JP2761718B2 - Automatic copying apparatus for inner surface welding torch and method for manufacturing welded steel pipe in manufacturing welded steel pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic copying apparatus for an inner surface welding torch and a welded steel pipe for manufacturing a welded steel pipe in which a strip-shaped metal plate is formed into a cylindrical shape, and a welded portion of the metal plate is welded at abutting surfaces of both end surfaces. And a method for producing the same.

[0002]

2. Description of the Related Art As a method of manufacturing a welded steel pipe, there is a method in which a strip-shaped metal plate is formed into a cylindrical shape, and a welded portion at an abutted end is simultaneously welded with a downward plasma and a TIG arc and an upward TIG arc. is there. The upward TI
G inner surface welding torch is plasma and TI of downward torch.
There is a case where the unwelded portion of the welded portion butted by the G arc is welded, and a case where the inner bead generated by the downward welding is melted by the TIG arc and smoothed.

[0003] The schematic structure of a conventional welding steel pipe manufacturing apparatus will be briefly described with reference to Fig. 1 showing the present invention. The plasma and the plasma are directed downward above the abutting surface of a pipe 1 formed from a strip-shaped metal plate into a cylindrical shape. An external torch 10 for generating a TIG arc is provided. In addition, this outer surface torch 10
An inner torch 32 for generating an upward TIG arc is disposed inside the pipe 1 at the rear. The inner surface torch 32 is fixed to the distal end of a support arm (31 in the present invention, which is different from the conventional structure, but is not numbered) inserted from a crack in the pipe 1, and has an outer surface. The operator manually operates the support arm so as to follow the position of the outer surface torch 10 according to the welding position of the torch 10.

FIG. 11 shows a state in which the inner bead 70 formed by welding with the outer torch 10 is melted and smoothed by the inner torch 32 using an upwardly directed TIG arc. . This inner torch 32
The inner bead 70 is melted and smoothed by the upward TIG arc as shown in FIG. 12 so as to meet a predetermined standard.

[0005]

In such a conventional apparatus and method for manufacturing a welded steel pipe, the inner surface torch 32 is installed in a pipe (steel pipe) 1 which has already been formed into a cylindrical shape and is welded downward by the outer surface torch 10. Therefore, the state of the tip of the inner surface torch 32 cannot be seen from the appearance. Therefore, in the vertical and horizontal adjustments of the inner torch 32, the operator has to set the position with a sense while visually observing the state of the surface of the pipe 1 heated by the arc heat. As a result, there is a problem in that the welding quality varies due to the skill of the operator, a welding defect occurs, and the inner surface bead 70 is not smooth as required quality (height and width).

If the inner torch 32 does not have a function to follow the inner bead 70, if the relative relationship between the position of the inner bead 70 and the position of the inner torch 32 is deviated during welding due to distortion of the pipe 1, etc. Unsatisfactory welding occurs continuously until the operator notices. This is particularly noticeable when the relative position between the inner bead 70 and the inner torch 32 is displaced and there is no function of detecting the displacement and issuing an alarm. In the case where the alarm function is provided, even if it is a manual operation, the operator notices immediately, so that it is possible to reduce the number of defective welding.

If the pipe 1 fluctuates in the circumferential direction for some reason, it is necessary to manually adjust the tip of the outer torch 10 to the position of the abutting surface, but every time the position of the outer torch 10 is adjusted, In order to match the position of the outer torch 10, the inner torch 32 must be manually adjusted left and right. That is, the position of the inner bead 70 formed by the outer torch 10 and the position of the inner torch 32 are shifted in the left-right direction. This inner torch 3
Since the adjustment of No. 2 is manual and cannot be visually recognized from the outside as described above, there has been a problem that it is very difficult to accurately adjust the position of the inner surface torch 32.

Furthermore, the consumption of the electrode (tungsten electrode) 33 at the tip of the inner surface torch 32 changes the amount of heat input to the inner surface bead 70, changing the bead shape. In the past, this change could not be quantitatively grasped and the distance between the inner bead 70 and the electrode 33 could not be kept constant, so that the inner bead 70 could not be smoothed and the required welding quality could be satisfied. Did not.

[0009] The present invention has been made in view of the above-mentioned point, and the position of the inner torch with respect to the outer torch is always automatically made to follow the same line, thereby eliminating the need for an operator's intuition. In addition, the distance between the inner surface of the workpiece and the electrode at the tip of the inner torch is automatically corrected to be constant, and an automatic copying of the inner welding torch in the production of a welded steel pipe in which a smooth inner bead can be obtained. An apparatus and a method for manufacturing a welded steel pipe are provided.

[0010]

According to the present invention, there is provided an automatic copying apparatus for an inner surface welding torch for manufacturing a welded steel pipe according to the first aspect of the present invention. And an outer torch 10 for welding the portion to be welded. The outer torch 10 is disposed behind the outer torch 10 in the feeding direction of the workpiece 1 and below the butt surface of the workpiece 1, and is welded by the outer torch 10. Inner bead 7 formed on the lower surface side of
0, an inner torch 32 that melts the inner surface of the workpiece 1, a support arm 31 that is disposed on the distal end side of the inner torch 32, and is disposed below the workpiece 1; and a first driving unit that moves the support arm 31 in the left-right direction. 49, first detecting means 15 for detecting a positional shift of the outer surface torch 10 in the left-right direction orthogonal to the feeding direction of the workpiece 1, and the outer surface torch 10
The second drive means 37 for detecting the displacement of the inner surface torch 32 with respect to the position of the first drive means, and the first drive means 49 is driven by the position detection signals from the first and second detection means 15 and 37. Control means 2 for setting the position of the inner surface torch 32 on the same line in the horizontal direction of the outer surface torch 10
1 is provided.

Here, the first drive means 49 rotates the output shaft 51 of the servomotor 50 to move the drive shaft 52 screwed with the output shaft 51 in the axial direction, thereby causing the support arm 31 to rotate. Are moved in the left-right direction. Further, the first detecting means 15 is constituted by an electric measure 15 for detecting an amount of movement when the outer surface torch 10 moves in the left-right direction which is a direction orthogonal to the abutting surface of the pipe 1. Further, the second detection means 37 is constituted by a visual camera 37, and performs image analysis processing by the image analysis device 40 with the center of the surface glow portion 34 formed by the inner torch 32 as the center of the inner torch 32. Thus, the position of the inner torch 32 with respect to the outer torch 10 is detected. Further, the control means 21 is constituted by a device control panel 21 composed of a computer, and receives signals from the electric measure 15 and the image analysis device 40 so that the inner torch 32 is automatically aligned with the outer torch 10. Then, the servo motor 50 of the X-axis movement guide unit 49 is driven.

Further, in the automatic copying apparatus for the inner surface welding torch in the manufacture of the welded steel pipe according to the second aspect, the outer surface torch 10 is disposed above the butt surface of the workpiece 1 to be fed out and welds the butt surface portion. The outer surface torch 10 is disposed rearward of the workpiece 1 in the feeding direction of the workpiece 1 and below the butt surface of the workpiece 1, and is formed on the lower surface side of a portion welded by the external torch 10. Inner surface torch 32 for melting inner surface bead 70
And the inner surface torch 32 is disposed on the distal end side.
, A second driving means 60 for moving the support arm 31 in the vertical direction, and detecting a surface temperature of the surface glowing portion 34 formed by being heated by the inner surface torch 32. The third detecting means 43 receives the temperature detection signal from the third detecting means 43, converts the received heat amount into a heat input amount at the welding target portion, and controls the second driving means 60 so that the heat input amount becomes a preset heat input amount. Drive to inner torch 32
And a control means 21 for keeping the distance L between the electrode 33 at the tip of the workpiece and the lower surface of the workpiece 1 constant.

Here, the third detecting means 43 comprises a non-contact type surface temperature sensor 43, and detects the surface temperature of the surface glowing portion 34 formed by heating the inner surface torch 32. . The second drive means 60 rotates the output shaft 63 of the servomotor 62 to move the drive shaft 64 screwed with the output shaft 63 in the axial direction, and moves the support arm 31 in the vertical direction. It comprises a Z-axis movement guide unit 60 to be moved. This surface glow 3
The Z-axis moving guide unit 60 is driven so that the heat input amount at the welded portion is always constant by the detected temperature of 4 so that the distance L between the electrode 33 of the inner surface torch 32 and the inner surface of the pipe 1 is constant. ing.

Further, in the automatic copying apparatus for the inner surface welding torch according to the third aspect of the present invention, the outer surface torch 10 is disposed above the butt surface of the workpiece 1 to be fed out and welds the butt surface portion. The outer surface torch 10 is disposed rearward of the workpiece 1 in the feeding direction of the workpiece 1 and below the butt surface of the workpiece 1, and is formed on the lower surface side of a portion welded by the external torch 10. Inner surface torch 3 for melting inner surface bead 70
2, a support arm 31 disposed below the workpiece 1 with the inner surface torch 32 disposed on the distal end side, and first driving means 49 for moving the support arm 31 in the left-right direction.
The first driving means 49 is linked with the first driving means 49 so as to drive the support arm 31 only in the left-right direction, and the second driving means 60 for moving the support arm 31 only in the vertical direction. First detecting means 15 for detecting a positional deviation in the left-right direction orthogonal to the feed-out direction of the workpiece 1
And the inner torch 32 with respect to the position of the outer torch 10
A second detecting means 37 for detecting a displacement of the surface, and a surface glowing portion 34 formed by heating by the inner surface torch 32.
Third detecting means 43 for detecting the surface temperature of the
The first drive means 49 is driven by the position detection signals from the detection means 15 and the second detection means 37 to set the position of the inner torch 32 on the same line in the left-right direction of the outer torch 10, and Receiving the temperature detection signal from the detecting means 43, and converting it into the heat input amount of the welded portion, and driving the second drive means 60 so that the heat input amount becomes a preset heat input amount, thereby forming the electrode 33 at the tip of the inner surface torch 32. And workpiece 1
And a control means 21 for keeping a distance L from the lower surface of the device constant.

An automatic copying apparatus for an inner welding torch in the manufacture of a welded steel pipe according to a fourth aspect is provided with an alarm device 28 for issuing an alarm when the set value of the inner torch 32 exceeds an allowable value. And

Further, in the automatic copying apparatus for the inner surface welding torch in the manufacture of the welded steel pipe according to the fifth aspect, the outer surface torch 10
Is characterized in that the position in the left-right direction is stored as data and numerically displayed.

Further, in the method for manufacturing a welded steel pipe according to the present invention, an outer torch 10 is disposed above a butt surface of the workpiece 1 to be fed and welds the butt surface portion. The inner bead 70 is disposed rearward of the workpiece 1 in the feeding direction and below the abutting surface of the workpiece 1 and is formed on the lower surface side of a portion welded by the outer torch 10 to melt the inner bead 70. An inner surface torch 32, a support arm 31 that is disposed on the distal end side of the inner surface torch 32 and is disposed below the workpiece 1, a first driving unit 49 that moves the support arm 31 in the left-right direction, The first driving means 49 is interlocked to drive the support arm 31 only in the left-right direction, and the second driving means 60 for moving the support arm 31 only in the vertical direction. The workpieces to be joined of the outer surface torch 10 1
A first detecting means 15 for detecting a positional shift in the left-right direction orthogonal to the feeding direction of the inner torch; a second detecting means 37 for detecting a positional shift of the inner torch 32 with respect to the position of the outer torch 10; A third detecting means 43 for detecting the surface temperature of the surface glowing portion 34 formed by the heating, and the first driving based on position detection signals from the first detecting means 15 and the second detecting means 37. Means 49
To set the inner surface torch 32 on the same line in the left-right direction of the outer surface torch 10, receive the temperature detection signal from the third detecting means 43, convert it to the heat input amount of the welded part, and set it in advance. Control means 21 for driving the second drive means 60 so that the heat input amount becomes constant, and keeping the distance L between the electrode 33 at the tip of the inner surface torch 32 and the lower surface of the workpiece 1 constant. 10 to be welded 1
When the welded portion comes to the position of the inner surface torch 32, the control means 21 and the first drive means 4
9, the position of the inner surface torch 32 in the left-right direction is set, welding is performed by the inner surface torch 32, the temperature of the surface glowing portion 34 being welded is detected by the third detecting means 43, and the heat input amount of the welded portion is detected. Is controlled by the control means 21 to provide feedback to the second drive means 60 so as to control the position of the inner surface torch 32 in the vertical direction.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic system configuration diagram of an automatic copying apparatus for an inner surface welding torch in manufacturing a welded steel pipe according to the present invention, and FIG. 2 is an enlarged perspective view of a main part. In this apparatus, a flat steel plate is sequentially sent out while being shaped into a cylindrical pipe, and both end portions of the steel plate, which are butt surfaces of the pipes, are continuously welded.

1 and 2, the pipe 1 is fed in the direction of a white arrow in the figure, and a pair of guide squeeze rolls 2, 3, 4, 4 are provided on both sides of the pipe 1.
5, 6, and 7 are rotatably arranged at predetermined intervals. An outer torch 10 called a preceding welding torch is disposed above the butt surface of the pipe 1, and the outer torch 10 is mounted on the outer torch operating section 9.
A feed screw 12 rotatably driven by a manual handle 11 is rotatably supported on the outer surface torch operating section 9, and a support 13 is screwed to the feed screw 12 so as to be able to advance freely. The support 13 is movable in the axial direction of the feed screw 12 by rotating the manual handle 11 clockwise or counterclockwise inside the outer surface torch operating section 9.

A flat support arm 14 fixed to the support 13 is provided outside the outer surface torch operating section 9. The outer surface torch 10 is attached to the tip of the support arm 14. ing. The outer surface torch operating section 9 is set so that the electrode at the tip of the outer surface torch 10 is located above the abutting surface of the pipe 1. By rotating the manual handle 11, the outer surface torch 10 is Can be moved in the left-right direction of the pipe 1, that is, in the direction orthogonal to the direction of the butting surface of the pipe 1, and by operating the manual handle 11, the electrode of the outer surface torch 10 is positioned above the butting surface of the pipe 1. ing.

An electric measure 15 such as a potentiometer for detecting the moving distance of the support arm 14, that is, the moving distance of the outer torch 10 in the left-right direction is disposed above the outer torch operating section 9. The signal detected by the electric measure 15 is input to the electric measure controller 17 via the cable 16. In the electric measure controller 17, a signal from the electric measure 15 is converted into a digital signal as position data of the outer surface torch 10, and the converted digital signal is input via a cable 18 to a device control panel 21 as a central control device. It has become so.

A substantially L-shaped support arm 31, which will be described later, is inserted into the pipe 1 through a crack on the delivery side of the pipe 1 and is provided at the tip of the support arm 31 behind the position of the external torch 10. Is disposed toward the upper inside of the pipe 1. The electrode (for example, tungsten electrode) 33 at the tip of the inner surface torch 32 is located at a predetermined distance from the welded portion of the butt surface of the pipe 1 as shown in FIGS. The function of the inner surface torch 32 is that the inner surface bead 70 of the pipe 1 (FIG. 1)
1) is melted and smoothed. Then, when welding is performed to smooth the inner bead 70 formed inside the pipe 1, a surface glowing portion 34 as shown by a hatched portion in FIG. 2 is generated on the surface of the pipe 1.

The surface glow 3 generated on the surface of the pipe 1
4 is arranged above the pipe 1, and the center position of the surface glow portion 34 imaged by the visual camera 37 is set as the position of the inner torch 32, and the inner torch 32 is positioned at the position of the outer torch 10. This is corrected so as to be concentric (the abutting surface of the pipe 1, that is, on the same line as the portion to be welded). A signal from the visual camera 37 is input via a cable 38 to an image analyzer 40 having a display device 39. That is, the welded portion (surface red hot portion 34) heated by the inner surface torch 32 and changed to red is captured as data in the image analyzer 40 by the visual camera 37, and the center of the heated portion is obtained by arithmetic processing. Assuming the center of the inner torch 32, the position of the outer torch 10 to be pre-welded is set as a reference (the position of the inner bead 70), and the center of the heating unit (the surface glowing part 34) (the position of the inner torch 32) is used as a reference.
The following control is performed. Further, the position data of the surface glow portion 34 processed by the image analysis device 40 is sent to the device control panel 21 via the cable 41.

Further, a non-contact type surface temperature sensor 43 for detecting the temperature of the surface glow portion 34 is disposed above the pipe 1, and the surface temperature sensor 43 receives radiant energy from the surface glow portion 34. The surface glowing part 34
Is to detect the temperature. That is, the surface temperature sensor 43 detects the surface temperature of the surface red-hot portion 34 to control the amount of heat input to the molten portion of the inner bead by the inner surface torch 32. By controlling the amount of heat input, the pipe 1 The distance between the inner surface and the electrode 33 of the inner surface torch 32 is set to an optimum value. A signal from the surface temperature sensor 43 is input to a temperature sensor controller 45 via a cable 44, and the temperature sensor controller 45 converts the measured temperature of the surface red hot section 34 into a voltage value. Then, the voltage value obtained by converting the measured temperature is sent to the device control panel 21 via the cable 41 as data.

Next, a structure for controlling the movement of the inner surface torch 32 in the horizontal direction and the vertical direction will be described. The horizontal and vertical directions of the inner torch 32, that is, the horizontal and vertical movements of the support arm 31 provided with the inner torch 32 at the tip are performed by signals from the device control panel 21. X-axis movement guide unit 49 for moving inner surface torch 32 in the left-right direction (X-axis direction)
And a Z-axis movement guide unit 60 for moving the inner surface torch 32 in the vertical direction (Z-axis direction).

That is, as shown in FIG. 1, a servomotor 50 for driving the support arm 31 in the left-right direction (X-axis direction) is provided on the end surface side of the X-axis movement guide unit 49 having an opening surface on one side. This servo motor 5
0 is connected to the device control panel 21 by a cable 48. Here, the X-axis movement guide unit 49 itself is fixed to the base frame of the present apparatus and does not move. X
The output shaft 51 of the servo motor 50 fixed to the end face side of the axis movement guide unit 49 projects into the X axis movement guide unit 49 and extends along the longitudinal direction of the X axis movement guide unit 49 as shown in FIG. It is arranged. A screw is threaded on the outer peripheral surface of the output shaft 51, and a drive shaft 52 connected and fixed to the Z-axis movement guide unit 60 side is screwed to the output shaft 51 so as to be capable of screwing. That is,
The drive shaft 52 is formed with a screw hole screwed with the output shaft 51. Although the connection structure of the two units 49 and 60 is slightly different between the structure shown in FIG. 3 and the structure shown in FIG. 1, FIG. 3 illustrates the connection structure for easy understanding. Is the same.

A plate 61 is integrally fixed to the side surface of the Z-axis movement guide unit 60. The plate 61 and the substrate 53 of the drive shaft 52 are overlapped and connected and fixed by bolts 54. I have. A servo motor 62 is provided on the upper surface of the Z-axis movement guide unit 60, and an output shaft 63 of the servo motor 62 is provided so as to protrude along the longitudinal direction of the Z-axis movement guide unit 60. A screw is also threaded on the outer peripheral surface of the output shaft 63, and a drive shaft 64 similar to the drive shaft 52 is screwed so as to be able to freely advance. The servomotor 62 is connected to the device control panel 21 via a cable 58. At the base of the support arm 31 provided with the inner surface torch 32 at the tip, a plate-shaped connecting body 35 is integrally erected, and a substrate 65 of the drive shaft 64 is fixed to a side surface of the connecting body 35. Have been.

Here, when the servo motor 50 is driven by a signal from the device control panel 21, the output shaft 51 rotates. Since the X-axis movement guide unit 49 itself is fixed to the base frame by the rotation of the output shaft 51, the drive shaft 52 screwed with the output shaft 51 moves in the left-right direction as shown by the arrow in FIG. Will be. When the drive shaft 52 moves in the left-right direction, the drive shaft 52 and the Z-axis movement guide unit 60 are connected and fixed via the plate 61, so that the Z-axis movement guide unit 60 itself moves in the left-right direction. The movement of the Z-axis movement guide unit 60 in the left-right direction causes the support arm 31 to move in the left-right direction, whereby the inner surface torch 32 moves in the left-right direction.

Next, when the servo motor 62 is driven by a signal from the device control panel 21, its output shaft 63 rotates. When the output shaft 63 rotates, the drive shaft 64 screwed to the output shaft 63 moves in the axial direction of the output shaft 63.
That is, the drive shaft 64 moves vertically.
As a result, the support arm 31 connected and fixed to the drive shaft 64 via the connector 35 moves in the vertical direction. Therefore, when the servo motor 62 is driven, the inner surface torch 32 moves up and down.

[0030] Figure 4 shows a block diagram of the whole, including the inside of the equipment control panel 21, equipment control panel 21 comprising a microcomputer, the position data alpha ₁ of the outer surface torch 10 from electrical major controller 17 and image analysis Device 40
And a comparison unit 23 for comparing and judging the position data α ₂ of the inner surface torch 32 with the reference value β of the preset reference voltage.
₁ and a voltage-converted measurement value β ₂ from the temperature sensor controller 45 and a correction value obtained by adding a correction value obtained by converting the welding current of the inner surface torch 32 to an arc length, and making a comparison judgment.
And a motor drive unit 25 for controlling the servomotor 50 for controlling the movement of the support arm 31, that is, the inner surface torch 32 in the left and right direction, to the normal rotation and the reverse rotation, and a servomotor 62 for controlling the movement of the inner surface torch 32 in the vertical direction. , A motor drive unit 26 for controlling the drive in the reverse direction, a memory 27 for storing a control program for the apparatus and various data, and a display element or sound (buzzer) when the set value of the inner surface torch 32 is exceeded. It comprises an alarm device 28 for issuing an alarm to an operator, and a CPU 22 for controlling the whole.

Next, the inner torch 32 follows the welded portion by the outer torch 10 and the electrode 33 of the inner torch 32
The operation of automatically correcting the distance between the front end and the inner bead 70 will be described. First, the feed screw 12 is rotated by the manual handle 11 to move the support 13 in the left-right direction, so that the tip of the electrode of the outer torch 10 and the portion of the butting surface of the pipe 1 correspond to each other to position the outer torch 10. Do. At this time, the inner torch 32 located in the pipe 1 behind the outer torch 10 is positioned below the abutting surface of the pipe 1 in conjunction with the left-right movement of the outer torch 10, and at the same time, The material and size of the torch 32 to be welded to the inner surface of the pipe 1
Positioning is automatically and uniquely determined from the relationship of thickness and the like. Then, the butt surfaces of the pipes 1 sent out by the outer surface torch 10 are continuously welded.

When welded by the outer surface torch 10, an inner surface bead is formed on the inner surface of the pipe 1 at the welded portion.
The inner bead is melted by welding the inner torch 32 to smooth the inner surface of the pipe 1. Here, an initial setting position of the outer surface torch 10 before welding of the inner surface torch 32 is detected in advance by the electric measure 15 and the electric measure controller 17 and, as shown in FIG. Let it be the origin P. While the pipe 1 is being fed, the mating surface of the pipe 1 is
, The manual handle 11 is manually rotated to align the outer surface torch 10 with the center of welding of the butt surface of the pipe 1. Moving the manual handle 11 of the outer surface torch 10 in the left-right direction, it detects the amount of movement by the electric measure 15, by an electric measure controller 17 calculates a movement amount as position data alpha ₁ that has been digitized, such as digital data. That is, the position data α ₁ is a value of a difference from the absolute original position (the origin P). The position data α ₁ is input to the comparison / determination unit 23 of the device control panel 21 as shown in FIG.

On the other hand, the position of the inner torch 32 is detected by the visual camera 37. When welding is performed by the inner torch 32 so as to smooth the inner bead in the pipe 1, the surface of the pipe 1 is heated by the welding to generate red heat. A substantially elliptical surface glow portion 34 is formed as shown in FIG. The surface glowing portion 34 is imaged by the visual camera 37 and sent to the image analysis device 40 to display the surface glowing portion 34 on the screen of the display device 39 as shown in FIG.
4a. It is adapted to be processed by the image analysis device 40 as the center of the screen of the display device 39 always corresponds to the position data alpha ₁ of the outer surface torch 10. Since the visual camera 37 is fixed at a fixed position, the external torch 10 manually moved in the left-right direction is used.
In contrast, the inner torch 32 is shifted in the left-right direction. Therefore, when the display on the screen of the display device 39 by imaging the surface red-heated section 34 which visual camera 37 is shifted to the left or right, red-heated section image 34a as shown in FIG. 8 to be deviated from the position data alpha ₁ Become. Then, the position data α ₂ is the center position of the surface glow part 34 obtained by analyzing the glow part image 34 a of the welded part surface extracted by the visual camera 37 by the image analyzer 40, that is, the inner surface torch 32.
, Such as digitized digital data as the position of.

In FIG. 5, the position data α ₁ of the outer surface torch 10 is calculated by the electric measure controller 17 or the like in step S _1, and the position data α ₂ of the inner surface torch 32 is calculated by the image analyzer 40 in step S 2. . These position data α ₁ and α ₂ are input to the comparison determination unit 23 shown in FIG. 4, and the position data α ₁ and α ₂ are compared as shown in step S3. Position data alpha ₁ and alpha ₂ and the results of comparison in step S3, if α ₁ = α _2,
It is determined that there is no misalignment between the outer torch 10 and the inner torch 32 in the left-right direction, and the process proceeds to step S4. Therefore, in step S4, since the inner torch 32 and the outer torch 10 are concentric, the movement of the inner torch 32 in the left-right direction is not controlled, and the servomotor 50 is not driven.

Next, in step S3, the position data α ₁ and α
Results of the comparison between the _2, if alpha ₁ <alpha ₂ step S5
Then, it is determined that the position of the inner surface torch 32 is shifted to the right side, for example, and control is performed to correct the position of the inner surface torch 32 in the leftward feed direction. Then, in step S6, the motor drive unit 25 drives the servo motor 50 in the reverse direction to move the inner torch 32 to the left, and controls the movement of the inner torch 32 so that α ₁ = α ₂ .

Further, in step S3, the result of the comparison between the position data alpha ₁ and alpha _2, if α _1> α _2, the process proceeds to step S7, determines that shift to the left for example, the position of the inner surface torch 32 Then, control is performed to correct the position of the inner surface torch 32 in the rightward feed direction. Then, in step S8, the motor driving unit 25 drives the servo motor 50 to rotate in the normal direction to move the inner surface torch 32 rightward, so that α ₁ =
the alpha ₂ describes the desired movement control of the inner surface torch 32.
In this manner, the above operation is repeated to control the inner torch 32 so as to eliminate the lateral displacement of the inner torch 32 with respect to the outer torch 10.

The left and right positions of the outer torch 10 to be pre-welded are detected and stored as data in the memory 27 or the like. When the welding position reaches the position where the inner torch 32 is to be welded, the above-mentioned position of the inner torch 32 is determined. The calculations are linked so that the left and right positions are determined by the movement control. The positions of the outer surface torch 10 and the inner surface torch 32 are stored in the memory 27 and numerically displayed on a display unit (not shown) to facilitate reproducibility. In particular, outer torch 1
0 is manually operated, so any sudden failure,
For example, the position of the outer surface torch 10 is displaced by an artificial obstacle in which the operator unexpectedly moves the manual handle 11 or a surrounding obstacle in which the manual handle 11 is moved by interfering with a peripheral device by a crane or the like. Is stored, the position of the outer surface torch 10 is stored, so that the reproducibility of easily returning the outer surface torch 10 to the original position is facilitated.

Here, the inner torch 32 is connected to the outer torch 10.
When the servomotor 50 is driven to follow the position in the left-right direction, the drive shaft 52 moves in the left-right direction by the rotation of the output shaft 51 as described above. Since the drive shaft 52 and the Z-axis movement guide unit 60 are connected and fixed,
When the Z-axis movement guide unit 60 moves left and right,
The support arm 31 connected and fixed to the Z-axis movement guide unit 60 moves in the left-right direction. Therefore, when the support arm 31 moves, the inner surface torch 32 automatically follows the displacement of the outer surface torch 10 and does not cause poor welding.

As described above, since the inner torch 32 can automatically follow the lateral displacement of the outer torch 10 and correct it, the operation by the operator's intuition becomes unnecessary, and the inner torch 32 is not required. The setting work does not require skill. Therefore, when the outer torch 10 is adjusted by moving the outer torch 10 in the left-right direction, the inner torch 32 becomes the outer torch 10.
Automatically adjusts to the position of the inner torch 32, unlike the conventional manual adjustment of the position of the inner surface torch 32, regardless of the skill of the worker, the welding quality is constant and the occurrence of welding defects is prevented. can do.

Next, the control for raising and lowering the inner torch 32 in the vertical direction will be described. Here, in the case of the elevation control of the inner surface torch 32, the distance between the inner surface bead 70 (see FIG. 11) and the electrode (for example, tungsten electrode) 33 of the inner surface torch 32 is kept constant, and a stable and smooth inner surface bead 70 is obtained. Therefore, the portion heated by the inner surface torch 32 (the surface glowing portion 34) is performed by the non-contact type surface temperature sensor 43,
In order to keep the temperature of the welded portion at a set value, that is, to keep the heat input constant, the measured temperature is changed to the Z-axis movement guide unit 6.
Feedback is made to the zero side, and the inner surface torch 32 is raised and lowered by the servo motor 62 for correction. That is, instead of managing the distance between the tip of the electrode 33 of the inner surface torch 32 and the inner surface of the pipe 1, the amount of heat input to the weld is controlled, and control is performed so that the amount of heat input is always constant. I do. That is, as shown in FIG. 9, the inner torch 32 is moved up and down to
By changing the distance L with respect to the inner surface, the amount of heat input to the welded portion (surface red hot portion 34) is kept constant.

[0041] Here, when performing the vertical control of the inner surface torch 32, as shown in FIG. 6, the two elements beta ₁ and beta
₂ is compared, but the correction value is added to these factors. When the distance between the electrode 33 of the inner surface torch 32 and the inner surface of the pipe 1 fluctuates, the welding current value also fluctuates.
This is converted into an arc length, and this converted value is used as a correction value. That is, the arc length of the inner torch 32 is detected to measure the arc length, the relationship between the above-mentioned measured temperature and the arc length due to the welding voltage fluctuation is determined, and parameterized as a correction value in the moving program of the inner torch 32, The vertical movement of the inner torch 32 is corrected.

That is, the above elements β ₁ and β ₂ are β ₁
Is the reference value, β ₂ is the measured value (measured value), and the reference value β
₁ is voltage conversion data of an appropriate temperature of the molten glow portion, which is comparative stock data previously collected in an experiment or the like. Also, the measured value β ₂ is
A raw data detected measured at 3, at the time of output are translated into comparable voltage data as a reference value beta _1. The correction value has the following concept. That is, in addition to the surface temperature change, a change in the welding current voltage due to a change in the arc length also occurs at the same time. For this reason, the relationship between the arc length and the change in welding current voltage is determined in advance by experiments or the like, and the arc length can be determined by actually measuring the welding current voltage. Moreover, the relationship between the arc length and surface temperature change advance experimentally determined like, keep the comparable voltage conversion and measured values beta ₂ inside the calculator as stock data. The measured value β ₂ is compared with the surface temperature (voltage data) in the stock data extracted once by actually measuring the welding current voltage before being compared with the reference value β _1. "Measurement" correction is performed to check for external factors such as switching the value to be compared with ₁ to the surface temperature (voltage data) in the stock data and other sudden data errors. This is the concept of “correction value”.

In FIG. 6, the reference value β ₁ is obtained by setting a preset reference voltage as a parameter (data such as digitized digital data) as described above. This is set in advance in accordance with the heat input amount determined by the temperature. As described above, β ₂ is a measured value (data such as digitized digital data) obtained by converting the temperature detected by the surface temperature sensor 43 into a voltage by the temperature sensor controller 45.
Therefore, when the measured value β ₂ is larger than the reference value β _{1, the} heat input by the inner torch 32 is large, and when the measured value β ₂ is smaller than the reference value β _{1, the} heat input by the inner torch 32 is small. is there.

Hereinafter, the vertical movement control of the inner torch 32 will be described with reference to the flowchart of FIG. The reference value beta ₁ is set in step S11, step S
The measured value β ₂ calculated by the temperature sensor controller 45 is determined at 12, and a correction value is set at step S 13. The reference value β ₁ , the measured value β ₂ and the correction value are sent to the comparison determination unit 24 shown in FIG. Each is entered. The reference value β _1, which is data, and the measured value β ₂ are compared by this comparison / judgment unit 24 (see step S 14). If β ₁ = β ₂ , it is determined that the optimal heat input by the inner surface torch 32 is obtained. The vertical movement control of the inner torch 32 is not performed.

Next, as a result of data comparison between the reference value β ₁ and the measured value β ₂ in step S 14, if β ₁ <β ₂ , the measured value β ₂ is larger than the reference value β ₁ , Since the amount of heat input to the portion (surface red hot portion 34) is large, the process proceeds to step S16, and correction is performed in the direction in which the position of the inner surface torch 32 is lowered. Accordingly, the process proceeds to step S17, in which the motor drive unit 26 shown in FIG. 4 drives the servo motor 62 in the reverse direction to control the inner torch 32 to move downward. This control is performed until β ₁ = β ₂ .

Further, as a result of comparing the reference value β ₁ with the measured value β ₂ in step S 14, if β ₁ > β ₂ , the measured value β ₂ is smaller than the reference value β ₁ and the welded portion (surface Since the amount of heat input to the red heat part 34) is small, the process proceeds to step S18, and the position of the inner surface torch 32 is corrected in the upward direction. Therefore, the process proceeds to step S19, where the servo motor 6 is driven by the motor driving unit 26 shown in FIG.
2 is driven to rotate forward to control the upward movement of the inner surface torch 32. This control is performed until β ₁ = β ₂ .

Here, the vertical movement of the inner surface torch 32 has nothing to do with the X-axis movement guide unit 49, but only the vertical movement of the drive shaft 64 by the servo motor 62. The movement in the direction causes the support arm 31 to move up and down. Therefore, the vertical movement of the support arm 31 also controls the vertical movement of the inner surface torch 32, so that the heat input to the welded portion (surface red hot portion 34) can be always kept constant, and the welding failure is eliminated and stable. Welding can be performed.

As described above, the distance between the inner surface of the pipe 1 and the tip of the electrode 33 of the inner surface torch 32 can be automatically corrected so as to keep the amount of heat input to the weld constant. As a result, a smooth inner surface bead having a uniform thickness and width can be obtained.

The positions of the outer torch 10 and the inner torch 32 are quantified using data α ₁ , α ₁ , and β ₂ , respectively.
Position setting reproducibility can be ensured.

Although the position of the inner torch 32 is automatically corrected for the positional deviation of the inner torch 32 with respect to the outer torch 10 in the left-right direction and the up-and-down direction, when the position setting value of the inner torch 32 exceeds the allowable value. The alarm device 28 is driven by a signal from the CPU 22 to notify the worker. Therefore, visual monitoring during welding is almost unnecessary. Therefore, labor saving can be further achieved. In the case of such an abnormality, the operation of the entire apparatus is temporarily stopped.

FIG. 10 shows another embodiment of the support arm. At the tip of the support arm 72, an inner surface torch 32 similar to that of the previous embodiment is provided.
The support 73 is integrally protruded from the upper surface of the middle part of the base side. A shaft support 76 is fixed to the tip of a support base 75 fixed to the base frame, and a disk-shaped rotating member 77 is rotatably arranged on the lower surface of the shaft support 76. A hanging piece 78 is provided on the lower surface of the rotating member 77.
Are suspended integrally, and the column 73 is rotatably connected to the hanging piece 78 by a fulcrum shaft 74.

Therefore, the support arm 72 is rotatable in the left-right direction about the support column 73 by the rotating member 77, and the support arm 72 is rotatable in the up-down direction about the fulcrum shaft 74.

On the other hand, the base of the support arm 72 is connected and fixed to one end of a control link 79, and the other end of the control link 79 is connected and fixed to the drive shaft 64 of the Z-axis movement guide unit 60. . X-axis movement guide unit 4
9 and the Z-axis movement guide unit 60 are connected in the same manner as in the previous embodiment, and the X-axis movement guide unit 49 is fixed to the base frame. 60 itself is driven in the left-right direction. Also, the Z-axis movement guide unit 60
Is for driving the control link 79 up and down, and X
The support arm 72 is driven in the left-right direction via the Z-axis movement guide unit 60 by the
The support arm 72 is vertically driven and controlled via the control link 79 by the shaft movement guide unit 60 itself.

With the above configuration, the base of the support arm 72 is driven in the left and right direction by the X-axis movement guide unit 49, whereby the support arm 72 is rotated in the left and right direction about the support column 73, and the inner surface torch 32 is inverted. The outer torch 10 is driven in the right and left directions, and is corrected so as to follow the positional deviation of the outer surface torch 10 so that the outer surface torch 10 is colinear. Further, by driving the base of the support arm 72 in the vertical direction by the Z-axis movement guide unit 60, the support arm 72 rotates in the vertical direction about the fulcrum shaft 74, and the inner surface torch 32 moves in the opposite vertical direction. When driven, the distance L between the tip of the electrode 33 of the inner surface torch 32 and the inner surface of the pipe 1 is determined.
Is automatically corrected to keep the heat input constant.

As described above, by providing the rotating shaft in the middle of the support arm 72 and controlling the drive of the support arm 72 in the vertical and horizontal directions, the positional control of the inner torch 32 in the vertical and horizontal directions can be controlled. Can be raised.

In the above embodiment, the case where the shape of the pipe 1 is cylindrical has been described, but the present invention is not limited to these cases. For example, the present invention can be applied to a case of a square tube. In addition, the present invention can of course be applied to the case where the butted surfaces of the flat steel plates are welded and the inner bead on the lower surface is melted and smoothed.

[0057]

According to the automatic copying apparatus for the inner surface welding torch in the manufacture of the welded steel pipe according to the first aspect of the present invention, the inner surface torch is always in contact with the outer surface torch even if the position of the outer surface torch is adjusted in the left-right direction. Since the robot is automatically followed so as to be on the same line, the operation based on the intuition of the operator becomes unnecessary, and unlike the related art, the skill of setting the position of the inner torch does not require skill. Therefore, there is no occurrence of poor welding and no variation in welding quality.

Further, according to the automatic copying apparatus for the inner surface welding torch in the manufacture of the welded steel pipe according to the second aspect, the distance between the electrode at the tip of the inner surface torch and the inner surface of the workpiece can be automatically made constant. Since the heat input to the welded portion by the inner surface torch is always kept constant, a smooth inner surface bead having a uniform height and width of the inner surface bead can be obtained.

Further, according to the automatic welding apparatus for the inner surface welding torch in the manufacture of the welded steel pipe according to the third aspect, even if the position of the outer surface torch is adjusted in the left-right direction, the inner surface torch is always on the same line as the outer surface torch. As a result, work following the operator's intuition is not required, and unlike the related art, the work of setting the position of the inner surface torch does not require skill. Therefore, there is no occurrence of poor welding and no variation in welding quality. Also, the distance between the electrode at the tip of the inner torch and the inner surface of the workpiece can be automatically made constant, so that the heat input to the welded spot by the inner torch is always kept constant, It is possible to obtain a smooth inner surface bead having a uniform height and width. Thus, since the position of the inner surface torch in the left-right direction and the up-down direction is always automatically corrected, a high-quality product can be provided.

According to the automatic copying apparatus of the inner surface welding torch for manufacturing the welded steel pipe according to the fourth aspect of the present invention, the inner surface torch is provided with an alarm device for issuing an alarm when the set value of the inner surface torch exceeds an allowable value. In the case of an abnormality that greatly exceeds the position, the alarm device can easily detect the abnormality and prevent the occurrence of poor welding.
Therefore, by providing such an alarm device, visual monitoring during welding is hardly necessary, and it is possible to further reduce labor.

Further, according to the automatic copying apparatus for the inner surface welding torch in the manufacture of the welded steel pipe according to the fifth aspect, the position of the outer surface torch in the left-right direction is stored as data and numerically displayed. Even if the external torch is displaced by some external force during welding, the external torch can be immediately returned to the original position, thus ensuring the reproducibility of the external torch position setting. Can be

Further, according to the method for manufacturing a welded steel pipe according to the sixth aspect, the control of the inner surface torch in the left-right direction and the up-down direction is always automatically performed, and therefore, the position of the outer surface torch is adjusted in the left-right direction. Even if it is adjusted, the inner torch will automatically follow the outer torch so that it is always on the same line, which eliminates the need for operator intuition. No skill is required for the position setting operation. Therefore, there is no occurrence of poor welding and no variation in welding quality.
Also, the distance between the electrode at the tip of the inner torch and the inner surface of the workpiece can be automatically made constant, so that the heat input to the welded spot by the inner torch is always kept constant, It is possible to obtain a smooth inner surface bead having a uniform height and width. Thus, since the position of the inner surface torch in the left-right direction and the up-down direction is always automatically corrected, a high-quality product can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic system configuration diagram of an automatic copying apparatus for an inner surface welding torch according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part enlarged system according to an embodiment of the present invention.

FIG. 3 is a diagram showing a connection relationship between an X-axis movement guide unit and a Z-axis movement guide unit according to the embodiment of the present invention.

FIG. 4 is an overall schematic block diagram of an embodiment of the present invention.

FIG. 5 is a flowchart in the case where the position control of the inner surface torch in the left-right direction is performed according to the embodiment of the present invention.

FIG. 6 is a flowchart in the case of performing vertical position control of the inner surface torch according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram in the case of detecting movement of the outer surface torch according to the embodiment of the present invention.

FIG. 8 is an explanatory diagram in the case of detecting movement of the inner surface torch according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a distance relationship between the inner surface torch and the inner surface of the pipe according to the embodiment of the present invention.

FIG. 10 is a diagram showing another example of the support arm according to the embodiment of the present invention.

FIG. 11 is a sectional view of the pipe showing a state of an inner bead in the pipe.

FIG. 12 is a cross-sectional view of a pipe in a case where an inner bead is melted and smoothed by an inner torch.

[Explanation of symbols]

 Reference Signs List 1 pipe (workpiece) 10 outer torch 15 electric measure (first detecting means) 21 device control panel (control means) 28 alarm device 31 support arm 32 inner torch 33 electrode 34 surface glowing part 37 visual camera (second camera) Detecting means) 43 surface temperature sensor (third detecting means) 49 X-axis moving guide unit (first driving means) 60 Z-axis moving guide unit (second driving means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 9/127 B23K 9/025 B23K 9/095 501

Claims (6)

(57) [Claims] 1. An outer torch (10) which is arranged above a butt surface of a workpiece (1) to be sent out and welds a portion of the butt surface, and the outer torch (10) is used to weld the workpiece (1). The inner bead (70), which is disposed rearward in the feed-out direction and below the butt surface of the workpiece (1) and is formed on the lower surface side of the portion welded by the outer torch (10), The inner torch (32) to be melted, the inner torch (32) is disposed on the distal end side, and a support arm (31) disposed below the workpiece (1), and the support arm (31) is moved in the left-right direction. The first driving means (49) for moving the outer surface torch (1)
(1) a first detecting means (15) for detecting a positional shift in the left-right direction orthogonal to the feeding direction of the workpiece (1).
A second detecting means (37) for detecting a displacement of the inner torch (32) with respect to the position of the outer torch (10).
And the first detection means (15) and the second detection means (3
7), the first driving means (4)
9) a control means (21) for driving the inner torch (32) on the same line in the left-right direction of the outer torch (10) by driving the inner torch (10). Automatic copying device. 2. An outer torch (10) which is arranged above a butt surface of an object (1) to be fed out and welds a portion of the butt surface; The inner bead (70), which is disposed rearward in the feed-out direction and below the butt surface of the workpiece (1) and is formed on the lower surface side of the portion welded by the outer torch (10), The inner torch (32) to be melted, the inner torch (32) is disposed on the distal end side, and a support arm (31) disposed below the workpiece (1), and the support arm (31) is moved vertically. Second driving means (60) for moving the inner torch (3)
The third detecting means (43) for detecting the surface temperature of the surface glowing portion (34) formed by heating in step 2), and receiving the temperature detection signal from the third detecting means (43) to be welded. The second drive means (60) is driven to convert the heat input amount into a predetermined heat input amount, and the electrode (33) at the tip of the inner surface torch (32) and the work (1) are heated. An automatic copying apparatus for an inner surface welding torch in the production of a welded steel pipe, comprising: a control means (21) for keeping a distance (L) from a lower surface constant. 3. An outer torch (10) which is arranged above a butt surface of a workpiece (1) to be fed out and welds a portion of said butt surface, and said outer torch (10) is used to sew said workpiece (1). The inner bead (70), which is disposed rearward in the feed-out direction and below the butt surface of the workpiece (1) and is formed on the lower surface side of the portion welded by the outer torch (10), The inner torch (32) to be melted, the inner torch (32) is disposed on the distal end side, and a support arm (31) disposed below the workpiece (1), and the support arm (31) is moved in the left-right direction. The first driving means (49) for moving the supporting arm (31) and the first driving means (49) are linked so as to drive the support arm (31) only in the left-right direction, and the vertical direction of the support arm (31). Move only the second Driving means (60), first detecting means (15) for detecting a lateral displacement of the outer torch (10) in a direction perpendicular to the direction in which the workpiece (1) is fed out, and the outer torch (10). ), A second detecting means (37) for detecting the displacement of the inner surface torch (32) with respect to the position, and the surface temperature of the surface glowing portion (34) formed by heating by the inner surface torch (32). A third detecting means (43) and the first detecting means (15);
The first driving means (49) is driven by the position detection signal from the second detection means (37) and the outer surface torch (1).
The position of the inner torch (32) is set on the same line in the left-right direction of (0), and the third detecting means (43) is set.
Receiving the temperature detection signal from the sensor and converting it into the amount of heat input at the welded portion, and driving the second drive means (60) so that the heat input becomes a preset amount of heat input, the electrode ( 33. An automatic copying apparatus for an inner surface welding torch in the production of a welded steel pipe, comprising: a control means (21) for maintaining a constant distance (L) between the lower surface of the workpiece (1) and the lower surface of the workpiece (1). 4. An apparatus according to claim 1, further comprising an alarm device for issuing an alarm when a set numerical value of said inner surface torch exceeds an allowable value. Automatic copying machine for inner surface welding torch in the production of welded steel pipes. 5. The method according to claim 1, wherein the position of the outer surface torch in the left-right direction is stored as data and numerically displayed. Automatic copying machine for inner welding torch. 6. An outer torch (10) which is arranged above a butt surface of an object to be fed (1) to be fed out and welds a portion of the butt surface, and the outer torch (10) is used to weld the object (1). The inner bead (70), which is disposed rearward in the feed-out direction and below the butt surface of the workpiece (1) and is formed on the lower surface side of the portion welded by the outer torch (10), The inner torch (32) to be melted, the inner torch (32) is disposed on the distal end side, and a support arm (31) disposed below the workpiece (1), and the support arm (31) is moved in the left-right direction. The first driving means (49) for moving the supporting arm (31) and the first driving means (49) are linked so as to drive the support arm (31) only in the left-right direction, and the vertical direction of the support arm (31). Move only the second Driving means (60), first detecting means (15) for detecting a lateral displacement of the outer torch (10) in a direction perpendicular to the direction in which the workpiece (1) is fed out, and the outer torch (10). ), A second detecting means (37) for detecting the displacement of the inner surface torch (32) with respect to the position, and the surface temperature of the surface glowing portion (34) formed by heating by the inner surface torch (32). A third detecting means (43) and the first detecting means (15);
The first driving means (49) is driven by the position detection signal from the second detection means (37) and the outer surface torch (1).
The position of the inner torch (32) is set on the same line in the left-right direction of (0), and the third detecting means (43) is set.
Receiving the temperature detection signal from the sensor and converting it into the amount of heat input at the welded portion, and driving the second drive means (60) so that the heat input becomes a preset amount of heat input, the electrode ( 33) a control means (21) for maintaining a constant distance (L) between the lower surface of the workpiece (1) and the outer surface torch (10).
The object (1) is welded by the control means (21) and the first drive means (49) when the welded portion comes to the position of the inner surface torch (32). Set the horizontal position of the inner torch (3
The welding is performed according to 2), and the surface glowing portion (3
The temperature of step 4) is detected by the third detection means (43), and the control means (21) controls the heat input amount at the welded portion to be constant.
A feedback to the second drive means (60) to control the vertical position of the inner surface torch (32).