Microstructure and Mechanical Properties of X80 Girth Welds with Different Welding Processes

Abstract:

X80 pipeline steels were employed to investigate the effects of two different welding processes (swing welding and row welding) on the quality of weld joints. The welding thermal cycles of multi-pass welding were tested and the microstructures of the two kinds of weld joints were studied by optical microscope. The hardness tests as well as low-temperature impact tests combined with fracture analysis with scanning electron microscope (SEM) were carried out to evaluate the properties of weld joints. The results showed that under the similar condition of heat input, the grain of swing welding joint is bigger than that of row welding. The joint of row welding has lower hardness and better toughness, suggesting that the process of row welding can improve the properties of weld metal. Consequently, though swing welding is simple in operation and good in production efficiency, row welding is better in terms of microstructure and properties of weld joints.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 1079-1087
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.1079
• Online since: June 2017
• Authors: Qian Wu*, Han Tao, Wang Yong, Hong Jie Zhang
• Keywords: Girth Weld, Mechanical Properties, Microstructure, Welding Process, X80 Pipeline Steel

References

[1] Li Helin. Developing Pulse and Prospect of Oil and Gas Transmission [J]. WELDED PIPE AND TUBE. 27-6 (2004) 1-11.

[2] A.R.H. Midawi, E.B.F. Santos, et al. Microstructures and mechanical properties in two X80 weld metals produced using similar heat input [J]. Journal of Materials Processing Technology, 226 (2015) 272-279.

DOI: 10.1016/j.jmatprotec.2015.07.019

[3] Shang C J, Wand X X, Liu Q Y, et al. Weldability of High Niobium X80 Pipeline Steel [C]. Proceedings of the International Seminar on Welding of High Strength Pipeline Steel. TMS, Araxa, Brazil. (2011) 435-453.

[4] J.A. Gianetto, J.T. Bowker, et al. Assessment of properties and microstructure of X100 pipeline girth welds [J]. Welding in the World. 49 (2015) 77-89.

DOI: 10.1007/bf03266505

[5] LI Xueda, FAN Yuran, CHEN Liang, SHANG Chengjia. Research on Relation between the Change Rule of Multiple Passes Circumferential Weld Microstructure and Impact Tough [J]. WELDED PIPE AND TUBE. 38-1 (2015) 11-16.

[6] Lambert-perlade A, Gourgues A F, Besson J, et al. Mechanisms and modeling of cleavage fracture in simulated heat-affected zone microstructures of a high-strength low alloy steel [J]. Metall Mater Trans A. 35A (2004) 1039-1053.

DOI: 10.1007/s11661-004-0030-y

[7] Nakao Y, Oshige H, Noi S, Nishi Y. Distribution of toughness in HAZ of multi-pass welded high strength steel [J]. Quarterly J. Japan Weld Soc. 3 (1985) 773-781.

DOI: 10.2207/qjjws.3.773

[8] Li Y, Baker T N. Effect of morphology of martensite-austenite phase on fracture of weld heat affected zone in vanadium and niobium microalloyed steels [J]. Mater Sci Technol. 26 (2010) 1029-1040.

DOI: 10.1179/026708309x12512744154360

[9] Mohseni P, SORBERG J K, KARLSEN M, et al. Cleavage Francture Initiation at M-A Constituents in Intercritically Coarse-Grained Heat-Affected Zone [J]. Metall Mater Trans. 45A (2014) 384-394.

DOI: 10.1007/s11661-013-2110-3

[10] Li Xueda. Study on the Weldability of the Third Generation Pipeline Steels [D]. Ph.D. thesis, University of Science and Technology Beijing, Beijing, China, (2015).

[11] ZHANG Mingyue, et al. Welding thermal simulation experiment on SMA490BW material [J]. Electric Welding Machine. 44-3 (2014) 65-69.