Pub Date : 2023-11-10DOI: 10.1080/09603409.2023.2281111
Jingwei Zhang, Zhicheng Li, Li Lin, Kanglin Liu
ABSTRACTThe high-temperature mechanical properties of 310S stainless steel were investigated by uniaxial tensile tests and small punch tests at the temperature from 20℃ to 600℃, and the relationship between the mechanical properties (σYS ,σUTS) and the characteristic loads (Fy, Fm) was established. The results revealed that with increasing temperature, the mechanical properties of 310S decrease, and the characteristic loads obtained by Fy_Mao, Fy_EN and Fy_E3205 are more appropriate for determining the yield strength of materials at high temperatures particularly for Fy_E3205. The fracture pattern observed in the SPT specimens indicated a mixed tough-brittle fracture accompanied by the characteristics of cleavage fracture. Additionally, the ultimate tensile strength of the material and the maximum load Fm increased slightly at 400 ℃ compared to 300 ℃ due to the precipitation of a large number of granular carbides and the increase in the grain size.KEYWORDS: 310s steelSmall punch testHigh temperatureMechanical propertiesFracture Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThe work was supported by the National Natural Science Foundation of China (No.51705079), Natural Science Foundation of Fujian Province (No.2018J01767), Open Fund of Fujian Key Laboratory of Energy Measurement（Fujian Metrology Institute） (NYJL-KFKT-2022-02).
{"title":"High-temperature mechanical properties evaluation of 310S stainless steel","authors":"Jingwei Zhang, Zhicheng Li, Li Lin, Kanglin Liu","doi":"10.1080/09603409.2023.2281111","DOIUrl":"https://doi.org/10.1080/09603409.2023.2281111","url":null,"abstract":"ABSTRACTThe high-temperature mechanical properties of 310S stainless steel were investigated by uniaxial tensile tests and small punch tests at the temperature from 20℃ to 600℃, and the relationship between the mechanical properties (σYS ,σUTS) and the characteristic loads (Fy, Fm) was established. The results revealed that with increasing temperature, the mechanical properties of 310S decrease, and the characteristic loads obtained by Fy_Mao, Fy_EN and Fy_E3205 are more appropriate for determining the yield strength of materials at high temperatures particularly for Fy_E3205. The fracture pattern observed in the SPT specimens indicated a mixed tough-brittle fracture accompanied by the characteristics of cleavage fracture. Additionally, the ultimate tensile strength of the material and the maximum load Fm increased slightly at 400 ℃ compared to 300 ℃ due to the precipitation of a large number of granular carbides and the increase in the grain size.KEYWORDS: 310s steelSmall punch testHigh temperatureMechanical propertiesFracture Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThe work was supported by the National Natural Science Foundation of China (No.51705079), Natural Science Foundation of Fujian Province (No.2018J01767), Open Fund of Fujian Key Laboratory of Energy Measurement（Fujian Metrology Institute） (NYJL-KFKT-2022-02).","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135137749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-09DOI: 10.1080/09603409.2023.2278833
K. Kettler, A. Klenk, S. Weihe
ABSTRACTThe design and operation of conventional power plant components is affected by load changes, with the balancing of renewable energy generation leading to an increase in warm and hot starts. Essential parts of these power plant components are flanges e.g. connecting pipes and turbine housings. While being structural rather simple, many influences affect the functionality of these flanges, like the high-temperature behaviour of the bolt material or the temperature distribution in the components. This paper presents parts of a recently finished research project on different influences on the relaxation behaviour of flanges. To investigate the influence of the bolt material, tests were carried out on a model of an IP turbine flange using martensitic X12CrMoWVNbN10-1-1 and nickel-based Ni80A bolts. Each tests included 2000 h of steady state and 3000 h of transient load with a retightening of the bolts after 1500 h. Exemplary relaxation tests on the X12 material provide additional information towards the observed behaviour in the flange tests.KEYWORDS: Stress relaxationcreepturbine flangetransient loadsretightening of boltscomponent testhigh temperature testing AcknowledgmentsThe presented results were obtained at MPA Stuttgart within a research project carried out in the industrial collective research programme (IGF No. 20088 N). It was supported by the Federal Ministry for Economic Affairs and Climate Action (BMWK) through the AiF (German Federation of Industrial Research Associations eV) based on a decision taken by the German Bundestag. The authors would also like to thank the research partners from the IfW Technical University of Darmstadt and the experts from member companies especially from GE Power GmbH, Siemens Energy Global GmbH & Co. KG und MAN Energy Solutions SE for their contributions in the project working group and the provision of various benefits in kind.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the AiF Projekt [20088 N].
{"title":"Experimental investigations on a model of a power plant flange under steady state and transient load","authors":"K. Kettler, A. Klenk, S. Weihe","doi":"10.1080/09603409.2023.2278833","DOIUrl":"https://doi.org/10.1080/09603409.2023.2278833","url":null,"abstract":"ABSTRACTThe design and operation of conventional power plant components is affected by load changes, with the balancing of renewable energy generation leading to an increase in warm and hot starts. Essential parts of these power plant components are flanges e.g. connecting pipes and turbine housings. While being structural rather simple, many influences affect the functionality of these flanges, like the high-temperature behaviour of the bolt material or the temperature distribution in the components. This paper presents parts of a recently finished research project on different influences on the relaxation behaviour of flanges. To investigate the influence of the bolt material, tests were carried out on a model of an IP turbine flange using martensitic X12CrMoWVNbN10-1-1 and nickel-based Ni80A bolts. Each tests included 2000 h of steady state and 3000 h of transient load with a retightening of the bolts after 1500 h. Exemplary relaxation tests on the X12 material provide additional information towards the observed behaviour in the flange tests.KEYWORDS: Stress relaxationcreepturbine flangetransient loadsretightening of boltscomponent testhigh temperature testing AcknowledgmentsThe presented results were obtained at MPA Stuttgart within a research project carried out in the industrial collective research programme (IGF No. 20088 N). It was supported by the Federal Ministry for Economic Affairs and Climate Action (BMWK) through the AiF (German Federation of Industrial Research Associations eV) based on a decision taken by the German Bundestag. The authors would also like to thank the research partners from the IfW Technical University of Darmstadt and the experts from member companies especially from GE Power GmbH, Siemens Energy Global GmbH & Co. KG und MAN Energy Solutions SE for their contributions in the project working group and the provision of various benefits in kind.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the AiF Projekt [20088 N].","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135290867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-09DOI: 10.1080/09603409.2023.2268334
M. Schwienheer, F. Kolzow
ABSTRACTFor the service life calculation of high-temperature components the knowledge of the creep behaviour of the materials used remain essential. Over decades, many methods have been developed for extrapolating creep rupture strengths. The challenge with these Creep Rupture Data Assessments (CRDAs), however, always remains evaluating the predictive accuracy of creep life. New computer-aided calculation methods allow the use of extensive data on the casts and other experimental data, as well as the application of probabilistic methods. Within the ECCC, software tools are being developed that both leverage the capabilities of new powerful computer-aided computational methods and allow for simultaneous assessment with post-assessment testing in accordance with ECCC recommendations. The authors would like to point out that despite all available tools and guidelines, the expertise and experience of the assessor is an indispensable guarantor for a reliable evaluation.KEYWORDS: Creepcreep rupture dataassessmentpost assessment testsmaximum likelihoodprobabilistic lifetime model AcknowledgmentsThe authors would like to thank the ECCC for its technical and financial support. “So long, and thanks for all the fish” [39].Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the ECCC European Creep Collaborative Committee.
{"title":"Creep rupture data assessment – new uncertain challenges require new uncertain answers","authors":"M. Schwienheer, F. Kolzow","doi":"10.1080/09603409.2023.2268334","DOIUrl":"https://doi.org/10.1080/09603409.2023.2268334","url":null,"abstract":"ABSTRACTFor the service life calculation of high-temperature components the knowledge of the creep behaviour of the materials used remain essential. Over decades, many methods have been developed for extrapolating creep rupture strengths. The challenge with these Creep Rupture Data Assessments (CRDAs), however, always remains evaluating the predictive accuracy of creep life. New computer-aided calculation methods allow the use of extensive data on the casts and other experimental data, as well as the application of probabilistic methods. Within the ECCC, software tools are being developed that both leverage the capabilities of new powerful computer-aided computational methods and allow for simultaneous assessment with post-assessment testing in accordance with ECCC recommendations. The authors would like to point out that despite all available tools and guidelines, the expertise and experience of the assessor is an indispensable guarantor for a reliable evaluation.KEYWORDS: Creepcreep rupture dataassessmentpost assessment testsmaximum likelihoodprobabilistic lifetime model AcknowledgmentsThe authors would like to thank the ECCC for its technical and financial support. “So long, and thanks for all the fish” [39].Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the ECCC European Creep Collaborative Committee.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135291338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACTA practical procedure for predicting the remaining creep-rupture life of in-service boiler pipes under their operating conditions is proposed and discussed in this study. Tests were conducted on a coupon obtained using electric discharge sampling equipment from the outer surface of an in-service boiler pipe of modified 9Cr-1Mo steel. An ultra-miniature creep (UMC) specimen machined from the coupon was employed for the tensile creep test. Focusing on an iso–stress approach that has potential for the remaining life prediction using a limited test data, its suitability has been discussed. Test results indicate that the iso–stress approach can be applied to predict the remaining creep-rupture life using the UMC testing method with high accuracy. Furthermore, an examination of the high-temperature oxidation resistance of the UMC specimen indicated that oxidation had little influence on the rupture time.KEYWORDS: In-service pipingmodified 9Cr-1Mo steelremaining creep life predictionultra-miniature specimeniso–stress approachLarson–Miller parameterMonkman–Grant relationshiphigh-temperature oxidation Disclosure statementNo potential conflict of interest was reported by the author(s).
{"title":"Practical application of an ultra-miniature creep test to the remaining creep-rupture life prediction using an iso–stress approach for in-service boiler piping of modified 9Cr-1Mo steel","authors":"Hirohide Nakatsuka, Chiaki Hisaka, Kazukiyo Takahashi, Akito Nitta, Masatsugu Yaguchi","doi":"10.1080/09603409.2023.2278361","DOIUrl":"https://doi.org/10.1080/09603409.2023.2278361","url":null,"abstract":"ABSTRACTA practical procedure for predicting the remaining creep-rupture life of in-service boiler pipes under their operating conditions is proposed and discussed in this study. Tests were conducted on a coupon obtained using electric discharge sampling equipment from the outer surface of an in-service boiler pipe of modified 9Cr-1Mo steel. An ultra-miniature creep (UMC) specimen machined from the coupon was employed for the tensile creep test. Focusing on an iso–stress approach that has potential for the remaining life prediction using a limited test data, its suitability has been discussed. Test results indicate that the iso–stress approach can be applied to predict the remaining creep-rupture life using the UMC testing method with high accuracy. Furthermore, an examination of the high-temperature oxidation resistance of the UMC specimen indicated that oxidation had little influence on the rupture time.KEYWORDS: In-service pipingmodified 9Cr-1Mo steelremaining creep life predictionultra-miniature specimeniso–stress approachLarson–Miller parameterMonkman–Grant relationshiphigh-temperature oxidation Disclosure statementNo potential conflict of interest was reported by the author(s).","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135341751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACTC276 superalloy is considered as a potential structural material for advanced nuclear reactor with good mechanical properties and corrosion resistance. High-temperature creep behaviour of C276 alloy was investigated in the temperature range of 650°C–700°C and at stresses of 140–430 MPa. A linear relationship was fitted between stress and minimum creep rate in the logarithmic coordinate system. The rupture time is analysed for life prediction in terms of isotherm extrapolation method, Monkman–Grant relation, and Larson–Miller parameter method, respectively. The isochronous stress–strain curves as a means of representing stress–strain–time relations under creep conditions were established by the parameter method. The fracture surface morphology of ruptured specimens was characterised by a scanning electron microscope to elucidate the failure mechanism.KEYWORDS: Ni-Mo-Cr superalloycreep rupturelife predictionisochronous stress–strain curve AcknowledgmentsThis work was supported by the National Natural Science Foundation of China (Grant nos. 52071330, 51901241), the Research Project of Shanghai Science and Technology Commission (19DZ2200300), the National Key Research and Development Program (Grant no. 2021YFB3700605), the Young Potential Program of Shanghai Institute of Applied Physics, Chinese Academy of Sciences and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA02004210).Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThe work was supported by the National Natural Science Foundation of China [52071330]; National Natural Science Foundation of China [51901241]; the Strategic Priority Research Program of the Chinese Academy of Sciences [XDA02004210]; Research Project of Shanghai Science and Technology Commission [19DZ2200300]; the National Key Research and Development Program [2021YFB3700605].
{"title":"Study on creep characteristics and the isochronous stress–strain curve of Ni-Cr-Mo superalloy","authors":"Guangcheng Fan, Guangzhou Yuan, Wanxia Wang, Songlin Wang, Jianxiong Zhang, Yanyan Jia, Jiamin Wang, Yanling Lu","doi":"10.1080/09603409.2023.2277565","DOIUrl":"https://doi.org/10.1080/09603409.2023.2277565","url":null,"abstract":"ABSTRACTC276 superalloy is considered as a potential structural material for advanced nuclear reactor with good mechanical properties and corrosion resistance. High-temperature creep behaviour of C276 alloy was investigated in the temperature range of 650°C–700°C and at stresses of 140–430 MPa. A linear relationship was fitted between stress and minimum creep rate in the logarithmic coordinate system. The rupture time is analysed for life prediction in terms of isotherm extrapolation method, Monkman–Grant relation, and Larson–Miller parameter method, respectively. The isochronous stress–strain curves as a means of representing stress–strain–time relations under creep conditions were established by the parameter method. The fracture surface morphology of ruptured specimens was characterised by a scanning electron microscope to elucidate the failure mechanism.KEYWORDS: Ni-Mo-Cr superalloycreep rupturelife predictionisochronous stress–strain curve AcknowledgmentsThis work was supported by the National Natural Science Foundation of China (Grant nos. 52071330, 51901241), the Research Project of Shanghai Science and Technology Commission (19DZ2200300), the National Key Research and Development Program (Grant no. 2021YFB3700605), the Young Potential Program of Shanghai Institute of Applied Physics, Chinese Academy of Sciences and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA02004210).Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThe work was supported by the National Natural Science Foundation of China [52071330]; National Natural Science Foundation of China [51901241]; the Strategic Priority Research Program of the Chinese Academy of Sciences [XDA02004210]; Research Project of Shanghai Science and Technology Commission [19DZ2200300]; the National Key Research and Development Program [2021YFB3700605].","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135341881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-08DOI: 10.1080/09603409.2023.2276996
D. Baraldi, K.-F Nilsson, S. Holmström, I. Simonovski
A uniaxial creep model that describes creep over a wide stress range was developed for P91 steel using an artificial neural network (ANN). The training dataset was based on measurements from uniaxial creep tests and information derived from a combination of the logistic creep strain prediction and the Wilshire models. The ANN model reproduces the training dataset with high accuracy (R2 = 0.975; RMSE (Root Mean Square Error) = 0.19). The model can be easily implemented in finite element analysis (FEA) codes since it provides an analytical expression of the true creep rate as a function of temperature, true stress and true creep strain. In FEA simulations under the same conditions as the training dataset, the model provides times to rupture and minimum creep rates very close to those in the training dataset. The model can be adapted for heats with different properties from the average behaviour of the training dataset by means of a stress-scaling factor.
{"title":"Development of a P91 uniaxial creep model for a wide stress range with an artificial neural network","authors":"D. Baraldi, K.-F Nilsson, S. Holmström, I. Simonovski","doi":"10.1080/09603409.2023.2276996","DOIUrl":"https://doi.org/10.1080/09603409.2023.2276996","url":null,"abstract":"A uniaxial creep model that describes creep over a wide stress range was developed for P91 steel using an artificial neural network (ANN). The training dataset was based on measurements from uniaxial creep tests and information derived from a combination of the logistic creep strain prediction and the Wilshire models. The ANN model reproduces the training dataset with high accuracy (R2 = 0.975; RMSE (Root Mean Square Error) = 0.19). The model can be easily implemented in finite element analysis (FEA) codes since it provides an analytical expression of the true creep rate as a function of temperature, true stress and true creep strain. In FEA simulations under the same conditions as the training dataset, the model provides times to rupture and minimum creep rates very close to those in the training dataset. The model can be adapted for heats with different properties from the average behaviour of the training dataset by means of a stress-scaling factor.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135341879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We demonstrate a dislocation density-based crystal plasticity (CP) model approach for simulating mesoscale deformation and damage. The existing CP framework is extended to be compatible with the oxygen-free phosphorous copper microstructure that is the focus of this study. The key aim is to introduce relevant plastic deformation mechanisms and to develop a failure model capable of depicting creep damage in the material. The effect of local variations in material is evaluated, and the model response is compared with experiments and characterisation. The basis of this work is CP material modelling, including grain orientation and size, obtained using electron backscatter diffraction and experimental test data of real relaxation test specimens. This will yield a realistic description of texture and grain shape and, ultimately, accurate stress–strain response at the microstructural level for further evaluation of performance with respect to material creep(−fatigue) damage.
{"title":"Crystal plasticity model for creep and relaxation deformation of OFP copper","authors":"Tom. Andersson, Matti. Lindroos, Rami. Pohja, Abhishek. Biswas, Supriya. Nandy, Janne. Pakarinen, Juhani. Rantala","doi":"10.1080/09603409.2023.2278232","DOIUrl":"https://doi.org/10.1080/09603409.2023.2278232","url":null,"abstract":"We demonstrate a dislocation density-based crystal plasticity (CP) model approach for simulating mesoscale deformation and damage. The existing CP framework is extended to be compatible with the oxygen-free phosphorous copper microstructure that is the focus of this study. The key aim is to introduce relevant plastic deformation mechanisms and to develop a failure model capable of depicting creep damage in the material. The effect of local variations in material is evaluated, and the model response is compared with experiments and characterisation. The basis of this work is CP material modelling, including grain orientation and size, obtained using electron backscatter diffraction and experimental test data of real relaxation test specimens. This will yield a realistic description of texture and grain shape and, ultimately, accurate stress–strain response at the microstructural level for further evaluation of performance with respect to material creep(−fatigue) damage.","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135634275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.1080/09603409.2023.2276995
ARMAN Rabieifar, M. REZA Afshar, HAMIDREZA Najafi
ABSTRACTThe effect of oxide scale and microstructural changes during 10, 20, and 40 hot corrosion cycles on the high-temperature tensile properties of Rene-80 superalloy at 950 °C was investigated. Due to the formation of micro-cracks and micro-voids, compressive stresses produced from Cr2O3 and NiO growth, and tensile stresses stemming from NiMoO4 transformation and Al internal oxidation, the oxide scale spalled. By increasing the hot corrosion cycles, UTS (Ultimate Tensile Strength) and El.% (Elongation) first decreased and then increased due to the propagation of intergranular vertical cracks from the oxide scale to the Rene-80 after 20 cycles. During hot corrosion cycles, YS increased due to a rise in the density of near-surface intergranular cracks close to the Rene-80/oxide scale interface resulting from micro-void linkage and γ′-depleted zone. Due to the high area fraction and the small average size of secondary γ′, UTS and YS were the highest and lowest after ten cycles, respectively.KEYWORDS: Rene-80 superalloyhot corrosionoxide scaletensile propertiesfracture surfaceγ' precipitate Disclosure statementNo potential conflict of interest was reported by the author(s).
{"title":"The effect of oxide scale and microstructural changes during cyclic hot corrosion on high-temperature tensile properties of Rene-80 superalloy","authors":"ARMAN Rabieifar, M. REZA Afshar, HAMIDREZA Najafi","doi":"10.1080/09603409.2023.2276995","DOIUrl":"https://doi.org/10.1080/09603409.2023.2276995","url":null,"abstract":"ABSTRACTThe effect of oxide scale and microstructural changes during 10, 20, and 40 hot corrosion cycles on the high-temperature tensile properties of Rene-80 superalloy at 950 °C was investigated. Due to the formation of micro-cracks and micro-voids, compressive stresses produced from Cr2O3 and NiO growth, and tensile stresses stemming from NiMoO4 transformation and Al internal oxidation, the oxide scale spalled. By increasing the hot corrosion cycles, UTS (Ultimate Tensile Strength) and El.% (Elongation) first decreased and then increased due to the propagation of intergranular vertical cracks from the oxide scale to the Rene-80 after 20 cycles. During hot corrosion cycles, YS increased due to a rise in the density of near-surface intergranular cracks close to the Rene-80/oxide scale interface resulting from micro-void linkage and γ′-depleted zone. Due to the high area fraction and the small average size of secondary γ′, UTS and YS were the highest and lowest after ten cycles, respectively.KEYWORDS: Rene-80 superalloyhot corrosionoxide scaletensile propertiesfracture surfaceγ' precipitate Disclosure statementNo potential conflict of interest was reported by the author(s).","PeriodicalId":49877,"journal":{"name":"Materials at High Temperatures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-19DOI: 10.1080/09603409.2023.2261780
Daniel Osorio, Arianna Gotti, Florian Kauffmann, Andreas Klenk, Stefan Weihe
ABSTRACTThe aim of the paper is to investigate experimentally the fatigue and creep-fatigue material behaviour of improved materials and welded joints for the application in flexible future power plants. These materials promise a reduction in manufacturing costs as well as an increase in flexibility by providing enhanced creep strength thorugh a wall thickness reduction. At the temperature range between 500°C −550°C, the investigation focusses on the creep and low-cycle fatigue behaviour of dissimilar welded joints from conventional materials (bainitic and martensitic materials T24 and T92) to nickel-based alloys (A617B and HR6W) fabricated as tubes. At the temperature range between 700°C and 750°C, it focusses on the creep, low-cycle fatigue and creep-fatigue behaviour of similar and dissimilar welded joints from nickel-based alloys (A740H, A617B and A263) fabricated as tubes and as pipes. Metallographic investigations after testing provide support for understanding the influence of temperature, strain amplitude and dwell time on the microstructure change and the fatigue strength.KEYWORDS: Creepfatiguecreep-fatiguemartensitic/bainitic steelsnickel-based-alloyweld jointstubepipe Additional Notes to AuthorsDo you wish your paper to be submitted to Materials at High Temperatures … … … … … … Yes/NoThose papers accepted for inclusion in the MHT Journal will only appear in the conference proceedings as an abstract with reference to the full paper in the relevant edition of the Journal.An abstract book will be included within the delegate pack as below. You are invited to include a photo of the main author/presenter, to aid networking at the conference. If you prefer not to supply a photo we will happily include the abstract without a photo.Any questions relating to paper/presentation and submission to paper please contact the Chair of the Scientific Committee Dr Augusto Di Gianfrancesco, a.digianfrancesco@libero.it.Any questions relating to the organisation of the conference, registration or administration please contact the Chair of the Organising Committee Dr Peter Barnard, peter.barnard@mpiuk.comAcknowledgmentsThe results presented in this paper were generated within the European Research Project “Ni-based alloys for Operation of 725°C Power Plants, acronym NIBALO725“. This project has received funding from the Research Fund for Coal and Steel under grant agreement No. 709976. The authors thank the project consortium for the fruitful discussion during the project meetings, especially Special Metals for providing the A740H material (tube and pipe) and GE Power GmbH (former GE Boiler Deutschland GmbH) for the fabrication of the pipe and tube weldments.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis work was supported by the Research Fund for Coal and Steel [709976].
摘要本文的目的是对未来柔性电站中应用的改进材料和焊接接头的疲劳和蠕变疲劳材料性能进行实验研究。这些材料有望降低制造成本，并通过减少壁厚提供增强的蠕变强度来增加灵活性。在500°C - 550°C的温度范围内，研究了从传统材料(贝氏体和马氏体材料T24和T92)到管状镍基合金(A617B和HR6W)的不同焊接接头的蠕变和低周疲劳行为。在700°C至750°C的温度范围内，重点研究了由镍基合金(A740H、A617B和A263)制成的管和管的相似和不同焊接接头的蠕变、低周疲劳和蠕变疲劳行为。试验后的金相研究为了解温度、应变幅值和停留时间对组织变化和疲劳强度的影响提供了支持。关键词:蠕变疲劳蠕变疲劳马氏体/贝氏体钢-镍基合金焊接接头作者补充说明您是否希望将您的论文提交给高温材料... ... ... ... ... ...是/否那些被纳入MHT期刊的论文将仅作为参考期刊相关版本全文的摘要出现在会议论文集中。一个摘要书将包括在委托包如下。我们邀请您附上主要作者/演讲者的照片，以帮助在会议上建立网络。如果您不愿意提供照片，我们将很高兴地包括没有照片的摘要。任何关于论文/演示和提交论文的问题请联系科学委员会主席auguto Di Gianfrancesco博士，a.digianfrancesco@libero.it.Any关于会议组织，注册或管理的问题请联系组织委员会主席Peter Barnard博士，peter.barnard@mpiuk.comAcknowledgmentsThe本文中提出的结果是在欧洲研究项目“用于725°C发电厂运行的镍基合金，缩写为NIBALO725”中产生的。本项目已获得煤炭和钢铁研究基金资助，资助协议号为709976。作者感谢项目联合体在项目会议期间进行的富有成果的讨论，特别是特种金属公司提供的A740H材料(管和管)和GE Power GmbH(原GE Boiler Deutschland GmbH)制造的管和管焊接件。披露声明作者未报告潜在的利益冲突。本研究得到了煤炭和钢铁研究基金[709976]的支持。
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Pub Date : 2023-10-16DOI: 10.1080/09603409.2023.2268332
Mark Evans
A reliable means of assessing the accuracy of a creep model’s predictions is fundamental to safe power plant operation. This paper introduces a method of decomposing the mean absolute prediction error for such a purpose to overcome the limitations that are inherent in the traditional approach of squaring prediction errors to prevent over and underestimates of life offsetting each other. When this method is applied to 2.25Cr-1Mo steel and 316 H stainless steel, it was found that squared errors leads to overestimates of the average prediction error associated with a particular creep model, and it also dramatically underestimates the proportion of this error that is systematic in nature. These differences were more noticeable for 316 H stainless steel.
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