All issues
Volume 43, Issue 11
Displaying 1-14 of 14 articles from this issue
- |<
- <
- 1
- >
- >|
-
Sanji KITAOKA1993 Volume 43 Issue 11 Pages 567-573
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (904K) -
Yo KOJIMA1993 Volume 43 Issue 11 Pages 574-580
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (736K) -
Toshiro KOBAYASHI, Mitsuo NIINOMI, Michimasa YAMAOKA, Yuichi SHIMOMURA ...1993 Volume 43 Issue 11 Pages 581-587
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSEffects of Fe content and Ca addition on the mechanical properties and toughness in several types of casting alloys, AC4C-T6, AC2B-T6 and AC4D-T6 are investigated. The modification of eutectic Si is successfully achieved by 40ppm Ca addition in AC4C-T6 and AC4D-T6 alloys. The mechanical properties and toughness are made worth with increasing Fe content especially when Ca is not added: the elongation, Charpy absorbed energy and dynamic fracture toughness of the alloys are improved with the addition of Ca. The 0.2% proof stress and tensile strength decrease by adding Ca in some alloys. The decreasing ratio of proof stress and tensile strength are, however, much smaller than the increasing ratio of toughness when Ca is added to the alloys.View full abstractDownload PDF (815K) -
Yutaka WADA, Hiroyoshi KUROSAWA, Mitsuaki FURUI, Yo KOJIMA, Mamoru MAT ...1993 Volume 43 Issue 11 Pages 588-593
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSAluminum alloy ingots with various rectangular sections were fabricated by controlling the magnetic field which was changed by the inductance of external coil. The intensity of magnetic field which was increased greatly near the corner of rectangular electromagnetic coil was locally restrained by the corner screen. The effect of corner screen on the magnetic field distribution was clarified by the numerical analysis. The fabricated ingot had the lustered and smooth surface which was a typical feature for electromagnetic casting. The cross section of ingot resembled the inside shape of electromagnetic coil except for the ingot corner. The mechanical properties of fabricated ingot had little difference from DC cast.View full abstractDownload PDF (962K) -
Kinya OHARA, Osamu WAKASAKI, Tomoya OHZONO1993 Volume 43 Issue 11 Pages 594-599
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSEffects of Li content and grain-refiner addition on the hot-tearing characteristics of Al-Li binary word alloys (0-3mass%) and the commercial Al-Li alloys (2090, 2091, 8090 and 2219+1.5mass%Li) were investigated by using hindered type hot-tearing test (I-beam test). High strength alloys, 2024 and 7075 were also investigated to compare with the commercial Al-Li alloys. In Al-Li binary alloys, the tearing tendency was decreased with increasing Li content, but was not improved by the grain-refiner addition, and the efficiency of grain refinement was less than in the pure aluminum. In the commercial Al-Li alloys, the tearing tendency was same as 2024 and 7075 alloys in the case of no additioning grain-refiner, but was not so improved by the grain-refiner addition, while in 2024 and 7075 alloys remarkably improved, and the efficiency of grain refinement was less than in 2024 and 7075 alloys.View full abstractDownload PDF (590K) -
Kinya OHARA, Osamu WAKASAKI, Masayasu TOYOSHIMA, Tomoya OHZONO1993 Volume 43 Issue 11 Pages 600-605
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe prevention of hot-tearing in the commercial Al-Li alloys ingots (150mm×350mm) produced by DC casting was studied. Crack started at the caved part of ingot surface which was contaminated by oxide. The molten metal surface was ventilated by Ar gas to inhibit the generation and contamination of oxide. The stress by solidification shrinkage was reduced by decreasing casting speed, because the faster casting speed caused larger shrinkage. But the pouring temperature and coolant flow rate had no influence. No crack was detected in 2024 alloy. Shrinkage of Al-Li alloys was larger than 2024 alloy, and that was the one of the reasons why Al-Li alloy easily cracked. The faster casting speed causes the deeper sump.View full abstractDownload PDF (1829K) -
Toshimasa MOROOKA, Eiji YUASA, Masao HARA, Daisuke KOBAYASHI1993 Volume 43 Issue 11 Pages 606-611
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe atomized Al-12 and 17mass%Si alloy powders were precompacted in a cylindrical die and heated at eutectic temperature for various periods. The volume fraction of solid phase in the slurry was controlled by heating period. When the small quantities of liquid phase was formed, the density reaches to over 99% of the calculated value by applied compressive stress of low level. However, if the volume fraction of solid phase decreases to 50%, the large voids form in the center of products. The size of silicon particles crystallized from the liquid phase becomes large with decreasing of the volume fraction of solid, but this coarsening of silicon particles is suppressed by pressing continuously before the generation of liquid phase. The bonding strength between the powder particles increases by the continuous pressing.View full abstractDownload PDF (1188K) -
Masaaki KOGA, Tetsuya TAKAAI, Yoshihiro NAKAYAMA, Nobuaki OHNISHI, Yas ...1993 Volume 43 Issue 11 Pages 612-617
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSAge hardening process of the AC4CH casting alloy solution treated at 843K was investigated mainly in view of aging temperatures. About 5 to 10% improvement of the tensile properties were obtained for the aging treatment at 418K for longer aging time as compared with those of the alloys heat treated with the conventional conditions. The percent elongation to the fracture and the absorbed energy, however, were not effectively improved. Reasonable correspondence between 0.2% proof stress and the specific resistance ratio were obtained. The proof stress was higher for the specimens aged at lower temperatures, although the resistance ratios were identical. The calculated m values of the Johnson-Mehl's equation for the precipitating particles were different for higher and lower temperatures, suggesting that the growth behavior of the particles was elassified into two types.View full abstractDownload PDF (844K) -
Kaneo MIZUNO, Erqing FAN, Sigeo FURUTANI, Shigeaki YOKOTA, Tatsuichi F ...1993 Volume 43 Issue 11 Pages 618-624
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSA study has been carried out on the cooling rate, dendrite arm spacing and mechanical strength for AC4B cylindrical aluminum alloy castings. The cooling rate of castings becomes smaller with increasing the sectional area and mass of castings because the diameter of cores becomes smaller. The dendrite arm spacing and mechanical strength also change with the cooling rate. The solidification time of the AC4B cylindrical aluminum alloy castings is expressed by a function of the casting's modulus. The calculated n value is 1.5, which is identical with the experimentally obtained n value. Therefore, an equation of tf=K(V/S)1.5 is obtained for the solidification time of castings. Linear relationships on the logarithmic graph are obtained between the casting's modulus (M) and the average cooling rate (VS) or the dendrite arm spacing (DS). Assuming that the mechanical strength is closely related to the reciprocal of the casting's modulus, the appropriate equation is obtained. Furthermore, equations describing the relationships between the colling rate of the AC4B cylindrical aluminum alloy casings and mechanical strength or the dendrite arm spacing are obtained as follows:
VS=(V/S)-1.75, DS=B(V/S)0.5
σB=K1(V/S)-n, HB=K2(V/S)-n
σB=B1VSn, HB=B2VSn, DS=CVSn.View full abstractDownload PDF (651K) -
Shogo MOCHIZUKI, Kyoji SATO, Hidetoshi KAWADA1993 Volume 43 Issue 11 Pages 625-629
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSChlorine is considered influential in the corrosion of magnesium alloys, however, there are few reports which describe the effects of chlorine quantitatively. In this report the relationship between chlorine content and corrosion rate of magnesium alloys was made clear. Firstly, the discussion was made how to obtain HPDC magnesium samples containing chlorine. The samples were obtained by adding powder flux containing MgCl2 in a ladle before injection. Corrosion rate was measured by means of Salt Spray Test. The relationship is formulated in the following equation: Corrosion rate (mg•dm-2•h-1)=1.04+1.92× chlorine content (%) Humid Box Test showed similar results.View full abstractDownload PDF (786K) -
Seiji SAIKAWA, Shigeru SUGIOKA, Kiyoshi NAKAI, Yasuo SUGIURA, Akihiko ...1993 Volume 43 Issue 11 Pages 630-635
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe suitability of ceramic molds used for producing Al-Li alloy investment castings was investigated. Molds were made by the lostwax process. Visual inspections of the as-cast casting surfaces indicated that there were large gas bubble defects due to melt-mold interaction when those were cast into conventional molds consisted of SiO2•ZrO2 filler. X-ray microanalysis showed that the main product of that interaction was Li2CO3. However, good quality Al-Li castings were obtained when cast into ceramic molds which consist of MgO filler, TiO2 binder and Al2O3 stucco under an argon atmosphere. The ultimate tensile strength ceramic mold castings of Al-2.5%Li-2%Mg-0.15%Zr-0.12%Ti alloy was lower by around 85% than that of the metal mold castings, while its elongation was 5%.View full abstractDownload PDF (1102K) -
Eisuke NIYAMA1993 Volume 43 Issue 11 Pages 636-642
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (925K) -
Kazunori KOBAYASHI1993 Volume 43 Issue 11 Pages 643-644
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (217K) -
Makoto SUGAMATA1993 Volume 43 Issue 11 Pages 645-646
Published: November 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (250K)
- |<
- <
- 1
- >
- >|