Abstract: A seamless steel pipe heat-treatment-finishing-treatment continuous facility includes: a heat treatment apparatus; a steel pipe inspection apparatus which performs a test for a surface defect and/or an inner defect of the seamless steel pipe, the steel pipe inspection apparatus being disposed downstream of the heat treatment apparatus; a main transfer mechanism which forms a main transfer path MT for transferring the seamless steel pipe, discharged from the heat treatment apparatus, to the steel pipe inspection apparatus disposed downstream of the heat treatment apparatus; and a first forced steel pipe-temperature reduction apparatus which forcibly reduces a temperature of the seamless steel pipe on the main transfer path MT, the first forced steel pipe-temperature reduction apparatus being disposed on the main transfer path MT at a position downstream of the heat treatment apparatus and upstream of the steel pipe inspection apparatus.

Abstract: A method for producing a component may include one or more of the following: providing and/or producing a profiled structural part, the structural part including a predetermined profile along its length; heat treating the profiled structural part; and press hardening the profiled structural part in a press-hardening tool. The profiled structural part in the press-hardening tool may be cooled in an interior thereof by circulating air, where during cooling of the profiled structural part in the press-hardening tool, different material properties are specifically set in at least two regions of the profiled structural part.

Abstract: The present invention deals with alloyed steels having yield strength of at least 862 MPa (125 Ksi) and exhibiting outstanding hardness and toughness behavior, especially under stringent conditions which may be subjected to frost-heave and thaw settlement cycles, namely at subzero temperatures. The invention also relates to a seamless pipe comprising said steel and a method of production of said pipe thereof.

Abstract: A process for preparing a multi-thickness welded steel vehicle rail, the process comprises the steps of: (a) forming a first tube having a first outer diameter, an inner diameter and a first wall thickness; (b) forming a second tube having the first outer diameter, a second inner diameter and a second wall thickness different than the first wall thickness; (c) swaging a first end of the first tube to a second outer diameter less than the second inner diameter of the second tube; (d) inserting the swaged first end of the first tube into an end of the second tube to form a joint; (e) welding the first tube and the second tube together to form a weld at the joint to form a tube blank with a heat affected zone of lower metal strength in the area of the weld; (f) preheating the tube blank to create a common crystalline microstructure along a length of the tube blank; (g) introducing the tube blank into a blow molding tool having inner molding walls; (h) molding the tube blank at an elevated temperature by expandin

Abstract: The present invention discloses an annular cooling device for large-scale cylindrical shell, which comprises a plurality of inner jet devices and outer jet devices; the inner jet devices are arranged inside the cylindrical shell along the inner periphery; the outer jet devices are arranged outside the cylindrical shell along the outer periphery; each inner jet device and each outer jet device are oppositely arranged; the inner jet devices are used for spraying cooling medium to the inner wall of the cylindrical shell; the outer jet devices are used for spraying the cooling medium to the outer wall of the cylindrical shell; and the spray ranges of each inner jet device and each outer jet device in the axial direction of the cylindrical shell are both greater than the length of the cylindrical shell.

Abstract: A method quenches a steel pipe and an apparatus quenches a steel pipe by which a steel pipe having excellent and uniform quality can be acquired by applying uniform rapid cooling to the steel pipe in a longitudinal direction as well as in a circumferential direction of the steel pipe using a simple unit. Movements of a heated steel pipe in a direction parallel to and in a direction perpendicular to a pipe axis of the steel pipe are stopped, and cooling water is jetted onto an outer surface of the steel pipe from four or more spray nozzles arranged spirally outside the steel pipe while rotating the steel pipe about the pipe axis.

Abstract: A method is provided for preventing cracking along the surface at the inner hole of a hollow shaft during water quenching, including: a step of water-quenching the inner hole of the shaft placed horizontally, while the outer circle of the shaft is in a state of air cooling, in which the cooling time of the outer circle is selected to be not lower than its Ar1 temperature so as to induce a compressive stress in the surface layer of the inner hole; and a step of water-quenching the outer circle and the inner hole of the shaft simultaneously, moreover, the quenching intensity of the inner hole is gradually reduced to cause a temperature rise in the surface layer of the inner hole to allow martensite in the surface layer to undergo self-tempering, which prevents the formation of quenching cracks along the surface of the inner hole.

Abstract: A method for manufacturing a quenched molding according to the present disclosure is a method including a first heat treatment process of heating a blanked steel material to a temperature higher than its Ac3 transformation point to perform austenite transformation, and then cooling to induce martensite transformation or bainite transformation, and a second heat treatment process of heating the steel material that has undergone the first heat treatment process to a temperature higher than the Ac3 transformation point to perform austenite transformation, and then cooling to induce martensite transformation. After the steel material has been heated to a temperature higher than the Ac3 transformation point in at least one process from out of the first heat treatment process or the second heat treatment process, molding is completed at a temperature higher than an Ar3 transformation point.

Abstract: The invention relates to a process for producing a component having improved elongation at break properties, in which a component is firstly produced, preferably in a hot forming or press curing process, and the component is heat treated after hot forming and/or press curing, where the heat treatment temperature T and the heat treatment time t essentially satisfy the numerical relationship T?900·t?0.087, where the heat treatment temperature T is in ° C. and the heat treatment time t is in seconds. The invention also relates to a component, in particular an automobile body component or the chassis of a motor vehicle, which has been produced by such a process. The invention further relates to the use of such a component as part of an automobile body or a chassis of a motor vehicle.

Abstract: A method for manufacturing a heavy wall steel pipe includes a cooling step in which a steel pipe, with a wall thickness of ½ inch or more, that has been heated to the gamma range is dipped in water while supporting and rotating the steel pipe about the axis of pipe, an axial stream which is a water flow in the direction of axis of pipe is applied to the inside surface of the steel pipe under rotation in the water, and an impinging stream which is a water flow impinging on the outer surface of the pipe is applied to the outer surface of the steel pipe under rotation in the water.

Abstract: A method of fabricating a martensitic stainless steel including: 1) heating steel to a temperature higher than austenizing temperature of the steel, then quenching the steel until a hottest portion of the steel is at a temperature less than or equal to a maximum temperature, and greater than or equal to a minimum temperature, a cooling rate being sufficiently fast for austenite not to transform into a ferrito-perlitic structure; 2) performing a first anneal followed by cooling until the hottest portion of the steel is at a temperature less than or equal to the maximum temperature and greater than or equal to the minimum temperature; 3) performing a second anneal followed by cooling to ambient temperature; and at the end of each of 1) and 2), performing: ?) as soon as temperature of the hottest portion of the steel reaches the maximum temperature, immediately heating the steel once more.

Abstract: A hollow seamless pipe for a high-strength spring in the present invention includes a steel material in which chemical component compositions are properly adjusted, wherein a depth of a whole decarburized layer in an inner surface layer part is 100 ?m or less, a depth of a flaw which is present in an inner surface is 40 ?m or less, a width of the flaw is 60 ?m or less, and a number density of a carbide which has a circle equivalent diameter of 500 nm or more and is present in the inner surface layer part is 1.8×10?2 particles/?m2 or less.

Abstract: A method of manufacturing a plurality of housings. The method may include maintaining an inventory of initial products. Each of the initial products may include a central hollow body extending along a longitudinal axis and monolithically formed with at least one of a suction passage and a discharge passage. Each of the products may have a same initial length. The method may further include receiving a first order for a first housing having a first length and machining a first product to the first length to form the first housing. Also, the method may include receiving a second order for a second housing having a second length and machining a second product to the second length to form the second housing. The first length and the second length may be different.

Abstract: The present invention relates to a process for producing a pipe, particularly for supplying fuel to an engine, comprising the steps of: prearranging a pipe made of stainless steel (1), executing a hot-pressing operation at at least one end (3) of the pipe (1); and subjecting the at least one end (3) of the pipe (1) to heat treatment, followed by cooling.

Abstract: A high-strength welded steel pipe is obtained by welding a seam weld portion of a steel plate that are formed in a pipe shape. In the high-strength welded steel pipe, a base metal of the steel plate includes, by mass %, C: 0.010% to 0.080%, Si: 0.01% to 0.50%, Mn: 0.50% to 2.00%, S: 0.0001% to 0.0050%, Ti: 0.003% to 0.030%, Mo: 0.05% to 1.00%, B: 0.0003% to 0.0100%, O: 0.0001% to 0.0080%, N: 0.006% to 0.0118%, P: limited to 0.050% or less, Al: limited to 0.008% or less, and the balance of Fe and inevitable impurities, Ceq is 0.30 to 0.53, Pcm is 0.10 to 0.20, [N]?[Ti]/3.4 is less than 0.003, the average grain size of the prior ? grains in heat affected zones in the steel plate is 250 ?m or less, and the prior ? grains include bainite and intragranular bainite.

Abstract: In a method for heat treating a metal tube or pipe for a nuclear power plant, the tube or pipe being accommodated in a batch-type vacuum heat treatment furnace, when the tube or pipe is laid down on and is subjected to heat treatment on a plurality of metal cross beams arranged along a longitudinal direction of the tube or pipe, it is possible to suppress scratches to be formed on the outer surface of the tube or pipe and attributable to heat treatment, and to reduce the discoloration on the outer surface of the tube or pipe by holding the tube or pipe and the metal cross beams in indirect contact with each other by virtue of a heat resistant fabric having a thickness of 0.1 to 1.2 mm interposed in between.

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: In a method for heat treating a metal tube or pipe for a nuclear power plant, the tube or pipe being accommodated in a batch-type vacuum heat treatment furnace, when the tube or pipe is laid down on and is subjected to heat treatment on a plurality of metal cross beams arranged along a longitudinal direction of the tube or pipe, it is possible to suppress scratches to be formed on the outer surface of the tube or pipe and attributable to heat treatment, and to reduce the discoloration on the outer surface of the tube or pipe by holding the tube or pipe and the metal cross beams in indirect contact with each other by virtue of a heat resistant fabric having a thickness of 0.1 to 1.2 mm interposed in between.

Abstract: A method of production of high-strength hollow bodies from multiphase martensitic steels includes a heating process, a forming process and a cooling process. A heating device heats hollow steel stock to the austenitic temperature of the material from which the stock is made. The stock is then converted by deformation in a forming device into a hollow body having the final shape. A cooling device thereafter cools the hollow body such that the material with the original austenite microstructure refined by deformation during the forming process cools to a temperature at which incomplete transformation of austenite to martensite occurs. The retained austenite stabilization is performed in an annealing device by diffusion-based carbon partitioning within the material from which the hollow body is made. The hollow body is cooled in a cooling device to ambient temperature after stabilization.

Abstract: A steel pipe with excellent expandability, comprising, by mass %, C: 0.1 to 0.45%, Si: 0.3 to 3.5%, Mn: 0.5 to 5%, P: less than or equal to 0.03%, S: less than or equal to 0.01%, soluble Al: 0.01 to 0.8% (more than or equal to 0.1% in case Si content is less than 1.5%), N: less than or equal to 0.05%, O: less than or equal to 0.01%, and balance being Fe and impurities, having a mixed microstructure comprising ferrite and one or more selected from fine pearlite, bainite and martensite, and having a tensile strength of more than or equal to 600 MPa and a uniform elongation satisfying following formula (1). This steel pipe, having the above described chemical composition, can be obtained, for example, by being heated at temperatures from 700 to 790° C., then being forced-cooled down to a temperature of lower than or equal to 100° C. with the cooling rate of greater than or equal to 100° C./min at the temperature from 700 to 500° C. u-el?28?0.

Abstract: A steel pipe with a wall thickness over 30 mm is subjected to heat treatment of quenching and tempering using a temperature range of at least not less than 750° C. during the heating stage, makes it possible to obtain a heavy-wall seamless steel pipe having excellent toughness by resulting grain refinement. Quenching is by performing water cooling after heating the steel pipe to a temperature in the range of not less than 900° C. to not more than 1000° C. by using, as a heating means, induction heating at a frequency of not more than 200 Hz. Tempering is performed at a temperature in the range of not less than 500° C. to not more than 750° C. Preferably, after the heating by induction heating, a soaking treatment is performed in the temperature range of not less than 900° C. to not more than 1000° C. for 10 minutes or less followed by water cooling.

Abstract: Embodiments of the present disclosure are direct to a low-carbon chromium steel, and methods for manufacturing said steel, having a low vanadium concentration. In some embodiments, the steel can have high corrosion resistance while retaining adequate strength and toughness. The steel can be manufactured through an austenitization process, followed by quenching at a controlled cooling rate, and tempering to form about 5 to 10% bainite, while limiting formation of chromium rich carbides.

Abstract: The present invention provides a steel material for automobile chassis parts which has high fatigue characteristics, does not require much cost for heat treatment, and further is superior in shapeability and a method of production of automobile chassis parts using this steel material, that is, one being a steel material to which Nb and Mo have been compositely added and having a difference 50 to 150 points between a Vicker's hardness of the center of plate thickness and a maximum value of Vicker's hardness within 0.5 mm from the surface after bending by a bending R of the plate outer surface of 2 to 5 times the plate thickness. The surface is high in hardness and the center part is low in hardness, so the fatigue characteristics and shapeability are superior. Note that if annealing under conditions giving a tempering parameter ? defined by ?=T(20+log(t)) of 14000 to 19000 (where T is the absolute temperature, t is the time (h), and the temperature rise is 660° C.

Abstract: A method for producing a high fatigue life quenched/tempered steel pipe comprises a quenching treatment of keeping an unquenched starting steel pipe having a composition that comprises, % by mass, C: 0.1 to 0.4%, Si: 0.5 to 1.5%, Mn: 0.3 to 2%, P: at most 0.02%, S: at most 0.01%, Cr: 0.1 to 2%, Ti: 0.01 to 0.1%, Nb: 0.01 to 0.1%, Al: at most 0.1%, B: 0.0005 to 0.01%, and N: at most 0.01%, with a balance of Fe and inevitable impurities, at 900 to 1100° C. for 10 to 60 seconds and then rapidly cooling it. The cooled pipe is subjected to a tempering treatment of keeping the pipe at 280 to 380° C. for 10 to 60 minutes.

Abstract: A heavy wall and high strength seamless steel pipe having high sour resistance is provided. In particular, a quenching and tempering treatment is conducted to adjust the yield strength to be higher than 450 MPa and adjust the Vickers hardness HV5 that can be measured at an outermost side or an innermost side of the pipe under a 5 kgf load (test load: 49 N) to be 250 HV5 or less.

Abstract: Embodiments of the present disclosure comprise carbon steels and methods of manufacture. In one embodiment, quenching and tempering procedure is performed in which a selected steel composition is formed and heat treated to yield a slightly tempered microstructure having a fine carbide distribution. In another embodiment, a double austenizing procedure is disclosed in which a selected steel composition is formed and subjected to heat treatment to refine the steel microstructure. In one embodiment, the heat treatment may comprise austenizing and quenching the formed steel composition a selected number of times (e.g., 2) prior to tempering. In another embodiment, the heat treatment may comprise subjecting the formed steel composition to austenizing, quenching, and tempering a selected number of times (e.g., 2). Steel products formed from embodiments of the steel composition in this manner (e.g., seamless tubular bars and pipes) will possess high yield strength, e.g.

Abstract: There is provided a high-strength steel tube having excellent chemical conversion treatability and excellent formability and a method for manufacturing the high-strength steel tube. More specifically, in processing a mother steel sheet containing, on the basis of mass percent, 0.05% or more C, more than 0.7% Si, and 0.8% or more Mn into a pipe shape, the sum total of absolute circumferential surface strains each applied in individual process steps of the processing is 5% or more as nominal strain. A welded steel tube thus manufactured using a steel sheet even containing more than 0.7% Si can have excellent chemical conversion treatability without mechanical grinding or chemical pickling treatment.

Abstract: A high-strength steel machined product giving excellent hardenability has a metal microstructure with excellent balance of strength and toughness and high stability of retained austenite. The product is composed of an ultra-high low-alloy TRIP steel having a metal microstructure which contains an appropriate quantity of two or more of Cr, Mo, and Ni, and an appropriate quantity of one or more of Nb, Ti, and V, and having an appropriate value of carbon equivalent; the metal microstructure has a mother-phase structure composed mainly of lathy bainitic ferrite with a small amount of granular bainitic ferrite and polygonal ferrite, and has a secondary-phase structure composed of fine retained austenite and martensite.

Abstract: A seamless steel tube for an airbag accumulator which can be manufactured by heat treatment of normalizing without quenching and tempering and which has a tensile strength of at least 850 MPa and resistance to bursting at ?20° C. has a stee; composition comprising, in mass %, C: 0.08-0.20%, Si: 0.1-1.0%, Mn: 0.6-2.0%, P: at most 0.025%, S: at most 0.010%, Cr: 0.05-1.0%, Mo: 0.05-1.0%, Al: 0.002-0.10%, at least one of Ca: 0.0003-0.01%, Mg: 0.0003-0.01%, and REM (rare earth metals): 0.0003-0.01%, at least one of Ti: 0.002-0.1% and Nb: 0.002-0.1%, with Ceq which is defined by the following Equation (1) being in the range of 0.45-0.63, with the metallurgical structure being a mixed structure of ferrite+bainite: Ceq=C+Si/24+Mn/6+(Cr+Mo)/5+(Ni+Cu)/15??(1) wherein the symbol for each element in Equation (1) indicates the number expressing the mass percent of the element.

Abstract: A method of producing a seamless, tubular product includes centrifugally casting a corrosion resistant alloy into a tubular workpiece having an inner diameter and an outer diameter. The method then removes material from the inner diameter of the workpiece and subjects the workpiece to at least about a 25% wall reduction at a temperature below a recrystallization temperature of the workpiece using a metal forming process. The metal forming process includes radial forging, rolling, pilgering, and/or flowforming.

Abstract: In quenching, where a heated steel pipe (2) is immersed in a water bath (3) in parallel with water surface for cooling a pipe outer surface, and cooling water is injected from an axial center nozzle (8) into one end of pipe for cooling a pipe inner surface, thereby rapidly cooling the entire pipe surface, reduction of strength difference along a length of the quenched pipe becomes possible by moving the nozzle (8) following the motion of the pipe axis (2), and starting injecting the water from the nozzle (8) so as for the water to reach the other pipe end at the time of the immersion of the entire circumference of the pipe outer surface. An opening (3a) preferably faces the nozzle (8) to remove the water, and the flow velocity is preferably set to 23 m/sec or more for better water flow inside the pipe (2).

Abstract: Embodiments of the present disclosure comprise carbon steels and methods of manufacture. In one embodiment, a double austenizing procedure is disclosed in which a selected steel composition is formed and subjected to heat treatment to refine the steel microstructure. In one embodiment, the heat treatment may comprise austenizing and quenching the formed steel composition a selected number of times (e.g., 2) prior to tempering. In another embodiment, the heat treatment may comprise subjecting the formed steel composition to austenizing, quenching, and tempering a selected number of times (e.g., 2). Steel products formed from embodiments of the steel composition in this manner (e.g., seamless tubular bars and pipes) will possess high yield strength, at least about 175 ksi (about 1200 MPa) while maintaining good toughness.

Abstract: A treatment of a heater tube intended to be used in a pressurizer of the primary cooling system of a nuclear reactor. In particular, the heater tube comprises a heater housed in a substantially cylindrical sheath. The material of which this sheath is made is a work-hardened austenitic stainless steel. In particular, the external surface of the sheath is liable to undergo a stress corrosion during use of the heatertube. The method includes a heat treatment step, preferably using induction heating, in which the external surface of the sheath is heat-treated so as to recrystallize the material of the sheath at least on the surface thereof.

Abstract: A method of manufacturing a 13Cr steel pipe which satisfies a hardness (HRC) of at most 22 with 13Cr grade L80 of American Petroleum Institute (API) standards, which is an indicator of a high strength, high yield ratio, and good corrosion resistance, is provided. A steel billet having a chemical composition comprising, in mass percent, C: 0.15-0.21%, Si: 0.16-1.0%, Mn: 0.35-1.0%, Cr: 10.5-14.0%, P: at most 0.020%, S: at most 0.0050%, Al: 0.025-0.050%, and a remainder of Fe and impurities is subjected to hot working with a finishing temperature of 800-960° C. to form a mother pipe, which is immediately quenched at a cooling rate of at least air cooling and then tempered by heating.

Abstract: A high strength bainitic steel and a process for producing seamless pipes for OCTG applications are described. In particular, the advantages ensuing to the steel of the invention are the improvement in strength-toughness over tempered martensitic steels, and a simplified thermal treatment. Quenching is not necessary and by avoiding the quenching treatment the microstructure results far more homogeneous, which allows thick walled tubes to be produced. For the same steel composition, in comparison to conventional tempered martensitic structures, a better combination of strength and toughness can be achieved, in particular by tempering as rolled carbide-free bainitic structures.

Abstract: A heat treatment method of heat-treating a steel tube provides the steel tube with satisfactory workability and high pressure resistance capable of coping with a recent increasing trend of pressure dealt with by a recent common rail type fuel injection system. A steel tube of a desired size is formed by drawing a material of a steel containing at least vanadium. The steel tube is processed for normalizing by holding the steel tube at high temperatures between 950 and 1000° C. for a predetermined time and slowly cooling the steel tube at a predetermined cooling rate. Then, the steel tube is processed for tempering by heating the steel tube at a temperature between 500 and 700° C. and cooling the steel tube to an ordinary temperature at an optional cooling rate.

Abstract: The invention relates to a method for transforming steel blanks. The invention in particular relates to a method for transforming a steel blank comprising kneading in order to obtain very good mechanical properties. The obtained products may notably be used for forming a pressure device component.

Abstract: A method for casting medium carbon, B/Ti steel product using compact strip processing or thin slab casting. The method can include providing a steel composition including boron and titanium and casting the steel composition into a slab having a thickness between about 25 and 150 mm. The slab can have a cast composition including about 0.23 to 0.30 wt. % carbon, about 0.0010 to 0.0050 wt. % boron, about 0.010 to 0.050 wt. % titanium, about 1.15 to 1.50 wt. % manganese, less than 0.35 wt. % silicon and a Ti/N ratio greater than 2.9. The amount of each element is provided based upon the total weight of the steel composition. The steel slab can be free from cracks and significant defects. Furthermore, the steel slab can be used for electric resistance welded (ERW) products.

Abstract: To provide a technique suitable for elevating strength and toughness of a thin low-carbon steel. By performing rapid heating and rapid cooling to a thin low-carbon steel which is an ordinary steel with a thickness of 1.2 mm or less, a steel where a microstructure becomes a duplex grain size structure mixed with crystal grains having different grain diameters, which is not homogeneous, preferably, hard phase structures are contained in addition to the duplex grain size structure is obtained, and a high-strength and high-toughness thin low-carbon steel is obtained. Further, by performing a heat treatment process involving rapid heating and rapid cooling multiple times, a duplex grain size structure of crystal grains with smaller grain diameters or a hard phase structure contained therein is obtained, so that a thin low-carbon steel with higher strength and higher toughness is obtained.

Abstract: Use of a steel alloy for well pipes of perforating units for perforation of borehole casings, with the steel alloy comprised, in mass-%, of Carbon (C) 0.12-0.25, Manganese (Mn) 0.5-2.0, Silicon (Si) 0.1-0.5, Nitrogen (N) 0.006-0.015, Sulfur (S) <0.005, Chromium (Cr) 0.1-1.5, Molybdenum (Mo), <0.3, Nickel (Ni) <1.0, Vanadium (V) <0.25, Niobium (Nb) 0.010-0.15, Titanium (Ti) 0.02-0.06, Boron (B) 0.001-0.006, Calcium (Ca) <0.0025, and iron as well as impurities resulting from smelting as remainder, wherein the steel alloy is heated at a heating rate of 1-100 K/s to an austenitizing temperature between 10 to 50° C. above its transformation temperature Ac3, and held at this austenitizing temperature between 0.

Abstract: Provided is a steel pipe suitable for machine structure members that are required to be lightweight, of which the strength is increased and the fatigue life is prolonged with preventing the increase in the material cost and the production cost. The steel pipe is a high fatigue life quenched/tempered steel pipe having a composition comprising, % by mass, C: 0.1 to 0.4%, Si: 0.5 to 1.5%, Mn: 0.3 to 2%, P: at most 0.02%, S: at most 0.01%, Cr: 0.1 to 2%, Ti: 0.01 to 0.1%, Nb: 0.01 to 0.1%, Al: at most 0.1%, B: 0.0005 to 0.01%, N: at most 0.01%, and optionally at least one of Ni: at most 0.5%, Ca: at most 0.02%, Mo: at most 0.5% and V: at most 0.5%, with a balance of Fe and inevitable impurities, in which the mean grain size of the precipitated carbides is at most 0.5 ?m and of which the hardness in the center part of the wall thickness in the cross section perpendicular to the longitudinal direction of the steel pipe is at least 400 HV.

Abstract: A method for improving a residual stress in a pipe includes improving the residual stress in the inner surface to the compressive direction by rapid cooling of the inner surface after heating of the pipe. The heating is to heat a vicinity of a welded part of the pipe from the outer surface to raise the temperature to a construction temperature. The rapid cooling is to rapidly cool the inner surface in the vicinity of the welded part by supplying cooling water into the pipe. The heating and the rapid cooling are repeated twice or more. A method for construction management includes determining whether construction has been executed properly based on a maximum value of a lowering rate of an outer surface temperature of the pipe when the cooling water is supplied for the rapid cooling of the inner surface and a thickness of the pipe in a measuring position of the outer surface temperature.

Abstract: The present invention pertains to steel with high mechanical resistance at room temperature and up to 130° C., good toughness and good corrosion resistance in the metal base as well as good resistance to cracking in the heat affected zones (HAZ) once the tubing is welded together, and more specifically to heavy gauge seamless steel tubing with high mechanical resistance, good toughness and good corrosion resistance called catenary conduit. The advantages of the present invention with respect to those of an the state of technology reside in providing a chemical composition for steel used to manufacture heavy gauge seamless steel tubing with high mechanical resistance, good toughness, good fissure resistance in the HAZ and good corrosion resistance and a process for manufacturing this product. These advantages are obtained by using a composition made up basically of Fe and a specific chemical composition.

Abstract: A steel pipe with excellent expandability, comprising, by mass %, C: 0.1 to 0.45%, Si: 0.3 to 3.5%, Mn: 0.5 to 5%, P: less than or equal to 0.03%, S: less than or equal to 0.01%, soluble Al: 0.01 to 0.8% (more than or equal to 0.1% in case Si content is less than 1.5%), N: less than or equal to 0.05%, O: less than or equal to 0.01%, and balance being Fe and impurities, having a mixed microstructure comprising ferrite and one or more selected from fine pearlite, bainite and martensite, and having a tensile strength of more than or equal to 600 MPa and a uniform elongation satisfying following formula (1). This steel pipe, having the above described chemical composition, can be obtained, for example, by being heated at temperatures from 700 to 790° C., then being forced-cooled down to a temperature of lower than or equal to 100° C. with the cooling rate of greater than or equal to 100° C./min at the temperature from 700 to 500° C. u-el?28?0.

Abstract: A seamless, rotationally symmetrical hollow blank formed by a non-cutting operation from a deformable permanently magnetic alloy is provided, said alloy consisting essentially of 5.0 to 20.0 percent by weight cobalt, 20.0 to 35.0 percent by weight chromium, for the remainder iron and impurities caused by melting and/or by chance. The seamless hollow body is suitable in particular for use in hysteresis clutches, hysteresis brakes, and position measuring devices. Furthermore, non-cutting shaping processes for producing the seamless rotationally symmetrical hollow body are provided, with roller spinning being preferred.

Abstract: In a method of manufacturing a hollow stabilizer, a pipe compressing step of compressing an electroseamed pipe in a temperature range of a hot state or a warm state so as to make a rate of a thickness with respect to an outer diameter between 18 and 35% is performed, and a forming step of forming the compressed electroseamed pipe in a stabilizer shape in a cold state is executed. Next, a step of applying a heat treatment to a half-finished stabilizer is performed, a shot peening step of impacting a shot on the half-finished stabilizer is performed, and a step of coating the half-finished stabilizer is performed.

Abstract: A seamless steel pipe for line pipe having high strength and stable toughness and having resistance to sulfide corrosion cracking at low temperatures to room temperature is provided. A seamless steel pipe according to the present invention has a chemical composition comprising, in mass percent, C: 0.03-0.08%, Si: 0.05-0.5%, Mn: 1.0-3.0%, Mo: greater than 0.4% to 1.2%, Al: 0.005-0.100%, Ca: 0.001-0.005%, a remainder of Fe and impurities including N, P, S, O, and Cu, with the impurities containing at most 0.01% of N, at most 0.05% of P, at most 0.01% of S, at most 0.01% of O, and at most 0.1% of Cu, and having a microstructure comprising a bainitic-martensitic dual phase structure.

Abstract: An oil country tubular good for expansion according to the invention is expanded in a well. The oil country tubular good for expansion has a composition containing, in percentage by mass, 0.05% to 0.08% C, at most 0.50% Si, 0.80% to 1.30% Mn, at most 0.030% P, at most 0.020% S, 0.08% to 0.50% Cr, at most 0.01% N, 0.005% to 0.06% Al, at most 0.05% Ti, at most 0.50% Cu, and at most 0.50% Ni, and the balance consisting of Fe and impurities, and a structure having a ferrite ratio of at least 80%. The oil country tubular good for expansion has a yield strength in the range from 276 MPa to 379 MPa and a uniform elongation of at least 16%. Therefore, the oil country tubular good according to the invention has a high pipe expansion characteristic.

Abstract: The method for manufacturing a martensitic stainless pipe includes heating the steel pipe until the external surface temperature thereof reaches a predetermined temperature not lower than A3 transformation point+20° C. and not higher than 980° C. The heated steel pipe is first water cooled until the external surface temperature thereof reaches a predetermined temperature not lower than 350° C. The water cooled steel pipe is air cooled until the external surface temperature thereof reaches a predetermined temperature not higher than 250° C. The air cooled steel pipe is either water or air cooled until the external surface temperature thereof reaches normal temperature. The cooling rate of the steel pipe in the first cooling step is determined according to the wall thickness of the steel pipe so that the amount of heat recuperation for the external surface temperature of the steel pipe in the second cooling step is not higher than 50° C.

Abstract: The present invention describes a seamless steel tube for work-over risers comprising in weight percent, carbon 0.23-0.29, manganese 0.45-0.65, silicon 0.15-0.35, chromium 0.90-1.20, molybdenum 0.70-0.90, nickel 0.20 max, nitrogen 0.010 max, boron 0.0010-0.0030, aluminum 0.010-0.045, sulfur 0.005 max, phosphorus 0.015 max, titanium 0.005-0.030, niobium 0.020-0.035, copper 0.15 max, arsenic 0.020 max, calcium 0.0040 max, tin 0.020 max, hydrogen 2.4 ppm max, the rest are iron and inevitable impurities, consisting of a geometry in which ends of the tube have an increased wall thickness and outer diameter and having a yield strength of at least of 620 MPa (90 ksi) throughout the whole length of a tube body and in tube ends. The present invention also describes methods for manufacturing a seamless steel tube for work-over risers having a yield strength at least of 620 MPa (90 ksi) both in a tube body and in tube ends.