Pub Date : 2020-01-01DOI: 10.37904/metal.2020.3559
J. Vavřík, T. Hrbáčková, P. Salvetr, M. Brázda
This paper explores a protective stellite coating on 1.4922 martensitic steel. Stellite coatings are often used to improve the properties of the part’s surface. The microstructure of the sample was analysed and its hardness measured. Protective coatings enhance mechanical and corrosion properties of the substrate, and thus extend the life of the respective part. They can be created by galvanizing, ion implantation, thermal spraying, or by more recent methods, such as laser cladding, DED (directed energy deposition) and others. DED is one of the metal deposition processes that fall in the AM category (additive manufacturing). It was used to deposit the protective coating in the present study. DED is an evolving technology which is suitable not only for prototype development, but also for promising applications involving surface treatment and repairs of functional parts. DED uses a laser beam as a thermal source to melt powder which is blown concentrically with the laser beam and the protective gas. The unique advantage of this method is a very good cohesion and bonding between the substrate and the deposited layer with a smaller HAZ (heat-affected zone). It produces comparatively few inhomogeneities and defects, which makes it a promising technique for protective layer applications. Stellite was chosen as a protective coating material because this group of alloys exhibits excellent properties such as high wear resistance, abrasion resistance, superior corrosion resistance and erosion resistance. These are relevant in many industrial sectors, such as power generation, aerospace and others. Stellite 21 was used in the present study.
{"title":"Stellite coating deposited by directED energy deposition","authors":"J. Vavřík, T. Hrbáčková, P. Salvetr, M. Brázda","doi":"10.37904/metal.2020.3559","DOIUrl":"https://doi.org/10.37904/metal.2020.3559","url":null,"abstract":"This paper explores a protective stellite coating on 1.4922 martensitic steel. Stellite coatings are often used to improve the properties of the part’s surface. The microstructure of the sample was analysed and its hardness measured. Protective coatings enhance mechanical and corrosion properties of the substrate, and thus extend the life of the respective part. They can be created by galvanizing, ion implantation, thermal spraying, or by more recent methods, such as laser cladding, DED (directed energy deposition) and others. DED is one of the metal deposition processes that fall in the AM category (additive manufacturing). It was used to deposit the protective coating in the present study. DED is an evolving technology which is suitable not only for prototype development, but also for promising applications involving surface treatment and repairs of functional parts. DED uses a laser beam as a thermal source to melt powder which is blown concentrically with the laser beam and the protective gas. The unique advantage of this method is a very good cohesion and bonding between the substrate and the deposited layer with a smaller HAZ (heat-affected zone). It produces comparatively few inhomogeneities and defects, which makes it a promising technique for protective layer applications. Stellite was chosen as a protective coating material because this group of alloys exhibits excellent properties such as high wear resistance, abrasion resistance, superior corrosion resistance and erosion resistance. These are relevant in many industrial sectors, such as power generation, aerospace and others. Stellite 21 was used in the present study.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"20 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72630306","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}
In this article, based on the actual monitored temperature data from mold copper plate with a dense thermocouple layout and the measured magnetic flux density values in a CSP thin-slab mold, the local heat flux and thin-slab solidification features in the funnel-type mold with electromagnetic braking are analyzed. The differences of local heat flux, fluid flow and solidified shell growth features between two steel grades of Q235B with carbon content of 0.19%C and DC01 of 0.03%C under varying operation conditions are discussed. The results show the maximum transverse local heat flux is near the meniscus region of over 0.3 m away from the center of the wide face, which corresponds to the upper flow circulation and the large turbulent kinetic energy in a CSP funnel-type mold. The increased slab width and low casting speed can reduce the fluctuation of the transverse local heat flux near the meniscus. There is a decreased transverse local heat flux in the center of the wide face after the solidified shell is pulled through the transition zone from the funnel-curve to the parallel-cure zone. In order to achieve similar metallurgical effects, the braking strength should increase with the increase of casting speed and slab width. Using the strong EMBr field in a lower casting speed might reverse the desired effects. There exist some differences of solidified shell thinning features for different steel grades in the range of the funnel opening region under the measured operating conditions, which may affect the optimization of the casting process in a CSP caster.
{"title":"Numerical analysis of local heat flux and thin-slab solidification in a CSP funnel-type mold with electromagnetic braking","authors":"He-ping Liu, Jianjun Zhang, H. Tao, Hui Zhang","doi":"10.1051/metal/2020044","DOIUrl":"https://doi.org/10.1051/metal/2020044","url":null,"abstract":"In this article, based on the actual monitored temperature data from mold copper plate with a dense thermocouple layout and the measured magnetic flux density values in a CSP thin-slab mold, the local heat flux and thin-slab solidification features in the funnel-type mold with electromagnetic braking are analyzed. The differences of local heat flux, fluid flow and solidified shell growth features between two steel grades of Q235B with carbon content of 0.19%C and DC01 of 0.03%C under varying operation conditions are discussed. The results show the maximum transverse local heat flux is near the meniscus region of over 0.3 m away from the center of the wide face, which corresponds to the upper flow circulation and the large turbulent kinetic energy in a CSP funnel-type mold. The increased slab width and low casting speed can reduce the fluctuation of the transverse local heat flux near the meniscus. There is a decreased transverse local heat flux in the center of the wide face after the solidified shell is pulled through the transition zone from the funnel-curve to the parallel-cure zone. In order to achieve similar metallurgical effects, the braking strength should increase with the increase of casting speed and slab width. Using the strong EMBr field in a lower casting speed might reverse the desired effects. There exist some differences of solidified shell thinning features for different steel grades in the range of the funnel opening region under the measured operating conditions, which may affect the optimization of the casting process in a CSP caster.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"19 1","pages":"602"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73368600","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.2020.3662
Jaroslav Sláčala, H. Špačková, M. Mensík, Petra Svobodova, Tomáš Barčák
The introduction of a high degree of automation, such as robotic manipulation in metallurgical processes is no longer a difficult discipline with limited use although these processes are characterized by a specific environment that sets high demands on automation. Forging is a manufacturing process involving the shaping of metal using localized compressive forces where robot manipulates step by step through the forging process until the finished workpiece is removed from a forging press. In many such production lines people are still working in difficult working conditions with a high risk of injury. By replacing the worker with robots, the process becomes much safer and more efficient. Process automation in extreme environmental conditions requires a specific kind of know-how. The implementation of robots into metallurgical processes is a major challenge for robot manufacturers in terms of the robot’s service life. The paper summarizes and shows the fundamental requirements that must be considered before designing and integrating robotic systems into these particular conditions.
{"title":"Use of robotic manipulation systems in automation of FORGING processes","authors":"Jaroslav Sláčala, H. Špačková, M. Mensík, Petra Svobodova, Tomáš Barčák","doi":"10.37904/metal.2020.3662","DOIUrl":"https://doi.org/10.37904/metal.2020.3662","url":null,"abstract":"The introduction of a high degree of automation, such as robotic manipulation in metallurgical processes is no longer a difficult discipline with limited use although these processes are characterized by a specific environment that sets high demands on automation. Forging is a manufacturing process involving the shaping of metal using localized compressive forces where robot manipulates step by step through the forging process until the finished workpiece is removed from a forging press. In many such production lines people are still working in difficult working conditions with a high risk of injury. By replacing the worker with robots, the process becomes much safer and more efficient. Process automation in extreme environmental conditions requires a specific kind of know-how. The implementation of robots into metallurgical processes is a major challenge for robot manufacturers in terms of the robot’s service life. The paper summarizes and shows the fundamental requirements that must be considered before designing and integrating robotic systems into these particular conditions.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"183 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77544719","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.2020.3454
J. Růžička, Mario Machů, Jan Haščin
{"title":"ARCHaEOMETALLURGY – experimental ferrous metallurgy","authors":"J. Růžička, Mario Machů, Jan Haščin","doi":"10.37904/metal.2020.3454","DOIUrl":"https://doi.org/10.37904/metal.2020.3454","url":null,"abstract":"","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","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":"73891087","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.2020.3480
B. Behrens, J. Ursinus, C. Büdenbender, K. Brunotte, F. Nürnberger, E. Demler, H. Maier
In order to reduce the number of process steps of steel forging processes. and thus also tool wear and process costs, tailored preform geometries can be produced by casting. By only one subsequent forming operation it is possible to improve the casting microstructure, eliminate possible defects and achieve the required mechanical properties. To evaluate the properties of the cast microstructure and the closure of possible casting defects during warm/hot forming, cylindrical steel billets (C45/1.0503) were produced by sand casting and then upset in a hydraulic press. Global plastic strain φ was varied between 0.3 and 0.7 while forging temperatures of 600 °C and 1200 °C were applied to detect possible temperature effects. Conventional rolled bar material formed under the same conditions was used as a reference. After forming, the specimens were tempered and the mechanical properties were determined by tensile tests (ISO 6892-1) and notch impact tests (similar to ISO 148-1). The microstructures were examined by metallographic analysis while defects were characterised using an optical wide-area 3D measurement system and digital image processing. It could be observed that the ultimate tensile strength of the cast-forged specimens depends on the forming temperature and is about 15 % lower in comparison to the reference material at a forming temperature of 600 °C and 5 % lower at 1200 °C, respectively. The impact energies show a strong dependence on plastic strain for both, the castforged and reference specimens. The values of the mechanical properties of the reference specimens were higher than those of the cast-forged specimens. These results allow a deeper understanding of the cast-forging of steel and will contribute to the cast-forging design of more complex steel parts.
{"title":"Porosity in Hot Formed Cast Steel","authors":"B. Behrens, J. Ursinus, C. Büdenbender, K. Brunotte, F. Nürnberger, E. Demler, H. Maier","doi":"10.37904/metal.2020.3480","DOIUrl":"https://doi.org/10.37904/metal.2020.3480","url":null,"abstract":"In order to reduce the number of process steps of steel forging processes. and thus also tool wear and process costs, tailored preform geometries can be produced by casting. By only one subsequent forming operation it is possible to improve the casting microstructure, eliminate possible defects and achieve the required mechanical properties. To evaluate the properties of the cast microstructure and the closure of possible casting defects during warm/hot forming, cylindrical steel billets (C45/1.0503) were produced by sand casting and then upset in a hydraulic press. Global plastic strain φ was varied between 0.3 and 0.7 while forging temperatures of 600 °C and 1200 °C were applied to detect possible temperature effects. Conventional rolled bar material formed under the same conditions was used as a reference. After forming, the specimens were tempered and the mechanical properties were determined by tensile tests (ISO 6892-1) and notch impact tests (similar to ISO 148-1). The microstructures were examined by metallographic analysis while defects were characterised using an optical wide-area 3D measurement system and digital image processing. It could be observed that the ultimate tensile strength of the cast-forged specimens depends on the forming temperature and is about 15 % lower in comparison to the reference material at a forming temperature of 600 °C and 5 % lower at 1200 °C, respectively. The impact energies show a strong dependence on plastic strain for both, the castforged and reference specimens. The values of the mechanical properties of the reference specimens were higher than those of the cast-forged specimens. These results allow a deeper understanding of the cast-forging of steel and will contribute to the cast-forging design of more complex steel parts.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81120118","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.2020.3521
V. Makarevičius, A. Baltušnikas, I. Lukosiute, Rita Kriūkienė, A. Grybėnas
Ferritic-martensitic heat-resistant steels are used for high-temperature service applications in power plants and the petrochemical industry due to its high strength and creep properties at high temperatures. After the long-term operation under, structural changes are taking place, such as coarsening of precipitates and migration of alloying elements within carbides, leading to M23C6 carbide lattice expansion. The thermal aging effect on the structural changes of M23C6 carbide for P91 (9Cr, 1Mo) and P5 (5Cr, 0.5 Mo) steel was investigated after exposure up to 234 days at 700 °C. The electrochemical extraction method was used to extract carbide precipitates from the steel. The identification of alloy carbides and calculation of the M23C6 lattice parameter changes have been accomplished by XRD analysis using crystal structure parameters evaluation and Rietveld refinement method. Microstructure evolution and elemental composition changes were studied by SEM-EDX microanalysis. The chromium and molybdenum content in the M23C6 carbide, determined by SEM/EDX steadily, changes and approaches equilibrium as aging time increases. X-ray diffraction measurements show that the M23C6 carbide crystal lattice parameter increases at high-temperature exposure due to enhanced diffusion of alloying elements from the matrix into a carbide lattice. When the equilibrium for diffusion of the alloying elements is reached, the lattice parameter stops growing. The study shows a significant difference in aging behavior. The obtained knowledge of alloying elements diffusion and M23C6 lattice parameter transformation changes could be used as an indicator for the assessment of heat resistant steel after the long term service.
{"title":"EFFECT OF THERMAL AGING ON STRUCTURAL CHANGES IN P91 AND P5 HEAT RESISTANT STEELS","authors":"V. Makarevičius, A. Baltušnikas, I. Lukosiute, Rita Kriūkienė, A. Grybėnas","doi":"10.37904/metal.2020.3521","DOIUrl":"https://doi.org/10.37904/metal.2020.3521","url":null,"abstract":"Ferritic-martensitic heat-resistant steels are used for high-temperature service applications in power plants and the petrochemical industry due to its high strength and creep properties at high temperatures. After the long-term operation under, structural changes are taking place, such as coarsening of precipitates and migration of alloying elements within carbides, leading to M23C6 carbide lattice expansion. The thermal aging effect on the structural changes of M23C6 carbide for P91 (9Cr, 1Mo) and P5 (5Cr, 0.5 Mo) steel was investigated after exposure up to 234 days at 700 °C. The electrochemical extraction method was used to extract carbide precipitates from the steel. The identification of alloy carbides and calculation of the M23C6 lattice parameter changes have been accomplished by XRD analysis using crystal structure parameters evaluation and Rietveld refinement method. Microstructure evolution and elemental composition changes were studied by SEM-EDX microanalysis. The chromium and molybdenum content in the M23C6 carbide, determined by SEM/EDX steadily, changes and approaches equilibrium as aging time increases. X-ray diffraction measurements show that the M23C6 carbide crystal lattice parameter increases at high-temperature exposure due to enhanced diffusion of alloying elements from the matrix into a carbide lattice. When the equilibrium for diffusion of the alloying elements is reached, the lattice parameter stops growing. The study shows a significant difference in aging behavior. The obtained knowledge of alloying elements diffusion and M23C6 lattice parameter transformation changes could be used as an indicator for the assessment of heat resistant steel after the long term service.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","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":"81968387","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.2020.3517
M. Brázda, P. Salvetr, J. Dlouhý, J. Vavřík
This work focuses on the effect of laser power on the proportion of austenite and ferrite in duplex steel SAF 2507. Duplex steels combine the advantages of ferritic and austenitic steels, preferably with an optimal proportion of austenite and ferrite. The effect of laser beam power in direct laser deposition on this proportion of microstructure constituents was studied. The proportion also has an impact on mechanical and corrosion properties, which are essential for this type of steel. Duplex steels are often used in corrosive environments and their mechanical properties and corrosion resistance depend on the proportion of austenite and ferrite. Direct laser deposition (DED) was used for making samples. DED operates on the principle of laser melting of a powder which is carried by the shielding gas into a nozzle. This technology can be used as an additive manufacturing process as well as for surface repairs and modification of components. The samples in this experimental study were printed using several different fixed outputs and the same intervals. One sample was printed using the machine’s automatic mode. Microstructural analysis was performed using EBSD, EDS and light microscopy. The proportion of austenite and ferrite was measured by X-ray diffraction (XRD analysis). The differences in the proportion of ferrite and austenite were minimal, on the order of several percentage points.
{"title":"Influence of laser power in direct laser deposition on the proportion of ferrite and austenite in duplex steel SAF2507","authors":"M. Brázda, P. Salvetr, J. Dlouhý, J. Vavřík","doi":"10.37904/metal.2020.3517","DOIUrl":"https://doi.org/10.37904/metal.2020.3517","url":null,"abstract":"This work focuses on the effect of laser power on the proportion of austenite and ferrite in duplex steel SAF 2507. Duplex steels combine the advantages of ferritic and austenitic steels, preferably with an optimal proportion of austenite and ferrite. The effect of laser beam power in direct laser deposition on this proportion of microstructure constituents was studied. The proportion also has an impact on mechanical and corrosion properties, which are essential for this type of steel. Duplex steels are often used in corrosive environments and their mechanical properties and corrosion resistance depend on the proportion of austenite and ferrite. Direct laser deposition (DED) was used for making samples. DED operates on the principle of laser melting of a powder which is carried by the shielding gas into a nozzle. This technology can be used as an additive manufacturing process as well as for surface repairs and modification of components. The samples in this experimental study were printed using several different fixed outputs and the same intervals. One sample was printed using the machine’s automatic mode. Microstructural analysis was performed using EBSD, EDS and light microscopy. The proportion of austenite and ferrite was measured by X-ray diffraction (XRD analysis). The differences in the proportion of ferrite and austenite were minimal, on the order of several percentage points.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82211863","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}
Ping Shen, Lei Zhou, Qian-kun Yang, Zhi-qi Zeng, Ke-nan Ai, Jianxun Fu
In 38MnVS6 steel, the morphology of sulfide inclusion has a strong influence on the fatigue life and machinability of the steel. In most cases, the MnS inclusions show strip morphology after rolling, which significantly affects the steel quality. Usually, the MnS inclusion with a spherical morphology is the best morphology for the steel quality. In the present work, tellurium was applied to 38MnVS6 micro-alloyed steel to control the MnS inclusion. Trace tellurium was added into 38MnVS6 steel and the effect of Te on the morphology, composition, size and distribution of MnS inclusions were investigated. Experimental results show that with the increase of Te content, the equivalent diameter and the aspect ratio of inclusion decrease strikingly, and the number of inclusions with small aspect ratio increases. The inclusions are dissociated and spherized. The SEM-EDS analysis indicates that the trace Te mainly dissolves in MnS inclusion. Once the MnS is saturated with Te, MnTe starts to generate and wraps MnS. The critical Te/S value for the formation of MnTe in the 38MnV6 steel is determined to be approximately 0.075. With the increase of Te/S ratio, the aspect ratio of MnS inclusion decreases and gradually reaches a constant level. The Te/S value in the 38MnVS6 steel corresponding to the change of aspect ratio from decreasing to constant ranges from 0.096 to 0.255. This is most likely to be caused by the saturation of Te in the MnS inclusion. After adding Te in the steel, rod-like MnS inclusion is modified to small inclusion and the smaller the MnS inclusion, the lower the aspect ratio.
{"title":"Modification of MnS inclusion by tellurium in 38MnVS6 micro-alloyed steel","authors":"Ping Shen, Lei Zhou, Qian-kun Yang, Zhi-qi Zeng, Ke-nan Ai, Jianxun Fu","doi":"10.1051/metal/2020066","DOIUrl":"https://doi.org/10.1051/metal/2020066","url":null,"abstract":"In 38MnVS6 steel, the morphology of sulfide inclusion has a strong influence on the fatigue life and machinability of the steel. In most cases, the MnS inclusions show strip morphology after rolling, which significantly affects the steel quality. Usually, the MnS inclusion with a spherical morphology is the best morphology for the steel quality. In the present work, tellurium was applied to 38MnVS6 micro-alloyed steel to control the MnS inclusion. Trace tellurium was added into 38MnVS6 steel and the effect of Te on the morphology, composition, size and distribution of MnS inclusions were investigated. Experimental results show that with the increase of Te content, the equivalent diameter and the aspect ratio of inclusion decrease strikingly, and the number of inclusions with small aspect ratio increases. The inclusions are dissociated and spherized. The SEM-EDS analysis indicates that the trace Te mainly dissolves in MnS inclusion. Once the MnS is saturated with Te, MnTe starts to generate and wraps MnS. The critical Te/S value for the formation of MnTe in the 38MnV6 steel is determined to be approximately 0.075. With the increase of Te/S ratio, the aspect ratio of MnS inclusion decreases and gradually reaches a constant level. The Te/S value in the 38MnVS6 steel corresponding to the change of aspect ratio from decreasing to constant ranges from 0.096 to 0.255. This is most likely to be caused by the saturation of Te in the MnS inclusion. After adding Te in the steel, rod-like MnS inclusion is modified to small inclusion and the smaller the MnS inclusion, the lower the aspect ratio.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"20 1","pages":"615"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87131548","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.2020.3549
A. Abrashov, A. Kolesnikova, N. Grigoryan, T. Vagramyan
Recently, as an alternative to chromate protective layers at aluminum and its alloys, worldwide are used nanoscale adhesive coatings, obtained from hexafluorozirconic and hexafluorotitanic acids. The present study is devoted to the technology of development of these coatings. The process of deposition of titanium, zirconium-containing coatings at aluminum alloy 5556 is developed. In the process of performing the work, the basic patterns of coating formation were identified. The solution composition and process parameters were optimized, and the physicochemical properties were investigated. It is shown that passivation of aluminum alloy 5556 in a titanium,zirconium-containing solution increases its corrosion resistance to pitting corrosion. These coatings can replace chromate coatings because of good ability to resist corrosion. It was found that the thickness of titanium-, zirconium-containing coatings is about 100 nm.
{"title":"CHROMATE-FREE CHEMICAL CONVERSION COATINGS ON ALUMINUM ALLOY 5556","authors":"A. Abrashov, A. Kolesnikova, N. Grigoryan, T. Vagramyan","doi":"10.37904/metal.2020.3549","DOIUrl":"https://doi.org/10.37904/metal.2020.3549","url":null,"abstract":"Recently, as an alternative to chromate protective layers at aluminum and its alloys, worldwide are used nanoscale adhesive coatings, obtained from hexafluorozirconic and hexafluorotitanic acids. The present study is devoted to the technology of development of these coatings. The process of deposition of titanium, zirconium-containing coatings at aluminum alloy 5556 is developed. In the process of performing the work, the basic patterns of coating formation were identified. The solution composition and process parameters were optimized, and the physicochemical properties were investigated. It is shown that passivation of aluminum alloy 5556 in a titanium,zirconium-containing solution increases its corrosion resistance to pitting corrosion. These coatings can replace chromate coatings because of good ability to resist corrosion. It was found that the thickness of titanium-, zirconium-containing coatings is about 100 nm.","PeriodicalId":21337,"journal":{"name":"Revue De Metallurgie-cahiers D Informations Techniques","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87433875","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.2020.3666
A. Pawliczek, Pavel Kološ, Štefan Kolumber
The aim of the paper is to analyze and describe recent application of management tools in the enterprises worldwide including their utilization and trends in timeline compared to industrial companies in Olomouc region, Czech Republic. The main data source for presented paper is the research performed by Bain & Company, Inc. (BC) which concentrates on surveying of management tools in companies worldwide since the year 1993, while primary research was performed by authors in companies that produces and customizes metal parts for automotive and aerospace industry. The motivation behind this paper is based on effort to make students and academics in management focus on most recent and powerful management tools to boost successful business. The latest survey of BC has more than 14,700 respondents from more than 70 countries in North America, Europe, Asia, Africa, the Middle East and Latin America, and is probably the most comprehensive systematic long-term study in the world. The management tools in the top ten list vary in time, but four of them remain since 1993 (however some of them temporarily disappeared): Benchmarking, Customer satisfaction, Total quality management and Vision and mission statement.
本文的目的是分析和描述最近的应用管理工具在全球范围内的企业，包括他们的利用和趋势的时间线相比，在奥洛穆茨地区的工业公司，捷克共和国。本文的主要数据来源是Bain & Company, Inc. (BC)进行的研究，该研究集中于1993年以来全球公司管理工具的调查，而主要研究是由作者在汽车和航空航天工业生产和定制金属零件的公司进行的。这篇论文背后的动机是基于努力使学生和学者在管理集中在最新的和强大的管理工具，以促进成功的业务。BC的最新调查有来自北美、欧洲、亚洲、非洲、中东和拉丁美洲70多个国家的14700多名受访者，可能是世界上最全面、系统的长期研究。排名前十的管理工具随着时间的推移而变化，但其中四个自1993年以来一直存在(尽管其中一些暂时消失了):基准管理、客户满意度、全面质量管理和愿景和使命声明。
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