Class / Patent application number | Description | Number of patent applications / Date published |
148590000 | Pipe or tube | 52 |
20090183805 | Cooling method of a steel pipe - A method of cooling a steel pipe which can effectively suppress quenching-induced bending which occurs when quenching a thin-walled steel pipe with a wall thickness/outer diameter ratio of at most 0.07 without decreasing the manufacturing efficiency of the steel pipe comprises cooling the inner surface of the steel pipe by spraying cooling water into the interior of a horizontally-disposed steel pipe | 07-23-2009 |
20100043926 | METHOD FOR PREVENTING CARBON STEEL FROM INTERGRANULAR CRACKING - A method for preventing carbon steel from intergranular cracking utilizing a reducing gas instead of nitrogen gas for a heat treatment of feeder pipes for a pressurized heavy water reactor (PHWR) nuclear power plant. This heat treatment protects carbon from oxidation to prevent the formation of decarburized layers so that the feeder pipes can be prevented from intergranular cracking. In addition, intergranular segregation of impurities is inhibited and intergranular strength of the carbon steel is enhanced. Therefore, no intergranular cracking occurs despite the concentration of stress. | 02-25-2010 |
20100051143 | Case Hardening Steel Tube Having Improved Workability and a Process for its Manufacture - A case hardening steel tube which has a hardness of 72-80 HRB and which gives a carburized layer with a high strength and high wear resistance and adequate resistance to impact fracture when it is formed into a final product by working and subsequent carburizing and quenching under relatively mild conditions is manufactured by forming a tube from a steel having a steel composition comprising, in mass percent, C: 0.1-0.25%, Si: 0.2-0.4%, Mn: 0.3-0.9%, P: at most 0.02%, S: 0.001-0.15%, Cr: 0.5-0.9%, Mo: 0.15-1%, Al: 0.01-0.1%, B: 0.0005-0.009%, N: less than 0.006%, and a remainder essentially of Fe, then subjecting the resulting steel tube to normalizing by soaking at a temperature of 880-980° C. followed by cooling at a cooling rate of at most 70° C. per minute, carrying out cold working of the normalized steel tube, and then annealing the cold worked steel tube at a temperature of 700-820° C. | 03-04-2010 |
20100065166 | STEEL PIPE WITH EXCELLENT EXPANDABILITY AND METHOD FOR PRODUCING THE SAME - A steel pipe with excellent expandability, comprises, 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 has a tensile strength of more than or equal to 600 MPa and a uniform elongation satisfying the following formula u-el≧28−0.0075 TS, wherein u-el is uniform elongation (%) and TS is tensile strength (MPa). | 03-18-2010 |
20100193086 | METHOD FOR MANUFACTURING MARTENSITIC STAINLESS STEEL PIPE OR TUBE - 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. | 08-05-2010 |
20110186188 | STEEL PIPE WITH EXCELLENT EXPANDABILITY AND METHOD FOR PRODUCING THE SAME - 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). | 08-04-2011 |
20110259482 | Use of a Steel Alloy for Well Pipes for Perforation of Borehole Casings, and Well Pipe - 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 0.1 and 10 minutes and austenitized, subsequently quenched at a quenching rate of >50K/s, so as to adjust a martensite content of >95%, wherein the remainder is formed of lower bainite, wherein the structure is then tempered starting from room temperature between 1 and 25 minutes at temperatures between 280° C. and 700° C., and finally cooled in air or quenched in water to room temperature, wherein the steel has a tensile strength Rm ranging from 600 MPa to 1,350 MPa at transverse notch impact toughnesses in a range between 210 and 70 J/cm | 10-27-2011 |
20130160903 | METHOD FOR QUENCHING STEEL PIPE AND METHOD FOR PRODUCING STEEL PIPE USING THE SAME - In quenching, where a heated steel pipe ( | 06-27-2013 |
20140202600 | METHOD OF MAKING QUENCHED AND TEMPERED STEEL PIPE WITH HIGH FATIGUE LIFE - 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. | 07-24-2014 |
20140251512 | LOW-CARBON CHROMIUM STEEL HAVING REDUCED VANADIUM AND HIGH CORROSION RESISTANCE, AND METHODS OF MANUFACTURING - 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. | 09-11-2014 |
20160068921 | METHOD AND TOOL FOR HARDENING A HOLLOW PROFILE OF A STEEL WORKPIECE - Disclosed herein is a method and tool for hardening a hollow profile of a steel workpiece having an interior space. The method includes the steps of providing a workpiece having a hollow profile, heating the hollow profile, placing the hollow profile of the steel workpiece in a hardening tool, and cooling the hollow profile from the inside by way of a cooling core having an exterior shape that is complimentary to that of the structural shape of the interior space of the hollow profile. | 03-10-2016 |
20160097593 | CONVEYOR FURNACE - A conveyor furnace includes a muffle having an inlet opening and an outlet opening, with a heating device for heating a volume delimited by the muffle, and a closed conveyor belt manufactured at least partially from metal. The conveyor furnace includes another heating device which is arranged so that, during the operation of the conveyor furnace, the heating device heats a section of the conveyor belt extending outside of the muffle. | 04-07-2016 |
148591000 | Treating with specified agent (e.g., heat exchange agent, protective agent, decarburizing agent, denitriding agent, etc.) or vacuum | 1 |
20090090439 | COLD WORKING LUBRICANT AND COLD WORKING METHOD FOR STEEL PIPE - The present invention provides a lubricant comprising an alkali soap and a cold working method, in which the lubricant layer can be easily formed on the surface of a steel pipe prior to cold working the reduces the work load during cold working of the steel pipe, and whose layer can be easily removed by washing the surface of the steel pipe after cold working. After that, an alkali soap aqueous solution or aqueous pasty alkali soap is applied to the working surface of the steel pipe, cold working of the steel pipe is performed, and thereafter the alkali soap layer is removed by washing with water. The alkali soap aqueous solution or aqueous pasty alkali soap is preferably prepared within a vessel having an inner surface consisting of a non-metal material. | 04-09-2009 |
148592000 | Nine percent or more chromium(Cr) (e.g., stainless steel, etc.) | 12 |
20090101247 | Method for producing martensitic stainless steel pipe - A martensitic stainless steel pipe, which comprises specified quantities of C, Si, Mn, P, S, Cr, Ni, Al, N, Cu, Ti, V, Mo, Nb, B and Ca, and the balance being Fe and impurities, has satisfactory toughness at a high strength of 650 MPa or more by yield strength and also excellent hot workability. Therefore, it can be used as a high-strength martensitic stainless steel pipe for carbon dioxide gas corrosion resistant use, to be used in oil and/or gas well environments containing no hydrogen sulfide but carbon dioxide gas. This high-strength martensitic stainless steel pipe is an inexpensive martensitic stainless steel pipe, which does not require an addition of large quantities of expensive elements such as Ni and Mo, and moreover does not require the control of the content of P to a value less than 0.010% by mass. | 04-23-2009 |
20090272469 | STAINLESS-STEEL PIPE FOR OIL WELL AND PROCESS FOR PRODUCING THE SAME - A steel composition contains: 0.05% or less of C; 0.5% or less of Si; 0.20% to 1.80% of Mn; 0.03% or less of P; 0.005% or less of S; 14.0% to 18.0% of Cr; 5.0% to 8.0% of Ni; 1.5% to 3.5% of Mo; 0.5% to 3.5% of Cu; 0.05% or less of Al; 0.20% or less of V; 0.01% to 0.15% of N; and 0.006% or less of O on a mass basis, and satisfies the following expressions: Cr+0.65Ni+0.6Mo+0.55Cu−20C≧18.5 and Cr+Mo+0.3Si−43.5C−0.4Mn−Ni−0.3Cu−9N≦11 (where Cr, Ni, Mo, Cu, C, Si, Mn, and N represent their respective contents (mass %)). After such a steel pipe material is formed into a steel pipe, the steel pipe is quenched by cooling after heating to a temperature of the A | 11-05-2009 |
20090277543 | PRODUCTION SYSTEM OF WELDABLE AND STAINLESS TUBULAR STRUCTURES WITH HIGH MECHANICAL STRENGTH AND PRODUCT OBTAINED THEREFROM - A production system weldable and stainless tubular structures with high mechanical strength and related obtained product, particularly for making tubular elements in cold-drawn stainless steel, workable at different thicknesses and shapes, provided with high performances in terms of mechanical characteristics and weldability, for the construction of light and ultralight structural frames destined for a dynamic use. It comprises a creation step of a tip for making the end of the tube smaller, so that it can pass through the drawing equipment and be coupled for drawing, a step of annealing heat treatment for softening the material and making it deformable. The system provides a mechanical test for evaluating the mechanical characteristics of the material and a metallography for viewing the structure of the material and evaluating if it comes within pre-established parameters for the drawing and a chemical preparation of the surfaces, for lubricating the contact surfaces of the tube with the drawing equipment and for avoiding seizures during the drawing. The preceding steps are repeated until the desired thickness. A step of final heat treatment follows, for reforming the structure of the steel and for fixing the desired final characteristics. Finally, a step of straightening is carried out for make the drawn and furnace-treated tube rectilinear, and a step of passivation for inducing a compact oxide patina ensuring its resistance to corrosion. The cutting, control and packaging operations follow. | 11-12-2009 |
20100006190 | PROCESS FOR PRODUCING BEND PIPE FOR LINE PIPE AND BEND PIPE FOR LINE PIPE - A steel pipe is prepared, which contains, by mass, at most 0.009% C, at most 1.0% Mn, at most 1.0% Si, at most 0.04% P, at most 0.005% S, 0.01 to 0.2% Ti, 0.01 to 0.10% V, 0.001 to 0.1% Al, at most 0.1% N, 4.0 to 8.0% Ni, 9.0 to 15.0% Cr, and 1.5 to 7.0% Mo, the balance being Fe and impurities. The prepared steel pipe is bent into a bend pipe. The bend pipe is quenched at a quenching temperature lower than 950° C. The quenched bend pipe is tempered. Accordingly, the bend pipe in accordance with the present invention has excellent SSC resistance. | 01-14-2010 |
20100193087 | MARTENSITIC STAINLESS STEEL SEAMLESS PIPE FOR OIL COUNTRY TUBULAR GOODS AND METHOD FOR MANUFACTURING THE SAME - A seamless steel pipe for oil country tubular goods which simultaneously has a high strength of a 110 ksi grade of yield strength and a superior low temperature toughness and a method for manufacturing the same are provided. A quenching treatment is performed on a stainless steel seamless pipe having a composition which contains on a mass percent basis, less than 0.010% of C, 1.0% or less of Si, 0.1% to 2.0% of Mn, 0.020% or less of P, 0.010% or less of S, 0.10% or less of Al, 10% to 14% of Cr, 0.1% to 4.0% of Ni, 0.05% or less of N, and the balance being Fe and inevitable impurities in which after heating is performed to a heating temperature for quenching equivalent to or more than the Ac | 08-05-2010 |
20110024005 | Method for Producing Two-Phase Stainless Steel Pipe - A two-phase stainless steel pipe that has not only a corrosion resistance required for oil well pipes but at the same time has a targeted strength is produced, without excessively adding alloying components, by selecting cold drawing conditions. | 02-03-2011 |
20120031534 | METHOD FOR PRODUCING HIGH-STRENGTH Cr-Ni ALLOY SEAMLESS PIPE - A method for producing a high-strength Cr—Ni alloy seamless pipe comprising preparing an alloy billet with a chemical composition consisting, by mass %, of C: 0.05% or less, Si: 1.0% or less, Mn: less than 3.0%, P: 0.005% or less, S: 0.005% or less, Cu: 0.01 to 4.0%, Ni: 25% or more and less than 35%, Cr: 20 to 30%, Mo: 0.01% or more and less than 4.0%, N: 0.10 to 0.30%, Al: 0.03 to 0.30%, O (oxygen): 0.01% or less, REM (rare earth metal): 0.01 to 0.20%, and the balance being Fe and impurities, and satisfying the formula N×P/REM≦0.10, wherein P, N and REM represent the contents (mass %) of P, N and REM, respectively. The pipe is hot worked using cross roll piercing, solution heat treated, and cold worked. The pipe is excellent in hot workability, stress corrosion cracking and does not laminate during cross piercing. | 02-09-2012 |
20150315667 | HEAT TREATMENT EQUIPMENT LINE FOR SEAMLESS STEEL TUBE OR PIPE, AND METHOD OF MANUFACTURING HIGH STRENGTH STAINLESS STEEL TUBE OR PIPE - A method of manufacturing a high strength stainless steel tube or pipe includes using an online heat treatment equipment line for a seamless steel tube or pipe in which a heating furnace for quenching, equipment for quenching, and a tempering furnace are used in the lower process of a rolling line, arranging cooling facilities capable of cooling a heat treated steel tube or pipe to a temperature of 20° C. or lower between the equipment for quenching and the tempering furnace, and cooling the heat treated steel tube or pipe to a temperature of 20° C. or lower before a tempering treatment is performed. | 11-05-2015 |
20150354022 | STAINLESS STEEL SEAMLESS PIPE FOR OIL WELL USE AND METHOD FOR MANUFACTURING THE SAME (AS AMENDED) - A steel pipe is formed by performing pipe making of a raw material having a composition containing C: 0.05% or less, Si: 0.50% or less, Mn: 0.20% to 1.80%, P: 0.030% or less, S: 0.005% or less, Cr: 14.0% to 18.0%, Ni: 5.0% to 8.0%, Mo: 1.5% to 3.5%, Cu: 0.5% to 3.5%, Al: 0.10% or less, Nb: more than 0.20% and 0.50% or less, V: 0.20% or less, N: 0.15% or less, and O: 0.010% or less, on a percent by mass basis, wherein Cr+0.65Ni+0.6Mo+0.55Cu−20C≧18.5 and Cr+Mo+0.3Si−43.3C−0.4Mn−Ni−0.3Cu−9N≦11 are satisfied and subjecting the resulting steel pipe to a quenching treatment to heat to a temperature higher than or equal to the A | 12-10-2015 |
20160024625 | COILED TUBE WITH VARYING MECHANICAL PROPERTIES FOR SUPERIOR PERFORMANCE AND METHODS TO PRODUCE THE SAME BY A CONTINUOUS HEAT TREATMENT - Described herein are coiled tubes with improved and varying properties along the length that are produced by using a continuous and dynamic heat treatment process (CDHT). Coiled tubes can be uncoiled from a spool, subjected to a CDHT process, and coiled onto a spool. A CDHT process can produce a “composite” tube such that properties of the tube along the length of the tube are selectively varied. For example, the properties of the tube can be selectively tailored along the length of the tube for particular application for which the tube will be used. | 01-28-2016 |
20160047019 | METHOD OF MANUFACTURING SUPERIOR 13CR THICKENED DRILLROD - A method for manufacturing a superior 13Cr thickened drillrod comprises the following steps: firstly, thickening the ends of a steel tube with a composition so as to obtain a drillrod with thickened ends, the composition in percentage by weight being: C: 0.01-0.05%, Si≦0.5%, Mn: 0.2-1.0%, Cr: 12-14%, Mo: 1-3%, Ni: 4-6%, and a balance of Fe and inevitable impurities; after heating the tube as a whole to 950-1000° C., air cooling same and tempering same at 600-650° C.; and machining the two thickened ends respectively into an externally threaded drillrod coupler and an internally threaded drillrod coupler; wherein the tube end thickening is an external thickening, including three rounds of heating and three rounds of thickening, with at least one pass of deformation for each round, and the heating temperature being 1150-1200° C. for each round; and the upsetting pressure for the first round of external thickening is 180-220 bars, the upsetting pressure for the second round of external thickening is 180-220 bars, and the upsetting pressure for the third round of external thickening is 140-180 bars. The drillrod according to the present invention can be used not only as a drillrod but also as an oil tube, fulfilling requirements of the exploration operation of a CO | 02-18-2016 |
20180023158 | HIGH-STRENGTH HEAVY-WALLED STAINLESS STEEL SEAMLESS TUBE OR PIPE AND METHOD OF MANUFACTURING THE SAME | 01-25-2018 |
148593000 | With working | 27 |
20080216928 | Seamless steel pipe for line pipe and a method for its manufacture - 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. | 09-11-2008 |
20080257459 | Seamless steel pipe and manufacturing method thereof - The present invention relates to the following seamless steel pipes excellent in strength, toughness and weldability, particularly suitable for submarine flow lines, and a manufacturing method thereof. | 10-23-2008 |
20080283160 | Bent pipe and a method for its manufacture - A bent pipe corresponding to at least API X100 grade and having a base metal with high strength and toughness and a weld metal with high toughness is provided. A steel plate prepared by cooling after hot rolling at a cooling rate at the central portion in the plate thickness direction of at most 5° C. per second at 700-500° C. is formed into a bend mother pipe, which is then heated to 900-1100° C. and subjected to bending, then it is cooled to a temperature of at most 300° C. at a cooling rate in the central portion of the thickness direction of at least 5° C. per second at 700-500° C., after which it is tempered at 300-500° C. | 11-20-2008 |
20080283161 | High strength seamless steel pipe excellent in hydrogen-induced cracking resistance and its production method - The present invention relates to a high strength seamless steel pipe excellent in hydrogen-induced cracking resistance, characterized by consisting of, by mass %, C: 0.03-0.11%, Si: 0.05-0.5%, Mn: 0.8-1.6%, P: 0.025% or less, S: 0.003% or less, Ti: 0.002-0.017%, Al: 0.001-0.10%, Cr: 0.05-0.5%, Mo: 0.02-0.3%, V: 0.02-0.20%, Ca: 0.0005-0.005%, N: 0.008% or less and O (Oxygen): 0.004% or less, and the balance Fe and impurities, and also characterized in that the microstructure of the steel is bainite and/or martensite, ferrite is precipitated at grain boundaries and yield stress is 483 MPa or more. Further, to ensure high strength of the steel, the seamless steel pipe preferably contains, by mass %, at least one of Cu: 0.05-0.5% and Ni: 0.05-0.5%. To produce the above-mentioned steel pipe, it is desirable to limit a starting temperature of quenching after rolling, a cooling rate and a tempering temperature. By this configuration a seamless steel pipe having an yield stress of 483 MPa or more and excellent HIC resistance, which is suitable for a pipeline, can be provided. | 11-20-2008 |
20090000709 | Method for producing high chromium seamless pipe or tube - A billet containing, by mass %, 8.0 to 16.0% of Cr with a value represented by the formula of “Cr+4Si−(22C+0.5Mn+1.5Ni+30N)” of not more than 9.0%, wherein the symbols of the elements represent the contents, by mass %, of the elements in the steel, is heated by means of a heating furnace conditioned so as to have a soaking temperature of 1100 to 1300° C. and an in-furnace time (min) of not less than “0.5×Diameter of the billet (mm)”. Thereafter, by means of a centering machine capable of forming a center hole having a diameter of not less than “0.34×Diameter of the billet (mm)” at one end face of the said billet where piercing starts by punch of 60 to 110° punching angle, a center hole is formed at the said face of the billet, followed by piercing and rolling by an inclined roll type piercing mill of not more than 8.0% plug tip draft rate. The thus-produced high-Cr seamless pipe or tube has excellent internal surface properties with minimized internal surface defects. | 01-01-2009 |
20090032150 | Oil country tubular good for expansion in well and manufacturing method thereof - 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 | 02-05-2009 |
20090044883 | METHOD OF MAKING A SEAMLESS HOT-FINISHED STEEL PIPE, AND DEVICE FOR CARRYING OUT THE METHOD - In a method of making a seamless hot-finished steel pipe a billet heated to a shaping temperature is pierced by a first shaping to a thick-walled hollow ingot which subsequently undergoes a radial forging process using an internal tool inserted in the hollow ingot and at least two forging jaws of a forging machine. The forging jaws act on the outer surface area of the hollow ingot, wherein the hollow ingot is turned and axially advanced in a clocked manner in the idle stroke phase of the forging jaws. | 02-19-2009 |
20090114318 | Seamless steel pipe for line pipe and a process for its manufacture - A seamless steel pipe for line pipe having a high strength and good toughness and corrosion resistance even though having a thick wall has a chemical composition comprising, in mass percent, C: 0.02-0.08%, Si: at most 0.5%, Mn: 1.5-3.0%, Al: 0.001-0.10%, Mo: greater than 0.4% to 1.2%, N: 0.002-0.015%, Ca: 0.0002-0.007%, and a remainder of Fe and impurities, wherein the contents of the impurities are at most 0.03% for P, at most 0.005% for S, at most 0.005% for O and less than 0.0005% for B and wherein the value of Pcm calculated by the following Equation (1) is at least 0.185 and at most 0.250. The steel pipe has a microstructure which primarily comprises bainite and which has a length of cementite of at most 20 micrometers: | 05-07-2009 |
20090120541 | High-Strength Steel Plate, Method of Producing the Same, and High-Strength Steel Pipe - The present invention provides a high-strength steel plate having excellent resistance to cutting crack, excellent Charpy absorbed energy, excellent DWTT properties, a low yield ratio, and a tensile strength of 900 MPa or more, a method of producing the steel plate, and a high-strength steel pipe using the steel plate. As solving means, a steel plate contains, by % by mass, 0.03 to 0.12% of C, 0.01 to 0.5% of Si, 1.5 to 3% of Mn, 0.01 to 0.08% of Al, 0.01 to 0.08% of Nb, 0.005 to 0.025% of Ti, 0.001 to 0.01% of N, and at least one component of 0.01 to 2% of Cu, 0.01 to 3% of Ni, 0.01 to 1% of Cr, 0.01 to 1% of Mo, and 0.01 to 0.1% of V; wherein the contents of Ca, O, and S satisfy the equation below; the microstructure includes ferrite and a second hard phase, the area fraction of ferrite being 10 to 50%; cementite in the second phase has an average grin size of 0.5 μm or less; and the total amount of Nb and the like contained in carbides thereof present in steel is 10% or less of the total content in steel. | 05-14-2009 |
20090218014 | Method for Producing Duplex Stainless Steel Seamless Pipe - The present invention is to provide a method for producing duplex stainless steel seamless pipe in which a duplex stainless steel billet can be inhibited from generating an oxide scale on the surface thereof during heating and the generation of outer surface flaw can also be prevented. The billet is heated in the a heating furnace for 1.5 hours or more and 4.0 hours or less at a heating temperature of 1250° C. or more and 1320° C. or less while regulating the average concentration of sulfur dioxide (SO | 09-03-2009 |
20090277544 | HIGH-TENSILE STRENGTH WELDED STEEL TUBE FOR STRUCTURAL PARTS OF AUTOMOBILES AND METHOD OF PRODUCING THE SAME - A high-tensile strength welded steel tube has excellent formability and torsional fatigue endurance after being formed into cross-sectional shape and then stress-relief annealed. A steel material used has a composition which contains C, Si, Al, 1.01% to 1.99% Mn, 0.041% to 0.150% Ti, 0.017% to 0.150% Nb, P, S, N, and O such that the sum of the content of Ti and that of Nb is 0.08% or more, the content of each of C, Si, and Al being within an appropriate range, the content of each of P, S, N, and O being adjusted to a predetermined value or less. | 11-12-2009 |
20100037992 | METHOD FOR TRANSFORMING STEEL BLANKS - 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. | 02-18-2010 |
20100294401 | HIGH STRENGTH BAINITIC STEEL FOR OCTG APPLICATIONS - 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. | 11-25-2010 |
20110209802 | METHOD FOR PROCESSING STEEL TUBES AND THE LIKES - A method for processing a steel tube includes the following steps: a softening step, in which a tube-to-be-processed is heated so that material property of the tube-to-be-processed is softened; a cooling step, in which the heated tube-to-be-processed is cooled down to a normal temperature; a wall cutting step, in which the cooled tube-to-be-processed is subjected to cutting by lathing an end section thereof so as to reduce wall thickness of the tube-to-be-processed at the end section; and a shrinking step, in which the thickness reduced section of the wall lathed tube-to-be-processed is subjected to compression to have an inner bore thereof shrunk and thus reduced, whereby occupation of the inner bore of the shrunk tube-to-be-processed by the wall thickness of the tube-to-be-processed is reduced so as to obtain a possible maximum inside diameter of the inner bore and prevent the tube-to-be-processed from undesired deformation and breaking. | 09-01-2011 |
20110247733 | SEAMLESS STEEL PIPE AND METHOD FOR MANUFACTURING THE SAME - A seamless steel pipe of a low-alloy steel consisting, by mass %, of C: 0.10 to 0.20%, Si: 0.05 to 1.0%, Mn: 0.05 to 1.2%, Ni: 0.02 to 1.5%, Cr: 0.50 to 1.50%, Mo: 0.50 to 1.50%, Nb: 0.002 to 0.10%, Al: 0.005 to 0.10%, and either or both of Ti: 0.003 to 0.050% and V: 0.01 to 0.20%, the balance being Fe and impurities, the impurities containing 0.025% or less of P, 0.005% or less of S, 0.007% or less of N, and less than 0.0003% of B, wherein the tensile strength is 950 MPa or more and the yield strength is 850 MPa or more, and the Charpy absorbed energy at −40° C. is 60 J or more. This seamless steel pipe may further contain one or more of Cu: 0.02 to 1.0%, Ca: 0.0005 to 0.0050%, and Mg: 0.0005 to 0.0050%. The present invention also provides a method for manufacturing the above-described seamless steel pipe. | 10-13-2011 |
20110272067 | Method and Apparatus for Producing Steel Pipes Having Particular Properties - The invention relates to a method and to an apparatus for producing pipes made of steel. According to the invention, within a period of time of no more than 20 seconds after the last deformation at a temperature greater than 700° C., but less than 1050° C., during passage a cooling medium is applied with elevated pressure onto the outside circumference of the pipe over a length of greater than 400 times the pipe wall thickness in a quantity which during rapid cooling provides an equivalent cooling speed of greater than 1° C./second of the pipe wall over the pipe length to a temperature in the range of 500° C. to 250° C., whereupon further cooling of the pipe down to room temperature is carried out by exposure to air. | 11-10-2011 |
20120199255 | HIGH STRENGTH STEEL PIPES WITH EXCELLENT TOUGHNESS AT LOW TEMPERATURE AND SULFIDE STRESS CORROSION CRACKING RESISTANCE - Low-alloy steels and methods of manufacturing pipes having a wall thickness greater than or equal to about 8 mm and less than or equal to about 35 mm therefrom are provided. In one embodiment, a steel composition is processed that yields an average prior austenite grain size greater than about 15 or 20 μm and smaller than about 100 μm. A quenching sequence has been determined that yields a microstructure of greater than or equal to about 60% martensite by volume, and less than or equal to about 40% by volume lower bainite, without substantial formation of ferrite, upper bainite, or granular bainite. The yield strength of the quenched and tempered pipes may be greater than about 70 ksi, 80 ksi, or 90 ksi. The quenched and tempered pipes are suitable for 70 ksi, 80 ksi, and 90 ksi grades and resistant to sulfide stress corrosion cracking. | 08-09-2012 |
20120205016 | STEEL TUBE FOR AIRBAGS AND A PROCESS FOR MANUFACTURING SAME - A steel tube for an airbag which has a low alloy cost and a strength of at least 1000 MPa and vTrs100 of −80° C. or below and a process for its manufacture which can minimize the number of times that softening annealing treatment is performed in a cold drawing step are provided. Stable properties are obtained even when quench hardening is carried out by high frequency induction heating on a large scale. The steel tube has a steel composition which comprisise, in mass percent, C: 0.05-0.20%, Si: 0.10-0.50%, Mn: 0.10-1.00%, P: at most 0.025%, S: at most 0.005%, Al: 0.005-0.10%, Ca: 0.0005-0.0050%, Nb: 0.005-0.050%, Ti: 0.005-0.050%, Cu: 0.01-0.50%, Ni: 0.01-0.50%, Cr: 0.01-0.50%, B: 0.0005-0.0050%, N: 0.002-0.010%, and a remainder of Fe and unavoidable impurities. | 08-16-2012 |
20120211131 | HIGH STRENGTH STEEL HAVING GOOD TOUGHNESS - 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., at least about 165 ksi, while maintaining good toughness. | 08-23-2012 |
20120211132 | ULTRA HIGH STRENGTH STEEL HAVING GOOD TOUGHNESS - 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. | 08-23-2012 |
20120267014 | METHOD FOR MANUFACTURING SEAMLESS STEEL PIPE FOR LINE PIPE AND SEAMLESS STEEL PIPE FOR LINE PIPE - There is provided a method for manufacturing a seamless steel pipe for line pipe, capable of improving the toughness of the seamless steel pipe for line pipe. A round billet having a chemical composition, by mass percent, of C: 0.02 to 0.15%, Si: at most 0.5%, and Mn: 0.5 to 2.5%, the balance being Fe and impurities, is heated. The heated round billet is piercing-rolled to produce a hollow shell. The hollow shell is elongated and rolled and sized to produce a seamless steel pipe. The seamless steel pipe is water cooled, and the water cooling is stopped when the temperature of the seamless steel pipe reaches at most 450° C. The water-cooled seamless steel pipe is quenched, and the quenched seamless steel pipe is tempered. | 10-25-2012 |
20130056115 | AUTOMOBILE CHASSIS PART EXCELLENT IN LOW CYCLE FATIGUE CHARACTERISTICS AND METHOD OF PRODUCTION OF SAME - An automobile chassis part which is excellent in low cycle fatigue characteristics, characterized by being formed by steel which contains, by mass %, C: 0.02 to 0.10%, Si: 0.05 to 1.0%, Mn: 0.3 to 2.5%, P: 0.03% or less, S: 0.01% or less, Ti: 0.005 to 0.1%, Al: 0.005 to 0.1%, N: 0.0005 to 0.006%, and B: 0.0001 to 0.01 and has a balance of Fe and unavoidable impurities, in which 80% or more of the part structure comprises a bainite structure and in which a portion where a ratio R/t of the thickness “t” and external surface curvature radius R is 5 or less has an X-ray half width of an (211) plane of 5 (deg) or less. | 03-07-2013 |
20150083282 | SEAMLESS STEEL PIPE AND METHOD FOR PRODUCING THE SAME - There is provided a seamless steel pipe having high strength and high toughness even if having a thick wall. A seamless steel pipe according to the present embodiment consists of: in mass %, C: 0.03 to 0.08%, Si: not more than 0.25%, Mn: 0.3 to 2.0%, P: not more than 0.05%, S: not more than 0.005%, Al: 0.001 to 0.10%, Cr: 0.02 to 1.0%, Ni: 0.02 to 1.0%, Mo: 0.02 to 0.8%, N: 0.002 to 0.008%, Ca: 0.0005 to 0.005%, and Nb: 0.01 to 0.1%, the balance being Fe and impurities, and has a wall thickness of not less than 50 mm. In a cross section perpendicular to an axial direction of the seamless steel pipe, an average crystal grain size of prior austenite grains in a near surface portion is less than 80 μm, the near surface portion being a 500 μm×500 μm area centered at a position of a depth of 2 mm from a surface, and a difference between the average crystal grain size of the prior austenite grains in the near surface portion and an average crystal grain size of prior austenite grains in a central portion of a wall thickness of the cross section is less than 50 μm, the central portion being a 500 μm×500 μm area centered at a center position of the wall thickness. | 03-26-2015 |
20160010190 | PROCESSES FOR PRODUCING THICKER GAGE PRODUCTS OF NIOBIUM MICROALLOYED STEEL | 01-14-2016 |
20160060738 | STEEL STRUCTURE FOR HYDROGEN GAS, MEHTOD FOR PRODUCING HYDROGEN STORAGE TANK, AND METHOD FOR PRODUCING HYDROGEN LINE PIPE (AS AMENDED) - Provided is a steel structure for hydrogen gas such as a hydrogen storage tank or a hydrogen line pipe which achieves a lower fatigue crack propagation rate in a high-pressure hydrogen atmosphere than steels used in the related art and has high hydrogen embrittlement resistance. The steel structure for hydrogen gas, which has high hydrogen embrittlement resistance in high-pressure hydrogen gas, has a steel microstructure including any one of 10% to 95% of bainite on an area-ratio basis, 10% to 95% of martensite on an area-ratio basis, and 10% to 95% of pearlite on an area-ratio basis, with the balance being substantially ferrite. | 03-03-2016 |
20160160307 | LOW ALLOY OIL WELL STEEL PIPE AND METHOD FOR MANUFACTURING SAME - Low-alloy oil-well steel pipe includes a composition consisting, in mass %, of C: 0.40 to 0.65%, Si: 0.05 to 0.50%, Mn: 0.10 to 1.00%, P: 0.020% or less, S: 0.0020% or less, Cu: 0.15% or less, Cr: 0.40 to 1.50%, Mo: 0.50 to 2.50%, V: 0.05 to 0.25%, Ti: 0 to less than 0.01%, Nb: 0.01 to 0.2%, sol.Al: 0.010 to 0.100%, N: 0.006% or less, B: 0 to 0.0015%, and Ca: 0 to 0.003%, the balance being Fe and impurities. The structure has tempered martensite and 0 to less than 2% volume ratio of retained austenite. A grain size number of prior-austenite grain in the structure is 9.0 or more. An equivalent circular diameter of a sub-structure surrounded by a boundary having a crystal orientation difference of 15° or more from a packet boundary, a block boundary and a lath boundary is 3 μm or less for the tempered martensite. | 06-09-2016 |
20160376677 | METHOD FOR PRODUCING A TEMPERED SEAMLESSLY HOT-FABRICATED STEEL PIPE - A method for producing a tempered, seamlessly hot-rolled steel pipe includes heating a hollow block to forming temperature and rolling the heated block in a rolling mill to form a pipe with a finished diameter after rolling. Subsequently, the pipe is tempered with appropriate tempering parameters after rolling whereby the diameter of the pipe increases during tempering. The finished diameter of the pipe to be tempered after rolling in the rolling mill is adjusted as a function of a value of the growth in diameter of the pipe during tempering. | 12-29-2016 |