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Volume 15, Issue 1
Displaying 1-5 of 5 articles from this issue
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Hisashi Suzuki, Kozi Hayashi1968 Volume 15 Issue 1 Pages 1-4
Published: January 25, 1968
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSInfluences of low temperature annealing on the properties of WC-TiC-10%Co alloys having various carbon and titanium carbide contents were studied. Specimens were vacuum-sintered at 1400 and 1430°C for 1 hr, furnace-cooled to room temperature and subsequently vacuumannealed at 800°C for 2.5-150 hr. Some properties of the alloys influenced by the annealing, such as lattice parameters of γ and β phases, saturation magnetization, density, hardness and transverse-rupture strength were determined. The results obtained were as follows: (1) The dissolved W in γ phase in the alloys (free from either η phase or free carbon phase) precipitated in the form of Co3W. The amount of precipitation increased with decreasing carbon content in the alloys. (2) The rate of precipitation was larger than those in WC-Co and WC-TaC-Co alloys. (3) However, transverse-rupture strength of the alloys was not affected by the annealing, differing from the cases in WC-Co and WC-TaC-Co alloys. (4) No changes in density, hardness and saturation magnetization of the alloys were observed.View full abstractDownload PDF (2713K) -
Toranosuke Kawaguchi, Hiroshi Yamamoto, Masaaki Ishiyama, Nakamura Mas ...1968 Volume 15 Issue 1 Pages 5-13
Published: January 25, 1968
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe Sendust alloy sheet (Fe-Al-Si system) is too hard to make thin sheet by rolling. The authors succeeded previously in the manufacturing of Sendust sheets by the powder-rolling. (The Journal of the Japan Society of Powder and Powder Metallurgy. Vol.14, No.1, 1967).
The authors have tried to apply the new process of electric discharge sintering to the production of the Sendust alloy thin sheet and have succeeded. This process does not need both special atmosphere and furnace, and can produce thin sheets with free size and thickness. The sintering time in air is shorter as much as a few minutes.
The characteristics of Sendust sheets produced by electric discharge sintering process were compared with those by powder rolling and vacuum sintering (powder metallurgy) and it has been cleared that the electric discharge sintering process is best.
The optimum operating conditions in this process, such as discharging current, discharging time, and pressing pressure are very important to get the best sheets.
In this report, the optimum operating condition to make the Sendust alloy thin sheet and, the measured characteristics, such as (μm, BHe, Br, B10), electric (ρ), and mechanical (hardness) properties are described.View full abstractDownload PDF (6029K) -
Kazo Murakami, Tsuneo Takeda, Nobujiro Tsuchiya1968 Volume 15 Issue 1 Pages 14-18
Published: January 25, 1968
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe WC-TaC-Co alloys containing less than 5%TaC (sintered at 1350°C or 1400°C for lhr) were used as specimens. Their hardness, transverse-rupture strength, density and microstructures were examined, and the effects of the abnormal structure, i.e., spotty structure of tantalum carbide phase on the mechanical properties were studied. Main results obtained were as follows :
(1) The abnormal structure was observed only in the WC-TaC-Co alloys containing a small amount of tantalum carbide. In WC-TaC-10% Co and WC-TaC-20%Co alloys, the said structure was observed when the tantalum carbide content was less than about 0.9%o and 1.6%, respectively.
(2) Hardness and density of the alloy were not affected but transverse-rupture strength was sharply reduced by the formation of the abnormal structure.
(3) Therefore, it was shown that the decrease in strength must be taken into consideration in the preparation of WC-TaC-Co alloys containing a small amount of tantalum carbide.View full abstractDownload PDF (4282K) -
K. Tamura, T. Noda, O. Yamazaki1968 Volume 15 Issue 1 Pages 19-25
Published: January 25, 1968
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSMolybdänband wurde aus Pulver durch Pulverwalzen hergestellt. Die Duktilität der gesinterten Bänder and die mechanischen Eigenschaften der völlig behandelten Bänder sind mit den der Bänder verglichen, die auf übliche Weise durch Pressen-Durchstromsinterung erhalten waren. Das Band, das 1700°C 2 Stunden im Wasserstoffstrom gesintert war, war duktiler als Pressling, das in der festen Matritze verformt war and dieselbe gesinterte Dichte hat. Die Verformbarkeit des durch Pulverwalzen erhaltenen, dünnen Bandes war besser als die des auf übliche Weise hergestellten, dünnen. Der Unterschied der beiden Vorgänge für die Herstellung des dünnen Bandes, Pulverwalzvorgang und gewöhnlicher Press-Durchstromsinterungsvorgang, sind besprochen.View full abstractDownload PDF (3866K) -
K. Tamura, T. Noda, O. Yamazaki1968 Volume 15 Issue 1 Pages 26-30
Published: January 25, 1968
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIn der Absicht den Pulverwalzvorgang zu erörtern wurde zunächst die Abhängigkeit der Verbreitung der (321)-Interverenzlinie der Molybdänpulverpreßlinge von deren Dichte mittels Zählrohrgoniometers an den dünnen Preßlingen festgestellt, die mit einem einseitig wirkenden Preßwerkzeug hergestellt worden waren. Es wurde gefunden, daß es eine eindeutige Beziehung zwischen Preßdichte (order Preßdruck) and Integrallinienverbreitung gibt. Dabei war die Verbreitung wegen Pressens nach P. Scherrer als β=B-b (B: Integralbreite des Preßlings, b : Die des völlig geglühten Pulvers) ausgedrückt. Mit Hilfe dieser an tablettförmigen dünnen Preßlingen erhaltenen Ergebnisse gelang es, den Vorgang der Dichtezunahme and die spezifische Walzdrucksänderung im Walzspalte zu veranschaulichen. Der Greifwinkel, wo die tatsächliche Formgebung der Pulvermasse zum selbständigen Band stattfindet, ließ sich in drei Teilgebieten einteilen. Im ersten erfolgt die Verpackung der Pulver durch Gleitung. Im zweiten Bereich spielen plastische Verformung und Kaltschweißen wichtige Rolle und im dritten nimmt der Walzdruck vom höchsten Wert bis zum Null rasch ab. Der Unterschied zwischen dem Pulverwalzvorgang und dem üblichen Preßvorgang wurde besprochen.View full abstractDownload PDF (1397K)
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