The Paton Welding Journal, 2014, №11



2014 №11 (02)

DOI of Article 10.15407/tpwj2014.11.03

2014 №11 (04)

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The Paton Welding Journal, 2014, #11, 15-23 pages  

CRACKING SUSCEPTIBILITY OF WELDED JOINTS IN REPAIR STRUCTURES ON MAIN GAS PIPELINES

V.S. BUT, S.Yu. MAKSIMOV and O.I. OLEJNIK

E.O. Paton Electric Welding Institute, NASU. 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
Repair of main pipelines under pressure involves application of various reinforcing welded structures. Operation periods of trunk lines in many cases are longer than 30 years, and pipe material can have an unfavourable structure, hence the need to broaden the concepts of ensuring the technological strength of welded joints under repair conditions. The work gives the results of studying the susceptibility of low-alloyed steel welded joints to cold and lamellar cracking. For this purpose, experiments were conducted on technological samples, simulating the real welded joints of repair structures. Positive impact of preheating, postweld heating and thermal annealing effect on cold cracking resistance is shown, as well as significant influence of sulphur on lamellar cracking susceptibility of steels. Possibility of prediction of lamellar cracking probability by the indices of reduction in area, impact toughness and critical crack opening displacement, as well as by delayed fracture critical stresses and fractographs of base metal fracture surface, is shown. 18 Ref., 2 Tables, 12 Figures.
 
 
Keywords: repair welded structures, main pipelines, cold cracks, lamellar cracking, thermal annealing effect, technological samples
 
 
Received:                05.06.14
Published:               28.11.14
 
 
References
1. But, V.S., Gretsky, Yu.Ya., Rozgonyuk, V.V. (2001) Substantiation of new approach to realize welding operations on pipelines under pressure. Naft. i Gaz. Promyslovist, 4, 33-39.
2. Drogomiretsky, M.M. (2006) In-pipe diagnostics of main gas pipelines and repair of detected defects. In: Proc. of Sci. Seminar on Reliability Assurance of Pipeline Transport Systems (Kiev, 11 April 2006). Kiev: Ekotekhnologiya.
3. But, V.S., Olejnik, O.I. (2007) Main trends in technology for repair of active pressurized main pipelines. The Paton Welding J., 5, 30-35.
4. GBN V.3.1-00013741-12:2011: Main gas pipelines. Repair arc welding in service conditions. Introd. 06.09.2011. Kiev: Ministry of Energy and Coal Industry of Ukraine.
5. But, V.S., Olejnik, O.I. (2011) Evaluation of technological and structural strength of welded joints of structures to be repaired on main pipelines. In: Proc. of Sci.-Pract. Conf. on Residual Resource and Problems of Modernization of Systems of Main and Commercial Pipelines (Kiev, 12-13 April 2011). Kiev: PWI.
6. Shorshorov, M.Kh., Chernyshova, T.A., Krasovsky, A.I. (1972) Weldability testing of metals. Moscow: Metallurgiya.
7. TU U 27.2-19305558-001:2007: Structural reinforcing elements of pipelines. Valid from 03.07.2007.
8. (1998) Kobelko Welding Today, 2, 2.
9. Makarov, E.L. (1981) Cold cracks in welding of alloy steels. Moscow: Mashinostroenie.
10. (1974) Technology of electric fusion welding of metals and alloys. Ed. by B.E. Paton. Moscow: Mashinostroenie.
11. Granjon, H.J. Recommendation for the use of Implant test as a complementary information test on the cold cracking susceptibility during the welding of steels. IIW Doc. IX 830-73.
12. GOST 23338-91: Welding of metals. Methods for determination of diffusion hydrogen content in deposited and weld metal. Introd. 01.07.92. Moscow: Gosstandart SSSR.
13. Suzuki, H. (1983) Weldability of modern structural steels in Japan. Transact. Iron and Steel Inst. of Japan, 23(3), 189-204. https://doi.org/10.2355/isijinternational1966.23.189
14. Vikhlevshchuk, V.A., Chernogritsky, V.M., Fedorova, I.P. (1989) Improvement of reliability of welded structures by reduction of sulfur content in steel. Avtomatich. Svarka, 4, 1-6.
15. Kirian, V.I. (1984) Method of evaluation of structural steel resistance to ductile fracture. Ibid., 11, 1-6.
16. Farrar, J.C.M., Dolby, R.E., Baker, R.G. (1969) Lamellar tearing in welded structural steels. Welding J., 7, 274-282.
17. But, V.S., Marchuk, Ya.S., Mandra, A.S. Method of joining of branchpipe to gas pipeline in service. Pat. 40033 Ukraine. Int. Cl. F16L 41/00. Publ. 25.03.2009.
18. But, V.S., Maksimov, S.Yu., Olejnik, O.I. et al. Process of liquidation of technological opennings in main pipelines. Pat. 11796 Ukraine. Int. Cl. F16L 55/16, E21F5/00. Publ. 16.01.2006.

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Suggested Citation

V.S. But, S.Yu. Maksimov And O.I. Olejnik (2014) Cracking susceptibility of welded joints in repair structures on main gas pipelines. The Paton Welding J., 11, 15-23.

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