Main advantages of laser technolo-
gies in manufacturing of flat panels, comparing to conven-tional tech- niques, are: • increased in 1.5 – 3 times productivity; • low material (by 20.0-40.0%) and en- ergy consumption;
• minimum residual stresses and de- formations in welded structures. For manufacturing of complex-
AD VER TORIAL For welding of inner circular strap,
Aleksander N. Aleshkin, Valerii M. Levshakov, Natalia A. Steshenkova.
shaped welded structures, SSTC has designed a robotized complex for laser cutting and hybrid laser-arc welding in various positions (see Fig. 2). The sys- tem is equipped with quick-detachable processing heads, allowing to manu- facture 3D structures up to 10 m long at one position without moving and shifting. Use of such equipment gives up to 30% overall cost of hull con- struction and increase productivity by 10% with simultaneous reduction of welding deformations in 1.4 times, comparing to conventional arc weld- ing techniques. For welding of marine engineering
Shipbuilding and Shiprepair Tech-
articles, there is a program-controlled complex of robotized laser welding, intended for manufacturing of heat exchangers, and for welding in hard- to reach areas (see Fig. 3). Processing complex «Labyrinth» is intended for welding of thin-walled shells to mas- sive structures, e.g. in pumps or valves, and for welding-in thin-walled tubes into tube plates (in heat ex-changers). The system comprises 8 kW fiber laser, welding robot, laser head for welding in hard-to-reach places, or laser head with scanator for welding of tube grids. When scanator head is used, the
system operates as follows: ytterbium fiber laser generates nigh-concentrated beam, which is transferred through fib- er optic to optic head, where the beam is col-limated and passes through a system of controlled mirrors, mounted on the optical head, and then fo-cuses on the processed item. The mirrors al- low to scan the beam by two perpen- dicular axes in the plane on welding, and, accordingly, to track any com- plicated path in the area of laser beam operation (370х370 mm). The laser head is mounted on robotic manipu- lator, which positions the head above the processed item. The main task of such device is welding of tubes of vari- ous sections to a tube plate, and weld- ing of sockets in tubes to each other with through penetration. Minimal thickness of tube wall can be 0.5 mm and spacing between holes in the tube plate – 2 mm.
a
nology Center (SSTC), a leading design and technology ship-building center in Russia, since its foundation in 1939 has been developing and implement in Russia shipbuilding sector highly ef- fective technologies for construction, operation and repair of marine equip- ment. One of the methods for improv- ing quality of shipbuilding products is application of tech-nologies for processing of hull structures and ma- rine engineering articles, based on use of high-concentrated energy sources, such as laser and plasma technolo- gies. Main advantages of laser welding, comparing to conventional arc tech- niques, are higher processing speed, good quality of welds, minimal zone of thermal effect, minimum consump- tion of adding materials and practical absence of welding deformations. For manufacturing of flat panels,
one of main structural component of a ship’s hull, there is an industrial technology, based on laser cutting and hybrid laser-arc welding. The technol- ogy is imple-mented at a pilot line for assembly and welding of flat panels up to 12 x 12 m from plates 4 to 20 mm thick, developed and manufactured in cooperation with IMG, Germany (see Fig. 1), The innovative solution, ap- plied in the line for the first time in the world practice, is combination of grooving by laser cutting and joining of plates with laser-arc welding in one operational position.
there is a special optical head, which focuses laser beam perpendicular to inner surface of the item. Laser beam, after passing through optical connec- tor of laser output, comes to a collima- tor, secured in the upper part of head’s casing. From the collimator, the beam comes to focusing device in lower part of head extension, and, having passed through rotary mir-ror module and through protective glass, comes to processing (welding) zone. The main purpose of the device is welding-in of thin-walled component into a massive structure of outer shell, i.e. making a lap joint. The beam moves against the item either by rotation of item itself, or by moving rotary mirror module around the central axis of the weld seam (rotation of one of the units). Main advantages of the system, com- paring to its analogs:
Fig. 1 – Flat panels line Plates welding position is equipped а – Laser system Labyrinth
b – component of tube plate in a heat exchanger
with a pressing portal for securing plates, and portal for la-ser cutting and hybrid laser-arc welding of their butt edges, with two carriages with optical heads for cutting and weld- ing. Laser cutting carriage is equipped with optical head for cutting and module for inclining this head by 0 to 10 degrees, for grooving purpose. The welding carriage combines hybrid laser-arc and tandem welding head, allowing to perform single-run weld of materials up to 20 mm thick. The plates, after feeding and alignment, are fixed with hydraulic cylinders on pressing portal. Sequential grooving is made by laser cutting. From plates over 14 mm thick, grooving is made with nosing. After grooving the plates are joined without gaps and then hy- brid-laser-arc welding is per-formed at a speed of 1.0-2.5 m/min. The weld-
ing carriage is equipped with guiding and weld tracking system. For thicker plates groove is filled with tandem welding head. This, plates up to 20 mm thick can be welded in a single run. After joining plates, framing is fixed on them with hydraulic clamps, installed on framing securing and welding portal, Special back bend- ing device is used for compensat-ing possible welding deformations. Then framing is welded to the plate with hybrid laser-arc welding in a single run. Equipment is fully automates and operation is controlled by pro- grams, started from op-erator’s panels. Standard procedure of hybrid laser-
c- laser welding of circular weld seam
arc welding of plates up to 20 mm thick and framing with integrated grooving by laser cutting is approved by Russian Maritime Register of Shipping (Ap- proval Certificate No. 12.02754.314 от 06.08.2013)
ADVANCED TECHNOLOGIES IN RUSSIAN SHIPBUILDING
- Welding speed up to 20 m/min, en- suring high productivity;
- Thickness of materials, welded in a single run – 0.5 to 8 mm;
- Processing zone – 12 m; - Welding in hard-to reach zones, name- ly welding-in of thin-walled tubes or their parts into a massive structure. Development and implementation
of laser technologies allow to achieve a new level of effec-tiveness in manufac- turing various structures in shipbuild- ing and marine engineering sector. For more information you are wel- come to visit
www.sstc.spb.ru
JSC “Shipbuilding & Shiprepair Technology Center”
7, Promyshlennaya str., 198095, Saint Petersburg
Phone: +7 (812) 786-26-10 Fax: +7(812)786-04-59 E-mail:
inbox@sstc.spb.ru
Fig. 2 – Robotized complex for welding and cutting in various positions: (a) overall view, (b) process of hybrid laser-arc welding b
Fig. 3 – Laser processing complex Labyrinth
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