Low-Cycle Fatigue Properties of the X70 High-Frequency Electric-Resistant Welded Pipes

The strength, toughness, corrosion, and fatigue resistance are the main requirements for evaluating the integrity of a pipeline. In this study, the tensile strength, impact toughness, and fatigue properties of the pipe body and weld joint of an X70 high-frequency electric-resistant welded (HFW) pipe...

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Main Authors: Peng Tian, Kai Xu, Guang-ping Lu, Gui-ying Qiao, Fu-ren Xiao
Format: Article
Language:English
Published: Wiley 2018-01-01
Series:Advances in Materials Science and Engineering
Online Access:http://dx.doi.org/10.1155/2018/2358038
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author Peng Tian
Kai Xu
Guang-ping Lu
Gui-ying Qiao
Fu-ren Xiao
author_facet Peng Tian
Kai Xu
Guang-ping Lu
Gui-ying Qiao
Fu-ren Xiao
author_sort Peng Tian
collection DOAJ
description The strength, toughness, corrosion, and fatigue resistance are the main requirements for evaluating the integrity of a pipeline. In this study, the tensile strength, impact toughness, and fatigue properties of the pipe body and weld joint of an X70 high-frequency electric-resistant welded (HFW) pipe were measured and the effects of microstructure and surface defects at weld joint on properties were discussed. Results show the appearance of a weakened zone at the weld joint of the X70 HFW pipe. Nevertheless, all mechanical properties, including strength and impact energy, were superior to the specified values of the API specifications for the X70 line pipe. The reduced strength, toughness, and resistance to S-N fatigue of the weld joint caused the microstructural coarsening at the weld junction zone. However, for the specimens without surface finishing, the resistance to S-N fatigue for the weld joint was further reduced. This phenomenon was mainly attributed to the burring defects and microstructural coarsening at the heat-affected zone (HAZ). Therefore, to improve the quality of the X70 HFW pipe, refining the microstructure of weld joint and reducing the deburring defects by optimizing the postweld heat treatment (PWHT) and deburring processes should be firstly considered in the future research works.
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publishDate 2018-01-01
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series Advances in Materials Science and Engineering
spelling doaj-art-bfaa4e57520a4c63bdc5f1d0fcc3579e2025-08-20T03:22:39ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422018-01-01201810.1155/2018/23580382358038Low-Cycle Fatigue Properties of the X70 High-Frequency Electric-Resistant Welded PipesPeng Tian0Kai Xu1Guang-ping Lu2Gui-ying Qiao3Fu-ren Xiao4Key Lab of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, ChinaKey Lab of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, ChinaYangzhou Subsidiary, North China Petroleum Steel Pipe Co., Ltd., CNPC Bohai Equipment Manufacturing Co., Ltd., Yangzhou 225128, ChinaKey Lab of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, ChinaKey Lab of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, ChinaThe strength, toughness, corrosion, and fatigue resistance are the main requirements for evaluating the integrity of a pipeline. In this study, the tensile strength, impact toughness, and fatigue properties of the pipe body and weld joint of an X70 high-frequency electric-resistant welded (HFW) pipe were measured and the effects of microstructure and surface defects at weld joint on properties were discussed. Results show the appearance of a weakened zone at the weld joint of the X70 HFW pipe. Nevertheless, all mechanical properties, including strength and impact energy, were superior to the specified values of the API specifications for the X70 line pipe. The reduced strength, toughness, and resistance to S-N fatigue of the weld joint caused the microstructural coarsening at the weld junction zone. However, for the specimens without surface finishing, the resistance to S-N fatigue for the weld joint was further reduced. This phenomenon was mainly attributed to the burring defects and microstructural coarsening at the heat-affected zone (HAZ). Therefore, to improve the quality of the X70 HFW pipe, refining the microstructure of weld joint and reducing the deburring defects by optimizing the postweld heat treatment (PWHT) and deburring processes should be firstly considered in the future research works.http://dx.doi.org/10.1155/2018/2358038
spellingShingle Peng Tian
Kai Xu
Guang-ping Lu
Gui-ying Qiao
Fu-ren Xiao
Low-Cycle Fatigue Properties of the X70 High-Frequency Electric-Resistant Welded Pipes
Advances in Materials Science and Engineering
title Low-Cycle Fatigue Properties of the X70 High-Frequency Electric-Resistant Welded Pipes
title_full Low-Cycle Fatigue Properties of the X70 High-Frequency Electric-Resistant Welded Pipes
title_fullStr Low-Cycle Fatigue Properties of the X70 High-Frequency Electric-Resistant Welded Pipes
title_full_unstemmed Low-Cycle Fatigue Properties of the X70 High-Frequency Electric-Resistant Welded Pipes
title_short Low-Cycle Fatigue Properties of the X70 High-Frequency Electric-Resistant Welded Pipes
title_sort low cycle fatigue properties of the x70 high frequency electric resistant welded pipes
url http://dx.doi.org/10.1155/2018/2358038
work_keys_str_mv AT pengtian lowcyclefatiguepropertiesofthex70highfrequencyelectricresistantweldedpipes
AT kaixu lowcyclefatiguepropertiesofthex70highfrequencyelectricresistantweldedpipes
AT guangpinglu lowcyclefatiguepropertiesofthex70highfrequencyelectricresistantweldedpipes
AT guiyingqiao lowcyclefatiguepropertiesofthex70highfrequencyelectricresistantweldedpipes
AT furenxiao lowcyclefatiguepropertiesofthex70highfrequencyelectricresistantweldedpipes