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Volume 56, Issue 6
Displaying 1-7 of 7 articles from this issue
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RESEARCH REPORT
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Keizo SAKURAI, Takeshi SAWAI, Katsushige ADACHI2006 Volume 56 Issue 6 Pages 301-306
Published: 2006
Released on J-STAGE: August 15, 2006
JOURNAL FREE ACCESSMachining processes such as drilling and tapping are necessary before MMC can be used as a machine parts. However, since MMC contains ultra-hard particles and short fibers machining is difficult due to the severe tool wear in cutting operations. Therefore in this study, an efficient machining method of the female screw which is essential for fastening machine parts is examined by subjecting the work piece material to plastic deformation and an attempt is made to tap MMC with fluteless tap that forms the female screw. Tapping tests on Al–15%SiC alloy were carried out using two types of fluteless taps HSS and TiN coated fluteless taps. The following conclusion can be drawn after examining results of the processing characteristics. The friction coefficient of the TiN coated tap is less than that of the HSS tap, due to the excellent wear resistance of the TiN coated tap processing resistance is small resulting in a 3.8 fold increase in tool life. The plastic flow evident during the formation of threads is small. As a result, with TiN coated tap, the work hardening of the thread surface is 35% lower than with HSS tap. It is evident that thread formation is efficiently performed.View full abstractDownload PDF (1411K) -
Tomo-o TANAKA, Masaya ITO, Toshio NARITA2006 Volume 56 Issue 6 Pages 307-312
Published: 2006
Released on J-STAGE: August 15, 2006
JOURNAL FREE ACCESSThe conditions of a solution treatment and a water quenching and the structure of a buffer layer for thermal stress were investigated in the joining of A2024 to ZrO2 using Al–13.6Cu–2.4Si–50Zn brazing filler metal. The prevention of the ceramic crack by heat shock and aging treatment became possible for the joining of A2024 to ZrO2 by the partial water quenching after solution treatment. The hardness of A2024 aluminum alloy under the joining interface reached to 72HRB, which was converted into 450 MPa of tensile strength of the alloy. A5052 and A1050 buffer layers were inserted between ZrO2 and A2024 in order to decrease the thermal stress, so that the joint strength was obtained about 200 MPa after the aging. The joint strength of the A2024/Si3N4 joint was obtained about 180 MPa. These A2024/ceramic joints had enough joint strength and enough tensile strength of A2024 alloy part that are applicable for various structural components.View full abstractDownload PDF (1191K) -
Minoru ISHIGURO, Seijiro MAKI, Ken-ichiro MORI2006 Volume 56 Issue 6 Pages 313-316
Published: 2006
Released on J-STAGE: August 15, 2006
JOURNAL FREE ACCESSA treatment consisting of resistance heat treatment and artificial aging was developed to improve the product strength and press formability of Al–Mg–Si alloy sheets having paint bake hardenability used for automobile body panels. In this treatment, the sheets are re-solution heat-treated by resistance heating and water quenching just before the press forming. The formed sheets are artificially aged just after the press forming to increase the product strength. In the experiment, Al–0.60%Si–0.74%Mg (A6061) alloy sheets were chosen. The solution heat treatment of the sheets was sufficiently accomplished by the rapid resistance heat treatment, and the press formability of the sheets was improved. The hardness of formed products is increased by the artificial aging and paint bake hardening. It was found that the present heat treatment is effective in improving the product strength and press formability of the Al–Mg–Si alloy sheets having the paint bake hardenability.View full abstractDownload PDF (404K) -
Koji TANAKA, Masaki KUMAGAI, Hideo YOSHIDA2006 Volume 56 Issue 6 Pages 317-322
Published: 2006
Released on J-STAGE: August 15, 2006
JOURNAL FREE ACCESSFriction stir spot welding (FSSW) was applied to dissimilar lap joint between aluminum alloy sheet and mild steel sheet without formation of brittle intermetallic compound at the weld interface. A sufficient strength of the dissimilar joint was obtained by stirring aluminum alloy near the interface without inserting a welding tool to steel surface from the aluminum alloy side. Consequently, joint strength of FSSW was higher than that of resistance spot welds, and the all of FSSW joints showed a plug fracture through aluminum alloy parent sheet. Moreover, it was suggested that joint strength was related to area of stir zone at the weld interface. An oxide film was observed partially in the stir zone by sweeping up from the interface. No brittle intermetallic compound was observed at the weld interface. But only the thin amorphous layer of several nm in thickness including oxygen was found at the weld interface.View full abstractDownload PDF (3042K) -
Toshihiko KUWABARA, Masafumi UMEMURA, Kengo YOSHIDA, Mitsutoshi KURODA ...2006 Volume 56 Issue 6 Pages 323-328
Published: 2006
Released on J-STAGE: August 15, 2006
JOURNAL FREE ACCESSForming Limit Curves (FLCs) of 5000 series aluminum alloys with different Mg contents, 2.5 and 5.5 mass%, are experimentally determined in detail using the Marciniak test. The forming limit strains of the Al–Mg 5.5% alloy are larger than those of the Al–Mg 2.5% alloy from uniaxial tension to near plane-strain tension regions, whereas the order of formability is reversed in the biaxial stretching region. To evaluate the work-hardening behavior of the test materials under biaxial tension and to determine appropriate anisotropic yield functions, biaxial tensile tests of the test materials are carried out using cruciform specimens. Moreover, forming limit strains of the test materials under proportional loading are calculated using the Marciniak-Kuczyński approach based on a phenomenological plasticity model with non-normality effects [Kuroda and Tvergaard, 2001, J. Mech. Phys. Solids, 49, pp. 1239–1263]. The validity of the phenomenological plasticity analysis is discussed by comparing the observed FLCs with calculated ones.View full abstractDownload PDF (755K) -
Takashi IIZUKA, Nobuo HATANAKA, Norio TAKAKURA2006 Volume 56 Issue 6 Pages 329-334
Published: 2006
Released on J-STAGE: August 15, 2006
JOURNAL FREE ACCESSIn the bulging, the material existing at the flange portion is not drawn into the die opening, and so the periphery of a metal sheet blank does not change. This feature of the bulging is advantageous to producing cups with wide flange. On the other hand, there is a weak point that it is difficult to make cups with large height by the bulging. This is because the thickness of metal sheet at punch shoulder decreases locally and it results in a quick breakage at this portion. At this point, the thickness of the sheet at the other portions, e.g. punch head and sidewall, has been little decreased. Therefore, if the thickness of the sheet metal could be decreased more uniformly in the bulging, producing shells with wide flange and large height becomes possible. In this study, in order to get higher cups with wide flange, a new process of bulging combined with ironing was tried. In the new process, a hemispherical rubber punch and metal counter punch were used for thinning material at punch head. And the material at sidewall of the stretched cup was thinned by a following ironing process. Variations of thickness strain distribution by each process were measured and the effectiveness of the process was clarified. Finally, it was possible to make a stretched cup twice as high as that made by conventional bulging.View full abstractDownload PDF (1737K)
REVIEW
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Yoji AWANO2006 Volume 56 Issue 6 Pages 335-342
Published: 2006
Released on J-STAGE: September 30, 2006
JOURNAL FREE ACCESSDownload PDF (2248K)
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