KR100264745B1 - Apparatus and method for one side welding of curved steel plates - Google Patents

Abstract

Automatic mimic welding of curved workpiece improvement, improvement of welding productivity, welding workability, crack resistance improvement, back bead registration, formation of high toughness welds at dry operation; X traveling wheel Y1; Y traveling on it (4); A base 2 loaded therein and rotatably supported about a vertical Z axis, and a mechanism 12 for elevating and driving in these Z directions; A θ turning mechanism 10 for rotating the base 2 about the Z axis; A biaxial potentiometer P3 supported by the base 2 and detecting a deviation in the Z position and the θ direction of improvement; Biaxial potentiometer P2 which detects the deviation of the Z position and (theta) direction of the same improvement in front of this; And welding torches 30L and 30T supported by the base 2 for improvement. It is provided. According to the detected values of P2 and P3, the bend and the forward and backward inclination α of the improvement are calculated, and the base 2 is corresponding to these by the θ turning mechanism and the Z lifting and driving. Auto adjust. The left and right tilts of the workpiece are detected by P5 and P4 and the center position of the oscillate is adjusted.

The angle of improvement is set to 30 to 65 °, the backing material is placed on the back side of the improvement, and the granules or iron are filled in the improvement to the height of 1/4 to 2/3 of the plate thickness of the welded material, and the preceding welding electrode wire is 40 -150 times / minute, the trailing welding electrode wire is shaken at 30 to 120 times / minute, and the welding current density of the preceding electrode is 200 A / mm ² or more, and the welding current density of the trailing electrode is 150 / mm ² or more. The interpolar distance of the trailing electrode is welded to 100 to 600 mm.

Description

One side welding device and method of curved plate

The present invention is a device that three-dimensionally mimics the improvement formed by the curved weld material and the amount of spatter generated during welding using this device is small, at the same time good crack resistance and bead appearance, high toughness welding A high efficiency two-electrode single-sided gas shielded arc welding method for forming beads. In particular, although not intended to be limited thereto, the present invention relates to a one-sided welding of curved steel panels that are covered by shells such as bows or sterns of the hull.

For example, in shipbuilding, several steel panels (for example, 15m × 20m) are struck and welded on one side to manufacture the outer shell of the hull. However, in case of welding steel panels that are covered to the curved shape after welding, such as the appearance of bow or stern, each panel is bumped against each other while supporting from below with hydraulic jack so as to be required curvature. In other words, the improvement is welded from above. The improvement in this case extends along the curved surface of the outer plate to be formed and has a three-dimensional bend. When welding such an improvement, since the automatic welding device which presupposes welding the improvement of a linear form cannot be used, conventionally, there are many welding operations by one hand.

Welding work by three-dimensionally bent one hand requires time and space for securing the footrest of the operator and disposing of the welding equipment, and it takes longer welding work time and lower productivity of welding work than in the case of straight-lined welding. . Due to the degree of bending of the improvement and the superiority of the skill of the welding worker, it is easy to cause dispersion in the welding quality, and much effort is required for the rest. Therefore, the welding cost is high.

In recent years, the application of the gas-sealed arc welding method is rapidly increasing in various fields in order to reduce the welding cost and increase the efficiency in the construction of various welding structures. Among them, application in fields such as shipbuilding or bridges where the ratio of butt welding is high is remarkable. However, from the viewpoint of reducing the overall cost of welding, high speed single-sided welding from short to long has become a major problem.

As a single-sided welding method, the submerged arc welding method has always been studied as a sheet metal welding of shipbuilding. For example, the submerged arc welding method disclosed in Japanese Unexamined Patent Application Publication No. 60-59072 prevents the reduction of the weld bead melting depth and the deterioration of the bead appearance, which is accompanied by electrode fluctuations, and also prevents cracking in superlayer beads. I'm trying to. However, this submerged arc welding method has a problem that the implementation equipment becomes large and it is complicated in short welding and cannot be applied.

In addition, the high current density gas-sealed downward welding method using flux wires presented in Japanese Unexamined Patent Publication No. 61-49027 uses a narrow diameter composite wire, and the wire extruding length is added in one direction to lower the high current solid-state welding speed. Welding is performed at high efficiency and the welding cost is reduced. However, since the wire extruding length is long, from 35 to 70 mm, there are problems such as misalignment of the target position due to poor sealing or habit of bending the wire, and crack of superficial beads during single side welding.

Japanese Unexamined Patent Application Publication No. 50-7543 discloses filling an appropriate amount of steel granules or iron in an improvement made in contact with a backing material, and welding while shaking the narrow wire. However, this method does not provide a good welding without the improvement gap, and the improvement angle is also large.

Moreover, none of the above methods leads to the automation and practical use of the improved welding formed by the curved weld material.

The first object of the present invention is to automate the welding operation of the bent improvement, and the second object is to improve the welding productivity of the three-dimensionally bent improvement, and the welding of the three-dimensionally bent improvement is high quality and low. Let it be the cost as a 3rd objective. The fourth object of the present invention is to obtain a healthy and high toughness weld by improving welding workability, crack resistance and flattened bead of single-sided welding of a long welded structure by shortening the welded material on the curved surface.

1 is a perspective view of the welding apparatus 1 implementing the present invention as one embodiment, as viewed from an oblique upper side, and the mechanism elements are shown in a simplified manner.

FIG. 2 is a side view of the welding apparatus 1 shown in FIG. 1 as seen from the dashed-dotted arrow 2A direction shown in FIG. 1, with a portion showing a cross section.

FIG. 3 is a front view of the welding apparatus 1 shown in FIG. 1 as seen from the dashed-dotted arrow 3A direction shown in FIG. 1, with a portion showing a cross section.

4 is a reduced side view corresponding to FIG. 2, and schematically shows the schematic positions of potentiometers Pl to P5 and P7 and rotary encoder P6, which are electric motors and sensors for driving various mechanisms.

FIG. 5 is a diagram showing the required left and right tilt β and the required shift amount d × β between the oscillate centers shown in FIG. 3, and the workpieces W1 and W2 show cross sections in a direction traversing the improvement.

FIG. 6 is a perspective view of the workpieces W1 and W2 shown in FIG. 1, and shows the detection directions of the workpieces W1 and W2 of the potentiometers P2 to P5 shown in FIG.

FIG. 7 is a plan view showing the positional relationship between the moving direction and the moving speed (welding degree) V of the sensor base 2 and the improvement (b) with respect to FIG.

FIG. 8 is a perspective view showing an overview of the workpieces W1 and W2 shown in FIG.

9 is a flowchart (main routine) showing the control operation of the control circuit 8 shown in FIG.

FIG. 10 is a flowchart showing the "welding" content (subroutine) of step 4 shown in FIG.

11 is an enlarged longitudinal sectional view of the double shield 20 provided in the welding torch 30L shown in FIG.

FIG. 12 (a) is an enlarged front view showing V improvement between the welded materials W1 and W2 shown in FIG.

FIG. 12 (b) is an enlarged front view showing the improvement in the case where the welded materials W1 and W2 are Y-improved.

FIG. 13 is a graph showing the distribution of the combination of the plate thickness and the rigid scattering height when the improved welded material of several plate thicknesses is welded under the welding conditions shown in Table 3. FIG. I have attached a symbol to show.

FIG. 14 is a side view showing the distance between the leading electrode wire wa1 and the trailing electrode wire wa2 of the welding apparatus 1 shown in FIG.

15 is a graph showing the relationship between the welding current value and the spatter generation amount, and the conventional method shows the case of a single shield.

* Explanation of symbols for main parts of the drawings

1: welding device 2: sensor base

3: torch support frame 4: Y driving truck

4a to d: Wheel 5: Wire feed device

6: welding chip 8: control circuit

9: pendant 10: pivot

12: lifting plate 13a to c: rail

14 tube 14a outlet

20: double shield 21: attachment

22: inner nozzle 23: outer nozzle

30L, 30T: welding torch 31a: rotating shaft

b: improvement F: level surface

M1 to M11: Motor M4s: Threaded rod

X1, X2: X direction rail RX: X rail stand

Y1, Y2: X travel stand Yz: support pillar

RY: Y direction rail O: Center of rotation

P1 to P5, P7: Potentiometer P6: Rotary Encoder

W1, W2: Work (welded material) wa1, wa2: Welding electrode wire

wp: wirepack

The one-side welding device of the curved sheet of the present invention,

An X traveling platform Y1, Yz, RY and Y2 having an X traveling motor M1 driven according to an X current order and traveling in the horizontal X direction;

Y having a Y travel motor M2 supported by the X travel platforms Yl, Yz, RY, and Y2 and driven according to the Y current order, and traveling in the Y direction perpendicular to the X travel platform with respect to the X travel platform. Traveling table 4;

A base 2 rotatably supported in the Y direction 4 in a vertical Z direction and rotatably supported about a vertical Z axis 0;

A Z lifting mechanism 12 which is driven according to a Z current order and includes a lifting motor M4 for driving the base 2 in a vertical Z direction;

a turning mechanism 10 comprising a first rotating motor M3 which is driven according to a current carrying order and drives the base 2 to rotate about a vertical Z axis 0;

First detection means (P3) supported by said base (2) for detecting a Z position of an improvement on an extension line of the rotation center axis (0) and a position in a direction perpendicular to the Z direction;

Second detecting means (P2) supported by the base (2) and detecting a Z position of an improvement and a position perpendicular to the Z direction at a position away from the rotation center axis (0) by a predetermined distance; And welding torches 30L and 30T for welding the improvement supported on the base.

In addition, in order to facilitate understanding, the reference numerals in the parentheses refer to corresponding elements or symbols of substantial parts of the embodiments shown in the drawings and described later.

According to this, the three-dimensional (X, Y, Z) of the base 2 is formed by the X traveling platform RY traveling in the horizontal X direction, the Y traveling platform 4 traveling in the Y direction, and the Z elevating mechanism 12. You can set or adjust the position of. However, when the base 2 supports the welding torch, the welding torch (base) can be driven according to the three-dimensional distribution of the welding torch, but the posture of the welding torch for improvement is due to the bending of the improvement. There may be a deviation from the basic posture. Since the welding apparatus of the present invention has a θ turning mechanism 10 which drives the base 2 to rotate about the vertical Z axis 0, the welding apparatus 10 can be improved by using the θ turning mechanism 10 in response to the bending of the improvement. The welding torch (base) can be pivoted so that the welding torch maintains the reference position at all times.

Further, in the present invention, the bending θ and the improvement of the improvement in the direction crossing the direction in which the improvement (b) of the welded materials W1 and W2 extend from the detection values of the first and second detection means P3 and P2 are improved. The inclination α with respect to the horizontal plane in the extending direction is calculated from the detection values of the first and second detection means, and the base 2 is pivotally driven through the θ turning mechanism 10 corresponding to the bending θ 'to correspond to the inclination α. Can move the base 2 up and down via the Z lifting mechanism 12. This realizes the welding of the curved automatic imitation in which the welding torch mimics the bend θ '(orbital direction) of improvement and the forward and backward inclination α.

Embodiment of the Invention

A torch support frame (3) rotatably supported on the base (2) about a horizontal X axis to support welding torches (30L, 30T); And a Y rotation mechanism including a second rotation motor M7 for rotationally driving the torch support frame 3 about the horizontal axis 31a according to the? In this way, the torch support frame 3 is rotated by the Y rotation mechanism in response to the front and rear inclination α, so that the front and rear angles γ of the torch to the welded materials W1 and W2 are bent in the forward and backward directions of the contacted materials. Can be kept substantially constant.

The torch support frame 3 supports the welding torches 30L and 30T so as to be foldable with respect to the welded material W1 and W2, and the device further folds the welding torches 30L and 30T in response to the folding current command. And a torch upper and lower gear including torch upper and lower motors M8 and M10. According to this, welding torch 30L, 30T can be fold-driven through torch up-and-down motors M8 and M10 corresponding to inclination (alpha), and it can maintain a welding torch at the fixed distance for improvement. The torch support frame 3 reciprocates the welding torch 30L, 30T with respect to the welded material W1, W2 in the direction orthogonal to the vertical line connecting the first detection means P3 and the second detection means P2. The first to-be-welded material W1 and the second to-be-welded material which are movably supported, and the apparatus is further supported by the said base 2, and are relatively separated in the direction orthogonal to the said longitudinal line, respectively, and constitute an improvement. Third detecting means P5 and fourth detecting means P4 for detecting the Z position of the surface of W2); And an oscillate mechanism including oscillate motors M9 and M11 that reciprocately drive the welding torches 30L and 30T in accordance with the oscillate conduction order. According to this, the inclination β with respect to the horizontal plane of the welded material in the direction orthogonal to the direction in which the improvement (b) extends is calculated from the detection values of the third and fourth detection means P5 and P4, and the oscillates corresponding to the inclination β. The amplitude center of the oscillate reciprocating drive of the welding torches 30L and 30T by the mechanisms M9 and M11 can be set aside to mimic the center of amplitude as an improvement center.

The apparatus further comprises a control means 8; The control means 8 determines the bend θ 'of the improvement in the direction crossing the direction in which the improvement b of the welded materials W1 and W2 extends and the inclination α of the horizontal plane in the direction in which the improvement extends. Calculated from the detection values of the first and second detection means P3, P2,

The inclination β with respect to the horizontal plane of the welded materials W1 and W2 in the direction orthogonal to the direction in which the improvement (b) extends is calculated from the detection values of the third and fourth detection means P5 and P4, and bent θ '. Correspondingly to the pivoting drive of the base 2 through the θ turning mechanism 10,

In response to the inclination α, the base 2 is driven up and down via the Z lifting mechanism 12,

In response to the inclination α, the torch support frame 3 is rotated through the γ rotation mechanism M7,

In response to the inclination α, the welding torches 30L and 30T are fold-driven through the torch upper and lower openings M8 and M10,

Corresponding to the inclination β, the amplitude center of the oscillate reciprocating drive of the welding torches 30L and 30T by the oscillate mechanisms M9 and M11 is set aside.

By this, the welding torches 30L and 30T are imitated at the bend θ '(orbital direction) of improvement and the front and rear inclination α, and the front and rear angles γ of the torch with respect to the welded materials W1 and W2 are the front and rear directions of the welded materials. In spite of the bend of α, it is substantially kept constant and the welding torches 30L and 30T are folded against the improvement in correspondence to the inclination α so that the welding torch is kept at the predetermined distance for the improvement and at the same time corresponding to the inclination β The amplitude center of the oscillate reciprocating drive of the welding torches 30L and 30T by the oscillate mechanisms M9 and M11 mimics the center of improvement. That is, curved automatic imitation welding is realized.

Therefore, it is unnecessary to secure a footrest of the operator for the welding work by the one-handed improvement of the three-dimensional bend, to arrange the welding equipment, and to save time and space required for these. The dispersion of welding quality due to the bending of improvement and the superiority of the skill of the welding worker is reduced, and the effort of the remaining care is reduced. Therefore, the welding cost is reduced.

The one-sided welding method of the curved sheet of the present invention uses a single-sided welding device of the curved sheet described above to imitate the improvement between the welded materials on the curved surface with a pair of welding torches, wherein V or the temporary surface of the inner surface of the curved welded material is temporarily applied. The improvement angle of improvement of Y shape shall be 30-65 degrees,

If it is an improvement, a backing material is put, and the granulation or iron is filled in the improvement to the height of 1/4 or more and 2/3 or less of the plate thickness of the welded material,

The welding current density of the preceding and following welding electrode wires is 100mm or more and 600mm or less, and the welding current density of the electrode wire to be welded before is 200A / mm ² or more, and the welding current density of the electrode wire to be welded at the same time is 150A / mm ² At the same time

It is characterized by rocking and driving the preceding electrode wire at 40 times / minute or more and 150 times / minute or less, and the following electrode wire at 30 times / minute or more and 120 times / minute or less.

The trailing weld electrode wire of the preferred embodiment is in weight percent relative to the total weight of the wire;

TiO ₂ : 2.5% or more and 7.0% or less

ZrO ₂ : 0.4% or more and 1.0% or less

Al ₂ O ₃ : 0.1% or more 1.0% or less

Si: 0.2% or more and 1.2% or less

Mn: 1.0% or more and 4.0% or less

Mg: 0.1% or more and 1.0% or less

The fluxes containing and containing the fluxes in which the total of one or two species of Na and K are 0.03% or more and 0.3% or less are wires.

The trailing welding electrode wire of the preferred embodiment is, furthermore, in weight percent relative to the total weight of the wire;

Ni: 0.3% or more and 3.0% or less

Ti: 0.02% or more and 0.2% or less

B: 0.002% or more and 0.015% or less

Flux-filled flux containing the wire is a wire.

In a preferred embodiment at least the preceding electrode wire is double shielded with a first shield gas and a second shield gas.

Other objects and features of the present invention will become apparent from the following description of the embodiments with reference to the drawings.

EXAMPLE

With reference to FIG. 1, FIG. 2, and FIG. 3, the outline | summary of the single-sided gas shielded arc welding apparatus used for implementation of this invention is demonstrated. 1 to 3, the Z arrow direction is in the upward direction and the X arrow and Y arrow directions are in the horizontal direction. In the following description, the Y arrow direction is represented by the forward direction and the X arrow direction is represented by the right direction. FIG. 1 is a simplified diagram showing an outline of a mechanism corresponding to a perspective view of the welding device 1 viewed obliquely from above. The workpieces (welded materials) W1 and W2 are formed by a plurality of hydraulic jacks (not shown) provided on F when the work floors are in contact with each other as shown in FIGS. 5 and 6 (a). It is supported downward and has a desired curved shape by adjusting the support of each jack. That is, it is bent in three dimensions. The improvement (b) generated between the edges and the edges of the workpieces W1 and W2 is three-dimensionally bent at the required angles of the workpieces W1 and W2. In order to maintain such a curved shape, the improvement inner surface is temporarily pasted by temporary paste welding. In FIG. 1, the X-direction rail X1 extending in the horizontal X direction is provided on the floor surface F, and is located above the rail X1 (away from the floor surface F), and the rail X1. The X-direction rail X2 parallel to it is supported by the support column which is not shown in figure. Set the two rails (X1 and X2) to the X rail band (RX). The X travel platform Yl is placed on the rail X1, and the X travel platform Y2 is placed on the rail X2. The X travel platforms Y1 and Y2 are supported by the support column Yz and the Y direction rail RY. ). The support column Yz and the Y direction rail RY are orthogonal and integrally continuous. The drive wheel of the X traveling platform Y1 is rotated through a speed reduction mechanism (not shown) by the motor M1 mounted on the X traveling platform Y1. The motor M1 is energized, the driving wheel of the X traveling platform Y1 is driven to rotate, and the X traveling platform Y1 travels on the rail X1, and the support column Yz and the Y direction rail RY It moves to the left or right in the X direction in a state parallel to the Y axis along the rails X1 and X2.

The wheels 4a to d of the traveling trolley (Y traveling platform) 4 of the welding device 1 are placed on the Y-direction rail RY. A sprocket wheel (not shown) is firmly attached to the rotation shafts of the wheels 4a to d of the traveling trolley 4, and a wheel-shaped chain belt (not shown) disposed along the rail RY is engaged with the sprocket wheel. . The chain belt is rotationally driven by the motor M2 mounted on the traveling trolley 4 so that the traveling trolley 4 moves on the rail RY in the Y direction.

FIG. 2 shows the welding device 1 shown in FIG. 1 as viewed by the dashed-dotted arrow 2A, and FIG. 3 shows the welding device 1 shown in FIG. 1 by the dotted line 3A. The figure seen from the direction is shown. A hole penetrating up and down is opened in the center portion of the travel truck 4, and the elevating pipe 12 of the columnar shape is freely raised and lowered in the Z direction through the hole. Rails 13a to c extending in the Z direction are attached to the outer surface of the elevating pipe 12, respectively, and they are freely mounted in the Z direction on a slider provided on the inner surface of the hole of the traveling cart 4 facing it. . A lifting motor M4 for rotationally driving the screw rod M4s extending in the Z direction is firmly attached to the outer wall of the lower portion of the lifting pipe 12. The running trolley | bogie 4 has the screw hole which penetrates a trolley | bogie part in a Z direction, and this screw hole and the screw rod M4s are screwed together. Since the traveling truck 4 is supported by the Y rail RY downward, when the lifting motor M4 rotates the screw rod M4s, the lifting pipe 12 moves in the Z direction with respect to the traveling truck 4. Go up and down.

The hollow pivot shaft 10 which extends the shaft center of the elevating pipe 12 in the Z direction passes horizontally freely. The rotary motor M3 is firmly supported on the outer wall near the upper opening of the elevating pipe 12 protruding from the upper surface of the traveling truck 4. A spur gear is fixed to the rotating shaft of the rotating motor H3 and rotates in the horizontal direction. A spur gear is integrally formed at the edge of the upper opening of the pivot shaft 10, and the spur gear of the rotary motor M3 meshes with this gear. When the rotating motor M3 is energized, an integral spur gear rotates on the rotation side thereof, and the pivot shaft 10 rotates about the center of rotation line 0 with respect to the elevating pipe 12 through the gear.

The sensor base 2 is supported by the lower end part of the pivot shaft 10. Accompanying the rotation of the pivot shaft 10, the sensor base 2 rotates in the horizontal direction. The rotary shaft of the potentiometer P1 is connected to the rotary shaft of the rotary motor M3, and the potentiometer P1 generates an electrical signal representing the pivot angle θ of the pivot shaft 10.

In the position of the rotation center line 0 of the lower part of the sensor base 2, the 1st improvement which is free to move to the horizontal direction orthogonal to this center line 0 (direction perpendicular to the ground in FIG. 2, X direction in FIG. 3), and Z direction There is a copying roller, and a biaxial potentiometer P3 is coupled to the first improved copying roller. The potentiometer P3 has a potentiometer for detecting the horizontal position between the supports for freely supporting the first improved patterning roller, and a potentiometer for detecting the Z position between the supports and the position of the rotation center line 0. Generates an electrical signal indicative of the horizontal position and the Z position of the improvement relative to the sensor base 2 (FIG. 2).

At a position away from the rotational center line 0 of the lower part of the sensor base 2, a second improved imitation roller free to move in the horizontal direction (the direction perpendicular to the ground in FIG. 2 and the X direction in FIG. 3) and the Z direction is provided. A biaxial potentiometer P2 is coupled to the second improved imitation roller. The potentiometer P2 also has a potentiometer for detecting the horizontal position between the supports for freely supporting the second improved imitation roller, and a potentiometer for detecting the Z position between the supports, and has a rotational center axis of zero. An electric signal indicating the horizontal position and the Z-direction of improvement with respect to the sensor base 2 at a position away from the predetermined distance is generated (FIG. 2).

The difference in the horizontal position detected by the potentiometers P3 and P2 corresponds to the horizontal bend (angle angle) of the improvement relative to the sensor base 2 (horizontal reference theory), and the potentiometers P3 and P2 The difference of the Z position detected by) corresponds to the inclination angle (front and rear angle) α (figure 2) of the improvement line with respect to the horizontal plane.

There is a first work mimic roller at a position separated by a predetermined distance from the longitudinal line connecting the first and second improved mimic rollers P3 and P2 in the lower part of the sensor base 2 and the rotation center line 0, and the roller is rotated freely. The potentiometer P5 detects the Z position between the supporting supports, and generates an electric signal indicating this Z position (FIG. 3). In addition, there is a second work mimic roller at a position perpendicular to the vertical line at the lower part of the sensor base 2, away from the rotation center line 0 by a predetermined distance, and at the same time facing the first work mimic roller with respect to the rotation center line 0. The potentiometer P4 detects the Z position between the supports for freely supporting the roller, and generates an electric signal indicating the Z position (FIG. 3). The difference between the Z positions detected by the potentiometers P5 and P4 corresponds to the inclination angle (left and right) β of the workpiece with respect to the horizontal plane (FIG. 3).

The rotary encoder P6 is coupled to the first work mimic roller P5, and generates an electric signal of one pulse with respect to the rotation of the predetermined angle of the roller P5. By counting these pulses, the movement amount according to the improvement of the sensor base 2 can be known, and the count-up value between predetermined times shows the speed V (connection degree) of the movement according to the improvement of the sensor base 2.

Referring to FIG. 2, the rotation axis 31a extending in the arrangement direction (direction perpendicular to the paper surface of FIG. 2) of the first and second work mimicking rollers P5 and P4 is approximately the center of the sensor base 2. It penetrates freely. The sensor base 2 has a motor M7, and if its output shaft is connected to the rotating shaft 31a through the reduction mechanism and the motor M7 is energized, the rotation of the rotating shaft of the motor M7 is decelerated by the reduction mechanism. And is transmitted to the rotating shaft 31a. The torch support frame 3 is fixed to the rotating shaft 31a. Accompanying the rotation of the rotary shaft 31a, the torch support frame 3 rotates about the rotary shaft 31a, and the front and rear angles γ of the welding torches 30L and 30T supported by the frame 3 change. . The potentiometer P7 generates an electric signal representing the rotation angle of the rotation shaft 31a.

The welding torch 30L includes a folding mechanism including a motor M8 for pushing and pulling (torting) the torch, and an oscillate for oscillating the welding torch 30L in the width direction of the improvement. The torch support frame 3 is supported by the torch support frame 3 via the oscillate mechanism including the motor M9 so as to be able to be lifted (folded) in the longitudinal direction of the improvement and oscillated in the width direction of the improvement. The welding torch 30T also includes a folding mechanism including a motor M10 for pushing and pulling (torting) the torch, and an oscillate motor M11 for oscillating the welding torch 30T in an improved width direction. The torch support frame 3 is supported by the torch support frame 3 via an oscillating mechanism including a) so as to be able to be lifted (folded) in the longitudinal direction of the improvement and oscillated in the width direction of the improvement.

The sensor base 2 furthermore has a wire feeder 5. The wire supply device 5 consists of two sets of wire feeders and motors M5 and M6 for driving them. The two welding wires wa1 and wa2 pass from inside the pipe 14 passing through the axial center portion of the pivot shaft 10 in the Z direction from the wire pack wp mounted on the upper portion of the traveling cart 4. It is supplied to the wire supply apparatus 5 from the discharge port 14a of 14, passes through the wire feeder therein, and is supplied to the welding torch 30L, 30T, respectively.

When welding is started, the motors M5 and M6 drive the wire feeders, and supply the wires wa2 and wa1 from the wire pack wp to the welding torches 30L and 30T, respectively. The motor M8 of the welding torch 30L adjusts the protruding length (distance from the improvement b) of the welding torch 30L to a predetermined value (based on the power supply command from the control circuit to be described later). M9) oscillates the welding torch 30L at a speed corresponding to the welding speed (V). The motor M10 of the welding torch 30T adjusts the protruding length (distance from the improvement b) of the welding torch 30T to a predetermined value (based on the power supply command from the control circuit described later), The motor M11 oscillates the welding torch 30T at a speed corresponding to the welding speed V. FIG.

4 shows arrangements and functions of the respective motors M1 to M11, potentiometers P1 to P5 and P7, and rotary encoder P6. Table 1 shows the driving objects of the motors M1 to M11 described above, and Table 2 shows the detection objects of the potentiometers Pl to P5 and P7 and the rotary encoder P6 described above. A to D in Table 15 are values adjusted according to the working environment.

The energization control of the forward and reverse rotations of the respective motors M1 to M11 is performed by the operator at the initial setting through the pendant 9 (FIG. 3) which can be detachably mounted in the vicinity of the sensor base 2, When welding starts, the control circuit 8 in the pendant 9 performs it automatically, referring to the detected value of P1-P7. In the sensor base 2, there is a motor driver for driving each motor, respectively, and the current order given from the pendant 9 is transmitted to these motor drivers, and each motor driver is assigned to the current order given from the pendant 9. Therefore, the motors connected to each of them are driven.

The control circuit 8 is welded to the improvement b in accordance with the information input from the pendant 9 up to that time when the welding start is given, and the detection values of the potentiometers P1 to P5 and P7 and the rotary encoder P6. Traveling speed of X traveling platform (Yl, Yz, RY, Y2), Y traveling platform 4 which mimics the torch and simultaneously controls the welding torch to the set posture and target position for improvement, and sets the welding speed as the set speed. Control, θ rotation control of the sensor base 2, γ rotation control of the torch support frame 3, extrusion (folding) of the torch, and improved imitation control of the center of the oscillate width are performed.

9 shows a main routine showing the control operation of the control circuit 8. When the power supply is turned on, the control circuit 8 clears all of the internal memory, the counter, and the like in step 1. Then, a lamp (not shown) on the pendant 9 is turned on to indicate that the initialization of the memory has been completed, and the operator waits for input (initialization). At this time, each of the motors M1 to M11 can be driven by an operator in accordance with a key operation on a control panel (not shown) of the pendant 9. In the following descriptions of FIGS. 9 and 10, the word "step" is omitted in parentheses and the step No. Only numbers are shown.

When the operator confirms that the initialization is completed by the lighting of the lamp on the pendant 9, the operator operates the keys on the control panel (not shown) of the pendant 9 to selectively drive (power) the motors M1 to M11. The attitude and distance for the improvement (b) of the welding torches 30L and 30T are determined. In detail,

1. Drive the motors M1 and M2 to move the rotation center line 0 to the sensing start point Op (first, second, and third degrees) on the improvement (b) to drive the motor M4 to drive the sensor base (2). Is lowered, and the first improved imitation roller P3 is placed at this sensing start point (inside the improvement). The sensing starting point is an end of the lower Z position (height) of both ends of the improvement line. Furthermore, the workpieces W1 and W2 are arranged on the floor surface F such that the improvement line is substantially parallel to the Y axis.

2. The motor M3 is driven to pivot the pivot shaft 10 (sensor base 2) so that the second improved mimic roller P2 is in the improvement b in the welding direction forward with respect to the first improved mimic roller P3. Put it.

3. Drive the motor M4 to raise and lower the sensor base 2 so that the first and second improved imitation rollers P3 and P2 are in the improvement, and their Z position is near the center of the Z position movement range, In addition, the first and second work mimic rollers P5 and P4 collide with the work to adjust the height of the sensor base 2 so that their Z position is near the center of the Z position moving range.

4. Instruct start position setting. The control circuit 8 digitally converts and reads the electric signals of the potentiometers P3 and P2 at that time in response to the start posture setting instruction. Then, the sensor base 2 is driven by the motor M3 so that the horizontal position of the potentiometers P3 and P2 (the direction perpendicular to the ground of FIG. 2) becomes the neutral point (horizontal position shift zero). . As a result, the horizontal position of the first improved imitation roller P3 and the second improved imitation roller P2 becomes the reference position (no horizontal displacement) with respect to the sensor base 2, and the two rollers P3 and P2. ), Welding torches 30L and 30T are located on the vertical lines connecting.

5. The motor M7 is driven to drive the welding head 3 by γ rotation, and the angle (front and rear angle γ) in the direction imitating the improvement (b) of the welding torches 30T and 30L is appropriately adjusted.

6. Drive the motor (M5, M6) to supply the welding wire (wa1, wa2) to the welding torch (30T, 30L).

7. Drive the motors M9 and M11 to oscillate the welding torches 30T and 30L and adjust them to the center positions of the oscillate width and the oscillate width in the direction orthogonal to the improvement (b).

8. Drive the motors M8 and M10 to adjust the extrusion length of the welding torches 30T and 30L, that is, the distance between the improvement (b) and the torch tip.

The procedure of 1. to 7. is an example of the procedure of initial setting, and the procedure may be changed, repeated or omitted as needed. Furthermore, the operator inputs the required welding speed Vs through the key on the operation panel on the pendant 9. When the initial setting is completed, the operator performs a key operation indicating that the initial setting is completed on the operation panel on the pendant 9.

The control circuit 8 saves the welding speed Vs inputted to a register, and if there is an input of initial setting completion, digitally converts and reads the electric signals of the potentiometers P1 to P5 and P7 at this time, and simultaneously Save the centers of the rate width and oscillate width to registers. When the horizontal position (direction perpendicular to the ground of Fig. 2) of the potentiometers P3 and P2 is not the neutral point (horizontal position misalignment), the sensor base is connected to the motor M3 as shown in the above. The motor is rotated to (2), and when it is finished, a notification is urged to adjust the above 5. to 8. The horizontal position of the potentiometers P3 and P2 (the direction perpendicular to the ground in Fig. 2) is at the neutral point, and the rotation angle θ represented by the potentiometer Pl and the rotation indicated by the potentiometer P7 Determine whether the angle (γ: torch back and forth angle with respect to the horizontal plane), the protruding length of the torch (folding distance), the oscillate width and the oscillate width center position are appropriate values by checking whether they are within each setting range, and the appropriate values. It informs welding start on the back side. If it is not a suitable value, a notification is issued to urge you to readjust what is not.

Upon notifying the welding start on, the control circuit 8 waits until the welding start instruction by the operator's key operation arrives, and starts welding when the welding start instruction arrives (3). In addition, when the welding is to be stopped, the operator also inputs "welding stop" by the key operation of the operation key of the pendant 9. "Welding stop" is mentioned later.

FIG. 10 shows a subroutine of "welding" in step 4. FIG. Here, the control circuit 8 counts it up whenever the rotary encoder P6 generates one pulse, reads the count up value at a predetermined period, calculates the welding speed V, and saves it in the register to initialize (clear) the count up value (41). At the same time, the electrical signals of the potentiators P1 to P5 and P7 are digitally converted and read (42). The next state information is then calculated (43).

Bending [theta] 'of improvement: Calculation of the bending [theta]' of improvement (b) with respect to the sensor base 2 in the rotation [theta] direction. It calculates from the difference of the position of the horizontal direction which the potentiometers P3 and P2 detected.

Angle before and after improvement α: Calculation of the angle α (figure 2) formed with the horizontal angle of the improvement line directly under the sensor base 2. It calculates from the difference of the Z position which the potentiometers P3 and P2 detected.

Left and right inclination beta of the work piece: Calculation of the inclination angle beta (figure 3) of the work in the direction crossing the improvement. It calculates from the difference of the Z position which the potentiometers P5 and P4 detected.

Thus, calculating the state information θ ', α and β, the control circuit 8 causes the target angle θ = θ of the θ rotation of the sensor base 2 to zero the improvement of the bending θ' with respect to the sensor base 2. by calculating + θ ′

X target speed Vsx = VS cosΘ,

Y target speed Vsy = Vs sinΘ,

X traveling speed Vx = V cosΘ,

Y Travel Speed Vy = V sinΘ

Calculate (44). θ is the detection value of the potentiometer P1.

7 shows the relationship between the moving direction and the moving speed V of the sensor base 2 and the improved line. The component X direction of the moving speed V is V cosΘ and the component Y direction is V sinΘ.

The control circuit 8 then calculates a target value (45). Here, first, the deviation of the X traveling speed Vx with respect to the X traveling target speed Vsx is calculated, and the current carrying target value of the motor M1 for zeroing this deviation is calculated by PID calculation. Similarly, the deviation of the Y running speed Vy with respect to the Y running target speed Vsy is calculated, and the target value of the energizing current of the motor M2 for zeroing this deviation is calculated by PID operation. Furthermore, the detection data of the potentiometers P2 to P5 and P7 read out when the initial setting is completed, the oscillate width, the oscillate width center position, the torch protrusion length (folding distance), and the current read potentiometer ( Based on the detection data of P2 to P5, P7), the target value of the torch front and rear angle γ, the torch protrusion length target, the oscillate width target value, and the oscillation to maintain the relative position and posture between the initial improvement and the substantially same torch value at the initial setting The target width center position target value is calculated.

Fig. 5 shows the required amount of displacement south of the oscillate width center corresponding to the left and right inclinations β of the workpiece d × β. The deviation value of the required deviation amount d × β and the value obtained by shifting the oscillate width center position data at the initial setting as the target deviation amount calculated at this time as the required deviation amount at the initial setting are defined as the target values of the oscillate width.

Next, the control circuit 8 drives M1 to M11 based on the calculated target value (46). In other words, the rotor is driven in accordance with the latest target value. Here, the control circuit 8 drives the motor M4 to raise and lower the sensor base 2 so that the Z position detected by the potentiometer P3 becomes the Z position when the initial setting is completed. The motor M3 is driven so that the detection angle θ of the meter P1 becomes the target angle Θ, and the motors M7 to M are arranged so that the center positions of the torch back and forth angle γ, the torch protrusion length, the oscillate width and the oscillate width are respectively matched with the target values. M11) is driven. The motors M1 and M2 are accelerated and decelerated so that the X running speed Vx and the Y running speed Vy coincide with the target values Vsx and Vsy, respectively.

Then, the control circuit 8 has the operator input the " weld stop " instruction through the operation key on the pendant 9, or has the second improved imitation roller (potentiometer P2) reached the end of the improvement b? (47), the return to Step 5 in FIG. However, when none is established, the process proceeds to step 41 in anticipation of the time-over of the timer that determines the control period, and the next control cycle is started.

When the "welding stop" instruction is input or when the electric signal of the potentiometer 2 indicates the end of improvement, the control circuit 8 executes the end processing of step 5 (FIG. 9), and the welding torches 30L and 30T. ) Stop each motor by stopping welding.

The double shield 20 is attached to each tip of the welding torches 30L and 30T (FIG. 2).

11 shows an enlarged longitudinal section of the double shield 20 mounted on the welding torch 30L. The welding torch 30L feeds the welding wire wa1 into the groove from the welding chip 6 at its tip and simultaneously emits shield gas. The double shield 20 is attached to this welding torch 30L. The double shield 20 includes an attachment 21 fixed to the welding torch 30L, an inner nozzle 22 and an outer nozzle 23 fixed to the attachment 21. The inner nozzle 22 surrounds the welding chip 6 and guides the shield gas (first shield gas) blown out from the welding torch 30L downward along the chip 6. The first shield gas is blown out around the welding wire wa1 exposed to the outside of the chip 6 from the lower end opening of the inner nozzle 22. The outer nozzle 23 is circumferentially widened in the lower half, and the second shield gas G is supplied to the outer nozzle 23 from the outside of the welding torch 30L, which is applied to the outer peripheral surface of the inner nozzle 23. Therefore, it blows outward of the 1st shield gas from a lower opening. The molten portion immediately below the welding wire wa1 is double shielded with the first shield gas and the second shield gas. Hereinafter, the aspect which blows out even the 2nd shield gas by the 1st shield gas is called "double shield", and the aspect which blows out only the 1st shield gas is called "double shielded" or "single shield". .

Next, the above-mentioned welding apparatus 1 of the curved workpieces W1 and W2 (welded material) which is continuously inclined in the welding line direction (Y direction) and inclined at right angles (X direction) perpendicular to it is used. Explain one-sided welding. Moreover, the inclination of the workpiece in the weld line direction (Y direction) is referred to as slope, and the inclination of the workpiece in the perpendicular direction (X direction) is called rotation.

The improvement formed by the workpieces W1 and W2 is made into the shape of V (12 (a) degree) or Y (12 (b) degree) having an improvement angle of 30 to 65 degrees, as shown in FIG. Temporary pasting of the inner part of the improvement is applied temporarily so as not to cause an improvement deviation during welding. A backing material (BP) is placed on the back side of the improvement, and the granules or iron powder are dispersed in the improvement at a height not less than 1/4 but not more than 2/3, and 40 times with the preceding welding electrode wire wa1 (torch 30L). Fluctuations of 30 times / minute or more and 120 times / minute or less are applied to the post weld electrode wire wa2 (torch 30T). One unit of this fluctuation, or one time, is a one-round reciprocation.

A preceding welding electrode wire (wa1) of the welding current density of the wire end area 200A / mm ² or more, the trailing welding electrode wire (wa2) area 150A / mm ² or more the welding current density end wire of the prior (L-pole) and the following By conducting two-electrode single-side gas sealed arc welding with the inter-pole distance Dw of the welding current wires wa1 and wa2 of (T pole) 100 mm or more and 600 mm or less, the arc is stable, crack resistance, good surface, and bead At the same time, it is possible to weld with high efficiency. Moreover, the inter-pole distance Dw is the distance between the preceding welding electrode wire wa1 and the trailing welding electrode wire wa2 as shown in FIG.

Fig. 13 shows the relationship between the rigid scattering height and the shape of the backside beads in multi-electrode single-sided gas seal arc welding of several plate thicknesses. The welding agent conditions at that time are shown in Table 3. For the experiments, the current, swing width (oscillate width) and swing count (oscillate count; times / minute) were changed according to the thickness of each plate. Moreover, the "root gap" of Table 3 means the shortest distance between the counter facing workpieces W1 and W2 in an improved yellow cross section. The root gap is shown in FIG. 12 (b).

In addition, the circle symbol of FIG. 13 means good shape of the back side bead, the triangular symbol means bad shape of the back side bead, and the X symbol means that the back side bead shape or melting has occurred.

It can be seen from FIG. 13 that the rear bead shape is improved by spreading and welding the rigid granules within the improvement of the plate thickness to the height of 1/4 to 2/3 of the plate thickness. If the spread height exceeds 2/3 of the plate thickness, the back bead shape is bad or the back bead is not formed. In addition, melting occurred in 1/4.

Moreover, the grain size distribution of the granules or the iron powder is preferably 1.5 mm or less, since the stability of the arc and the shape of the back side beads are good. The component is mainly made of Fe, but considering the crack resistance, C is preferably 0.10% or less, and S and P are preferably 0.020% or less, and the other components are Si, Mn, and Mo in consideration of the toughness of the weld metal. It may also contain a deoxidizer or an alloying agent. The granular body which cut | disconnected steel wire of various size may be sufficient as the above particle size and a component are satisfied.

If the angle of improvement is less than 30 °, the uniformity of the backside bead is worsened, and if the angle of improvement is greater than 65 °, the improved cross-sectional area becomes large, so that the welding efficiency is lowered.

Temporary pasting of the improved inner surface reduces the gap variation during welding. In the case of using a ceramic solid backing material as the backing material (BP), if the backing material (BP) is supported on the surface of the welded material with a weak supporting force only by bonding the backing material (BP) to the back side of the welded portion. It is good and there is no need to use a magnet or restraining jig. Therefore, the effort is reduced. The same effect can be obtained as the backing material (BP) using either the copper backing material for glass tape bottles or the flux copper backing material besides the ceramic solid backing material.

Moreover, the temporary pasting of the inner surface of the refinery may be part of the weldment site wire or in part. In addition, the height of the temporary paste bead is preferably at least 2mm in order to complete the temporary paste at the same time less than 7mm in order to stabilize the back bead.

It is preferable that the root gap is 5 mm or less, and the root face (see Fig. 12 (b)) in the Y improvement is 3 mm or less because the ease of plate joint welding and the back side beads are stable. If the root gap exceeds 5 mm, the improved cross sectional area becomes wider, and thus the welding capacity decreases.

If the welding current density per wire cross-sectional area of the preceding welding electrode wire wa1 is less than 200 A / mm ² , stable backside beads cannot be obtained.

In particular, undissolved melt occurs at the temporary paste.

The amount of melt | dissolution generate | occur | produces when the welding current density per wire cross-sectional area of a post welding electrode wire wa2 is less than 150 A / mm <^2> .

In addition, the preceding welding electrode wire wa1 has obtained good results in any of the solid wires for mild steel, high tensile strength steel, and low temperature steel specified in JIS Z 3312 and Z 3325. It is preferable to use the solid steel for low temperature steel prescribed | regulated to JISZ3325.

In addition, the wire diameter has a high welding current density per wire cross-sectional area, and in order to improve the weldability and the shape of the back side bead, 1.4 mm or more and 2.0 mm or less in the leading electrode wire wa1 and 1.2 mm in the trailing electrode wire wa2. It is preferable that it is more than 2.0 mm.

The number of swings (times / minute) of the preceding electrode wire wa1 (torch 30L) is 40 times / minute or more and 150 times / minute or less in order to improve the shape of the backside bead. At less than 40 times / min, the bead waveform becomes rough and a good backside bead shape cannot be obtained. If it is more than 150 times / minute, the arc becomes unstable and a good backside bead shape cannot be obtained. The number of swings (times / minute) of the trailing electrode wire wa2 is 30 times / minute or more and 120 times / minute or less in order to improve the surface bead shape. At less than 30 times / min, the bead waveform becomes rough, and a good surface bead shape cannot be obtained. If it is more than 120 times / minute, the arc becomes unstable and a good surface bead shape cannot be obtained.

The electrode swing width (oscillate width) is changed stepwise according to the plate thickness for the purpose of improving the bead surface. It is preferable that the fluctuation width of the preceding electrode wire wa1 is 4 mm at the plate thickness of about 10 mm, and the fluctuation width of the trailing electrode wire wa2 is 6 mm. The fluctuation width of the preceding electrode wire wa1 is about 10 mm at the plate thickness of about 25 mm. It is preferable that the swing width of the trailing electrode wire wa2 is 15 mm.

The distance between the electrodes Dw (Fig. 8) between the preceding (L pole) and the trailing electrode (T pole) is less than 100 mm, and the arc becomes unstable, and at the same time, when the back side beads are excessively exceeded or exceeds 600 mm, toughness is effective. Even if the device is large, it is not preferable. In addition, the welding speed is determined by the plate thickness, but good welding is possible from 40 cm / min to 45 cm / min of plate thickness of 10 mm and 15 cm / min to 20 cm / min of plate thickness of 25 mm.

The same effect can be obtained when the fluctuations of the electrodes (wires wa1 and wa2) are parallel to the weld plate at the same time in the direction perpendicular to the weld line or parallel to the horizontal plane at the same time in the direction perpendicular to the weld line.

The wire entry angle γ (FIG. 2) with respect to the plate surface is obtained with good bead shape up to about 15 ° vertical or forward angle for both the leading and trailing electrodes.

Next, the fluxes used for the trailing electrode wire wa2 will explain the meaning of the components of the wire.

TiO ₂ : 2.5% or more and 7.0% or less:

TiO ₂ exhibits properties as a slug former and an arc stabilizer for weld beads, but a good surface bead shape cannot be obtained at less than 2.5% of the total weight of the wire. When the amount exceeds 7.0%, the amount of oxygen in the weld metal increases and large nonmetallic inclusions increase, so that the microstructure does not become fine and the toughness decreases. Therefore, the range is 2.5% or more and 7.0% or less.

ZrO ₂ : 0.4 or more and 1.0% or less:

ZrO ₂ increases the solidification rate of slag and slag coatability of molten metal and improves the appearance of beads. In addition, like TiO ₂ , the vapor pressure at high temperature is low, and it is effective in refining the volume, and the spatter is reduced. However, if the ratio is less than 0.4%, this effect cannot be obtained, and the appearance of surface beads becomes poor, and the amount of spatter generated increases. If it exceeds 1.0%, defects such as inhalation of slag tend to occur because the solidification temperature is high, so the range is set to 0.4 or more and 1.0% or less.

Al ₂ O ₃ : 0.1% or more and 1.0% or less:

Al ₂ O ₃ increases the solidification rate of slag such as ZrO ₂ and slag coatability of molten metal and improves the appearance of beads. However, this effect cannot be obtained at less than 0.1%. Moreover, when it exceeds 1.0%, defects, such as inhalation of slag generate | occur | produce, and since peelability of slag falls, the range was made into 0.1% or more and 1.0% or less.

Si: 0.2 or more and 1.2% or less:

Si acts as a deoxidizer and is effective in reducing the amount of oxygen in the weld metal. However, if it is less than 0.2%, the deoxidation power is insufficient and blowholes are generated. If it exceeds 1.2%, the ferrite is hardened to harden and the toughness is lowered, so the range is made 0.2 or more and 1.2% or less.

Mn: 1.0 or more and 4.0% or less:

Mn is effective in assisting deoxidation, increasing molten metal fluidity, improving bead shape, and improving strength toughness. However, if it is less than 1.0%, the carbonic acid is insufficient and weld bonds are easily generated. If the content is more than 4.0%, the weld metal is excessively deoxidized, and pits and blowholes are easily generated. The range is 1.0 to 4.0%.

Mg: 0.1 or more and 1.0% or less:

Mg reacts with oxygen in a high temperature arc, and deoxidation is performed in the stage of the volume of a wire tip. As a result, it is effective in that deoxidation products do not remain in the molten pool, moreover, assist in deoxidation of Si and Mn reacted in the molten pool, and improve the toughness by reducing the oxygen content of the weld metal. However, if it is less than 0.1%, the above effect is insufficient, and if it exceeds 1.0%, the arc length becomes excessive and the shape of beads becomes bad, so the range is made 0.1 or more and 1.0% or less.

Na, K: 0.003 or more and 0.3% or less in total of one kind or two kinds of Na, K:

Na, K has the effect of reducing the penetration of the base material by increasing the arc stability. However, at less than 0.03%, the above effect cannot be obtained. If the amount exceeds 0.3%, the arc length becomes too long and the amount of spatter amount of fumes increases.

When toughness is required at low temperatures, the fluxes further add Ni, Ti and B to the wire in the following ranges.

Ni: 0.3 or more and 3.0% or less:

Ni is added in order to secure strength and low temperature toughness. However, if less than 0.3%, sufficient toughness improvement effect cannot be obtained, and if it exceeds 3.0%, high temperature cracks are likely to occur, so that 0.3 or more is 3.0%.

Ti: 0.02 or more and 0.2% or less:

Ti is a strong deoxidizer and prevents oxidation of the weld metal, and at the same time, the microstructure of the weld metal is refined by the production of Ti oxide, which is effective in improving toughness. However, if it is less than 0.02%, the toughness improvement effect due to the microstructure of microstructure cannot be obtained, and if it exceeds 0.2%, carbides are remarkably formed and the toughness is impaired, so the range is set to 0.02 or more and 0.2% or less.

B: 0.002 or more and 0.015% or less:

B refines the microstructure of the weld metal and is effective in improving toughness. However, if it is less than 0.002%, the toughness improvement effect due to the microstructure of microstructure is not obtained, and if it exceeds 0.015%, the crack resistance deteriorates, carbides are formed and the toughness is impaired. Therefore, the range is 0.002 or more and 0.015% or less. It was.

In addition, in order to further improve the toughness by further improving the microstructure of the weld metal, Al may be added in the range of 0.30% or less and Zr: 0.20% or less. As the adjustment of the strength of the weld metal, Cr may be added 2.5% or less and Mo 2% or less.

In order to disperse stiffness or iron in the refinement, the preceding electrode wire wa1 uses a steel wire which is more soluble than the wires of the fluxes, but increases the current density per wire cross-sectional area and furthermore, the spatter of the spatters to swing the electrode wire. There is a lot of occurrence. Therefore, at least the preceding electrode wire wa1 is double-sealed in order to have a high shielding effect and reduce the amount of spatter generated.

According to the welding agent conditions shown in Table 4, the spatter generation amount was investigated especially in the preceding welding with a large amount of spatter generation.

The amount of spatter generated when the current was changed into three stages of 300A, 400A, and 500A and the conventional method (single shield) and the double shield was investigated. Usually, although the amount of spatters increases with increasing current in the conventional method, since it is about 2.0-5.0 g / min, the below was evaluated as favorable.

15 shows the relationship between the welding current and the spatter generation amount. When double-sealed, the amount of spatter generated was 2.0 g / min or less regardless of the change in current as compared with the conventional method (single-sealed).

The following Examples and Comparative Examples are described.

EXAMPLE

The steels shown in Table 5, the steel wires for the leading electrode wa1 shown in Table 6, and the fluxes for the trailing electrode wa2 shown in Table 7, combined with the wire, show the improved shapes shown in Tables 8 to 13 Two-sided single-sided gas-sealed arc welding with a welding length of 1500 mm was performed under the conditions of scattering, stiffening or iron powder, curved state and welding conditions. The welding speed was performed at 15 m / min or more and 450 m / min or less depending on the plate thickness.

In addition, the temporary sticking of the inner surface of the improvement was carried out in six places of 30 mm length at 300 mm intervals using a coated arc electrode.

After welding, surface, backside bead appearance, crack presence and impact value were investigated. The impact value was taken from the impact test piece of JIS Z2202 4 from the plate thickness center part of the test body after welding, and the impact value was measured at 0 degreeC.

In addition, the presence or absence of bacteria was examined in penetration test and macro section. These results are also collectively shown in Tables 8-13.

Furthermore, Tables 8 to 13 are one large table divided into six, and their tables are arranged as the following arrangement;

Table 8 Table 10 Table 12

Table 9 Table 11 Table 13

By arranging overlapping notations in neighboring tables and arranging them in the same plane, one large table appears.

No. in Tables 8-13 Examples of the welding method according to the present invention of 1 to 8, No. 9-28 are comparative examples. No. which is an embodiment of the present invention. 1 to 8 are double-shielded at least the preceding welding electrode wire wa1 with an appropriate shape, a scattering height of the grain or iron, the number of swings of the electrode, the welding current density, and the wire component of the trailing electrode wa2. Both the appearance of the back bead was good, and there was no bonding of high temperature cracks and the impact value was extremely good.

No. of Comparative Examples 9 had a narrow angle of improvement, so that the backside beads became nonuniform, and since Si and Mn of the trailing electrode wire wa2 (F5 in Table 7) were low, a blowhole occurred.

No. The 10 had a wider improvement, less swelling by welding, and excessive back beads. Furthermore, since the Si of the trailing electrode wire wa2 (F6) is high, the toughness is low, and the Mg is high, so that the appearance of the surface beads is uneven. No. 11 shows a low dispersion of the granules, resulting in melting of the molten metal. No. 12 had a high spread of granules, so there were no back beads. No. 13, since the Mn of the trailing electrode wire wa2 (F7) is high, a blowhole occurred. Moreover, since the total amount of Na and K was large, the amount of spatters generated was large.

No. Since the Mg of the trailing electrode wire wa2 (F8) is small, the toughness is low and the total amount of Na and K is small, and the arc becomes unstable.

No. 15 is a low welding current density of the preceding electrode wire (wa1) did not come out of the rear bead.

No. 16, the welding current density of the trailing electrode wire wa2 was low, resulting in poor appearance of the surface beads.

No. 17 has a low number of swings of the leading electrode wire wa1, so that the rear side beads are not aligned.

No. 18 shows poor surface bead appearance because the number of swings of the trailing electrode wire wa2 is small.

No. Since the number of swings of the leading electrode wire wa1 is high, the arc becomes unstable and the rear bead is not aligned.

No. Since the number of fluctuations of the trailing electrode wire wa2 is large, the arc becomes unstable and the surface bead is poor.

No. 21, the inter-pole distance Dw of the leading and trailing electrode wires wa1 and wa2 is small, resulting in an unstable arc and melting of the weld metal.

No. 22 had less TiO ₂ in the trailing electrode wire wa2 (F9), so that the appearance of the surface beads was poor.

No. 23 had low toughness because there were many TiO ₂ in the trailing electrode wire wa2 (F10).

No. Since the ZrO ₂ of the trailing electrode wire wa2 (F11) is small, the slag surface surface of the molten metal is poor, and the appearance of spatter is increased due to poor bead appearance.

No. 25 has a large amount of ZrO ₂ in the trailing electrode wire wa2 (F12), so that slag retreat occurs.

No. In the case of 26, Al ₂ O ₃ of the trailing electrode wire wa2 (F13) was low, so that the weld metal slad coatability was bad and the surface bead appearance was poor.

No. Since 27 has a lot of Al ₂ O ₃ of the trailing electrode wires wa2 (F14), defects in slag retreat occurred and at the same time, the slag peeling became poor.

No. Since 28 is not double-sealed, the amount of spatters increased.

Example 2

The low temperature steel materials shown in Table 14, the steel wires shown in Table 6, and the fluxes shown in Table 15 were combined with wires, and two-electrode one-side gas shielded arc welding as in Example 1 was performed. Furthermore, both tests double-sealed the leading and trailing electrode wires (wa1, wa2). In addition, evaluation of toughness investigated the impact value in -20 degreeC. These results are put together in Table 16, Table 17, and Table 18, and are shown. In addition, Tables 16 to 18 are obtained by dividing one large table into three tables, and these tables as the following arrangement;

Table 16 Table 17 Table 18

By arranging overlapping notations in neighboring tables and arranging them in the same plane, one large table appears.

No. in Tables 16-18 29 to 33 are examples of the welding method according to the present invention. 34-39 is a comparative example. No. which is an example of this invention 29 to 33 are suitable for the improved shape stiffness or distribution of iron, the number of swings of the electrode, the welding current density, and the filling flux component of the trailing electrode wire wa2 (F15 to F18: Table 15). Since the wires wa1 and wa2 were double-sealed, both the surface and the back bead appearance were satisfactory, without defects such as high temperature cracking and toughness.

No. of Comparative Examples 34 has low toughness because there is less Ni in the trailing electrode wire wa2 (F19).

No. 35 has a high Ni in the trailing electrode wire (wa2) (F20), so a high temperature crack occurred.

No. 36 has low toughness because there is little Ti in the trailing electrode wire wa2 (F21).

No. 37 had low toughness because many Ti of the trailing electrode wire wa2 (F22) were included.

No. 38 has low toughness because B of the trailing electrode wire wa2 (F23) is small.

No. 39 has low toughness because there are many B in the trailing electrode wire wa2 (F24).

As described above, according to the present invention, the one-sided welding of the long-shaped curved weld structure at short cutting is improved in weldability, crack resistance and back surface, and the surface bead is good, and a healthy and high toughness weld is obtained. It can be made small, and the one-line welding which does not require complicated operation during welding can greatly improve the plate joint work efficiency.

Claims (12)

An X traveling platform (Y1 Yz, RY, Y2) having an X traveling motor (M1) driven in accordance with an X current order, and traveling in the horizontal X direction; Y which is supported by the X traveling platform Y1, Yz, RY, and Y2 and is driven according to the current transfer order, and which travels in the horizontal Y direction perpendicular to the X direction with respect to the X traveling platform. Traveling table 4; A base 2 rotatably supported in the Y direction 4 in a vertical Z direction and rotatably supported about a vertical Z (0) axis; A Z lifting mechanism 12 which is driven according to a Z current order and includes a lifting motor M4 for driving the base 2 in a vertical Z direction; a slewing mechanism (10) including a first rotating motor (M3) driven in accordance with θ current order to rotate and drive the base (2) about a vertical Z (0) axis; First detection means (P3) supported by said base (2) for detecting the Z position of the improvement (b) on the extension line of the rotation center axis (0) and the position in the direction perpendicular to the Z direction; Second detecting means (P2) supported by the base (2) and detecting a Z position and a position perpendicular to the Z direction of the improvement (b) of a position away from the rotation center axis (0) by a predetermined distance; And a welding torch (30L, 30T) for welding the improvement (b) supported on the base (2). The inclination to the horizontal plane of the bend θ 'of the improvement (b) in the direction crossing the direction in which the improvement (b) of the welded material (W1, W2) extends and the direction in which the improvement (b) extends. α is calculated from the detection values of the first and second detection means P3 and P2, and the base 2 is pivotally driven through the θ turning mechanism 10 in response to the bending θ 'to correspond to the tilt α. And a control means (8) for elevating and driving the base (2) through a Z elevating mechanism (12). The torch support frame (3) according to claim 1, further comprising: a torch support frame (3) rotatably supported on the base (2) about a horizontal X axis to support welding torches (30L, 30T); And a γ rotating mechanism including a second rotating motor (M7) for rotationally driving the torch support frame (3) about the horizontal axis (31a) according to the γ current order. . The inclination to the horizontal plane of the bend θ 'of the improvement (b) in the direction transverse to the direction in which the improvement (b) of the welded materials W1 and W2 extends and the direction in which the improvement (b) extends. α is calculated from the detection values of the first and second detection means P3 and P2, and the base 2 is pivotally driven through the θ turning mechanism 10 in response to the bending θ ', corresponding to the inclination α. And control means (8) for elevating and driving the base (2) through a Z elevating mechanism (12), and rotating the torch support frame (3) through a γ rotating mechanism (M7) corresponding to the inclination (alpha). The one-side welding device of the curved sheet, characterized in that. 4. The torch support frame (3) according to claim 3, wherein: the torch support frame (3) folds the welding torches (30L, 30T) against the welded materials (W1, W2); The apparatus further comprises a torch upper and lower gear including torch upper and lower motors (M8, M10) for driving the welding torch (30L, 30T) in response to the folding battery order. The bending θ 'of the improvement (b) in the direction crossing the direction in which the improvement (b) of the welded material (W1, W2) extends, and the horizontal plane of the direction in which the improvement (b) extends. The inclination α is calculated from the detected values of the first and second detection means P3 and P2, and the base 2 is pivotally driven through the turning mechanism 10 in response to the bend θ ', thereby turning on the inclination α. Correspondingly, the control means 8 for elevating and driving the base 2 through the Z elevating mechanism 12 and for fold-drive the welding torches 30L and 30T through the torch upper and lower openings M8 and M10 in response to the inclination α. One side welding apparatus of the curved sheet further comprising a. The torch support frame (3) according to claim 3, wherein the torch support frame (3) has welding torch (30L, 30T) in the direction orthogonal to the vertical line connecting the first and second detection means (P3) and (P2). Reciprocatingly movable against W2, the apparatus is also supported by the base 2 and is relatively spaced in a direction orthogonal to the longitudinal line, the first welded material each of which constitutes the improvement (b) ( W1) and third detection means P5 and fourth detection means P4 for detecting the Z position of the surface of the second to-be-welded material W2; And an oscillate mechanism including oscillate motors (M9, M11) for reciprocating the welding torches (30L, 30T) in accordance with the oscillation conduction order. The inclination to the horizontal plane of the bend θ 'of the improvement (b) in the direction crossing the direction in which the improvement (b) of the welded materials W1 and W2 extends and the direction in which the improvement (b) extends. α is calculated from the detection values of the first and second detection means P3 and P2, and the base 2 is pivotally driven through the θ turning mechanism 10 in response to the bending θ ', corresponding to the inclination α. The base 2 is moved up and down through the Z elevating mechanism 12, and the inclination β with respect to the horizontal plane of the to-be-welded materials W1 and W2 in the direction orthogonal to the direction in which the improvement b extends is third and third. 4 Control means for calculating from the detection values of the detection means P5 and P4 and deviating the amplitude center of the oscillate reciprocating drive of the welding torches 30L and 30T by the oscillate mechanisms M9 and M11 corresponding to the inclination β. (8); The one-sided welding device of the curved sheet further comprising. X traveling platform (Y1, Yz, RY, Y2) traveling in the horizontal X direction, Y traveling platform supported by the X traveling platform (Y1, Yz, RY, Y2) and performing in the horizontal Y direction perpendicular to the X direction ( 4) a base (2) capable of lifting up and down in the vertical Z direction and rotatably supported about the vertical Z axis (0), and lifting and driving this base (2) in the vertical Z direction. Z elevating mechanism (12), θ turning mechanism (10) for rotating the base (2) about a vertical Z axis (0), supported by the base (2) on the extension line of the rotation center axis (0) The first detecting means P3 for detecting the Z position of the improvement (b) and the position in the direction perpendicular to the Z direction, the improvement of the position supported by the base 2 and spaced apart from the rotation center axis 0 by a predetermined distance ( 2nd detection means P2 which detects the Z position of b) and the position of a direction perpendicular | vertical to a Z direction, and a pair of gas shielded arc welding supported by the said base 2, and welding the said improvement (b). Torch (30L, 30T) In the mimic welding of the improvement (b) between the curved to-be-welded materials W1 and W2 with the pair of welding torches 30L and 30T by using a single-sided welding device, the curved to-be-welded material W1 is used. , W2), the improvement angle of the improvement (b) of the V or Y shape which temporarily attached the inner surface was set to 30-65 degrees, and the back surface of the improvement (b) was used as a backing material, and it solidified within this improvement (b). Alternatively, iron is filled to a height of 1/4 or more and 2/3 or less of the thickness of the plate to be welded (W1, W2), and the electrode wires (wa1, wa2) of the pair of gas shielded arc welding torches 30L and 30T. ) 150A / mm for the welding current density of the electrode wire (wa2) that is the gap distance in a range from 100mm 600mm, prior to welding to the trailing welding current density of the electrode wire (wa1) 200A / mm ² or more, at the same time that the equal to or greater than ² and, at the same time, the electrode wire (wa1) of a preceding 40 times / minute over 150 times / min or less, fluctuations of the trailing electrode wire (wa2) of less than 30 times / minute over 120 times / min. A one-sided welding method for a curved sheet characterized in that the drive. 10. The method according to claim 9, wherein the trailing electrode wire wa2 is present in terms of weight percent of TiO ₂ : 2.5% or more and 7.0% or less ZrO ₂ : 0.4% or more and 1.0% or less Al ₂ O ₃ : 0.1% or more and 1.0% Si: 0.2% or more and 1.2% or less Mn: 1.0% or more and 4.0% or less Mg: 0.1% or more and 1.0% or less, and furthermore, a flux containing one or two kinds of Na and K in a total of 0.03% or more and 0.3% or less The one-side welding method of the curved sheet, characterized in that the charged flux is a wire. 12. The flux according to claim 10, wherein the subsequent electrode wire wa2 further contains, in weight percent, Ni: 0.3% or more and 3.0% or less Ti: 0.02% or more and 0.2 or less B: 0.002% or more and 0.015% or less The one side welding method of the curved sheet, characterized in that the flux is filled with a wire. 10. The method according to claim 9, wherein at least the preceding electrode wire wa1 is double shielded with a first shield gas and a second shield gas.

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