The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Akira Okada - One of the best experts on this subject based on the ideXlab platform.
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Surface modification of cemented carbide by eb polishing
Cirp Annals-manufacturing Technology, 2011Co-Authors: Akira Okada, R Kitada, Yasuhiro Okamoto, Yoshiyuki UnoAbstract:Abstract Cemented carbide has many excellent properties. However, it is sometimes difficult to apply conventional Surface Finishing or Surface modification methods for the cemented carbide. The possibility of Surface modification by large-area electron beam irradiation, namely EB polishing was discussed. The Surface structure of the EB polished cemented carbide was observed by TEM. The hardness and the water repellency were tested. Also, the separation force of molded resin from the Surface was measured for evaluating the releasability of the resin. The water repellency and the releasability of the molded resin could be improved by EB polishing, because the Surface structure changed.
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Surface modification of stainless steel for surgical tool by eb polishing
Key Engineering Materials, 2009Co-Authors: Akira Okada, Yoshiyuki Uno, Kunihiko Fujiwara, Hiroaki Watanabe, Kenji DoiAbstract:A new Surface Finishing method by large-area electron beam irradiation (EB-polishing) for stainless steels for orthopedic surgical tool was proposed in our previous paper, and it was shown that high-efficient Surface Finishing was possible by the EB-polishing. In this report, the Surface structure of EB-polished stainless steel is analyzed by TEM and EDX. Also, Surface modification effects such as resistance to corrosion and blood repellency are evaluated. Then, the applicability of the EB-polishing as a new Surface modification method of stainless steel for orthopedic surgical tool is discussed.
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high efficiency Surface Finishing of metal mold by large area electron beam irradiation 3rd report relationship between crater generation and workpiece material
Journal of The Japan Society for Precision Engineering, 2008Co-Authors: Akira Okada, Sadao Sano, Yoshiaki Daichi, Atsushi Kondoh, U N O Yoshiyuki, K UemuraAbstract:A new Finishing process for metal molds by large-area electron beam irradiation (EB polishing) was proposed and the fundamental effects of EB irradiation conditions on Surface Finishing, the Surface modification effect and others were investigated in the previous report. As a result, the Surface roughness on the whole Surface within 60mm in diameter could be reduced from 6μmRz to less than 1μmRz in just a few minutes under a proper condition, and the Surface roughness could be well improved even if the Surface tilting angle is close to 90 degrees. In addition, the corrosion resistance of metal mold Surface could be improved. However, small craters sometimes were generated on the EB irradiated Surface, which might deteriorate the quality of products. In this study, the relationship between crater generation and workpiece material was examined. Experimental results made it clear that the generation of crater and its disappearance were repeated on the Surface with EB irradiation, and the generation of crater greatly depends on the nonmetallic additives in base material, particularly on MnS. Moreover, the impurity of workpiece material also has a significant influence on the crater generation.
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Surface Finishing of stainless steels for orthopedic surgical tools by large area electron beam irradiation
CIRP Annals, 2008Co-Authors: Akira Okada, J A Mcgeough, Kunihiko Fujiwara, K Uemura, Sadao SanoAbstract:Surgical tools and jigs are initially machined by multi-axis milling. Then Surface Finishing is carried out mainly by hand lapping. As these tools undergo repeated use, the removal of burrs, scratches and rust from the Surfaces is also performed manually after each operation. These Finishing processes are time-consuming and costly. In this study, a new Finishing method by large-area electron beam irradiation is proposed. Electron beam (EB) with high energy density can be obtained without focusing the beam, and large-area EB can be used for instantly melting or evaporating the metal Surface. Stainless steel for surgical tools and jigs was treated by the large-area EB irradiation method. The experimental results show that highly efficient Surface smoothing of stainless steels by large-area EB irradiation may be achieved. In addition, the resistance to corrosion and blood repellency can be improved simultaneously with Surface smoothing.
Hans Jürgen Maier - One of the best experts on this subject based on the ideXlab platform.
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Application of mechanical Surface Finishing processes for roughness reduction and fatigue improvement of additively manufactured Ti-6Al-4V parts
International Journal of Fatigue, 2017Co-Authors: S. Bagehorn, J. Wehr, Hans Jürgen MaierAbstract:Abstract Currently, additively manufactured (AM) parts have a high initial Surface roughness after the manufacturing process, which can be a limitation for application in highly stressed and cyclically loaded areas. In the present study, Ti-6Al-4V samples were manufactured by laser beam melting, annealed and hot isostatically pressed afterwards. They showed an initial Surface roughness of R a = 17.9 μm depending on their build direction (45°). Subsequently, four different mechanical Surface Finishing processes were applied separately on plates and fatigue coupons in order to reduce the Surface roughness: Milling, blasting, vibratory grinding and a micro machining process. The effectiveness of each treatment is evaluated with respect to the Surface topography, as well as the fatigue properties based on axial fatigue tests performed in accordance to DIN EN 6072. The initial roughness could often be reduced to values R a 7 cycles).
Yoshiyuki Uno - One of the best experts on this subject based on the ideXlab platform.
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Surface modification of cemented carbide by eb polishing
Cirp Annals-manufacturing Technology, 2011Co-Authors: Akira Okada, R Kitada, Yasuhiro Okamoto, Yoshiyuki UnoAbstract:Abstract Cemented carbide has many excellent properties. However, it is sometimes difficult to apply conventional Surface Finishing or Surface modification methods for the cemented carbide. The possibility of Surface modification by large-area electron beam irradiation, namely EB polishing was discussed. The Surface structure of the EB polished cemented carbide was observed by TEM. The hardness and the water repellency were tested. Also, the separation force of molded resin from the Surface was measured for evaluating the releasability of the resin. The water repellency and the releasability of the molded resin could be improved by EB polishing, because the Surface structure changed.
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Surface modification of stainless steel for surgical tool by eb polishing
Key Engineering Materials, 2009Co-Authors: Akira Okada, Yoshiyuki Uno, Kunihiko Fujiwara, Hiroaki Watanabe, Kenji DoiAbstract:A new Surface Finishing method by large-area electron beam irradiation (EB-polishing) for stainless steels for orthopedic surgical tool was proposed in our previous paper, and it was shown that high-efficient Surface Finishing was possible by the EB-polishing. In this report, the Surface structure of EB-polished stainless steel is analyzed by TEM and EDX. Also, Surface modification effects such as resistance to corrosion and blood repellency are evaluated. Then, the applicability of the EB-polishing as a new Surface modification method of stainless steel for orthopedic surgical tool is discussed.
Sadao Sano - One of the best experts on this subject based on the ideXlab platform.
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high efficiency Surface Finishing of metal mold by large area electron beam irradiation 3rd report relationship between crater generation and workpiece material
Journal of The Japan Society for Precision Engineering, 2008Co-Authors: Akira Okada, Sadao Sano, Yoshiaki Daichi, Atsushi Kondoh, U N O Yoshiyuki, K UemuraAbstract:A new Finishing process for metal molds by large-area electron beam irradiation (EB polishing) was proposed and the fundamental effects of EB irradiation conditions on Surface Finishing, the Surface modification effect and others were investigated in the previous report. As a result, the Surface roughness on the whole Surface within 60mm in diameter could be reduced from 6μmRz to less than 1μmRz in just a few minutes under a proper condition, and the Surface roughness could be well improved even if the Surface tilting angle is close to 90 degrees. In addition, the corrosion resistance of metal mold Surface could be improved. However, small craters sometimes were generated on the EB irradiated Surface, which might deteriorate the quality of products. In this study, the relationship between crater generation and workpiece material was examined. Experimental results made it clear that the generation of crater and its disappearance were repeated on the Surface with EB irradiation, and the generation of crater greatly depends on the nonmetallic additives in base material, particularly on MnS. Moreover, the impurity of workpiece material also has a significant influence on the crater generation.
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Surface Finishing of stainless steels for orthopedic surgical tools by large area electron beam irradiation
CIRP Annals, 2008Co-Authors: Akira Okada, J A Mcgeough, Kunihiko Fujiwara, K Uemura, Sadao SanoAbstract:Surgical tools and jigs are initially machined by multi-axis milling. Then Surface Finishing is carried out mainly by hand lapping. As these tools undergo repeated use, the removal of burrs, scratches and rust from the Surfaces is also performed manually after each operation. These Finishing processes are time-consuming and costly. In this study, a new Finishing method by large-area electron beam irradiation is proposed. Electron beam (EB) with high energy density can be obtained without focusing the beam, and large-area EB can be used for instantly melting or evaporating the metal Surface. Stainless steel for surgical tools and jigs was treated by the large-area EB irradiation method. The experimental results show that highly efficient Surface smoothing of stainless steels by large-area EB irradiation may be achieved. In addition, the resistance to corrosion and blood repellency can be improved simultaneously with Surface smoothing.
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Surface Finishing of die and tool steels via plasma based electron beam irradiation
Journal of Materials Processing Technology, 2006Co-Authors: Z Yu, Zhigang Wang, Kazuo Yamazaki, Sadao SanoAbstract:The plasma-based electron beam (PBEB) irradiation with a maximum diameter of 60 mm has been used to smoothen the workpiece Surface. After PBEB irradiation, the machined Surface roughness is reduced, and its corrosion resistance is improved. However, for die and tool steels, some craters still exist on the Surface after PBEB irradiation, which remain a big problem for the roughness improvement and quality control of the machined Surfaces. In this study, four types of work materials have been tested during PBEB irradiation. The effects of non-metallic inclusions (MnS and carbide) and impurities on the generation of craters were investigated. In addition, craters formed on the work materials with different nitrogen concentrations have also been observed after PBEB irradiation. Finally, a case study is given, and it is found that PBEM irradiation can achieve good Surface finish of die steel materials. (c) 2006 Elsevier B.V. All rights reserved.
Vivekanand Kain - One of the best experts on this subject based on the ideXlab platform.
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high temperature oxidation behavior of aisi 304l stainless steel effect of Surface working operations
Applied Surface Science, 2013Co-Authors: S. Ghosh, Kiran M Kumar, Vivekanand KainAbstract:Abstract The oxidation behavior of grade 304L stainless steel (SS) subjected to different Surface Finishing (machining and grinding) operations was followed in situ by contact electric resistance (CER) and electrochemical impedance spectroscopy (EIS) measurements using controlled distance electrochemistry (CDE) technique in high purity water (conductivity
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effect of Surface Finishing operations on high temperature oxidation behaviour of alloy 800
2013Co-Authors: Geogy J Abraham, Kushal Singla, Sunil B Kumar, Vivekanand KainAbstract:Abstract Abstract Abstract Abstract Alloy 800 is being increasingly used as steam-generator tubing material for nuclear power plants. It is used for nuclear application with different Surface finishes due to operations such as grinding, machining and buffing on the component. This results in a work hardened layer on the Surface that alters the high temperature oxidation behaviour of alloy 800. The studies were aimed at characterizing the work hardened layer of the Surface finished alloy 800 using x-ray diffraction (XRD) and electron back scattered diffraction (EBSD) to understand the residual stress and grain boundary character distribution. Also autoclaving of these alloys at 400 °C in steam showed varied oxide morphology which is observed under scanning electron microscopy -field emission gun (SEM-FEG). The variation in the oxide film formation rate due to the Surface layer is different for different Surface Finishing operation. The oxide film morphology and composition plays an important role in localized corrosion resistance of alloy 800. The oxide film instability results in local breakage which acts as a precursor for stress corrosion cracking initiation in alloy 800.
