Statistical Assessment of Fracture Toughness Results from the HAZ of X80 Pipeline FCAW Girth Weld |
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| Authors: | Hongyuan Chen Qingshan Feng Ying Bi Xiongxiong Gao Lianshuang Dai Qiang Chi |
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| Affiliation: | 1.School of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China;2.State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, CNPC Tubular Goods Research Institute, Xi’an 710077, China;3.China Oil & Gas Piping Network Corporation, Beijing 100013, China;4.Xi’an Shiyou University, Xi’an 710069, China |
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| Abstract: | Due to the wide application of flux-cored arc welds (FCAW) susceptible to significant scatter in weld and Heat Affected Zone (HAZ) fracture toughness, there is an interest in methods for evaluating the reliability of welds containing defects. The mechanical properties of the FCAW girth weld of an X80 pipeline are tested and then analyzed. By obtaining fracture toughness results from a statistically significant number of SENB specimens, with notches positioned in different HAZ locations, the effect of variation within the results can be evaluated. The results of the fracture toughness tests were analyzed using statistical methods, to compare both the difference in behavior between HAZ microstructures and the variation when a similar microstructure has been sampled. The range of different characteristic toughness values was analyzed using a postulated ECA case to illustrate the sensitivity of the results to how toughness is defined. The analyses supported recommendations to be made on the optimum approach to characterizing HAZ fracture toughness for reliable pipeline assessments in multi-pass girth welds with complex HAZ microstructure distributions. |
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| Keywords: | statistical assessment X80 pipeline girth weld fracture toughness |
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