KR100347293B1 - Metal cored wire for high speed gas shield arc fillet welding with Twin-tandem welding method - Google Patents

Abstract

A metal-based flux filled wire for two-electrode high speed fillet gas shield arc welding is provided.

The present invention, 15 to 30% metal iron by weight relative to the wire; Slag forming agent such that the value defined by (iron oxide in slag forming agent: Fe ₂ O ₃ + FeO + Fe ₃ O ₄ ) / (total of slag forming agent) is controlled to be 0.01 to 0.07; and Na ₃ AlF ₆ , K _It relates to a metal-based flux filling wire filled with a flux comprising a; ₂ SiF ₆ , CaF ₂ Alkali metal fluoride to the fluorine conversion amount of 0.05 to 0.15% at least two selected from the group consisting of.

The flux filling wire of the present invention can impart excellent slag peelability as well as excellent porosity resistance even in high-speed two-electrode tandem welding.

Description

Metal-core flux filling wire for 2-electrode high-speed fillet gas shield arc welding {Metal cored wire for high speed gas shield arc fillet welding with Twin-tandem welding method}

The present invention relates to a metal-based flux-filled wire for gas shield arc welding used for high-speed fillet welding of a primer coated steel sheet while forming one molten paper with two electrodes, and more particularly, to delay the solidification time of the molten paper. The present invention relates to a metal electrode flux-filled wire for arc welding of two-electrode high-speed fillet gas shielded arc with excellent porosity that can control the amount of diffusible hydrogen gas of the weld metal within 3 cc / 100 g.

Recently, various steel sheets are used in the heavy industry shipbuilding field, bridges and steel structures, such as twin tandem welding two sides of the fillet simultaneously while forming one molten pool with two electrodes. Welding method is used. However, since the steel sheets are usually rusted, rusted, etc. on the surface due to climate change or long time storage, when the steel sheet is welded by the twin tandem welding method in the subsequent welding process, it causes welding defects and removes them. There is a need for separate management for the loss.

Due to such condensed milk, the management of coating and storing primers on various steel sheets is carried out.However, due to various gas components generated during combustion of the primers, pit, worm holes, There is a problem that additional work maneuver occurs due to the occurrence of a blow hole (blow hole) inside.

In addition, it is required to perform a fillet of 10 m or more by high-speed welding of 1 m / min or more at a time when a method for speeding up welding has emerged in order to improve productivity in recent years. However, when the primer-coated steel sheet is welded at a high speed by a tandem welding method, first, a spatter is generated due to interference between two electrodes; Second, the appearance of the bead becomes poor due to the lack of slag foreskin; Third, under cut occurs; And there exists a problem, such as deterioration of slag peelability.

Japanese Patent Laid-Open Nos. 6-218578 and 7-314181 are examples of conventional techniques for solving the problem of deterioration in porosity caused by welding by a tandem welding method of two electrodes. The above methods suggest securing porosity above a certain level by controlling the composition ratio of the oxide to the arc stabilizer or the addition amount of TiO2 as the slag forming agent and the addition amount of the deoxidizer and the iron oxide to a predetermined value.

However, in the above methods, the primer coated steel sheet having a welded length of about 15 to 20 cm and having a normal coating thickness (40 to 50 μm) is subjected to high current (at least 400 A at the leading pole and at least 300 A at the trailing pole) at a high speed of 1 m / min or more. When welding, there are many problems in securing porosity resistance and excellent slag peelability, and there is a realistic problem in that a good bead appearance cannot be obtained.

Accordingly, the present invention is to solve the above-described problems, to provide a metal-based flux filling wire for gas shielded arc welding that can obtain not only excellent porosity but also excellent slag peelability and good bead appearance in high-speed two-electrode tandem welding. For that purpose.

The present invention for achieving the above object, 15 to 30% metal iron by weight relative to the wire; Slag forming agent such that the value defined by (sum of iron oxide in slag forming agent: Fe ₂ O ₃ + FeO + Fe ₃ O ₄ ) / (total of slag forming agent) is controlled to be 0.01 to 0.07; and Na ₃ AlF ₆ Flux-filled two-electrode high-speed fillet gas shielded arc welding metal system comprising; and an alkali metal fluoride such that the amount of fluorine in the two or more selected from the group consisting of K ₂ SiF ₆ and CaF ₂ is 0.05 to 0.15% Relates to flux filling wire.

Hereinafter, the present invention will be described.

The present invention provides a value defined as (Fe ₂ O ₃ + FeO + Fe ₃ O ₄ ) / (total of slag forming agent) in order to ensure not only excellent porosity but also excellent slag peelability even in high-speed two-electrode tandem welding. It is characterized by controlling the addition amount of the slag forming agent to fall within this predetermined range. In addition, the present invention is characterized by controlling the fluorine conversion amount of the alkali metal fluoride to be added to a certain range.

First, the flux constituting the wire of the present invention contains metal iron. Such metal iron increases the welding speed of the flux during welding and increases the productivity. In the present invention, the content of such metal iron is preferably limited to 15 to 30% by weight of the wire. If the added amount is less than 15%, the solid-solution deposition rate and welding efficiency, which are characteristic of the metal-based flux filling wire, cannot be obtained. If the content exceeds 30%, the slag forming agent is less, resulting in insufficient slag coverage and poor bead appearance. For it is done.

Meanwhile, the metal iron in the present invention includes iron alloy, but iron oxides (Fe ₂ O ₃ , FeO, and Fe ₃ O ₄ ), which are slag forming agents, described later, are not included therein.

Next, the flux constituting the wire of the present invention contains a slag forming agent. Such slag forming agents include TiO ₂ , SiO ₂ , Al ₂ O ₃ , ZrO ₂ , and the like, and various iron oxides (Fe ₂ O ₃ , FeO and Fe ₃ O ₄ ) also belong to this.

In the present invention, the amount of the slag forming agent is not limited to the amount of the added slag forming agent, and the amount of the slag forming agent is controlled so that the amount of the iron oxide relative to the total amount of the slag forming agent to be added falls within a predetermined range. That is, the inventors have found out from the research results that iron oxide, which is one of slag forming, has a lower melting point than other slag forming agents to improve slag solidification fluidity. In other words, by controlling the amount of iron oxide within a predetermined range with respect to the total amount of the slag forming agent, even when welding a primer coated steel sheet having a film thickness of 40 to 50 μm at a high current at a high speed of 1 m / min or more, excellent slag resistance It is to find that the peelability can be secured and to propose the present invention.

In detail, in the present invention, the slag forming agent is defined so that the value defined as (sum of iron oxide in the slag forming agent: Fe ₂ O ₃ + FeO + Fe ₃ O ₄ ) / (total of the slag forming agent) falls within 0.01 to 0.07. It is preferable to control the addition amount of. If the value is less than 0.01, the solidification temperature of the slag is increased, so that the time to release the primer combustion gas to the outside during the two-electrode high-speed welding is shortened, and the porosity is deteriorated. This is because the slag rushes to the lower end of the weld bead and the slag peelability and the appearance of the bead become poor. More preferably, the value is limited to 0.03 to 0.05 in order to secure excellent slag peelability and bead appearance.

In addition, in the present invention, alkali metal fluorides such as Na ₃ AlF ₆ , K ₂ SiF ₆ , and CaF ₂ are added to further improve porosity resistance. In general, fluorine (F) is known to play a role of increasing the vapor pressure of the gas components generated in the molten pool during welding, and serves to discharge harmful gas components out. In other words, in order to reduce the amount of diffusible hydrogen gas in the deposited metal to within 3 cc / 100 g, it is necessary to control the amount of fluorine (F).

In the present invention, the alkali metal fluoride such that the fluorine equivalent (sum of pure fluorine components) in at least two selected from the group consisting of Na ₃ AlF ₆ , K ₂ SiF ₆ , and CaF is 0.05 to 0.15% by weight of the wire. It is preferable to limit the addition amount of. Because, when the fluorine conversion amount is less than 0.05%, the diffusible hydrogen gas amount may be 5cc / 100g or more, and thus there is a problem in securing porosity, and when it exceeds 0.15%, the diffusible hydrogen gas amount is effectively controlled to be less than 3cc / 100g. This is because the porosity is improved but the weldability is deteriorated and a large amount of fume is generated during welding.

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

(Example 1)

After preparing the flux composition as shown in Table 1 below, using them to produce a weld wire having a wire diameter 1.6ψ. At this time, the mild steel hoop constituting the wire is composed of C: 0.02%, Si: 0.017%, Mn: 0.21%, P: 0.011%, and S: 0.013% by weight of the wire.

Next, the welding wires prepared as described above were welded to T-Fillet inorganic zinc primer steel sheets of 12mm × 100mm × 2000mm having a film thickness of 40-50 μm by twin tandem 1Pool method under the welding conditions as shown in Table 2 below. The slag peelability and bead appearance were evaluated at this time, and are shown in Table 3 below. In addition, the amount of diffusible hydrogen gas was measured by JIS Z3118 Gas Chromatography, and the porosity resistance was evaluated according to the degree of blow hole in the fracture surface inside the back surface of the welded part per 2m of the welding field.

division Flux component (% by weight) Slag formers (Total Iron Oxide) / (Total Slag Forming Agent) Fluorine conversion amount Metal iron TiO ₂ SiO ₂ Al ₂ O ₃ ZrO ₂ Iron oxide Inventive Example One 4.2 0.8 0.2 1.0 0.25 0.04 0.05 17 2 3.8 1.2 - 0.2 0.16 0.03 0.12 22 3 3.5 0.9 0.8 0.8 0.38 0.06 0.08 28 4 4.0 0.7 0.6 - 0.11 0.02 0.10 18 5 2.4 - 0.4 0.3 0.13 0.04 0.14 29 6 3.6 0.1 0.1 - 0.12 0.03 0.06 27 7 2.1 0.5 0.3 0.2 0.23 0.07 0.09 15 Comparative example One 4.2 0.8 0.2 1.0 0.25 0.04 0.05 10 2 3.8 1.2 - 0.2 0.16 0.03 0.12 34 3 3.5 0.9 0.8 0.8 0.38 0.06 0.04 28 4 4.0 0.7 0.6 - 0.11 0.02 0.2 18 5 5.2 - 0.1 0.5 0.005 0.008 0.14 29 6 4.0 0.4 - 0.4 0.65 0.12 0.06 27 7 2.4 0.6 0.4 0.2 0.23 0.06 0.17 25 8 4.5 1.3 0.4 0.9 0.79 0.10 0.04 36 9 3.8 0.3 0.6 0.4 0.02 0.004 0.01 32 10 3.0 0.8 1.1 - 0.02 0.005 0.20 13

* In the table, iron oxide means the total Fe ₂ O ₃ + FeO + Fe ₃ O ₄ content in the slag forming agent, and the fluorine equivalent is selected from the group consisting of Na ₃ AlF ₆ , K ₂ SiF ₆ , and CaF ₂ . The fluorine conversion amount (sum of pure fluorine component) in a phase is meant.

Leading and trailing plays Welding speed Welding 410A / 38V, 360A / 34V 1200mm / min 5 mm

division Test result Comprehensive Evaluation Slag peelability Bead Appearance Air resistance Diffuse hydrogen content (cc / 100g) Inventive Example One ◎ ◎ ○ 2.4 ◎ 2 ◎ ◎ ○ 2.8 ◎ 3 ○ ○ ○ 2.6 ○ 4 ○ ○ ○ 2.7 ○ 5 ◎ ◎ ◎ 3.0 ◎ 6 ◎ ◎ ◎ 2.2 ◎ 7 ○ ○ ○ 2.7 ○ Comparative example One ○ ○ △ 2.7 △ 2 △ △ ○ 2.3 × 3 ○ ○ △ 3.4 △ 4 △ △ ○ 2.5 × 5 ○ ○ △ 2.9 △ 6 △ △ ○ 2.7 × 7 △ ○ ○ 2.3 × 8 △ △ ○ 2.8 × 9 △ △ △ 4.2 × 10 △ △ △ 3.5 ×

* In the table, ◎ means good evaluation value, ○ is good, △ is normal, and × means poor.

As shown in Table 3, the invention examples (1-7) in which the amount of iron oxide in the slag forming agent is controlled to a certain range, and the fluorine equivalent is controlled to a predetermined range, all show excellent porosity resistance and slag peelability. In addition, it can be seen that the amount of diffusible hydrogen can also be controlled to less than 3cc / 100g. In particular, Examples 1, 2 and 5, 6, wherein the value defined as (sum of iron oxide: Fe ₂ O ₃ + FeO + Fe ₃ O ₄ ) / (total of slag forming agent) are in the range of 0.03 to 0.05, are not. It can be seen that better results can be obtained in terms of slag peelability and bead appearance compared to the case.

On the other hand, in the case of Comparative Examples 1 and 2, in which the addition amount of the metal iron is out of the range of the present invention, it can be seen that the slag peeling property is excessive when the addition amount is excessive, and the porosity resistance is poor when the addition amount is too small. In addition, in the case of Comparative Examples 3 and 4 in which the amount of fluorine conversion is outside the scope of the present invention as well as Comparative Examples 5 and 6 in which the amount of iron oxide in the slag forming agent is not controlled, excellent porosity resistance and slag peelability can be simultaneously satisfied. It can be seen that there is no.

In addition, in the case of the comparative examples (7-10) in which metal iron, fluorine conversion amount, etc. were out of the range of this invention, it turns out that the evaluation value is not good generally.

As described above, the present invention is for gas shielded arc welding having excellent porosity and slag peelability in high-speed two-electrode tandem welding by controlling the amount of iron oxide in the slag forming agent and defining the fluorine conversion amount in a predetermined range. The useful effect is to provide a metal based flux filling wire.

Claims (2)

In weight percent of wire, 15-30% metal iron; A slag forming agent such that a value defined as (sum of iron oxide in slag forming agent: Fe ₂ O ₃ + FeO + Fe ₃ O ₄ ) / (total of slag forming agent) is controlled to be 0.01 to 0.07; And an alkali metal fluoride such that the sum of fluorine conversion amounts in at least two selected from the group consisting of Na ₃ AlF ₆ , K ₂ SiF ₆ , and CaF ₂ is 0.05 to 0.15%. Metal Electrode Flux Filling Wire for 2-electrode High Speed Fillet Gas Shield Arc Welding The flux-filled wire according to claim 1, wherein a value defined as (sum of iron oxide in the slag forming agent: Fe ₂ O ₃ + FeO + Fe ₃ O ₄ ) / (total of the slag forming agent) is 0.03 to 0.05.