RU2139780C1 - Laser complex for main pipeline laying - Google Patents

Abstract

FIELD: laser welding, applicable for laying of main pipelines of various purpose in field conditions, especially in northern regions. SUBSTANCE: the complex comprises a travelling device, platform carrying an independent electric power plant, control equipment, process laser, auxiliary equipment, external beam guide, beam guide magazine with pipes intended for welding and having a drive of its own, device for tightening the pipe to the pipeline, supports for attachment and alignment of the pipeline. Provision is also made for another process laser for welding of circumferential seam from the outside. In combination with the available complex equipment a two-sided laser welding is provided. The inside root seam is the first to be penetrated and then the outside one. EFFECT: enhanced quality of welded joint, provision for joining of pipes of larger thicknesses. 4 cl, 4 dwg

Description

 The present invention relates to the field of laser welding and can be used for laying main pipelines for various purposes in the field, especially in the northern regions.

 A known installation for laser welding of pipelines [1]. The installation is a tube-covering structure, which includes a drive and a mechanism for moving it along the pipe, a technological laser with a focusing lens and a drive for their rotation around the pipe. Power supply and control of the installation is carried out from an autonomous complex moving along the ground with the installation next to the pipe. The connection between the installation and the complex is provided by the communications supply unit.

 Installation works as follows. The pipe intended for welding is butt-joined to the butt-end of the end of the pipeline. Further, the installation, using its own drive and movement mechanism, moves along the end of the pipeline to the junction. The focusing lens mounts exactly opposite the joint. The laser turns on and at the same time the laser rotation drive with the focusing lens is turned on. Thus, welding of the annular seam is carried out. After the welding process, the laser is turned off and the installation, together with the autonomous complex, moves to the next joint. After this, the technological cycle is repeated.

 A known installation for laser welding of pipelines [2]. The installation includes a mobile device, a platform with a technological laser placed on it, control equipment, a power plant, and auxiliary equipment. It also includes a beam line store with pipes designed for welding located on them and a device for clamping the pipe to the pipeline.

 Installation works as follows. A store with beam lines and pipes intended for welding leads the end of one pipe to the end face of the end fixed in the clamps of the pipeline.

 Using the preload device, the pipe is pressed to the end of the pipeline. After that, the laser is turned on and the radiation through the beam line is fed to the rotary mirror. Then it is fed to the focusing lens and then to the welded joint. After welding the annular seam, the installation moves forward along the pipeline route at a distance equal to the length of the pipe. The beam path store supplies a new pipe with its beam path to the weld zone and the process cycle repeats.

 A common drawback of the above-described installations is a one-sided method of welding an annular seam - in the first case - external, in the second case internal. The result of this is a poor-quality welded joint due to the presence of large concentrations of stress and strain, cracks, and also defects in the form of inclusions in the root of the weld.

 All this can lead to the destruction of the welded joint and, consequently, to failure of the pipeline with large material losses.

 In addition, a one-way welding method allows welding of pipes of a certain, limited thickness. And now there is a steady trend towards the use of pipelines of increasing working pressures and, consequently, the use of pipes of large thicknesses.

 It is known that there is a two-way laser welding method [3]. This method allows for the formation of welds of a favorable configuration, which significantly reduces all of the above defects.

 The problems solved by the invention are to improve the quality of the welded seams of the beam lines while increasing the productivity of the welding complex.

 The above problems are solved by the fact that in the laser complex for laying the main pipelines, which includes a mobile device, a platform with an autonomous power station placed on it, control equipment, a laser, auxiliary equipment, an external beam path, a beam path store with tubes intended for welding and placed on them and having own drive, device for pressing the pipe to the pipeline, supports with the end of the pipeline fixed in them, at the junction of the pipe end with the end th pipeline from the outside is an additional laser having a rotary drive around the joint. Between the lens located on the beam line (inside the pipe) and the external lens relative to the axis of the pipe there is an angle determined by the technological conditions.

 The power of the additional laser can be equal to or significantly greater than the power of the laser, which provides welding of the internal root seam. It is known that it is the defects in the root of the seam that determine the strength of the entire welded joint, so the inner seam should be made as defectless as possible. It is known that the number of defects in the weld, as well as tensile stresses in the heat-affected zone of the thermal influence, decrease with increasing welding speed. Therefore, it is important to ensure the maximum possible welding speed of the inner seam, even due to the penetration depth, by boiling the remaining large part of the pipe wall thickness at a lower speed with an external additional laser. In order to increase the productivity of the process, you can cook the external seam with several beams at once. For this, an additional laser must be multi-beam, equipped with an appropriate number of focusing lenses oriented along the radii relative to the axis of the pipeline and equally spaced relative to each other in angle.

 The complex is as follows (Fig. 1). A platform 2 is attached to the mobile device 1, on which are located an autonomous power station 3, control equipment 4, auxiliary equipment 5 (gas facilities), a process laser 6. Radiation is extracted from the process laser using an external beam path 7. A store of 8 beam paths 9 s is located on the platform the pipes 10 intended for welding are placed on it. The store has a displacement drive 11 and a device for pressing the pipe to the pipe 12. At the end of each beam path there is a mechanism and displacement drive along the axis of the pipe 13 (Fig. 2 and Fig. 3), a pivoting mirror 14 and a focusing lens 15, and a lens rotation drive around the axis of the pipe 16. An external lens 17 is rigidly connected to the laser at the junction of the pipe with the pipeline from the outside 19, having a rotation drive around the pipe 18. Laser 19 delivers radiation to the lens 17.

 On the platform are placed supports 20 that hold and simultaneously center the end of the pipe 21.

 The complex works as follows. A mobile device 1 moves along a pre-laid route of the future pipeline along with a platform 2. The autonomous power station 3, control equipment of the complex 4, auxiliary equipment 5 are placed on the platform in front of it. The radiation generated by the process laser 6 is directed through an external beam path 7 having rotary mirrors. Then the radiation enters the beam path 9 and, being transported along it to the rotary mirror 14, reflected from which, is sent to the focusing lens 15. In it, the radiation is focused and directed directly to the junction. The rotation of the focusing lens together with the rotary mirror is provided by the actuator 16 around the axis of the welded pipes. At the same time, the root seam is boiled. Welding with an external focusing lens 17 is carried out at a certain distance from the welding spot of the lens 15 (Fig. 4) (angle α). Simultaneous welding of internal and external seams is also possible, in this case α = 0. The focusing lens 17 receives radiation from the process laser 19, which has a rotation drive 18 around the pipe. The formation of the outer weld occurs on the hot inner. After two-sided welding of the annular seam is carried out, the displacement drive 13 focuses the lens and the pivoting mirror to the right, thereby reducing the length of the beam path.

 The complex moves forward along the highway to the length of one pipe. Next, the beam duct store 8, using the drive 11, leads the new pipe 10 to be welded to the end of the pipe 20. The end of the pipe is supported and centered relative to the pipe being welded using supports 21. The device for compressing the pipe to the pipe 12 presses the pipe to the end of the pipe. The drive movement 13 of the focusing lens moves it to the left to the junction. After that, the technological cycle of the complex is repeated.

 The use of double-sided laser welding of bulky structures such as the end of the pipeline and the welded pipe with supports on a single platform allows them to be precisely centered with each other and, therefore, create favorable conditions for the formation of a weld.

 List of references.

 1. Patent of Russia N 2070494. "Installation for laser welding of pipelines." Bull. N35, dated 12.20.96.

 2. Russian patent N 2074798. "Installation for laser welding of pipelines." Bull. N7, dated 10.03.97. (prototype).

 3. A.A. Rybakov, V.V. Yakubovsky, V.Ch. Kiryan et al. A study of the operability of welded joints of 10G2BT pipe steel, performed by two-pass laser welding. Automatic welding, N 7, 1995, Kiev, pp. 12-17p

Claims (4)

 1. A laser complex for laying pipelines, including a mobile device and a platform with an autonomous power station, control equipment, a laser, auxiliary equipment, an external beam path, a beam path store with welded tubes and their own drive, a device for pressing the tube to the pipeline and supports for fixing the ends of the pipeline to them, and at the ends of each beam path, focusing lenses and rotary lenses are fixed Mirrors, characterized in that it is equipped with an additional focusing lens and an additional laser for welding an external weld, located between the beam line store and supports and made with the possibility of covering the end of the pipeline and the welded pipe and with the possibility of directing the output radiation into an additional focusing lens, moreover, an additional laser and the focusing lens is rotatable around the junction of the pipe and pipe.  2. The laser complex according to claim 1, characterized in that the additional focusing lens and each of the focusing lenses of the beam paths are installed at an angle with respect to each other.  3. The laser complex according to claim 1, characterized in that the additional laser is made with a power greater than the power of the technological laser.  4. The laser complex according to claim 3, characterized in that the additional laser is equipped with several focusing lenses to provide the possibility of obtaining output beams with a number greater than 1.

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