Abstract: A light guide plate according to one or more embodiments may include an incident surface that receives light and an optical path changer on a back surface perpendicular to the incident surface. Light reflected by the optical path changer forms a stereoscopic image including a near formed image at an imaging position within a predetermined distance from the back surface and a distant formed image at another imaging position. The near formed image includes an image formation area with a larger total area than an image formation area of the distant formed image.

Abstract: A light guide plate according to one or more embodiments may include an incident surface that receives light, and an optical path changer on a back surface perpendicular to the incident surface. The optical path changer may reflect light to be emitted through an emission surface parallel to the back surface. The light emitted through the emission surface may form a formed image including a plane image representing a surface. The plane image may include a near imaging portion and a distant imaging portion. The plane image may have two ends included in the near imaging portion in a cross section perpendicular to the back surface and an optical axis of a light source.

Abstract: An optical device includes: a light guide plate having a group of optical-path deflectors configured to change the optical path of light from a first light source to form an image in the space within a first angle range, and change the optical path of light from a second light source to form an image in the space within a second angle range, wherein the first angle range and the second angle range are separated from each other or adjoining each other.

Abstract: An electric resistance welded steel pipe for a torsion beam, in which a base metal portion includes, in terms of % by mass, 0.04 to 0.12% of C, 0.03 to 1.20% of Si, 0.30 to 2.50% of Mn, 0.08 to 0.24% of Ti, 0.005 to 0.500% of Al, 0.01 to 0.06% of Nb, and 0.0005 to 0.0100% of N, a balance including Fe and impurities, wherein Vc90, defined by the following Formulae (i) and (ii), is 200 or more, a mass ratio of Ti content to C content is from 0.85 to 5.00, an areal ratio of ferrite is 80% or more, an average crystal grain size of ferrite crystal grains is 10 ?m or less, and an average aspect ratio of ferrite crystal grains is 2.0 or less, in a metallographic microstructure of a central portion in a wall thickness direction of the base metal portion; log Vc90=2.94?0.75(?a?1)??Formula (i); ?a=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo??Formula (ii).

Abstract: The present invention relates to steel pipe excellent in toughness of the weld metal part at a low temperature obtained by submerged arc welding in the longitudinal direction from both the inside and outside surfaces having strengths of the X60 to X70 class. The steel pipe of the present invention is a pipe having weld zones welded in a longitudinal direction at an inside surface and outside surface, wherein the tensile strength of the base metal is 480 to 620 MPa, the weld metal has a predetermined composition of constituents, when % X expresses a content of an element X in the weld metal, Pcm defined by Pcm=% C+% Si/30+(% Mn+% Cu+% Cr)/20+% Ni/60+% Mo/15+% V/10+5% B is 0.2% or less, Ceq defined by Ceq=% C+% Mn/6+(% Cr+% Mo+% V)/5+(% Ni+% Cu)/15 is 0.35 to 0.45%, ?? defined by ??=(1.5×(% O?0.89% Al)+3.4×% N?% Ti)×1000 is ?20 to 40, and % Al/% O is 0.3 to 0.8.

Abstract: The present invention relates to steel pipe excellent in toughness of the weld metal part at a low temperature obtained by submerged arc welding in the longitudinal direction from both the inside and outside surfaces having strengths of the X60 to X70 class. The steel pipe of the present invention is a pipe having weld zones welded in a longitudinal direction at an inside surface and outside surface, wherein the tensile strength of the base metal is 480 to 620 MPa, the weld metal has a predetermined composition of constituents, when % X expresses a content of an element X in the weld metal, Pcm defined by Pcm=% C+% Si/30+(% Mn+% Cu+% Cr)/20+% Ni/60+% Mo/15+% V/10+5% B is 0.2% or less, Ceq defined by Ceq=% C+% Mn/6+(% Cr+% Mo+% V)/5+(% Ni+% Cu)/15 is 0.35 to 0.45%, and ?? defined by ??=(1.5×(% O-0.89% Al)+3.4×% N-% Ti)×1000 is ?20 to 40, and % Al/% O is 0.3 to 0.8.

Abstract: A pipeline is a pipeline having plural weld zones in which ends of plural steel pipes are joined by welding, the plural steel pipes are produced from plural charges of molten steel having one or more steel compositions; yield point elongation is not present on a stress-strain curve obtained when stress is applied in a longitudinal direction of each of the steel pipes; a thickness of each of the steel pipes t (mm) and an average pipe outside-diameter D (mm) satisfy t/D×100?6; and in the plurality of the weld zones, ?YS which is a yield strength difference between one steel pipe and the other steel pipe that are welded to each other (MPa), and YR representing a yield ratio that is a ratio of the yield strength to tensile strength of a pipe having a low yield strength out of the one steel pipe and the other steel pipe, satisfy ?YS??1.75×YR+230.

Abstract: An electric resistance welded steel pipe for a torsion beam, in which a base metal portion includes, in terms of % by mass, 0.04 to 0.12% of C, 0.03 to 1.20% of Si, 0.30 to 2.50% of Mn, 0.08 to 0.24% of Ti, 0.005 to 0.500% of Al, 0.01 to 0.06% of Nb, and 0.0005 to 0.0100% of N, a balance including Fe and impurities, wherein Vc90, defined by the following Formulae (i) and (ii), is 200 or more, a mass ratio of Ti content to C content is from 0.85 to 5.00, an areal ratio of ferrite is 80% or more, an average crystal grain size of ferrite crystal grains is 10 ?m or less, and an average aspect ratio of ferrite crystal grains is 2.0 or less, in a metallographic microstructure of a central portion in a wall thickness direction of the base metal portion; log Vc90=2.94?0.75(?a?1)??Formula (i); ?a=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo??Formula (ii).

Abstract: A pipeline is a pipeline having plural weld zones in which ends of plural steel pipes are joined by welding, the plural steel pipes are produced from plural charges of molten steel having one or more steel compositions; yield point elongation is not present on a stress-strain curve obtained when stress is applied in a longitudinal direction of each of the steel pipes; a thickness of each of the steel pipes t (mm) and an average pipe outside-diameter D (mm) satisfy t/D×100?6; and in the plurality of the weld zones, ?YS which is a yield strength difference between one steel pipe and the other steel pipe that are welded to each other (MPa), and YR representing a yield ratio that is a ratio of the yield strength to tensile strength of a pipe having a low yield strength out of the one steel pipe and the other steel pipe, satisfy ?YS??1.75×YR+230.

Abstract: A pipeline is a pipeline having plural weld zones in which ends of plural steel pipes are joined by welding, the plural steel pipes are produced from plural charges of molten steel having one or more steel compositions; yield point elongation is not present on a stress-strain curve obtained when stress is applied in a longitudinal direction of each of the steel pipes; a thickness of each of the steel pipes t (mm) and an average pipe outside-diameter D (mm) satisfy t/D×100?6; and in the plurality of the weld zones, ?YS which is a yield strength difference between one steel pipe and the other steel pipe that are welded to each other (MPa), and YR representing a yield ratio that is a ratio of the yield strength to tensile strength of a pipe having a low yield strength out of the one steel pipe and the other steel pipe, satisfy ?YS??1.75×YR+230.

Abstract: An electric resistance welded steel pipe which has sufficient strength and low-temperature toughness and a low yield ratio and which is suitable as a line pipe to be laid in depths of the sea, characterized in that: the composition of the base material contains, in mass %, 0.05 to 0.10% of C, 1.00 to 1.60% of Mn, and 0.005 to less than 0.035% of Nb, and has a Ceq value of 0.23 to 0.38; and the metal microstructure of the base material contains 3 to 13% of martensite in area fraction with the balance being ferrite.

Abstract: An electric resistance welded steel pipe which has sufficient strength and low-temperature toughness and a low yield ratio and which is suitable as a line pipe to be laid in depths of the sea, characterized in that: the composition of the base material contains, in mass %, 0.05 to 0.10% of C, 1.00 to 1.60% of Mn, and 0.005 to less than 0.035% of Nb, and has a Ceq value of 0.23 to 0.38; and the metal microstructure of the base material contains 3 to 13% of martensite in area fraction with the balance being ferrite.

Abstract: A liquid phase diffusion bonded pipe joint comprised of metal pipes or a metal pipe and a joint pipe joined by liquid phase diffusion bonding, the liquid phase diffusion bonded pipe joint comprised of a metal joint provided with a tapered slanted part press-fit into an end of a metal pipe by a thrust in a pipe axial direction while expanding the metal pipe in inside diameter and tightly engaging with the end and a joining surface part continuing from the tapered slanted part and joined with an end face of the metal pipe by liquid phase diffusion bonding and a metal pipe tightly engaging with the tapered slanted part in the expanded state and with an end face joined with the joining surface part by liquid phase diffusion bonding.

Abstract: A pipeline is a pipeline having plural weld zones in which ends of plural steel pipes are joined by welding, the plural steel pipes are produced from plural charges of molten steel having one or more steel compositions; yield point elongation is not present on a stress-strain curve obtained when stress is applied in a longitudinal direction of each of the steel pipes; a thickness of each of the steel pipes t (mm) and an average pipe outside-diameter D (mm) satisfy t/Dx100?6; and in the plurality of the weld zones, ?YS which is a yield strength difference between one steel pipe and the other steel pipe that are welded to each other (MPa), and YR representing a yield ratio that is a ratio of the yield strength to tensile strength of a pipe having a low yield strength out of the one steel pipe and the other steel pipe, satisfy ?YS??1.75×YR+230.

Abstract: The present invention provides a thick welded steel pipe excellent in low temperature toughness in which contents of Mn and Mo satisfy (Expression 1) below, Pcm obtained by (Expression 2) below is 0.16 to 0.19, and a metal structure of a base material steel plate consists of ferrite being 30 to 95% in an area ratio and a low temperature transformation structure, and in a metal structure of a coarse-grained HAZ, an area ratio of grain boundary ferrite is 1.5% or more, the total area ratio of the grain boundary ferrite and intragranular ferrite is not less than 11% nor more than 90%, an area ratio of MA is 10% or less, and its balance is composed of bainite. 1.2325?(0.85×[Mn]?[Mo])?1.5215??(Expression 1) and Pcm=[C]+[Si]/30+([Mn]+[Cu]+[Cr])/20+[Ni]/60+[Mo]/15+[V]/10??(Expression 2).

Abstract: The present invention provides high strength steel plate and high strength welded pipe excellent in ductile fracture characteristic and methods of production of the same, that is, high strength steel plate excellent in ductile fracture characteristic, and high strength welded pipe using that steel plate as a base material, having a tensile strength corresponding to the X100 class of the API standard, containing, by mass %, C: 0.01 to 0.5%, Si: 0.01 to 3%, Mn: 0.1 to 5%, P: 0.03% or less, and S: 0.03% or less and a balance of Fe and unavoidable impurities, having a microstructure comprised of, by area ratio, 1 to 60% of ferrite and the balance of bainite and martensite, having a maximum value of the {100} accumulation degree of the cross-section rotated 20 to 50° from the plate thickness cross-section about the rolling direction as an axis of 3 or less, and having plate thickness parallel cracks measured by ultrasonic flaw detection of less than 1 mm.

Abstract: This high-strength steel pipe includes, by mass %, C: 0.02% to 0.09%, Mn: 0.4% to 2.5%, Cr: 0.1% to 1.0%, Ti: 0.005% to 0.03%, Nb: 0.005% to 0.3%, and a balance consisting of Fe and inevitable impurities, in which Si, Al, P, S, and N are limited to 0.6% or less, 0.1% or less, 0.02% or less, 0.005% or less, 0.008% or less, respectively, the bainite transformation index BT is 650° C. or less, and the microstructure thereof is a single bainite microstructure including first bainite and second bainite, the first bainite being a gathered microstructure of bainitic ferrite including no carbide, and the second bainite being a mixed microstructure of bainitic ferrite including no carbide and cementite between the bainitic ferrites.

Abstract: The present invention provides a thick welded steel pipe excellent in low temperature toughness in which contents of Mn and Mo satisfy (Expression 1) below, Pcm obtained by (Expression 2) below is 0.16 to 0.19, and a metal structure of a base material steel plate consists of ferrite being 30 to 95% in an area ratio and a low temperature transformation structure, and in a metal structure of a coarse-grained HAZ, an area ratio of grain boundary ferrite is 1.5% or more, the total area ratio of the grain boundary ferrite and intragranular ferrite is not less than 11% nor more than 90%, an area ratio of MA is 10% or less, and its balance is composed of bainite. 1.2325?(0.85×[Mn]?[Mo])?1.

Abstract: This high-strength steel pipe includes, by mass%, C: 0.02% to 0.09%, Mn: 0.4% to 2.5%, Cr: 0.1% to 1.0%, Ti: 0.005% to 0.03%, Nb: 0.005% to 0.3%, and a balance consisting of Fe and inevitable impurities, in which Si, Al, P, S, and N are limited to 0.6% or less, 0.1% or less, 0.02% or less, 0.005% or less, 0.008% or less, respectively, the bainite transformation index BT is 650° C. or less, and the microstructure thereof is a single bainite microstructure including first bainite and second bainite, the first bainite being a gathered microstructure of bainitic ferrite including no carbide, and the second bainite being a mixed microstructure of bainitic ferrite including no carbide and cementite between the bainitic ferrites.

Abstract: The present invention provides a line pipe of, e.g., the API standard X60 to X100 class. The line pipe has an excellent deformability, as well as excellent low temperature toughness and high productivity, a steel plate used as the material of the steel pipe. Methods for producing the steel pipe and the steel plate are also provided. In particular, a high-strength steel plate excellent in the deformability has a ferrite phase is dispersed finely, and accounts for 5% to 40% in area percentage in a low temperature transformation structure mainly composed of a bainite phase. For example, most grain sizes of the ferrite phase are smaller than the average grain size of the bainite phase. A high-strength steel pipe excellent in deformability is also provided, in which a large diameter steel pipe is produced through forming the steel plate into a pipe shape. The steel pipe has the above-referenced structure, and satisfies the conditions that YS/TS is 0.95 or less and YS×uEL is 5,000 or more.