The primary objectives of this program were to provide a better understanding of the factors that control strength and toughness in high strength steel girth welds and to develop optimized welding consumables and welding procedures for high strength pipelines. The initial work on the program involved developing cooling rate models so that optimized weld metal compositions for high-strength pipelines could be developed, ensuring that the ideal balance of strength and ductility, together with tolerance to process variations and resistance to hydrogen cracking is achieved. The model, which was developed under a companion program, uses a two-dimensional finite element approach. Complete details can be found in Reference . The model predicts the cooling rates during various weld passes in narrow groove welding of X80 and X100 pipes. Using this model, along with experimental datasets, a neural network model was developed which has been used to predict weld metal properties for various weld metal compositions. Based on the predictions, eight target compositions were selected and were manufactured by one of the team partners. The results of mechanical property testing showed that it was possible to develop weld metal compositions which exceeded the target yield strength of 820 MPa and also provided excellent toughness (>50J at −60°C). It was also found that the weld metal yield strength measured close to the ID of the pipe was significantly higher than that which was measured closer to the OD of the pipe. Complete mechanical property results, including results for round-bar and strip tensiles, CVN impact toughness, microhardness and more, are presented.
- International Petroleum Technology Institute and the Pipeline Division
Development of Optimized Weld Metal Chemistries for Pipeline Girth Welding of High Strength Line Pipe
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Fiore, SR, Gianetto, JA, Hudson, MG, Vaze, S, Khurana, S, Bowker, JT, & Dorling, DV. "Development of Optimized Weld Metal Chemistries for Pipeline Girth Welding of High Strength Line Pipe." Proceedings of the 2008 7th International Pipeline Conference. 2008 7th International Pipeline Conference, Volume 3. Calgary, Alberta, Canada. September 29–October 3, 2008. pp. 417-428. ASME. https://doi.org/10.1115/IPC2008-64593
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