Abstract: A method of manufacturing a steam turbine rotor which includes an ultra-high temperature side portion in which ultra-high temperature steam flows and a high temperature side portion in which high temperature steam flows, the manufacturing method including the steps of: preparing a first electrode having a chemical composition corresponding to a chemical composition of a heat resistant alloy making up the ultra-high temperature side portion and a second electrode having a chemical composition corresponding to a chemical composition of the high temperature side portion; tentatively joining together joints of the electrodes, with the joints of the electrodes made smaller in cross sectional area than other electrode portions; subjecting the tentatively joined first and second electrodes to an ESR process to obtain an ESR ingot and forging the ingot into a shape of a rotor to obtain a rotor forging; and heat-treating the rotor forging to obtain a rotor blank and manufacturing the steam turbine rotor from the rotor

Abstract: A precipitation hardening type martensitic stainless steel of an embodiment contains: Cr: 8.5 to 12.5%; Mo: 1 to 2%; Ni: 8.5 to 11.5%; Ti: 0.6 to 1.4%; C: 0.0005 to 0.05%; Al: 0.0005 to 0.25%; Cu: 0.005 to 0.75%; Nb: 0.0005 to 0.3%; Si: 0.005 to 0.75%; Mn: 0.005 to 1%; and N: 0.0001 to 0.03% by mass, and the balance of Fe and unavoidable impurities.

Abstract: A heat resistant cast steel containing, in mass %, C: 0.05-0.15, Si: 0.03-0.2, Mn: 0.1-1.5, Ni: 0.1-1, Cr: 8-10.5, Mo: 0.2-1.5, V: 0.1-0.3, Co: 0.1-5, W: 0.1-5, N: 0.005-0.03, Nb: 0.01-0.2, B: 0.002-0.015, Ti: 0.01-0.1, Fe and unavoidable impurities. A method for manufacturing a heat resistant cast steel, the method including melting raw materials to obtain a molten metal, refining and degassing the molten metal, pouring the molten metal into a predetermined mold to form a shape, performing an annealing treatment at a temperature of 1000 to 1150° C., performing a normalizing treatment at a temperature of 1000 to 1200° C., performing a first stage tempering treatment at a temperature of 500 to 700° C., and performing a second stage tempering treatment at a temperature of 700 to 780° C.

Abstract: A low alloy steel ingot contains from 0.15 to 0.30% of C, from 0.03 to 0.2% of Si, from 0.5 to 2.0% of Mn, from 0.1 to 1.3% of Ni, from 1.5 to 3.5% of Cr, from 0.1 to 1.0% of Mo, and more than 0.15 to 0.35% of V, and optionally Ni, with a balance being Fe and unavoidable impurities. Performing quality heat treatment including a quenching step and a tempering step to the low alloy steel ingot to obtain a material, which has a grain size number of from 3 to 7 and is free from pro-eutectoid ferrite in a metallographic structure thereof, and which has a tensile strength of from 760 to 860 MPa and a fracture appearance transition temperature of not higher than 40° C.

Abstract: A forging heat resistant steel of an embodiment contains in percent by mass C: 0.05-0.2, Si: 0.01-0.1, Mn: 0.01-0.15, Ni: 0.05-1, Cr: 8 or more and less than 10, Mo: 0.05-1, V: 0.05-0.3, Co: 1-5, W: 1-2.2, N: 0.01 or more and less than 0.015, Nb: 0.01-0.15, B: 0.003-0.03, and a remainder comprising Fe and unavoidable impurities.

Abstract: An Ni-base alloy for a turbine rotor of a steam turbine contains in percent by weight C: 0.01 to 0.15, Cr: 15 to 28, Co: 10 to 15, Mo: 8 to 12, Al: 1.5 to 2, Ti: 0.1 to 0.6, B: 0.001 to 0.006, Re: 0.5 to 3, and the balance of Ni and unavoidable impurities.

Abstract: In a brazing repair material 3 which is charged into a repairing portion of base material 1 in which a failure such as a crack 2 and corrosion is generated, diffusion heat treatment is carried out, the brazing repair material 3 is integrally bonded to the repairing portion to repair the repairing portion, the brazing repair material 3 comprises a mixture of non-molten alloy powder having a composition similar to that of the base material 1 and molten alloy powder which is melted at a temperature of the diffusion heat treatment, and the molten alloy powder is brazing repairing alloy consisting of 0.001 to 0.05 mass % of C, 2 to 5 mass % of Si, 10 to 25 mass % of Cr, 15 to 25 mass % of Co, 1 to 5 mass % of B, and balance of Ni, and excluding Al. With this configuration, a part having a failure such as a crack can restore original characteristics like the inherent base material.

Abstract: A precipitation hardening type martensitic stainless steel of an embodiment contains: Cr: 8.5 to 12.5%; Mo: 1 to 2%; Ni: 8.5 to 11.5%; Ti: 0.6 to 1.4%; C: 0.0005 to 0.05%; Al: 0.0005 to 0.25%; Cu: 0.005 to 0.75%; Nb: 0.0005 to 0.3%; Si: 0.005 to 0.75%; Mn: 0.005 to 1%; and N: 0.0001 to 0.03% by mass, and the balance of Fe and unavoidable impurities.

Abstract: A low alloy steel ingot contains from 0.15 to 0.30% of C, from 0.03 to 0.2% of Si, from 0.5 to 2.0% of Mn, from 0.1 to 1.3% of Ni, from 1.5 to 3.5% of Cr, from 0.1 to 1.0% of Mo, and more than 0.15 to 0.35% of V, and optionally Ni, with a balance being Fe and unavoidable impurities. Performing quality heat treatment including a quenching step and a tempering step to the low alloy steel ingot to obtain a material, which has a grain size number of from 3 to 7 and is free from pro-eutectoid ferrite in a metallographic structure thereof, and which has a tensile strength of from 760 to 860 MPa and a fracture appearance transition temperature of not higher than 40 ° C.

Abstract: A heat resistant cast steel of an embodiment contains in percent by mass C: 0.05-0.15, Si: 0.03-0.2, Mn: 0.1-1.5, Ni: 0.1-1, Cr: 8-10.5, Mo: 0.2-1.5, V: 0.1-0.3, Co: 0.1-5, W: 0.1-5, N: 0.005-0.03, Nb: 0.01-0.2, B: 0.002-0.015, Ti: 0.01-0.1, and a remainder comprising Fe and unavoidable impurities.

Abstract: A forging heat resistant steel of an embodiment contains in percent by mass C: 0.05-0.2, Si: 0.01-0.1, Mn: 0.01-0.15, Ni: 0.05-1, Cr: 8 or more and less than 10, Mo: 0.05-1, V: 0.05-0.3, Co: 1-5, W: 1-2.2, N: 0.01 or more and less than 0.015, Nb: 0.01-0.15, B: 0.003-0.03, and a remainder comprising Fe and unavoidable impurities.

Abstract: A method of manufacturing a steam turbine rotor which includes an ultra-high temperature side portion in which ultra-high temperature steam flows and a high temperature side portion in which high temperature steam flows, the manufacturing method including the steps of: preparing a first electrode having a chemical composition corresponding to a chemical composition of a heat resistant alloy making up the ultra-high temperature side portion and a second electrode having a chemical composition corresponding to a chemical composition of the high temperature side portion; tentatively joining together joints of the electrodes, with the joints of the electrodes made smaller in cross sectional area than other electrode portions; subjecting the tentatively joined first and second electrodes to an ESR process to obtain an ESR ingot and forging the ingot into a shape of a rotor to obtain a rotor forging; and heat-treating the rotor forging to obtain a rotor blank and manufacturing the steam turbine rotor from the rotor

Abstract: In a brazing repair material 3 which is charged into a repairing portion of base material 1 in which a failure such as a crack 2 and corrosion is generated, diffusion heat treatment is carried out, the brazing repair material 3 is integrally bonded to the repairing portion to repair the repairing portion, the brazing repair material 3 comprises a mixture of non-molten alloy powder having a composition similar to that of the base material 1 and molten alloy powder which is melted at a temperature of the diffusion heat treatment, and the molten alloy powder is brazing repairing alloy consisting of 0.001 to 0.05 mass % of C, 2 to 5 mass % of Si, 10 to 25 mass % of Cr, 15 to 25 mass % of Co, 1 to 5 mass % of B, and balance of Ni, and excluding Al. With this configuration, a part having a failure such as a crack can restore original characteristics like the inherent base material.

Abstract: An Ni-base alloy for a turbine rotor of a steam turbine contains in percent by weight C: 0.01 to 0.15, Cr: 15 to 28, Co: 10 to 15, Mo: 8 to 12, Al: 1.5 to 2, Ti: 0.1 to 0.6, B: 0.001 to 0.006, Re: 0.5 to 3, and the balance of Ni and unavoidable impurities.

Abstract: A Nickel-based alloy for a turbine rotor of a steam turbine contains C: 0.01 to 0.15, Cr: 18 to 28, Co: 10 to 15, Mo: 8 to 12, Al: 1.5 to 2, Ti: 0.1 to 0.6, B: 0.001 to 0.006, Ta: 0.1 to 0.7 in % by weight, and the remaining portion is composed of Ni and unavoidable impurities. The Nickel-based alloy is composed of the above-stated chemical composition range, and thereby, a mechanical strength improves while maintaining forgeability as same as a conventional steel.