JPS6040670A - Outside circumferential welding method of patch in saddle type welding - Google Patents

Abstract

PURPOSE:To prevent undercut and decrease in strength and to perform automatically multi- layer welding at a high speed by maintaining the specified angle and distance of a torch with and from the outside circumferential end face of a patch, determining the upsetting position of multi-layer welding and controlling the torch. CONSTITUTION:Multi-layer welding is executed while the specified angle and distance of a torch axis with and from the outside circumferential end face of a patch 4 are maintained by controlling the angle theta of inclination with respect to the central axis of a nozzle 7 and the X-axis moving in the direction perpendicular to the central axis. The displacement DELTAZ in the central axial direction of the nozzle where the weld beads of the 2nd and succeeding layers exist between the weld beads of the 1st layer is measured. The measured value DELTAZ is then integrated with the tangential trigonometric function tanbeta of the angle beta at which the outside circumferential end face 6 directed by the welding torch 7 inclines with respect to the central axis of the nozzle 7. The position further from the nozzle 7 in the X-axis direction as compared with the upsetting position of welding set nearer the face 6 of the 1st layer by as much as the length corresponding to the integrated value X is set in the upsetting position of welding near the face 6 in the weld beads of the 2nd and succeeding layers, then welding is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention intersects the main pipe of a large-diameter pipe and the nozzle of a small-diameter pipe at right angles to the axis, and creates a saddle-shaped weld line along a three-dimensional intersecting curve formed at the intersection. Regarding the welding method in which the attached plate is further welded to reinforce the joint after welding (hereinafter referred to as saddle welding), the precision of multi-layer excess welding is particularly important when automatically welding the outer peripheral edge of the plate. 1) Provides a method for welding the outer periphery of a backing plate that can be easily performed.

When carrying out the saddle welding described above, there is a level difference (height difference) in the direction of the center axis of the nozzle on the outer peripheral end surface of the plate, and the end surface is formed so as to be orthogonal to the cylindrical main pipe. When attempting to uniformly weld the outer peripheral end face with a welding torch, it is necessary to control the inclination angle of the torch axis so that a constant angle is maintained with respect to the end face, and furthermore, The welding in this area is a multilayer weld, and if the welding reversal position near the outer peripheral end face is too close, an undercut will occur, and if it is too far, the welding strength will decrease, so it is necessary to perform reliable position control. Conventionally, there is no automatic welding equipment that can be used for this purpose, so manual welding by skilled technicians has been relied upon, resulting in low productivity and processing costs. There was a problem.

The present invention has been made in view of the above circumstances, and its purpose is to maintain a constant angle of the welding torch with respect to the outer peripheral end surface of the plate and to determine the welding reversal position in multi-layer welding. By realizing a control means, it is possible to promote automation of this type of welding and to achieve stable welding accuracy.

Therefore, the present invention particularly relates to step welding, in which the angle of inclination (θ) of the welds 1 and 1 with respect to the central axis of the nozzle,
By controlling the X-axis that moves in a direction perpendicular to the central axis, the second layer can be Displacement in the nozzle center axis direction between the weld bead and the first layer weld heat after
), and this measured value (Δ2) and welding 1-
- The outer circumferential end face of the first layer is multiplied by the tangent trigonometric function (h11β) of the inclination angle ψ with respect to the central axis of the nozzle, and the outer circumferential end face of the first layer is Compared to the welding reversal position which is set closer to the welding reversal position, a position farther away from the nozzle in the X-axis direction is set as the welding reversal position closer to the outer peripheral end surface in the welding heat of the second layer and thereafter, and the welding is performed by 1. This is characterized by a welding method in which the joint is reversed at this welding reversal position, and while the distance and angle to the outer peripheral end face are held constant, the distance from the outer peripheral end face is also maintained constant at the welding reversal position. Automatic control is now possible, which makes it possible to achieve the two desired objectives.

Embodiments of the present invention will be described below with reference to accompanying drawings.

FIG. 1 is a diagram schematically showing a welding robot and a workpiece to be welded according to the method of the present invention. The workpiece has a main pipe (1) of a large diameter pipe and a nozzle (2) of a small diameter pipe The nozzle (2) is orthogonally branched from the main pipe (1) and the nozzle (2) is joined at right angles, and the saddle-shaped weld line (3 ) are automatically welded and integrated by the welding robot.

In order to further strengthen the joint part, the second workpiece has a plate (4) attached to the surface of the main pipe (1) around the nozzle (2), but the plate (4) is saddle-welded. A curved ring shape having an inner peripheral end surface (5) concentric with the line (3) and an outer peripheral end surface (6) having a similar shape concentrically can be attached to the surface of the main pipe (1). 1, the bird's-eye view of the arrangement shown in FIG.
) and the surface of the main pipe (1) are welded.

The welding robot has an Ro axis that revolves around the center axis of the nozzle (2), two axes that move up and down parallel to the center axis of the nozzle (2), and two axes that are orthogonal to the two axes. Welding I-
The welding torch (7) is provided with an inclination angle (
The distal end has an S axis that can be swung in the vertical direction so that the position can be changed.

With this welding robot, the saddle-shaped welding line (3), the contact plate (4)
), when welding the inner circumferential end surface (5) and outer circumferential end surface (6), operate the RO axis, z axis, X axis, and S axis to perform welding 1-
- Automatically direct the tip (7) to each weld line correctly.

Although it is possible to perform welding continuously, welding along the outer circumferential end surface (6) is particularly difficult since the end surface intersects perpendicularly to the curved surface of the main pipe (1) as described above.
The inclination angle of the tip (7) (needs to be changed from time to time according to the sliding movement).

Therefore, the welding torch (7
) in a position slightly in front of the point where it is pointing.
While contacting the copying stylus (8), copying control is performed on the X axis, zIIIllI performs saddle shape calculation control, and R
, axes, the position take is stored in the storage section for each unit rotation angle, and the position take is output for each operating axis during welding.

The inclination angle of the welding torch (7) (
It is necessary to control the inclination angle (θoX second
(see figure), the radius @) of the main pipe (1), and the outer peripheral end face (
Since the distance (L) leading to 6) is a predetermined and unchanging value, it is stored as a reference value in the storage unit of the control device so as to be readable, and the rotation angle of the zero axis, Namely, welding!・Detect the rotation angle (ω) (see Fig. 4) at which the chi (7) orbits around the central axis of the nozzle (2) with the apex part (a) as the base point (see Fig. 4) using an appropriate rotation angle detector. At least, this detected value ω and each stored value 00, R,
The inclination angle (θ) of the welding torch (7) is determined from L and controlled.

In Fig. 3, considering the outer circumferential end face (6) at any position other than the apex (A), this end face is perpendicular to the surface of the main pipe (1), so naturally this extension line is the main pipe (1). 1) intersects with the center (0).

Therefore, the central axis of the nozzle (2) (this central axis is the main pipe (1)
passing through the center (0) of), the end surface (6) and the main pipe (
1) and the line connecting the center (0) of the welding point (C), the outer peripheral end face ( 6) The inclination angle of welding 1--chi (7) (is the third
As is clear from the figure, 0-Oo+β (1).

The nozzle (2) is attached to the apex (a) of the welding point above.
If the height difference in the direction of the central axis is 2, then cosβ-''
Two is jin...(2) The formula ■ holds true.

On the other hand, regarding 2, as is clear from FIGS. 3 and 4, 2=几-JR2-L25in2 (IJ-(3)).

From both formulas (1) and (2) J( is obtained.

Therefore, from both equations (1) and (4), 几 becomes.

Therefore, by sequentially controlling the inclination angle of the torch axis of the welding torch (7) so that equation (5) holds true,
It is possible to always maintain the angle that the torch axis of welding 1 to 1 (7) makes with the outer peripheral end surface (6) of the contact plate (4) constant.

However, the welding along the outer circumferential end surface (6) is a multilayer welding as shown in Fig. 5, and it is necessary to weave each welding layer, but the position of the X axis for weaving is The welding reversal position (A1) that serves as the reference point for the first layer, that is, the reversal position closer to the outer peripheral end surface (6), is the position stored when tracing with the tracing stylus (8) for teaching before welding. There is no problem as long as it is based on the take.

However, similar welding reversal positions (A2) (A8), etc., which serve as reference points for weaving from the second layer onwards, are as follows:
As is clear from FIG. 5, the two positions differ in each of the X-axis directions.

Of these, the displacement in two axial directions is controlled in parallel to the heat of the first layer by controlling the arc current value to be constant, so the height displacement (Δ2) with respect to the first layer is This can be determined by location.

On the other hand, the displacement (X) in the X-axis direction is as follows: Goz-1nβ (6), then X-Δz×0β (7), so the 2nd R-th inversion position (A2) is the first
The nozzle (2
) can be set at a position far away from the central axis in the X-axis direction.

Similarly, the inversion position (83) of the third layer is X2-ΔZ2
X fall β, and it will be reversed at a further distant position.

In this way, the reversal position for the second and subsequent layers is determined by the displacement (Δ2) in the central axis direction of the nozzle (2) between the weld bead and the weld bead of the first layer, and the orientation of the welding torch (7). The welding reversal position of the first layer is moved by the length corresponding to the integrated value (X) of the tangent trigonometric function (+, Inβ) of the inclination angle ψ) with respect to the outer peripheral end face (6) or the central axis of the nozzle (2). (AI) is set at a position farther away from the nozzle (2) in the X-axis direction.

In this way, when the displacement (Δ2) and the inclination angle ψ) and the other two variables are measured, the welding reversal position of each layer of the extra layer can be accurately set.

Incidentally, the tilt angle ψ) is clear from the above equation (2), but
It can be determined from the values of R and Z by β-0° and -11.

Next, the effects of the present invention are as follows.

Based on the X-axis and two-axis information of the outer peripheral end surface (6) of the contact plate (4) memorized during the teaching prior to main welding, the weld bead of the second and subsequent layers in multilayer reinforcement welding is determined as described above. 1st layer weld bead inversion position (4) stored as 2-axis information
) in the central axis direction of nozzle (2) (Δ2
) and the inclination angle qJ) of the outer circumferential end surface (6) toward which the welding torch (7) is oriented with respect to the nozzle (2) center axis. Since it is possible to precisely control the position of the weld l. Furthermore, since the welding reversal position can be maintained at an appropriate distance from the outer circumferential end surface of the plate, highly accurate welding can be performed without any disadvantages such as undercut or reduction in welding strength.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a welding process according to the present invention and a workpiece, Fig. 2 is a partial longitudinal cross-sectional view along the apex of the workpiece, and Fig. 3 is a longitudinal cross-section along a setting position other than the apex. 4 is a plan view of the workpiece, and FIG. 5 is an enlarged view of the contact plate portion in FIG. 1. (1)...Main pipe, (2)...Nozzle, (3)...
Saddle-shaped welding line, (4)...Welding plate, (5)...Inner circumferential end face, (6)...Outer circumferential end face, (7)...Welding torch.

Claims (1)

[Claims] 1 The main pipe (1) of the large diameter pipe and the nozzle (2) of the small diameter pipe are crossed at right angles to the axis, and after welding a saddle-shaped weld line (3) along the interpenetration curve formed at the intersection, This saddle-shaped weld line (3)
A contact plate (4) that can be attached to the surface of the main pipe (1) and has an inner circumferential end surface (5) that is congruent with the outer circumferential end surface (5) and an outer circumferential end surface (6) that is similar to the main tube concentrically, The main pipe around the nozzle (2) (
1) In saddle welding in which the inner peripheral end face (5) and the outer peripheral end face (6) are automatically welded by a welding torch (7) attached to the surface, the welding torch (7) is attached to the nozzle (2). By controlling the inclination angle formed with respect to the central axis of When performing multi-layer overfill welding while holding the position constant, measure the displacement (A2) in the direction of the center axis of the nozzle (2) where the weld beads of the second and subsequent layers exist between the weld beads of the first layer. At the same time, this measured value (A2) and the outer peripheral end surface (6) toward which the welding torch (7) is directed are determined by the nozzle (2).
) tangent trigonometric function (t, 1n
β) and the nozzle ( 2) is set as a welding reversal position near the outer peripheral end face (6) in the welding heat of the second and subsequent layers in the X-axis direction, and the welding torch (7) is set at this welding reversal position. A method for welding the outer periphery of the plate, which is characterized by inverting the outer periphery of the plate.