A high-strength high-toughness electric-resistance-welded steel pipe having high resistance to post-weld heat treatment is provided. The steel pipe having a composition including C: 0.01% to 0.12%, Si: 0.05% to 0.50%, Mn: 1.0% to 2.2%, P: 0.03% or less, S: 0.005% or less, Al: 0.001% to 0.10%, N: 0.006% or less, Nb: 0.010% to 0.100%, and Ti: 0.001% to 0.050%. The steel pipe having a structure composed of 90% or more by volume of a bainitic ferrite phase and 10% or less (including 0%) by volume of a second phase. The bainitic ferrite phase having an average grain size of 10 μm or less, and the structure containing fine Nb precipitates having a particle size of less than 20 nm dispersed in a base material portion. The steel pipe having high strength and toughness that is maintained through post-weld heat treatment, including heating to a temperature of 600° C. or more.

A method of manufacturing a seamless stainless steel pipe for Oil Country Tubular Goods by heating a billet having a specified chemical composition including forming the billet into a seamless steel pipe by applying hot working to the billet, cooling the seamless steel pipe to a room temperature at a cooling rate of air cooling or more, thereafter, performing quenching by heating the seamless steel pipe to a temperature of 850° C. or above, subsequently, cooling the seamless steel pipe to a temperature of 100° C. or below at a cooling rate of air cooling or more, and subsequently, applying tempering to the seamless steel pipe at a temperature of 700° C. or below for a specific holding time.

A method of manufacturing a seamless stainless steel pipe for Oil Country Tubular Goods by heating a billet having a specified chemical composition including forming the billet into a seamless steel pipe by applying hot working to the billet, cooling the seamless steel pipe to a room temperature at a cooling rate of air cooling or more, thereafter, performing quenching by heating the seamless steel pipe to a temperature of 850° C. or above, subsequently, cooling the seamless steel pipe to a temperature of 100° C. or below at a cooling rate of air cooling or more, and subsequently, applying tempering to the seamless steel pipe at a temperature of 700° C. or below for a specific holding time.

A low-alloy steel has a composition including, by mass %, C: more than 0.45 and up to 0.65%; Si: 0.05 to 0.50%; Mn: 0.10 to 1.00%; P: up to 0.020%; S: up to 0.0020%; Cu: up to 0.1%; Cr: 0.40 to 1.50%; Ni: up to 0.1%; Mo: 0.50 to 2.50%; Ti: up to 0.01%; V: 0.05 to 0.25%; Nb: 0.005 to 0.20%; Al: 0.010 to 0.100%; B: up to 0.0005%; Ca: 0 to 0.003%; 0: up to 0.01%; N: up to 0.007%; and other elements. A microstructure consists of tempered martensite and retained austenite<2% in volume fraction, crystal grain size number being 9.0 or larger, number density of carbonitride-based inclusions with grain diameter of 50 μm or larger being 10 inclusions/100 mm.sup.2 or smaller, and yield strength being 965 MPa or higher.

A low-alloy steel has a composition including, by mass %, C: more than 0.45 and up to 0.65%; Si: 0.05 to 0.50%; Mn: 0.10 to 1.00%; P: up to 0.020%; S: up to 0.0020%; Cu: up to 0.1%; Cr: 0.40 to 1.50%; Ni: up to 0.1%; Mo: 0.50 to 2.50%; Ti: up to 0.01%; V: 0.05 to 0.25%; Nb: 0.005 to 0.20%; Al: 0.010 to 0.100%; B: up to 0.0005%; Ca: 0 to 0.003%; 0: up to 0.01%; N: up to 0.007%; and other elements. A microstructure consists of tempered martensite and retained austenite<2% in volume fraction, crystal grain size number being 9.0 or larger, number density of carbonitride-based inclusions with grain diameter of 50 μm or larger being 10 inclusions/100 mm.sup.2 or smaller, and yield strength being 965 MPa or higher.

A method is used to manufacture an article using a machine having a fixed base and a press structure movable toward the fixed base. The machine also includes a die assembly and a container both coupled to the fixed base. The machine further includes a mandrel assembly comprising a rotatable platform coupled to the press structure and having a first platform mandrel aligned with the die assembly and a second platform mandrel aligned with the container. The method includes the steps of placing a first starting component into the die assembly, pressing the first starting component to form the article, moving the second platform mandrel into the container simultaneously with the step of pressing the first starting component, and rotating the rotatable platform to align the second platform mandrel with the die assembly and to align the first platform mandrel with the container.

Provided is steel for nitrocarburizing with excellent surface fatigue strength. The steel has a nitride compound layer with a thickness of 5.0 μm to 30.0 μm and a hardened layer in an order from a steel surface to steel inside, where a thickness of a porous layer on an outermost surface of the compound layer is 3.0 μm or less and 40.0% or less of a compound layer's thickness, the hardened layer has hardness of HV600 or more, HV400 or more and HV250 or more at 50 μm inward from the steel surface, from the steel surface to the steel inside of 400 μm, and from the steel surface to the steel inside of 600 μm, respectively, an unhardened portion excluding the compound and hardened layers has a predetermined chemical composition, and the hardened layer has a chemical composition with a higher N content than the unhardened portion.

A lens alignment system and method is disclosed. The disclosed system/method integrates one or more lens retaining members/tubes (LRM/LRT) and focal length spacers (FLS) each comprising a metallic material product (MMP) specifically manufactured to have a thermal expansion coefficient (TEC) in a predetermined range via selection of the individual MMP materials and an associated MMP manufacturing process providing for controlled TEC. This controlled LRM/LRT TEC enables a plurality of optical lenses (POL) fixed along a common optical axis (COA) by the LRM/LRT to maintain precise interspatial alignment characteristics that ensure consistent and/or controlled series focal length (SFL) within the POL to generate a thermally neutral optical system (TNOS). Integration of the POL using this LRM/LRT/FLS lens alignment system reduces the overall TNOS implementation cost, reduces the overall TNOS mass, reduces TNOS parts component count, and increases the reliability of the overall optical system.

A high-strength seamless steel pipe for oil country tubular goods comprising, by mass %, C: 0.20% to 0.50%, Si: 0.05% to 0.40%, Mn: 0.3% to 0.9%, P: 0.015% or less, S: 0.005% or less, Al: 0.005% to 0.1%, N: 0.006% or less, Mo: more than 1.0% to 3.0% or less, V: 0.01% to less than 0.05%, Nb: 0.001% to less than 0.01%, B: 0.0003% to 0.0030%, O: 0.0030% or less, and Ti: 0.003% to 0.025%, and wherein Ti/N: 2.0 to 5.0 is satisfied, a volume fraction of a tempered martensitic is 95% or more, prior austenite grains have a grain size number of 8.5 or more, and in a cross-section perpendicular to a rolling direction, the number of nitride-based inclusions having a grain size of 4 μm or more is 100 or less per 100 mm.sup.2, the number of nitride-based inclusions having a grain size of less than 4 μm is 1000 or less per 100 mm.sup.2, the number of oxide-based inclusions having a grain size of 4 μm or more is 40 or less per 100 mm.sup.2, and the number of oxide-based inclusions having a grain size of less than 4 μm is 400 or less per 100 mm.sup.2.

A high-strength seamless steel pipe for oil country tubular goods comprising, by mass %, C: 0.20% to 0.50%, Si: 0.05% to 0.40%, Mn: 0.3% to 0.9%, P: 0.015% or less, S: 0.005% or less, Al: 0.005% to 0.1%, N: 0.006% or less, Mo: more than 1.0% to 3.0% or less, V: 0.01% to less than 0.05%, Nb: 0.001% to less than 0.01%, B: 0.0003% to 0.0030%, O: 0.0030% or less, and Ti: 0.003% to 0.025%, and wherein Ti/N: 2.0 to 5.0 is satisfied, a volume fraction of a tempered martensitic is 95% or more, prior austenite grains have a grain size number of 8.5 or more, and in a cross-section perpendicular to a rolling direction, the number of nitride-based inclusions having a grain size of 4 μm or more is 100 or less per 100 mm.sup.2, the number of nitride-based inclusions having a grain size of less than 4 μm is 1000 or less per 100 mm.sup.2, the number of oxide-based inclusions having a grain size of 4 μm or more is 40 or less per 100 mm.sup.2, and the number of oxide-based inclusions having a grain size of less than 4 μm is 400 or less per 100 mm.sup.2.