KR100757837B1 - Metal cored wire having superior weldability - Google Patents

Abstract

A metal-based flux cored wire which can stabilize arc transfer and can reduce the amount of slag generated on surfaces of beads by controlling flux components such as Fe and alloy elements and properly controlling contents of S and Al is provided. In a metal-based flux cored wire comprising a flux filled in a sheath of a steel material, a metal-based flux cored wire having superior weldability is characterized in that: the flux has a composition comprising, by its weight percent, 0.05 to 0.30% of C, 3.0 to 6.0% of Si, 6.0 to 12.0% of Mn, 0.02 to 0.10% of S, 0.3 to 1.5% of Al, and the balance of Fe and inevitable impurities; and a value defined as [ln(Alx100)]/S satisfies a range from 50 to 90.

Description

Metal-based flux filling wire with excellent weldability {Metal cored wire having superior weldability}

The present invention relates to a metal-based flux filling wire having iron as a flux, and more particularly, by controlling flux components such as iron and alloying elements, and controlling the content ratio of S and Al appropriately, It relates to a metal-based flux filling wire that can stabilize the transition and reduce the amount of surface slag generated.

Metal-based flux-filled wire has high welding efficiency, which is an advantage of solid wire, and good welding workability, which is an advantage of titania-based flux-filled wire, and thus is increasingly being used as a substitute for solid wire. . However, since the metal-based flux filling wire is mostly made of iron in the flux to be charged, the amount of arc stabilizer added is relatively low. As a result, the arc transfer is not smooth and spatters are generated. Due to the slag generated, there was a problem that the appearance of the beads looks somewhat messy.

Examples of techniques for solving the above problems include the inventions described in Korean Patent Nos. 347295 and 532244. The patents propose a metal-based flux filling wire that improves the weldability and the toughness of the weld by specifying the content ratio of S and Mn. However, although this technique is effective in reducing the amount of spatter and slag to some extent, the amount of slag that occurs sporadically on the surface of the weld bead has a limit that is less than the level of solid wire. Therefore, the problem of low working efficiency due to the additional slag removal work was not avoided.

Therefore, the present invention has been made to solve the problems of the prior art, and to provide a metal-based flux filling wire to stabilize the arc transition, and to obtain a healthy weld by minimizing the amount of slag generated on the surface of the beads. The purpose.

The present invention for achieving the above object,

In the metal-based flux-filled wire in which flux is filled in the steel shell, the flux is in its own weight%, C: 0.05 to 0.30%, Si: 3.0 to 6.0%, Mn: 6.0 to 12.0%, and S: 0.02 to 0.10%, Al: 0.3-1.5%, residual iron and inevitable impurities; And a metal-based flux-filled wire having excellent weldability in which a value defined by [ln (Al × 100)] / S satisfies a range of 50 to 90.

Hereinafter, the flux component composition and the content range of the metal flux filling wire of the present invention will be described.

First, carbon (C) is a component basically contained in the steel shell and flux, but does not require any addition in the present invention, but because it is a component that affects the mechanical performance of the weld metal, the content is limited within a certain range. It is preferable.

Therefore, in the present invention, the content of carbon in the flux is limited to 0.05 to 0.30% by weight (hereinafter referred to as '%'). If the content is less than 0.05%, the toughness and tensile properties of the weld metal may deteriorate. If the content exceeds 0.30%, the susceptibility to cracking increases, so the possibility of high temperature cracking increases.

Silicon (Si) is contained as a deoxidizer, in which the content is limited to 3.0 to 6.0%. This is because, if the content is less than 3.0%, deoxidation in the weld metal may be insufficient, causing surface defects. If the content is more than 6.0%, the arc stability may be lowered to increase spatter. In addition, since most of the slag components floating on the surface after welding are oxides of Si and Mn in the case of metal flux-filled wire, the amount of slag increases as the amount of Si as a deoxidizer increases.

Manganese (Mn) serves as a deoxidizer to reduce the amount of oxygen in the weld metal. In addition, manganese reacts with S as a desulfurizing agent to form MnS before FeS, thereby preventing the formation of low melting point compounds due to S segregation. In the present invention, the content of manganese is limited to 6.0 ~ 12.0%, which does not have the effect of addition when the content is less than 6.0%, if it exceeds 12.0% arc stability and meltability is lowered causing hot cracking of the weld metal Because it can be.

Sulfur (S) is one of the important additive elements in the present invention, by changing the flow of molten pool from the outside to the inside to collect the slag to the inside (center of the slag), thereby making the slag removal work easy and clean Not only can bead appearance be obtained but also serves to increase penetration.

In consideration of this, in the present invention, the amount of sulfur added is limited to 0.02 to 0.10%. If the amount is less than 0.02%, the effect of the addition can not be expected, and if it exceeds 0.10%, the arc stability is lowered, high temperature cracking is caused, and low temperature toughness may be adversely affected.

Aluminum (Al) In the present invention serves as a stronger deoxidizer than Si, Mn, and serves to reduce the amount of Si and Mn oxide slag formed as a final by-product after welding.

In the present invention, it is preferable that the amount of Al added is 0.3-1.5%. If the added amount is less than 0.3%, the slag amount reduction effect is insignificant, and if it exceeds 1.5%, the slag amount on the surface of the bead is not only increased due to the increase of Al oxide, but also Al ₂ O ₃ in the molten metal. This is because the toughness of the weld metal is reduced by forming an oxide, and the amount of fume can be increased by increasing the vapor pressure of the molten pool.

In addition, in the present invention, in order to effectively control the amount of slag generated on the surface of the bead, the value defined by the ratio of [ln (Al × 100)] / S should be controlled in the range of 50 to 90. If the ratio is less than 50 or more than 90, not only the arc transition becomes unstable, but also the amount of slag generated on the surface of the bead increases, so that a clean weld cannot be obtained.

On the other hand, the flux of the present invention as described above may be filled in the steel shell to form a metal-based flux filling wire. At this time, the present invention is not limited to the filling rate of the flux to be filled in the steel shell, it is preferable that the filling rate of the flux to be filled in the steel shell within the range of 10-20% of the total weight of the wire.

Hereinafter, the present invention will be described in detail through examples.

(Example)

Metal flux filling wires were prepared by filling the flux having the composition shown in Table 1 in the steel shell. And the steel shell used at this time, the weight percent of the shell, C: 0.02%, Si: 0.015%, Mn: 0.20%, P: 0.010%, S: 0.010%, the balance Fe and inevitable impurities have. Then, welding was performed under the welding conditions as shown in Table 2 using the flux filling wires prepared as described above.

TABLE 1

C Si Mn Al S ln (Al × 100) / S Inventive Example One 0.10 3.5 10.0 0.6 0.05 82 2 0.15 3.0 11.0 0.8 0.08 55 3 0.10 4.0 9.0 0.3 0.04 85 4 0.20 6.0 6.5 1.2 0.07 68 5 0.05 4.5 9.5 0.9 0.09 50 6 0.25 5.5 8.0 1.5 0.06 84 7 0.15 5.0 10.0 0.4 0.07 53 8 0.15 4.0 9.5 0.9 0.05 90 Comparative example One 0.25 4.0 13.0 0.2 0.01 300 2 0.25 4.0 9.5 0.5 0.04 98 3 0.20 2.5 14.0 0.6 0.05 82 4 0.15 7.0 8.0 0.8 0.06 73 5 0.20 3.0 9.0 1.2 0.12 40 6 0.20 4.5 5.5 1.4 0.04 124 7 0.15 4.5 9.5 1.7 0.13 40

TABLE 2

Welding base material Welding position Protective gas Gas flow rate Welding current / voltage / connection diagram Welding station SM490 12T 1G Ar + 20% CO ₂ 20ℓ / min 280A / 30V / 30cpm 50 cm

Subsequently, the arc stability, the spatter generation degree and the surface slag generation degree were evaluated from the welding test on the above-described flux filling wires, and the results are shown in Table 3 below. On the other hand, in this experiment, the degree of spatter generation was very good when the incidence rate was less than 3% (◎), and was good (○) when the incidence was 3-5% or less (○), normal (△), and 8 What was more than% evaluated as defective (x). The degree of slag generation was evaluated by considering both the surface area (%) occupied by the slag and the number of slag generation per 10 cm of beads. In other words, if the surface area is less than 20%, it is very good (◎), 20-30% is good (○), 30-40% is normal (△), and 40% is bad (x). When the number of occurrences is less than 2, it is very good (◎), 3 to 5 is good (○), 6 to 7 is normal (△), and the case of more than 7 is bad (x). Evaluated. Also, the arc stability was obtained through the sensory evaluation of the welder. The arc stability was evaluated by four grades of excellent (◎), excellent (○), normal (△), and poor (x). Comprehensive evaluation of good (◎), good (○), normal (△) and bad (x) was carried out.

TABLE 3

Surface slag generation Spatter level Arc stability Comprehensive Evaluation Slag occurrence per 10 cm of beads Surface area of slag Inventive Example One  ◎  ○  ◎  ◎  ◎ 2  ○  ○  ○  ○  ○ 3  ◎  ◎  ◎  ◎  ◎ 4  ◎  ◎  ○  ○  ◎ 5  ○  ○  ○  ○  ○ 6  ◎  ◎  ◎  ◎  ◎ 7  ○  ○  ◎  ◎  ◎ 8  ○  ○  ○  ◎  ○ Comparative example One  x  x  x  x  x 2  x  △  △  △  △ 3  △  ○  x  x  x 4  △  △  x  x  x 5  x  △  △  x  x 6  x  x  ○  ○  △ 7  x  x  x  x  x

As shown in Table 3, the value defined by S and Al content and [ln (Al × 100)] / S content ratio is within the scope of the present invention, the invention example of optimizing the deoxidizer (Si, Mn) content (1 ~ In case of 8), all of them showed excellent evaluation value.

On the contrary, Comparative Example (1) shows that the value defined by the [ln (Al × 100)] / S content ratio and the content of S, Al, and Mn are out of the scope of the present invention, and thus the number of slag generation and the surface area occupied by the slag. It can be seen that the increase in the arc stability is deteriorated, the comparative example (2) is that the component content of the flux is within the scope of the present invention, but the value defined by the [ln (Al × 100)] / S content ratio is outside the scope of the present invention It can be seen that the number of slag generation is large.

In addition, Baegyo (3, 4) is deoxygenating agent (Si, Mn) content is out of the scope of the present invention, the arc stability is lowered and the amount of spatter is generated, the value defined by the ratio of [ln (Al × 100)] / S content In Comparative Example (5-7) and some of the component content outside the scope of the present invention it can be seen that the number of slag generation and the surface area occupied by the slag increases and the arc stability decreases.

As described above, the present invention can stabilize the arc migration by appropriately controlling the values defined by the composition composition of the flux and the [ln (Al × 100)] / S content ratio, and by controlling the generation amount of the bead surface slag, a healthy weld can be obtained. There is a useful effect in providing a metal-based flux filling wire.

Claims (1)

In the metal-based flux-filled wire in which flux is filled in the steel shell, the flux is in its own weight%, C: 0.05 to 0.30%, Si: 3.0 to 6.0%, Mn: 6.0 to 12.0%, and S: 0.02 to 0.10%, Al: 0.3-1.5%, residual iron and inevitable impurities; And a metal-based flux filling wire having excellent weldability in which a value defined by [ln (Al × 100)] / S satisfies the range of 50 to 90.