Lei Zhu, Y. Yang, Yuyang Li, Huanhuan Xuan, Hongtao Chen, Yanxiang Zhang, M. Yan
A low-carbon bainitic drilled steel exhibits high hardness after hot rolling, which is not conducive to machining. In order to soften this type of drilled steel less than 260 HB and accelerate the subsequent soft annealing, a pre-austenitizing was designed based on thermodynamic calculations of phase stability.Different initial microstructures were prepared with three austenitizing temperatures (680 oC, 850 oC, 1000 oC) and three cooling methods (water quenching, oil quenching, and air cooling). The effects of initial microstructure during annealing with different temperatures and times on microstructures and mechanical properties were studied. The softening equations as a function of λ-value was established for different initial microstructures, and the relationships between annealing temperature, annealing time, activation energy and hardness were explored. The predicted hardness were consistent with the measured values. The initial microstructures affect activation energy, i.e., the activation energy for diffusion with respect to the martensitic structure was less than that of the bainitic structure, and the corresponding softening rate with the martensitic initial structure was greater. In addition, the higher the carbide content in the bainitic structure, the greater the proportion of martensite in the martensite-retained austenite (M/A) structure, the more lath-shaped M/A and the less massive M/A, the smaller the activation energy tended to be.
{"title":"Effect of Initial Microstructure on Soft Annealing of a Low-Carbon Bainitic Steel","authors":"Lei Zhu, Y. Yang, Yuyang Li, Huanhuan Xuan, Hongtao Chen, Yanxiang Zhang, M. Yan","doi":"10.3390/IEC2M-09246","DOIUrl":"https://doi.org/10.3390/IEC2M-09246","url":null,"abstract":"A low-carbon bainitic drilled steel exhibits high hardness after hot rolling, which is not conducive to machining. In order to soften this type of drilled steel less than 260 HB and accelerate the subsequent soft annealing, a pre-austenitizing was designed based on thermodynamic calculations of phase stability.Different initial microstructures were prepared with three austenitizing temperatures (680 oC, 850 oC, 1000 oC) and three cooling methods (water quenching, oil quenching, and air cooling). The effects of initial microstructure during annealing with different temperatures and times on microstructures and mechanical properties were studied. The softening equations as a function of λ-value was established for different initial microstructures, and the relationships between annealing temperature, annealing time, activation energy and hardness were explored. The predicted hardness were consistent with the measured values. The initial microstructures affect activation energy, i.e., the activation energy for diffusion with respect to the martensitic structure was less than that of the bainitic structure, and the corresponding softening rate with the martensitic initial structure was greater. In addition, the higher the carbide content in the bainitic structure, the greater the proportion of martensite in the martensite-retained austenite (M/A) structure, the more lath-shaped M/A and the less massive M/A, the smaller the activation energy tended to be.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126035245","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}
Under quasi-static loading an irregular failure mode of high-strength thin-carbon steel cords were observed after low temperature thermal aging. Character and kinetics of damage in such wire ropes highly depend on the plastic elongation of the steel wires, which is significantly modified by the strain aging effect. In this paper, the static strain aging effect on heavily drawn high-carbon steel wires and their cords is experimentally studied in the 100–200 °C temperature range. Quantitative analysis of the affected strength and strain parameters is given. Kinetics of the aging process is discussed, and based on this, the macroscopic failure mechanism is fundamentally explained.
{"title":"Impact of strain aging kinetics on the failure of thin steel wire ropes","authors":"T. Mező, P. Barkóczy","doi":"10.3390/IEC2M-09243","DOIUrl":"https://doi.org/10.3390/IEC2M-09243","url":null,"abstract":"Under quasi-static loading an irregular failure mode of high-strength thin-carbon steel cords were observed after low temperature thermal aging. Character and kinetics of damage in such wire ropes highly depend on the plastic elongation of the steel wires, which is significantly modified by the strain aging effect. In this paper, the static strain aging effect on heavily drawn high-carbon steel wires and their cords is experimentally studied in the 100–200 °C temperature range. Quantitative analysis of the affected strength and strain parameters is given. Kinetics of the aging process is discussed, and based on this, the macroscopic failure mechanism is fundamentally explained.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132801377","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}
B. Sotillo, L. Alcaraz, F. López, F. J. Alguacil, O. Rodríguez, P. Fernández
: Niobium and tantalum-based oxides were recovered from mining tailings. These oxides were used as starting material for growing micro- and nanostructures by the evaporation method. The morphology and crystal structure of the final oxides were evaluated using X-ray diffraction (XRD), micro-Raman spectroscopy, and scanning electron microscopy (SEM). After the thermal treatment, microrods of both oxides were obtained, which presented exotic stoichiometries Nb 22 O 54 and K 6 Ta 10.8 O 30 , respectively.
:从尾矿中回收铌、钽基氧化物。这些氧化物被用作蒸发法制备微纳米结构的起始材料。利用x射线衍射(XRD)、微拉曼光谱(micro-Raman spectroscopy)和扫描电子显微镜(SEM)对最终氧化物的形貌和晶体结构进行了表征。热处理后得到了两种氧化物的微晶，其化学计量量分别为Nb 22 O 54和k6 Ta 10.8 O 30。
{"title":"Niobium oxide and tantalum oxide micro- and nanostructures grown using material recovered from mining tailings","authors":"B. Sotillo, L. Alcaraz, F. López, F. J. Alguacil, O. Rodríguez, P. Fernández","doi":"10.3390/IEC2M-09235","DOIUrl":"https://doi.org/10.3390/IEC2M-09235","url":null,"abstract":": Niobium and tantalum-based oxides were recovered from mining tailings. These oxides were used as starting material for growing micro- and nanostructures by the evaporation method. The morphology and crystal structure of the final oxides were evaluated using X-ray diffraction (XRD), micro-Raman spectroscopy, and scanning electron microscopy (SEM). After the thermal treatment, microrods of both oxides were obtained, which presented exotic stoichiometries Nb 22 O 54 and K 6 Ta 10.8 O 30 , respectively.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125012401","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. Sanchez-Caballero, M. A. Selles, R. Pla-Ferrando, J. Seguí, M. Peydro
: The rapid evolution of materials and manufacturing processes, driven by global competi-tion and new safety and environmental regulations has had an impact on automotive structures (Body In White; BIW) manufacturing. The need for lighter vehicles, with more equipment, that are safer and eco-friendly at the same time, relates to the entire life cycle of the car. Car and steelmakers agree that weight reduction is possible, and the solution involves the use of new advanced high-strength steels. Thinner and stronger materials lead to higher demands on stamping, the most used manufacturing in BIW parts. The use of advanced high-strength steels raises new challenges, especially concerning the lubrication between the die and the sheet. To study the lubrication conditions of the stamping process, a sheet metal forming a simulator was developed. The simulator consists of two cylinders that pull the strip of steel and a pin in between. The angle between the cylinders can be adjusted from 0 to 90 degrees, which allows analysis of the effect of the stamping angle. The pull force and velocity can be set and measured, and the peripheric pin velocity, the strain, and the strain velocity can be measured as well. In this work, the tribological properties of Dual-Phase 600 stainless steel using different processing conditions have been analyzed. To this end, a factorial experiments design with twelve parameters that compare the behavior of different angles and diameters was run. The results showed that the friction coefficient increases by increasing the bending angle and decreases with pin diameter.
{"title":"Research on the friction properties of DP600 stainless steel as a function of bending angle and pin diameter","authors":"S. Sanchez-Caballero, M. A. Selles, R. Pla-Ferrando, J. Seguí, M. Peydro","doi":"10.3390/IEC2M-09248","DOIUrl":"https://doi.org/10.3390/IEC2M-09248","url":null,"abstract":": The rapid evolution of materials and manufacturing processes, driven by global competi-tion and new safety and environmental regulations has had an impact on automotive structures (Body In White; BIW) manufacturing. The need for lighter vehicles, with more equipment, that are safer and eco-friendly at the same time, relates to the entire life cycle of the car. Car and steelmakers agree that weight reduction is possible, and the solution involves the use of new advanced high-strength steels. Thinner and stronger materials lead to higher demands on stamping, the most used manufacturing in BIW parts. The use of advanced high-strength steels raises new challenges, especially concerning the lubrication between the die and the sheet. To study the lubrication conditions of the stamping process, a sheet metal forming a simulator was developed. The simulator consists of two cylinders that pull the strip of steel and a pin in between. The angle between the cylinders can be adjusted from 0 to 90 degrees, which allows analysis of the effect of the stamping angle. The pull force and velocity can be set and measured, and the peripheric pin velocity, the strain, and the strain velocity can be measured as well. In this work, the tribological properties of Dual-Phase 600 stainless steel using different processing conditions have been analyzed. To this end, a factorial experiments design with twelve parameters that compare the behavior of different angles and diameters was run. The results showed that the friction coefficient increases by increasing the bending angle and decreases with pin diameter.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124618766","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. A. Selles, S. Sanchez-Caballero, Jaume Gomez-Caturla, O. Gonzalez, Miguel Angel Peydró-Rasero
Digital Image analysis is used, among other things, to see how an object's surface changes over time. This technology can be applied to metal forming. A complete literature review of the recent advances in the application of such image analysis to metal forming processes is presented. We analyze how researchers apply the technique to different tests (tensile, bending, or fatigue tests), observing the advantages it presents compared to conventional methods, as well as the advances that have been made regarding the methodology used throughout the last years, including an analysis of the different existing patterns and their application procedures. We found that the image analysis has great applicability and that, in addition, the data obtained through it have high reliability when compared with numerical results. In the paper, the advantages of using Digital Image analysis applied to metals characterization are reviewed, and some examples of using this technique are also presented.
{"title":"Recent advances in Digital Image analysis applied to metal forming","authors":"M. A. Selles, S. Sanchez-Caballero, Jaume Gomez-Caturla, O. Gonzalez, Miguel Angel Peydró-Rasero","doi":"10.3390/IEC2M-09249","DOIUrl":"https://doi.org/10.3390/IEC2M-09249","url":null,"abstract":"Digital Image analysis is used, among other things, to see how an object's surface changes over time. This technology can be applied to metal forming. A complete literature review of the recent advances in the application of such image analysis to metal forming processes is presented. We analyze how researchers apply the technique to different tests (tensile, bending, or fatigue tests), observing the advantages it presents compared to conventional methods, as well as the advances that have been made regarding the methodology used throughout the last years, including an analysis of the different existing patterns and their application procedures. We found that the image analysis has great applicability and that, in addition, the data obtained through it have high reliability when compared with numerical results. In the paper, the advantages of using Digital Image analysis applied to metals characterization are reviewed, and some examples of using this technique are also presented.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127590639","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}
Hot stamping technology has shown a significant scientific yield in the last decade. The research activity in that field has spread across several disciplines such as materials science, mechanics, process engineering, instrumentation, physics, or part-tool design engineering. Some recent publications have gathered this richness in the format of scientific reviews. This work is aimed to draw a picture of this scientific production in bibliometric terms, which are complementary to the existing reviews. The literature is, in this case, approached from different angles: geographical, collaborative, disseminative and keyword based. The first one leads to mapping the share of each region worldwide in the advance of the hot stamping technology in terms of scientific production volume. The second angle allows identifying the most productive networks that have been stablished between institutions and the most influent agents in the field. The third one ranks the most influent journals and events based on citation rates, which indicates where to publish in order to get the highest impact. Finally, the fourth approach targets to infer research trends from assessing the keywords employed in the published scientific literature. Altogether, the results show a scenario with Asia as the major player both in volume and networking success, CHS2 as the most relevant event and exploring alternatives to the conventional AlSi coated 22MnB5 hot stamping as a subject rising of interest.
{"title":"Hot stamping research scenarios from the last decade","authors":"Luis Miguel Arias, G. Artola, Igone Porto","doi":"10.3390/IEC2M-09245","DOIUrl":"https://doi.org/10.3390/IEC2M-09245","url":null,"abstract":"Hot stamping technology has shown a significant scientific yield in the last decade. The research activity in that field has spread across several disciplines such as materials science, mechanics, process engineering, instrumentation, physics, or part-tool design engineering. Some recent publications have gathered this richness in the format of scientific reviews. This work is aimed to draw a picture of this scientific production in bibliometric terms, which are complementary to the existing reviews. The literature is, in this case, approached from different angles: geographical, collaborative, disseminative and keyword based. The first one leads to mapping the share of each region worldwide in the advance of the hot stamping technology in terms of scientific production volume. The second angle allows identifying the most productive networks that have been stablished between institutions and the most influent agents in the field. The third one ranks the most influent journals and events based on citation rates, which indicates where to publish in order to get the highest impact. Finally, the fourth approach targets to infer research trends from assessing the keywords employed in the published scientific literature. Altogether, the results show a scenario with Asia as the major player both in volume and networking success, CHS2 as the most relevant event and exploring alternatives to the conventional AlSi coated 22MnB5 hot stamping as a subject rising of interest.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133459244","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}
G. Haidemenopoulos, M. Sotiriou, John S. Aristeidakis, Maria-Ioanna T. Tzini, I. Papadioti, N. Aravas
Additive manufacturing of an AISI 316L austenitic stainless steel was studied via an integrated thermomechanical and microstructural modelling approach. A finite element technique was employed to evaluate the temperature evolution due to successive material deposition. Heat transfer simulations provided the temperature field history, required to determine the microstructural evolution. Thermodynamic and kinetic simulations were employed to calculate temporal and spatial distribution of phases and alloying elements upon solidification and subsequent thermal cycling. The ensuing microstructural properties could be provided as an input for a mechanical finite element analysis to calculate, based on local mechanical properties, the residual stresses and distortions.
{"title":"Microstructural and thermomechanical simulation of the additive manufacturing process in 316L austenitic stainless steel","authors":"G. Haidemenopoulos, M. Sotiriou, John S. Aristeidakis, Maria-Ioanna T. Tzini, I. Papadioti, N. Aravas","doi":"10.3390/IEC2M-09237","DOIUrl":"https://doi.org/10.3390/IEC2M-09237","url":null,"abstract":"Additive manufacturing of an AISI 316L austenitic stainless steel was studied via an integrated thermomechanical and microstructural modelling approach. A finite element technique was employed to evaluate the temperature evolution due to successive material deposition. Heat transfer simulations provided the temperature field history, required to determine the microstructural evolution. Thermodynamic and kinetic simulations were employed to calculate temporal and spatial distribution of phases and alloying elements upon solidification and subsequent thermal cycling. The ensuing microstructural properties could be provided as an input for a mechanical finite element analysis to calculate, based on local mechanical properties, the residual stresses and distortions.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125096603","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}
Song Zhu, Youichi Nakahara, H. Aono, R. Ejima, Motomichi Yamamoto
The aim of this research was to develop a high-efficiency and high-material-utilization additive manufacturing technology using the hot-wire laser method. In this study, the optimization of process conditions using a combination of a high-power diode laser with a relatively large laser spot hot-wire system was investigated. The effects of welding parameters such as the laser power, process speed, and wire feeding rate (wire feeding speed/process speed) on the bead appearance evaluation and the cross-sectional characteristics ( e.g. effective width, effective height, maximum height, and near net shape rate) were studied in detail. The process phenomena of the three-layer and multi-layer deposition were investigated by in-situ observation via a high-speed camera. Energy density input and wire feeding rate were found to be dominant parameters influencing both the stability of phenomena and bead appearance. With the increase of process speed, the effective width decreases, the effective height, maximum height, and the near net shape rate increases. Additionally, all measured values of the wire feeding rate of 30 improve compared with the values of the wire feeding rate of 20. The near net shape rate increased and the effective width over 10mm of three-layer deposition for the laser spot width of 11 mm was obtained with suitable process parameters. The defect-free 15-layer wall modeling of more than 50 mm in height, 8 mm in width, and 250 mm in length was obtained with high efficiency using the optimum conditions by the hot-wire laser method.
{"title":"Derivation of appropriate conditions for Additive Manufacturing technology using hot-wire laser method","authors":"Song Zhu, Youichi Nakahara, H. Aono, R. Ejima, Motomichi Yamamoto","doi":"10.3390/IEC2M-09244","DOIUrl":"https://doi.org/10.3390/IEC2M-09244","url":null,"abstract":"The aim of this research was to develop a high-efficiency and high-material-utilization additive manufacturing technology using the hot-wire laser method. In this study, the optimization of process conditions using a combination of a high-power diode laser with a relatively large laser spot hot-wire system was investigated. The effects of welding parameters such as the laser power, process speed, and wire feeding rate (wire feeding speed/process speed) on the bead appearance evaluation and the cross-sectional characteristics ( e.g. effective width, effective height, maximum height, and near net shape rate) were studied in detail. The process phenomena of the three-layer and multi-layer deposition were investigated by in-situ observation via a high-speed camera. Energy density input and wire feeding rate were found to be dominant parameters influencing both the stability of phenomena and bead appearance. With the increase of process speed, the effective width decreases, the effective height, maximum height, and the near net shape rate increases. Additionally, all measured values of the wire feeding rate of 30 improve compared with the values of the wire feeding rate of 20. The near net shape rate increased and the effective width over 10mm of three-layer deposition for the laser spot width of 11 mm was obtained with suitable process parameters. The defect-free 15-layer wall modeling of more than 50 mm in height, 8 mm in width, and 250 mm in length was obtained with high efficiency using the optimum conditions by the hot-wire laser method.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115431615","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}
D. Zinoveev, A. Petelin, P. Grudinsky, A. Zakunov, V. Dyubanov
Red mud is a hazardous waste of alumina production. Currently, the total accumulated amount of red mud is over 4 billion tons. The promising method of red mud processing is carbothermic reduction of iron at 1000–1400 °C into metallic form followed by magnetic separation. In this study, the mechanism of carbothermic solid-phase reduction of red mud was investigated. Based on the experimental data, the two-step mechanism of the first rapid stage of the process was proposed, which leads to almost full iron reduction. The estimated value of activation energy has indicated that solid-phase diffusion is a rate-controlling step for this stage. However, almost full reduction is necessary, but insufficient factor for successful magnetic separation. The second crucial factor of the process is enlargement of iron grain size, which leads to gangue-grain release during grinding and increases efficiency of the magnetic separation. The prediction model of iron grain growth process during the carbothermic reduction process was suggested. The calculation of average size of iron grains formed during reduction process that performed according to the assumption of diffusion-controlled process showed their correlation with experimental data. Various methods were proposed to promote the process of iron grain growth during carbothermic reduction of red mud.
{"title":"Extraction of iron from Russian red mud by a carbothermic reduction and magnetic separation process","authors":"D. Zinoveev, A. Petelin, P. Grudinsky, A. Zakunov, V. Dyubanov","doi":"10.3390/IEC2M-09247","DOIUrl":"https://doi.org/10.3390/IEC2M-09247","url":null,"abstract":"Red mud is a hazardous waste of alumina production. Currently, the total accumulated amount of red mud is over 4 billion tons. The promising method of red mud processing is carbothermic reduction of iron at 1000–1400 °C into metallic form followed by magnetic separation. In this study, the mechanism of carbothermic solid-phase reduction of red mud was investigated. Based on the experimental data, the two-step mechanism of the first rapid stage of the process was proposed, which leads to almost full iron reduction. The estimated value of activation energy has indicated that solid-phase diffusion is a rate-controlling step for this stage. However, almost full reduction is necessary, but insufficient factor for successful magnetic separation. The second crucial factor of the process is enlargement of iron grain size, which leads to gangue-grain release during grinding and increases efficiency of the magnetic separation. The prediction model of iron grain growth process during the carbothermic reduction process was suggested. The calculation of average size of iron grains formed during reduction process that performed according to the assumption of diffusion-controlled process showed their correlation with experimental data. Various methods were proposed to promote the process of iron grain growth during carbothermic reduction of red mud.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127590852","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. Barella, A. Gruttadauria, Riccardo Gerosa, Giacomo Mainetti, Teodoro Mainetti
: During the last fifty years, the metal forming of aluminum alloys advanced significantly, leading to a more competitive market on which production rate and overall quality are kept as high as possible. Within the aluminum industries, extrusion plays an important role, since many industrial products with structural or even aesthetic functions are realized with this technology. Especially in the automotive industry, the use of aluminum alloys is growing very fast, since it permits a considerable weight loss and thus a reduction of the emission. Nevertheless, the stringent quality standards required don’t allow the use of extruded aluminum alloys produced for common build-ing applications. An important parameter that can be used as an index of the quality of the extruded product is the emergent temperature: if the temperature at the exit of the press is kept constant within a certain limit, products with homogeneous properties and high-quality surface are obtained and the so called “isothermal extrusion” is achieved. As extrusion industries are spread all over the world with different levels of automation and control, a universal but simple on-line tool for deter-mining the best process condition to achieve isothermal extrusion is of particular interest. The aim of this work is to implement this model, which allows evaluation of the thermal gradient which has to be imposed on the billet. Several experiments have been carried out on an industrial extrusion press, and the outer temperature was recorded and compared with the simulated one to demon-strate the model consistency.
{"title":"PREDICTIVE TOOLS FOR IN-LINE ISOTHERMAL EXTRUSION OF 6XXX ALUMINUM ALLOYS","authors":"S. Barella, A. Gruttadauria, Riccardo Gerosa, Giacomo Mainetti, Teodoro Mainetti","doi":"10.3390/IEC2M-09239","DOIUrl":"https://doi.org/10.3390/IEC2M-09239","url":null,"abstract":": During the last fifty years, the metal forming of aluminum alloys advanced significantly, leading to a more competitive market on which production rate and overall quality are kept as high as possible. Within the aluminum industries, extrusion plays an important role, since many industrial products with structural or even aesthetic functions are realized with this technology. Especially in the automotive industry, the use of aluminum alloys is growing very fast, since it permits a considerable weight loss and thus a reduction of the emission. Nevertheless, the stringent quality standards required don’t allow the use of extruded aluminum alloys produced for common build-ing applications. An important parameter that can be used as an index of the quality of the extruded product is the emergent temperature: if the temperature at the exit of the press is kept constant within a certain limit, products with homogeneous properties and high-quality surface are obtained and the so called “isothermal extrusion” is achieved. As extrusion industries are spread all over the world with different levels of automation and control, a universal but simple on-line tool for deter-mining the best process condition to achieve isothermal extrusion is of particular interest. The aim of this work is to implement this model, which allows evaluation of the thermal gradient which has to be imposed on the billet. Several experiments have been carried out on an industrial extrusion press, and the outer temperature was recorded and compared with the simulated one to demon-strate the model consistency.","PeriodicalId":429720,"journal":{"name":"Proceedings of The 1st International Electronic Conference on Metallurgy and Metals","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134569199","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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