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Volume 33, Issue 4
Displaying 1-8 of 8 articles from this issue
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Shiro SATO1983 Volume 33 Issue 4 Pages 177-178
Published: April 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (328K) -
Akihiko KAMIO, Hiroyasu TEZUKA, Shinji KUMAI, Tsuneo TAKAHASHI1983 Volume 33 Issue 4 Pages 179-187
Published: April 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe dependence of L2 phase particle distribution in the matrix of monotectic alloys on such solidification parameters as temperature gradient, growth rate and cooling rate was examined. Al-10wt%Pb and Al-3.4 to 30wt%Bi alloys were solidified unidirectionally in an insulating mold placed on a copper chill and non-directionally in graphite, copper and water-cooled copper molds. The alloys containing a liquid miscibility gap solidify accompanying heavy gravity segregation. This segregation is caused by coarsening of L2 phase droplets and their migration during cooling in the miscibility gap. Casting monotectic alloys containing Pb up to 10wt% and Bi up to 20wt% in a copper mold ensures fine and homogeneous dispersion of L2 phase particles.View full abstractDownload PDF (2193K) -
Hiroshi OHUCHI1983 Volume 33 Issue 4 Pages 188-194
Published: April 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAl-20%Si alloy castings 23mm in diameter and 23mm in height containing Cu up to 3% and Mg up to 5% were subjected to 500°C for 20min and quenching into iced water. When the castings containing Mg are subjected to thermal shock, the occurrence of a number of micro-cracks causes porosities in the castings and expansion of them. The castings containing Cu less than 0.5% considerably deform and heavily fissure on their surfaces resulting in a slight decrease in apparrent specific gravity. The castings containing Cu 1% or more behave similarly as the Mg-containing ones. The alloy containing such heat treatable alloying elements as Cu and Mg are poor in resistance to thermal shock.View full abstractDownload PDF (1232K) -
Teruo OHASHI, Kenji KOBAYASHI, Kenji NOZUE1983 Volume 33 Issue 4 Pages 195-203
Published: April 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSA weldability test on AC3A (Al-12.5%Si) and AC7B (Al-10%Mg) castings was carried out using 4043 alloy of a filler metal. The weld heat input has little effect on the Na-modified eutectiic structure and impact strength of AC3A. The weld metal having refined eutectic and α-dendritic structures has impact strength twice as high as the modified base metals. The weld joint of AC7B-F castings is remarkably brittle. Toe-cracking often occurs at a heavy heat input. The impact strength of AC7B-T4 weld joints drops in the heat affected zone where grain boundary precipitation occurs considerably. Such a decrease in ductility is attributed not to the precipitation but to GP zone formation accelerated by cyclic heat input.View full abstractDownload PDF (3914K) -
Keizo NANBA1983 Volume 33 Issue 4 Pages 204-211
Published: April 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe optimum forming condition for BA11 welded tubes is inadaptable to 5083 tubes. An effect of formability on the welding cycle to which the faying edges are subjected was examined on 5083 alloy in comarison with that on BA11 alloy. The skelp edge of 5083 alloy forms into a V-groove not into a square groove. This fact cases uniform heating and upsetting of the edge. A trial was made to form the faying edge into a square groove. The effective precaution includes to form the skelp having a smaller radius, and ensures stable weld without misaligment and offset. The edge preparation is an important factor governing the weld quality. Welding conditions such as power imput and girth reduction were also determined.View full abstractDownload PDF (1849K) -
Mutsuo OHTA, Hiroshi YAMADA, Teruto KANADANI, Akira SAKAKIBARA, Masuo ...1983 Volume 33 Issue 4 Pages 212-220
Published: April 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAge hardening in Al-10 and 12 wt%Zn alloys at room temperature was studied with a careful attention to the position of impression in hardness tests. The specimens 1.0mm in thickness quenched at temperatures from 300°C to 550°C and aged have a softened surface layer. This soft layer is considerably thick near the grain boundary in the specimens quenched at temperatures below 400°C. The specimens 0.2 and 0.4mm in thickness have nearly the same hardness both in the surface layer and interior, although they have a softened surface layer near the grain boundary when quenched at temperatures below 400°C. Hardening proceeds at a slower rate in the soft region than in the hard region and ceases incompletely under certain conditions. These facts and transmission electron micrographs are discussed on the basis of a decrease in vacancies near the sinks such as surface and grain boundary.View full abstractDownload PDF (2120K) -
Mikio KANEHARA1983 Volume 33 Issue 4 Pages 221-229
Published: April 30, 1983
Released on J-STAGE: July 23, 2008
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Takeshi MURAKAMI, Tsuneo TAKAHASHI1983 Volume 33 Issue 4 Pages 230-239
Published: April 30, 1983
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (1557K)
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