2019, vol. 64, br. 2, str. 73-82
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Nove visoko produktivne tehnologije kombinovanog zavarivanja glavnih cevovoda velikog prečnika
New highly productive technology of combined welding of main pipelines of major diameter
Russian Union Of Oil And Gas Constructors, Russia
Ključne reči: magistralni gasovodi; zavarivanje; visokoproduktivne tehnologije
Keywords: main gaspipelines; welding; highproductive technologies
Sažetak
U toku izgradnje cevovoda, zavarivanje kružnih nerotirajućíh spojeva cevi je jedna od glavnih radnih operacija. Ova operacija se izvodi različitim metodama. Tehnologija zavarivanja svake metode ima posebne karakteristike koje je čine privlačnom za korišćenje na jednom ili drugom objektu u zavisnosti od specifičnih uslova građevinskih radova. U međuvremenu, unapređenje poznatih i razvoj novih, univerzalnijih tehnologija zavarivanja, važan je zadatak izgradnje cevovoda. Hitni karakter ovih radova, raste s obzirom na predloženu izgradnju glavnih cevovoda sa visokim radnim pritiskom i debljinom zida od 30 mm i više za cevi velikog prečnika. Istovremeno, zahtevi za pouzdanošću se uveliko povećavaju. U takvim okolnostima, efikasnost zavarivanja može se odobriti samo uz upotrebu visoko produktivnih automatskih metoda zavarivanja koje osiguravaju visok kvalitet zavarenih spojeva. Svrha ovog rada je razvoj visokoproduktivne tehnologije automatskog zavarivanja nerotirajuíh spojeva na glavnim cevovodima velikog prečnika sa povećanom debljinom zidova cevi za transport gasa i nafte. Tehnologija osigurava visok kvalitet zavarenih spojeva. Analizom različitih aspekata poznatih automatskih metoda zavarivanja cevi, omogućeno je odrediti smer u kojem se zadatak može rešiti. Za to je optimalna bila kombinovana metoda zavarivanja, uključujući pritisak i elektrolučno zavarivanje. Kao rezultat toga preporučujemo novi način automatskog zavarivanja. Sastoji se od dve široko testirane metode zavarivanja: sučeono zavarivanje varničenjem (FBW) i zavarivanja samosaštitnom punjenom žicom uz pomoć prisilnog oblikovanja šava (SFCAW). Kombinovanjem ovih metoda zavarivanja postignut je pozitivan efekat koji je teško ostvariti korišćenjem svake od ovih metoda, odvojeno. To je omogućilo, kao što će biti prikazano kasnije, da poboljša zavarene spojeve i poveća efikasnost zavarivanja. Slika 1 prikazuje makropresek šava cevi zavarene predloženim postupkom.
Abstract
In the course of construction of the pipelines, welding of circular nonrotative pipe joints is one of the main working operations. This operation is carried out using different methods. The welding technology of each method has special features which make it attractive for using at one or another facility depending on specific conditions of the construction work. Meanwhile, improvement of the well-known and development of new, more universal technologies of welding, is an important task of the pipeline construction. The urgent character of this work grows increasing in view of proposed construction of major pipelines with a high work pressure and the wall thickness of 30 mm and more for pipes of big diameter. At the same time the requirements to reliability are increasing greatly. In these circumstances the effectiveness of welding may be approved only by using highly productive automatic methods of welding which ensure welded joints of high quality. The purpose of this work is development of highly productive technology of automatic welding of nonrotative joints at the main pipelines of big diameter with increased thickness of pipe walls for gas and oil transportation. The technology ensures welded joints of high quality. The analysis of different aspects of the well-known automatic methods of pipe welding has allowed to determine the direction in which the task can be resolved. To do it the combined method of welding including press and arc welding turned out to be the most optimum one. As a result we recommend a new method of automatic pipe welding. It consists of two welding methods widely tested in practice: flash-butt welding (FBW) and self-shielded fluxcored arc welding by forced formation of weld (SFCAW). By combining these methods of welding a positive effect has been achieved which was difficult to achieve by using each of these methods apart. It has allowed, as it will be shown later, to refine the welded joints and to increase the efficiency of welding. The Figure 1 shows a macrosection of a pipe weld executed by using the proposed method.
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