Hitachi, Ltd.

Tetsuo Kashimura

Yutaka Fukui

Hiroyuki Doi

Shigeyoshi Nakamura

Nobuyuki Iizuka

Takanobu Mori

Yoshimi Yanai

Ken Yasuda

Fumio Hataya

Kishio Hidaka

Ryo Hiraga

Hideyo Kodama

Kazuya Nishi

Soichi Kurosawa

Minoru Morikawa

Shinichi Nakahara

A cylindrical gas turbine combustor, burning injected fuel and guiding the combustion gas to turbine nozzles, includes a cylindrical portion such as a combustor liner and a transition piece, exposed to the combustion gas, which is made of austenitic Fe base casting alloy, Ni base casting alloy or Co base casting alloy.

Gas turbine combustor and gas turbine

There is provided an oxide dispersion-strengthened nickel alloy which has a hot working property, a structure stability at high temperature, improved creep characteristics at high temperature and improved heat resistant fatigue characteristics. The oxide dispersion-strengthened alloy is composed of an oxide containing one or more kinds of elements in an amount of 2 wt % or less selected from the group composed of titanium, zirconium and hafnium, chromium in an amount of 15-35 wt %, carbon in an amount of 0.01-0.4 wt % and Y.sub.2 O.sub.3 in an amount of 0.3-2.0 wt %, and the balance of substantially nickel, wherein Y.sub.2 O.sub.3 is dispersed as particles in the matrix of the nickel alloy containing one or more kinds of elements selected from the group composed of titanium, zirconium and hafnium, chromium and carbon. The elements of equipment such as the nozzle guide vane of a gas turbine, the liner and transition piece of a combustor, and the like are composed of the oxide dispersion-strengthened alloy of the present invention so that they can be used at high temperature.

Oxide dispersion-strengthened alloy and high temperature equipment

A Ni-base superalloy consisting essentially of, by weight: 0.05 to 0.20% C, 20 to 25% Co, 15 to 25% Cr, 1.0 to 3.0% Al, 1.0 to 3.0% Ti, 1.0 to 3.0% Nb, 5 to 10% W, and at least 55% Ni, the combination of the [Al+Ti] and tungsten contents being determined as shown in FIG. 5. This superalloy has a high thermal-fatigue resistance, a great high-temperature strength, particularly, a great creep rupture strength, and a good weldability. The superalloy is used to form gas turbine nozzles, which are employed in a gas turbine. Using such a gas turbine, a combined power generating system is built.

Gas turbine and gas turbine nozzle

A Ni-base superalloy consisting essentially of, by weight: 0.05 to 0.20% C, 20 to 25% Co, 15 to 25% Cr, 1.0 to 3.0% Al, 1.0 to 3.0% Ti, 1.0 to 3.0% Nb, 5 to 10% W, and at least 42.5% Ni, the combination of the [Al+Ti] and tungsten contents being determined as shown in FIG. 5. This superalloy has a high thermal-fatigue resistance, a great high-temperature strength, particularly, a great creep rupture strength, and a good weldability. The superalloy is used to form gas turbine nozzles, which are employed in a gas turbine. Using such a gas turbine, a combined power generating system is built.

A gas turbine includes a turbine stubshaft, a plurality of turbine disks coupled to the shaft by turbine stacking bolts with spacers interposed therebetween, turbing moving blades planted in each of the disks, a shroud provided with a sliding surface in a spaced-apart relation to the tips of the moving blades, a distant piece connected to the disks by the bolts, a plurality of compressor disks coupled to the distant piece by compressor stacking bolts, compressor blades planted in each of the compressor disks, and a compressor stubshaft formed integrally with the compressor disk located at the first stage. At least a sliding portion of the shroud is made of a heat-resistant cast alloy having in turn a chilled layer and columnar grains in a direction oriented from the sliding surface thereof toward the interior thereof. A method of producing a segment-shaped shroud for a gas turbine by casting, comprises the steps of preparing a mold having a coated layer formed on at least a surface thereof which is to be in contact with a casting, the coated layer containing refractory aggregate powder at a main constituent, and refractory agent powder for accelerating generation of crystal nuclei, pouring the molten alloy into the mold, and forced-cooling the outer surface of the mold.

Gas turbine and shroud for gas turbine

A cobalt-base alloy comprises 0.2-1 wt % C 0.4-2 wt % Si, 0.2-1.5 wt % Mn, 5-15 wt % Ni, 20-35 wt % Cr, 3-15 wt % W, 0.003-0.1 wt % Ni, 20-35 wt % Cr, 3-15 wt % W, 0.003-0.1 wt % B, 0.05-1 wt % Nb, 0.01-1 wt % Ta, 2 wt % or less Fe, 30 ppm or less oxygen, 100 ppm or less nitrogen, and the balance of 45 wt % or more Co, wherein the content of Si is larger than that of Mn. The alloy is in a form of casting and has a structure containing a eutectic carbide and a secondary carbide dispersed therein. The cast alloy is produced through solution treatment at 1,100.degree.-1.200.degree. C., and aging treatment at 950.degree.-1,050.degree. C., and cooling rate after the solution treatment and after the aging treatment is 150.degree. to 300.degree. C./h. A gas turbine nozzle is made of a casting of the above-mentioned alloy.

Cobalt-base alloy having high strength and high toughness, production

An electric rotary machine (for example, a dynamoelectric machine) having a superconducting rotor is disclosed in which an outer shielding member for protecting a superconducting field winding from the influence of the magnetic flux from the stator side and for interrupting heat radiated from the normal temperature side is made of a nickel alloy containing not more than 0.3% carbon, not more than 1% silicon, not more than 2% manganese, not more than 1.5% titanium, from 2 to 8% aluminum, from 8 to 40% copper, and not less than 55% nickel for the balance by weight. The nickel alloy has a structure that a .gamma.'-phase precipitation is formed by aging in an austenitic matrix, and is non-magnetic at 20.degree. C.

Electric rotary machine having superconducting rotor

A gas turbine combustor defines a combustion chamber for combustion of injected fuel and for introduction of the resultant hot combustion gas to nozzles of a gas turbine. The combustor has parts subjected to hot combustion gas during operation of the turbine, such as a cap connected to a fuel injection nozzle, a liner connected to the cap, and a transition piece connected to the liner. These parts subjected to the hot combustion gas are made from an alloy having a composition consisting essentially of 0.02 to 0.2 wt % of C, 15 to 30 wt % of Cr and 10 to 25 wt % of W.

Gas turbine combustor

A cobalt base alloy having a superior high-temperature strength and high-temperature ductility, containing, by weight, 0.15 to 2% carbon, less than 2% silicon, less than 2% manganese, 5 to 15% nickel, 18 to 35% chromium, 3 to 15% tungsten, 0.003 to 0.1% boron, 0.01 to 1% niobium, 0.01 to 1% zirconium, less than 110% iron, less than 1% tantalum, less than 1% hafnium and remainder cobalt. At least one of 0.01 to 1 wt% titanium and 0.01 to 1 wt% (combined amount) rare earth elements is added to the alloy. The alloy is used as a casting and contains eutectic carbides and secondary carbides precipitated substantially uniformly in the grains. If the secondary carbides are formed by an age-treatment conducted at a higher temperature than that at which the alloy is actually used, the high-temperature strength and the high-temperature ductility of the alloy are remarkably improved. The cobalt base alloy is formed into gas turbine nozzles by a precision casting.

Cobalt base alloy

The present alloys of iron-nickel-chromium-molybdenum system are alloys having high strength and ductility, comprising 0.03-0.2% by weight of carbon, not more than 2% by weight of silicon, not more than 2% by weight of manganese, 42-70% by weight of nickel, 15-35% by weight of chromium, 4.5-15% by weight of molybdenum, 0.05-1.0% by weight of at least one of Ti and Nb as additive elements, and 7.5-35% by weight of iron, the balance being incidental impurities, or further contain 0.1-10% by weight of at least one of tungsten and cobalt as reinforcing elements.

Highly ductile alloys of iron-nickel-chromium-molybdenum system for gas

A cobalt base alloy consisting essentially of, in weight percent, about 0.1% to about 0.5% carbon, about 0.3% to about 2.0% silicon, about 0.3% to about 2.0% manganese, about 5.0% to about 15.0% nickel, about 26.0% to about 35.0% chromium, about 3.0% to about 10.0% tungsten, about 0.003% to about 0.1% boron, about 0.01% to about 1.0% titanium, about 0.01% to about 1.0% niobium and optionally about 0.05% to about 1.0% mischmetal and the balance being essentially cobalt together with impurities and incidental elements normally associated with a cobalt base alloy, which has high strength and high ductility even at high temperatures and is especially suitable as a material to be used at high temperatures under high thermal stress, such as a material for a nozzle of a gas turbine engine.

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Hitachi, Japan

Tetsuo Kashimura