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Volume 31, Issue 6
Displaying 1-10 of 10 articles from this issue
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Mustu OHTA1981 Volume 31 Issue 6 Pages 369-370
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (301K) -
Koichi YAMADA1981 Volume 31 Issue 6 Pages 371-377
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSEffects of carbon compounds on crystallization of aluminum hydroxide from sodium aluminate solution and oxidation decomposition of organic compounds in the Bayer process were studied. Both organic and inorganic compounds in the liquor decrease the precipitation yield of aluminum hydroxide. Sodium oxalate coprecipitated simultaneously with the seed aluminum hydroxide inhibits agglomeration of particles crystallizing in the solution. Conversion yields from the carbon compounds to carbonate and oxalate by oxidation in the process are 30 and 3 to 20% respectively. Goethite plays an important role for the oxidation during digestion step of bauxite. Cu++ in the liquor has a catalytic effect on the oxidation from the carbon compounds to carbonate.View full abstractDownload PDF (1067K) -
Shigeo ZAIMA, Yuzo TAKATSUJI, Hiroki OKUSHIMA, Shigeru YAMADA1981 Volume 31 Issue 6 Pages 378-385
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSElectron probe microanalyses were carried out on the wear progression of high speed steel tools. Crater and flank wear takes place in wet cutting of 7075-T6 in the same manner as in dry cutting. In wet cutting of AC3A, grooving wear occurs on the side and end cutting edges. The wear proceeds on such a way that small particles of high scratch hardness such as primary silicon particles clash into the tool face and scratch the matrix around tungsten carbide particles in the tool, and the carbide particles rise and fall off. The flowing form of chips and the manner of chip clashing to the tool lead to different manners of wear depending on the work material, tool material and cutting condition.View full abstractDownload PDF (2627K) -
Kenji HIGASHI, Tadakazu OHNISHI, Yoshizo NAKATANI, Kunio OKABAYASHI1981 Volume 31 Issue 6 Pages 386-392
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSTensile loading tests were carried out on pre-cracked Al-8%Mg alloy specimens hydrogen charged or stress corrosion tested. Fractography and measurements of crack propagation and stretched zone widths show formation of pre-existing embrittled zone ahead of stress corrosion crackes. This zone disappears when the specimen stress corrosion tested is aged at room temperature. The pre-existing embrittled zone is a sequence of hydrogen embrittlement from the facts that formation and disappearance of the zone are similar to those of embrittled fracture of hydrogen charged specimen and that hydrogen permeates into the specimen during stress corrosion testing.View full abstractDownload PDF (2065K) -
Hiroshi ISHIMARU, Junichi KANEKO, Makoto SUGAMATA1981 Volume 31 Issue 6 Pages 393-400
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSTernary magnesium alloys containing aluminum 1.2 to 11% and zinc 0.8 to 12.5% were cast into permanent molds under atmospheric pressure and 2000kgf/cm2 to examine composition effects. The nonequilibrium solidification temperature range widens with increasing Al+Zn content due to the eutectic reaction with a ternary compound. The composition range for occurrence of hot tearing was determined. AZ91, AZ88 and ZA128 are unsusceptible to hot tearing. Among the gravity casings AZ91 and AZ63 are the highest in tensile strength, elongation and impact value. The density increases by 1% at most by high pressure casting. The relative increases in tensile strength and elongation by high pressure casting are larger for the alloys containing higher Al+Zn. High pressure castings of AZ88, ZA101 and ZA124 have tensile strength higher than those of AZ91. Relative increases in mechanical properties by high pressure casting are discussed in relation to the castability of the alloys.View full abstractDownload PDF (1190K) -
Shiro SATO, Noboru OKOSHI1981 Volume 31 Issue 6 Pages 401-409
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSWrought alloys H112 and T4 treated have the proof stress ratio σ0.2/σB little greater than 0.7 and ones T6 treated have the ratio little smaller than 0.9. A linear relationship is found between the proof stress ratio and the n-value. The elongation determined from the strain distribution in the specimen considerably agrees with the uniform elongation calculated by Barba's law, but the value measured from the change of section-area of the specimen disagrees. Brinell hardness rises with increase of the indenting load and attains the maximum at about d/D=0.4 (d: impression diameter, D: ball diameter). HB of the alloys of high n-value remains constant with increase of the load, but HB of the alloy having low n-value lowers with increase of the load. The test loads 1000kg and 1500kg are recommended rather than 500kg respectively for most of aluminum alloys and for ones having HB more than 80 to obtain the maximum hardness.View full abstractDownload PDF (1016K) -
Tsuneo SAGA, Shigeru IKEDA1981 Volume 31 Issue 6 Pages 410-414
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSEffects of extracting direction of the specimen on various mechanical properties of A5083P-0 alloy plates 100mm in thickness were studied. Tension, fatigue, impact and torsion test values depend on the extracting direction. The specimens taken in the direction of plate thickness have remarkably lower test values than those taken in the rolling direction. The fact is attributed to the shape of crystals and intermetallic compounds perpendicular to the loading direction. The crystallographic orientation is a secondary factor.View full abstractDownload PDF (939K) -
Tetsuichi MOTEGI, Atsumi OHNO1981 Volume 31 Issue 6 Pages 415-421
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSMolten aluminum containing a grain refiner was cast into a metallic mold. The solidified castings have an equiaxed structure. When the castings are then remelted and unidirectionally solidified from the bottom, three types of structures, only columnar, equiaxed at the bottom and top, and entirely equiaxed crystals are formed. If such ingots are remelted again and cast into the metallic mold, the solidified structure is of equiaxed. Primary particles of TiAl3 in Al-Ti master alloy promote formation of equiaxed crystals only when they remain in the melt during pouring as fine particles. Dissolved titanium in the melt always acts as a grain refiner, if the melt is disturbed sufficiently to ensure separation of the necked shape crystals from the mold wall.View full abstractDownload PDF (2489K) -
Ken TOHMA, Yo TAKEUCHI1981 Volume 31 Issue 6 Pages 422-430
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
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Ryo HORIUCHI1981 Volume 31 Issue 6 Pages 431-444
Published: June 30, 1981
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (2002K)
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