Pub Date : 2026-06-01Epub Date: 2026-01-20DOI: 10.1016/j.ijpvp.2026.105761
Tongtong Yu , Shitong Wei , Shanping Lu
To improve the high-temperature stability of high-Si 9Cr steel weld metals for lead-cooled fast reactors, this work examines how nickel (Ni) affects the microstructure and properties of 9Cr-1.07Si deposited metals during long-term aging and creep rupture. Tests were conducted at 550 °C on two Ni levels samples (0.61 wt% and 1.46 wt%) to compare their thermal aging and creep rupture behaviors. The results indicate that Ni promotes the formation of M6X. This phase acts as an intermediate between M23C6 and Laves phases, facilitating the development of large-sized precipitate clusters and consequently degrading the mechanical properties during aging. Furthermore, post-weld heat treatment (PWHT) enhances microstructural stability during thermal exposure by forming fine M23C6 pinning the grain boundaries. After aging for 10,000 h, the average size of precipitates of specimen without PWHT is 14 % larger than that of specimen with PWHT. Creep rupture tests were thus performed on the PWHT specimens to assess their creep rupture performance. As the precipitates coarsen, their grain-boundary pinning effect weakens, reducing creep resistance, inducing cavities and ultimately leading to fracture through combining cavity growth and deformation. Furthermore, the promotion of M6X coarsening by the increasing Ni content results in lower creep resistance in high-Ni specimen. Under 225 MPa, the average rupture life of 146Ni (89 h) is significantly lower than that of 61Ni (4282 h).
{"title":"Microstructure evolution and creep property of Ni-bearing 9Cr heat-resistant steel deposited metals","authors":"Tongtong Yu , Shitong Wei , Shanping Lu","doi":"10.1016/j.ijpvp.2026.105761","DOIUrl":"10.1016/j.ijpvp.2026.105761","url":null,"abstract":"<div><div>To improve the high-temperature stability of high-Si 9Cr steel weld metals for lead-cooled fast reactors, this work examines how nickel (Ni) affects the microstructure and properties of 9Cr-1.07Si deposited metals during long-term aging and creep rupture. Tests were conducted at 550 °C on two Ni levels samples (0.61 wt% and 1.46 wt%) to compare their thermal aging and creep rupture behaviors. The results indicate that Ni promotes the formation of M<sub>6</sub>X. This phase acts as an intermediate between M<sub>23</sub>C<sub>6</sub> and Laves phases, facilitating the development of large-sized precipitate clusters and consequently degrading the mechanical properties during aging. Furthermore, post-weld heat treatment (PWHT) enhances microstructural stability during thermal exposure by forming fine M<sub>23</sub>C<sub>6</sub> pinning the grain boundaries. After aging for 10,000 h, the average size of precipitates of specimen without PWHT is 14 % larger than that of specimen with PWHT. <strong>C</strong>reep rupture tests <strong>were thus</strong> performed on the PWHT specimens to assess their creep rupture performance. As the precipitates coarsen, their grain-boundary pinning effect weakens, reducing creep resistance, inducing cavities and ultimately leading to fracture through combining cavity growth and deformation. Furthermore, the promotion of M<sub>6</sub>X coarsening by the increasing Ni content results in lower creep resistance in high-Ni specimen. Under 225 MPa, the average rupture life of 146Ni (89 h) is significantly lower than that of 61Ni (4282 h).</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105761"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the evolution of localized pitting and intergranular corrosion (IGC) of 2195-T8 Al-Cu-Li alloy in an acidic environment was investigated by integrating microstructural characterization with 3D cellular automata (CA) simulation. Microstructural features, including the rolled grain morphology and the heterogeneous distribution of intermetallic compounds (IMs), were characterized using EBSD and TEM. An improved Voronoi-based approach was employed to reconstruct a rolled polycrystalline microstructure by incorporating EBSD-derived grain statistics. Immersion tests in 30 % HNO3 combined with quasi-in-situ SEM-FIB were conducted to reveal corrosion morphologies associated with IMs dissolution and preferential grain-boundary attack. Based on the corrosion mechanism of Al-Cu-Li alloys in acidic media, a microstructure-informed 3D CA model was developed by explicitly embedding the spatial distribution of IMs using six cell types and five transition rules. The model reproduces key processes including selective/partial IM dissolution, preferential grain-boundary dissolution, galvanic-driven matrix dissolution, and pit growth, and the simulated morphological evolution shows good qualitative and semi-quantitative agreement with experiments.
{"title":"Research on the evolution law of corrosion damage of 2195 Al-Cu-Li alloy in acidic environments and cellular automata simulation","authors":"Xinzhi Yang, Gan Tian, Dejun Liu, Hongsheng Liu, Hui Cai, Mengqing Liu, Biyun Ren","doi":"10.1016/j.ijpvp.2026.105755","DOIUrl":"10.1016/j.ijpvp.2026.105755","url":null,"abstract":"<div><div>In this study, the evolution of localized pitting and intergranular corrosion (IGC) of 2195-T8 Al-Cu-Li alloy in an acidic environment was investigated by integrating microstructural characterization with 3D cellular automata (CA) simulation. Microstructural features, including the rolled grain morphology and the heterogeneous distribution of intermetallic compounds (IMs), were characterized using EBSD and TEM. An improved Voronoi-based approach was employed to reconstruct a rolled polycrystalline microstructure by incorporating EBSD-derived grain statistics. Immersion tests in 30 % HNO<sub>3</sub> combined with quasi-in-situ SEM-FIB were conducted to reveal corrosion morphologies associated with IMs dissolution and preferential grain-boundary attack. Based on the corrosion mechanism of Al-Cu-Li alloys in acidic media, a microstructure-informed 3D CA model was developed by explicitly embedding the spatial distribution of IMs using six cell types and five transition rules. The model reproduces key processes including selective/partial IM dissolution, preferential grain-boundary dissolution, galvanic-driven matrix dissolution, and pit growth, and the simulated morphological evolution shows good qualitative and semi-quantitative agreement with experiments.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105755"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-13DOI: 10.1016/j.ijpvp.2026.105759
Qingmei Jiang , Xiaoqiang Zhang , Yuguang Cao , Yaya He , Ying Zhen , Guiyi Wu
The global oil and gas pipeline industry has experienced rapid development, with a significant number of pipelines located in geologically challenging areas prone to earthquakes, permafrost, landslides, and other conditions that induce large deformations. For the safety design and assessment of large-deformation pipelines, strain-based criteria offer a more rational approach, especially for girth welds, which are the primary weak points in pipeline integrity. The tensile strain capacity model for pipeline girth welds serves as an effective strain-based criterion. However, existing research provides limited modeling approaches specifically for wide-groove girth welds produced by flux cored arc welding (FCAW) and shielded metal arc welding (SMAW). Existing models inadequately account for key factors influencing strain capacity, such as heat affected zone (HAZ) softening rates, low-strength matching coefficients, internal pressure, and high-low misalignment. Furthermore, these models are based on static crack methodologies, failing to fully capture the ductile tearing characteristics of girth welds, thereby underestimating their strain capacity. To address these gaps, this study employs a dynamic fracture numerical analysis method for pipeline girth welds to comprehensively investigate the factors affecting the strain capacity of combined automatic welding. Based on research patterns and numerical experimental data, an accurate and effective tensile strain capacity model for FCAW/SMAW girth welds is developed. The reliability of the proposed model is validated through comparisons with published experimental results, establishing a strain-based evaluation framework for engineering applications involving FCAW/SMAW girth welds.
{"title":"Research on tensile strain capacity model for FCAW/SMAW girth weld pipeline","authors":"Qingmei Jiang , Xiaoqiang Zhang , Yuguang Cao , Yaya He , Ying Zhen , Guiyi Wu","doi":"10.1016/j.ijpvp.2026.105759","DOIUrl":"10.1016/j.ijpvp.2026.105759","url":null,"abstract":"<div><div>The global oil and gas pipeline industry has experienced rapid development, with a significant number of pipelines located in geologically challenging areas prone to earthquakes, permafrost, landslides, and other conditions that induce large deformations. For the safety design and assessment of large-deformation pipelines, strain-based criteria offer a more rational approach, especially for girth welds, which are the primary weak points in pipeline integrity. The tensile strain capacity model for pipeline girth welds serves as an effective strain-based criterion. However, existing research provides limited modeling approaches specifically for wide-groove girth welds produced by flux cored arc welding (FCAW) and shielded metal arc welding (SMAW). Existing models inadequately account for key factors influencing strain capacity, such as heat affected zone (HAZ) softening rates, low-strength matching coefficients, internal pressure, and high-low misalignment. Furthermore, these models are based on static crack methodologies, failing to fully capture the ductile tearing characteristics of girth welds, thereby underestimating their strain capacity. To address these gaps, this study employs a dynamic fracture numerical analysis method for pipeline girth welds to comprehensively investigate the factors affecting the strain capacity of combined automatic welding. Based on research patterns and numerical experimental data, an accurate and effective tensile strain capacity model for FCAW/SMAW girth welds is developed. The reliability of the proposed model is validated through comparisons with published experimental results, establishing a strain-based evaluation framework for engineering applications involving FCAW/SMAW girth welds.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105759"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-08DOI: 10.1016/j.ijpvp.2025.105743
A. Oñate , J. Ramirez , G. Dueña , M. Melendrez , C. Lanziotti , R. Apablaza , D. Rojas
This study investigated the premature failure of a welded 2205 duplex stainless steel tube operating in a black liquor heat exchanger at a pulp and paper plant. Although the component was designed for a ten-year service life, failure occurred after only two years, with macroscopic evidence of pitting corrosion aligned along the longitudinal weld. Metallographic examination revealed localized attack progressing intergranularly between ferrite and austenite. SEM-EDS analysis identified pronounced Cr, Mo, and Ni segregation near the weld bead, while XRD combined with Rietveld refinement quantified approximately 3.6 wt% sigma phase in the weld/HAZ region. As a consequence of these welding-induced microstructural changes, electrochemical tests in 0.6 M NaCl showed metastable passivity and higher current densities in the weld zone. Under alkaline conditions at 65 °C, the welded joint exhibited a reduction in corrosion resistance compared with the base metal. The modeled TTT-CCT diagram for the alloy composition supported the experimental observations, indicating that the welding thermal cycle intersected the sigma-forming region. Overall, the results demonstrate that thermal exposure during welding promoted elemental segregation and sigma-phase nucleation, creating galvanic microcells that facilitated localized corrosion and intergranular propagation. These findings underscore the need for stricter thermal control and post-fabrication verification of welded 2205 duplex stainless steel components operating in high-temperature, high-pH environments.
本研究调查了在纸浆和造纸厂黑液热交换器中工作的2205双相不锈钢焊接管的过早失效。尽管该组件的设计使用寿命为10年，但仅在两年后就发生了故障，在纵向焊缝上出现了宏观的点蚀迹象。金相检查显示铁素体和奥氏体之间的局部攻击在晶间进展。SEM-EDS分析发现焊缝附近存在明显的Cr、Mo和Ni偏析，而XRD结合Rietveld精细化分析发现焊缝/HAZ区域约有3.6 wt%的sigma相。由于这些焊接引起的微观结构变化，在0.6 M NaCl中进行电化学测试，焊缝区显示出亚稳钝化和更高的电流密度。在65℃的碱性条件下，与母材相比，焊接接头的耐腐蚀性降低。模拟的合金成分TTT-CCT图与实验结果相吻合，表明焊接热循环与sigma形成区相交。总的来说，结果表明，焊接过程中的热暴露促进了元素偏析和sigma相成核，产生了有利于局部腐蚀和晶间扩展的原电微细胞。这些发现强调了在高温、高ph值环境下工作的焊接2205双相不锈钢部件需要更严格的热控制和制造后验证。
{"title":"Failure analysis of a 2205 duplex stainless steel tube affected by localized corrosion in a black liquor heat exchanger","authors":"A. Oñate , J. Ramirez , G. Dueña , M. Melendrez , C. Lanziotti , R. Apablaza , D. Rojas","doi":"10.1016/j.ijpvp.2025.105743","DOIUrl":"10.1016/j.ijpvp.2025.105743","url":null,"abstract":"<div><div>This study investigated the premature failure of a welded 2205 duplex stainless steel tube operating in a black liquor heat exchanger at a pulp and paper plant. Although the component was designed for a ten-year service life, failure occurred after only two years, with macroscopic evidence of pitting corrosion aligned along the longitudinal weld. Metallographic examination revealed localized attack progressing intergranularly between ferrite and austenite. SEM-EDS analysis identified pronounced Cr, Mo, and Ni segregation near the weld bead, while XRD combined with Rietveld refinement quantified approximately 3.6 wt% sigma phase in the weld/HAZ region. As a consequence of these welding-induced microstructural changes, electrochemical tests in 0.6 M NaCl showed metastable passivity and higher current densities in the weld zone. Under alkaline conditions at 65 °C, the welded joint exhibited a reduction in corrosion resistance compared with the base metal. The modeled TTT-CCT diagram for the alloy composition supported the experimental observations, indicating that the welding thermal cycle intersected the sigma-forming region. Overall, the results demonstrate that thermal exposure during welding promoted elemental segregation and sigma-phase nucleation, creating galvanic microcells that facilitated localized corrosion and intergranular propagation. These findings underscore the need for stricter thermal control and post-fabrication verification of welded 2205 duplex stainless steel components operating in high-temperature, high-pH environments.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105743"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-27DOI: 10.1016/j.ijpvp.2026.105763
Masayuki Kamaya
This study proposes a procedure applicable to fitness-for-service codes to predict ductile failure of a cracked pipe subjected to a bending load. The procedure requires only the yield (proof) and tensile strengths as material properties to predict the failure moment. First, a four-point bending test was conducted using eight stainless steel specimens. The specimens failed due to crack penetration or buckling of the pipe. Then, based on finite element analysis, the moment at ductile crack penetration was predicted using a stress–strain curve accounting for the work hardening properties of the material and a failure criterion for the specimen. The specimen was assumed to have failed when the equivalent stress at a monitoring point reached the flow stress. It was demonstrated that the proposed procedure reasonably predicted the critical moment for ductile crack penetration. On the other hand, the procedure was not suitable for predicting failure due to buckling of the pipe. By introducing a threshold stress, defined as twice the yield strength, to account for failure due to pipe buckling, the failure moment obtained by the tests could be predicted with reasonable accuracy.
{"title":"A procedure for predicting failure moment of stainless steel pipes with a circumferential crack under bending load","authors":"Masayuki Kamaya","doi":"10.1016/j.ijpvp.2026.105763","DOIUrl":"10.1016/j.ijpvp.2026.105763","url":null,"abstract":"<div><div>This study proposes a procedure applicable to fitness-for-service codes to predict ductile failure of a cracked pipe subjected to a bending load. The procedure requires only the yield (proof) and tensile strengths as material properties to predict the failure moment. First, a four-point bending test was conducted using eight stainless steel specimens. The specimens failed due to crack penetration or buckling of the pipe. Then, based on finite element analysis, the moment at ductile crack penetration was predicted using a stress–strain curve accounting for the work hardening properties of the material and a failure criterion for the specimen. The specimen was assumed to have failed when the equivalent stress at a monitoring point reached the flow stress. It was demonstrated that the proposed procedure reasonably predicted the critical moment for ductile crack penetration. On the other hand, the procedure was not suitable for predicting failure due to buckling of the pipe. By introducing a threshold stress, defined as twice the yield strength, to account for failure due to pipe buckling, the failure moment obtained by the tests could be predicted with reasonable accuracy.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105763"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-28DOI: 10.1016/j.ijpvp.2026.105765
Qiaoling Chu , Zhikun Wang , Dan Yang , Junyao Wang , Fanghua Liao , Zhe Chang , Kai Cao , Saifei Zhang
The microstructural evolution and mechanical property changes of CMT-fabricated Inconel 625 cladding layers under accelerated thermal aging (700 and 800 °C, up to 480 h) were systematically investigated. The as-deposited microstructure consisted of columnar grains with interdendritic chain-like Laves phases. Thermal aging promoted the precipitation of carbides and intermetallic phases, particularly δ-Ni3Nb, whose content increased significantly with rising temperature (700 → 800 °C) and prolonged exposure time at 800 °C. The γ-Ni grain size of Inconel 625 remained stable during aging, contrasting with notable grain coarsening in the 15CrMoG base metals. Mechanical properties exhibited temperature- and time-dependent degradation: hardness increased while bending ductility decreased with extended aging, attributable to δ-Ni3Nb embrittlement. To mitigate δ-Ni3Nb-induced brittleness, the operational temperature of Inconel 625 claddings on boiler tubes should be limited to below 700 °C.
{"title":"Microstructural evolutions and mechanical behavior of Inconel 625 CMT cladding layers during accelerated thermal aging","authors":"Qiaoling Chu , Zhikun Wang , Dan Yang , Junyao Wang , Fanghua Liao , Zhe Chang , Kai Cao , Saifei Zhang","doi":"10.1016/j.ijpvp.2026.105765","DOIUrl":"10.1016/j.ijpvp.2026.105765","url":null,"abstract":"<div><div>The microstructural evolution and mechanical property changes of CMT-fabricated Inconel 625 cladding layers under accelerated thermal aging (700 and 800 °C, up to 480 h) were systematically investigated. The as-deposited microstructure consisted of columnar grains with interdendritic chain-like Laves phases. Thermal aging promoted the precipitation of carbides and intermetallic phases, particularly δ-Ni<sub>3</sub>Nb, whose content increased significantly with rising temperature (700 → 800 °C) and prolonged exposure time at 800 °C. The γ-Ni grain size of Inconel 625 remained stable during aging, contrasting with notable grain coarsening in the 15CrMoG base metals. Mechanical properties exhibited temperature- and time-dependent degradation: hardness increased while bending ductility decreased with extended aging, attributable to δ-Ni<sub>3</sub>Nb embrittlement. To mitigate δ-Ni<sub>3</sub>Nb-induced brittleness, the operational temperature of Inconel 625 claddings on boiler tubes should be limited to below 700 °C.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105765"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-03DOI: 10.1016/j.ijpvp.2025.105741
Lei Chen , Wenjing Yang , Jianping Zhou , Zhenxi Liu , Zhanshu Lv , Yanwei Hu , Jian Li , Xingqing Yan , Jianliang Yu , Shaoyun Chen
To address the safety risks associated with pipeline fractures in carbon capture, utilization, and storage (CCUS) systems, this study constructed a full-scale experimental platform for supercritical CO2 pipelines containing impurities and conducted systematic fracture tests under three sets of conditions with varying initial pressures (9.8–11.6 MPa) and N2 molar concentrations (2 %–4 %). A self-developed data acquisition system, integrated with high-frequency pressure transducers, T-type armored thermocouples, and a high-speed camera (capturing crack propagation processes), was employed to monitor the dynamic evolutions of pressure, temperature, decompression wave propagation, and crack tip behavior during pipeline fracture. The results indicated that pipeline fracture induced four distinct pressure change stages: rapid decline (Stage Ⅰ), pressure oscillation (Stage Ⅱ), negative exponential decline (Stage Ⅲ), and static leakage (Stage Ⅳ). Axially, the internal temperature decreased first near the fracture and later at locations farther from it; vertically, the minimum temperature at all measuring points predominantly occurred at the pipeline bottom. The decompression wave velocity exhibited a linear decrease in Stage Ⅰ, formed a “pressure plateau” in Stage Ⅱ, and decreased irregularly in Stages Ⅲ–Ⅳ due to subcooled and superheated states caused by pressure instability. Higher initial pressure and N2 molar concentration both contributed to an increase in the initial decompression wave velocity and the “pressure plateau” value. Additionally, the self-designed fracture recording system successfully captured the complete process of pipeline failure, crack initiation, ductile propagation, and arrest. The crack tip opening angle (CTOA) fluctuated within 14.3°–21.2° along the propagation path and showed a gradual decreasing trend, while the crack propagation velocity first increased, maintained a stable phase, and then decreased. Notably, a higher N2 molar concentration led to a higher stable fracture velocity. This research provides critical experimental data and theoretical support for the safety design and fracture control of supercritical CO2 pipelines in CCUS projects.
{"title":"Experimental investigation on full-scale fracture behavior and dynamic response of supercritical CO2 pipelines with N2 impurities","authors":"Lei Chen , Wenjing Yang , Jianping Zhou , Zhenxi Liu , Zhanshu Lv , Yanwei Hu , Jian Li , Xingqing Yan , Jianliang Yu , Shaoyun Chen","doi":"10.1016/j.ijpvp.2025.105741","DOIUrl":"10.1016/j.ijpvp.2025.105741","url":null,"abstract":"<div><div>To address the safety risks associated with pipeline fractures in carbon capture, utilization, and storage (CCUS) systems, this study constructed a full-scale experimental platform for supercritical CO<sub>2</sub> pipelines containing impurities and conducted systematic fracture tests under three sets of conditions with varying initial pressures (9.8–11.6 MPa) and N<sub>2</sub> molar concentrations (2 %–4 %). A self-developed data acquisition system, integrated with high-frequency pressure transducers, T-type armored thermocouples, and a high-speed camera (capturing crack propagation processes), was employed to monitor the dynamic evolutions of pressure, temperature, decompression wave propagation, and crack tip behavior during pipeline fracture. The results indicated that pipeline fracture induced four distinct pressure change stages: rapid decline (Stage Ⅰ), pressure oscillation (Stage Ⅱ), negative exponential decline (Stage Ⅲ), and static leakage (Stage Ⅳ). Axially, the internal temperature decreased first near the fracture and later at locations farther from it; vertically, the minimum temperature at all measuring points predominantly occurred at the pipeline bottom. The decompression wave velocity exhibited a linear decrease in Stage Ⅰ, formed a “pressure plateau” in Stage Ⅱ, and decreased irregularly in Stages Ⅲ–Ⅳ due to subcooled and superheated states caused by pressure instability. Higher initial pressure and N<sub>2</sub> molar concentration both contributed to an increase in the initial decompression wave velocity and the “pressure plateau” value. Additionally, the self-designed fracture recording system successfully captured the complete process of pipeline failure, crack initiation, ductile propagation, and arrest. The crack tip opening angle (<em>CTOA</em>) fluctuated within 14.3°–21.2° along the propagation path and showed a gradual decreasing trend, while the crack propagation velocity first increased, maintained a stable phase, and then decreased. Notably, a higher N<sub>2</sub> molar concentration led to a higher stable fracture velocity. This research provides critical experimental data and theoretical support for the safety design and fracture control of supercritical CO<sub>2</sub> pipelines in CCUS projects.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105741"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-08DOI: 10.1016/j.ijpvp.2026.105757
Tomoki Shinko , Naoki Miura , Masaki Nagai
For the long-term operation of a nuclear reactor, it is important to effectively use the limited number of surveillance test specimens for conducting additional surveillance tests. One of the expected solutions is the use of miniature C(T) (Mini-C(T)) specimens which can be fabricated from broken Charpy specimens. However, it is known that the evaluation of J-R curves using Mini-C(T) specimens may be affected by the difference in plastic constraint due to the specimen size. In this paper, a novel methodology of specimen size effect correction in J-R curve evaluation based on a bending-modified plastic constraint parameter QM has been proposed. To verify the applicability of the proposed method to Mini-C(T) specimen in RPV steels, the J-R tests on the two Japanese RPV steels SQV2A with different fracture toughness levels were conducted using Mini-C(T), 0.5T-C(T), and 1T-C(T) specimens. As a result of the tests, a specimen size effect of Mini-C(T) specimen on J-R curve was found in the SQV2A with higher fracture toughness. To calculate QM, finite element method analysis has been performed to estimate the crack opening stress distribution ahead of the crack tip during the test. QM increased with increasing normalized J-integral. Based on the relationship between QM and normalized J-integral, the proposed method successfully reduced the specimen size effect on the J-R curve of the tested materials. The proposed method is expected to be useful in case of a limited amount of material such as surveillance specimens because the method requires no tests other than Mini-C(T) specimen testing.
{"title":"Novel methodology of specimen size effect correction in J-R curve evaluation based on bending-modified Q parameter","authors":"Tomoki Shinko , Naoki Miura , Masaki Nagai","doi":"10.1016/j.ijpvp.2026.105757","DOIUrl":"10.1016/j.ijpvp.2026.105757","url":null,"abstract":"<div><div>For the long-term operation of a nuclear reactor, it is important to effectively use the limited number of surveillance test specimens for conducting additional surveillance tests. One of the expected solutions is the use of miniature C(T) (Mini-C(T)) specimens which can be fabricated from broken Charpy specimens. However, it is known that the evaluation of J-R curves using Mini-C(T) specimens may be affected by the difference in plastic constraint due to the specimen size. In this paper, a novel methodology of specimen size effect correction in J-R curve evaluation based on a bending-modified plastic constraint parameter <em>Q</em><sub><em>M</em></sub> has been proposed. To verify the applicability of the proposed method to Mini-C(T) specimen in RPV steels, the J-R tests on the two Japanese RPV steels SQV2A with different fracture toughness levels were conducted using Mini-C(T), 0.5T-C(T), and 1T-C(T) specimens. As a result of the tests, a specimen size effect of Mini-C(T) specimen on J-R curve was found in the SQV2A with higher fracture toughness. To calculate <em>Q</em><sub><em>M</em></sub>, finite element method analysis has been performed to estimate the crack opening stress distribution ahead of the crack tip during the test. <em>Q</em><sub><em>M</em></sub> increased with increasing normalized J-integral. Based on the relationship between <em>Q</em><sub><em>M</em></sub> and normalized J-integral, the proposed method successfully reduced the specimen size effect on the J-R curve of the tested materials. The proposed method is expected to be useful in case of a limited amount of material such as surveillance specimens because the method requires no tests other than Mini-C(T) specimen testing.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105757"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-06DOI: 10.1016/j.ijpvp.2026.105753
T. Koers , B. Magyar , C. Bödger , T. Tröster
The state of the art shows that PBF-LB/M offers great potential for pressure-loaded parts, with significant weight reductions and simultaneous optimization of flow resistance. This study is aimed at applying existing calculation methods for pressure-loaded parts to additively manufactured pipe structures, considering the two materials EN AC-43000 (3.2381, AlSi10Mg) and AISI 316L (1.4404, X2CrNiMo17-12-2). For this purpose, systematic tensile tests are carried out for both materials. In addition, a statistical evaluation is performed to determine the design-relevant strength characteristics with a survival probability Ps of 97.5 % for both materials in the as-built and heat-treated condition.
Pipe specimens are manufactured, half of which are heat treated, geometrically measured and then subjected to a burst pressure test to experimentally determine the failure-critical internal pressure. These results are compared with calculated burst pressures. The calculations are based on the application-relevant methods identified in this study, considering the strength values determined for the respective material condition. This comparison is used to assess the suitability of the calculation methods for additively manufactured pipe structures, based on the materials investigated.
{"title":"Analytical and experimental determination of the failure-critical pressure of pipe structures manufactured by PBF-LB/M","authors":"T. Koers , B. Magyar , C. Bödger , T. Tröster","doi":"10.1016/j.ijpvp.2026.105753","DOIUrl":"10.1016/j.ijpvp.2026.105753","url":null,"abstract":"<div><div>The state of the art shows that PBF-LB/M offers great potential for pressure-loaded parts, with significant weight reductions and simultaneous optimization of flow resistance. This study is aimed at applying existing calculation methods for pressure-loaded parts to additively manufactured pipe structures, considering the two materials EN AC-43000 (3.2381, AlSi10Mg) and AISI 316L (1.4404, X2CrNiMo17-12-2). For this purpose, systematic tensile tests are carried out for both materials. In addition, a statistical evaluation is performed to determine the design-relevant strength characteristics with a survival probability <em>P</em><sub>s</sub> of 97.5 % for both materials in the as-built and heat-treated condition.</div><div>Pipe specimens are manufactured, half of which are heat treated, geometrically measured and then subjected to a burst pressure test to experimentally determine the failure-critical internal pressure. These results are compared with calculated burst pressures. The calculations are based on the application-relevant methods identified in this study, considering the strength values determined for the respective material condition. This comparison is used to assess the suitability of the calculation methods for additively manufactured pipe structures, based on the materials investigated.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105753"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-08DOI: 10.1016/j.ijpvp.2026.105752
Dorina Siebert, Elena Maier, Christina Radlbeck, Martin Mensinger
The cover plate is a common structural detail in railway bridges, and its welds are particularly susceptible to fatigue cracking. This study investigates the fracture mechanics of cover plate welds, focusing on the stress intensity factor and geometry correction factor through numerical simulations. A simple plate model with a semi-elliptical surface crack is first used for validation, with a maximum deviation of about 4 %, confirming the accuracy of the finite element analysis. A comprehensive parametric study is then performed for two configurations: a cover plate detail without a web and a cover plate detail with a web. Key geometric parameters are systematically analyzed. The results show that smaller width and thickness ratios increase the stress intensity factors, making these configurations more critical for fatigue. Additionally, steeper weld slopes (1:2) result in higher stress intensities than shallower slopes (1:3), which are more favorable. The inclusion of a web significantly increases the geometry correction factor, resulting in higher crack propagation rates. The web restricts base plate bending and compressive stress relief at the weld toe, resulting in stress intensity increases of up to 63 % (1:2 slope) and 40 % (1:3 slope). Comparison with literature formulas shows that the FEA-based results of this study yield lower correction factors, suggesting that current design formulas may be conservative. To support practical applications, regression formulas for the geometry correction factor are developed that achieve high accuracy (R2 ≥ 0.9774) and provide a more accurate basis for fatigue assessment in welded cover plate details.
{"title":"Numerical investigation of stress intensity and geometry correction factors in welded cover plate details","authors":"Dorina Siebert, Elena Maier, Christina Radlbeck, Martin Mensinger","doi":"10.1016/j.ijpvp.2026.105752","DOIUrl":"10.1016/j.ijpvp.2026.105752","url":null,"abstract":"<div><div>The cover plate is a common structural detail in railway bridges, and its welds are particularly susceptible to fatigue cracking. This study investigates the fracture mechanics of cover plate welds, focusing on the stress intensity factor and geometry correction factor through numerical simulations. A simple plate model with a semi-elliptical surface crack is first used for validation, with a maximum deviation of about 4 %, confirming the accuracy of the finite element analysis. A comprehensive parametric study is then performed for two configurations: a cover plate detail without a web and a cover plate detail with a web. Key geometric parameters are systematically analyzed. The results show that smaller width and thickness ratios increase the stress intensity factors, making these configurations more critical for fatigue. Additionally, steeper weld slopes (1:2) result in higher stress intensities than shallower slopes (1:3), which are more favorable. The inclusion of a web significantly increases the geometry correction factor, resulting in higher crack propagation rates. The web restricts base plate bending and compressive stress relief at the weld toe, resulting in stress intensity increases of up to 63 % (1:2 slope) and 40 % (1:3 slope). Comparison with literature formulas shows that the FEA-based results of this study yield lower correction factors, suggesting that current design formulas may be conservative. To support practical applications, regression formulas for the geometry correction factor are developed that achieve high accuracy (R<sup>2</sup> ≥ 0.9774) and provide a more accurate basis for fatigue assessment in welded cover plate details.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"221 ","pages":"Article 105752"},"PeriodicalIF":3.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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