Hitachi Metals, Ltd.

Honda Motor Co., Ltd.

Hitachi, Ltd.

Babcock-hitachi Kabushiki Kaisha

Mitsubishi Hitachi Power Systems, Ltd.

Akihiro Toji

Toshihiro Uehara

Takehiro Ohno

Shinya Imano

Hiroyuki Doi

Katsuaki Sato

Katsuhiko Ohishi

Katsuhiko Tominaga

Takashi Sato

Gang Bao

Shoichi Nakaya

Satoshi Kubota

Motoi Yamaguchi

To provide an inexpensive heat-resisting steel for engine valves by causing Fe-based heat-resisting steel to exhibit high temperature strength not inferior to that of Ni-based heat-resisting steel. A heat-resisting steel for engine valves excellent in high temperature strength containing, in % by mass, C: 0.20 to 0.50%, Si: 1.0% or less, Mn: 5.0% or less, P: 0.1 to 0.5%, Ni: 8.0 to 15.0%, Cr: 16.0 to 25.0%, Mo: 2.0% or less (including 0%), Cu: 0.5% or less, Nb: 1.0% or less (including 0%), W: 2.0% or less (including 0%), N: 0.02 to 0.30%, B: 0.01% or less, and remnants of Fe and impurities, wherein the heat-resisting steel for engine valves satisfies formulae below:156.42P(%)+0.91Mo(%)+0.73W(%)&#x2212;12.27Nb(%)+220.96N(%)+120.59&#x2267;170&#x2003;&#x2003;Formula (1)13.70P(%)&#x2212;6.97Mo(%)&#x2212;4.32W(%)&#x2212;3.29Nb(%)+119.10N(%)+27.75&#x2267;25&#x2003;&#x2003;Formula (2).

Heat-resisting steel for engine valves excellent in high-temperature strength

Disclosed is a low-thermal-expansion Ni-based super-heat-resistant alloy for a boiler, which has excellent high-temperature strength. The alloy can be welded without the need of carrying out any aging treatment. The alloy has a Vickers hardness value of 240 or less. The alloy comprises (by mass) C in an amount of 0.2% or less, Si in an amount of 0.5% or less, Mn in an amount of 0.5% or less, Cr in an amount of 10 to 24%, one or both of Mo and W in such an amount satisfying the following formula: Mo+0.5 W=5 to 17%, Al in an amount of 0.5 to 2.0%, Ti in an amount of 1.0 to 3.0%, Fe in an amount of 10% or less, and one or both of B and Zr in an amount of 0.02% or less (excluding 0%) for B and in an amount of 0.2% or less (excluding 0%) for Zr, with the remainder being 48 to 78% of Ni and unavoidable impurities.

Low-thermal-expansion Ni-based super-heat-resistant alloy for boiler and having excellent high-temperature strength, and boiler component and boiler component production method using the same

A low cost, economical and less resource-consuming heat resistant alloy for use as material of engine valve is disclosed, while the alloy has excellent mechanical properties at high temperature and excellent toughness after heated for a long time that conventional heat resistant alloys have not had. The alloy consists essentially of, in mass percent, C of 0.01 to 0.15%, Si of 0.01 to 0.8%, Mn of 0.01 to 0.8, Cr of 14 to 17%, Mo of more than 3.0% but equal to or less than 5.0%, Al of 1.6 to 2.5%, Ti of 1.5 to 3.0%, Nb or Nb+Ta of 0.5 to 2.0%, Ni of 50 to 60%, B of 0.001 to 0.015%, at least one of Mg of 0.001 to 0.015% and Ca of 0.001 to 0.015%, and the balance being Fe,

Heat resistant alloy for use as material of engine valve

A nickel-based alloy is provided for provide parts and members of improved oxidation-resistance and high temperature strength for use in an oxidation atmosphere at high temperatures, such as automobile parts including an electrode for an ignition plug, power plant facility parts including a gas turbine nozzle, inner parts of heat treat furnaces, and fuel cell parts. The alloy improved in oxidation-resistance, high temperature strength and hot workability consists essentially of, in mass percentage, C: 0.003 to 0.1%, Si: 1.0% or less, Mn: 2.0% or less, Cr: 12 to 32%, Fe: 20% or less, Mg: 0.001 to 0.04%, at least one element, of not more than 2.5% in total, selected from the group consisting of Nb, Ta and V, impurity elements of S: 0.01% or less, but the ratio of the Mg-content to the S-content (Mg/S) being 1 or more, and Ti: 0 inclusive to 0.02%, and the rest being Ni and incidental impurities.

Ni-based alloy improved in oxidation-resistance, high temperature strength and hot workability

Steel for separators of solid-oxide type fuel cells

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Yasugi, Japan

Akihiro Toji