Journal of Japan Foundry Engineering Society
Online ISSN : 2185-5374
Print ISSN : 1342-0429
ISSN-L : 1342-0429
Volume 77, Issue 5
Displaying 1-5 of 5 articles from this issue
Research Article
  • Osamu Kubo, Shyuzi Ishibashi, Takayuki Koie, Yasuhiro Matsubara, Katsu ...
    2005 Volume 77 Issue 5 Pages 293-300
    Published: May 25, 2005
    Released on J-STAGE: February 01, 2011
    JOURNAL FREE ACCESS
      Effect of chemical composition on the microstructure and characteristics of Ni-hard cast iron has been investigated in order to improve the wear resistance and other material properties by precipitation of hard M7C3 carbide and graphite.
       A small amount of graphite and M7C3 type carbide crystallize together in the cast iron of the composition of 2.6mass%C-7.0mass%Cr. The volume fraction of graphite increases with an increase in carbon content. Nickel has a strong effect on the transformation of matrix and the highest hardness is obtained in the cast iron containing 5.0mass%Ni in as-cast state, because of the transformation of austenite to martensite. Tensile strength decreases as carbon content gets over 2.6mass%. Heat crack length is the shortest in the cast iron of 2.6mass%C, and wear loss and amount of sticking decrease with increasing chromium and molybdenum contents. It was found that the optimum chemical composition of high chromium Ni-hard cast iron containing M7C3 type carbide and a small volume fractionofgraphiteis 2.6mass%C-2.5mass%Si-5.0mass%Ni-7.0mass%Cr-2.4mass%Mo, to improve the wear resistance remaining good mechanical properties of conventional Ni-hard cast iron.
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  • Yuzo Yokomizo, Nobuya Sasaguri, Kiyoshi Nanjo, Yasuhiro Matsubara
    2005 Volume 77 Issue 5 Pages 301-307
    Published: May 25, 2005
    Released on J-STAGE: February 01, 2011
    JOURNAL FREE ACCESS
      Influence of V content in multi-component white cast iron, which contains 5 mass% main alloying elements of Cr, Mo, W, each and 2 mass% of C and Co, on continuous cooling transformation behavior was investigated by varying the V content from 3 mass% to 9 mass%. The austenitizing temperatures used in this experiment were 1273 K and 1373 K.
      In the irons with up to 7 mass%V, both pearlite and bainite transformations appeared in CCT diagram, but in the iron with 9 mass%V, only transformation of ferrite precipitation was seen.
      The critical cooling rate of pearlite transformation (V C-P) decreased from 0.56 K/s to 0.11 K/s at 1273K austenitization and from 0.43 K/s to 0.06 K/s at 1373 K austenitization respectively, as the V content increased up to 7 mass%. The critical cooling rate of bainite transformation (V C-B) decreased with an increase in V content up to 4 mass%, but it increased over 4 mass%V.
      Though the Ms temperature did not change much between the irons with 3 mass%V and 4 mass%V, it gradually rose with an increase in the V content over 4 mass%, regardless of the austenitizing temperature. Mf temperature appeared first in the 5 mass%V iron at 1273K austenitization and in the 7 mass%V iron at 1373K austenitization, respectively, and then it rose corresponding to the increase of the V content.
      The highest macro-hardness of transformed specimen increased once and then gradually decreased as the V content increased. The V content at the maximum hardness was about 5 mass%.
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  • Kaoru Ohishi, Masayuki Mizumoto, Akio Kagawa
    2005 Volume 77 Issue 5 Pages 308-313
    Published: May 25, 2005
    Released on J-STAGE: February 01, 2011
    JOURNAL FREE ACCESS
      Recently, Rapid Prototyping has attracted considerable attention as a new manufacturing technology for metallic molds and parts. The optimum conditions to control the shape of castings produced by fused spinning deposition (FSD) method have been investigated for cylindrical and rectangular shaped hollow tube and solid specimens. In the present work, a double tube casting using two metallic materials, i.e., alloys having high melting point (Tm) and low melting point, was produced without welding. A cylindrical tube casting of Cu-20mass%Sn alloy (Tm = 1173 K) was prepared by sand mold casting, and set on the substrate of FSD apparatus. Then, Al-4mass%Cu alloy (Tm=923 K) was melted in a mullite tube with a small nozzle at the bottom. The molten aluminum alloy was cast on the outer surface of the copper alloy tube casting. It was found that the sufficient interface bonding between the aluminum alloy and copper alloy was obtained by using a refractory substrate with low thermal conductivity. Under a suitable condition, a part of the copper alloy casting was remelted and a reaction layer consisting of α phase, θ phase, δ phase and tin-rich phase was formed at the interface. When superheat of the molten aluminum alloy was increased, the reaction layer width was also increased. An excess heat capacity of the molten aluminum alloy leads to melting down and exfoliation of the aluminum alloy from the copper alloy casting by centrifugal force. A stable double tube casting was obtained when an optimal super heat of the molten aluminum alloy was chosen.
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  • Takeshi Suzuki, Sadato Hiratsuka, Hiroshi Horie, Shigeru Moriya, Mitsu ...
    2005 Volume 77 Issue 5 Pages 314-319
    Published: May 25, 2005
    Released on J-STAGE: February 01, 2011
    JOURNAL FREE ACCESS
      In this study, spheroidal graphite cast iron (FCD) with different Si content and stainless steel (SUS) were welded by the metal active gas (MAG) welding method using different types of Fe-Ni-Cr welding wires of different Ni and Cr equivalence. After welding, microstructure, Vickers hardness, quantitative and line analysis of alloying elements near the welding zone of each specimen were investigated. The results proved that a ledeburite layer is formed in the bonding interface between FCD and weld metals. Consequently Vickers hardness of the bonded zone was 800 to 900 HV. The widths of the ledeburite layer and heat affected zone (HAZ) was found to decrease with increasing Ni equivalent in welding wires and Si content in the FCD base metal respectively. Chromium carbide was found to precipitate in the grain boundary of weld metals using welding wire containing Cr
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