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2021 №10 (04) DOI of Article
10.37434/as2021.10.05
2021 №10 (06)

Automatic Welding 2021 #10
Avtomaticheskaya Svarka (Automatic Welding), #10, 2021, pp. 35-39

Electroslag technologies for repair of through-thickness cracks in thick parts

S.M. Kozulin1, I.I. Lychko1, H.S. Podyma2
1E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: office@paton.kiev.ua
2NTUU «Igor Sikorskiy Kyiv Polytechnic Institute». 6/2 Dashavska Str., 03056, Kyiv, E-mail: meganom8@ukr.net

Results of investigations are presented, which were performed in order to develop a highly-productive technology for repair of through-thickness cracks in thick parts in their operation site. The objective of the work is to study and establish the main principles of a high-efficient technology of repairing defects of the type of through-thickness cracks in thick parts in their operation site by the method of consumable nozzle multipass electroslag welding. The main tasks of the study were selection of principal diagram of electroslag welding, development of a procedure for calculation of geometrical parameters of edge preparation, that the most fully meet the conditions for formation of sound metal of the welded joint in a wide gap, development of basic principles of the technique of making the welds, and creation of routing technology of repair. Performed studies were the base for development of decision taking algorithms and general principles of the technology for repair of large-sized parts of unique equipment in its operation site, using the proposed method. Technological recommendations for repair of throughthickness cracks in such parts are based on the following postulates, formulated proceeding from the features of the proposed method: domain of rational values of welding specific energy, ensuring sound weld formation, techniques allowing hot crack prevention in the weld central parts, conditions of minimizing the welding stresses when welding rigid joints, conditions of controlling the weld chemical composition that provide reduction of the fraction of base metal participation in weld formation, and lowering of harmful impurity level in it, and recommendations on selection of electrode and accessory materials, etc. Technological recommendations were successfully tried out in six cement works at repair of though-thickness cracks in the rotary kiln bands. 15 Ref., 5 Fig.
Keywords: multipass electroslag welding, consumable nozzle, through-thickness cracks, repair, specific heat input, hot cracks, welding voltages, decision taking algorithm, technology recommendations


Received: 28.07.2021

References

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