JP2015073997A - Two-electrode horizontal fillet gas shielded arc welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-electrode horizontal fillet gas shielded arc welding method which stabilizes an arc state and a basin state, causes little sputter, keeps a bead shape, slag coverage, and slag peelability excellent, and enables weld beads of uniform leg lengths with no generation of pits.SOLUTION: A two-electrode horizontal fillet gas shielded arc welding method is characterized in that welding is carried out by using a welding solid wire for a preceding electrode, and a welding flux-cored wire for a succeeding electrode with an interelectrode distance between the preceding electrode and the succeeding electrode by 10-40 mm, with a torch angle of the preceding electrode and the succeeding electrode at 40-60° to a lower plate, with a sweep-back angle of the preceding electrode at 1-25° to a direction of welding progress, with a sweep-forward angle of the succeeding electrode at 1-25° to a direction of welding progress, with the wire diameter of the preceding electrode and that of the succeeding electrode by 1.2-2.0 mm, and by setting the wire diameter of the preceding electrode to less than the wire diameter of the succeeding electrode with a total of the preceding electrode current and the succeeding electrode current at 400-1000A.

Description

The present invention relates to a two-electrode horizontal fillet gas shielded arc welding method for horizontal fillet welding of various steel plates including mild steel and 490 N / mm ² grade high-strength steel plates, and in particular, primer coated steel plates such as inorganic zinc. The present invention relates to a two-electrode horizontal fillet gas shielded arc welding method suitable for improving the bead shape and the pore resistance, which are problems in long horizontal fillet welding.

  Gas shield arc welding is widely used in the field of ships and bridges in recent years. For the purpose of further improving the efficiency of welding, for example, horizontal corners in a two-electrode one-pool system as shown in Patent Documents 1 and 2 are used. Meat gas shielded arc welding has been proposed and used for long long welding. By using the horizontal fillet gas shielded arc welding of this two-electrode one-pool system, the amount of welding can be secured without lowering the welding speed, so that highly efficient welding is possible.

  FIG. 1 is a schematic diagram showing the situation of horizontal fillet gas shielded arc welding in a two-electrode / one pool system, and FIG. 2 shows an example of a bead-shaped defect in horizontal fillet gas shielded arc welding in a two-electrode / one pool system. As shown in FIG. 1, in order to obtain a good bead shape by two-electrode horizontal fillet gas shielded arc welding, an angle θ1 (hereinafter referred to as a receding angle) of the leading electrode wire 1 in a rearward oblique direction with respect to the vertical direction. It is important that the trailing electrode wire 2 has an angle θ2 (hereinafter referred to as a forward angle) in a diagonally forward direction with respect to the vertical direction, and a stable puddle 3 is formed between the two electrodes. .

  However, in horizontal fillet gas shielded arc welding in the two-electrode one-pool method, when the welding current is in a high current region (for example, a welding current of 450 A or more for both electrodes), the state of the puddle 3 formed between the two electrodes and The arc state becomes unstable due to the interference of the strong arc force of the two electrodes, the bead shape of the weld bead is disturbed, and the leg length is also uneven.

  For example, when a sound welding bead is to be obtained by welding at a welding speed of 1.0 m / min or higher, the welding current is increased to secure a large amount of welding, so welding is performed in a high current region, and the leading electrode wire Since both the arc force of 1 and the trailing electrode wire 2 become strong, the puddle 3 also becomes unstable due to the arc force. Furthermore, since the arc state becomes unstable, the fluctuation of the hot water puddle 3 itself becomes very large in the end, and there is a problem that a good weld bead 7 cannot be formed. In addition, since the molten slag 5 formed on the surface of the molten pool 4 behind the trailing electrode is not stable, the encapsulated state of the solidified slag 6 formed by solidification becomes non-uniform. As a result, as shown in FIG. 2, defects such as undercut 11 and overlub 12 occur in the welded portion, the slag peelability becomes poor, and the leg length of the weld bead becomes uneven.

  In recent years, for the purpose of rust resistance, a steel plate (hereinafter referred to as a primer-coated steel plate) in which an inorganic zinc primer 8 is coated on the steel plate surface is often used. When such a primer-coated steel plate is welded, as shown in FIG. 2, the primer 8 coated on the upright plate 9 and the lower plate 10 and red rust on the surface of the steel plate and the adhering moisture are vaporized during welding to generate steam gas. . For this reason, the pits 13 are generated, and it takes time for the rework welding, so that there is a problem that the production cost is increased.

  As a method for solving these problems, a technique disclosed in Patent Document 3 has been proposed. In this Patent Document 3, in the case of using a primer coated steel sheet by limiting the content of the flux-cored wire used for the leading electrode and the trailing electrode in the horizontal fillet gas shielded arc welding in the two-electrode one-pool method A method is disclosed for improving the porosity resistance. However, in the flux-cored wire disclosed in Patent Document 3, when the welding speed is 1.0 m / min or more, the molten slag 5 that encapsulates the surface of the molten pool 4 is insufficient, so that the solidified slag 6 becomes the weld bead 7. Cannot be encapsulated uniformly, and the generation of pits cannot be sufficiently suppressed.

JP 63-235077 A JP-A-2-280968 JP 2009-190042 A

  Therefore, the present invention has been devised in view of the above-described problems. In two-electrode horizontal fillet gas shielded arc welding of a primer coated steel plate such as inorganic zinc, the arc state is good, the spatter is small, A stable weld bead with stable accumulation and no undercut or overlap is obtained, slag encapsulation and slag peelability are good, pits are few, and a weld bead with uniform leg length can be obtained. An object is to provide an electrode horizontal fillet gas shielded arc welding method.

  In order to solve the above-mentioned problems, a two-electrode horizontal fillet gas shielded arc welding method according to the present invention is a two-electrode horizontal fillet gas shielded arc welding method, in which a welding solid wire is welded to a leading electrode and a trailing electrode is welded. Using a flux-cored wire, the distance between the leading electrode and the trailing electrode is 10 to 40 mm, the torch angle with respect to the lower plate of the leading electrode and the trailing electrode is 40 to 60 °, and the receding angle of the leading electrode with respect to the welding progress direction 1 to 25 °, the advance angle of the trailing electrode with respect to the welding direction is 1 to 25 °, the wire diameter of the leading electrode and the trailing electrode is 1.2 to 2.0 mm, and the wire diameter of the leading electrode is The wire diameter is equal to or smaller than the wire diameter of the row electrode, and the total of the leading electrode current and the trailing electrode current is welded at 400 to 1000 A.

  Moreover, in the two-electrode horizontal fillet gas shielded arc welding method according to the present invention, the welding flux-cored wire is in mass% with respect to the total mass of the wire, and the total amount of the slag forming agent in the flux is 3.5 to 8.5. And the balance is iron powder, alloy powder and inevitable impurities.

  According to the two-electrode horizontal fillet gas shielded arc welding method of the present invention, when a primer-coated steel plate such as inorganic zinc is welded by two-electrode horizontal fillet gas shielded arc welding, the arc state is good and spatter is small. It is possible to obtain a weld bead with a stable puddle, a sound weld bead with no undercut or overlap, good slag encapsulation and slag peelability, few pits, and uniform leg length. Therefore, it is possible to improve the efficiency of welding and improve the quality of the welded portion.

It is a schematic diagram which shows the condition of the horizontal fillet gas shield arc welding of a 2 electrode 1 pool system. It is a schematic diagram which shows the example of a defect of the bead shape in 2 electrode horizontal fillet gas shield arc welding.

In order to solve the above-mentioned problems in welding various steel plates including mild steel and 490 N / mm ² grade high-strength steel plate, the present inventors have used a two-electrode, one-pool system using a primer-coated steel plate such as inorganic zinc. We investigated various welding conditions for horizontal fillet gas shielded arc welding. As a result, by using a welding solid wire for the leading electrode wire and a welding flux-cored wire for the trailing electrode wire, the molten slag generated from the welding flux-cored wire of the trailing electrode wire is uniformly covered on the surface of the welding bead. It was found that slag encapsulation, slag peelability and bead shape can be improved.

  In addition, since the arc force generated from the solid wire for welding the leading electrode wire is strong, a vigorous stirring action occurs in the hot water pool formed between the leading electrode wire and the trailing electrode wire, and the vapor gas generated from the primer is reduced. It has also been found that the generation of pits can be suppressed by releasing a large amount outside the puddle.

  In addition, the solid wire for welding has less oxygen in the wire than the flux-cored wire for welding, so when the solid wire for welding is used for the lead electrode wire, the flux-cored wire for welding is used for both electrodes Compared to the above, the amount of oxygen in the puddle is reduced, and the surface tension of the molten pool formed behind the trailing electrode wire is increased, so that the sag of the weld bead is reduced and the end of the weld bead on the vertical plate side (hereinafter, It was found that a weld bead having a uniform bead upper end) and a weld bead end on the lower plate side (hereinafter referred to as a bead lower end) can be obtained.

  Further, the inter-electrode distance d between the leading electrode wire and the trailing electrode wire (interval of arc generation points), the torch angle θ3 (hereinafter referred to as the torch angle) with respect to the lower plate of the leading electrode and the trailing electrode, and each electrode wire. The receding angle θ1 and the advancing angle θ2 with respect to the welding progress direction of the lead electrode wire are defined, and the wire diameter of the leading electrode wire is made equal to or smaller than the wire diameter of the trailing electrode wire, and the welding current of the leading electrode wire and the welding current of the trailing electrode wire are By defining the total, it was found that the arc state and the puddle state during welding were stabilized to reduce spatter, a sound weld bead with no undercut or overlap was obtained, and slag peelability could be improved. .

  The reasons for limiting the welding conditions of the two-electrode horizontal fillet gas shielded arc welding method in the present invention will be described below.

[Use welding solid wire for leading electrode and welding flux-cored wire for trailing electrode]
The solid wire for welding has a smaller amount of oxygen in the wire than the flux-cored wire for welding. If a solid wire for welding is used for the leading electrode in horizontal fillet gas shielded arc welding with a two-electrode, one-pool system using a primer-coated steel plate such as inorganic zinc, a flux-cored wire for welding is used for both the leading and trailing electrodes. The amount of oxygen in the puddle is lower than that of the hot water pool and the surface tension of the molten pool formed behind the trailing electrode wire is increased, so that the weld bead sag is reduced and a weld bead with a uniform leg length is obtained. Can do. Moreover, since the arc force from the welding solid wire of the leading electrode is strong, the hot water pool formed between the two electrodes is vigorously stirred, and the vapor gas generated from the primer coated steel plate such as inorganic zinc is released outside the hot water pool. Therefore, pits can be reduced.

  When a flux-cored wire for welding is used for both the leading electrode and the trailing electrode, the amount of oxygen in the puddle increases, so that the weld bead tends to sag and the leg length of the weld bead becomes uneven. In addition, since the arc of the leading electrode is weaker than when the solid wire for welding is used, the hot water pool between the two electrodes is not sufficiently stirred, and the generation of pits cannot be sufficiently suppressed.

  When a solid wire for welding is used for both the preceding electrode and the succeeding electrode, the arc state becomes unstable due to the mutual interference between the arc of the preceding electrode and the arc of the succeeding electrode, resulting in frequent spattering. Further, since the arc of the trailing electrode is strong, the weld bead becomes convex and the bead shape becomes poor. Further, since the slag forming agent supplied from both electrodes is extremely small, the molten slag cannot encapsulate the entire molten pool, cannot support the drooping of the weld bead, the weld bead leg length becomes uneven, and the slag cover Packaging and slag peelability are also poor.

  When a flux-cored wire for welding is used as the leading electrode and a solid wire for welding is used as the trailing electrode, the welding electrode is used to adjust the bead shape. Strong, the weld bead becomes convex, and the bead shape becomes poor. Moreover, since molten slag cannot be uniformly encapsulated on the entire surface of the molten pool, the leg length of the weld bead becomes uneven, and the slag encapsulation and slag peelability are poor.

  Therefore, a welding solid wire is used for the leading electrode, and a welding flux-cored wire is used for the trailing electrode.

[Distance between leading electrode and trailing electrode: 10 to 40 mm]
In order to form a stable puddle by horizontal fillet gas shielded arc welding in the 2-electrode 1-pool method, it is necessary to make the distance between the leading electrode and the trailing electrode (interval of arc generation point) appropriate. . If the distance between the leading electrode and the trailing electrode is less than 10 mm, a stable puddle is not formed between the two electrodes, and the bead shape becomes poor. Further, the arc state becomes unstable due to the mutual interference between the arc of the preceding electrode and the arc of the succeeding electrode, and sputtering occurs frequently. On the other hand, if the distance between the leading electrode and the trailing electrode exceeds 40 mm, a pool of 1 pool is not formed, and an arc of the trailing electrode is generated on the solidified metal after melting at the leading electrode. As a result, the arc state becomes unstable, spattering occurs frequently, and the bead shape becomes poor. Therefore, the distance between the leading electrode and the trailing electrode is 10 to 40 mm.

[Torch angle with respect to lower plate of leading electrode and trailing electrode: 40-60 °]
In horizontal fillet gas shielded arc welding using the 2-electrode 1-pool method, if the torch angle with respect to the lower plate of the leading electrode and the trailing electrode is less than 40 °, the arc is too close to the lower plate side and the arc state is unstable. And spatter frequently occurs. Furthermore, an undercut occurs at the lower end of the bead and the bead shape becomes poor, and the leg length on the lower plate side becomes small, resulting in a weld bead with an uneven leg length. On the other hand, when the torch angle with respect to the lower plate of the leading electrode and the trailing electrode exceeds 60 °, the arc is too close to the standing plate side, the arc state becomes unstable, and sputtering occurs frequently. Furthermore, an overlap occurs at the lower end of the bead and an undercut occurs at the upper end of the bead, resulting in a poor bead shape, and the leg length on the standing plate side is also reduced, resulting in a weld bead with an uneven leg length. Therefore, the torch angle with respect to the lower plate of the leading electrode and the trailing electrode is 40 to 60 °.

[The receding angle of the leading electrode with respect to the welding direction: 1 to 25 °, the advancing angle of the trailing electrode with respect to the welding direction: 1 to 25 °]
In horizontal fillet gas shielded arc welding by the two-electrode one-pool method, it is very important to form a stable puddle between the leading electrode and the trailing electrode. That is, the leading electrode has a receding angle with respect to the welding progress direction, and the trailing electrode has an advancing angle with respect to the welding progress direction, thereby forming a stable puddle between the two electrodes and forming behind the trailing electrode. The molten slag is uniformly encapsulated on the surface of the molten pool, and a weld bead having good slag encapsulation and bead shape can be obtained. If the receding angle of the leading electrode and the advancing angle of the following electrode are less than 1 °, the above-mentioned effect cannot be obtained, and the molten pool surface cannot be uniformly encapsulated with molten slag. It becomes defective. On the other hand, when the receding angle of the leading electrode exceeds 25 °, the arc of the leading electrode pushes up the puddle, the fluctuation of the puddle and the molten pool becomes large, the puddle state and the arc state become unstable, and the spattering occurs. Occurs frequently, and the slag encapsulation and bead shape also become poor. Further, when the advance angle of the trailing electrode exceeds 25 °, the fluctuation of the height of the molten pool formed behind the trailing electrode becomes large, and the slag encapsulation property and the bead shape become poor. In addition, the arc state becomes unstable and spatter occurs frequently. Therefore, the receding angle of the preceding electrode with respect to the welding direction is 1 to 25 ° with respect to the vertical direction, and the advancing angle of the succeeding electrode with respect to the welding direction is 1 to 25 ° with respect to the vertical direction.

[Wire diameters of the leading electrode and the trailing electrode: 1.2 to 2.0 mm, and the wire diameter of the leading electrode is equal to or smaller than the wire diameter of the trailing electrode]
In general welded structures such as ships and bridges, the leg length of the weld bead is required to be more than 4 mm, and it is necessary to select a wire diameter suitable for the leg length and welding speed for the wire diameter of the leading electrode and the trailing electrode. is there. If the wire diameters of the leading electrode and the trailing electrode are less than 1.2 mm, the wire feed speed must be increased to near the upper limit in order to ensure the target leg length (4 mm or more), and the arc state is not good. It becomes stable, spatter frequently occurs, and the bead shape becomes poor. On the other hand, if the wire diameter of the leading electrode and the trailing electrode exceeds 2.0 mm, the wire cannot be fed with a normal wire feeding device, and a dedicated wire feeding device must be installed, so the equipment cost is low. Get higher. Furthermore, when the wire diameter of the leading electrode exceeds the wire diameter of the trailing electrode, the arc spread becomes small and the hot water pool is not stable, so that the bead shape becomes poor. Therefore, the wire diameter of the preceding electrode and the succeeding electrode is 1.2 to 2.0 mm, and the wire diameter of the preceding electrode is not more than the wire diameter of the succeeding electrode.

[Total of leading electrode current and trailing electrode current: 400 to 1000 A]
The sum of the leading electrode current and the trailing electrode current corresponds to the wire feed amount of both electrodes, and is important for securing a necessary welding amount and forming a good weld bead. If the total of the leading electrode current and the trailing electrode current is less than 400 A, a sufficient amount of welding for forming a weld bead cannot be secured, and the bead shape becomes poor. On the other hand, if the sum of the leading electrode current and the trailing electrode current exceeds 1000 A, the arc of the leading electrode and the trailing electrode becomes very strong, and the fluctuation of the puddle formed between the two electrodes becomes large. In addition, the state of the hot water pool becomes unstable, spatter is frequently generated, and the bead shape is also poor. Therefore, the total of the leading electrode current and the trailing electrode current is 400 to 1000A.

[Total slag forming agent: 3.5 to 8.5%]
By performing horizontal fillet gas shielded arc welding using the 2-electrode 1-pool method under the welding conditions described above, the arc and puddle conditions are stable, spatter and pits are less likely to occur, slag encapsulation, and slag peeling. Therefore, it is possible to obtain a weld bead having a uniform leg length without undercuts or overlaps, thereby achieving high welding efficiency. On the other hand, in the case of welding with a primer-coated steel plate such as inorganic zinc, in order to further improve the slag encapsulation and slag peelability and bead shape, the amount of slag forming agent of the flux-cored wire for welding used for the trailing electrode should Must be limited.

The slag forming agent for welding flux-cored wire becomes a molten slag when a weld bead is formed by horizontal fillet gas shielded arc welding in the two-electrode one-pool system, and encapsulates the entire surface of the weld bead. While adjusting the bead shape, the molten metal is prevented from flowing to the lower plate side, and the leg length of the weld bead is made uniform. If the total amount of slag forming agent is less than 3.5% by mass with respect to the total mass of the wire, the slag generation amount is insufficient and the entire weld bead cannot be encapsulated uniformly, resulting in poor bead shape and melting. The slag is seized on the weld bead, and the slag peelability is also poor. On the other hand, if the total amount of the slag forming agent exceeds 8.5% by mass with respect to the total mass of the wire, the slag is excessively generated and unevenness occurs in the slag encapsulating state, resulting in a poor bead shape. Therefore, the sum total of the slag formation agent contained in the flux in the flux-cored wire for welding is 3.5 to 8.5% by mass with respect to the total mass of the wire. The slag forming agent includes TiO ₂ , SiO ₂ , ZrO ₂ , Na ₂ O, K ₂ O, Al ₂ O ₃ , FeO, Fe ₂ O ₃ , MgO and other oxides and CaF ₂ , K ₂ SiF ₆ , This refers to the total of fluorides such as Na ₃ AlF ₆ .

  The reasons for limiting the constituent components of the flux-cored wire for welding used for the trailing electrode of the present invention have been described above, the balance being steel outer shell components C, Si, Mn, Fe, iron powder in the flux, alloy powder And inevitable impurities. An appropriate amount of iron powder can be added for the purpose of increasing the welding speed. Further, the alloy powder refers to metal powder such as Si, Mn, Ti, Al, Mg, and iron alloy powder such as Fe-Si, Fe-Mn, Fe-Si-Mn, Fe-Al, Fe-Ti, and the like. An appropriate amount can be added for the purpose of improving the mechanical properties of the weld metal.

  The steel outer shell is a hot-rolled steel strip having excellent wire drawing workability after flux filling, and is C: 0.10% or less, Si: 0.05% or less, Mn: 0.20 to 0.80%, P: 0.050% or less, S: 0.050% or less are suitable, and in particular, C is 0.005 to 0.03. % Is also effective for reducing spatter and reducing fume.

  The cross-sectional shape of the flux-cored wire for welding may be either a caulking type or a seamless type, but the seamless type that can be plated with copper on the wire surface has less wear on the tip and a long stable arc state. The time can be maintained, and the efficiency of welding can be improved. Moreover, since there is no seam in a wire, it is excellent in hygroscopicity and can be stored for a long time.

  Furthermore, the hydrogen content and the nitrogen content in the flux-cored wire for welding are desirably 40 ppm or less with respect to the total mass of the wire in order to prevent deterioration of the pore resistance and impact toughness.

  In addition, it is effective to intentionally add S as a slag remover in the form of FeS or the like, but if S exceeds 0.030% by mass with respect to the total mass of the wire, the slag encapsulation is poor. Thus, the bead shape becomes defective.

The shielding gas used in the two-electrode horizontal fillet gas shielded arc welding method of the present invention is CO ₂ gas.

    Hereinafter, the present invention will be described more specifically with reference to examples.

  Hot rolled steel strip with mild steel skin (C: 0.02 mass%, Si: 0.01 mass%, Mn: 0.35 mass%, Al: 0.02 mass%, N: 0.0015 mass%) The various fluxes comprising the slag forming agent content shown in Table 1 are filled at a flux filling rate of 17% by mass, the end surfaces of the steel outer shell are welded together to make a seamless shape, and then welded to various wire diameters. Various types of flux-cored wires were manufactured.

The welding flux-cored wire shown in Table 1 is used as a trailing electrode, the leading electrode is used as a solid wire for welding consisting of the contents of each component shown in Table 2, and various welding conditions shown in Table 3 are used. Horizontal fillet gas shielded arc welding (one-pass simultaneous welding on both sides) was performed using an electrode 1 pool system, and the welding workability was investigated. The shield gas was CO ₂ gas, and welding was performed at a gas flow rate of 25 liters / min and a weld length of 750 mm.

Specimen is a steel plate with 490 N / mm grade ² high-strength steel coated with inorganic zinc primer (primer film thickness is about 15 μm on the side, milled on the end face, steel plate dimensions: plate width 100 mm × length 1000 mm × plate thickness 12 mm) The one assembled in a T-shape with no gap between the lower plate and the standing plate was used.

  T-shaped test specimens by horizontal fillet gas shielded arc welding using a two-electrode, one-pool system, arc stability of each prototype wire, spatter generation, stability of a sump between two electrodes, slag encapsulation The slag peelability, the number of pits generated, the bead shape, and the leg length (actually measured values) were investigated and evaluated. It was confirmed by visual observation whether the arc stability, the stability of the hot water pool between the two electrodes, slag encapsulation, slag peelability, and bead shape were good. Further, whether the amount of spatter generated was large by visual observation, and the number of pits generated was first checked for the presence or absence of pits, and the number of pits generated was measured. Further, the leg length (measured value) was determined by observation with the aim of whether the leg length was good or uneven. The results are summarized in Table 4.

  In Table 3 and Table 4, No. W1 to W9 are examples of the present invention, no. W10 to W25 are comparative examples.

  No. which is an example of the present invention. W1-W7 uses a solid wire for welding for the leading electrode, a flux-cored wire for welding for the trailing electrode, the distance between the leading electrode and the trailing electrode, the torch angle with respect to the lower plate of the leading electrode and the trailing electrode, welding The advance angle of the preceding electrode with respect to the advancing method, the advance angle of the succeeding electrode with respect to the welding advancing method, the wire diameters of the preceding electrode and the succeeding electrode are appropriate, and the wire diameter of the preceding electrode is less than or equal to the wire diameter of the succeeding electrode. Since the sum of the electrode current and the subsequent electrode current is also within the range specified in the present invention, and the content of the slag forming agent in the welding flux-cored wire rack is also within the range specified in the present invention, 2 Arc fill stability of horizontal fillet gas shielded arc welding with electrode 1 pool system, hot water stability between two electrodes, bead shape, slag encapsulation and slag peelability are all good, Sputtering generation amount is small, no generation of pits, it is possible to obtain a weld bead uniform leg length, was very good results.

  In addition, No. In W8, the slag forming agent of the flux-cored wire for welding (symbol d) used for the trailing electrode was less than 3.5% by mass, so the slag encapsulation property, slag peelability, and bead shape were slightly poor. There was no problem with the quality of the weld. No. In W9, the amount of slag forming agent for welding flux-cored wire (symbol e) used for the succeeding electrode is more than 8.5% by mass, so the slag encapsulating property and bead shape were somewhat poor. There was no problem.

  No. in the comparative examples. W10 used welding flux-cored wire (symbol b) for both the leading electrode and the trailing electrode, so the porosity was poor, pits were generated, and the leg length was also uneven. Further, since the distance between the leading electrode and the trailing electrode is less than 10 mm and short, the arc state and the hot water pool state become unstable, spatter frequently occurs, and the bead shape is also poor.

  No. In W11, since the welding solid wire (symbol f) was used for both the leading electrode and the trailing electrode, the arc state became unstable and spatter occurred frequently. Furthermore, the slag encapsulation and slag peelability and the bead shape were poor, and the leg length was also uneven.

  No. W12 used welding flux-cored wire for the leading electrode and solid wire for welding (symbol f) for the trailing electrode, so the slag encapsulation and slag peelability and bead shape were poor, and the leg length was also uneven. It was.

  No. In W13, since the distance between the leading electrode and the trailing electrode is longer than 40 mm, the arc state and the hot water pool state become unstable, spatter frequently occurs, and the bead shape is also poor. Furthermore, since the wire diameter of the trailing electrode is 2.4 mm, a dedicated welding power source and a wire feeding device are required.

  No. In W14, since the torch angle with respect to the lower plate of the leading electrode and the trailing electrode is less than 40 ° and is small, the arc state becomes unstable and spattering frequently occurs. Furthermore, undercuts occurred, the bead shape was poor, and the leg length was uneven.

  No. Since W15 has a large torch angle with respect to the lower plate of the leading electrode and the trailing electrode exceeding 60 °, the arc state becomes unstable and spattering frequently occurs. Furthermore, an overlap occurred, the bead shape was poor, and the leg length was uneven.

  No. In W16, the receding angle of the leading electrode with respect to the welding progress direction was less than 1 ° and was small, so that the slag encapsulation and bead shape were poor.

  No. In W17, the receding angle of the leading electrode with respect to the welding progress direction was larger than 25 ° and was large, so that the arc state and the hot water pool state became unstable and spatter occurred frequently. Furthermore, slag encapsulation and bead shape were poor.

  No. In W18, since the advance angle of the succeeding electrode with respect to the welding progress direction was less than 1 ° and was small, the slag encapsulation was poor and the bead shape was poor.

  No. In W19, the advance angle of the succeeding electrode with respect to the welding progress direction is greater than 25 ° and is large, so that the arc state becomes unstable and spatter frequently occurs. Furthermore, slag encapsulation and bead shape were poor.

  No. In W20, since the wire diameters of the leading electrode and the trailing electrode are both smaller than 1.2 mm and are small, the arc state becomes unstable, spatter frequently occurs, and the bead shape is also poor.

  No. In W21, since the wire diameter of the preceding electrode exceeds the wire diameter of the succeeding electrode, the hot water pool state becomes unstable and the bead shape is also poor.

  No. In W22, since the total of the leading electrode current and the trailing electrode current was less than 400 A, the welding amount was insufficient and the bead shape was poor.

  No. In W23, the sum of the leading electrode current and the trailing electrode current was higher than 1000 A, so that the arc state and the hot water pool state became unstable, spatter occurred frequently, and the bead shape was poor.

  No. For W24, the wire diameter of the leading electrode was 2.4 mm, and a dedicated welding power source and a wire feeding device were required. Furthermore, since there are few slag formation agents of the flux cored wire for welding (code | symbol d), slag encapsulation property, slag peelability, and bead shape were inferior.

  No. W25 used welding flux-cored wires for both the leading electrode and the trailing electrode, so the porosity was poor, pits were generated, and the leg length was uneven. Furthermore, since there are many slag formation agents of the flux-cored wire for welding (symbol e), the slag encapsulation and bead shape were poor.

DESCRIPTION OF SYMBOLS 1 Lead electrode wire 2 Subsequent electrode wire 3 Hot water pool 4 Molten pool 5 Molten slag 6 Solidified slag 7 Weld bead 8 Primer 9 Standing plate 10 Lower plate 11 Undercut 12 Overlap 13 Pit

Claims (2)

In the two-electrode horizontal fillet gas shielded arc welding method,
Using a solid wire for welding as the leading electrode and a flux-cored wire for welding as the trailing electrode,
The distance between the electrode between the leading electrode and the trailing electrode is 10 to 40 mm,
The torch angle with respect to the lower plate of the leading electrode and the trailing electrode is 40 to 60 °,
The receding angle of the leading electrode with respect to the welding direction is 1 to 25 °,
The advance angle of the trailing electrode with respect to the welding direction is 1 to 25 °,
The wire diameter of the leading electrode and the trailing electrode is 1.2 to 2.0 mm,
And the wire diameter of the leading electrode is not more than the wire diameter of the trailing electrode,
A two-electrode horizontal fillet gas shielded arc welding method, wherein welding is performed at a total of 400 to 1000 A of the leading electrode current and the trailing electrode current. The welding flux-cored wire is in mass% with respect to the total mass of the wire, and contains 3.5 to 8.5% of the total slag forming agent in the flux.
The two-electrode horizontal fillet gas shielded arc welding method according to claim 1, wherein the balance is iron powder, alloy powder and inevitable impurities.

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