Abstract: A gas pressure vessel capable of performing processing of removing wrinkles on an inner surface of a dome part and preventing cracking starting from a root of a thread of a neck part is provided. In a gas pressure vessel according to one embodiment, a dome part (12) has an opening whose diameter is 90 mm or greater, and the innermost root of the thread in a female thread part (10a) into which a lid (20) is screwed is provided inside an imaginary plane (B) formed by extending an outer surface of the dome part (12) toward an opening.

Abstract: A pressure container for crystal production having excellent corrosion-resistance is provided. This pressure container produces crystals within the container using a seed crystal, a mineralizer, a raw material, and ammonia in a supercritical state or a subcritical state as a solvent. The pressure container has Ag present over the entire surface of at least the inner surface thereof in contact with the solvent. The Ag can be disposed by one or a combination of two or more among, for instance, Ag lining, Ag welding, and Ag plating. The mineralizer is preferably a fluorine mineralizer containing no halogen atoms other than fluorine.

Abstract: A pressure vessel (10) is provided with: a cylinder part (1) that defines a pressure chamber (11); a screwing part (3) that is disposed inside at least one of the two ends of the cylinder part; a lid (2) that has a pressure-receiving surface (2A) facing the pressure chamber and that is disposed at a position closer to the pressure chamber than is the screwing part; and a reinforcing ring (4) that is fitted to the outer circumferential surface of the cylinder part. The reinforcing ring covers, along the axial direction of the cylinder part, a part on an outer circumferential surface (1F) corresponding to a portion or the entirety of the engaging portion (12) between the cylinder part and the screwing part.

Abstract: The purpose of the present invention is to enhance the creep characteristics of an Ni-based alloy. The present invention relates to a Ni-based alloy characterized by having a composition containing, in terms of wt %, 15.00-25.00% Cr, 5.00-15.00% Co, 1.00% to less than 12.00% Mo, 1.50-2.50% Ti, 1.00-2.00% Al, 0.20-1.00% Nb, and 0.0010-0.10% C, and in terms of mass ppm, 10-200 ppm P, 30-250 ppm B, and 30-200 ppm N, the remainder comprising Ni and unavoidable impurities.