JPS5820704B2 - Continuous overlay automatic welding method for approximately hemisphere - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous overlay automatic welding method for a substantially hemispherical body.

Conventionally, for heaters, reactors, pressure fluid holding vessels, etc., spherical welded structures having a partial shape of a sphere, such as a hemisphere or a ball shape, have been used as the whole or a part of the pressure vessel. .

Overlay welding is often performed on the inner surface of a welded sphere structure using a corrosion-resistant or heat-resistant alloy, but conventionally, this inner surface overlay welding was performed around the center of the sphere. A method is used in which welding is carried out manually in a downward direction while rotating the workpiece.

In this method, for internal overlay welding, the welding work is once completed and stopped each time the workpiece rotates once, and then the workpiece is tilted at a predetermined angle and welding is carried out on the concentric circle of the top. It is now possible to do this.

However, in the above welding work, the workpiece is stopped once every time it rotates and then moved to the next concentric circle. There may be some leftover parts.

In this case, it will be necessary to rework and weld this part.

Furthermore, when the welding end portion is wrapped around the welding start end portion, there is a drawback that it takes time to modify the wrapped portion.

The present invention has been made in view of the above-mentioned drawbacks of the conventional art.The present invention fixes the hemisphere so that the opening surface is almost parallel to the top surface of the rotary table, and also aligns the welding head with the welding head on the vertical axis passing through the center of the hemisphere. Welding is performed while rotating the rotary table, and when the welding material rotates approximately once on a concentric circle and reaches a predetermined position, the detection unit detects this, and the signal from the detection unit turns the rotary table into a hemispherical ball. While rotating the axis containing the center as the rotation center at a predetermined tilt speed and a predetermined displacement tilt angle, the weld is displaced in a helical manner to the next concentric circle, and each rotation of the rotary table is performed as in the conventional method. It is an object of the present invention to provide a continuous overlay automatic welding method for a substantially hemispherical body, which allows continuous welding without the need to stop welding.

Next, the present invention will be explained according to the drawings which are one embodiment.

1 to 5, 1 is a substantially hemispherical continuous overlay automatic welding device, and this device 1 mainly includes a positioner 2,
Manipulator 23, welding device 35, and control device 4
It consists of 8.

The positioner 2 includes a rotary table 3, an axle 4,
It is composed of a sector gear 5, an arm 6, and a frame T.

As shown in FIG. 4, the rotary table 3 has a substantially regular hexagonal shape, and has three pedestals 8 at diagonal positions on its upper surface.
Six clamp jigs 9 having protrusions 10 on the upper part are provided, and a gear 11 is provided at the center of the lower surface.
and a king pin (both not shown) having a burner insertion hole in the center for preheating the workpiece to be welded, and is rotatably supported by the axle 4 via the king pin.

The axle 4 has a box shape, and the sector gear 5 and the arm 6 are fixed to both ends thereof.A shaft 13 is fixed to the outer upper ends of the sector gear 5 and the arm 6, respectively. It is rotatably supported by the upper end of a support base 7a provided on the upper surface of the frame 7.

A motor 14 and a reducer 15 connected to the motor and having a gear 16 on the upper part are provided on the side of the axle 4.
The gear 16 meshes with the gear 11 fixed to the lower surface of the rotary table 3. The frame 7 has a substantially quadrangular shape, and has a motor 17 on its upper surface and a gear 19 connected thereto. A reduction gear 18 is provided, and a gear 19 meshes with the sector gear 5.

A work landing 20 is placed at an appropriate position on the frame 1.
and ramps 21 are provided, and the support stand 7a
A red warning light 22 is provided above.

The manipulator 23 is mainly mounted on a fixed base 24° column 2.
5. It is composed of a crosshead 30 and an upper boom 32.

The stationary stand 24 is fixed to the floor, has a motor (not shown) provided therein, and has the column 25 rotatably supported on its upper surface.

The column 25 consists of two box-shaped pillars made of steel plates, and a landing 26 is provided at the top, a motor 27 and a red warning light 28 are provided at the top of the landing 26, and a climbing ladder is provided at the bottom. 29 are provided.

Further, limit switches (not shown) are provided at appropriate positions in the upper and lower parts.

The crosshead 30 has a box shape made of steel plate, and is mounted so as to be movable up and down between the two columns 250 by guide rollers 31a.

The guide roller 31a is connected to a motor 27 via a chain 27a, and the guide roller 31a is driven by the motor 27.
The end position of the vertical movement is limited by limit switches provided at the top and bottom of the column 25.

A boom 32 is still supported within the crosshead 30 so as to be movable in the horizontal direction by guide rollers 31b.

The boom 32 has a box shape made of steel plate, and a workbench 33 on which a worker can ride is provided at the tip thereof. A welding device 35 is provided at the bottom of the workbench 33 via a support fitting 34. ing.

This boom 32 is driven by a guide roller 31 from a first drive t)ff of a motor (not shown) provided on the crosshead 30.
b, and is movable in the horizontal direction within a certain range using a limit switch (not shown).

The welding device 35 mainly includes a welding head 36, a hoop reel (not shown), a flux spreader 37, a flux recovery device 38, and a welding power source 39.

A flux spreader 37 is provided above the welding head 36 and has a hopper 41 that stores flux and a cylinder 42 that opens and closes a supply port of the hopper 41 .

Still, a hoop reel for supplying the electrode hoop to the welding head 36 is fixed to a pedestal (not shown) provided at an appropriate location on the positioner 2.

The flux recovery machine 38 is comprised of a recovery machine main body 43 and a blower 45, each having a collector/one tar (not shown) at the bottom and a damper 44 at the bottom, which are connected to each other via a hose 46. is connected, and the collection machine main body 4
3 is connected to the welding head 36 via a hose 47 that passes through the inside of the boom 32.

The control device 48 includes a main operation panel 49 that can be operated on the ground, a positioner operation panel 50 that can be operated by a button pull, a manipulator operation panel 51, and a control panel.

The positioner operation panel 50 and the manipulator operation panel 51 are provided on the workbench 33 provided at the tip of the boom 32 of the manipulator 23, and by switching, each of the operation panels 49, 50, and 51 can be operated independently. It is now possible to do so.

The main operation panel 49 is a tester-type, dust-proof type made of free-standing steel plate, and includes a key switch for operation power supply, 3
The operation changeover switch and its display, each motor ammeter as the positioner-related panel, the tilt angle and rotation speed display of the rotary table 3, the positioner rotation and tilt display, and the horizontal display of the boom 32 as the manipulator operation panel. Each folding button for directional movement (fast forwarding), lifting and turning, welding-related panel surfaces, and each motor control device as a control panel,
Necessary instruments such as a welding condition instruction recording device are provided.

Still, the positioner operation panel 50 and the manipulator operation panel 51 are also provided with necessary instruments and the like, as described above.

Next, the operation of the substantially hemispherical continuous overlay automatic welding apparatus 1 having the above configuration will be explained.

First, the hemispherical workpiece 52 is placed on three pedestals 8 provided on the top surface of the rotating tape A3 of the positioner 2.
20 placed so that the opening surface 52a containing the spherical center is parallel to the rotating tape A3, and then the 6
The protrusion 10 on the top of each clamping jig 9 is engaged and fixed to the surface 52a.

Then, the motor 17 provided on the frame 7 is started, and the gear 19 and the sector gear 5 are engaged to rotate about the shaft 13 as a fulcrum, and the rotating tape A3 is tilted at 90 degrees with respect to the horizontal direction.

Next, the motor provided in the fixed base 24 of the manipulator 23 is started to rotate the column 25, and the column 2
The cross head 3 is driven by the motor 27 provided on the top of the cross head 5.
0 is raised or lowered to align the axis of the boom 32 with the spherical direction of the workpiece 52.

At the same time, after positioning the crosshead 30 at a predetermined height,
The motor provided in the welding device 35 is started to move the boom 32 horizontally, and the boom 32 is moved forward from the position shown by the solid line to the position shown by the dotted line in the figure.
Set the ball to be located on a vertical line that includes the center of the ball.

Then, preparation for welding is completed by supplying the required strip electrode (hoop) to the welding head 36 of the welding device 35 and supplying flux to the flux spreader 37, respectively.

Next, a welding control method using this device 1 will be explained.

Figure 6 shows this welding control system, and shows the command welding speed (S), the inner diameter of the workpiece [F]), the width of the strip electrode), the displacement transition bead length (G), and the Rotary table 3 detected by the tilt angle detection device of the positioner shown in the figure
The angle of inclination () with respect to the perpendicular P of is input, and the calculator 53 performs a predetermined calculation on this, and the result is output to the rotating electric motor governor 54 and the tilting governor 57 of the rotary table 3 to rotate the rotary table. Since a predetermined welding control is performed by controlling the speed and inclination speed, this will be explained in detail below.

First, in order to form a continuous overlay bead, there are two methods: one is to form a spiral bead that is entirely non-concentric, and the other is to form a bead that is mostly concentric and has a part that has a displaced part that transitions into an inner and outer concentric circle. Two methods are possible, but the former is not practical because the welding control becomes extremely complicated and the equipment becomes larger and more expensive.

On the other hand, for the latter, two methods are considered: a method in which the transition length G of the displacement part to the inner and outer concentric circles is made constant as shown in Figure 8A, and a method in which the angle α of the displacement transition part is made constant as shown in Figure 8B. However, in case B, the angle β of the displacement part becomes smaller as it goes inward, so as shown in FIG.
The bead widths 1 and 1' of the built-up beads 100 and 100' formed by this tend to become narrower on the inside.

Therefore, if the respective welding speeds v and v' of the beads 100 and 100' are equal, the amount of build-up per unit time of both beads 100°1001 is the same, so the welding speed of the bead 100'
The bead is thicker than the bead 100.

In order to prevent this, the welding speed must be controlled by changing the angle β, which requires extremely complicated control.

However, in the method shown in FIG. 8A, since the angle β of the displacement transition portion is constant, the speed of this portion may be constant.

Therefore, welding starts from the outer concentric circle to the inner concentric circle
When the rotational table 3 reaches the tilting speed R calculated by R=-πD .-, it is detected by a limit switch (not shown) and a command is given to the table tilting electric motor governor 57. The displacement inclination angle Δθ=θ'-θ is determined from the inclination angle θ of the rotating tape A3 at that time and the angle θ' during the tilting, and this value is sent to the matching rotation 59.

In the coincident rotation 59, it is compared with △θ= -X 360 calculated based on the given welding conditions, and when both match 1πD, the signal is sent to the comparator 56, and the motor 7 is sent to the table tilting governor 57. issue a stop order.

In this way, the transition position from the outer concentric circle to the inner concentric circle can be accurately and easily managed by Δθ by keeping the displacement transition bead length G constant.

This state is shown in FIG. 9, where the distance between the inner and outer concentric beads varies by Δθ with respect to the spherical center O.

Next, we will explain the welding control inside the concentric area.As is clear from FIG.
Although the diameter d of the weld zone changes with θ, the welding speed must be constant, so it is necessary to control the rotation speed γ of the rotary table 30 so that the circumferential speed at the weld zone is constant.

By the way, if the welding target position is set to aim at the lowest point Q of the workpiece 52 as shown in FIG. As shown in Figure B, it is necessary to weld at a point behind the lowest point Q with respect to the rotational direction of the workpiece 520, and normally this point has an angle of 1 degree between the tangent of point K and the horizontal line. The points before and after are selected.

In this way, if welding is performed by arranging the electrodes displaced from the line passing through the center of the ball, and the welding speed is controlled so that the actual circumferential speed of the arc point is constant, problems as shown in Figure 11 occur. occurs.

That is, when the deviation from the center line of the strip electrode is l,
This shift l is constant for both the outer concentric bead b1 and the inner concentric bead b2, and since the strip electrode width T is also constant, the bead b1. b2 bead width 'W1 e
w2 satisfies Wl > w2.

Therefore, if the welding speeds of both beads are the same, and other welding conditions are constant, the amount of deposited metal will be the same, and the thickness of the inner bead b2 will be larger than that of the outer bead b1.

In overlay welding, keeping the overlay thickness uniform is an essential requirement from the perspective of maintaining the uniformity of the components of the overlay metal, so welding speed should be kept constant at the actual welding point. This means that it cannot be controlled so that

Therefore, the present invention employs the following special control method.

In other words, in Fig. 12, Fig. B is a sectional view taken along line B-B of Fig. A, and the actual welding point is the point, but the welding point is the intersection J of the perpendicular P passing through the ball center 0 and the workpiece 52. It is assumed that the rotation speed γ of the welded object 52 is controlled so that the tangential speed of the welded object 52 at these five points is constant.

Distance from the rotation axis of the workpiece 52 to point 5 m 1
Since m m2 is m2<ml, the circumferential velocity 2 at 5 points
Assuming that πm2γ is constant, the actual welding speed at point K becomes slower as it goes inward.

On the other hand, the bead width becomes narrower toward the inside, and the increase in welding speed and the decrease in bead width cancel each other out, and the thickness of the welding bead on the inner and outer concentric circles becomes almost constant, making it uniform. Welding can be done.

For example, the diameter of the workpiece to be welded D = 3800 mm, the strip electrode width T = 50 mvt, the final inner diameter 200 mrn,
When welding is performed under the condition that the final inclination angle θmax = 87° and the point is 1° upward slope from point Q, the bead width b1nvt of the innermost concentric bead is compared to the bead width bmax of the outermost concentric bead. It becomes narrower by about 5.42%, but
On the contrary, the welding speed has increased by about 5.37%, so they cancel each other out and the bead height remains almost constant.

As explained above, in the present invention, the command welding speed S
, the inner diameter D of the welded object, the strip electrode width T, and the displacement transition bead length G between the inner and outer concentric beads are input into the calculator 53 as constants, and the inclination angle θ measured by the inclination angle detection mechanism provided in the positioner 2 is calculated. Constant detection and this is also the above calculator 5
3, the welding head is positioned slightly backward in the rotational direction from the lowest point of the workpiece, and concentric internal overlay welding is performed based on the above input data by γ=S/πDc.
Issue a command to the table rotation governor 54 to rotate the rotary table 3 at the rotation speed γ calculated by osθ,
In the part where the outer concentric circle transitions to the inner concentric circle, the position is detected by a limit switch provided in the positioner 2, and this signal causes the rotation chi πDG pull 3 to move at the tilting speed R calculated by TR=-.-. In order to tilt the table, a command is issued to the electric motor governor 57 for tilting the table, and even during tilting, the tilt angle θ' is detected, the table rotation speed γ is calculated by cos θ' of γ=SΔ, and the rotation speed is calculated. While controlling every moment, the difference △θ = θ' - θ from the tilt angle θ before tilting is calculated, and this difference is calculated based on the above input data, △θ = -X36.
The πD comparator 56 determines whether or not they match with 0. If the two match, a stop command is issued to the table tilting electric motor governor 57.

In this way, the transition from the outside to the inside is completed with a constant displacement distance, and using the inclination angle θ' at the time of completion, the rotating table 3 is moved at a speed calculated by γ=S/πI) cos θ'. Rotate it to perform overlay welding on the inner concentric part.

By repeating the above operation, the approximately hemispherical workpiece 52
Continuous overlay welding can be performed on the inner surface of the welding section at a set welding speed from the outer concentric circle to the inner concentric circle.

In FIG. 6, the actual rotation of the rotary table 3 is detected by the table detection means 55, and a signal of the detected actual rotation speed γ' is sent to the table rotation electric motor governor 5.
At the same time, the signal is sent to the computer 53, and the table rotation electric motor governor 54 is actuated by the above signal to feedback-control the rotation speed of the rotary table 3.

On the other hand, the above input causes the calculator 53 to
The actual welding speed S/=γ'πDCO3θ' of the welding device 35 based on the actual rotational speed γ' is calculated and displayed.

Further, the actual tilting speed of the rotary table 3 is also detected by the detection means 58.
The detection signal is fed back to the table tilting electric motor governor 57 to tilt the rotary table 3 at a set speed R.

As is clear from the above description, the present invention allows a positioner having a rotary tape A that can freely rotate and tilt to hold a substantially hemispherical shape so that the rotation center line and the tilt center line of the rotary table pass through the center of the sphere. , so that the arc point of the strip electrode fed from the welding head held by the manipulator so that its position can be adjusted is located slightly behind the lowest point of the substantially hemispherical body held by the rotating tape A in the direction of rotation thereof. Arrange the head below, and input the command welding speed (S), the inner diameter of the approximately hemispherical body [F]), the width of the strip electrode (Tχ, the displacement transition bead length (G) k, and the positioner's setting on the positioner operation control computer). The tilt angle of the rotary table (θ
), the rotational speed of the rotary table (γ) γ=S/πD cosθ calculated by the computer, the rotary table inclination speed (R) R=ST/πDG, and the displacement angle (toward) at the time of transition Δθ=360T /πD, and welding is performed while controlling the operation of the positioner using these outputs. Therefore, overlay welding with a constant overlay thickness can be performed on the inner surface of a substantially hemispherical body at a predetermined welding speed. In addition, the displacement transition bead G between the inner and outer concentric beads is kept constant, the inclination angle θ of the rotating tape A is constantly detected by the inclination angle detection mechanism provided in the positioner, and this is input into the computer, and the calculated value is calculated by the computer. , number of rotations of the rotary table (1)
, the tilting speed (2), and the displacement angle (to) at the time of transition are controlled to 0 lbs.
There is no need to stop the welding work for each rotation, and overlay welding can be performed automatically and continuously in an almost spiral shape from the outer concentric circle to the inner concentric circle.

[Brief explanation of drawings]

Fig. 1 is a front view of a substantially hemispherical continuous overlay automatic bath welding device according to the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Figs. A drawing showing a positioner,
Fig. 3 is a side view, Fig. 4 is a plan view, Fig. 5 is a front view, Fig. 6 is a block diagram of the control method, and Fig. 7 is a tilted state of the approximately hemisphere (workpiece) and rotary table. 8A and 8B are plan views showing the transition part from the outer concentric circle to the inner concentric circle of overlay welding on the inner surface of a substantially hemispherical body, and Figure 8 C is an enlarged view of the transition part. , FIG. 9 is a sectional view showing the displacement inclination angle Δθ and displacement inclination speed R of the rotary table, FIG. 10 is a schematic diagram showing the position of the welding head,
FIG. 11 is an explanatory diagram showing the relationship between the position of the welding head and the peed width of the inner and outer overlay beads, and FIG. 12 is an explanatory diagram showing the relationship between the welding position and the speed control position. DESCRIPTION OF SYMBOLS 1... Approximately hemispherical continuous overlay automatic welding device, 2... Positioner 13... Rotating table, 23... Manipulator, 35... Welding device, 36... Welding head,
48... Control device, 52... Welded object (approximately hemisphere)
, 53... Calculator, 54... Rotating motor governor, 55... Tape A detection means, 57... Table tilting motor governor, 58... Detecting means, 0... Ball center, θ ...lowest point, K...rear position, X...starting point.

Claims (1)

[Claims] 1. A method for automatically welding a build-up bead consisting of a concentric build-up bead and a displacement part transition bead that continues the inner and outer concentric build-up beads on the inner surface of a substantially hemispherical body, the rotary table being rotatable and tiltable. The arc point of the strip-shaped electrode is fed from the welding head, which is held by a positioner having a substantially hemispherical shape so that the center line of rotation and the center line of tilting of the rotating table pass through the spherical center, and is held by a manipulator so that the position can be freely adjusted. The above-mentioned RAD is arranged so that it is located slightly backward in the direction of rotation from the lowest point of the substantially hemispherical body held on the above-mentioned rotary table, and the command welding speed is given to the position length and operation control calculator. Inner diameter of hemisphere [F]), width of strip electrode (
T) Displacement transition bead length (G shadow and rotary table rotation speed (γ) calculated as γ=S/πDcosθ by inputting the rotary table tilt angle (!9) from the tilt angle detection mechanism provided in the positioner) and rotary table tilting speed (R) calculated by R=sT/πDG, △θ=360'l'/
A continuous overlay automatic welding method for a substantially hemispherical body, characterized in that the transition displacement angle (Δθ) calculated by πD is outputted, and welding is performed while controlling the operation of a positioner.