Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222551
Gleicon Roberto de Sousa Maior, Marcos Rogério do Nascimento
{"title":"Análise dos procedimentos de desenvolvimento de mina em uma pedreira de mármore na região de Itaoca - Distrito de Cachoeiro de Itapemirim - ES","authors":"Gleicon Roberto de Sousa Maior, Marcos Rogério do Nascimento","doi":"10.4322/2176-1523.20222551","DOIUrl":"https://doi.org/10.4322/2176-1523.20222551","url":null,"abstract":"","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70526485","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}
Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222727
Arthur Pinto Chave
This article presents a review of the evolution of the sorting process in recent years. The process is no longer exclusively dependent on optical properties. The old sorting practice and the modern equipment are described. Different properties such as shape, natural radiation, laser and X-ray fluorescence, gamma and infrared rays absorption, magnetic resonance used today are introduced. Analytical methods processed in real time are also used. The use of artificial intelligence, instrumentation and computation makes sorting today a very trustworthy and sophisticated separation method. It is performed dry. Its great limitation is processing capacity, but manufacturers are making efforts to overcome this limitation.
{"title":"Developments in separation by sorting","authors":"Arthur Pinto Chave","doi":"10.4322/2176-1523.20222727","DOIUrl":"https://doi.org/10.4322/2176-1523.20222727","url":null,"abstract":"This article presents a review of the evolution of the sorting process in recent years. The process is no longer exclusively dependent on optical properties. The old sorting practice and the modern equipment are described. Different properties such as shape, natural radiation, laser and X-ray fluorescence, gamma and infrared rays absorption, magnetic resonance used today are introduced. Analytical methods processed in real time are also used. The use of artificial intelligence, instrumentation and computation makes sorting today a very trustworthy and sophisticated separation method. It is performed dry. Its great limitation is processing capacity, but manufacturers are making efforts to overcome this limitation.","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70526659","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}
Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222746
Lucas Theisen, Sandra Raquel Kunst, Ana Caroline Viero Bianchin, Fernando Dal Pont Morisso, C. T. Oliveira
The critical factors that determine the application of titanium and its alloys for biomedical implants are its mechanical and chemical properties, followed by excellent corrosion resistance and biocompatibility. Thus, anodization has been used to favor the formation of porous surfaces that improve the osseointegration process in titanium, seeking properties that can stimulate the growth of newly formed bone. However, this process uses electrolytes based on hydrofluoric acid (HF), which is harmful to the health of the patient receiving the prosthesis. The aim of this study was to obtain a porous surface of titanium in F-free electrolytes. In this way, titanium samples were anodized in sulfuric acid electrolytes with and without hydrogen peroxide addition, in varying concentrations, in order to obtain a porous surface of titanium oxide. The growth of oxides was evaluated by means of anodizing transients and the samples obtained were analyzed by SEM. The samples showed the formation of porous oxides of nanometric dimensions. Therefore, this study shows an alternative for the formation of pores, without the use of HF-based electrolyte, with potential application in biomaterials.
{"title":"Anodização porosa de titânio em eletrólito livre de HF","authors":"Lucas Theisen, Sandra Raquel Kunst, Ana Caroline Viero Bianchin, Fernando Dal Pont Morisso, C. T. Oliveira","doi":"10.4322/2176-1523.20222746","DOIUrl":"https://doi.org/10.4322/2176-1523.20222746","url":null,"abstract":"The critical factors that determine the application of titanium and its alloys for biomedical implants are its mechanical and chemical properties, followed by excellent corrosion resistance and biocompatibility. Thus, anodization has been used to favor the formation of porous surfaces that improve the osseointegration process in titanium, seeking properties that can stimulate the growth of newly formed bone. However, this process uses electrolytes based on hydrofluoric acid (HF), which is harmful to the health of the patient receiving the prosthesis. The aim of this study was to obtain a porous surface of titanium in F-free electrolytes. In this way, titanium samples were anodized in sulfuric acid electrolytes with and without hydrogen peroxide addition, in varying concentrations, in order to obtain a porous surface of titanium oxide. The growth of oxides was evaluated by means of anodizing transients and the samples obtained were analyzed by SEM. The samples showed the formation of porous oxides of nanometric dimensions. Therefore, this study shows an alternative for the formation of pores, without the use of HF-based electrolyte, with potential application in biomaterials.","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70526945","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}
Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222617
T. B. Tavares, F. Costa, Marília Faria de Oliveira Caizer
Major improvements in new advanced high strength steels, especially related to microstructural features, have been made by the steel sector to access the trade-off between strength and ductility. In this context, the present study provides a detailed analysis of the microstructure of a cold rolled steel with a minimum tensile strength of 980 MPa, which possesses superior elongation when compared to other conceptions of steels from the same strength level. The annealing process was simulated in a Gleeble machine, and the microstructural characterization was done using optical and scanning electron microscopy, EBSD and XRD analysis. Austenite decomposition, using dilatometric test, and mechanical properties were also evaluated. The steel characterization revealed a microstructure consisting of ferrite matrix with martensite islands and retained austenite particles, in a fraction equivalent to that of conventional TRIP steels, dispersed throughout. The carbon content in the austenite, however, was less than 1.0% w/w, which results in a relatively low stability. Therefore, the increase in strain hardening capacity enabled by the deformation-induced transformation of austenite to martensite produces increased ductility during straining, distinguishing the analyzed material from other steels of the same strength level.
{"title":"Microstructure evaluation of an advanced high strength steel with superior results in terms of strength-ductility trade-off","authors":"T. B. Tavares, F. Costa, Marília Faria de Oliveira Caizer","doi":"10.4322/2176-1523.20222617","DOIUrl":"https://doi.org/10.4322/2176-1523.20222617","url":null,"abstract":"Major improvements in new advanced high strength steels, especially related to microstructural features, have been made by the steel sector to access the trade-off between strength and ductility. In this context, the present study provides a detailed analysis of the microstructure of a cold rolled steel with a minimum tensile strength of 980 MPa, which possesses superior elongation when compared to other conceptions of steels from the same strength level. The annealing process was simulated in a Gleeble machine, and the microstructural characterization was done using optical and scanning electron microscopy, EBSD and XRD analysis. Austenite decomposition, using dilatometric test, and mechanical properties were also evaluated. The steel characterization revealed a microstructure consisting of ferrite matrix with martensite islands and retained austenite particles, in a fraction equivalent to that of conventional TRIP steels, dispersed throughout. The carbon content in the austenite, however, was less than 1.0% w/w, which results in a relatively low stability. Therefore, the increase in strain hardening capacity enabled by the deformation-induced transformation of austenite to martensite produces increased ductility during straining, distinguishing the analyzed material from other steels of the same strength level.","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70526955","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}
Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222751
E. A. Duda, S. Soares, D. Buzzatti, G. Lemos, Tárique Hernandez Schneider, H. P. Cardoso, T. Falcade, A. Reguly
Friction-stir welding (FSW) is a well-known solid-state technology for manufacturing high-quality aluminum welds. However, corrosion may become an issue due to the changes in the microstructure within the stir zone, perhaps creating a local galvanic couple. In this work, AA 5083-O aluminum plates were joined by FSW, and corrosion analyzes were undertaken. Therefore, corrosion behavior was investigated using an immersion test, open circuit potential (OCP), and zero-resistance ammeter (ZRA) measurements. The stirred material was found to be more resistant to pitting nucleation than the AA5083-O alloy base material on immersion test and OCP analyzes. Nevertheless, deeper pits were more significant in the stirred material. The ZRA test showed similar results for both regions, indicating this system’s low galvanic couple effect.
{"title":"An investigation on galvanic corrosion in frictionstir-welded AA 5083 aluminum alloy","authors":"E. A. Duda, S. Soares, D. Buzzatti, G. Lemos, Tárique Hernandez Schneider, H. P. Cardoso, T. Falcade, A. Reguly","doi":"10.4322/2176-1523.20222751","DOIUrl":"https://doi.org/10.4322/2176-1523.20222751","url":null,"abstract":"Friction-stir welding (FSW) is a well-known solid-state technology for manufacturing high-quality aluminum welds. However, corrosion may become an issue due to the changes in the microstructure within the stir zone, perhaps creating a local galvanic couple. In this work, AA 5083-O aluminum plates were joined by FSW, and corrosion analyzes were undertaken. Therefore, corrosion behavior was investigated using an immersion test, open circuit potential (OCP), and zero-resistance ammeter (ZRA) measurements. The stirred material was found to be more resistant to pitting nucleation than the AA5083-O alloy base material on immersion test and OCP analyzes. Nevertheless, deeper pits were more significant in the stirred material. The ZRA test showed similar results for both regions, indicating this system’s low galvanic couple effect.","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70527225","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}
Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222595
T. B. Tavares, F. P. Finamor, Julio Cezar de Sousa Zorzi
The use of artificial intelligence techniques, with the increase of data generation capacity and the advancement of computational resources, has enabled the industries to develop and improve products without compromising laboratory and industrial resources. In this paper, a supervised machine learning (ML) based technique was used to predict the yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of dual phase steels with minimum tensile strengths of 590 and 780 MPa. The computational analysis was done from industrial data information containing the chemical composition and the thermomechanical processing parameters of the referred materials. The proposed ML model reached values of coefficient of determination above 0.94, with an accuracy of ±30 MPa for YS and UTS, and ±3% for EL. These results demonstrated the rationality and reliability of the tested method, allowing its application in future research works and in decision making that aim to optimize the steels industrial processing parameters.
{"title":"Mechanical properties prediction of dual phase steels using machine learning","authors":"T. B. Tavares, F. P. Finamor, Julio Cezar de Sousa Zorzi","doi":"10.4322/2176-1523.20222595","DOIUrl":"https://doi.org/10.4322/2176-1523.20222595","url":null,"abstract":"The use of artificial intelligence techniques, with the increase of data generation capacity and the advancement of computational resources, has enabled the industries to develop and improve products without compromising laboratory and industrial resources. In this paper, a supervised machine learning (ML) based technique was used to predict the yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of dual phase steels with minimum tensile strengths of 590 and 780 MPa. The computational analysis was done from industrial data information containing the chemical composition and the thermomechanical processing parameters of the referred materials. The proposed ML model reached values of coefficient of determination above 0.94, with an accuracy of ±30 MPa for YS and UTS, and ±3% for EL. These results demonstrated the rationality and reliability of the tested method, allowing its application in future research works and in decision making that aim to optimize the steels industrial processing parameters.","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70526221","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}
Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222547
F. Schild, V. M. Costa, L. V. Biehl, P. H. C. P. Cunha
Steels parts used in helicopters are critical in terms of mechanical performance and safety issues where failure can lead to catastrophic consequences. The objective of this study was to evaluate the influence of low temperatures on toughness, through impact testing, on 45NiCrMo16 steel alloy used in the manufacture of bolts used on a helicopter rotor. The aircraft that the studied bolt is used can operate in the Antarctic environment. The temperatures used in the Charpy tests were -40 ºC, -20 ºC, 0 ºC, and 25 ºC. Besides, microstructural analysis (optical and scanning microscopy) and microhardness were done to identify the steel phases/microconstituents and any surface treatment presence. The results showed the presence of a hardened layer, a decrease in impact toughness with decreasing temperature, and a transition from ductile to brittle fracture. The conclusions indicate behavior that can restrict or limit this steel grade application in extreme temperature conditions, that is the ductile-brittle transition region begins from a decrease in temperature starting from -20 ºC.
{"title":"Fragility analysis under low temperature of steel alloy used in helicopter bolt","authors":"F. Schild, V. M. Costa, L. V. Biehl, P. H. C. P. Cunha","doi":"10.4322/2176-1523.20222547","DOIUrl":"https://doi.org/10.4322/2176-1523.20222547","url":null,"abstract":"Steels parts used in helicopters are critical in terms of mechanical performance and safety issues where failure can lead to catastrophic consequences. The objective of this study was to evaluate the influence of low temperatures on toughness, through impact testing, on 45NiCrMo16 steel alloy used in the manufacture of bolts used on a helicopter rotor. The aircraft that the studied bolt is used can operate in the Antarctic environment. The temperatures used in the Charpy tests were -40 ºC, -20 ºC, 0 ºC, and 25 ºC. Besides, microstructural analysis (optical and scanning microscopy) and microhardness were done to identify the steel phases/microconstituents and any surface treatment presence. The results showed the presence of a hardened layer, a decrease in impact toughness with decreasing temperature, and a transition from ductile to brittle fracture. The conclusions indicate behavior that can restrict or limit this steel grade application in extreme temperature conditions, that is the ductile-brittle transition region begins from a decrease in temperature starting from -20 ºC.","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70526376","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}
Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222736
A. Alves, Felipe da Silva Siqueira, P. R. Rios
The advent of new materials may increase transformations that involve two or more product phases. This transformation involving two or more product phases may occur simultaneously or sequentially. It is well-known that heterogeneous nucleation has advantages over homogeneous nucleation. Several sites may become preferred because they favor heterogeneous nucleation. The interface of precipitates and the grain boundaries are one of the preferred locations for nucleation. We model simultaneous and sequential transformations nucleated at the preferred sites. This work employs both computer simulation and exact analytical solutions. Two product phases, 1 and 2, were considered. The product phase 1 nucleated at the matrix/particle interface and the product phase 2 nucleated at the grain boundaries. The analytical model showed an excellent agreement with simulation data. For each case, computer simulation obtained the microstructural evolution. We discussed the effect of nucleation at the preferred sites on the microstructure.
{"title":"Simultaneous and sequential transformations with nucleation at preferred sites","authors":"A. Alves, Felipe da Silva Siqueira, P. R. Rios","doi":"10.4322/2176-1523.20222736","DOIUrl":"https://doi.org/10.4322/2176-1523.20222736","url":null,"abstract":"The advent of new materials may increase transformations that involve two or more product phases. This transformation involving two or more product phases may occur simultaneously or sequentially. It is well-known that heterogeneous nucleation has advantages over homogeneous nucleation. Several sites may become preferred because they favor heterogeneous nucleation. The interface of precipitates and the grain boundaries are one of the preferred locations for nucleation. We model simultaneous and sequential transformations nucleated at the preferred sites. This work employs both computer simulation and exact analytical solutions. Two product phases, 1 and 2, were considered. The product phase 1 nucleated at the matrix/particle interface and the product phase 2 nucleated at the grain boundaries. The analytical model showed an excellent agreement with simulation data. For each case, computer simulation obtained the microstructural evolution. We discussed the effect of nucleation at the preferred sites on the microstructure.","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70526866","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}
Pub Date : 2022-01-01DOI: 10.4322/2176-1523.20222786
C. Santos, Elaine Carballo Siqueira Correa, J. Lima
{"title":"Avaliação prática da efetividade da nodularização in mold e sua aplicação na definição da microestrutura e das características dos ferros fundidos nodulares","authors":"C. Santos, Elaine Carballo Siqueira Correa, J. Lima","doi":"10.4322/2176-1523.20222786","DOIUrl":"https://doi.org/10.4322/2176-1523.20222786","url":null,"abstract":"","PeriodicalId":53327,"journal":{"name":"Tecnologia em Metalurgia Materiais e Mineracao","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70527148","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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