iron alloy). Iron is added in order to increase the welding efficiency. If the flux content is less than 45%, high welding efficiency, which is an advantage of the metal-based flux filling wire, cannot be obtained. If the content exceeds 75%, the deposition amount is excessive and the deposited metal tends to flow down, and the amount of the slag forming agent is relatively decreased, resulting in increased spatter and deterioration of arc stability.

Pure iron in the iron powder is different in O ₂ , N ₂ content depending on the manufacturing process.

In the present invention, the use of pure iron is controlled to less than O ₂ 1,000ppm, N ₂ 100ppm or less, when O ₂ contained more than 1,000ppm, the amount of oxide formation in the deposited metal increases, impact toughness is lowered, N ₂ is This is because if it is contained in excess of 100 ppm, nitride is formed in the deposited metal, thereby reducing the elongation and impact toughness of the deposited metal.

As described above, the pure iron in the flux can control the O ₂ , N ₂ content during the manufacturing process, iron alloy is very difficult to control these contents. In consideration of this, in the present invention, controlled by a ratio of 0.5 or less of an alloy of iron / pure iron, If the above ratio exceeds 0.5, O _2, N is the difficult ferroalloy addition amount control of the _second content increases since the O _2, in the flux N _{2, the} content increases, which adversely affects the impact toughness of the weld metal.
On the other hand, the iron alloy constituting the iron powder literally refers to a mixture consisting of iron and other metals, in the present invention, the alloy is typically made of Fe-Si, Fe-Mn, Fe-Si-Mn.

MgO is a function of controlling the solidification rate of slag as a high temperature oxide, the present invention limits the content of such MgO to 1.0 to 3.0%. Because if the flux is added less than 1.0%, the slag fluidity is so great that the weld bead becomes uneven and the slag peeling property becomes worse. to be.

Mn is a component added to increase the impact toughness of the weld metal, and the content thereof is limited to 8.0 to 16.0% in the present invention. If the content is less than 8.0%, the impact toughness improvement effect at low temperatures is insignificant, and if the content exceeds 16.0%, the toughness decreases due to excessive strength increase of the weld metal.

Si is also a component added to increase the impact toughness of the weld metal in the present invention, the content is limited to 5.0 to 10.0%, if the content is less than 5.0%, the effect of the addition is insignificant, if it exceeds 10.0% The problem that the elongation of the weld metal is lowered appears.

B ₂ O _{3 is} also added to increase the impact toughness of the weld metal, and the content thereof is limited to 0.01 to 0.10% in the present invention. This is because if the content is less than 0.01%, the toughness-improving effect due to the addition of B is insignificant, and if the content exceeds 0.10%, the probability of cracking during welding of the narrow line increases.

By filling the flux prepared as described above in the steel shell, the metal-based flux filling wire for carbon dioxide arc arc welding having excellent low temperature impact toughness and easy slag removal as well as high temperature crack resistance can be manufactured. At this time, the filling rate of the flux is preferably limited to 10 to 25% based on the total weight of the wire.

If the filling rate is less than 10%, it is impossible to expect various effects from the addition of the flux. If the filling rate exceeds 25%, there is a risk of disconnection during wire drawing, and spatter may increase.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example)

A steel shell having a composition as shown in Table 2 was filled with a flux having a composition as shown in Table 1 to prepare a plurality of metal-based flux filling wires. Then, the welding was performed on the welding specimen as shown in FIG. 1 using the flux filling wires prepared as described above, and the specific welding conditions are as follows.

Welding condition

Wire diameter: 1.6mm

Welding Current / Voltage / Speed: Super Layer-280A / 32V / 20 ~ 25cpm

                       2 ~ final layer-450A / 36V / 20 ~ 25cpm

Protective gas: 100% CO2 (25 ℓ / min)

Interlayer Temperature: 150 ℃ ± 15

Base material thickness 20mm: 3 layers / 5 pass

Base material thickness 30mm: 4 layers / 7 pass

Welding heat input: 40 ~ 45 KJ / cm

After welding as described above, high temperature crack resistance, slag peeling, impact toughness (measurement of Charpy absorbed energy at -40 ° C) of the weld metal was measured, and the results are shown in Table 3. Among them, the high temperature crack resistance was first layer welded on the specimen as shown in Fig. 1, and evaluated as good (O) or poor (×) depending on the presence of cracks on the surface of the weld bead. O, normal was evaluated as Δ, and defect was evaluated as ×, and the results were shown.

division No. Mn Si B ₂ O ₃ iron content                                              Type of pure iron * Ferroalloy / Pure Iron MgO Slag forming agent TiO ₂ Foot honor One 8.5 7.0 0.06 71 A 0.40 1.5 14 6 2 12.0 5.5 0.04 66 A 0.22 2.0 17 7 3 13.5 8.9 0.08 55 A 0.31 2.3 23 13 4 15.5 9.4 0.02 48 A 0.23 2.8 28 14   Comparative Example 5 5.5 7.4 0.03 66 A 0.42 1.7 22 6 6 18.5 6.7 0.04 60 A 0.37 1.6 15 6 7 9.3 8.3 0.005 64 A 0.44 2.3 19 8 8 9.0 8.9 0.18 62 A 0.31 2.5 21 7 9 10.5 6.6 0.05 59 A 0.67 2.4 24 8 10 15.4 5.2 0.05 58 A 0.71 1.9 39 11 11 15.3 7.3 0.07 40 A 0.28 0.5 28 12 12 9.4 3.3 0.04 67 A 0.22 1.3 21 12 13 12.0 5.5 0.04 66 B 0.20 2.0 17 7 14 9.5 6.2 0.08 78 B 0.30 2.3 8 4 15 12.7 7.8 0.05 58 A 0.46 2.7 22 18 16 13.5 6.9 0.09 71 A 0.15 1.4 9 5 17 14.8 5.7 0.05 45 A 0.19 2.7 35 10

* In Table 1, A represents the case of O ₂ 1,000 ppm or less in pure iron, N ₂ 100 ppm or less, and B represents the case of O ₂ exceeding 1,000 ppm and N ₂ 100 ppm.

Outer chemical composition (% by weight) C Si Mn P S 0.02 0.02 0.20 0.010 0.012

division No. High temperature crack resistance Slag peelability Impact Toughness (vE _{-40 ℃} . J) Base material thickness 20mm Base material thickness 30mm Foot honor One O O 72 70 2 O O 69 71 3 O O 72 68 4 O O 69 72    Comparative Example 5 O O 41 44 6 O O 35 39 7 O O 45 42 8 × O 38 40 9 O O 37 36 10 O O 38 37 11 O O 50 51 12 O × 46 44 13 O △ 33 35 14 O × 29 30 15 O △ 51 56 16 O × 54 53 17 O △ 55 57

As shown in Table 1 and Table 3, Inventive Example (1-4), the composition of the metal-based flux filling wire is within the scope of the present invention is not only good high temperature crack resistance and slag peelability, but also low temperature impact toughness Excellent.

On the contrary, the comparative example (5-17) in which the flux composition was out of the scope of the present invention was not satisfactory in terms of impact toughness at low temperatures.

That is, in Comparative Examples (5, 6, 7, and 12), Mn, Si, or B ₂ O ₃ amount was out of the present invention, and the impact toughness was low. In Comparative Example (8), B ₂ O ₃ was excessively high. The addition caused hot cracking.

In addition, the comparative examples (9, 10) showed a low impact toughness as the ratio of ferroalloy / pure iron is outside the scope of the present invention, Comparative Example (11) did not show a high welding efficiency because the amount of iron is small.

And Comparative Example (15, 16, 17) showed a somewhat high value of low-temperature impact toughness, but as one component of the TiO ₂ , slag forming agent is out of the scope of the present invention, the slag peelability is poor and the beads are rough Indicated. In particular, Comparative Examples (13, 14) added with pure iron having high O ₂ and N ₂ contents showed the lowest impact toughness among the Comparative Examples.

As described above, the present invention has the effect of improving the low-temperature impact toughness of the weld metal by appropriately adjusting the flux composition of the metal-based flux-filled wire and using pure iron having a controlled content of O ₂ and N ₂ as the iron powder of the flux. Can be obtained.

Claims (2)

In the flux filling wire in which the flux is filled in the steel shell, The flux is in terms of its own weight percent, total slag forming agent: 10-30%, TiO ₂ : 5-15%, iron (pure iron + ferroalloy consisting of Fe-Si, Fe-Mn and Fe-Si-Mn): 45 to 75%, MgO: 1.0 to 3.0%, Mn: 8.0 to 16.0%, Si: 5.0 to 10.0%, and B ₂ O ₃ : 0.01 to 0.10%. Less than 0.5 and the pure iron O ₂ content: 1,000ppm or less, N ₂ content: 100ppm or less characterized in that the metal-based flux filling wire for arc welding. The metal-based flux filling wire for carbon dioxide arc welding according to claim 1, wherein the flux is filled in the steel shell at a filling rate of 10 to 25%.

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