Abstract: An oxide film removing method is a method of removing an oxide film formed in a surface of a superalloy part that contains a first metal as a base metal and a second metal different from the first metal. The oxide film removing method includes arranging the superalloy part inside a heating chamber; reducing the oxide of the base metal to the base metal by heating the inside of the heating chamber in a condition that a reduction gas atmosphere or a vacuum atmosphere is maintained; and carrying out acid processing to apply acid solution to the superalloy part after the reduction. The oxide film formed in the surface of the superalloy is removed effectively without using a highly toxic gaseous fluoride.

Abstract: A gas turbine includes downstream side members that face a passage and have guide faces arranged in the passage side as it goes toward the upstream side. In a cross section including an axis center of a rotor shaft extending in a flow direction of a gas main stream, extension sections of the guide faces continuing to the upstream end portion of the guide faces are arranged downstream from the cavity inner wall portion of the upstream side member facing the cavities.

Abstract: A gas turbine includes downstream side members that face a passage and have guide faces arranged in the passage side as it goes toward the upstream side. In a cross section including an axis center of a rotor shaft extending in a flow direction of a gas main stream, extension sections of the guide faces continuing to the upstream end portion of the guide faces are arranged downstream from the cavity inner wall portion of the upstream side member facing the cavities.

Abstract: To provide a bearing support structure and a gas turbine that prevent damage of device induced by a rotor shaft when the rotor shaft is unbalanced, the bearing support structure and the gas turbine includes: a casing (7) formed in a cylindrical shape; a bearing unit (8) formed in a cylindrical shape and housed in the casing (7); a rotation shaft (5) rotatably supported by the bearing unit (8); and a reaction-force decreasing unit (13) that connects the casing and the bearing unit, and is configured to decrease a radial reaction force on the bearing unit side.

Abstract: To provide a bearing support structure and a gas turbine that prevent damage of device induced by a rotor shaft when the rotor shaft is unbalanced, the bearing support structure and the gas turbine includes: a casing (7) formed in a cylindrical shape; a bearing unit (8) formed in a cylindrical shape and housed in the casing (7); a rotation shaft (5) rotatably supported by the bearing unit (8); and a reaction-force decreasing unit (13) that connects the casing and the bearing unit, and is configured to decrease a radial reaction force on the bearing unit side.