Abstract: An Ni-based alloy for casting used for a steam turbine of an embodiment contains in percent (%) by mass C (carbon): 0.01 to 0.1, Cr (chromium): 15 to 25, Co (cobalt): 10 to 15, Mo (molybdenum): 5 to 12, Al (aluminum): 0.5 to 2, Ti (titanium): 0.3 to 2, B (boron): 0.001 to 0.006, Ta (tantalum): 0.05 to 1, Si (silicon): 0.1 to 0.5, Mn (manganese): 0.1 to 0.5, and the balance of Ni (nickel) 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 method for removing a crack in an electromechanical rotor, including: forming a plurality of slots on a periphery of a core portion of an electromechanical rotor along an axial direction thereof; inserting coils into the slots, respectively; forming a plurality of wedges for maintaining the coils in the slots, respectively; and forming a cut hole at at least a part of the core portion from an outer surface of the core portion toward the side of a center axis thereof so as to contain a crack along a circumferential direction thereof.

Abstract: An Ni-based alloy for casting used for a steam turbine of an embodiment contains in percent (%) by mass C (carbon): 0.01 to 0.1, Cr (chromium): 15 to 25, Co (cobalt): 10 to 15, Mo (molybdenum): 5 to 12, Al (aluminum): 0.5 to 2, Ti (titanium): 0.3 to 2, B (boron): 0.001 to 0.006, Ta (tantalum): 0.05 to 1, Si (silicon): 0.1 to 0.5, Mn (manganese): 0.1 to 0.5, and the balance of Ni (nickel) 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 method for repairing a crack in an electromechanical rotor (10), including forming a plurality of slots (12) on a periphery of a core portion (11) of an electromechanical rotor (10) along an axial direction thereof; inserting coils into the slots (12), respectively; forming a plurality of wedges for maintaining the coils in the slots (12), respectively; and forming a cut hole (20) at the core portion (11) from an outer surface of the core portion (11) so as to remove at least a deeper area of a crack created at the core portion (11) at a contacting surface between the corresponding wedge and the corresponding slot (12).

Abstract: A Ni-based alloy for a forged part of a steam turbine having excellent high temperature strength, forgeability and weldability includes, in percentage by mass, 0.01 to 0.15 of C, 18 to 28 of Cr, 10 to 15 of Co, 8 to 12 of Mo, 1.5 to 2 of Al, 0.1 to 3 of Ti, 0.001 to 0.006 of B, 0.1 to 0.7 of Ta, and the balance of Ni plus unavoidable impurities.

Abstract: A Ni-based alloy for a casting part of a steam turbine having excellent high temperature strength, castability and weldability includes, in percentage by mass, 0.01 to 0.15 of C, 18 to 28 of Cr, 10 to 15 of Co, 8 to 12 of Mo, 1.5 to 2 of Al, 0.1 to 3 of Ti, 0.001 to 0.006 of B, 0.1 to 0.7 of Ta, and the balance of Ni plus unavoidable impurities.

Abstract: An object of the present invention is to control crack propagation, either by predicting shaft dovetail crack propagation with high accuracy, or by determining operation conditions under which the crack does not extend. The crack propagation prediction system includes an operation processing unit, an interface unit, and a memory unit. The operation processing unit includes a stress calculation unit that calculates the mean stress generated in the shaft dovetail, a factor range calculation unit that calculates the stress intensity factor range for the crack in the shaft dovetail, and a crack propagation amount calculation unit that calculates an amount of the shaft dovetail crack propagation for an arbitrary time period, from the obtained mean stress and the stress intensity factor range, an operation pattern, an operation time, and data on the crack.

Abstract: A method for refurbishing service-degraded gas turbine component can recover the microstructure of the alloy of the gas turbine component, whose material is deteriorated or damaged after its operation, to the extent that is equivalent or more than the characteristic at the time of its manufacture. The method comprises performing a recovery heat treatment, performing a solution heat treatment, and performing an aging heat treatment. The recovery heat treatment heat-treats the component under a predetermined pressure, which is higher than normal pressure, wherein the temperature of the component is increased to a predetermined temperature under the predetermined pressure. The solution heat treatment is processed under reduced pressure or inert gas atmosphere after the recovery heat treatment. The aging heat treatment is processed under reduced pressure or inert gas atmosphere after the recovery heat treatment.

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: The present invention provides a coating method, in which a composite coating layer is formed on a surface of an alloy base member by utilizing a rotary electrode device. The coating method includes the steps of: preparing an electrolytic solution containing A ion wherein A is Co or Ni; preparing a MCrAlY powder wherein M denotes at least one element selected from the group consisting of Ni and Co, and the MCrAlY powder contains at least Ni when A is Co or the MCrAlY powder contains at least Co when A is Ni; preparing a dispersion liquid by dispersing the MCrAlY powder into the electrolytic solution; immerging the cylindrical rotary electrode and the alloy base member into the dispersion liquid; and electrolyzing the surface of the alloy base member while the cylindrical rotary electrode covered with the nonwoven fabric layer is rolled on the on the surface of the alloy base member thereby to form the composite coating layer onto the surface of the alloy base member.

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.

Abstract: A to-be-repaired damaged part, which occurs in a rotor, is removed and shaped by machining or grinding. The shaped surface, from which the to-be-repaired damaged part is removed in the step, is roughened by a blasting process. A coating is formed on the surface, which is roughened in the step, by a high-velocity flame spray apparatus. The coating, which is formed in the step, is finished by machining or polishing. A defect inspection is performed to check presence/absence of a defect. A dimensional/quality inspection is performed for the part repaired in the step.

Abstract: An object of the present invention is to control crack propagation, either by predicting shaft dovetail crack propagation with high accuracy, or by determining operation conditions under which the crack does not extend. The crack propagation prediction system includes an operation processing unit, an interface unit, and a memory unit. The operation processing unit includes a stress calculation unit that calculates the mean stress generated in the shaft dovetail, a factor range calculation unit that calculates the stress intensity factor range for the crack in the shaft dovetail, and a crack propagation amount calculation unit that calculates an amount of the shaft dovetail crack propagation for an arbitrary time period, from the obtained mean stress and the stress intensity factor range, an operation pattern, an operation time, and data on the crack.

Abstract: A method for removing a crack in an electromechanical rotor, including: forming a plurality of slots on a periphery of a core portion of an electromechanical rotor along an axial direction thereof; inserting coils into the slots, respectively; forming a plurality of wedges for maintaining the coils in the slots, respectively; and forming a cut hole at at least a part of the core portion from an outer surface of the core portion toward the side of a center axis thereof so as to contain a crack along a circumferential direction thereof.

Abstract: A method for repairing a crack in an electromechanical rotor (10), including forming a plurality of slots (12) on a periphery of a core portion (11) of an electromechanical rotor (10) along an axial direction thereof; inserting coils into the slots (12), respectively; forming a plurality of wedges for maintaining the coils in the slots (12), respectively; and forming a cut hole (20) at the core portion (11) from an outer surface of the core portion (11) so as to remove at least a deeper area of a crack created at the core portion (11) at a contacting surface between the corresponding wedge and the corresponding slot (12).

Abstract: A method of regenerating gas-turbine stator vane comprising the steps of: grinding the oxidized layer and the cracks 2 formed at surface portion so that a part of the cracks 2 remains; filling an equivalent material and a brazing material 4 into the ground portion, the equivalent material 3 having an equality with the base material 1 for the stator vane, and the brazing material 4 having a melting point lower than that of the equivalent material 3; heat treating the filled portion under pressurized inert gas atmosphere so as to melt the brazing material; performing brazing treatment by diffusing the molten brazing material into the cracked portions. According to the above method, the stator vane occurred with material deterioration and damages or the like due to operation of a gas turbine can be efficiently regenerated to provide a high quality without requiring to completely grinding and removing the cracks including a closed crack formed at surface of the stator vane.

Abstract: A method for refurbishing service-degraded gas turbine component can recover the microstructure of the alloy of the gas turbine component, whose material is deteriorated or damaged after its operation, to the extent that is equivalent or more than the characteristic at the time of its manufacture. The method comprises performing a recovery heat treatment, performing a solution heat treatment, and performing an aging heat treatment. The recovery heat treatment heat-treats the component under a predetermined pressure, which is higher than normal pressure, wherein the temperature of the component is increased to a predetermined temperature under the predetermined pressure. The solution heat treatment is processed under reduced pressure or inert gas atmosphere after the recovery heat treatment. The aging heat treatment is processed under reduced pressure or inert gas atmosphere after the recovery heat treatment.