Pub Date : 2020-01-01DOI: 10.37904/metal.2020.3510
I. Danev, D. Gospodinov, R. Radev, M. Ilieva
Currently, heat treatment is the most common and effective method for changing the properties of metals and their alloys. Ferrous alloys most often are heat treated and the most commonly used process of heat treatment is the quenching. At quenching the final structure and material’s properties are formed during the fast cooling process. Therefore, the correct choice of cooling conditions is critical for quality of quenched parts. The simulation of quenching is one of the modern approaches for researching the cooling processes. In order to obtain reliable results, the correct input data for simulation are crucial. It is commonly accepted that the heat transfer coefficient (HTC) plays most significant influence on the simulation results. Meanwhile in the specialized literature there are quite different values of HTC even at equal cooling conditions and a few data regarding its influence on the simulation results. The aim of this paper is to determine to what extent the results obtained after simulation of quenching processes are influenced by HTC. Samples of different dimensions and ratios between length and diameter (L/D), made of medium carbon steel (C45 EN 10083), were studied. Results for the influence of HTC together with geometry of the quenched parts, especially samples with different ratio length/diameter (L/D), are presented in the article.
目前，热处理是改变金属及其合金性能的最常见和最有效的方法。铁合金最常进行热处理，最常用的热处理工艺是淬火。淬火时，材料的最终组织和性能是在快速冷却过程中形成的。因此，正确选择冷却条件对淬火件的质量至关重要。淬火模拟是研究冷却过程的现代方法之一。为了获得可靠的仿真结果，正确的仿真输入数据至关重要。一般认为传热系数(HTC)对模拟结果的影响最为显著。同时，在专业文献中，即使在相同的冷却条件下，HTC的数值也相差很大，关于其对模拟结果影响的数据也很少。本文的目的是确定淬火过程模拟后得到的结果在多大程度上受到HTC的影响。对中碳钢(C45 EN 10083)不同尺寸和长径比(L/D)试样进行了研究。文中给出了HTC和淬火件几何形状的影响，特别是不同长径比(L/D)试样的影响。
{"title":"INFLUENCE OF HEAT TRANSFER COEFFICIENT ON QUENCHING PROCESSES SIMULATION","authors":"I. Danev, D. Gospodinov, R. Radev, M. Ilieva","doi":"10.37904/metal.2020.3510","DOIUrl":"https://doi.org/10.37904/metal.2020.3510","url":null,"abstract":"Currently, heat treatment is the most common and effective method for changing the properties of metals and their alloys. Ferrous alloys most often are heat treated and the most commonly used process of heat treatment is the quenching. At quenching the final structure and material’s properties are formed during the fast cooling process. Therefore, the correct choice of cooling conditions is critical for quality of quenched parts. The simulation of quenching is one of the modern approaches for researching the cooling processes. In order to obtain reliable results, the correct input data for simulation are crucial. It is commonly accepted that the heat transfer coefficient (HTC) plays most significant influence on the simulation results. Meanwhile in the specialized literature there are quite different values of HTC even at equal cooling conditions and a few data regarding its influence on the simulation results. The aim of this paper is to determine to what extent the results obtained after simulation of quenching processes are influenced by HTC. Samples of different dimensions and ratios between length and diameter (L/D), made of medium carbon steel (C45 EN 10083), were studied. Results for the influence of HTC together with geometry of the quenched parts, especially samples with different ratio length/diameter (L/D), are presented in the article.","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85586901","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 : 2020-01-01DOI: 10.37904/metal.2020.3513
O. Ambrož, Š. Mikmeková, Veronika Hegrová, T. Aoyama
Modern scanning electron microscopy (SEM) allows observations of specimens with high surface sensitivity. The surface sensitivity is significantly affected by the accelerating voltages. With the development of the scanning electron microscopy, the requirements for the surface quality of samples increase. Metallographic methods originally intended for light microscopy become insufficient. The problem occurs especially with multiphase materials having a fine-grained structure. The investigated TRIP steel consists of a ferritic-bainitic matrix, retained austenite and martensite phases. The sizes of the smallest phases are nanometer units. The volume of residual austenite was determined by X-ray diffraction. The basic preparation of all tested samples involved conventional metallographic grinding and very fine mechanical polishing. One sample was analysed in this state. Other samples were subsequently chemically polished, electropolished and chemical-mechanically polished. The specimens were observed in the SEM using a SE and a BSE detector at low energies immediately after the preparation. An EBSD was performed in the same areas to characterize the retained austenite. Topographical imaging by special AFM, integrated into the SEM, demonstrated that the mechanical polishing results in surface deformation and residual austenite is transformed. All other methods have their specifics and for modern sensitive SEM instruments it is necessary to optimize individual procedures.
{"title":"TRIP STEEL SPECIMEN PREPARATION FOR ADVANCED SEM AND EBSD","authors":"O. Ambrož, Š. Mikmeková, Veronika Hegrová, T. Aoyama","doi":"10.37904/metal.2020.3513","DOIUrl":"https://doi.org/10.37904/metal.2020.3513","url":null,"abstract":"Modern scanning electron microscopy (SEM) allows observations of specimens with high surface sensitivity. The surface sensitivity is significantly affected by the accelerating voltages. With the development of the scanning electron microscopy, the requirements for the surface quality of samples increase. Metallographic methods originally intended for light microscopy become insufficient. The problem occurs especially with multiphase materials having a fine-grained structure. The investigated TRIP steel consists of a ferritic-bainitic matrix, retained austenite and martensite phases. The sizes of the smallest phases are nanometer units. The volume of residual austenite was determined by X-ray diffraction. The basic preparation of all tested samples involved conventional metallographic grinding and very fine mechanical polishing. One sample was analysed in this state. Other samples were subsequently chemically polished, electropolished and chemical-mechanically polished. The specimens were observed in the SEM using a SE and a BSE detector at low energies immediately after the preparation. An EBSD was performed in the same areas to characterize the retained austenite. Topographical imaging by special AFM, integrated into the SEM, demonstrated that the mechanical polishing results in surface deformation and residual austenite is transformed. All other methods have their specifics and for modern sensitive SEM instruments it is necessary to optimize individual procedures.","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88565133","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 : 2020-01-01DOI: 10.37904/metal.2020.3514
I. Belyaev, D. Serov, A. Kireev, A. Kutepov, A. Lyukhter, A. Zhokin, V. Rykov, N. Kolchugina
The possibility of laser cutting of rare-earth NdFeB permanent magnets is studied. An industrial Navigator KS-5VDM1-3 laser complex (VNITER, Russia) is used. Blanks of sintered permanent magnets intended for cutting were 10, 4.5, 3, and 2 mm thick. The cutting was performed in air. The used cutting conditions ensure the cutting of a blank for one pass. The cutting rate was varied in wide range. The magnetic properties of studied blanks were determined via measuring the magnetization reversal curves recorded before and after cutting. Changes in the alloy structure during laser cutting were estimated by X-ray diffraction analysis. The decrease in the magnetic properties during laser cutting was found to depend on the blank thickness. The thinner the magnet blank, the lower the decrease in its magnetic properties. The causes for the decrease in the magnetic properties of NdFeB permanent magnet blanks during laser cutting are local changing the phase composition of alloy and decrease in the degree of texture of blanks. The losses of magnetic properties can be minimized by optimization of laser cutting conditions.
{"title":"LASER CUTTING OF RARE-EARTH NdFeB PERMANENT MAGNETS","authors":"I. Belyaev, D. Serov, A. Kireev, A. Kutepov, A. Lyukhter, A. Zhokin, V. Rykov, N. Kolchugina","doi":"10.37904/metal.2020.3514","DOIUrl":"https://doi.org/10.37904/metal.2020.3514","url":null,"abstract":"The possibility of laser cutting of rare-earth NdFeB permanent magnets is studied. An industrial Navigator KS-5VDM1-3 laser complex (VNITER, Russia) is used. Blanks of sintered permanent magnets intended for cutting were 10, 4.5, 3, and 2 mm thick. The cutting was performed in air. The used cutting conditions ensure the cutting of a blank for one pass. The cutting rate was varied in wide range. The magnetic properties of studied blanks were determined via measuring the magnetization reversal curves recorded before and after cutting. Changes in the alloy structure during laser cutting were estimated by X-ray diffraction analysis. The decrease in the magnetic properties during laser cutting was found to depend on the blank thickness. The thinner the magnet blank, the lower the decrease in its magnetic properties. The causes for the decrease in the magnetic properties of NdFeB permanent magnet blanks during laser cutting are local changing the phase composition of alloy and decrease in the degree of texture of blanks. The losses of magnetic properties can be minimized by optimization of laser cutting conditions.","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88846096","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 : 2020-01-01DOI: 10.37904/metal.2020.3533
Oleksandr Kapustynskyi, N. Višniakov
The main objective of the research was to determine the influence of local laser treatment on the process of elastoplastic deflection of the sheets under bending force. FEA modelling results show, that the location of the treated area and the number of laser tracks on a thin-walled sheet surface had a large influence on the stress distribution and sheet deflections during bending. The FEA analysis of equivalent Von-Mises stresses, normal stresses, deflection of steel sheets and applied bending forces confirms that the steel samples with the laser-treated area have greater resistance against bending and reduced deflection under the same bending forces. FEA investigation shows that a greater strengthening effect on thin-walled steel sheets could be achieved through the application of double-sided laser treatment of the sheet surface in comparison with untreated or one-side treated steel sheets.
{"title":"FEA analysis of bending stress and deflection in thin steel sheet with reinforcing ribs created by laser treatment","authors":"Oleksandr Kapustynskyi, N. Višniakov","doi":"10.37904/metal.2020.3533","DOIUrl":"https://doi.org/10.37904/metal.2020.3533","url":null,"abstract":"The main objective of the research was to determine the influence of local laser treatment on the process of elastoplastic deflection of the sheets under bending force. FEA modelling results show, that the location of the treated area and the number of laser tracks on a thin-walled sheet surface had a large influence on the stress distribution and sheet deflections during bending. The FEA analysis of equivalent Von-Mises stresses, normal stresses, deflection of steel sheets and applied bending forces confirms that the steel samples with the laser-treated area have greater resistance against bending and reduced deflection under the same bending forces. FEA investigation shows that a greater strengthening effect on thin-walled steel sheets could be achieved through the application of double-sided laser treatment of the sheet surface in comparison with untreated or one-side treated steel sheets.","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87223278","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 : 2020-01-01DOI: 10.37904/metal.2020.3457
L. Polcar, R. Pyszko
Production of new steel grades and growing demands on productivity require an increasing understanding of heat transfer during the continuous casting process. This work is focused on a mould which has a great influence on the casting process and the final quality of billets. Casting speed has to be adapted to the steel parameters and the format of the product. The temperature field of the mould changes with the casting speed. From the temperature field, the contact of the solid shell with the mould insert and the intensity and symmetry of heat removal can be deduced. Temperature measurements were conducted in the mould walls on site. It was found that increasing the casting speed reduced the temperature gradient in the longitudinal direction and caused a decrease in the unevenness of the temperature field in the transverse direction, which was expressed by the so-called thermal axis. A percentage increase in mould temperatures that followed the increase in casting speed, exhibited close to a linear dependency on the distance from the mould top. Based on the presented data, the increase in casting speed caused a more uniform temperature field in the mould insert, which is related to a more uniform heat removal from the billet.
{"title":"impact of casting speed on mould wall TEMPERATURE FIELD","authors":"L. Polcar, R. Pyszko","doi":"10.37904/metal.2020.3457","DOIUrl":"https://doi.org/10.37904/metal.2020.3457","url":null,"abstract":"Production of new steel grades and growing demands on productivity require an increasing understanding of heat transfer during the continuous casting process. This work is focused on a mould which has a great influence on the casting process and the final quality of billets. Casting speed has to be adapted to the steel parameters and the format of the product. The temperature field of the mould changes with the casting speed. From the temperature field, the contact of the solid shell with the mould insert and the intensity and symmetry of heat removal can be deduced. Temperature measurements were conducted in the mould walls on site. It was found that increasing the casting speed reduced the temperature gradient in the longitudinal direction and caused a decrease in the unevenness of the temperature field in the transverse direction, which was expressed by the so-called thermal axis. A percentage increase in mould temperatures that followed the increase in casting speed, exhibited close to a linear dependency on the distance from the mould top. Based on the presented data, the increase in casting speed caused a more uniform temperature field in the mould insert, which is related to a more uniform heat removal from the billet.","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90476958","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 : 2020-01-01DOI: 10.37904/metal.2020.3439
S. Matkarimov
In article questions of development, low-waste technologies of processing of steel-smelting slag are considered, gland allowing by extraction and its connections from steel-smelting slag to receive additional raw materials for production became, and the remains to use in building industry. Complex processing of steelsmelting slags as the main way of engineering-ecological development of society was offered in the mid-sixties the past century, generally by scientists from the CIS countries. Based on their application, it was supposed not only it is most useful to use the consumed raw material resources, but also to try to process formed entirely waste. Thus present at a firm oxidizer iron assimilates with metal and promotes degree increase complex raw materials use. In this case, as firm oxidizers can be used, oxides the connections of iron taken from utilized slags of joint-stock company "Uzbeksteel."
{"title":"HEAT TREATMENT PROCESSES OF STEEL-SMELTING SLAGS IN THE RECOVERY ENVIRONMENT","authors":"S. Matkarimov","doi":"10.37904/metal.2020.3439","DOIUrl":"https://doi.org/10.37904/metal.2020.3439","url":null,"abstract":"In article questions of development, low-waste technologies of processing of steel-smelting slag are considered, gland allowing by extraction and its connections from steel-smelting slag to receive additional raw materials for production became, and the remains to use in building industry. Complex processing of steelsmelting slags as the main way of engineering-ecological development of society was offered in the mid-sixties the past century, generally by scientists from the CIS countries. Based on their application, it was supposed not only it is most useful to use the consumed raw material resources, but also to try to process formed entirely waste. Thus present at a firm oxidizer iron assimilates with metal and promotes degree increase complex raw materials use. In this case, as firm oxidizers can be used, oxides the connections of iron taken from utilized slags of joint-stock company \"Uzbeksteel.\"","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84805805","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 : 2020-01-01DOI: 10.37904/metal.2020.3612
Irena Lysoňková, J. Svobodová, I. Hren
Aluminum alloy EN AW-2024 (AlCu4Mg1 - dural) – Al-Cu-Mg group is one of the most used alloys from this group, which achieves considerable strength after heat treatment. It is an alloy with higher and high strength, but low corrosion resistance. The mechanical properties of Al-Cu alloys depend on whether Cu is present in the aluminum solid solution α in the form of a spheroid, possibly as dispersed particles or if it is forming a network at grain boundaries. The paper is focused on the evaluation (microstructure, grain size, phase fraction, hardness) of this particular alloy using AlTi5B1 inoculant in various concentrations to refine the alloy grain. The heat treatment of the alloy was also performed in the experiment to increase the mechanical properties. Inoculation of aluminum alloys is performed to improve the mechanical and technological properties of the material. In the case of inoculation, this improvement is mainly due to an increase in chemical and structural homogeneity and a decrease in the tendency to segregate individual elements. Optical microscopy and image phase analysis was used to observe the microstructure, which evaluated the microstructure and its changes depending on the content of the inoculant and also the effect of heat treatment in the combination of different amount of inoculant. It is generally known that AlTi5B1 acts in certain amounts to refining the alloy grain. Our work is based on the knowledge of the behaviour of different concentrations of inoculant in this particular AlCu4Mg1 alloy and responds to the requirement from practice. We achieved the best results with a concentration 3 wt% of AlTi5B1. For the other concentrations, the results were almost comparable and not much worse than for the concentration with the best results. It doesn't make sense to add more than 3 wt% of inoculant in this case.
{"title":"EFFECT OF AlTi3B1 INOCULANT ON THE MICROSTRUCTURE AND HARDNESS OF THE AlCu4Mg1 ALLOY","authors":"Irena Lysoňková, J. Svobodová, I. Hren","doi":"10.37904/metal.2020.3612","DOIUrl":"https://doi.org/10.37904/metal.2020.3612","url":null,"abstract":"Aluminum alloy EN AW-2024 (AlCu4Mg1 - dural) – Al-Cu-Mg group is one of the most used alloys from this group, which achieves considerable strength after heat treatment. It is an alloy with higher and high strength, but low corrosion resistance. The mechanical properties of Al-Cu alloys depend on whether Cu is present in the aluminum solid solution α in the form of a spheroid, possibly as dispersed particles or if it is forming a network at grain boundaries. The paper is focused on the evaluation (microstructure, grain size, phase fraction, hardness) of this particular alloy using AlTi5B1 inoculant in various concentrations to refine the alloy grain. The heat treatment of the alloy was also performed in the experiment to increase the mechanical properties. Inoculation of aluminum alloys is performed to improve the mechanical and technological properties of the material. In the case of inoculation, this improvement is mainly due to an increase in chemical and structural homogeneity and a decrease in the tendency to segregate individual elements. Optical microscopy and image phase analysis was used to observe the microstructure, which evaluated the microstructure and its changes depending on the content of the inoculant and also the effect of heat treatment in the combination of different amount of inoculant. It is generally known that AlTi5B1 acts in certain amounts to refining the alloy grain. Our work is based on the knowledge of the behaviour of different concentrations of inoculant in this particular AlCu4Mg1 alloy and responds to the requirement from practice. We achieved the best results with a concentration 3 wt% of AlTi5B1. For the other concentrations, the results were almost comparable and not much worse than for the concentration with the best results. It doesn't make sense to add more than 3 wt% of inoculant in this case.","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84899646","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 : 2020-01-01DOI: 10.37904/metal.2020.3455
M. Topinková, J. Vlček, M. Klárová, H. Ovčačíková, P. Maierová, V. Blahůšková
Granulated blast furnace slag exhibits latent hydraulic properties and its binding properties can be evoked by the addition of the alkali activator. Subsequent hydration processes during the setting and hardening processes let to origination of the solid products with the mechanical properties comparable or even better than the product obtained with ordinary Portland cement. The dominant product of the hydration processes is so called C-S-H phase. C-S-H phases are non-crystalline products of hydration with variable composition based on CaO, SiO2 and H2O. C-S-H phases are responsible for good mechanical properties of the hydrated products. The paper deals with the effect of the addition of the synthetically produced C-S-H phases on the hydration processes of granulated blast furnace slag. C-S-H phases were synthesized using the sol-gel method and were added to the granulated slag at the beginning of its hydration with the role of the nuclei of the phases responsible for strength of the final hydrated products. The mechanical properties as well as the development of the porous structure of hydrated products were used for the evaluation of the effect of the nuclei addition on the hydration process. It was proved that the addition of the synthetically prepared C-S-H nuclei has a positive effect on the development of the mechanical properties of alkali activated blast furnace slag, especially during the initial period of hardening.
{"title":"Modification of the hydration processes of alkali activated blast furnace slag","authors":"M. Topinková, J. Vlček, M. Klárová, H. Ovčačíková, P. Maierová, V. Blahůšková","doi":"10.37904/metal.2020.3455","DOIUrl":"https://doi.org/10.37904/metal.2020.3455","url":null,"abstract":"Granulated blast furnace slag exhibits latent hydraulic properties and its binding properties can be evoked by the addition of the alkali activator. Subsequent hydration processes during the setting and hardening processes let to origination of the solid products with the mechanical properties comparable or even better than the product obtained with ordinary Portland cement. The dominant product of the hydration processes is so called C-S-H phase. C-S-H phases are non-crystalline products of hydration with variable composition based on CaO, SiO2 and H2O. C-S-H phases are responsible for good mechanical properties of the hydrated products. The paper deals with the effect of the addition of the synthetically produced C-S-H phases on the hydration processes of granulated blast furnace slag. C-S-H phases were synthesized using the sol-gel method and were added to the granulated slag at the beginning of its hydration with the role of the nuclei of the phases responsible for strength of the final hydrated products. The mechanical properties as well as the development of the porous structure of hydrated products were used for the evaluation of the effect of the nuclei addition on the hydration process. It was proved that the addition of the synthetically prepared C-S-H nuclei has a positive effect on the development of the mechanical properties of alkali activated blast furnace slag, especially during the initial period of hardening.","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80873721","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 : 2020-01-01DOI: 10.37904/metal.2020.3534
L. Kander, S. Stejskalová, P. Čížek
Recent increase in output of nuclear power plant has been attained by enlargement of most major components such as pressure vessels. Such large components have almost reached a size limit from the points of manufacturing capacity. In order to solve this problem, it must be beneficial to apply by use of material of higher strength, which brings reduction of pressure vessel thickness and weight A508 Grade 4N is a high nickel pressure vessel steel with relatively high yield strength and a relatively low transition temperature. A study was undertaken to evaluate conventional as well as unconventional material properties of forging made of in our institute. This paper describes results of mechanical properties, structure and fracture behavior including nil-ductility transition temperature.
{"title":"Fracture behaviour, structure and mechanical properties of A508 Gr. 4N Class 3 Grade Steel","authors":"L. Kander, S. Stejskalová, P. Čížek","doi":"10.37904/metal.2020.3534","DOIUrl":"https://doi.org/10.37904/metal.2020.3534","url":null,"abstract":"Recent increase in output of nuclear power plant has been attained by enlargement of most major components such as pressure vessels. Such large components have almost reached a size limit from the points of manufacturing capacity. In order to solve this problem, it must be beneficial to apply by use of material of higher strength, which brings reduction of pressure vessel thickness and weight A508 Grade 4N is a high nickel pressure vessel steel with relatively high yield strength and a relatively low transition temperature. A study was undertaken to evaluate conventional as well as unconventional material properties of forging made of in our institute. This paper describes results of mechanical properties, structure and fracture behavior including nil-ductility transition temperature.","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78767574","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 : 2020-01-01DOI: 10.37904/metal.2020.3665
M. Villanueva, C. Calderon, M. Saldaña, N. Toro
Due to the constant growth of the copper industry, the increase in production costs and complexity in the composition of the feed of the production processes that make up the industry, the analysis of alternatives that improve efficiency by studying the dynamics of the processes represents a significant cost reduction. Then, the generation of analytical models that represent the dynamic behaviour of production processes has the potential to contribute to generating a better understanding of the operating parameters that have a greater impact on the response (s), in addition to identifying operating restrictions and optimal levels of operation. The present work developed a digital model of the SAG milling process by generating multiple regression and quadratic regression models. The relationships between 22 operational variables with production in tons per hour were sampled, and after analysing the impact of the independent variables on the response, water feeding, sump level, percentage of solids in feeding, pebbles and hardness were maintained for fit the analytical models. The multiple linear regression model presents a good fit to the operational data (85.4%), however, the inclusion of the interactions and the quadratic effects of the variables increases the coefficient of determination (93.2%).
{"title":"Modelling a SAG Grinding System through multiples regressions","authors":"M. Villanueva, C. Calderon, M. Saldaña, N. Toro","doi":"10.37904/metal.2020.3665","DOIUrl":"https://doi.org/10.37904/metal.2020.3665","url":null,"abstract":"Due to the constant growth of the copper industry, the increase in production costs and complexity in the composition of the feed of the production processes that make up the industry, the analysis of alternatives that improve efficiency by studying the dynamics of the processes represents a significant cost reduction. Then, the generation of analytical models that represent the dynamic behaviour of production processes has the potential to contribute to generating a better understanding of the operating parameters that have a greater impact on the response (s), in addition to identifying operating restrictions and optimal levels of operation. The present work developed a digital model of the SAG milling process by generating multiple regression and quadratic regression models. The relationships between 22 operational variables with production in tons per hour were sampled, and after analysing the impact of the independent variables on the response, water feeding, sump level, percentage of solids in feeding, pebbles and hardness were maintained for fit the analytical models. The multiple linear regression model presents a good fit to the operational data (85.4%), however, the inclusion of the interactions and the quadratic effects of the variables increases the coefficient of determination (93.2%).","PeriodicalId":18449,"journal":{"name":"METAL 2020 Conference Proeedings","volume":"127 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90387837","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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