The invention relates to a twin wire welding apparatus (1) including a first contact tube (2) for guiding a first consumable electrode (4) toward a weld puddle (6) and transferring welding current to the first consumable electrode (4), a second contact tube (10) for guiding a second consumable electrode (12) toward said weld puddle (6) and transferring welding current to the second consumable electrode (12), and a single power source (16) connected to said first and second contact tubes (2,10) for providing the same potential to said two consumable electrodes (4,12), and to a method for operating such an apparatus.

A welding apparatus and a method for welding

PROBLEM TO BE SOLVED: To provide a submerged arc welding method capable of obtaining the beautiful bead appearance while obtaining the sufficient penetration at high welding speed with low heat input. SOLUTION: At least one of the inner surface welding and the outer surface welding is executed with the one-layer welding at the welding speed of ≥180 cm/min under the condition that the current density of the first and second electrodes satisfy the inequalities (1), the first electrode and the welding speed satisfy the inequality (2), and the total of the thickness of the steel material and the total groove sectional area of the inner surface and the outer surface satisfy the inequality (3). Inequality (1) : 95≤D 1 ≤3.3×D 2 , inequality (2) : v+0.1×I 1 ≤310, and inequality (3) : 3.9×t-S total ≤20, where D 1 : current density (A/mm 2 ) of the first electrode, D 2 : current density (A/mm 2 ) of the second electrode, v: welding speed (cm/min), I 1 : first electrode current (A), t: thickness (mm), S total : total groove sectional area (mm 2 ) of inner and outer surfaces. Preferably, the distance between the wire centers of the first and second electrodes measured at the surface position of the steel plate is set to 15-45 mm. COPYRIGHT: (C)2011,JPO&INPIT

Submerged arc welding method of steel material

PROBLEM TO BE SOLVED: To provide a submerged arc welding method for a steel material which is suitable to use for pipe-making welding of a large diameter steel pipe such as a UOE steel pipe and a spiral steel pipe. SOLUTION: When welding the inside and the outside of a steel plate by one layer welding, in at least one side of internal welding and external welding, welding conditions are selected so that the relationship between plate thickness and bead width which is measured on the surface layer of the steel plate, satisfies expression (1): 0.40≤W 1 /t≤0.65 and the relationship between the plate thickness and the bead width which is measured in a position at the depth of 0.4t from the surface layer of the steel plate, satisfies expression (2): W 2 /t≤0.34 [wherein t is the plate thickness (mm), W 1 is the bead width (mm) which is measured on the surface layer of the steel plate and W 2 is the bead width (mm) which is measured in the position of 0.4t in the plate thickness direction from the surface layer of the steel plate]. COPYRIGHT: (C)2009,JPO&INPIT

Submerged arc welding method for steel material

PROBLEM TO BE SOLVED: To provide a multi-electrode submerged arc welding method that is suitable for welding in pipe manufacturing of a large diameter welded steel pipe for the purpose of a natural gas/crude oil transporting line pipe or a structural pipe, for example. SOLUTION: This is a multi-electrode submerged arc welding method of three or more electrodes for which the welding wire for the first and the second electrode has a wire diameter ≤3.2 mm and the welding speed ≥80 cm/min. The atmospheric air component between pre-spray flux particles is substituted for a gas containing no N 2 , and a part from the front edge of the flux spray position to the rear of the molten pool is covered with a sealed cover for preventing mixing of the atmospheric air. For instance, when the part from the front edge of the flux spray position to the rear of the molten pool is covered with the sealed cover for preventing mixing of the atmospheric air, a distance L from the tip end to the rear side of a welding wire projected part of the last electrode is designed to satisfy at least an expression (1): L≥2+0.04×v (wherein v is a welding speed [cm/min]). COPYRIGHT: (C)2010,JPO&INPIT

Multi-electrode submerged arc welding method

This invention relates to whole digital buried arc welding varying wire feed control method, which adopts series three-loop control structure with inner one as current ring, second ring as rotary speed ring and outer ring as arc voltage ring with one adjustor in each ring for arc voltage, rotation speed and current. It adopts high speed digit signals processor as central control part to form whole digital DC servo motor control system whose all control strategies area realized by software and the hardware completes digital trigger function and signal process function.

Full-digital speed change control method for wire feeding for submerged arc welding

PURPOSE: To facilitate a bead formation under the effect of gravity that a high speed welding is difficult due to the increase in the input by adequately setting the welding current and wire extension according to the wire diameter and by obtaining the stabilized state available for submerged arc welding. CONSTITUTION: The first electrode is connected to the power source 4a having DC constant voltage characteristic and the second and third electrodes to the welding electrode 4b having AC dropping characteristic respectively by feeding at high speed with a feeding roller 3 the fine diameter wire 1 of about 1.0W1.6mm. The wire 1 then receives the feed of the input which is from the welding power source with keeping the prescribed intervals 6 by the electrode tip 5 for twin wire. For the while the distance 7 between electrodes is kept in 10W50mm. The second and third electrodes are then connected to the dropping characteristic of the AC welding power source. The submerged arc welding is performed under the high speed low heat input welding conditions by setting the welding current at 250W500d 2 A and the wire extension of the wire 1 in 15W40d with said constitution. COPYRIGHT: (C)1986,JPO&Japio

Multiple electrode submerged arc welding method

PURPOSE:To perform submerged arc welding of a thick-walled material having a curved surface with high efficiency by disposing parallelly >=2 final electrodes among >=3 electrodes at an adequate space roughly orthogonally to a weld line and maintaining an adequate space from the electrode just before the same. CONSTITUTION:Final electrodes 4, 4' consisting of two poles are spaced at 5- 20mm. and are disposed parallelly roughly orthogonally to a weld line in single layer build-up welding on both sides which is circumferential welding for a thick-walled object to be welded having a curved surface and uses >=3 electrodes. The electrodes 4, 4' are spaced from the electrode 3 just before the same at 5-40mm.. The upper part is covered with a flux 2 and an arc 5 is generated. A material 1 to be welded and consumable electrodes 3, 4, 4', etc. are melted and mixed, thereby forming a molten pool 6 covered by molten slag 7. If such electrodes are moved, the welding at an adequate width and depth of penetration is accomplished at a high speed.

Multielectrode submerged arc welding method

PURPOSE: To obtain sound weld beads by feeding a filler wire whose feed speed is controlled according to detected information on a groove shape of material to be welded to a first electrode arc to control both prescribed penetration and quantity of reinforcement of weld at the same time CONSTITUTION: In three-electrode submerged arc welding, for instance, groove position and groove shape detectors 14 and 15 calculate continuously the groove position and shape information which are collected to a controller 16 The groove cross-sectional area is then calculated from the information and compared with a reference value and when the former is larger than the latter, the filler wire 12 speed corresponding to the groove cross-sectional area by the difference is calculated and its output signal is given to a feed motor 13 The wire 12 has 16-32mm diameter and a part of a current of the first electrode are is caused to flow thereto When the wire 12 is fed to the first electrode arc 2 from the front, the arc 2 ignited between the material 1 to be welded and a first electrode wire 6 is also ignited on the wire 12 and the arc is transferred slightly above from the groove bottom and the penetration is controlled COPYRIGHT: (C)1990,JPO&Japio

Consumable electrode arc welding method

PURPOSE: To prevent the generation of an undercut and to enable the high speeding by forming the wire diameter of the first electrode in one piece with the specified diameter and those of the final and immediately before electrode in two pieces with the specified diameter and by specifying the range of the using current. CONSTITUTION: One piece of larger diameter wire more than 2.4mmϕ is used for the welding wire 1, 2 to be used by the first electrode 7-1 and second electrode 7-2. The final electrode 7-4 and immediately before electrode 7-3 thereof are composed of two pieces of welding wires in 1.0W1.6mmϕ. The electrodes are arranged so that the arc of each electrode becomes an independent welding arc inside the same molten pool 11. The welding is performed with the using current range as 300W1,000A as well. The sound bead quality having the necessary penetration is obtd. with preventing the generation of undercuts in high speed welding. COPYRIGHT: (C)1987,JPO&Japio

Multielectrode high speed submerged arc welding method

PURPOSE: To reduce the occurrence of a defective product by providing a signal converter provided with AC current and voltage transducers and low-pass filters to detect the occurrence of abnormality based on a comparison between its output value and set upper and lower limit values. CONSTITUTION: A shunt device 2 is provided to a welding power source 1 and connected to an amplifier 3 provided with a low-pass filter. Current transformers 7 and 8 are arranged in the middle of output cables of an AC power source 5 to share a welding head 4 with a DC power source and an independent AC power source 6 and terminals thereof are connected to AC transducers 9 and 10. Further, an amplifier 18 with a low-pass filter and AC voltage transducers 19 and 20 are arranged. Since a signal is subjected to A/D conversion by using the transducers, the averaging processing and data collecting time are remarkably reduced. By this method, since the occurrence of abnormality of the current, voltage, etc., is detected rapidly, the occurrence of the defective product is reduced. COPYRIGHT: (C)1989,JPO&Japio

Shigeo Fujimori

Papers

Multiple electrode submerged arc welding method

Multielectrode submerged arc welding method

Consumable electrode arc welding method

Multielectrode high speed submerged arc welding method

Welding abnormality detector