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60 巻, 11 号
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研究論文
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柴田 文男, 内田 幸彦1988 年 60 巻 11 号 p. 666-671
発行日: 1988/11/25
公開日: 2011/09/08
ジャーナル フリーElectron beam welding of 6kW class was applied to I-type butt welding of 18mm thick as-cast plates of spheroidal graphite cast iron(FCD45 and FCD50) without preheating, using 0.5mm plates of austenitic stainless steel(SUS304) and pure nickel as insert metals. Relations between mechanical properties of as-welded joints porosity existence ratio or area ratio in fracture surfaces were examined. The mean hardness of the fusion zone with pure nickel insert metal was Hv250 to 350, being higher than that with SUS304, Hv140. The width of the hardened zone was wider with nickel insert metal than with SUS304. When graphite is present in the fusion zone, martensite is formed around its peripheries, causing a remarkable increase in hardness. The tensile strength of the welded joints was higher with SUS304 insert metal than with pure nickel, reflecting the difference in the amount of porosities. In the tensile tests of FCD50, the joint efficiency was 79 to 94%, joint strength increasing with an increase in percent elongation. Fracture in the impact tests occurred in the bond zones both with SUS304 insert metal (1,2 pass welding) and pure nickel (1,2 pass welding). Impact values exhibited considerable scattering without regard to the existence of porosities. It was shown that the welded joints of FCD45(SUS304 insert metal, 3 pass welding) have sufficient strength, because fracture in the fatigue tests occurred in the base metals.抄録全体を表示PDF形式でダウンロード (723K) -
高柳 猛, 片島 三朗1988 年 60 巻 11 号 p. 672-676
発行日: 1988/11/25
公開日: 2011/09/08
ジャーナル フリーZirconia was examined with the application of the molding refractory for the single crystal casting of Ni-base super alloy.
Ni-base single crystal alloy, Alloy 454, was melt and held in the crucible of CaO stabilized zirconia at 1,500°C-1,540°C for 1-2 hours under the reduced pressure 2X10-4 Torr. The results were summerized as follows.
1) The surface of the ingot melted at 1,500°C was relatively clean. In the case melted at 1,540°C, black colored film was formed on the almost part of the obtained ingot. The thickness of the film was about 3.2μm for 1 hour holding and 6.8μm for 2 hours.
2) Zr was detected from the film and it considered to form by the significant increase of oxygen vacancy in zirconia.
The contaminated surface layer which contained 0.05-0.2%Zr was estimated about 20-30μm.
3) The decrease in weight of 1-1.5g was recognized by the evaporation during at 1,540°C. Cr content in the evaporated metal was higher about 25% than the original alloy.抄録全体を表示PDF形式でダウンロード (717K) -
谷 耕治, 石束 昌治, 上田 俶完1988 年 60 巻 11 号 p. 677-682
発行日: 1988/11/25
公開日: 2011/09/08
ジャーナル フリーThe effect of plasma-sprayed coatings with white alumina, gray alumina, zirconia composite, magnesium zirconate, chromium carbide or NiCr alloy powder on the heat resistant cast steel was investigated. The plasma-sprayed alumina had the highest hardness and the least wear at 1,000°C. Hardness of the plasma sprayed chromium carbide, which contains NiCr alloy at the rate of about 25%, decreased rapidly from approximately 600°C and the chromium carbide was weared more easily than the heat resistant cast steel at 1,000°C. But the chromium carbide layer showed the best adhesion among the plasma-sprayed ceramics at heat cycles. Graded coatings improved more the adhesion of the plasma-sprayed ceramics at heat cycles. Laser irradiation to the sprayed ceramics sealed pores, but took place cracking except for the chromium carbide during cooling. Layers of the ceramics mixed with the chromium carbide and NiCr alloy are eliminated pores and had no cracks by laser irradiation.抄録全体を表示PDF形式でダウンロード (683K) -
牧村 実, 堺 邦益, 西山 幸夫, 田中 正則1988 年 60 巻 11 号 p. 683-687
発行日: 1988/11/25
公開日: 2011/09/08
ジャーナル フリーA basic study on Application of a new version of camshafts for industrial engines was carried out for reducing the cost and the weight.
Conventional camshafts were produced by hole-drilling of solid castings at the center into cored shape for weight reduction. While in this study a new method was examined where a cored, “near net shape” cast iron component was cast with a thin-walled steel tube inserted.
The major points investigated was 1) estimation of manufacturability by solidification thermal analysis, 2) determination of optimum tube geomerty by investigating the weld between a steel tube and a cast iron bulk, 3) assignment of strength and rigidity against static and cyclic bending loads.
Furthermore application of the basic findings to actual scaled-up mass production was investigated.抄録全体を表示PDF形式でダウンロード (614K) -
野口 徹, 名雪 東彦, 高木 武, 高橋 典夫1988 年 60 巻 11 号 p. 688-693
発行日: 1988/11/25
公開日: 2011/09/08
ジャーナル フリーHigh nickel low thermal expansion cast irons with CV graphite were produced, and the thermal and the mechanical properties were compared with flake and spheroidal graphite irons. The CV treatment by Mg-Ca-Ti ferroalloy produced CV graphite in austenitic matrix. However, the graphite shape was highly dependent on the section thickness, treatment temperature and other pouring conditions as well as on the amount of the alloy. Thermal expansion coefficient depends mainly on the Ni content, also on the Si content, but not on the graphite shape. With 33∼36%Ni, the expansion coefficient was 3.5∼5.8×10-6/°C at temperatures of 0∼130°C, 1/3∼1/2 of ordinary cast irons ; at higher temperatures up to 200°C, it increased to 6.3∼7.8×10-5/°C. The mechanical properties of CV graphite iron were, 1.0∼1.3×104kgf/mm2 elastic modulus, 28∼40kgf/mm2 tensile strength, 5∼12% elongation and 120∼140 Brinell hardness, the range between flake and spheroidal graphite irons. The magnetic transformation temperature, Tm, was 120∼260°C, correlating well with the thermal expansion coefficient smaller for higher Tm.抄録全体を表示PDF形式でダウンロード (746K)
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