Abstract: To provide a rotor material preferable for a steam turbine of which main steam temperature is 675° C. or more, particularly exceeding 700° C., and a steam turbine plant having a rotor formed by the material, the invention provides a steam turbine plant including a very-high-pressure turbine of which steam inlet temperature is 675 to 725° C. and steam outlet temperature is 650° C. or less, a high-pressure turbine, and a medium-low-pressure turbine, wherein a rotor of the very-high-pressure turbine is formed from a forged material of NiFe-base alloy containing: 14 to 18 weight % Cr, 15 to 45 weight % Fe, 1.0 to 2.0 weight % Al, 1.0 to 1.8 weight % Ti, C and N of which the sum is 0.05 or less weight %, and Nb in the range specified by the formula: 3.5?(Fe weight %)/20<(Nb weight %)<4.5?(Fe weight %)/20.

Abstract: A high-temperature steam turbine plant is of the top turbine type and structured as follows. It comprises a boiler building including a vertical boiler on the top of which a VHT turbine is installed; and a turbine building installed on the ground as a base. The VHT turbine and a generator connected with it are installed on the top of the boiler. The material for the portion of the steam pipe between the boiler building and the turbine building which is exposed to highest steam pressure is austenite steel which contains 50 weight % or more of ferrite steel or Fe. The inlet temperature of the VHT turbine is 675° C. or more and its outlet temperature is 550° C. or more and 650° C. or less.

Abstract: An Ni—Fe based superalloy forging material including 30 to 40 wt % of Fe, 14 to 16 wt % of Cr, 1.2 to 1.7 wt % of Ti, 1.1 to 1.5 wt % of Al, 1.9 to 2.7 wt % of Nb, 0.05 wt % or less of C and the remainder of Ni and inevitable impurities is solution-treated and aged, and thereby ?? phase (Ni3Al) having an initial mean particle size of about 50 to about 100 nm is precipitated. This superalloy is excellent in high-temperature strength and high-temperature ductility and can produce a large forged product of 10 ton or more. Therefore, this material is suitable for use as the material of a steam turbine rotor having a main steam temperature of 650° C. or more.

Abstract: A ?? phase strengthened Fe—Ni base superalloy comprising 1.0 to 3.0 wt % of Nb, 10 to 20 wt % of Cr, 30 to 50 wt % of Fe, 1.0 to 2.0 wt % of Ti, 1.0 to 2.0 wt % of Al, 0.02 wt % or less of C, the balance being Ni and inevitable impurities wherein an area of NbC in a cross sectional structure thereof is 0.4% or less. A hydrogen flow meter for high pressure hydrogen that uses the Fe—Ni base superalloy material mentioned-above.

Abstract: A welding material composition, which is a nickel based super alloy having ?? phase and chromium carbides precipitated. The composition comprising 18 to 25% by weight of Co, 15 to 20% by weight of Cr, 1.5 to 5.5% by weight of Al, 5 to 14% by weight of W, 0.05 to 0.15% by weight of C, 0 to 0.02% by weight of B, 0 to 1% by weight of at least one of Ta, Nb, Ti, Mo, Re and Fe, 0 to 0.5% by weight of at least one of V, Zr, rare earth elements and Y, 0 to 1% by weight of Mn, 0 to 0.5% by weight of Si, and the balance being Ni.

Abstract: A welding material composition, which is a nickel based super alloy having ?? phase and chromium carbides precipitated. The composition comprising 18 to 25% by weight of Co, 15 to 20% by weight of Cr, 1.5 to 5.5% by weight of Al, 5 to 14% by weight of W, 0.05 to 0.15% by weight of C, 0 to 0.02% by weight of B, 0 to 1% by weight of at least one of Ta, Nb, Ti, Mo, Re and Fe, 0 to 0.5% by weight of at least one of V, Zr, rare earth elements and Y, 0 to 1% by weight of Mn, 0 to 0.5% by weight of Si, and the balance being Ni.

Abstract: A Ni—Fe based super alloy having high strength and toughness at high temperatures even when used in high-temperature environments, and a process of producing the super alloy. A turbine disk using the super alloy, a process of producing the turbine disk, a turbine spacer using the super alloy, and a process of producing the turbine spacer, as well as a gas turbine are also provided. The Ni—Fe based super alloy contains not more than 0.03% by weight of C, 14-18% of Cr, 15-45% of Fe, 0.5-2.0% of Al, not more than 0.05% of N, 0.5 to 2.0% of Ti, 1.5-5.0% of Nb, and Ni as a main ingredient.

Abstract: To provide a rotor material preferable for a steam turbine of which main steam temperature is 675° C. or more, particularly exceeding 700° C., and a steam turbine plant having a rotor formed by the material, the invention provides a steam turbine plant including a very-high-pressure turbine of which steam inlet temperature is 675 to 725° C. and steam outlet temperature is 650° C. or less, a high-pressure turbine, and a medium-low-pressure turbine, wherein a rotor of the very-high-pressure turbine is formed from a forged material of NiFe-base alloy containing: 14 to 18 weight % Cr, 15 to 45 weight % Fe, 1.0 to 2.0 weight % Al, 1.0 to 1.8 weight % Ti, C and N of which the sum is 0.05 or less weight %, and Nb in the range specified by the formula: 3.5−(Fe weight %)/20<(Nb weight %)<4.5−(Fe weight %)/20.

Abstract: A welding material composition, which is a nickel based super alloy having &ggr;′ phase and chromium carbides precipitated. The composition comprising 18 to 25% by weight of Co, 15 to 20% by weight of Cr, 1.5 to 5.5% by weight of Al, 5 to 14% by weight of W, 0.05 to 0.15% by weight of C, 0 to 0.02% by weight of B, 0 to 1% by weight of at least one of Ta, Nb, Ti, Mo, Re and Fe, 0 to 0.5% by weight of at least one of V, Zr, rare earth elements and Y, 0 to 1% by weight of Mn, 0 to 0.5% by weight of Si, and the balance being Ni.

Abstract: A steam turbine blade made of Ti-base alloy comprising an &agr;+&bgr; type phase in which a difference of a tensile strength is small between a blade portion and a dovetail portion, a tensile strength at a room temperature of the dovetail portion is equal to or more than 100 kg/mm2 and a suitable toughness is commonly provided together with a strength, as a steam turbine blade having a length of 43 inch or more, a method of manufacturing the same, a steam turbine power generating plant and a low pressure steam turbine.

Abstract: There is provided a steam turbine blade made of Ti-base alloy comprising an &agr;+&bgr; type phase in which a difference of a tensile strength is small between a blade portion and a dovetail portion, a tensile strength at a room temperature of the dovetail portion is equal to or more than 100 kg/mm2 and a suitable toughness is commonly provided together with a strength, as a steam turbine blade having a length of 43 inch or more, a method of manufacturing the same, a steam turbine power generating plant and a low pressure steam turbine.

Abstract: There is provided a steam turbine blade made of Ti-base alloy comprising an &agr;+&bgr; type phase in which a difference of a tensile strength is small between a blade portion and a dovetail portion, a tensile strength at a room temperature of the dovetail portion is equal to or more than 100 kg/mm2 and a suitable toughness is commonly provided together with a strength, as a steam turbine blade having a length of 43 inch or more, a method of manufacturing the same, a steam turbine power generating plant and a low pressure steam turbine.