Abstract: The present invention provides a method for producing a ring-rolled material of an Fe—Ni based superalloy which inhibits AGG, has a fine-grained structure having an ASTM grain size number of at least 8, and has high circularity. A method for producing a ring-rolled material of an Fe—Ni based superalloy having a composition of an Alloy 718 comprises: heating a ring-shaped material for ring rolling having the composition, in a temperature range of 900° C. to 980° C., and performing finishing ring rolling, as a finishing ring rolling step; heating the ring-rolled material that has been subjected to the finishing ring rolling, in a temperature range of 980 to 1010° C.; and correcting ellipticalness while expanding a diameter of the ring-rolled material by using a ring expander.

Abstract: The present invention provides a method for producing a ring-rolled material of an Fe—Ni based superalloy which inhibits AGG, has a fine-grained structure having an ASTM grain size number of at least 8, and has high circularity. A method for producing a ring-rolled material of an Fe—Ni based superalloy having a composition of an Alloy 718 comprises: heating a ring-shaped material for ring rolling having the composition, in a temperature range of 900° C. to 980° C., and performing finishing ring rolling, as a finishing ring rolling step; heating the ring-rolled material that has been subjected to the finishing ring rolling, in a temperature range of 980 to 1010° C.; and correcting ellipticalness while expanding a diameter of the ring-rolled material by using a ring expander.

Abstract: A method for producing a ring-rolled material of an Fe—Ni based superalloy, which has a high circularity, can inhibit AGG, and can inhibit grain growth. A method for producing a ring-rolled material of an Fe—Ni based superalloy having a composition of an Alloy 718 comprises: a finishing ring rolling step of heating a ring-shaped material for ring rolling having the composition, in a temperature range of 900° C. to 980° C., and performing finishing ring rolling; and a circularity correcting step of correcting an ellipticalness of the ring-rolled material that has been rolled in the finishing ring rolling step, while expanding a diameter of the ring-rolled material by using a ring expander including a pipe-expanding cone and a pipe-expanding die, wherein the ring-rolled material that has been rolled in the finishing ring rolling step is subjected to circularity correction without being reheated or after having been heated to up to 960° C.

Abstract: A method of producing a forged product is described, in which a forging component is hot-forged using a lower die and an upper die. The method includes a first process in which at least a part of an die face of the lower die is covered with a first glass lubricant; a second process in which the lower die is heated; a third process in which at least a part of the forging component is covered with a second glass lubricant; a fourth process in which the forging component is heated to a temperature that is higher than a heating temperature of the lower die in the second process; and a fifth process in which the forging component is placed on the die face of the lower die and hot forging is performed using the lower die and the upper die.

Abstract: A method of producing a forged product is described, in which a forging component is hot-forged using a lower die and an upper die. The method includes a first process in which at least a part of an die face of the lower die is covered with a first glass lubricant; a second process in which the lower die is heated; a third process in which at least a part of the forging component is covered with a second glass lubricant; a fourth process in which the forging component is heated to a temperature that is higher than a heating temperature of the lower die in the second process; and a fifth process in which the forging component is placed on the die face of the lower die and hot forging is performed using the lower die and the upper die.

Abstract: An acceleration sensor is disclosed that has a structure in which elastic support arms are not broken even if subjected to an impact that may be caused during a usual handling. The acceleration sensor comprises a mass portion, a mass portion top plate fixed onto the mass portion, a rectangular thick support frame surrounding the mass portion, a frame top plate fixed onto the frame, and four elastic support arms hanging the mass portion in the center of the frame and bridging the mass portion top plate and the frame top plate. There are provided lateral grooves just below the support arms on side surfaces of the mass portion and on inner side surfaces of the frame. Due to the grooves, the mass portion top plate and the frame top plate have their portions bonded to the mass portion/the frame and their portions protruding toward the support arms. Cross sections on boundaries between the bonded portions and the protruding portions are larger than those connecting the protruding portions to the support arms.

Abstract: An acceleration sensor is disclosed that has a structure in which elastic support arms are not broken even if subjected to an impact that may be caused during a usual handling. The acceleration sensor comprises a mass portion, a mass portion top plate fixed onto the mass portion, a rectangular thick support frame surrounding the mass portion, a frame top plate fixed onto the frame, and four elastic support arms hanging the mass portion in the center of the frame and bridging the mass portion top plate and the frame top plate. There are provided lateral grooves just below the support arms on side surfaces of the mass portion and on inner side surfaces of the frame. Due to the grooves, the mass portion top plate and the frame top plate have their portions bonded to the mass portion/the frame and their portions protruding toward the support arms. Cross sections on boundaries between the bonded portions and the protruding portions are larger than those connecting the protruding portions to the support arms.