A. Fedorov, A. Zhitenev, D. Strekalovskaya, A. Kur
: The properties of duplex stainless steels (DSSs) depend on the ferrite–austenite ratio and on the contents of secondary phases. Therefore, it is necessary to control the volume fractions, morphologies, and distribution patterns of all phases. The phases in the samples were identified using thermodynamic modeling and scanning electron microscopy. Investigated specimens were obtained after different heat treatments, such as solution annealing and quenching from 1050 to 1250 °C to obtain different amounts of ferrite and annealing at 850 °C to precipitate the σ -phase. There-fore, a metallographic technique for assessing the phases in DSSs based on selective etching and subsequent analysis according to ASTM E 1245 was developed. It was shown that the developed method of quantitative analysis based on selective etching and metallographic assessment according to ASTM E 1245 allows obtaining much more accurate results compared to the proposed ASTM E 562 method, which correlates well with the XRD quantitative phase analysis.
双相不锈钢(DSSs)的性能取决于铁素体-奥氏体比和二次相的含量。因此，有必要控制各相的体积分数、形态和分布模式。利用热力学模型和扫描电镜对样品中的相进行了鉴定。试样经过固溶退火和1050 ~ 1250℃淬火得到不同数量的铁素体，850℃退火析出σ相。因此，根据ASTM E 1245开发了一种基于选择性蚀刻和后续分析的金相技术来评估DSSs中的相。结果表明，与ASTM E 562方法相比，基于ASTM E 1245的选择性蚀刻和金相评估的定量分析方法可以获得更准确的结果，并且与XRD定量相分析具有良好的相关性。
{"title":"Quantitative description of the microstructure of duplex stainless steels using selective etching","authors":"A. Fedorov, A. Zhitenev, D. Strekalovskaya, A. Kur","doi":"10.3390/IEC2M-09387","DOIUrl":"https://doi.org/10.3390/IEC2M-09387","url":null,"abstract":": The properties of duplex stainless steels (DSSs) depend on the ferrite–austenite ratio and on the contents of secondary phases. Therefore, it is necessary to control the volume fractions, morphologies, and distribution patterns of all phases. The phases in the samples were identified using thermodynamic modeling and scanning electron microscopy. Investigated specimens were obtained after different heat treatments, such as solution annealing and quenching from 1050 to 1250 °C to obtain different amounts of ferrite and annealing at 850 °C to precipitate the σ -phase. There-fore, a metallographic technique for assessing the phases in DSSs based on selective etching and subsequent analysis according to ASTM E 1245 was developed. It was shown that the developed method of quantitative analysis based on selective etching and metallographic assessment according to ASTM E 1245 allows obtaining much more accurate results compared to the proposed ASTM E 562 method, which correlates well with the XRD quantitative phase analysis.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134436692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Davydov, A. Zhitenev, N. Devyaterikova, K. Laev
: High-strength oil country tubular goods (OCTG) like C110, according to standard API 5CT (yield strength at least 758 MPa), are subject to requirements in terms of mechanical and corrosion properties. In this work, we studied the influence of seamless tubes microstructure with a 177.8 mm diameter and 10.36 mm wall thickness of class С 110 high-strength steel to sulfide stress corrosion cracking (SSC) and sulfide stress corrosion cracking with low strain rates (SSRT). Tubes were obtained from continuous billets by screw piercing with preliminary quenching and temper-ing. It was established that cracking during the tests always begins from the inner surface of the tube. Rough segregation bands were found on the inner tube surface, which occupies about a third of the thickness. It is shown that the SSRT assessment technique allows to estimate the threshold value of the resistance.
{"title":"Influence of structural heterogeneity of high-strength OCTG tubes on sulfide corrosion cracking resistance","authors":"A. Davydov, A. Zhitenev, N. Devyaterikova, K. Laev","doi":"10.3390/IEC2M-09386","DOIUrl":"https://doi.org/10.3390/IEC2M-09386","url":null,"abstract":": High-strength oil country tubular goods (OCTG) like C110, according to standard API 5CT (yield strength at least 758 MPa), are subject to requirements in terms of mechanical and corrosion properties. In this work, we studied the influence of seamless tubes microstructure with a 177.8 mm diameter and 10.36 mm wall thickness of class С 110 high-strength steel to sulfide stress corrosion cracking (SSC) and sulfide stress corrosion cracking with low strain rates (SSRT). Tubes were obtained from continuous billets by screw piercing with preliminary quenching and temper-ing. It was established that cracking during the tests always begins from the inner surface of the tube. Rough segregation bands were found on the inner tube surface, which occupies about a third of the thickness. It is shown that the SSRT assessment technique allows to estimate the threshold value of the resistance.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130331784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The quest for suitable reductants for the extraction of iron from ores at minimal energy requirements and maximum degree of metallization is attracting growing researchers’ attention. In the present work, an attempt is made to use non-contact charcoal in the reduction of run-off mine goethite ore at heating temperatures above 570oC. The reduction mechanism adopted is in accordance with Levenspiel’s relations for the shrinking core model. The first stage is concerned with the diffusion of gaseous reactant through the film surrounding the particle to the surface of the solid where Goethite hematite is reduced by CO from wood charcoal to magnetite (3Fe2O3 + CO → 2Fe2O3 + CO2). The second stage involves the penetration of a gaseous reactant through the blanket of ash to the surface of the unreacted core where magnetite is reduced to wustite (Fe3O4 + CO → 3FeO + CO2). The final stage is the reaction of the gaseous reactant with solid at the reaction surface, which is described by the stoichiometry equation where the product consists of fluid and solid (FeO + CO → Fe + CO2). This non-contact charcoal reduction approach is adopted to maximize the benefit of using CO/CO2 gases from charcoal for reduction without the need for beneficiation and concentration. The rate-controlling steps for the reduction kinetics of average particle size 5, 10, 15, and 20 mm at 570, 700, 800, 900, and 1000oC are studied after heat treatment of the ore-wood charcoal in activated carbon reactor at total reduction time of 40 minutes based on literature. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis are done to investigate the spectrometric phase change and metallic components of the ore sample after reduction, respectively. The average percentage metallic iron content of 56.6, 60.8, and 61.7% and degree of metallization of 91.62, 75.96, and 93.6% are achieved from the SEM/EDX analysis of the reduced ore sample at reduction temperature of 570, 800 and 1000oC, respectively. The sharp drop in the degree of metallization of the reduced ore samples is observed at intermediate temperatures 700, 800, 900oC of the reduction. This indicates the tendency of high carbon deposit at the wustite stage of the reduction process at the least temperature and residence time of 5700C and 10 minutes, respectively. This study demonstrates that diffusion through the ash layer is the controlling resistance of the overall reduction process.
{"title":"DETERMINATION OF THE REACTION RATE CONTROLLING RESISTANCE OF GOETHITE IRON ORE REDUCTION USING CO/CO2 GASES FROM WOOD CHARCOAL","authors":"J. Ogbezode, O. Ajide, O. Oluwole, O. Ofi","doi":"10.3390/IEC2M-09373","DOIUrl":"https://doi.org/10.3390/IEC2M-09373","url":null,"abstract":"The quest for suitable reductants for the extraction of iron from ores at minimal energy requirements and maximum degree of metallization is attracting growing researchers’ attention. In the present work, an attempt is made to use non-contact charcoal in the reduction of run-off mine goethite ore at heating temperatures above 570oC. The reduction mechanism adopted is in accordance with Levenspiel’s relations for the shrinking core model. The first stage is concerned with the diffusion of gaseous reactant through the film surrounding the particle to the surface of the solid where Goethite hematite is reduced by CO from wood charcoal to magnetite (3Fe2O3 + CO → 2Fe2O3 + CO2). The second stage involves the penetration of a gaseous reactant through the blanket of ash to the surface of the unreacted core where magnetite is reduced to wustite (Fe3O4 + CO → 3FeO + CO2). The final stage is the reaction of the gaseous reactant with solid at the reaction surface, which is described by the stoichiometry equation where the product consists of fluid and solid (FeO + CO → Fe + CO2). This non-contact charcoal reduction approach is adopted to maximize the benefit of using CO/CO2 gases from charcoal for reduction without the need for beneficiation and concentration. The rate-controlling steps for the reduction kinetics of average particle size 5, 10, 15, and 20 mm at 570, 700, 800, 900, and 1000oC are studied after heat treatment of the ore-wood charcoal in activated carbon reactor at total reduction time of 40 minutes based on literature. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis are done to investigate the spectrometric phase change and metallic components of the ore sample after reduction, respectively. The average percentage metallic iron content of 56.6, 60.8, and 61.7% and degree of metallization of 91.62, 75.96, and 93.6% are achieved from the SEM/EDX analysis of the reduced ore sample at reduction temperature of 570, 800 and 1000oC, respectively. The sharp drop in the degree of metallization of the reduced ore samples is observed at intermediate temperatures 700, 800, 900oC of the reduction. This indicates the tendency of high carbon deposit at the wustite stage of the reduction process at the least temperature and residence time of 5700C and 10 minutes, respectively. This study demonstrates that diffusion through the ash layer is the controlling resistance of the overall reduction process.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114443967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Smooth and notched mechanical components made of metals frequently experience repeated cyclic loads at different temperatures. Thus, low cycle fatigue (LCF) is considered the dominant failure mode for these components. Stainless steel (SS) is the most widely selected material by engineers owing to its outstanding mechanical and LCF and anti-corrosion properties. Moreover, a reliable estimation of the fatigue life is essential in order to preserve people’s safety in industries. In the present study, an evaluation of some of the commonly known low cycle fatigue life methodologies are performed for notched and un-notched samples made of 316L (N) SS at ambient and higher temperatures. For the notched samples, the elastic–plastic strains were firstly determined and then the fatigue lives were estimated for constant nominal strain amplitudes, varying from ±0.4% to ±0.8%. A comparison between the calculated fatigue lives and those obtained experimentally from the literature was made. Overall, some of the widely used fatigue life prediction methods for smooth specimens have resulted in unsafe estimations for applied strain amplitudes ranging from ±0.3% to ±1.0%, and those of the notched specimens were generally found to give strongly conservative predictions. To overcome this problem, attempts were made to suggest new parameters that can precisely assess the lifetimes of smooth samples, and a new equation was suggested for notched samples under both room and high temperatures.
{"title":"Numerical and Analytical Analysis of the Low Cycle Fatigue Behavior of Notched and Un-notched 316 L (N) Austenitic Stainless Steel Samples at Ambient and Elevated Temperatures","authors":"I. Abarkan, A. Khamlichi, R. Shamass","doi":"10.3390/IEC2M-09329","DOIUrl":"https://doi.org/10.3390/IEC2M-09329","url":null,"abstract":"Smooth and notched mechanical components made of metals frequently experience repeated cyclic loads at different temperatures. Thus, low cycle fatigue (LCF) is considered the dominant failure mode for these components. Stainless steel (SS) is the most widely selected material by engineers owing to its outstanding mechanical and LCF and anti-corrosion properties. Moreover, a reliable estimation of the fatigue life is essential in order to preserve people’s safety in industries. In the present study, an evaluation of some of the commonly known low cycle fatigue life methodologies are performed for notched and un-notched samples made of 316L (N) SS at ambient and higher temperatures. For the notched samples, the elastic–plastic strains were firstly determined and then the fatigue lives were estimated for constant nominal strain amplitudes, varying from ±0.4% to ±0.8%. A comparison between the calculated fatigue lives and those obtained experimentally from the literature was made. Overall, some of the widely used fatigue life prediction methods for smooth specimens have resulted in unsafe estimations for applied strain amplitudes ranging from ±0.3% to ±1.0%, and those of the notched specimens were generally found to give strongly conservative predictions. To overcome this problem, attempts were made to suggest new parameters that can precisely assess the lifetimes of smooth samples, and a new equation was suggested for notched samples under both room and high temperatures.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129952601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kovalev, E. Alekseeva, N. Shaposhnikov, D. Lyashenko
In the oil and gas industry the majority of equipment failure incidents are caused by corrosion. One of the effective methods for corrosion protection is usage of different coatings systems. The article presents the results of polymer powder coatings properties research that used to protect the inner wall of field pipelines. Autoclave tests were used for researching coatings properties. Autoclave studies consisted of decompression tests and HT/HP immersion tests in simulated environments. The studies were carried out in solutions containing CO2, H2S in the gas phase, as well as in the phases of combined composition. The liquid phase was 5% NaCl with different pH levels. The influence of pressure release time, exposure time, pressure release cyclicity and composition of test solution on the functional properties of the coating was studied. Systems based on polymer powder coatings were used as test samples. The work result is the clarification of the autoclave tests methodological features and the identification of factors affecting the results repeatability. Identical coating systems have been tested over a wide temperature range, showing signs of coating degradation as test temperatures increase. Also given an example of autoclave test usage as a method for detecting low quality application of paint system. The results of the work will be useful in planning a test program for the development of new anticorrosive internal pipe coatings.
{"title":"Investigation of factors influencing on the autoclave tests results of internal anticorrosive polymer coatings","authors":"M. Kovalev, E. Alekseeva, N. Shaposhnikov, D. Lyashenko","doi":"10.3390/iec2m-09262","DOIUrl":"https://doi.org/10.3390/iec2m-09262","url":null,"abstract":"In the oil and gas industry the majority of equipment failure incidents are caused by corrosion. One of the effective methods for corrosion protection is usage of different coatings systems. The article presents the results of polymer powder coatings properties research that used to protect the inner wall of field pipelines.\u0000Autoclave tests were used for researching coatings properties. Autoclave studies consisted of decompression tests and HT/HP immersion tests in simulated environments. The studies were carried out in solutions containing CO2, H2S in the gas phase, as well as in the phases of combined composition. The liquid phase was 5% NaCl with different pH levels. The influence of pressure release time, exposure time, pressure release cyclicity and composition of test solution on the functional properties of the coating was studied. Systems based on polymer powder coatings were used as test samples.\u0000The work result is the clarification of the autoclave tests methodological features and the identification of factors affecting the results repeatability. Identical coating systems have been tested over a wide temperature range, showing signs of coating degradation as test temperatures increase. Also given an example of autoclave test usage as a method for detecting low quality application of paint system. The results of the work will be useful in planning a test program for the development of new anticorrosive internal pipe coatings.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132003710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The chemical and physical routes are usually used to synthesize metal nanoparticles. However, the harmful effects on the environment and human health has turned scientists into finding greener methods. We have developed the novel green method for the synthesis of flower Pd nanoparticles based on the chitosan (CS) polymer. In this method, CS can work as a stabilizer, a shape-directing agent, and a size-controllable agent for the synthesis of these nanoparticles. This study provides pioneer evidence about the multifunctional roles of natural polymers in the preparation of metal nanoparticles. Deep and extensive studies should be conducted to explore the great benefits of natural polymers in the green synthesis of metal nanoparticles.
{"title":"The multifunctional roles of chitosan in the formation of flower-shaped palladium nanoparticles","authors":"Thi Tuong Vy Phan","doi":"10.3390/IEC2M-09256","DOIUrl":"https://doi.org/10.3390/IEC2M-09256","url":null,"abstract":"The chemical and physical routes are usually used to synthesize metal nanoparticles. However, the harmful effects on the environment and human health has turned scientists into finding greener methods. We have developed the novel green method for the synthesis of flower Pd nanoparticles based on the chitosan (CS) polymer. In this method, CS can work as a stabilizer, a shape-directing agent, and a size-controllable agent for the synthesis of these nanoparticles. This study provides pioneer evidence about the multifunctional roles of natural polymers in the preparation of metal nanoparticles. Deep and extensive studies should be conducted to explore the great benefits of natural polymers in the green synthesis of metal nanoparticles.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134645757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: The basic reliability concepts - parametric ALT plan, failure mechanism and design, acceleration factor, and sample size equation were used in the development of a parametric accel erated life testing method to assess the reliability quantitative test specifications (RQ) of mechanical systems subjected to repetitive stresses. To calculate the acceleration factor of the mechanical system, a generalized life-stress failure model with a new effort concept was derived and recommended. The new sample size equation with the acceleration factor also enabled the parametric ALT to quickly evaluate the expected lifetime. This new parametric ALT should help an engineer uncover the design parameters affecting reliability during the design pro-cess of the mechanical system. Consequently, it should help companies improve product reliability and avoid recalls due to the product failures in the field. As the improper design parameters in the design phase are experimentally identified by this new reliability design method, the mechanical system should improve in reliability as measured by the increase in lifetime, LB, and the reduction in failure rate, As a test case, two cases were studied: 1) failed reciprocating compressors of French-door refrigerators returned from the field and 2) the redesign of hinge kit system (HKS) in a refrigerator. After a tailored of parametric accelerated life testing, the mechanical systems such as compressor and hinge kit system (HKS) with corrective action plans were expected to achieve the lifetime target – B1 life 10 years.
{"title":"Reliability Design Of Mechanical Systems Such Subjected To Repetitive Stresses","authors":"S. Woo, D. O’Neal, S. M. Atnaw, M. M. Tulu","doi":"10.3390/IEC2M-09257","DOIUrl":"https://doi.org/10.3390/IEC2M-09257","url":null,"abstract":": The basic reliability concepts - parametric ALT plan, failure mechanism and design, acceleration factor, and sample size equation were used in the development of a parametric accel erated life testing method to assess the reliability quantitative test specifications (RQ) of mechanical systems subjected to repetitive stresses. To calculate the acceleration factor of the mechanical system, a generalized life-stress failure model with a new effort concept was derived and recommended. The new sample size equation with the acceleration factor also enabled the parametric ALT to quickly evaluate the expected lifetime. This new parametric ALT should help an engineer uncover the design parameters affecting reliability during the design pro-cess of the mechanical system. Consequently, it should help companies improve product reliability and avoid recalls due to the product failures in the field. As the improper design parameters in the design phase are experimentally identified by this new reliability design method, the mechanical system should improve in reliability as measured by the increase in lifetime, LB, and the reduction in failure rate, As a test case, two cases were studied: 1) failed reciprocating compressors of French-door refrigerators returned from the field and 2) the redesign of hinge kit system (HKS) in a refrigerator. After a tailored of parametric accelerated life testing, the mechanical systems such as compressor and hinge kit system (HKS) with corrective action plans were expected to achieve the lifetime target – B1 life 10 years.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115052993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cracking is a major problem for some types of steel during additive manufacturing. Non-equilibrium kinetics of rapid solidification and solid-solid phase transformations are critical in determining cracking susceptibility. Previous studies correlate hot cracking susceptibility to solidification sequence, and therefore composition, empirically. In this study, an Integrated Computational Materials Engineering (ICME) approach is used to provide a more mechanistic and quantitative understanding of hot cracking susceptibility of a number of steels in relation to the peritectic reaction and evolution of delta ferrite during solidification. In this presentation, the application of ICME and hot cracking susceptibility predictions to alloy design for additive manufacturing are discussed.
{"title":"Understanding hot cracking of steels during rapid solidification: an ICME approach","authors":"Fuyao Yan, Jia-Yi Yan, D. Linder","doi":"10.3390/IEC2M-09254","DOIUrl":"https://doi.org/10.3390/IEC2M-09254","url":null,"abstract":"Cracking is a major problem for some types of steel during additive manufacturing. Non-equilibrium kinetics of rapid solidification and solid-solid phase transformations are critical in determining cracking susceptibility. Previous studies correlate hot cracking susceptibility to solidification sequence, and therefore composition, empirically. In this study, an Integrated Computational Materials Engineering (ICME) approach is used to provide a more mechanistic and quantitative understanding of hot cracking susceptibility of a number of steels in relation to the peritectic reaction and evolution of delta ferrite during solidification. In this presentation, the application of ICME and hot cracking susceptibility predictions to alloy design for additive manufacturing are discussed.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"328 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123401144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Ferraris, G. Ubertalli, A. Santostefano, A. Barbato
Low density, high specific stiffness and impact energy/vibration absorption ability make Al-based metal foams as promising materials in application for which lightweight, and energy/vibration absorption are crucial. The scientific literature documents an increasing interest in this topic (published papers rise from 100/year to 600/year in the last 20 years) and also industrial applications are emerging. In this context Al-based foams can be extremely interesting as cores in cast components in order to improve their properties and simplify their technological processes (no removal/recycling of traditional sand cores). However, both in the scientific literature and in technological application, this topic is still poorly explored (few paper/year, less than 10 patents). The published works include few details and characterizations and almost no solutions are discussed for the overcoming of criticism. In this context the present research considers and compare different foams, analyze both the foams and the cast objects, individuates main issues and proposes new strategies for their overcoming. In the present work,Al-based metal foams, (Cymat foams and Havel Metal Foams in the form of bars of rectangular section), are inserted in gravity casting experiment of the Al-Si-Cu-Mg alloy. The foams have been fully characterized before and after insertion in casting: (porosity, cell wall and external skin thickness, microstructure, infiltration degree and the quality of the interface between the foam core and the dense cast shell have been investigated by means of optical microscopy and Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS)). The analyses evidenced that a continuous and thick external skin protect the foam from infiltration by molten metal preserving the initial porosity and insert shape. A detailed analysis of the foam external skin (absent in the published literature) highlight that the composition of this external skin is crucial for the obtainment of a good joining between the molten metal and the Al-foam core. In fact, the presence of Mg-oxides on the foam surface prevent the bonding and maintain a gap between the core and the shell. This point opens the opportunity to design innovative surface modifications of this external skin as promising strategies for the optimization of cast component with a foam core.
{"title":"Aluminum foams as permanent cores in casting","authors":"S. Ferraris, G. Ubertalli, A. Santostefano, A. Barbato","doi":"10.3390/IEC2M-09253","DOIUrl":"https://doi.org/10.3390/IEC2M-09253","url":null,"abstract":"Low density, high specific stiffness and impact energy/vibration absorption ability make Al-based metal foams as promising materials in application for which lightweight, and energy/vibration absorption are crucial. The scientific literature documents an increasing interest in this topic (published papers rise from 100/year to 600/year in the last 20 years) and also industrial applications are emerging. In this context Al-based foams can be extremely interesting as cores in cast components in order to improve their properties and simplify their technological processes (no removal/recycling of traditional sand cores). However, both in the scientific literature and in technological application, this topic is still poorly explored (few paper/year, less than 10 patents). The published works include few details and characterizations and almost no solutions are discussed for the overcoming of criticism. In this context the present research considers and compare different foams, analyze both the foams and the cast objects, individuates main issues and proposes new strategies for their overcoming. \u0000In the present work,Al-based metal foams, (Cymat foams and Havel Metal Foams in the form of bars of rectangular section), are inserted in gravity casting experiment of the Al-Si-Cu-Mg alloy. The foams have been fully characterized before and after insertion in casting: (porosity, cell wall and external skin thickness, microstructure, infiltration degree and the quality of the interface between the foam core and the dense cast shell have been investigated by means of optical microscopy and Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS)). \u0000The analyses evidenced that a continuous and thick external skin protect the foam from infiltration by molten metal preserving the initial porosity and insert shape. A detailed analysis of the foam external skin (absent in the published literature) highlight that the composition of this external skin is crucial for the obtainment of a good joining between the molten metal and the Al-foam core. In fact, the presence of Mg-oxides on the foam surface prevent the bonding and maintain a gap between the core and the shell. This point opens the opportunity to design innovative surface modifications of this external skin as promising strategies for the optimization of cast component with a foam core.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133616929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Kaldre, M. Milgrāvis, A. Bojarevičs, T. Beinerts
The rise of metal additive manufacturing technology has increased the demand for high-performance alloys such as metal matrix composites (MMCs). The metallurgical production of MMCs remains a challenge. The nano-powder of dielectric particles does not mix well into the liquid metal because of several reasons. On a macroscopic level, the powder is rejected by the molten metal through buoyancy and surface tension forces. On a microscopic level, the particles are held together by Van der Waals forces forming particle agglomerates. Our research strategy is to address these issues separately in two steps. We are investigating an electromagnetically assisted MMC casting method for the production of particle-strengthened, directionally solidified aluminum alloys. In the first step, nanoparticles are mixed into melt while it is in a semi-solid state by efficient permanent magnet stirrers. Then, the alloy is subjected to ultrasound treatment for fine particle dispersion. Semi-continuous casting of MMC is used to obtain material for additive manufacturing process. Material is cast in 6–20 mm rods by a direct chill casting method and can be made into wire with the application of wire-feed additive manufacturing. We investigate the possibility of improving Al alloy SiC composite material properties by applying electromagnetic interactions during solidification. Electric current and a moderate static magnetic field (0.1–0.5 T) creates melt convection in mushy zone. Such interaction enhances heat and mass transfer near the solidification interface and hinders the re-agglomeration of the added particles.
{"title":"Electromagnetic processing during directional solidification of particle strengthened Aluminum alloys for additive manufacturing","authors":"I. Kaldre, M. Milgrāvis, A. Bojarevičs, T. Beinerts","doi":"10.3390/iec2m-09255","DOIUrl":"https://doi.org/10.3390/iec2m-09255","url":null,"abstract":"The rise of metal additive manufacturing technology has increased the demand for high-performance alloys such as metal matrix composites (MMCs). The metallurgical production of MMCs remains a challenge. The nano-powder of dielectric particles does not mix well into the liquid metal because of several reasons. On a macroscopic level, the powder is rejected by the molten metal through buoyancy and surface tension forces. On a microscopic level, the particles are held together by Van der Waals forces forming particle agglomerates. Our research strategy is to address these issues separately in two steps. We are investigating an electromagnetically assisted MMC casting method for the production of particle-strengthened, directionally solidified aluminum alloys. In the first step, nanoparticles are mixed into melt while it is in a semi-solid state by efficient permanent magnet stirrers. Then, the alloy is subjected to ultrasound treatment for fine particle dispersion. Semi-continuous casting of MMC is used to obtain material for additive manufacturing process. Material is cast in 6–20 mm rods by a direct chill casting method and can be made into wire with the application of wire-feed additive manufacturing. We investigate the possibility of improving Al alloy SiC composite material properties by applying electromagnetic interactions during solidification. Electric current and a moderate static magnetic field (0.1–0.5 T) creates melt convection in mushy zone. Such interaction enhances heat and mass transfer near the solidification interface and hinders the re-agglomeration of the added particles.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124840989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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