WO2014023512A1

WO2014023512A1 - Method for narrow-gap welding, welding system, welding part, and device

Info

Publication number: WO2014023512A1
Application number: PCT/EP2013/064787
Authority: WO
Inventors: Henning Hanebuth; Christian Werner
Original assignee: Siemens Aktiengesellschaft
Priority date: 2012-08-10
Filing date: 2013-07-12
Publication date: 2014-02-13
Also published as: DE102012214246A1; CN205085520U

Abstract

The invention relates to a method for narrow-gap welding using a welding electrode (10) in a narrow gap (15). An image (44) of the welding electrode (10) and/or of the arc and at least one wall (20, 25) of the narrow gap (15) are at least partly detected. The distance from the welding electrode (10) to the wall (20, 25) of the narrow gap (15) is ascertained using the image (44), and the position of the welding electrode (10) is adjusted dependent on the ascertained distance.

Description

description

Method for narrow gap welding, welding system, welding part and device

The invention relates to a method for narrow gap welding, a welding system, a welded part and a device.

In automated and fully mechanized tungsten inert gas narrow gap welding (TIG narrow gap welding), a pendulum welding electrode is used regularly. This oscillating welding electrode is performed in narrow gap welding in ei ^¬ nem narrow gap. It is necessary, the welding ^¬ electrode and / or to electrode forming when welding with the welding arc precisely at the respective seam edge, that is, one of the two lateral, the narrow gap bounding walls of Engspalts along feels younger ^¬ reindeer, to get a well-defined penetration into the weld ^¬ flank. Penetration depth and penetration resistance are decisive for seam quality and process reliability in narrow gap welding.

It is known to monitor the current or time-averaged alignment or position of the welding electrode relative to the walls of the narrow gap by means of a camera image by the welding personnel and required ^¬ if nachstellt. Alternatively and likewise known, current and voltage signals are evaluated when the welding electrode approaches the seam flanks. This go forward but is inaccurate due to signal noise and other interference effects and requires two complicated calculation ^¬ routines.

It is therefore an object of the invention to provide a comparison with the prior art improved method for narrow gap welding by means of a welding electrode in a narrow gap bereitzustel ^¬ sources. In particular, in the method, a control and an adjustment of the distance of the welding electrode of the Wall of the narrow gap with high reliability allows. It is another object of the invention to provide a welding system for carrying out this method and to provide a welded part and a device, which have an improved quality tat to create.

This object is achieved by a method having the features specified in claim 1, with a welding system having the features specified in claim 8, a welded part with the features specified in claim 9 and with a device having the features specified in claim 11. Preferred developments of the invention are described in the appended subclaims, the following description and the

Drawing indicated.

In the method according to the invention for narrow-gap welding by means of a welding electrode in a narrow gap, an image of the welding electrode and / or an arc forming at narrow gap welding and at least one wall of the narrow gap is at least partially detected during narrow gap welding, based on the image of the distance of the welding electrode determined the wall of the narrow gap and depending on the ermit ^¬ teten distance the position / a deflection of Schweißelekt ^¬ rode provided. In particular, a deflection of the welding electrode is understood to mean a pendulum deflection of a pendulum electrode.

In particular, the determination of the distance of the welding electrode is processor-based from the wall of Engspalts from the image by means of an automatic Bildauswerteverfahrens, insbeson ^¬ particular carried out. The process by fiction, contemporary ^¬ is a strict control of

Flank burn-in possible. Such a well-defined edge penetration of the arc in the seam edge reduces fusion defects and required rework and Nebenzei ^¬ th and significantly reduced processing times. The production safety and manufacturing quality are increased interpreting ^¬ Lich. Appropriately, in the method according to the invention, the distance of the welding electrode is not determined solely by a wall of the narrow gap, but the distance of the welding electrode in each case from two gegenüberlie ^¬ ing walls of the narrow gap determined continuously. Is Conveniently, / is the position of the welding electrode thereby ^¬ provides such ge that if the distance between the welding electrode of each ^¬ weils a wall of the Engspalts falls below a threshold value / Schwellabstand, the distance of the welding ^¬ electrode of said wall immediately or in time average over several oscillations is increased. Appropriately, the distance of the welding electrode of each of both of the two opposite walls is monitored and in each case drops below a threshold value corresponding to ge ^¬ represents. Preferably, the mean time position and / or the center position and / or the current deflection of the welding electrode is set depending on the determined. In an expedient development remain about the deflections of the welding electrode from the determined distance of

Welding electrode independent of the wall of the narrow gap, while ^¬ while the temporal and / or spatial center position during several pendulum periods of the oscillating Schweißelekt- rode is made dependent on the smallest determined distance.

In a preferred embodiment of the method according to the invention, the image of the welding electrode and / or the

Arc and the at least one wall of the narrow gap spectrally ^¬ filtered filtered. In this way, the which forms the narrow gap welding arc pulls out or partially hide, so in intensity from ^¬ weaken, so that the image is not overexposed. Thus, enough light can be gathered to obtain / capture an image of a sharply delineated contour of the welding electrode and / or the at least one wall and / or the arc of the narrow gap. The welding electrode and / or the at least one wall of the gap Eng ^¬ are preferably illuminated by at least one laser and / or at least egg ner high power lamp in the inventive method. In this way genü ^¬ quietly light can be collected to obtain an image of a sharply delimiting contour of the welding electrode and / or the at least one wall of the Engspalts / capture. Ideal ^¬ typically exhibit at least a high-power lamp and / or the at least one laser has a spectrum such that a majority of the illuminating light is received even when spectrally-filtered ge ^¬ acquisition of the image in this. In this way, the image can be spectrally filtered at the same time capture and improve the detection of the image of the welding electrode due to the illumination.

Alternatively, and the intensity from at least areas of the spectrum ^¬ realm of originating from the arc light for illumination of the welding electrode and / or the wall / walls of the Engspalts is also preferable in the erfindungsge ^¬ MAESSEN method used. Conveniently, the image of the welding ^¬ electrode is thereby detected as spectrally filtered such that the predominant over ^¬ of the radiated from the arc, in particular visible light is so strong hidden, that the image is not overexposed, but at the same time the wall / walls and the welding electrode be detected with sufficient quality / intensity.

The method according to the invention is particularly preferably carried out when welding with a tungsten electrode, in particular during tungsten inert gas welding (TIG welding). Especially in TIG narrow gap welding, the weld depths are often between 50 to 220 mm with gap widths between 10 and 14 mm. In this case in particular, reworking of defective welded joints is extremely complicated or even even impossible because the welded joint is restrictedly accessible. Advantageously, the process according to the invention during welding at least a portion of a turbine and / or turbines ^¬ rotor and / or rotor and / or a shaft or the aforementioned components having component is performed. In particular, in the above-mentioned components, the interpreting ^¬ Lich increased process reliability leads to a significant cost saving in the manufacture of these components.

The welding system according to the invention comprises at least one welding electrode, particularly adapted for narrow gap welding ^¬ and preferably in the form of a tungsten electrode, at least one camera which is designed to detect the image of the welding electrode and an off ^¬ values means which of for determining the distance of the welding electrode a wall of a narrow gap is formed on the basis of the image captured by the camera, and an adjusting device, which is designed to position the position, in particular the temporally and / or spatially middle position, of the welding electrode. Expediently, the welding electrode is known by means of current or voltage signals as per se with oscillating welding electrodes,

adjustable.

Suitably, the welding system according to the invention comprises a high-power lamp and / or a laser and / or a

Spectral filter. Conveniently, a high-power lamp or a laser and a spectral filter are provided, wherein the spectral filter is selected such that it passes the light of the high-power lamp and / or the laser.

Suitably, the spectral filter is designed to at least partially attenuate or mask out the light of the arc that forms during welding.

The welding part welded according to the invention is welded with a method for welding with at least one welding electrode, as described above, and / or with a welding system according to the invention as described above. In particular, the welding part is at least a part a turbine and / or a turbine rotor and / or a rotor and / or a shaft. The welded part according to the invention can be manufactured as described above with particularly good quality.

The device according to the invention comprises at least one erfin ^¬ according to the welding part. The device ^{according to} the invention is particularly preferred or comprises a turbine and / or a turbine rotor and / or a rotor and / or a shaft.

The invention will be explained in more detail with reference to an embodiment shown in the drawing. The sole drawing figure 1 shows schematically a welding system for carrying out the method according to the invention for narrow gap welding by means of a welding electrode in a narrow gap in an arrangement for welding a welding part according to the invention of a device according to the invention.

The welding system shown in Figure 1 is used to carry out the method according to the invention for narrow gap welding by means of a welding electrode in a narrow gap. Further, a ^¬ OF INVENTION dung device according to the invention with a weld portion is manufactured by means of the process described below the bottleneck gap welding according to the invention by means of a Schweißsys ^¬ tems with a welding electrode in a narrow gap. In the method is welded to a workpiece 5 by means of a swinging TIG welding electrode (tungsten inert gas welding electrode) 10 in a narrow gap 15. In this case, the TIG welding electrode 10 oscillates between two lateral walls 20, 25 of the narrow gap 15 back and forth.

A high-power lamp 30 illuminates the TIG welding electrode 10 as well as the walls 20, 25. In further exemplary embodiments, which are not specifically illustrated, instead of a High-intensity lamp 30 may be a laser or it may be the intensity of a spectral range of the light originating from the arc to illuminate the TIG welding electrode 10 and the walls 20, 25 of the narrow gap 15 are used.

An image 44 of the TIG welding electrode 10 and the walls 20, 25 of the narrow gap 15 is detected by a camera 35. Zvi ^¬ rule camera 35 and the TIG-welding electrode 10 and the Be ^¬ tenwänden 20, 25 of the Engspalts 15 is a spectral filter 40 is provided which attenuates the abge ^¬ radiated by the developing during the welding by the TIG welding electrode 10 arc light significantly. The originating from the high Leis ^¬ tung lamp 30, reflected from the walls 20, 25 and the TIG welding electrode 10, however, light is almost all transmitted through. The camera 35 thus captures single ^¬ Lich the TIG welding electrode 10 and the side walls 20, 25, while on the other hand, the arc is not or hardly captured by the camera 35th The captured by the camera 35 image 44 is passed to an evaluation ^¬ device 45, which is formed based on the processor-based soft ^¬ ware of the image 44 evaluation. Since ^¬ at will by means of the evaluation means 45 of the distance of the TIG welding electrode 10 of a respective 25 of the walls 20, 25 of the Engspalts 15 by means of an image processing routine (not explained in detail here) is determined.

Depending on the distance determined by the evaluation device 45, the position of the TIG welding electrode 10 is set. In the present example, the position of the TIG welding electrode 10 remains unaffected, provided that the distance of the TIG welding electrode 10 from the wall 25 of the narrow gap 15 does not fall below a predetermined threshold value. However, when the distance falls below a predetermined threshold value, the TIG electrode 10 is spaced by means of a (not ex ^¬ plicitly shown) actuator means from the wall 25th For this purpose, the adjusting device transmits a current and / or a voltage signal to a TIG welding head 50, which dependent on this current and voltage signal or the deflection and / or (temporal or spatial) Mittenpo ^¬ sition of the TIG welding electrode 10 controls. The workpiece 5 is part of an inventive Turbi ^¬ nenläufers a turbine according to the invention. In further non-illustrated embodiments, the workpiece is part of a rotor according to the invention and / or a shaft according to the invention. It is understood that the camera 35, TIG welding electrode 10, evaluation device 45 and the adjusting device, optionally extended by the high-power lamp 30 and / or a La ^¬ ser and the spectral filter 40, an inventive

Form welding system.

Claims

claims

1. Method for narrow gap welding by means of a welding electrode (10) in a narrow gap (15),

in which an image of the welding electrode (10) and / or an arc formed during welding and at least one wall (20, 25) of the narrow gap (15) is at least partially detected, the distance of the weld from the image (44) ^¬ electrode (10) of the wall (20, 25) of the narrow gap (15) is determined and depending on the determined distance, the Po ^¬ position and / or a deflection of the welding electrode (10) ge ^¬ provides.

2. Method according to the preceding claim,

in which an evaluation device is used, which is designed to determine the distance of the welding electrode (10) on the basis of the image (44).

3. The method according to any one of the preceding claims, wherein the image (44) is detected spectrally filtered.

4. The method according to any one of the preceding claims, wherein the image (44) is detected spectrally filtered so that welding electrode (10) and / or arc and / or wall (20, 25) of the narrow gap (15) are filtered.

5. The method according to any one of the preceding claims, wherein the welding electrode and / or the wall of narrow gap are illuminated.

6. The method according to any one of the preceding claims, wherein the welding electrode (10) and / or the wall (20, 25) of the narrow gap (15) with at least one laser and / or at least ^¬ one high-intensity lamp (30) is illuminated.

7. The method according to any one of the preceding claims, wherein a camera (35) with an optical axis paral ^¬ lel to the local longitudinal course of the narrow gap (15) on the Welding electrode (10) is aligned, in particular for Er ^¬ version of the image (44).

8. Welding system adapted for carrying out a method of welding according to one of the preceding claims, comprising at least one welding electrode (10), a camera (35) which detects an image (44) of the welding electrode (10) and / or the arc and / or at least part of a wall (20, 25) of the narrow gap (15) is formed, an evaluation device (45), which for determining the distance of the welding electrode (10) from the wall (20, 25) of the narrow gap (15) the image (44) of the camera (35) is formed, and an adjusting device, which is designed to position the position of the welding electrode (10) depending on the determined distance.

Welded part welded with a welding method according to one of the preceding claims and / or with a welding system according to the preceding claim.

10. Welding part according to one of the preceding claims, which is at least part of a turbine and / or a Tur ^¬ binenläufers and / or a rotor and / or a shaft.

11. Device comprising at least one welded part according to ei ^¬ nem of the preceding claims.

Device according to the preceding claim, which is or comprises a turbine and / or a turbine rotor and / or a rotor and / or a shaft.