Hitachi Metals, Ltd.

Masahide Kawabata

Kenichi Inoue

Kana Morishita

Toru Iwanaga

Lin Wang

Susumu Katsuragi

Kiyoshi Suehara

Yutaka Morita

Masafumi Kokubo

Tomonori Sakuta

Toshihiro Uehara

Katsuhiko Kojo

Masahiro Takahashi

Koki Otsuka

Senri Okada

Hideya Yamane

Yoshio Igarashi

Kentaro Fukumoto

Seiichi Endo

Masanori Hara

Toshiki Yoshida

Yoshimasa Fujii

Junji Hayakawa

Kenya Matsuyama

Hideharu Nakano

Hideo Kuribayashi

Morishita Kana

A casting apparatus for producing a casting by pouring a metal melt into a gas-permeable casting mold by gravity, comprising: a gas-permeable casting mold comprising a cavity including a sprue composed of a tubular portion and a cup portion having a larger diameter than that of the tubular portion to receive the metal melt, a runner constituting a flow path of the metal melt supplied through the sprue, and a product-forming cavity to be filled with the metal melt sent through the runner; a means for pouring the metal melt into the sprue by gravity; a gas-blowing unit comprising a gas-ejecting member to be connected to the sprue; and a mechanism for moving the gas-ejecting member; the gas-ejecting-member-moving mechanism placing the gas-ejecting member at a position just above the tubular portion and not interfering with gravity pouring of the metal melt, and moving it downward for connection to the tubular portion; the gas-blowing unit having blowing a gas to fill the product-forming cavity with the metal melt.

Casting apparatus and method for producing castings using it

A spheroidal graphite cast iron having (a) a composition comprising by mass 3.4-4% of C, 1.9-2.8% of Si, 0.02-0.06% of Mg, 0.2-1% of Mn, 0.2-2% of Cu, 0-0.1% of Sn, 0.85-3% of (Mn+Cu+10&#xd7;Sn), 0.05% or less of P, and 0.02% or less of S, the balance being Fe and inevitable impurities, and (b) a duplex matrix structure comprising by area 2-40% of fine ferrite phases and 60-98% of fine pearlite phases, the maximum length of the ferrite phases being 300 &#x3bc;m or less, and (c) the pearlite phases being formed around graphite particles dispersed in the duplex matrix structure.

Spheroidal graphite cast iron having excellent strength and toughness and its production method

A heat-resistant, austenitic cast steel having excellent machinability comprising by mass 0.4-0.55% of C, 1-2% of Si, 0.5-1.5% of Mn, 18-27% of Cr, 8-22% of Ni, 1.5-2.5% of Nb, 0.01-0.3% of N, 0.1-0.2% of S, and 0.02-0.15% of Al, the balance being Fe and inevitable impurities, a machinability index I represented by the following formula: I=100&#xd7;S+75&#xd7;Al+0.75&#xd7;Mn&#x2212;10&#xd7;C&#x2212;2&#xd7;Nb&#x2212;0.25&#xd7;Cr&#x2212;0.15&#xd7;Ni&#x2212;1.2&#xd7;N, wherein each element symbol represents % by mass of each element in the cast steel, meeting the condition of &#x2212;3.0&#x2266;I&#x2266;+14.0, and an exhaust member made thereof.

Heat-resistant, austenitic cast steel having excellent machinability and exhaust member made thereof

A heat-resistant, cast ferritic steel having excellent machinability comprising by mass 0.32-0.48% of C, 0.85% or less of Si, 0.1-2% of Mn, 1.5% or less of Ni, 16-23% of Cr, 3.2-5% of Nb, Nb/C being 9-11.5, 0.15% or less of N, 0.05-0.2% of S, and 0.01-0.08% of Al, the balance being Fe and inevitable impurities, and an exhaust member made thereof.

Heat-resistant, cast ferritic steel having excellent machinability and exhaust member made thereof

A method for producing a casting by pouring a metal melt by gravity into a gas-permeable casting moldhaving a cavity comprising at least a sprue, a runnerand a product-forming cavity, comprising pouring a metal melt into a desired cavity portionincluding the product-forming cavity through the sprue, the melt being in a volume substantially equal to the volume of the desired cavity portion; supplying a gasto the desired cavity portion through the sprue before the desired cavity portion is filled with the poured melt, so that the melt fills the desired cavity portion; and cooling a portion of the melt in contact with the gas directly or indirectly by watersupplied from outside the gas-permeable casting mold, simultaneously with, during or after supplying the gas, thereby solidifying the melt.

Method for producing castings

Precipitation-hardened, martensitic, cast stainless steel having a composition comprising, by mass, 0.08-0.18% of C, 1.5% or less of Si, 2.0% or less of Mn, 0.005-0.4% of S, 13.5-16.5% of Cr, 3.0-5.5% of Ni, 0.5-2.8% of Cu, 1.0-2.0% of Nb, and 0.12% or less of N, the amounts of C, N and Nb meeting the condition of &#x2212;0.2&#x2266;9 (C %+0.86N %)&#x2212;Nb %&#x2266;1.0, the rest being Fe and inevitable impurities, and having a structure in which Cu precipitates having an average particle size of 0.1-0.4 &#x3bc;m are dispersed in a tempered-martensite-based matrix.

Precipitation-hardened, martensitic, cast stainless steel having excellent machinability and its production method

A heat-resistant, ferritic cast steel having excellent melt flowability, gas defect resistance, toughness and machinability, which has a composition comprising by mass, C: 0.32-0.45%, Si: 0.85% or less, Mn: 0.15-2%, Ni: 1.5% or less, Cr: 16-23%, Nb: 3.2-4.5%, Nb/C: 9-11.5, N: 0.15% or less, S: (Nb/20&#x2212;0.1) to 0.2%, W and/or Mo: 3.2% or less in total (W+Mo), the balance being Fe and inevitable impurities, and a structure in which the area ratio of a eutectic (&#x3b4;+NbC) phase of &#x3b4; ferrite and Nb carbide (NbC) is 60-80%, and the area ratio of manganese chromium sulfide (MnCr)S is 0.2-1.2%, and an exhaust member made thereof.

Heat-resistant, ferritic cast steel having excellent melt flowability, gas defect resistance, toughness and machinability, and exhaust member made thereof

A heat-resistant, ferritic cast steel having excellent room-temperature toughness, which has a composition comprising by mass 0.32-0.48% of C, 0.85% or less of Si, 2% or less of Mn, 1.5% or less of Ni, 16-19.8% of Cr, 3.2-5% of Nb, Nb/C being 9-11.5, 0.15% or less of N, 0.002-0.2% of S, and 0.8% or less in total of W and/or Mo, the balance being Fe and inevitable impurities, and a structure in which a eutectic (&#x3b4;+NbC) phase formed from a &#x3b4; phase and Nb carbide (NbC) has an area ratio of 60-90%, and an exhaust member made thereof.

Heat-resistant, ferritic cast steel having excellent room-temperature toughness, and exhaust member made thereof

Heat-resistant, austenitic cast steel comprising by mass 0.3-0.6% of C, 1.1-2% of Si, 1.5% or less of Mn, 17.5-22.5% of Cr, 8-13% of Ni, 1.5-4% as (W+2Mo) of at least one of W and Mo, 1-4% of Nb, 0.01-0.3% of N, 0.01-0.5% of S, the balance being Fe and inevitable impurities, and meeting the following formulae (1), (2), (3) and (4):0.05&#x2266;(C&#x2014;Nb/8)&#x2266;0.6&#x2003;&#x2003;(1),17.5&#x2266;17.5Si&#x2212;(W+2Mo)&#x2003;&#x2003;(2),5.6Si+(W+2Mo)&#x2266;13.7&#x2003;&#x2003;(3), and0.08Si+(C&#x2014;Nb/8)+0.015Cr+0.011Ni+0.03W+0.02Mo&#x3c;0.96&#x2003;&#x2003;(4),wherein the symbol of each element corresponds to the amount (% by mass) of each element in the cast steel.

Heat-resistant, austenitic cast steel and exhaust member made thereof

A low-thermal expansion cast steel having an average linear thermal expansion coefficient of less than 4.0&times;10 /&deg; C. in a range of room temperature to 100&deg; C. and excellent machinability has a chemical composition (by mass) comprising 0.4-0.8% of C, 0.5% or less of Si, 1.0% or less of Mn, 0.01-0.3% of S, 30-40% of Ni, and 0.005-0.1% of Mg, the balance being substantially Fe and inevitable impurities, the contents of S and Mn satisfying S&lE;(1/4) Mn or (1/4) Mn<S&lE;(1/4) Mn&plus;0.05.

Low-thermal expansion cast steel with excellent machinability

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.

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Moka, Japan

Masahide Kawabata