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Volume 33, Issue 11
Displaying 1-9 of 9 articles from this issue
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Takeo OKI1983 Volume 33 Issue 11 Pages 647-648
Published: November 30, 1983
Released on J-STAGE: July 23, 2008
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Eiichiro SATO, Tsuneo SAGA, Shuji NAGAI1983 Volume 33 Issue 11 Pages 649-654
Published: November 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSMachinability of Al-Si eutectic alloys containing small amount of additional element Na or Sr was studied by two dimensional and three dimensional cutting tests. In the range such as the good effect of modification is recognized, it has been confirmed that the addition of Na or Sr has a marvellous effect to the machinability (Cutting resistance, tool wear, cutting temperature, and surface roughness etc, ) of these alloys. It was especially cleared that the increase in shear angle has a favourable influence upon tool wear and surface roughness. But, it seems that a new question is raised from a standpoint of chip treatment.View full abstractDownload PDF (1254K) -
Katsuhisa NAGAYAMA, Katsusaburo TOYODA, Yoshishige TSUMURA1983 Volume 33 Issue 11 Pages 655-659
Published: November 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSMagnesium-containing aluminum alloy is electrolyzed as anode using a tungsten rod as cathode and a ceramic fiber cylinder permeated by molten chlorides as electrolyte and diaphragm at 720°C. Demagging current effciency was tested in the range of current density from 0.18 to 0.71A/cm2. Effect of magnesium chloride content of the electrolyte on demagging efficiency was also studied in the range 040wt.%in NaCl 50wt.%-KCl 50wt.% mixtures and proved to have no relation. Magnesium content of the aluminum alloy decreased to less than 0.1% from initial content of 1.0%. Demagging current effciency falls as current density increases as the result of partial chlorination of aluminum on the surface of anode.View full abstractDownload PDF (728K) -
Fumio NOGUCHI, Takashi NAKAMURA, Yasuaki UEDA, Tsutomu YANAGASE1983 Volume 33 Issue 11 Pages 660-669
Published: November 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSIt is of great importance to understand the mechanism and the rate of Al2O3 dissolution into cryolite melt. This study is mainly concerned with the direct observation of melt through microscope and mesuring the dissolution rate of various type of Al2O3 by using the hot-thermo couple technige. The experimental results indicated that the dissolution pattern of Al2O3 in cryolite melt is divided into three types due to difference in crystal form irrespective of shape and size of Al2O3 and mode of press. The dissolution pattern of θ, δ and κ-alumina obtained by calcination of boehmite and gibbsite at low temperature showed type I and these dissolution proceeded rapidly from top part of Al2O3 into melt. On the other hand, the dissolution rate of Al2O3 obtained from gibbsite was very small and showed type II or III. Such classification was dependent upon the content of α-alumina expressed by relative X-ray intensity of α-alumina in the calcined products. The effect of addition of other fluorides to the cryolite melt upon the dissolution rate has been also investigated. The addition of NaF was found effective to increase the dissolution rate of alumina.View full abstractDownload PDF (2627K) -
Shinya KOMATSU, Hideyuki AKAGI, Takashi SUGIMOTO, Kiyoshi KAMEI1983 Volume 33 Issue 11 Pages 670-675
Published: November 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSUnitended aging time after room temperature (R. T.) rolling was shortened up to 5s by reciprocal rolling of letter "U" shaped specimen using hand-droven reversing mill. Size factor after rolling was estimated assuming same resistivity for first and second solution treatment. Application of this method to several Al-Zn-Mg alloys makes observable the decrease of specific resistivity by the R. T. rolling, similarly as that by tensile deformation at 78K. The maximum decrement of resistivity ranges 4.2-13% of the resistivity increment by aging before the deformation. Generally, the resistivity decrement by deformation is large in high concentration alloys and becomes larger in the alloy of higher Zn concentration. Aging after deformation is accelerated in initial stage with degree of deformation by both R. T. rolling and 78K elongation, but is decelerated rapidly in later stage of aging.View full abstractDownload PDF (838K) -
Yoshio HASEGAWA, Shinsaku HANASAKI, Ji-Bok SONG1983 Volume 33 Issue 11 Pages 676-682
Published: November 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe efficancy of the grinding fluid in prevention of the loading was studied for following workmaterials, i. e. commercial pure aluminum and aluminum alloys of AC2A-F, AC3A-F and ACBA-T6, which cause the loading in dry grinding. Coating of a small quantity of lubricative oil on the workpiece surface is considerably effective in prevention of occurrence and growth of the loading. Application of lubricative oil with the nozzle being held about 0.3mm distant from the grinding wheel is very useful for prevention of occurrence and growth of the loading, and a good surface is obtained for AC2A-F, AC3A-F and ACBA-T6. The cooling action of the grinding fluid is little useful for prevention of the loading. The washing action of fluid jet is not always useful for prevention of the loading. Its effectiveness seems to depend on the adhesion strength of chips to the cutting edges of abrasive grains.View full abstractDownload PDF (1724K) -
Hisashi SUZUKI, Motohiro KANNO, Hiroshi SAITOH1983 Volume 33 Issue 11 Pages 683-688
Published: November 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe hot-rolled 7075 alloy specimen was solution-treated at 470°C, quenched, overaged at temperatures ranging from 200 to 400°C, cold-rolled and finally solution-treated at 470°C for different times. Recrystallized grain structures were examined by using optical, scanning and transmission electron microscopes.
It was confirmed that overaging at 400°C was most effective for getting fine recrystallized grains. This is due to the fact that coarseη precipitates larger than about 1μm, formed during overaging, were apt to act as nucleation sites for new grains in the deformed matrix during final heat-treatment. The cold-workability was improved, when the overaged specimen was successively aged at a lower temperature. In the specimen subjected to high cold-reduction, finer recrystallized grain structure was brought about.View full abstractDownload PDF (2090K) -
Iwao IZUMI, Takashi AZEGAMI1983 Volume 33 Issue 11 Pages 689-701
Published: November 30, 1983
Released on J-STAGE: July 23, 2008
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1983 Volume 33 Issue 11 Pages e3
Published: 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (99K)
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