JPH06246444A - Method for inspecting weld zone - Google Patents

Abstract

PURPOSE:To detect the shape of a groove formed on butt ends between members to be welded and a shape of a weld bead to this groove and to perform welding under welding conditions corresponding to the shapes thereof. CONSTITUTION:After the weld bead 4 is formed in a state that the root bottom of the groove 3 blocked up on the opposite side of the groove 3 for penetration welding from one side formed on the butt ends of the members 1 and 2 to be welded, a laser beam LB is scanned by a laser beam head 6 in the direction to cross the groove 3 extending over this groove 3 and the surface of the member 1 and 2 to be welded on both sides thereof, the reflected light image is picked up by a CCD camera 7 and a cross-sectional shape of the groove 3 is detected based on a picked-up picture thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a groove shape, a weld bead shape and the like.

[0002]

2. Description of the Related Art Generally, when welding an abutting portion of steel pipes from the outer peripheral surface side, a groove having a substantially V-shaped cross section is formed at the abutting portion. The cutting method is adopted. The light cutting method scans a light beam, for example, a laser beam in a manner of traversing the groove over the surface of the member to be welded on both sides of the groove, and images reflected light from the groove and the surface of the member to be welded, This is a method of measuring the groove shape based on the image.

In this light cutting method, a light beam is scanned across the groove, but if there is a gap at the root bottom of the groove, diffused reflection light from the edge portion becomes noise and the detection error becomes large. There was a problem. Therefore, in order to prevent the molten liquid from falling on the back side of the member to be welded, the backing metal provided in a state where the root bottom is closed is used to improve the detection accuracy of the groove shape.

FIG. 8 shows a groove 3 of the members 1 and 2 to be welded to each other.
FIG. Members to be welded 1 and 2
In order to close the root bottom of the groove 3 for one-sided penetration welding in, the backing metal W is fixed by spot welding or the like on the back surface side across the members to be welded 1, and the laser beam LB in this state. At, the scanning is performed in a direction traversing the groove, the reflected light image is captured, the groove shape is detected based on the captured image, and then welding is performed.

[0005]

However, in such a conventional method, it is difficult to bring the backing metal W and the members 1 and 2 to be welded into contact with each other over their entire facing surfaces in a surface contact state. Or, since the members to be welded 1 and 2 are curved, a gap d (about 0.5 mm) is often formed between them, which causes a problem that an accurate groove shape cannot be obtained.
The present invention has been made in view of the above circumstances, and its purpose is to be able to close the root bottom in a state of being in close contact with the member to be welded, and to significantly improve the groove shape detection accuracy by the optical cutting method. It is an object of the present invention to provide a welded portion inspection method that can be improved.

[0006]

According to a first aspect of the present invention, there is provided a method for inspecting a welded portion, which is a backside wave for closing a root bottom of a groove for one-sided penetration welding formed at opposing portions of members to be welded to each other. After forming a welding bead by welding or pasting a thin film on the back side of the member to be welded to close the root bottom, scan the light beam in the direction crossing the groove and capture the reflected light image from the groove. The groove shape is detected based on the captured image.

According to a second aspect of the present invention, there is provided a method for inspecting a welded part, in which a light beam is scanned in a direction traversing the groove while welding is being performed on the groove formed in the facing portions of the members to be welded to each other. It is characterized in that reflected light images from the groove and the welding bead are captured, and the welding bead shape is detected based on the captured image.

[0008]

In the first aspect of the invention, since the backside welding or the thin film is adhered in such a manner that the root bottom of the groove is closed,
The member to be welded and the welding bead or thin film are in close contact with each other and no gap is formed, so that the groove shape can be accurately detected by the optical cutting method. In the second aspect of the invention, by performing the light cutting method while performing the penetration welding to the groove, not only the groove shape but also the shape of the welding beat can be detected to obtain the desired welding bead shape. It is possible to precisely control the welding conditions.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments.

(Embodiment 1) FIG. 1 is a schematic cross-sectional view showing an implementation state of a welding portion inspection method according to the present invention.
Reference numeral 2 is a member to be welded, 3 is a groove, 4 is a welding bead formed by backside welding, 6 is a laser beam head, and 7 is a CCD camera. The members to be welded 1 and 2 to be welded to each other have their end faces opposed to each other at a predetermined interval, and a groove 3 for one-sided penetration welding is formed at the abutted ends. And the root bottom of this groove 3 has both welded members 1,
It is closed by a welding beat 4 formed by performing back-side welding in a manner straddling 2.

The laser beam head 6 and the CCD camera 7 are respectively disposed above and facing the groove 3, and the laser beam head 6 extends the groove 3 over the surfaces of the groove 3 and the members 1 and 2 to be welded on both sides thereof. Laser beam LB in the transverse direction
The groove 3 is scanned at, and the CCD camera 7 captures the reflected light image from the groove 3. A display unit 9 is connected to the CCD camera 7 with a signal processing unit 8 interposed therebetween, and the captured image is processed by the signal processing unit 8 and displayed on the display unit 9.

FIG. 2 is a schematic diagram showing a light-section image displayed on the display unit 9, where the horizontal axis indicates each position in the transverse direction of the groove 3 and the vertical axis indicates the position of the groove 3 in the height direction. Are shown respectively. Further, the signal processing unit 8 is a V-shaped groove upper end position Q which is a main point in judging the shape of the groove 3.
₁ (x ₁ , y ₁ ), Q ₂ (x ₂ , y ₂ ), lower end positions Q ₃ , Q ₄ and both corners of the root bottom Q ₅ (x ₅ , Y ₅ ), Q
The coordinate value of ₆ (x ₆ , Y ₆ ) is calculated and displayed on the screen of the display unit 9. As a result, the shape and size of the groove 3 can be detected accurately. After that, multiple-sided single-sided penetration welding (MAG welding) is performed under conditions that consider the groove shape and dimensions.

(Embodiment 2) FIG. 3 is a schematic sectional view showing another embodiment of the present invention. In the second embodiment, the thin film 5 is attached to the back surfaces of the members 1 and 2 to be welded so as to close the root bottoms of the groove 3 of the members 1 and 2 to be welded. As the thin film 5, the same material as or a material close to that of the members to be welded 1 and 2 is used, and a strip-shaped material having a thickness of about 25 to 50 μm is used. Usually, it is desirable to use an amorphous metal thin film in the form of a strip. In addition, a synthetic resin adhesive may be used for the attachment. When such a thin film 5 is used, when the penetration welding is performed from the groove 3 side, it is instantly melted and solidified as it is as a part of the weld metal.

(Embodiment 3) FIG. 4 is an explanatory view showing still another embodiment of the present invention. In this third embodiment, FIG.
As shown in (a), the root bottoms of the groove 3 of the members 1 and 2 to be welded are closed by a weld bead 4 by backside welding, and then the shape inspection of the groove 3 is performed in the same manner as in Example 1, and thereafter. ,
While performing penetration welding with a welding torch (not shown),
Bevel 3 using laser beam head 6 and CCD camera 7
Also, the reflected light from the welding bead 10 is imaged, and the shape of the welding bead 10 is detected based on the captured image.

The CCD camera 7 receives signals as in the first embodiment.
The processing unit 8 and the display unit 9 are connected, and a CCD camera
An image as shown in Fig. 4 (b) is taken at 7 and this is signaled.
An image as shown in Fig. 4 (c) is obtained by passing it through the processing unit 8.
It For such an image, a V-shaped
Top Q of eggplant groove 3₁, Q ₂And weld bead 10 and groove 3
Intersection Q with₇, Q₈Calculate the coordinates of the
The shape of the bead 10 is detected. And the detected welding bee
Welding conditions such as welding current, welding
The ear supply speed, the amount of inert gas supply, other welding speed, etc.
We will carry out welding by performing feedforward control
And

(Embodiment 4) FIG. 5 is a schematic view showing still another embodiment of the present invention. In this Embodiment 4, the present invention is applied to a pipe welding step in pipe laying work. . In the figure, P _{1 to} P ₇ are all tubes. The pipe P ₆ is already welded at one end thereof, and the pipes P _{1 to} P ₅ are already welded at both ends thereof to the other pipes, respectively. An inner clamping device 13 is arranged at the end of the pipe P ₆ to which the pipe P ₇ is to be welded, to which the pipe P ₇ is connected.

The pipe P ₇ is connected to one end of the pipe P _{6 in such} a manner that the pipe 12 is fitted onto the inner clamp device 13 by the crane 12 with the coating portion 11 formed on most of the intermediate portion except both ends thereof. After being abutted against each other and clamped on the inner surface by the inner surface clamping device 13 so as to be aligned with the pipe P ₆ , inner surface welding is performed by the inner surface welding machine 14 provided in the inner surface clamping device 13 As in Example 1, the weld bead 4 is formed and the root bottom of the groove 3 is closed.

Between the pipes P ₆ and P _5, which have already finished the inner surface welding, the outer surface welding machine 15 performs welding on the groove 3 on the outer surface. The X-ray inspection device 16 detects flaws between the pipes P ₅ and P ₄ which have finished the outer surface welding, and further, an automatic ultrasonic flaw detector 17 detects flaws between the pipes P ₄ and P ₃ . The connecting portion between the pipes P ₃ and P ₂ after the flaw detection is covered by an automatic coating device 19 suspended by a crane 18 and extends between the coating portions 11 and 11 of the pipes P ₂ and P _1. Thus, the coating layer 20 is formed and the connection work is completed.

FIG. 6 shows an inner surface clamping device 13 and an inner surface welding machine.
FIG. 14 is an enlarged side view showing 14. In FIG. 6, 21 is a frame of the clamp device main body, and 22 and 23 are left and right hydraulic cylinders. The clamp device main body frame 21 is formed in a cylindrical shape with a thick center portion and thin end portions, and a disk-shaped collar portion 24, 24 is provided on the outer periphery of the thick-walled cylindrical portion 21a. The thin cylindrical portion 21b is provided with a space of
It is designed to function as a guide tube for the 22b. Between the positions of the flanges 24, 24 near the outer peripheral edge and the cylinder cases 22a, 23a of the hydraulic cylinders 22, 23, the connecting arms 25 are passed at a plurality of positions (usually 8 positions) in the circumferential direction to provide a clamping device. The body frame 21 and the hydraulic cylinders 22 and 23 are positioned and fixed on substantially the same straight line.

The guide 25a of each cylindrical in connecting portion of each connecting arm 25 for the flanges 24, 24 are provided outwardly, each guide 25a shoe 26 is the pipe P _7, P ₆ It is slidably fitted to the inner peripheral surface of the so as to be able to come into contact with and separate from it. One end of a link 27 is pivotally connected to the inner end of each shoe 26,
The other ends are pivotally connected to the tips of the piston parts 22b, 23b of the hydraulic cylinders 22, 23. Each of the hydraulic cylinders 22 and 23 is configured by slidably fitting the same cylindrical piston parts 22b and 23b in the cylindrical cylinder cases 22a and 23a, and one end of the cylinders 22a and 23a is located on one end side. Protruding from the cylindrical portion 21 of the clamp device body frame 21.
They are externally fitted to b and 21b, and at the parts externally fitted to the cylindrical portions 21b and 21b, they are pivotally connected to the inner end of the shoe 26 via links 27, respectively.

Collars 22c and 23c are provided on the outer circumferences of the piston portions 22b and 23b.
When the piston parts 22b, 23b are slidably fitted in the cylinder cases 22a, 23a, oil chambers are formed on both sides of the collars 22c, 23c, and pressure oil is supplied to each one of the oil chambers. The pipes 28,28 are connected. 31 and 32 are push springs for pushing back the piston portions 22b and 23b from the inner clamp device body frame 21 side, and 33 are wheels provided on the plurality of connecting arms 25 and are provided at a plurality of circumferential positions. The inner surface clamp device 13 is movably supported by the wheels 33 on the inner peripheral surfaces of the pipes P ₇ and P ₆ .

On the other hand, one collar portion is provided in the middle of the collar portions 24, 24.
Located near 24, a rotating disk 34 is pivotally supported.
The welding torch 35 and the pipe that make up the inner welder 14
P₇, P ₆The height sensor SE that detects the height to the inner surface is the husband
It is provided to be movable and adjustable in the radial direction of the rotating disk 34.
ing. The rotating disk 34 has a gear 34a near its inner circumference on one side.
It is provided inside the inner frame 21 of the inner clamp device.
The output shaft of the motor M installed in the
It has been linked together.

Next, the operation of such an inner surface clamping device 13 will be described. In the mode as shown in FIG. 5, the inner surface clamp device 13 is moved and positioned so that the left half of the pipe P ₆ is projected outward from one end portion of the pipe P ₆ , and in this state, the pipe P ₇ is externally fitted to the inner surface clamp device 13. In this manner, it faces the end of the pipe P ₆ . It drives the hydraulic cylinders 22 and 23,
b, the shoes 26 via the link 27 when extruding a 23b is pushed radially outwards, is brought into pressure contact with the inner surface of the pipe P _7, P _6, the pipe P _7, P ₆ is positioned on the same straight line Fixed.

In this state, the motor M is driven and the rotating disc 34
And the height sensor SE and the welding torch 35 are rotated along the inner surfaces of the abutting ends of the pipes P ₇ and P ₆ , and the welding torch 35 and the height sensor SE are rotated around the inner periphery of the pipes P ₇ and P ₆ . the dimensions of the up tube P _7, inner P ₆ peripheral surface moves while detecting toward the surface side, stop the welding torch 35 as the size of the up tube P _7, inner P ₆ peripheral surface coincides with the target value at that position Then, MAG welding is performed on the abutting end as it is, and the weld bead 4 is formed in a manner of closing the root bottom of the groove in the same manner as shown in FIG.

FIG. 7 is a schematic side view of the outer surface welding machine 15.
In the figure, 41 is a guide rail, 42 is a moving carriage, and 43 is a welding truck.
A reference numeral 44 indicates a welded portion sensor. Guide rail 41
Is the pipe P _FivePositioning on the outer peripheral surface of the
Pipe 41a for contact with the pipe P_FiveLocated approximately concentric with
It is fixed so that it can be moved to this guide rail 41
42 is mounted so that it can move around, and it is
P_FiveIt is designed to rotate around.

A welding torch 43 is provided on the movable carriage 42 so as to face the groove 3 at the abutting portion of the pipes P ₅ and P ₆ , and at the position spaced apart from this by a predetermined distance in the circumferential direction. The weld sensor 44 is installed. The weld sensor 44 is composed of the laser beam head 6 and the CCD camera 7,
Immediately before the welding torch 43, the shape of the welding bead 10 previously applied in the same manner as that shown in Example 3 shown in FIG. 4 is detected,
Based on the detected shape data, MAG welding is performed while controlling welding conditions such as welding current, welding wire supply rate, inert gas supply rate, and other welding speeds. The manner of detecting the weld bead shape by the laser beam head 6 and the CCD camera 7 is substantially the same as that described in the third embodiment.

[0027]

As described above, according to the first aspect of the invention, the root bottom of the groove can be closed in surface contact with the back surface of the member to be welded, and the accuracy of the groove shape inspection is greatly improved. Welding quality can be improved. Further, in the second invention, the weld bead shape as well as the groove shape can be detected, so that the welding condition can be precisely controlled to obtain the desired weld bead shape, and similarly, the welding quality can be improved. It will be possible.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an implementation state of a welded portion inspection method according to the present invention.

FIG. 2 is an explanatory diagram showing an image on the display unit obtained in FIG.

FIG. 3 is a schematic cross-sectional view showing another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing still another embodiment of the present invention.

FIG. 5 is a schematic diagram when the welding portion inspection method according to the present invention is applied to a pipe connecting step.

FIG. 6 is an enlarged side view of the inner surface clamping device and the inner surface welding machine used in FIG.

FIG. 7 is an enlarged side view of the outer surface welding machine used in FIG.

FIG. 8 is an explanatory diagram of a conventional method.

[Explanation of symbols]

 1, 2 Materials to be welded 3 Bevel 4 Weld bead 5 Thin film 6 Laser beam head 7 CCD camera 8 Signal processing unit 9 Display unit 21 Inner surface clamp device body frame 21a, 21b Cylindrical part 22,23 Hydraulic cylinder 24 Collar part 25 Connection arm 26 shoe 27 link 31 push spring 33 wheel 41 guide rail 42 moving carriage 43 welding torch 44 weld sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location B23K 9/127 508 E 7920-4E (72) Inventor Tatsuya Kasaya 2 Dejima Nishimachi, Sakai City, Osaka Sumitomo Inside Metal Plantech Co., Ltd.

Claims (2)

[Claims] 1. A weld bead is formed by backside welding to close a root bottom of a groove for one-sided penetration welding formed at opposing portions of members to be welded to each other, or to close the root bottom. A thin film is attached to the back side of the member to be welded, a light beam is scanned in a direction that traverses the groove, a reflected light image from the groove is captured, and the shape of the groove is detected based on this captured image. Weld inspection method. 2. A reflected light image from the groove and the welding bead, by scanning the groove formed in the facing portions of the members to be welded to each other with a light beam in a direction traversing the groove while performing welding. Is detected, and the weld bead shape is detected based on the captured image.