National University of Science and Technology MISiS, Moscow, Russia:

M. A. Tovmasyan, Lecturer, Metal Forming Dept., Vyksa affiliate, e-mail: i-margarit@yandex.ru
S. V. Samusev, Dr. Eng., Prof., Metal Forming Dept.

Studies have been carried out to assess the effect of residual stresses and deformations arising in the process of assembly and welding, as well as after metal cooling, on the shape of pipes. In the process of cooling, the weld and heat-affected sections are shortened, leading to a curvature of their generatrices, with the main change noted at the ends of pipes. To determine the stresses and strains in pipes, experimental and analytical studies and mathematical modeling were carried out at the assembly and welding site. Presented are the results of geometry measurements from the front and rear ends of pipe blanks and pipes with dimensions of 1420×25; 1420×21.6; 1420×18.7; 1420×15.7 mm of K60 strength class and 813×39; 813×37.4 and 813×39 mm of K65 strength class after step forming, assembly, welding and expansion, as well as the curvature of these pipes. The calculation of stress intensity along the entire perimeter of pipes 813×39 and 1420×25.8 mm before and after assembly on the assembly and welding mill was carried out. Pipes with a ratio of diameter to wall thickness of 90.4 of the K60 strength class had the largest deviation in ovality and curvature, and the smallest deviations were 20.8 and 22.3 of the K65 strength class. After welding of the external seams, the vertical diameter and the value of curvature increase, and after expansion they decrease. The total change in the ovality of pipes due to residual welding deformations is on average 0.5% for pipes with a diameter of 813 mm and 2% for pipes with a diameter of 1420 mm.

1. Tovmasyan M. A., Samusev S. V., Sazonov V. A. Study of the formation of large-diameter pipes with the use modern computer systems. Metallurgist. 2016. Vol. 60. No. 1–2. pp. 179–185.
2. Matveev М. Yu., Ivanov V. Ya., Grum-Grzhimaylo N. А. Production of large-diameter electricwelded pipes. Moscow: Metallurgiya, 1968. 192 p.
3. Samusev S. V., Zhigulev G. P., Skripalenko М. М., Fadeev V. А. Research of technological parameters of billet stepwise forming in production of large diameter tubes at tube electric pipe welded line TESA 1420. Chernye Metally. 2017. No. 9. pp. 73–77.
4. Vydrin А. V., Zalavin Ya. Е. Deformation and kinematic parameters of roller molding. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta. 2021. Vol. 21. No. 2. pp. 51–57.
5. Om H., Pandey S. Effect of heat input on dilution and heat affected zone in submerged arc welding process. Sadhana. 2013. Vol. 38. No. 6. pp. 1369– 1391.
6. Velichko А. А., Bortsov А. N., Shabalov I. P., Frontov I. I., Utkin I. Yu. The relationship of thermal processes with the morphology of welded joints and promising types of welding in relation to thick-walled electric-welded pipes. Metallurg. 2014. No. 3. pp. 72–77.
7. Muravyev V. I., Bakhmatov P. V., Pletnev N. О., Debelyak А. А. Effect of the stress state on the structure and properties during welding of structures made of steels and alloys. Izvestiya vuzov. Chernaya metallurgiya. 2016. Vol. 59. No. 4. pp. 251-255.
8. Оkerblom N. О. Welding deformations and stresses. Saint-Petersburg: Mashgiz, 1948. 271 p.
9. Li-Feng Fan, Jia-Xin Yan, Ying Gao, Jian-Bin Yun. Research on deformation characteristics of JCOE forming in large diameter welding pipe. Advanced Manufacturing Technology. 2016. No. 10. pp. 268–277.
10. Nóbrega J., Diniz D., Silva A. Numerical evaluation of temperature field and residual stresses in an API 5L X80 steel welded joint using the finite element method. Metals. 2016. Vol. 6, Iss. 28.
11. Nerovny V. М. Theory of welding processes: textbook for universities. 2^nd edition. Moscow: Izdatelstvo MGTU imeni N. E. Baumana, 2016. 702 p.
12. Soul F., Hamdy N. Numerical simulation of residual stress and strain behavior after temperature modification. USA: Welding Processes, 2012. 452 p.
13. Matveev М. Yu., Ruzhinskiy М. B., Romashov А. А. et al. Technology for production of electricwelded pipes. Moscow: Metallurgiya, 1967. 164 p.
14. GOST 26877–2008. Metal products. Methods of measuring form variations. Introduced: 01.01.2013. Moscow: Izdatelstvo standartov, 2013.
15. Samusev S. V., Skripalenko М. М., Fadeev V. А. Procedure for adjusting the roller beams of the assembly and welding mill of the TESA 1420 line for production of large-diameter welded pipes. Proizvodstvo prokata. 2017. No. 4. pp. 26–30.
16. Tovmasyan М. А., Samusev S. V. Analysis of the effect of uneven distribution of the mechanical properties of rolled sheets on the shape of a pipe billet after molding in the production of large-diameter pipes. Metally. 2020. No. 3. pp. 95–103.
17. Tovmasyan М. А., Samusev S. V. Experimental study of changes in the ovality of large diameter pipes, taking into account the influence of welding deformations. Chernye Metally. 2019. No. 9. pp. 43–49.
18. GOST 10704–91. Electrically welded steel line-weld tubes. Range. Introduced: 01.01.1999. Moscow: Izdatelstvo standartov, 1991.
19. GOST 20295–85. Steel welded pipes for main gas-and-oil pipelines. Specifications. Introduced: 01.01.1987. Moscow: Izdatelstvo standartov, 1985.