Hitachi Metals, Ltd.

Yoshio Igarashi

Shigeo Fujii

Masahide Kawabata

Tsunehiro Kawata

Juro Endo

Masahiro Takahashi

Katsuhiko Kojo

Shiro Murakami

Senri Okada

Seiichi Endo

Toshiki Yoshida

Masayuki Nakao

Masahiro Miyake

Kenya Matsuyama

Hideharu Nakano

Masanao Suzuki

Shigetaka Morita

A graphite-containing, heat-resistant cast iron for exhaust equipment members used at temperatures exceeding 800&#xb0; C., comprising 3.5-5.6% of Si and 1.2-15% of W on a weight basis, and having intermediate layers, in which W and Si are concentrated, in the boundaries of graphite particles and a matrix. An exhaust equipment member formed by this heat-resistant cast iron has an Atransformation point is 840&#xb0; C. or higher when measured from 30&#xb0; C. at a temperature-elevating speed of 3&#xb0; C./minute, and a thermal cracking life of 780 cycles or more in a thermal fatigue test, in which heating and cooling are conducted under the conditions of an upper-limit temperature of 840&#xb0; C., a temperature amplitude of 690&#xb0; C. and a constraint ratio of 0.25.

Heat-resistant cast iron and exhaust equipment member formed thereby

An additive for use in producing spheroidal graphite cast iron of the present invention contains a fine particle of magnesium oxide having a purity of 90 weight % or more and at least one selected from the group consisting of a graphite-spheroidizing material, an inoculant and a graphite-spheroidizing inoculant. The fine particle of highly pure magnesium oxide increases the number of nuclei in a melt, and as a result thereof, increases the graphite spheroid count of a spheroidal graphite cast iron being produced. Another additive for use in producing spheroidal graphite cast iron of the present invention contains at least one selected from the group consisting of a graphite-spheroidizing material, an inoculant and a graphite-spheroidizing inoculant, and an oxide of a metal which has, at a temperature of a melt at a time when subjected to a graphite-spheroidizing treatment, an affinity for oxygen smaller than that of a graphite-spheroidizing element being used in the graphite-spheroidizing treatment. By adding to the melt the metal oxide which oxidizes the graphite-spheroidizing element in the melt to an oxide thereof, a great number of fine oxide particles of the graphite-spheroidizing element is dispersed in the melt to provide a spheroidal graphite cast iron having a great number of fine graphite spheroids and a small chill area ratio.

Additive for use in producing spheroidal graphite cast iron

An aluminum alloy casting comprising 4.0 to 13.0% of Si, 4.5% or below of Cu, 1.5% or below of Mg, and the rest of Al in weight ratio is produced by a production method which adds a metallic hydride to a molten aluminum alloy for casting at a temperature of liquidus line or above. This method makes the shape of pores generated in the casting circular and fine, and an average crystal grain diameter to be 1/3 or below of a thickness of the casting, thereby, an aluminum alloy casting having excellent airtightness can be produced.

Airtight aluminum alloy casting and its manufacturing method

A manufacturing process of Co-Ni magnetic recording media by sputtering Co-Ni thin film layer on a substrate in Argon atmosphere including oxygen or air and heating the thin film to evaporate oxygen or air from the layer to prepare the magnetic recording media appropriate for high density longitudinal recording, wherein on sputtering the substrate is maintained at a temperature of room temperature to 300.degree. C.

Method of manufacturing a magnetic media

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Tochigi-ken, Japan

Yoshio Igarashi