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Volume 68, Issue 10
Displaying 1-9 of 9 articles from this issue
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Research Article
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Takehiro Miyamoto, Hideki Narita, Hiroaki Kudoh1996 Volume 68 Issue 10 Pages 843-851
Published: October 25, 1996
Released on J-STAGE: February 01, 2011
JOURNAL FREE ACCESSThe measurement of volume change, including liquid contraction and subsequent dilation over the eutectic temperature range, was carried out on experimental castings of spheroidal graphite iron for various chemical compositions and pouring temperatures. The experimental casting was composed of a casting body heated small diameter cylindrical riser that magnifies the effects of contraction and dilation of the casting body, and sprue. The volume change of casting body was measured as the displacement of float on the upper surface of the riser. Experimental results were analyzed statistically, to determine the effects of the pouring temperature and C, Si content on the volume change of the casting. It was found that the pouring temperature and C content had significant effects while Si content had none. These results indicate that the chemical composition of spheroidal graphite iron is effective not only to produce high mechanical properties, but to prevent casting shrinkage.View full abstractDownload PDF (1185K) -
Akira Ikenaga, Yoshiyuki Goto, Yasuhiro Nitta, Makoto Kawamoto, Koujir ...1996 Volume 68 Issue 10 Pages 852-857
Published: October 25, 1996
Released on J-STAGE: February 01, 2011
JOURNAL FREE ACCESSTo examine the adequacy of densified Ni-Al intermetallic coatings as a surface modification process, the intermetallic compound by SHS reaction was coated on a spheroidal graphite cast iron substrate. The results obtained are that the void ratio in reaction layer after SHS reaction decreases with increasing pressure at cold pressing in the preparation of powder compact and pressure at hot pressing. Secondly the bondings between reaction layer and substrate are sufficiently achieved at all the conditions without compressing at hot pressing, but the conversion of SHS reaction layer to full densification is incomplete.View full abstractDownload PDF (981K) -
Toshiki Yoshida, Hideharu Nakano, Shinichiro Sengoku1996 Volume 68 Issue 10 Pages 858-864
Published: October 25, 1996
Released on J-STAGE: February 01, 2011
JOURNAL FREE ACCESSIn order to evaluate the chill forming tendency of molten spheroidal graphite cast iron, critical cooling rates for chill formation have been determined by measuring cooling curve and the corresponding chill area (area of eutectic cementite) of several samples with different chiller thickness. It is difficult to accurately measure the cooling rate of liquid during solidification using ordinary thermocouples because of poor response. When maximum cooling rate after solidification is used in place of cooling rate during solidification, a good relationship between the maximum cooling rate and chill area is obtained. With this method, the chill forming tendency of certain kinds of molten spheroidal graphite cast iron can be evaluated based on their different chill forming tendencies.View full abstractDownload PDF (1055K) -
Toshinori Kowata, Hiroshi Horie, Sadato Hiratsuka, Eiki Sato1996 Volume 68 Issue 10 Pages 865-869
Published: October 25, 1996
Released on J-STAGE: February 01, 2011
JOURNAL FREE ACCESSThe effects of the addition of the corresponding stoichiometric amount of rare earth elements (RE) in relation to the amount of sulfur (S) in cast iron melts with different carbon equivalent (CE) and the addition of inoculants such as Ca-Si and Fe-Si on the chilling tendencies and mechanical properties of flake graphite cast iron were investigated. The addition of the corresponding amount of about 0.2%RE, in relation to the amount of 0.08%S in the melt, was found to reduce the chilling tendency markedly. The effects of RE on the chilling tendency and tensile strength were found to improve the most in the low CE specimen and the least in the high CE specimen. When RE and Ca-Si as were added a post-inoculant to the melt with 3.4%CE, a tensile strength of 320MPa and Brinell hardness of 190 were obtained with a chill depth of 3mm.View full abstractDownload PDF (847K) -
Masayuki Ishikawa, Koichi Anzai, Eisuke Niyama1996 Volume 68 Issue 10 Pages 870-875
Published: October 25, 1996
Released on J-STAGE: February 01, 2011
JOURNAL FREE ACCESSDespite numerous studies on the fluidity of molten metals, little is known on fluidity in extremely thin sections such as 0.1mm or less. The objective of this study is to find factors dominating fluidity in extremely thin sections through droplet tests of Bi metals. Pure Bi was melted and dropped onto a gap of 0.03 to 0.1mm in width. The accuracy of the gap width was ensured by inserting gap gauges between the blocks of copper, steel, or quartz. The dropping height was changed from 30 to 120mm. The movement of the molten metal in the quartz mold was directly observed by a high speed camera. The relation between the gap width of mold and flow length was linear, and flow length increased with dropping height. Direct observation, showed that metal flow was slowed down by the resistance generated by viscosity and surface tension, and was stopped by solidification. The heat transfer coefficient was estimated to be about 45 to 60 kWm-2K-1.View full abstractDownload PDF (859K) -
Tsutomu Kurikuma, Yukuo Makimura, Masayuki Tada, Toshiro Kobayashi1996 Volume 68 Issue 10 Pages 876-882
Published: October 25, 1996
Released on J-STAGE: February 01, 2011
JOURNAL FREE ACCESSOne of the main advantages of casting irons is its high damping capacity. However, any attempt to improve damping capacity generally leads to a decrease in the tensile strength. In this paper, the effect of modified graphite morphology and matrix microstructure on the damping capacity has been studied in order to improve the damping capacity. An increase in the carbon equivalent promotes the precipitation of long and coarse graphite flakes. This improved the damping capacity, while the tensile strength decreased. An austempering treatment, which produced ausferritic matrix structure, was found to improve the damping capacity without sacrificing the tensile strength.View full abstractDownload PDF (996K) -
Katsuya Ikawa1996 Volume 68 Issue 10 Pages 883-890
Published: October 25, 1996
Released on J-STAGE: February 01, 2011
JOURNAL FREE ACCESSThe concept of “Reifegrad” is widely used for estimating the quality of gray cast iron. According to this concept, quality is expressed by the comparison of the actual tensile strength with the standard tensile strength of the same carbon equivalent. The tensile properties of ductile cast iron are basically governed by matrix structure and also affected by nodularity of graphite, existence of microporosity, etc. Because the Brinell hardness properly expresses the state of matrix structure, the comparison of the actual tensile properties and standard properties for the same Brinell hardness is considered to be “Reifegrad” of ductile cast iron. Estimation of the quality of ductile cast iron was attempted in this way in several case were made trial.View full abstractDownload PDF (984K) -
Nobuaki Ohnishi, Tetsuya Takaai, Yoshihiro Nakayama, Masahiro Ohmori1996 Volume 68 Issue 10 Pages 891-897
Published: October 25, 1996
Released on J-STAGE: February 01, 2011
JOURNAL FREE ACCESSThe effects of solidification structure on the fatigue life and fatigue crack growth behavior in AC4CH aluminum casting alloy were experimentally investigated in view of the size of the dendrite arm spacing, morphology and size of eutectic silicon particles. Fatigue life and fatigue crack growth tests were performed under the controlled load condition using smooth type and CT type specimens. The specimens were solution-treated at a relatively higher temperature, 843K. The results obtained are summarized as follows ; (1) The refining of the dendritic structure and eutectic silicon particles improved the fatigue life, suggesting that the casting defects exerted substantial influence on fatigue life. (2) The fatigue crack growth rate was decreased with the refining of the dendritic structure and eutectic silicon particles. (3) The high temperature solution treatment slightly incresed the fatigue crack growth rate.View full abstractDownload PDF (1023K)
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Hisao Hirono, Fumio Yamaguchi, Tsuyoshi Kokusho1996 Volume 68 Issue 10 Pages 903-907
Published: October 25, 1996
Released on J-STAGE: December 18, 2014
JOURNAL FREE ACCESSIn recent years, the valve train of automobile engine has been actively developed to obtain superior intake and exhaust efficency and thermal efficency at same time. Therefore, the working conditions of cameshafts have become more severe. There is increasing demand for camshaft materials which have higher wear resistance. Remelting process only at the friction area of cam face with highly cocentrated prasma arc energy and adding alloying elements to the melt pool will create a new alloying layer with high wear resistance. This paper describes the development of plasma surface modification technique, the feature of this process and the characteristics of the alloyed layer etc.View full abstractDownload PDF (1992K)
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