Pub Date : 2020-01-01DOI: 10.37904/metal.2020.3625
E. Borisov, K. Starikov, A. Popovich, V. Popovich
The aim of this study was to determine the influence of selective laser melting (SLM) process parameters on the formation of cracks in nickel-based single crystal alloy. Several sets of laser scanning parameters, with varied laser power, scanning speed and hatch distance, thus resulting in different volumetric and linear energy densities, were investigated. The relationship between energy density, specimen densification, cracks formation and evolution of directional microstructure was shown. It was found that higher linear energy density results in fewer cracking and defects. Cracking in lower energy samples was attributed to the formation of thermal shrinkage pores in the interdendritic spaces and precipitation of Ta, Mo and Nb carbides along the dendrites boundaries.
{"title":"CRACKs FORMATION IN Nickel-based single crystal alloy manufactured by SELECTIVE LASER MELTING","authors":"E. Borisov, K. Starikov, A. Popovich, V. Popovich","doi":"10.37904/metal.2020.3625","DOIUrl":"https://doi.org/10.37904/metal.2020.3625","url":null,"abstract":"The aim of this study was to determine the influence of selective laser melting (SLM) process parameters on the formation of cracks in nickel-based single crystal alloy. Several sets of laser scanning parameters, with varied laser power, scanning speed and hatch distance, thus resulting in different volumetric and linear energy densities, were investigated. The relationship between energy density, specimen densification, cracks formation and evolution of directional microstructure was shown. It was found that higher linear energy density results in fewer cracking and defects. Cracking in lower energy samples was attributed to the formation of thermal shrinkage pores in the interdendritic spaces and precipitation of Ta, Mo and Nb carbides along the dendrites boundaries.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85208410","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}
Xiaoxuan Deng, Guoliang Liu, Qiangqiang Wang, Baisong Liu, C. Ji, Haibo Li, Xiao-jing Shao, Guo-sen Zhu
The flow control devices (FCDs) in the tundish play an important role in steel cleanliness and removal of macro-inclusions. To eliminate the spot-like defects during deep-drawing process, the liquid steel samples were taken from tundish in three industrial IF steel heats, and the effect of weir structure in the tundish on the steel cleanliness were evaluated and compared with the aid of ASPEX with the total detection area of over 54 000 mm2 . The results showed that non-metallic inclusions over 5 µm observed in the liquid tundish samples were categorized into two types: type 1: alumina based inclusions and type 2: calcium aluminates. Compared to the tundish without weir, the number density of macro-inclusions reduces by half when furnished with weir. In addition, several large sized calcium aluminates were occasionally found without weir whereas no calcium aluminates were detected with the weir. The mechanism of the inclusion distributions with the weir was proposed based on the experimental results, which shows that the weir act as a baffle that block the large sized inclusions from moving toward the mould. After using the weir in the actual casting practice, the occurrence ratio of spot-like defects was decreased by about 25%.
{"title":"Effect of the weir structure in the tundish on the cleanliness of IF steels and elimination of spot-like defects in deep drawing automobile steel sheets","authors":"Xiaoxuan Deng, Guoliang Liu, Qiangqiang Wang, Baisong Liu, C. Ji, Haibo Li, Xiao-jing Shao, Guo-sen Zhu","doi":"10.1051/metal/2020061","DOIUrl":"https://doi.org/10.1051/metal/2020061","url":null,"abstract":"The flow control devices (FCDs) in the tundish play an important role in steel cleanliness and removal of macro-inclusions. To eliminate the spot-like defects during deep-drawing process, the liquid steel samples were taken from tundish in three industrial IF steel heats, and the effect of weir structure in the tundish on the steel cleanliness were evaluated and compared with the aid of ASPEX with the total detection area of over 54 000 mm2 . The results showed that non-metallic inclusions over 5 µm observed in the liquid tundish samples were categorized into two types: type 1: alumina based inclusions and type 2: calcium aluminates. Compared to the tundish without weir, the number density of macro-inclusions reduces by half when furnished with weir. In addition, several large sized calcium aluminates were occasionally found without weir whereas no calcium aluminates were detected with the weir. The mechanism of the inclusion distributions with the weir was proposed based on the experimental results, which shows that the weir act as a baffle that block the large sized inclusions from moving toward the mould. After using the weir in the actual casting practice, the occurrence ratio of spot-like defects was decreased by about 25%.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"78 1","pages":"609"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84261012","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.2020.3497
Ivana Schnablová, R. Kopřiva, Ondřej Buršík, K. Rusňáková, A. Materna
Current trend of long-term operation of NPP’s for more than 60 years requires assurance of its safety and reliability. One of the solutions how to extend service life of reactor pressure vessel (RPV) is thermal annealing, which became a verified technology and its application in nuclear industry was prompted mainly due to an inability of RPV exchange. At present time, there is no comparable method for RPV internals that are not monitored by surveillance program and their material is exposed to significantly more intense neutron flux than the RPV. Paper presents the thermal annealing as one of the possible solutions to provide and re-establish sufficient mechanical properties of RPV internals during the operation. According to previously obtained results of unirradiated material, two thermal annealing regimes for irradiated experimental material were selected based on the annealing temperatures of 550 and 600 °C. The possibility of recovery of mechanical properties to the level almost corresponding to the initial state by the thermal annealing was studied by hardness testing and static fracture toughness tests before and after the thermal annealing of irradiated material.
{"title":"THERMAL ANNEALING OF WWER – 440 NUCLEAR REACTOR PRESSURE VESSEL INTERNALS MATERIAL","authors":"Ivana Schnablová, R. Kopřiva, Ondřej Buršík, K. Rusňáková, A. Materna","doi":"10.37904/metal.2020.3497","DOIUrl":"https://doi.org/10.37904/metal.2020.3497","url":null,"abstract":"Current trend of long-term operation of NPP’s for more than 60 years requires assurance of its safety and reliability. One of the solutions how to extend service life of reactor pressure vessel (RPV) is thermal annealing, which became a verified technology and its application in nuclear industry was prompted mainly due to an inability of RPV exchange. At present time, there is no comparable method for RPV internals that are not monitored by surveillance program and their material is exposed to significantly more intense neutron flux than the RPV. Paper presents the thermal annealing as one of the possible solutions to provide and re-establish sufficient mechanical properties of RPV internals during the operation. According to previously obtained results of unirradiated material, two thermal annealing regimes for irradiated experimental material were selected based on the annealing temperatures of 550 and 600 °C. The possibility of recovery of mechanical properties to the level almost corresponding to the initial state by the thermal annealing was studied by hardness testing and static fracture toughness tests before and after the thermal annealing of irradiated material.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85852433","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.2020.3659
D. Klimecka-Tatar
Titanium, invariably for decades, is the most promising metallic material used in medicine (implantology). And its suitability is primarily determined by biotolerance, which depends on the preparation of the surface of the elements. This paper assesses the quality control of oxide layers produced on pure (medical) titanium in the process of thermal oxidation in an air atmosphere. The parameters characterizing surface roughness have been used as control parameters. It was noted that the titanium surface undergoes a slight change with short oxidation times, and the oxidation is relatively even in nature. However, with longer oxidation times (more than 45 minutes) roughness parameters change drastically, which is not always beneficial from the point of view of further use.
{"title":"QUality CONTROL BASE ON surface roughness CHARACTERISTIC – OXIDE layer on PURE titanium","authors":"D. Klimecka-Tatar","doi":"10.37904/metal.2020.3659","DOIUrl":"https://doi.org/10.37904/metal.2020.3659","url":null,"abstract":"Titanium, invariably for decades, is the most promising metallic material used in medicine (implantology). And its suitability is primarily determined by biotolerance, which depends on the preparation of the surface of the elements. This paper assesses the quality control of oxide layers produced on pure (medical) titanium in the process of thermal oxidation in an air atmosphere. The parameters characterizing surface roughness have been used as control parameters. It was noted that the titanium surface undergoes a slight change with short oxidation times, and the oxidation is relatively even in nature. However, with longer oxidation times (more than 45 minutes) roughness parameters change drastically, which is not always beneficial from the point of view of further use.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86462855","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.2020.3444
R. Bendikiene, A. Ciuplys, R. Česnavičius, V. Grigas, A. Jutas, A. Bahdanovich, D. N. Marmysh, A. Nasan, Liudmila Shemet, S. Sherbakov
This research paper combines investigation of mechanical properties of austempered ductile cast iron (ADI) and comparison with standard grades of steel and cast iron. Due to the special features of both materials – catsability from cast iron, and toughness from steel, ADI attracts an attention of industry and science because of economic benefits and high performance at the different application areas. Austempered ductile iron was tested on tension where unconventional behaviour was observed: with the increase of tensile strength almost to 1600 MPa the metal became less brittle. Hardness test revealed absence of linear relation between strength and hardness, different hardness values ~ 40 HRC or ~ 55 HRC can be reached with the same tensile strength 1000 – 1200 MPa. After successful tensile tests the main direction of further studies was solving relevant practical wear and fatigue problems in rail-wheel system. The complex practical studies demonstrated that ADI is consistent with heat treated steels including the rail steels: required tensile strength of rail steel ranges from 1180 MPa to 1280 MPa when rolling surface hardness is expected to be in the range of 38 HRC – 44 HRC, whereas tensile strength of ADI was higher, up to 1400 MPa, and hardness slightly higher than of steel, 50 HRC. Herewith the workability of frictional couple cast iron/steel 20MnCr5G exceeded work performance of steel/steel system by 14 %. Specific properties emerged from successful ratio of three elements Mo, Ni, and Cu, and properly chosen austenitization schedule.
{"title":"STUDY OF AUSTEMPERED DUCTILE CAST IRON ENRICHED BY PARTICULAR RATIO OF Nickel, mOLYBDENUM AND COPPER","authors":"R. Bendikiene, A. Ciuplys, R. Česnavičius, V. Grigas, A. Jutas, A. Bahdanovich, D. N. Marmysh, A. Nasan, Liudmila Shemet, S. Sherbakov","doi":"10.37904/metal.2020.3444","DOIUrl":"https://doi.org/10.37904/metal.2020.3444","url":null,"abstract":"This research paper combines investigation of mechanical properties of austempered ductile cast iron (ADI) and comparison with standard grades of steel and cast iron. Due to the special features of both materials – catsability from cast iron, and toughness from steel, ADI attracts an attention of industry and science because of economic benefits and high performance at the different application areas. Austempered ductile iron was tested on tension where unconventional behaviour was observed: with the increase of tensile strength almost to 1600 MPa the metal became less brittle. Hardness test revealed absence of linear relation between strength and hardness, different hardness values ~ 40 HRC or ~ 55 HRC can be reached with the same tensile strength 1000 – 1200 MPa. After successful tensile tests the main direction of further studies was solving relevant practical wear and fatigue problems in rail-wheel system. The complex practical studies demonstrated that ADI is consistent with heat treated steels including the rail steels: required tensile strength of rail steel ranges from 1180 MPa to 1280 MPa when rolling surface hardness is expected to be in the range of 38 HRC – 44 HRC, whereas tensile strength of ADI was higher, up to 1400 MPa, and hardness slightly higher than of steel, 50 HRC. Herewith the workability of frictional couple cast iron/steel 20MnCr5G exceeded work performance of steel/steel system by 14 %. Specific properties emerged from successful ratio of three elements Mo, Ni, and Cu, and properly chosen austenitization schedule.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84328182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of hot-charging temperature (HCT) on the transformation and microstructure evolution of a weathering steel was investigated by metallography and dilatometry. The results show that the microstructure consisted of ferrite and pearlite in all specimens when the HCT was between 500 ∼ 850 °C. The difference was that pearlite amount increased obviously at 750 °C, which is detrimental to the plasticity of steels. The reason for more pearlite is that ferrite and austenite coexisted at 750 °C, which belongs to the dual-phase region temperature. The reversed transformation of ferrite to austenite happened and the pre-existing austenite became coarse during the secondary austenization. The carbon content in fine reversed austenite was relatively low, while the coarse austenite contained higher carbon content, which decomposed into blocky pearlite in the final cooling process. Therefore, to obtain the desirable ferrite phase, the HCT of about 750 °C should be avoided. The results provide theoretical reference for optimizing hot-charging rolling process parameters.
{"title":"Study on the transformation and microstructure evolution during hot-charging rolling process of a weathering steel","authors":"Man Liu, Guang Xu, Guanghui Chen, Zhoutou Wang","doi":"10.1051/metal/2020027","DOIUrl":"https://doi.org/10.1051/metal/2020027","url":null,"abstract":"The effect of hot-charging temperature (HCT) on the transformation and microstructure evolution of a weathering steel was investigated by metallography and dilatometry. The results show that the microstructure consisted of ferrite and pearlite in all specimens when the HCT was between 500 ∼ 850 °C. The difference was that pearlite amount increased obviously at 750 °C, which is detrimental to the plasticity of steels. The reason for more pearlite is that ferrite and austenite coexisted at 750 °C, which belongs to the dual-phase region temperature. The reversed transformation of ferrite to austenite happened and the pre-existing austenite became coarse during the secondary austenization. The carbon content in fine reversed austenite was relatively low, while the coarse austenite contained higher carbon content, which decomposed into blocky pearlite in the final cooling process. Therefore, to obtain the desirable ferrite phase, the HCT of about 750 °C should be avoided. The results provide theoretical reference for optimizing hot-charging rolling process parameters.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"104 1","pages":"304"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80671105","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}
Rupak Ranjan, H. P. Tiwari, P. Srivastava, M. S. Raghuwanshi, A. K. Jaiswal, M. Borkar
In recent past, Jindal Steel & Power Limited, Raigarh unit, has increased the hot metal production capacity by the renovation of the existing blast furnaces. Therefore, the blast furnace coke demand has increased. This excess demand for metallurgical coke production from the existing non-recovery stamp charge coke oven plant was a very tough challenge, because the coke oven plant was already running at rated production capacity. Therefore, to fulfill the requirement of excess coke and to deliver more value to the customers, several initiatives have been taken by the Coke Oven and Technical Services Department within the existing setup. Few approaches had been adopted to increase the productivity of coke by ∼20% without deteriorating the resultant coke quality. This paper describes in details the steps taken to enhance the productivity of non-recovery stamp charge coke oven plant.
{"title":"Enhancement of the productivity of non-recovery stamp charge coke oven plant at JSPL Raigarh","authors":"Rupak Ranjan, H. P. Tiwari, P. Srivastava, M. S. Raghuwanshi, A. K. Jaiswal, M. Borkar","doi":"10.1051/metal/2020074","DOIUrl":"https://doi.org/10.1051/metal/2020074","url":null,"abstract":"In recent past, Jindal Steel & Power Limited, Raigarh unit, has increased the hot metal production capacity by the renovation of the existing blast furnaces. Therefore, the blast furnace coke demand has increased. This excess demand for metallurgical coke production from the existing non-recovery stamp charge coke oven plant was a very tough challenge, because the coke oven plant was already running at rated production capacity. Therefore, to fulfill the requirement of excess coke and to deliver more value to the customers, several initiatives have been taken by the Coke Oven and Technical Services Department within the existing setup. Few approaches had been adopted to increase the productivity of coke by ∼20% without deteriorating the resultant coke quality. This paper describes in details the steps taken to enhance the productivity of non-recovery stamp charge coke oven plant.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"104 1","pages":"617"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80823528","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}
Fan Lifeng, Xingyuan Zhao, Li-jun Xiao, Jiao Huang, Y. Zhang
The medium temperature reheating and two-stage cold rolling process were adopted to produce industrialized Grain-oriented silicon steel. Results showed there were three sections (surface layer, transition layer and central layer) along the thickness direction on hot rolled sheets. Surface layer was occupied by complete recrystallization grains with average grain size 42.81 µm, while the central layer mainly consisted of fibrous microstructure. The Goss texture appeared only on surface layer with content 3.44%∼3.65%. After the first cold rolling with 72% reduction and decarburization annealing, the primary recrystallization occurred and average grains size reached 19.0 µm, simultaneously accompanied with texture rotated to λ, γ fiber texture and Goss texture dropped to 2.89%. Adopting the second cold rolling with 58% reduction, the cold rolled sheet consisted of deformed fiber microstructure and the texture maintained γ fiber texture with a peak at {111} . The precipitates in hot rolled sheets comprised Cu2 S and few AlN, and the average particle size was ∼14 nm. The inhibitors in the decarburization annealing sheet were mainly AlN, Cu2 S, MnS and their composite precipitation, which were spherical or massive with the average particle size ∼21 nm. The single Goss oriented grains with average grain size 9.41 mm were obtained after high temperature annealing, and the intensity reached 873.30. The final magnetic properties were: B8 = 1.865 T and P1.7/50 = 1.124 W/kg, which met the requirement of 27Q120.
{"title":"Evolution of microstructure, texture and inhibitor of medium temperature grain-oriented silicon steel","authors":"Fan Lifeng, Xingyuan Zhao, Li-jun Xiao, Jiao Huang, Y. Zhang","doi":"10.1051/metal/2020050","DOIUrl":"https://doi.org/10.1051/metal/2020050","url":null,"abstract":"The medium temperature reheating and two-stage cold rolling process were adopted to produce industrialized Grain-oriented silicon steel. Results showed there were three sections (surface layer, transition layer and central layer) along the thickness direction on hot rolled sheets. Surface layer was occupied by complete recrystallization grains with average grain size 42.81 µm, while the central layer mainly consisted of fibrous microstructure. The Goss texture appeared only on surface layer with content 3.44%∼3.65%. After the first cold rolling with 72% reduction and decarburization annealing, the primary recrystallization occurred and average grains size reached 19.0 µm, simultaneously accompanied with texture rotated to λ, γ fiber texture and Goss texture dropped to 2.89%. Adopting the second cold rolling with 58% reduction, the cold rolled sheet consisted of deformed fiber microstructure and the texture maintained γ fiber texture with a peak at {111} . The precipitates in hot rolled sheets comprised Cu2 S and few AlN, and the average particle size was ∼14 nm. The inhibitors in the decarburization annealing sheet were mainly AlN, Cu2 S, MnS and their composite precipitation, which were spherical or massive with the average particle size ∼21 nm. The single Goss oriented grains with average grain size 9.41 mm were obtained after high temperature annealing, and the intensity reached 873.30. The final magnetic properties were: B8 = 1.865 T and P1.7/50 = 1.124 W/kg, which met the requirement of 27Q120.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"57 1","pages":"510"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78859790","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.2020.3543
B. Eremiáš, L. Mindos, L. Turek
The possible effects on the protective performance of ZRP modified by combination of Zn dust with aluminium or carbon type fillers were investigated using electrochemical noise analysis (ENA). The role of different oxygen diffusion characteristics (identified on tested coating systems with ENA) on delamination tendency was tested during 168 hrs immersion tests in 0.05 M NaCl. It was shown the protective performance of tested type of coating systems can be changing with immersion time rather differently in relation to different ability of polymer matrix with the Zn/Al or Zn/C particles combination for oxygen transport to the coating/steel interface.
利用电化学噪声分析(ENA)研究了锌粉与铝或碳型填料复合改性ZRP对其防护性能可能产生的影响。在0.05 M NaCl中浸泡168小时，测试了不同的氧扩散特性(在测试的ENA涂层体系中确定)对分层倾向的影响。结果表明，不同类型的聚合物基体与Zn/Al或Zn/C颗粒组合向涂层/钢界面输送氧的能力不同，其防护性能随浸泡时间的变化有较大差异。
{"title":"THE APPLICATION OF ENA FOR COMPARISON OF PROTECTIVE PERFORMANCE OF ZRP MODIFIED BY COMBINATION OF Zn DUST WITH ALUMINIUM OR CARBON TYPE FILLERS","authors":"B. Eremiáš, L. Mindos, L. Turek","doi":"10.37904/metal.2020.3543","DOIUrl":"https://doi.org/10.37904/metal.2020.3543","url":null,"abstract":"The possible effects on the protective performance of ZRP modified by combination of Zn dust with aluminium or carbon type fillers were investigated using electrochemical noise analysis (ENA). The role of different oxygen diffusion characteristics (identified on tested coating systems with ENA) on delamination tendency was tested during 168 hrs immersion tests in 0.05 M NaCl. It was shown the protective performance of tested type of coating systems can be changing with immersion time rather differently in relation to different ability of polymer matrix with the Zn/Al or Zn/C particles combination for oxygen transport to the coating/steel interface.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86888255","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.2020.3466
P. Opěla, I. Schindler, S. Rusz, V. Ševčák, I. Mamuzic
A hot flow curve approximation performed via flow stress models as well as artificial neural networks requires precisely estimated constants. This estimation is in the case of highly-nonlinear issues often solved via gradient optimization algorithms. Nevertheless, by natural processes or physical laws inspired approaches (metaheuristic algorithms) are also of high interest. In the submitted manuscript, three selected metaheuristic algorithms were compared under the approximation of an experimental hot flow curve dataset via the wellknown Hensel-Spittel relationship. One often used gradient algorithm was also included into this comparison. Results have showed that the metaheuristic algorithms are useful if such complex approximation model is applied and no estimate of material constants from a previous approximation issue is used. On the other hand, if this estimation exists, the gradient algorithms should provide a better solution.
{"title":"ON THE METAHEURISTIC OPTIMIZATION ALGORITHMS IN THE STRUGGLE FOR THE HOT FLOW CURVE APPROXIMATION ACCURACY","authors":"P. Opěla, I. Schindler, S. Rusz, V. Ševčák, I. Mamuzic","doi":"10.37904/metal.2020.3466","DOIUrl":"https://doi.org/10.37904/metal.2020.3466","url":null,"abstract":"A hot flow curve approximation performed via flow stress models as well as artificial neural networks requires precisely estimated constants. This estimation is in the case of highly-nonlinear issues often solved via gradient optimization algorithms. Nevertheless, by natural processes or physical laws inspired approaches (metaheuristic algorithms) are also of high interest. In the submitted manuscript, three selected metaheuristic algorithms were compared under the approximation of an experimental hot flow curve dataset via the wellknown Hensel-Spittel relationship. One often used gradient algorithm was also included into this comparison. Results have showed that the metaheuristic algorithms are useful if such complex approximation model is applied and no estimate of material constants from a previous approximation issue is used. On the other hand, if this estimation exists, the gradient algorithms should provide a better solution.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78698246","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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