Abstract
Hot-bended pipes are essential parts in the construction of long distance pipeline. They are usually made from longitudinally submerged arc welding (LSAW) pipes subjected to hot bending process including quenching and tempering process, which often deteriorates the impact property of the welded pipe. A hot-bended LSAW pipe with a wall thickness of 30.8 mm was fabricated by double-sided four wires submerged arc welding with solid wire and fused flux. Microstructural and property of both as-weld and as-bended pipe were examined. The pipes in two states show a similar tensile strength of 665–670 MPa, and fail in the heat affected zone during the tensile test. The weld metal of as-welded pipe consists of acicular ferrite and small fraction bainite and M-A constituents, while mixture of polygonal ferrite, degenerate perlite and precipitated carbides of metal elements was found in the weld metal of the as-bended pipe. The hot bending process decreases the fraction of acicular ferrite from 66.4 to 47.5%, and the fraction of high angle grain boundary from 76.8 to 67.1%. Therefore, both the type of microstructure and the fraction of ductile microstructures were the influencing factors of weld metal impact toughness, which lead to a reduction from 162 J to 84 J at −40°C.
Access provided by Autonomous University of Puebla. Download to read the full chapter text
Chapter PDF
Similar content being viewed by others
References
Hillenbrand H G, Kalwa C, Schröder J, et al. Challenges to a pipe manufacturer driven by worldwide pipe projects [C]. The Proceedings of The 18th Joint Technical Meeting on Pipeline Research, 2011, 13: 1–12.
Li Yanhua, Yang Junwei, Wang Wei. The application of hot-bending in large diameter pipeline [J]. Oil & Gas Storage and Transportation, 2002, 21(7): 49–51.
Meng J, Wang X, Wang M. Analyze the montanic pipeline construction bend and elbow measurement [C]. The Proceedings of The Second International Conference on IEEE, 2011: 2915–2917.
Song Ailing, Liang Guangchun, Wang Wenyao. Status quo and development of worldwide oiland gas pipelines [J]. Oil & Gas Storage and Transportation, 2006, 25(10): 1–6.
Zhang Xiaoli, Feng Qiang, Liu Yinglai, et al. Effect of reheating on toughness index and microstructure of high grade pipeline steels [J]. Transactions of Materials and Heat Treatment, 2008, 29(6): 66–69.
Zhang Xiaoli, Liu Yinglai, Feng Yaorong, et al. Relationship of microstructure and toughness index of reheated high grade pipeline steel [J]. Development and Application of Materials, 2008, 23(1): 1–4.
Arai Y, Kondo K, Hirata H, et al. Metallurgical design of newly developed material for seamless pipes of X80–X100 grades [J]. American Society of Mechanical Engineers, 2007, 4: 37–44.
Niu jing, Qi Lihua, Liu Yinglai, et al. Tempering microstructure and mechanical properties of pipeline steel X80 [J]. Transactions of Nonferrous Metals Society of China, 2009, 19: 573–578.
Guo Huiying, He Yuchun, Bao Binghui, et al. Effect of flux basicity on microstructure and low temperature toughness of SAW weld metal on X70 pipeline steel [J]. Hot Working Technology, 2013, 42(21): 39–42.
Junhua K, Lin Z, Bin G, et al. Influence of Mo content on microstructure and mechanical properties of high strength pipeline steel [J]. Materials & Design, 2004, 25(8): 723–728.
Yang Weiwei, Zhao Jing, Jiao Bin, et al. Analysis and comparison of the K65 steel grade standards [J]. Welded Pipe and Tube, 2013, 36(7): 67–71.
Chen Y T, Chen X, Ding Q F, et al. Microstructure and inclusion characterization in the simulated coarse-grain heat affected zone with large heat input of a Ti-Zr-Microalloyed HSLA steel [J]. ACTA Metallurgica Sinica, 2005, 18(2): 96–106.
Andrzej K L. Mechanical properties and microstructure of ULCB steels affected by thermo-mechanical rolling, quenching and tempering [J]. Journal of Materials Processing Technology, 2000, 106: 212–218.
Hwang B, Kim Y G, Lee S, et al. Effective grain size and charpy impact properties of high-toughness X70 pipeline steels [J]. Metallurgical and Materials Transactions A, 2005, 36(8): 2107–2114.
Pan Xin, Wang Yinbai, Zhang Yu. Development of the third generation of submerged arc welding wire for pipeline X90 [C]. The proceedings of the 23th National Technical Meeting of Metallic Products, 2013, Wuxi.
Gourgues A F, Flower H M, Lindley T C. Electron backscattering diffraction study of acicular ferrite, bainite, and martensite steel microstructures [J]. Materials Science and Technology, 2000, 16(1): 26–40.
Bhadeshia, H.K.D.H. Bainite in steels [M]. 2nd edition, London, The Inst. of Materials, Cambridge, 1992: 451.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2014 TMS
About this paper
Cite this paper
Dong, L., Zhang, Y., Pan, X., Wang, Y. (2014). Effect of Hot-Bending Process on Microstructure and Mechanical Property of K65 Submerged ARC Welded Pipe. In: Energy Materials 2014. Springer, Cham. https://doi.org/10.1007/978-3-319-48765-6_88
Download citation
DOI: https://doi.org/10.1007/978-3-319-48765-6_88
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-48598-0
Online ISBN: 978-3-319-48765-6
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)