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 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: 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 hydrogen pressure vessel capable of preventing hydrogen-induced cracking of a cylinder is provided. In a hydrogen pressure vessel according to one embodiment, a gap part (G) in which an inner peripheral surface of a cylinder (10) is spaced apart from an outer peripheral surface of a lid (20) is provided between a female thread part (10a) of the cylinder (10) into which the lid (20) is screwed, and a resin seal member (30), and the cylinder (10) includes a first through hole (41) for discharging gas in the gap part (G) into a relief pipe (51) and a second through hole (42) for introducing gas containing oxygen into the gap part (G) formed therein.

Abstract: The present invention provides a pressure vessel for hydrogen in which the development of cracking in the pressure vessel for hydrogen can be effectively inhibited and that is excellent in terms of safety, reliability, and durability. The present invention pertains to a pressure vessel for hydrogen in which a plastic region is present on the inner face side of a hydrogen pressure vessel main body, an elastic region is present on the outer face side, and compressive residual stress is generated on the inner face, wherein preferably: the equivalent plastic strain remaining on the inner surface of the hydrogen pressure vessel main body is 1% or below; the plastic region on the inner face side measures 50% or less of the wall thickness in the radial direction of the hydrogen pressure vessel main body; and the steel used has a tensile strength of at least 725 MPa.

Abstract: An accumulator vessel (10) includes a screwable portion (3) and a lid portion (2) that is positioned at an axially inner side of the screwable portion and an axially inner surface configures a pressure bearing plane. The lid portion includes a protruding portion (22) extending axially outward on an inner circumferential side, and the protruding portion configured to abut against an axially inner end side of the screwable portion to separate an axially inner surface of the screwable portion on an outer circumferential side thereof apart from an axially outer surface of the lid portion on an outer circumferential side thereof.

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: A hoop wrapped composite pressure vessel (1A) is provided in which a dome portion of a vessel main body (1) has a greater thickness than a thickness of a circularly cylindrical portion (2) and has a shape in which an outer circumferential curved surface initiating point (30A) that is situated axially outwards of an external diametrical surface (20) of the vessel main body that is flat in an axial direction is offset further axially outwards than an internal circumferential curved surface initiating point (31A) that is situated axially outwards of an internal diametrical surface (21) of the vessel main body that is flat in the axial direction and in which an FRP (10) is wound like a hoop around the vessel main body properly.

Abstract: An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel having high-pressure hydrogen environment embrittlement resistance characteristics, which has a composition comprising C: 0.10 to 0.20% by mass, Si: 0.10 to 0.40% by mass, Mn: 0.50 to 1.20% by mass, Ni: 0.75 to 1.75% by mass, Cr: 0.20 to 0.80% by mass, Cu: 0.10 to 0.50% by mass, Mo: 0.10 to 1.00% by mass, V: 0.01 to 0.10% by mass, B: 0.0005 to 0.005% by mass and N: 0.01% by mass or less, and further comprising one or two of Nb: 0.01 to 0.10% by mass and Ti: 0.005 to 0.050% by mass, with the balance consisting of Fe and unavoidable impurities.

Abstract: An accumulator vessel (10) includes a screwable portion (3) and a lid portion (2) that is positioned at an axially inner side of the screwable portion and an axially inner surface configures a pressure bearing plane. The lid portion includes a protruding portion (22) extending axially outward on an inner circumferential side, and the protruding portion configured to abut against an axially inner end side of the screwable portion to separate an axially inner surface of the screwable portion on an outer circumferential side thereof apart from an axially outer surface of the lid portion on an outer circumferential side thereof.

Abstract: In a method of determining a fatigue crack lifetime of a low-alloy steel material coming in contact with high-pressure hydrogen in a high-pressure hydrogen environment, estimate a fatigue crack acceleration starting point KmaxT of the low-alloy steel material using a crack-growth threshold stress intensity factor KIH-R obtained through a rising load test on the low-alloy steel material in a high-pressure hydrogen environment. The high-pressure hydrogen environment of the rising load test is a high-pressure hydrogen environment which has the same pressure and atmosphere as in the high-pressure hydrogen environment in which KmaxT is estimated and in which the test temperature tolerance between both environments is ±5° C.

Abstract: An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel having high-pressure hydrogen environment embrittlement resistance characteristics, which has a composition comprising C: 0.10 to 0.20% by mass, Si: 0.10 to 0.40% by mass, Mn: 0.50 to 1.20% by mass, Ni: 0.75 to 1.75% by mass, Cr: 0.20 to 0.80% by mass, Cu: 0.10 to 0.50% by mass, Mo: 0.10 to 1.00% by mass, V: 0.01 to 0.10% by mass, B: 0.0005 to 0.005% by mass and N: 0.01% by mass or less, and further comprising one or two of Nb: 0.01 to 0.10% by mass and Ti: 0.005 to 0.050% by mass, with the balance consisting of Fe and unavoidable impurities.

Abstract: An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel having high-pressure hydrogen environment embrittlement resistance characteristics, which has a composition comprising C: 0.10 to 0.20% by mass, Si: 0.10 to 0.40% by mass, Mn: 0.50 to 1.20% by mass, Ni: 0.75 to 1.75% by mass, Cr: 0.20 to 0.80% by mass, Cu: 0.10 to 0.50% by mass, Mo: 0.10 to 1.00% by mass, V: 0.01 to 0.10% by mass, B: 0.0005 to 0.005% by mass and N: 0.01% by mass or less, and further comprising one or two of Nb: 0.01 to 0.10% by mass and Ti: 0.005 to 0.050% by mass, with the balance consisting of Fe and unavoidable impurities.

Abstract: In a method of determining a fatigue crack lifetime of a low-alloy steel material coming in contact with high-pressure hydrogen in a high-pressure hydrogen environment, estimate a fatigue crack acceleration starting point KmaxT of the low-alloy steel material using a crack-growth threshold stress intensity factor KIH-R obtained through a rising load test on the low-alloy steel material in a high-pressure hydrogen environment. The high-pressure hydrogen environment of the rising load test is a high-pressure hydrogen environment which has the same pressure and atmosphere as in the high-pressure hydrogen environment in which KmaxT is estimated and in which the test temperature tolerance between both environments is ±5° C.

Abstract: An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel excellent in high-pressure hydrogen environment embrittlement resistance characteristics, which is characterized in that the steel has a composition comprising C: 0.10 to 0.20%, Si: 0.10 to 0.40%, Mn: 0.50 to 1.20%, Cr: 0.20 to 0.80%, Cu: 0.10 to 0.50%, Mo: 0.10 to 1.00%, V: 0.01 to 0.10%, B: 0.0005 to 0.005% and N: 0.01% or less, by mass, with the balance consisting of Fe and unavoidable impurities.

Abstract: A method of determining fatigue of a pressure-resistant component for high-pressure hydrogen made of a ferritic steel and provided in a high-pressure hydrogen gas environment is provided wherein when the material of the ferritic steel in the air has an ultimate tensile strength Su in the range of 958-1,144 MPa and the hydrogen gas environment has a pressure in a range to 45 MPa, then a fatigue strength in a gaseous hydrogen SH (MPa) for the pressure-resistant component provided in the high-pressure hydrogen gas environment is obtained by using equation (1): SH (MPa)=2,577?1.8925×Su (MPa). The influence of a high-pressure hydrogen gas environment on the pressure-resistant component for high-pressure hydrogen is determined based on the fatigue strength obtained by using the equation (1).

Abstract: A method of determining fatigue of a pressure-resistant component for high-pressure hydrogen made of a ferritic steel and provided in a high-pressure hydrogen gas environment is provided wherein when the material of the ferritic steel in the air has an ultimate tensile strength Su in the range of 958-1,144 MPa and the hydrogen gas environment has a pressure in a range to 45 MPa, then a fatigue strength in a gaseous hydrogen SH (MPa) for the pressure-resistant component provided in the high-pressure hydrogen gas environment is obtained by using equation (1): SH (MPa)=2,577?1.8925×Su (MPa). The influence of a high-pressure hydrogen gas environment on the pressure-resistant component for high-pressure hydrogen is determined based on the fatigue strength obtained by using the equation (1).

Abstract: An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel having high-pressure hydrogen environment embrittlement resistance characteristics, which has a composition comprising C: 0.10 to 0.20% by mass, Si: 0.10 to 0.40% by mass, Mn: 0.50 to 1.20% by mass, Ni: 0.75 to 1.75% by mass, Cr: 0.20 to 0.80% by mass, Cu: 0.10 to 0.50% by mass, Mo: 0.10 to 1.00% by mass, V: 0.01 to 0.10% by mass, B: 0.0005 to 0.005% by mass and N: 0.01% by mass or less, and further comprising one or two of Nb: 0.01 to 0.10% by mass and Ti: 0.005 to 0.050% by mass, with the balance consisting of Fe and unavoidable impurities.

Abstract: An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel excellent in high-pressure hydrogen environment embrittlement resistance characteristics, which is characterized in that the steel has a composition comprising C: 0.10 to 0.20%, Si: 0.10 to 0.40%, Mn: 0.50 to 1.20%, Cr: 0.20 to 0.80%, Cu: 0.10 to 0.50%, Mo: 0.10 to 1.00%, V: 0.01 to 0.10%, B: 0.0005 to 0.005% and N: 0.01% or less, by mass, with the balance consisting of Fe and unavoidable impurities.

Abstract: Using information about the position, orientation, and shape of a crack appeared in a judged material and information about the structure of the judged material as parameters, the stress intensity factor KI of the crack is found. Based on the stress intensity factor KI, hydrogen embrittlement cracking of the judged material is judged. The crack growth rate and possibility of brittle fracture can be judged by comparing the stress intensity factor KI with the critical stress intensity factor KIH for crack initiation or the critical stress intensity factor KIC-H for brittle fracture about the temper embrittled steel which absorbs approximately 2.0 ppm hydrogen.