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Failure Analysis of Cracked P110 Repaired Tubing Used for Gas Transmission

With green and low-carbon developments in oil fields, an increasing amount of repaired oil tubing is being used as oil and gas transmission pipelines in China. However, due to differences in manufacturing standards between oil tubing and transmission pipelines, there are inevitably some issues durin...

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Autores principales: Zhang, Shuxin, Xie, Faqin, Wu, Xiangqing, Yan, Xi, Luo, Jinheng, Ma, Xiaoliang, Su, Gege
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10672527/
https://www.ncbi.nlm.nih.gov/pubmed/38005091
http://dx.doi.org/10.3390/ma16227151
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author Zhang, Shuxin
Xie, Faqin
Wu, Xiangqing
Yan, Xi
Luo, Jinheng
Ma, Xiaoliang
Su, Gege
author_facet Zhang, Shuxin
Xie, Faqin
Wu, Xiangqing
Yan, Xi
Luo, Jinheng
Ma, Xiaoliang
Su, Gege
author_sort Zhang, Shuxin
collection PubMed
description With green and low-carbon developments in oil fields, an increasing amount of repaired oil tubing is being used as oil and gas transmission pipelines in China. However, due to differences in manufacturing standards between oil tubing and transmission pipelines, there are inevitably some issues during their use. This paper investigates a case of cracking failure in repaired oil tubing used as a gathering and transportation pipeline. The failure occurred after eight months of operation and was characterized by a circumferential crack at the male thread end of the tubing joint. To determine the root cause of the failure, a series of experiments were conducted on the oil tubing. The experiments included visual inspection, chemical composition analysis, mechanical properties testing, hardness testing, metallographic examination, and microstructure analysis. The results revealed that the thread of the cracked tubing was not tightened to the specified position; the connection between the tubing and the coupling was welded in a circumferential direction; and cracks occurred in the heat-affected zone of the weld. Chemical composition, tensile performance, and the Charpy impact of the tubing meet the requirements of API 5CT for P110 material, and no abnormalities were found in the metallographic structure. The microstructure at the weld toe of the fracture is martensite, and the hardness is 476 HV10. Based on the thermal simulation verification test, when the material of the tubing cools from 1200 °C, which is located in the coarse HAZ temperature zone, the base metal transforms into martensite with a little granular bainite, exhibiting its highest hardness value at 371 HV10, which is higher than the allowable hardness for carbon steel and indicates the material has poor weldability. The reasons for the cracking and failure of the tubing are that the P110 repaired tubing has a high carbon equivalent and poor weldability. During the welding process, martensitic structure was formed at the weld toe, and cold cracks appeared in the heat-affected zone, resulting in failure. To avoid the reoccurrence of such failure, recommendations are proposed.
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spelling pubmed-106725272023-11-14 Failure Analysis of Cracked P110 Repaired Tubing Used for Gas Transmission Zhang, Shuxin Xie, Faqin Wu, Xiangqing Yan, Xi Luo, Jinheng Ma, Xiaoliang Su, Gege Materials (Basel) Article With green and low-carbon developments in oil fields, an increasing amount of repaired oil tubing is being used as oil and gas transmission pipelines in China. However, due to differences in manufacturing standards between oil tubing and transmission pipelines, there are inevitably some issues during their use. This paper investigates a case of cracking failure in repaired oil tubing used as a gathering and transportation pipeline. The failure occurred after eight months of operation and was characterized by a circumferential crack at the male thread end of the tubing joint. To determine the root cause of the failure, a series of experiments were conducted on the oil tubing. The experiments included visual inspection, chemical composition analysis, mechanical properties testing, hardness testing, metallographic examination, and microstructure analysis. The results revealed that the thread of the cracked tubing was not tightened to the specified position; the connection between the tubing and the coupling was welded in a circumferential direction; and cracks occurred in the heat-affected zone of the weld. Chemical composition, tensile performance, and the Charpy impact of the tubing meet the requirements of API 5CT for P110 material, and no abnormalities were found in the metallographic structure. The microstructure at the weld toe of the fracture is martensite, and the hardness is 476 HV10. Based on the thermal simulation verification test, when the material of the tubing cools from 1200 °C, which is located in the coarse HAZ temperature zone, the base metal transforms into martensite with a little granular bainite, exhibiting its highest hardness value at 371 HV10, which is higher than the allowable hardness for carbon steel and indicates the material has poor weldability. The reasons for the cracking and failure of the tubing are that the P110 repaired tubing has a high carbon equivalent and poor weldability. During the welding process, martensitic structure was formed at the weld toe, and cold cracks appeared in the heat-affected zone, resulting in failure. To avoid the reoccurrence of such failure, recommendations are proposed. MDPI 2023-11-14 /pmc/articles/PMC10672527/ /pubmed/38005091 http://dx.doi.org/10.3390/ma16227151 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Zhang, Shuxin
Xie, Faqin
Wu, Xiangqing
Yan, Xi
Luo, Jinheng
Ma, Xiaoliang
Su, Gege
Failure Analysis of Cracked P110 Repaired Tubing Used for Gas Transmission
title Failure Analysis of Cracked P110 Repaired Tubing Used for Gas Transmission
title_full Failure Analysis of Cracked P110 Repaired Tubing Used for Gas Transmission
title_fullStr Failure Analysis of Cracked P110 Repaired Tubing Used for Gas Transmission
title_full_unstemmed Failure Analysis of Cracked P110 Repaired Tubing Used for Gas Transmission
title_short Failure Analysis of Cracked P110 Repaired Tubing Used for Gas Transmission
title_sort failure analysis of cracked p110 repaired tubing used for gas transmission
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10672527/
https://www.ncbi.nlm.nih.gov/pubmed/38005091
http://dx.doi.org/10.3390/ma16227151
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