Abstract: There is provided a method for manufacturing a turbine component which enables obtaining a single crystal structure more easily and manufacturing a good turbine component. In the seed crystal placing step, the seed crystal is placed on the surface of the base in a manner that a first direction along <001> of the seed crystal has an angle within 15 degrees in absolute value in relation to a laminating direction. In the shaped layer forming step, scanning is performed in a manner that the scan direction has an angle within 20 degrees in absolute value in relation to a second direction being <001> orthogonal to the first direction of the seed crystal.

Abstract: A welding method, which subjects a surface to be built-up of an elongated workpiece to a build-up welding process along a longitudinal direction of the workpiece, includes a step for forming a build-up layer on the surface to be built-up by supplying a filler metal to the surface to be built-up along the longitudinal direction and by applying a laser beam thereto to melt the filler metal. A refrigerant is supplied to the surface to be built-up of the workpiece, during the step for forming the build-up layer.

Abstract: The supercritical CO2 turbine in an embodiment includes: a rotary body; a stationary body housing the rotary body inside; and a turbine stage including a stator blade cascade in which a plurality of stator blades are supported inside the stationary body, and a rotor blade cascade in which a plurality of rotor blades are supported by the rotary body inside the stationary body, in which a supercritical CO2 working medium is introduced into the inside of the stationary body and flows via the turbine stage in an axial direction of the rotary body to thereby rotate the rotary body. Here, a thermal conductivity k1 and a specific heat c1 of a material constituting the rotary body and a thermal conductivity k2 and a specific heat c2 of a material constituting the stationary body satisfy a relationship represented by the following formula (A).

Abstract: A double-walled tube includes: a plurality of double-walled tube forming members, each having an inner tube and an outer tube, connected by welding at welding portions of axis direction end portions thereof; and each of the welding portions of the double-walled tube forming members including a groove having a length in an axis direction set to be equal to or greater than ½ of a width of a weld bead formed by the welding at the welding portion.

Abstract: A method for repairing gas turbine blades includes: a thickness-reduced portion removing step S101 of working a surface of a blade tip 10a into a flat surface 13 by removing a thickness-reduced portion 12 of the blade tip 10a; a build-up welding step S102 of forming a built-up portion 14 with a predetermined thickness by melting powder of a build-up material higher in ductility than a base material forming the gas turbine blade 10 by a laser beam and building up the melted powder in multiple layers on the blade tip 10a whose surface is worked into the flat surface 13; a forming step S103 of working the built-up portion 14 into the same shape as a shape that the blade tip 10a originally has before suffering a thickness loss; and a heat-treatment step S104 of removing a residual strain caused by laser welding in the build-up welding step S102.

Abstract: A nickel-base single-crystal superalloy, essentially consists of, in percentages by weight, 4.0% to 11.0% of cobalt, 3.5% to less than 5.0% of chromium, 0.5% to 3.0% of molybdenum, 7.0% to 10.0% of tungsten, 4.5% to 6.0% of aluminum, 0.1% to 2.0% of titanium, 5.0% to 8.0% of tantalum, 1.0% to 3.0% of rhenium, 0.01% to 0.5% of hafnium, 0.01% to 0.1% of silicon, and a balance being nickel and inevitable impurity, a total amount of rhenium and chromium being not less than 4.0% and a total amount of rhenium, molybdenum, tungsten and chromium being not more than 18.0%.

Abstract: A nickel-base single-crystal superalloy, essentially consists of, in percentages by weight, 4.0% to 11.0% of cobalt, 3.5% to less than 5.0% of chromium, 0.5% to 3.0% of molybdenum, 7.0% to 10.0% of tungsten, 4.5% to 6.0% of aluminum, 0.1% to 2.0% of titanium, 5.0% to 8.0% of tantalum, 1.0% to 3.0% of rhenium, 0.01% to 0.5% of hafnium, 0.01% to 0.1% of silicon, and a balance being nickel and inevitable impurity, a total amount of rhenium and chromium being not less than 4.0% and a total amount of rhenium, molybdenum, tungsten and chromium being not more than 18.0%.

Abstract: The invention relates to a nickel-base single-crystal superalloy applied to parts for industrial gas turbine or the like such as turbine rotor blade and stator blade which are used at high temperatures, a method for manufacturing the same, and gas turbine parts prepared from such nickel-base single-crystal superalloys, and more particularly the invention provides a nickel-base single-crystal superalloy consisting essentially of, in percentages by weight, 5% to 10% cobalt, 4.7% to 6% chromium, more than 2.0% to less than 3.5% molybdenum, 7.5% to 10% tungsten, 5% to 6% aluminum, 0.1% to 2% titanium, 4% to 5.5% tantalum, 1% to 4% rhenium, 0.01% to 0.2% hafnium, the balance being nickel and incidental impurities, which is excellent in high-temperature strength and high-temperature corrosion resistance, and further excellent in structural stability even in a long time use.