Abstract: A cold die steel excellent in the characteristic of suppressing dimensional change, which has a chemical composition in mass %: C: 0.7% or more and less than 1.6%, Si: 0.5 to 3.0%, Mn: 0.1 to 3.0%, P: less than 0.05% including 0%, S: 0.01 to 0.12%, Cr: 7.0 to 13.0%, one or two elements selected from the group consisting of Mo and W: amounts satisfying the formula (Mo+(W/2))=0.5 to 1.7%, V: less than 0.7% including 0, Ni: 0.3 to 1.5%, Cu: 0.1 to 1.0% and Al: 0.1 to 0.7%. Preferably, the die steel satisfies the formula in mass %: Ni/Al=1 to 3.7. It is preferred that the die steel also satisfies the following formula in mass %: (Cr?4.2×C)=5 or less and (Cr?6.3×C)=1.4 or more and that it contains 0.3% or less of Nb.

Abstract: 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 ?m 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.

Abstract: The invention concerns an iron-nickel alloy strip comprising the following expressed in wt. %: 32?Co+Ni?45%, 0?Co?6.5%, 0?Cr=6.5%, Cu?3%, Si?0.5%, Mn?0.75%, the rest being made up of iron and unavoidable impurities resulting from production, whereof the microstructure has a recrystallized volume fraction ranging from 3 to 97%, whereof the thickness is less than 0.5 mm. The invention also concerns the use thereof in the manufacture of support grids for integrated circuits.

Abstract: The present invention provides a tool steel containing, by mass percent, 0.55 to 0.85% of C, 0.20 to 2.50% of Si, 0.30 to 1.20% of Mn, 0.50% or less of Cu, 0.01 to 0.50% of Ni, 6.00 to 9.00% of Cr, 0.1 to 2.00% of Mo+0.5 W, and 0.01 to 0.40% of V, with the balance of Fe and inevitable impurities, in which, when an area rate of a coarse carbide having a circle equivalent diameter of 2 pm or more in a cross section parallel to a forging direction is represented by L(%) and an area rate of the coarse carbide in a cross section perpendicular to the forging direction is represented by T(%), the area rate L is 0.001% or more, the area rate T is 0.001% or more, and the ratio L/T is within a range from 0.90 to 3.00. The tool steel of the invention exhibits an isotropic size change in quenching and tempering.

Abstract: A low carbon alloy steel tube and a method of manufacturing the same, especially for a stored gas inflator pressure vessel, in which the steel tube consists essentially of, by weight: about 0.06% to about 0.18% carbon, about 0.3% to about 1.5% manganese, about 0.05% to about 0.5% silicon, up to about 0.015% sulfur, up to about 0.025% phosphorous, and at least one of the following elements: up to about 0.30% vanadium, upto t about 0.10% aluminum, up to about 0.06% niobium, up to about 1% chromium, up to about 0.70 % nickel, up to about 0.70% molybdenum, up to about 0.35% copper, up to about 0.15% residual elements, and the balance iron and incidental impurities. After a high heating rate of about 100° C. per second; rapidly and fully quenching the steel tubing in a water-based quenching solution at a cooling rate of about 100° C. per second. The steel has a tensile strength of at least about 145 ksi and as high as 220 ksi and exhibits ductile behavior at temperatures as low as ?100° C.

Abstract: The present invention provides a grain-oriented electrical steel sheet produced by a method for promoting secondary recrystallization without an inhibitor, the grain-oriented electrical steel sheet including 2.0% or more and 4.5% or less of Si and 0.01% or more and 0.5% or less of Mn on a mass % basis, wherein the number of oxide particles having a diameter of 1 to 3 ?m among that (oxide particles) of containing Ca and/or Mg is 400 or less per unit area (1 cm2) in a transverse cross-section perpendicular to a rolling direction. Therefore, the grain-oriented electrical steel sheet has excellent stable magnetic properties throughout the length of a coil.

Abstract: A low yield ratio, high toughness steel plate which can be manufactured at high manufacturing efficiency and low cost, without increasing material cost by adding large amount of alloy elements and the like, and without degrading toughness of a welding heat affected zone, a low yield ratio, high strength and high toughness steel pipe using the steel plate, and a method for manufacturing those are provided. Specifically, the steel plate and the steel pipe contain C of 0.03% to 0.1%, Si of 0.01 to 0.5%, Mn of 1.2 to 2.5% and Al of 0.08% or less, wherein a metal structure is a substantially three-phase structure of ferrite, bainite and island martensite, and an area fraction of the island martensite is 3 to 20%, in addition, a complex carbide is precipitated in the ferrite phase.

Abstract: The present invention provides spring use heat treated steel which is cold coiled, can achieve both sufficient atmospheric strength and coilability, has a tensile strength of 2000 MPa or more, and can improve the performance as a spring by heat treatment after spring fabrication, that is, high strength spring-use heat treated steel characterized by containing, by mass %, C: 0.45 to 0.9%, Si: 1.7 to 3.0%, and Mn: 0.1 to 2.0%, restricting N: to 0.007% or less, having a balance of Fe and unavoidable impurities, and satisfying, in terms of the analyzed value of the extracted residue after heat treatment, [amount of Fe in residue on 0.2 ?m filter/[steel electrolysis amount]×100?1.1.

Abstract: The present invention provides a high strength bolt excellent in delayed fracture resistance able to advantageously prevent hydrogen embrittlement as represented by the delayed fracture phenomenon occurring along with an increase in strength and causing a particular problem, and a method of production of the same, containing, by mass %, C: 0.2 to 0.6%, Si: 0.05 to 0.5%, Mn: 0.1 to 2%, Mo: 0.5 to 6%, and Al: 0.005 to 0.5%, having a tensile strength of 1400 MPa or more, and having a compressive residual stress of the surface layer of the thread root of 10 to 90% of the tensile strength. Further, a surface layer part of the thread root from the surface down to at least 50 ?m has pre-austenite grains with an aspect ratio of the axial direction and radial direction of 2 or more and that part has a hardness of Hv 460 or more. Further, the method of production comprises using the steel material having the above ingredients to shape the bolt head and shaft, then heat the bolt to 900 to 1100° C.

Abstract: A high-strength hot-rolled steel sheet containing C: 0.05 to 0.15%, Si: no more than 1.50% (excluding 0%), Mn: 0.5 to 2.5%, P: no more than 0.035% (excluding 0%), S: no more than 0.01% (including 0%), Al: 0.02 to 0.15%, and Ti: to 0.2%, which is characterized in that its metallographic structure is composed of 60 to 95 vol % of bainite and solid solution-hardened or precipitation-hardened ferrite (or ferrite and martensite) and its fracture appearance transition temperature (vTrs) is no higher than 0° C. as obtained by impact tests.

Abstract: A high-strength hot-rolled steel sheet excellent in shape fixability having ferrite or bainite as the phase of the largest volume percentage, satisfying all of the following at least at ½ sheet thickness: a mean value of X-ray random intensity ratio in the orientation component group of {100}<011> to {223}<110> to X-ray random diffraction intensity ratio of at least 2.5; a mean value of X-ray random intensity ratio in the three crystal orientation components of {554}<225>, {111}<112>, and {111}<110> to X-ray random diffraction intensity ratio of 3.5 or less; an X-ray intensity ratio to X-ray random diffraction intensity ratio at {100}<011> of at least the X-ray random intensity to X-ray random diffraction intensity ratio at {211}<011>; and an X-ray random intensity ratio to X-ray random intensity ratio diffraction intensity ratio at {100}<011> of at least 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: Disclosed herein is a spring wire rod excelling in fatigue characteristics. It contains TiN inclusions having a specific size defined by the ratio of each group in all the visual fields as follows: (1) Visual fields in which the maximum thickness is no larger than 5 ?m: less than 5% (2) Visual fields in which the maximum thickness is larger than 5 ?m and no larger than 10 ?m: no more than 30% (3) Visual fields in which the maximum thickness is larger than 10 ?m and no larger than 25 ?m: no less than 70% (4) Visual fields in which the maximum thickness is larger than 25 ?m: less than 5% The visual field is the cross section passing through the center line of the wire rod.

Abstract: Accordingly to an exemplary embodiment of the present invention, a high tensile strength, refractory steel can be provided which comprises, in mass %, approximately C: 0.04 to 0.14%, Si: 0.50% or less, Mn: 0.50 to 2.00%, P: 0.020% or less, S: 0.010% or less, Nb: 0.01 to 0.05%, Mo: 0.30% or more and less than 0.70%, Al: 0.060% or less, N: 0.0010 to 0.0060%, and the balance consisting of iron and unavoidable impurities. For example, a weld crack sensitive composition PCM can be defined by the following equation may be about 0.25% or less: PCM=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B. An area fraction of polygonal ferrite or pseudo polygonal ferrite in a ¼ thick position in the plate thickness direction of the steel plate of the final rolling product is about 10% or less.

Abstract: There is provided a high-strength hot-dip galvanized steel sheet having excellent formability, the steel sheet eliminating special pre-structure control and capable of being produced by using a hot-dip galvanized steel-sheet production line that is not capable of sufficiently ensuring an austempering time after annealing. A high-strength hot-dip galvanized steel sheet includes, on the basis of mass percent, 0.05-0.3% C, 1.4% or less (including 0%) Si, 0.08%-3% Mn, 0.003-0.1% P, 0.07% or less S, 0.1-2.5% Al, 0.1-0.5% Cr, and 0.007% or less N, Si+Al?0.5%, and the balance being Fe and incidental impurities, wherein the steel sheet has a retained austenite content of 3% or more by volume fraction, and wherein the average aspect ratio of retained austenite grains is 2.5 or less.

Abstract: A hot-rolled wire rod excelling in wire drawability is provided, in which breakage can be suppressed even in heavy work from a large diameter. A hot-rolled wire rod contains C: 0.35 to 0.65% (percent by mass, hereinafter expressed as well), Si: 1.4 to 3.0%, Mn: 0.10 to 1.0%, Cr: 0.1 to 2.0%, P: 0.025% or less (exclusive of 0%), S: 0.025% or less (exclusive of 0%), N: 0.006% or less (exclusive of 0%), Al: 0.1% or less (exclusive of 0%), and O: 0.0030% or less (exclusive of 0%), with the remnant consisting of Fe and inevitable impurities; wherein the content of hydrogen in steel is 2.50 ppm (ppm by mass, hereinafter expressed as well) or less, and hardness (HV) is 460×C00.1 or less (C0 indicates the content of C (percent by mass) in a position of depth of D/4 (D: diameter of the wire rod)).

Abstract: A graphite-containing, heat-resistant cast iron for exhaust equipment members used at temperatures exceeding 800° C., comprising 3.5-5.6% of Si and 1.2-15% of W on a weight basis, and having intermediate layers, in which W and Si are concentrated, in the boundaries of graphite particles and a matrix. An exhaust equipment member formed by this heat-resistant cast iron has an AC transformation point is 840° C. or higher when measured from 30° C. at a temperature-elevating speed of 3° C./minute, and a thermal cracking life of 780 cycles or more in a thermal fatigue test, in which heating and cooling are conducted under the conditions of an upper-limit temperature of 840° C., a temperature amplitude of 690° C. and a constraint ratio of 0.25.

Abstract: A spring steel with high fatigue resistance in air and in corrosive conditions and with high resistance to cyclic sag, having the composition in weight percent: C=0.45-0.70% Si=1.65-2.50% Mn=0.20-0.75% Cr=0.60-2% Ni=0.15-1% Mo=traces-1% V=0.003-0.8% Cu=0.10-1% Ti=0.020-0.2% Nb=traces-0.2% AI=0.002-0.050% P=traces-0.015% S=traces-0.015% O=traces-0.0020% N=0.0020-0.0110% the balance being iron, and impurities resulting from the steel making process, where the carbon equivalent Ceq content calculated according to the formula: Ceq %=[C %]+0.12 [Si %]+0.17 [Mn %]?0.1 [Ni %]+0.13 [Cr %]?0.24 [V %] is between 0.80 and 1.00%, and whose hardness, after quenching and tempering, is greater than or equal to 55 HRC.

Abstract: The invention discloses an object comprising at least one part made of steel, the composition of which comprises, the contents being expressed by weight, carbon with a content of between 0.005 and 0.27%, manganese between 0.5 and 1.6%, silicon between 0.1 and 0.4%, chromium in a content of less than 2.5%, Mo in a content of less than 1%, optionally one or more elements chosen from nickel, copper, aluminum, niobium, vanadium, titanium, boron, zirconium and nitrogen, the balance being iron and impurities resulting from the smelting, said steel part including at least one zone welded by a high-energy-density beam, characterized in that said welded zone has a microstructure consisting of 60 to 75% self-tempered martensite and, to complement this, 40 to 25% lower bainite, and preferably 60 to 70% self-tempered martensite and, to complement this, 40 to 30% lower bainite.

Abstract: The present invention provides a high tension steel plate of a tensile strength of 570 MPa or more with a small acoustic anisotropy and with excellent weldability tensile strength and a method of production of steel plate predicated on the high productivity accelerated cooling stop process, which steel sheet is a high tension steel plate with a value of 0.045%?Nb+2Ti?0.105%, A=(Nb+2Ti)×(C+N×12/14) satisfying 0.0025 to 0.0055 and with a steel composition containing bainite in an amount of 30 vol % or more and pearlite+martensite-austenite constituent (MA) in an amount of less than 5 vol %. The steel is heated to 1200° C. or more, rough rolled at 1020° C. or more, then rolled at a cumulative reduction rate from over 920° C. to less than 1020° C. of 15% or less and a cumulative reduction rate from 860 to 920° C. of 20 to 50%, then starting accelerated cooling giving a cooling rate of 2 to 30° C./sec at 800° C. or more, stopping the accelerated cooling at 600 to 700° C., then cooling by 0.4° C./sec or less.

Abstract: The present invention provides a method of production of oil country tubular goods having a small drop in collapse pressure after expansion and having a collapse pressure recovering by low temperature ageing at about 100° C. and oil country tubular goods obtained by this method of production. This method of production comprises hot rolling a steel slab having amounts of addition of C, Mn, P, S, Nb, Ti, Al, and N in specific ranges and having a balance of iron and unavoidable impurities and shaping the steel strip coiled at a temperature of not more than 300° C. as it is into a tube. Alternatively, it comprises heating steel pipe having amounts of addition of C, Mn, P, S, Nb, Ti, Al, and N in specific ranges and having a balance of iron and unavoidable impurities to a temperature of the Ac3 [° C.] to 1150° C., then cooling it in a range of 400 to 800° C. at a rate of 5 to 50° C./second.

Abstract: A steel sheet having (a) a dual phase microstructure with a martensite phase and a ferrite phase and (b) a composition containing by percent weight: 0.01% to 0.2% C; 0.3% to 3% Mn; 0.05% to 2% Si; 0.1% to 2% Cr; 0.01% to 0.10% Al; and 0.0005% to 0.01% Ca, with the balance of the composition being iron and incidental ingredients. Also, the steel sheet is made by a batch annealing method, and has a tensile strength of at least approximately 400 MPa and an n-value of at least approximately 0.175.

Abstract: 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.

Abstract: The present invention provides a method for manufacturing high tensile strength steel plate having 570 MPa (N/mm2) or larger tensile strength and having also extremely superior balance of strength and toughness both before PWHT and after PWHT to that of the conventional steel plates, by specifically specifying the temperature-rising rate at the plate thickness center portion of a quenched and tempered material during tempering, and to be concrete, the method has the steps of: casting a steel consisting essentially of 0.02 to 0.18% C, 0.05 to 0.5% Si, 0.5 to 2.0% Mn, 0.005 to 0.1% Al, 0.0005 to 0.008% N, 0.03% or less P, 0.

Abstract: Coating steel strips comprising, in % by weight, C: ?1.6%, Mn: 6-30%, Al: ?10%, Ni: ?10%, Cr: ?10%, Si: ?8%, Cu: ?3%, Nb: ?0.6%, Ti: ?0.3%, V: ?0.3%, P: ?0.1%, B: ?0.01%, the rest being iron and unavoidable impurities, and a method of forming steel strips are described. Up to now, such steel strips were not adequately coatable, with a metal coating ensuring outstanding corrosion-resistance and good welding properties. This is ensured by applying an aluminium layer to the steel strip before final annealing and applying the metal coating to said aluminium layer after final annealing.

Abstract: The invention provides a hot-working die steel for die-casting obtainable by quenching a steel comprising, in terms of % by mass, C: 0.1 to 0.3%, Si: 0.1 to 1.5%, Mn: 0.3 to 2%, Cr: 6 to 12%, P: 0.05% or less, S: 0.01% or less, Mo: 1 to 3%, V: 0.5 to 1.5%, s-Al: 0.005 to 0.025%, N: 0.005 to 0.025%, and O: 0.005% or less, with the remainder being Fe and inevitable impurities, followed by tempering the steel at a temperature of 500° C. or lower.

Abstract: A hot forged product including hardened areas introduced by partial cooling after hot forging, and unhardened areas, wherein Vickers hardness V1 of the hardened areas on the surface and Vickers hardness V2 of the unhardened areas satisfy the following formula (1): (V1?V2)/V2: 0.1 to 0.8.

Abstract: A high copper low alloy steel sheet less than 5 mm is made by preparing a molten melt producing an as-cast low alloy steel comprising by weight, 0.02 % to 0.3% carbon, 0.10% to 1.5% manganese, 0.01% to 0.5% silicon, greater than 0.01 % and less than or equal 0.15% phosphorus, less than 0.05% aluminum, more than 0.20% copper, less than 0.03 % tin, less than 0.10 % nickel, total oxygen level at least 70 ppm and usually less than 250 ppm, free oxygen content 20 to 70 ppm, the remainder iron and impurities, solidifying the melt into sheet less than 10 mm thickness in a non-oxidizing atmosphere to below 1080° C. Copper content may be between 0.2% and 2.0% by weight. The steel may have a corrosion index (I) of at least 6.0 in accordance with ASTM G101 where: I=26.01 (% Cu)+3.88 (% Ni)+1.20 (% Cr)+1.49 (% Si)+17.28 (% P)?7.29 (% Cu)(% Ni)?9.10 (% Ni)(% P)?33.39 (% Cu)2. The steel may be produced by twin roll casting, and may be less than 2 mm thickness.

Abstract: Provided are a steel sheet for an automotive muffler and a method for producing the steel sheet. The steel sheet includes 0.01% by weight or less of C, 0.1 to 0.3% by weight of Si, 0.3 to 0.5% by weight of Mn, 0.015% by weight or less of P, 0.015% or less by weight of S, 0.02 to 0.05% by weight of Al, 0.004% or less of N, 0.2 to 0.6% by weight of Cu, 0.01 to 0.04% by weight of Co, and a remainder of Fe and unavoidable impurities. The method includes 0.01% by weight or less of C, 0.1 to 0.3% by weight of Si, 0.3 to 0.5% by weight of Mn, 0.015% by weight or less of P, 0.015% or less by weight of S, 0.02 to 0.05% by weight of Al, 0.004% or less of N, 0.2 to 0.6% by weight of Cu, 0.01 to 0.

Abstract: 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. An as-quenched seamless steel pipe having a chemical composition consisting of, by mass %, C: 0.03 to 0.08%, Mn: 0.3 to 2.5%, Al: 0.001 to 0.10%, Cr: 0.02 to 1.0%, Ni: 0.02 to 1.0%, Mo: 0.02 to 0.8%, Ti: 0.004 to 0.010%, N: 0.002 to 0.008%, Ca: 0.0005 to 0.005%, and the balance Fe and impurities, with not more than 0.25% of Si, not more than 0.05% of P, not more than 0.005% of S, less than 0.005% of Nb, and less than 0.0003% of B as the impurities, and having a microstructure consisting of not more than 20 volume % of polygonal ferrite, not more than 10 volume % of a mixed microstructure of martensite and retained austenite, and the balance bainite. B can be 0.0003 to 0.001%. Mg and/or REM can be contained. The manufacturing method is characterized by the cooling rate during quenching.

Abstract: The invention relates to a method for producing a siderurgical product made of carbon steel having a high copper content, according to which:—a liquid steel having the composition: 0.0005% 1%; 0.5 Cu 10%; 0 Mn 2%; 0 Si 5% 0 Ti 0.5%; 0 Nb 0.5%; 0 Ni 5%; 0 Al 2%, the remainder being iron and impurities, is produced;—said liquid steel is poured directly in the form of a thin strip having a thickness of no more than 10 mm;—the strip is subjected to forced cooling and/or is surrounded by a non-oxidizing atmosphere while having a temperature of more than 1000? C;—said thin strip is hot rolled at a reduction rate of at least 10%, the temperature at the end of the rolling process being such that all of the copper is still in a solid solution in the ferrite and/or austenite matrix;—and the strip is coiled. The invention also relates to a siderurgical product obtained according to said method.

Abstract: A high-strength cold-rolled steel sheet excellent in uniform elongation, including in percent by mass: 0.10-0.28% of C; 1.0-2.0% of Si; and 1.0-3.0% of Mn, and the structures of the same having the space factors below to the entire structure: 30-65% of bainitic ferrite; 30-50% of polygonal ferrite; and 5-20% of residual austenite.

Abstract: The invention relates to a steel for the production of submarine hulls, which is characterised in that the chemical composition thereof comprises, by weight percent: 0.03%?C<0.08%; 0.04%?Si?0.48%; 0.1%?Mn?1.4%; 2%?Ni?4%; Cr?0.3%; 0.3%?Mo+W/2+3(V+Nb/2+Ta/4)?0.89%; Mo?0.15%; V+Nb/2+Ta/4?0.004%; Nb?0.004%; Cu?0.45%; Al?0.1%; Ti?0.04%; N?0.03%; the remainder comprising iron and impurities resulting from production, boron being an impurity with a concentration of less than 0.0005% and P+S?0.015%, the chemical composition satisfying condition 410?540×C0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)]0.30?460. The inventive steel has an essentially martensitic or lower bainitic structure comprising at least 90% martensite or lower bainite, at most 5% residual austenite, at most 5% ferrite. The steel has a yield strength of between 480 MPa and 620 Mpa and a Charpy toughness V, KCV at ?60° C. of more than 50 J.

Abstract: Non-heat treated steel for soft-nitriding to form parts having high fatigue strength and excellent bend leveling property even in a case of applying soft-nitriding without thermal refining, comprising, by mass %, C: 0.30 to 0.45%, Si: 0.1 to 0.5%, Mn: 0.6 to 1.0%, Ti: 0.005-0.1% and N: 0.015 to 0.030%, and the balance Fe and impurities, having a mixed microstructure of bainite and ferrite whose bainite fraction is 5 to 90% or having a mixed microstructure of bainite, ferrite and pearlite whose bainite fraction is 5 to 90%, the steel could contain one or more of elements of Nb: 0.003 to 0.1% Mo: 0.01 to 1.0%, Cu: 0.01-1.0%, Ni: 0.01 to 1.0%, B: 0.001 to 0.005%, S: 0.01 to 0.1%, and Ca: 0.0001 to 0.005.

Abstract: The present invention provide a TRIP-type composite structure steel plate of the TPF steel type in which elongation and stretch flange formability at room temperature are improved by controlling the morphology of the second-phase structure. In a composite structure sheet steel comprising 0.02 to 0.12% C, 0.5 to 2.0% Si+Al and 1.0 to 2.0% Mn, with the remainder being Fe and unavoidable impurities, and comprising 80% or more polygonal ferrite (steel structure space factor) and 1 to 7% retained austenite, with the remainder being bainite and/or martensite, wherein the elongation and stretch flange formability of the composite sheet steel are improved by reducing the number of bulky, massive second phases with an aspect ratio of 1:3 or less and a mean grain size of 0.5 ?m or more in the second phase of this composite structure, which comprises retained austenite and martensite.

Abstract: The invention relates to a rolling bearing which provides superior noiselessness and high corrosion resistance and longer life, and is manufactured at a low cost, a material for the rolling bearing, and an instrument including a rotating portion using the rolling bearing. A plurality of rolling elements are provided between an inner ring and an outer ring. At least one of the inner and outer rings and is formed of corrosion resistant bearing steel comprising a specific chemical component. The corrosion resistant bearing steel comprises eutectic carbides having an average value of circle equivalent diameter of 0.2 to 1.6 ?m, an average area of 0.03 to 2 ?m2, and an area ratio of 2 to 7%. The hardness of the corrision resistant bearing steel is HRC 58 to 62 by JIS. The amount of retained austenite in the corrosion resistant bearing steel is 6 volume % or less.

Abstract: The invention provides a high tensile strength steel material having a tensile strength of 600 MPa, which is excellent in delayed fracture resistance property, and a method of manufacturing the steel material. As means for this, a steel material contains, in mass percent, C of 0.02 to 0.25%, Si of 0.01 to 0.8%, Mn of 0.5 to 2.0%, Al of 0.005 to 0.1%, N of 0.0005 to 0.008%, P of 0.03% or less, and S of 0.03% or less. In addition, the steel material contains at least one element selected from Mo, Nb, V, and Ti, and contains at least one of Cu, Ni, Cr, W, B, Ca, REM and Mg, as needed. The remainder includes Fe and inevitable impurities. In addition, in the steel material, precipitates having an average grain size of 20 nm or less, which contains at least one of Mo, Nb, V and Ti, are contained in steel in the number of at least 5 per 250000 nm2, and a microstructure includes residual austenite in a volume fraction of 0.5 to 5%. When Ca to be added is specified to be 0.0010% to 0.

Abstract: Clutch components for automotive use usually include a pair of clutch members with operative faces. In particular, planar one way clutches include a pair of clutch members whose operative faces are enclosed spaced opposition, with each clutch face including a plurality of recessed defining respective load bearing shoulders. A plurality of struts are disposed between the coupling face of the members, and such struts are moveable between the coupling position and non coupling position. A preferable method of manufacturing such clutch components includes powder metal operations comprising die compacting a metal powder into a metal blank, sintering the metal blank to form a sintered metal blank, and cooling the sintered metal blank to form a cooled metal blank. The preferred metallic structure of the cooled metal blank is 50-80% martensite and 20-50% bainite and fine pearlite. The application is especially useful for clutches used as backing plates in clutch brake applications.

Abstract: The invention provides a method of fabricating a steel part, the method comprising the steps of: preparing and casting a steel having the following composition in percentage by weight: 0.06%?C?0.25%; 0.5%?Mn?2%; traces?Si?3%; traces?Ni?4.5%; traces?Al?3%; traces?Cr?1.2%; traces?Mo?0.30%; traces?V?2%; traces?Cu?3.5%; and satisfying at least one of the following conditions: 0.5%?Cu?3.5%; 0.5%?V?2%: 2?Ni?4.5% and 1%?Al?2%; ?the remainder being iron and impurities resulting from preparation; hot deforming the cast steel at least once at a temperature in the range 1100° C. to 1300° C. in order to obtain a blank of the part; controlled cooling of the blank for the part in still air or forced air; and heating the steel to perform precipitation annealing before or after machining the part from said blank. The invention also provides a part obtained by the method.

Abstract: The very thin, high carbon wire is 0.05 to 0.50 mm in diameter and comprises, in mass %, 0.90-1.20% of C, 0.05-1.2% of Si, 0.2-1.0% of Mn, and 0.0050% or less of N, with the balance being iron and impurities. In a differential scanning thermal analysis curve A of the steel wire, the steel wire has an exothermic peak X in the temperature range of 60° to 130° C., and a maximum height h of the exothermic peak X relative to a reference line Y joining the point of 60° C. and the point of 130° C. in the differential scanning thermal analysis curve is set at 5 ?W/mg or more. The very thin, high carbon steel wire is free of delamination in high-speed stranding and superior in both strength and ductility.

Abstract: A steel sheet containing 0.004 to 0.02% C, 1.0% or less Si, 0.7 to 3.0% Mn, 0.02 to 0.15% P, 0.02% or less S, 0.01 to 0.1% Al, 0.004% or less N, 0.2% or less Nb, by mass %, optionally Ti, Bi or at least one element selected from the group consisting of Cr Mo, Ni and Cu, and the balance being Fe; the Nb content satisfying a formula of (12/93)×Nb*/C?1.0, wherein Nb*=Nb?(93/14)×N, and wherein C, N and Nb designate the content in mass % of carbon, nitrogen and niobium, respectively; and a yield strength and an average grain size of the ferritic grains which satisfy a formula of YP??120×d+1280, wherein YP designates yield strength in MPa, and d designates an average size of ferritic grains in ?m.

Abstract: A welding structural steel product exhibiting a superior heat affected zone toughness, comprising, in terms of percent by weight, 0.03 to 0.17% C, 0.01 to 0.5% Si, 0.4 to 2.0% Mn, 0.005 to 0.2% Ti, 0.0005 to 0.1% Al, 0.008 to 0.030% N, 0.0003 to 0.01% 0.00 1 to 0.2% W, at most 0.03% P, at most 0.03% S, at most 0.005% 0, and balance Fe and incidental impurities while satisfying conditions of 1.2?Ti/N?2.5, 10?N/B?40, 2.5?Al/N?7, and 6.5?(Ti+2Al+4B)/N?14, and having a microstructure essentially consisting of a complex structure of ferrite and pearlite having a grain size of 20 ?m or less. The method includes the steps of preparing a slab of the above-described composition, heating the slab to 1,100° C. to 1,250° C. for 60-180 minutes, hot rolling the heated slab in an austenite recrystallization range at a 40% or more rolling reduction followed by controlled cooling.

Abstract: A relatively high strength high toughness medium Carbon Copper-Nickel-Chromium alloy steel and method that eliminates and/or reduces the use of scarce, expensive alloying elements and is lower in cost than existing high strength high toughness alloy steels with comparable strength and toughness properties. In a first embodiment, the alloy steel is comprised of by weight about 0.40–1.00% Copper, about 2.50–8.00% Nickel, and about 0.80–3.50% Chromium. In a second embodiment the alloy steel is comprised of by weight about 0.55–0.70% Copper, about 1.0–6.0% Nickel, and about 1.0–2.2% Chromium.

Abstract: A steel plate for paint use which contains C (0.12% or less), Si (1.0% or less), Mn (2.5% or less), P (0.05% or less), S (0.02% or less), and Cr (0.05% or less), Cu (0.05–3.0%), Ni (0.05–6.0%), Ti (0.025–0.15%), and Cu+Ni (0.50% or more), with PCM being 0.23% or less, in terms of mass %. Said steel plate may contain at least one additional component selected from B (0.0005–0.0030%), Al (0.05–0.50%), Ca (0.0001–0.05%), Ce (0.0001–0.05%), La (0.0001–0.05%), Nb (0.002–0.05%), V (0.01–0.10%), Zr (0.002–0.05%), and Mo (0.05–0.5%), in terms of mass %. This steel plate provides good weldability as well as good painting durability in a salt-polluted environment.

Abstract: A ferritic steel sheet wherein a mean value of X-ray random intensity ratios of a group of {100}<011> to {223}<110> orientations is 3.0 or more and a mean value of X-ray random intensity ratios of three crystal orientations of {554}<225>, {111}<112>, and {111}<110> is 3.5 or less and further at least one of the r values in a rolling direction and a direction at a right angle of that is 0.7 or less.

Abstract: The present invention presents a high tensile strength cold rolled steel sheet having excellent formability, impact resistance and strain age hardening characteristics, and the production thereof. As a specific means, a slab having a composition which contains, by mass %, 0.15% or less of C, 0.02% or less of Al, and 0.0050 to 0.0250% of N at N/Al of 0.3 or higher, and has N in a solid solution state at 0.0010% or more, is first hot rolled at the finish rolling delivery-side temperature of 800° C. or above, and is subsequently coiled at the coiling temperature of 750° C. or below to prepare a hot rolled plate. Then, after cold rolling, the hot rolled plate is continuously cooled at a temperature from the recrystallization temperature to 900° C. at a holding time of 10 to 120 seconds, and is cooled by primary cooling in which the hot rolled plate is cooled to 500° C. or below at a cooling rate of 10 to 300° C.

Abstract: A steel sheet composition contains appropriate amounts of C, Si, Mn, P, S, Al and N and 0.5 to 3.0% Cu. A composite structure of the steel sheet has a ferrite phase or a ferrite phase and a tempered martensite phase as a primary phase, and a secondary phase containing retained austenite in a volume ratio of not less than 1%. In place of the Cu, at least one of Mo, Cr, and W may be contained in a total amount of not more than 2.0%. This composition is useful in production of a high-ductility hot-rolled steel sheet, a high-ductility cold-rolled steel sheet and a high-ductility hot-dip galvanized steel sheet having excellent press formability and excellent stain age hardenability as represented by a &Dgr;TS of not less than 80 MPa, in which the tensile strength increases remarkably through a heat treatment at a relatively low temperature after press forming.

Abstract: A cold rolled steel sheet which has an excellent corrosion resistance to sulfuric acid, the steel includes in weight %: 0.15% or less of C, 1.0% or less of Si, 0.2˜1.5% of Mn, 0.03% or less of S, 0.03% or less of P, 0.01˜0.1% of Al, 0.2˜1.0% of Cu, 0.02˜0.2% of Co, and a balance of Fe and other unavoidable impurities.

Abstract: A welding method includes performing welding to form a weld metal consisting essentially of, in mass %, 1 C: 0.01-0.15%, Si: 0.02-0.6%, Mn: 0.6-3.0%, Al: 0.004-0.08%, Ti: 0.003-0.03%, B: at most 0.005%, Cu: 0-1.2%, Ni: 0-3%, Cr: 0-1.2%, Mo: 0-2%, V: 0-0.05%, Nb: 0-0.

Abstract: The present invention provides a steel sheet having a chemical composition comprising 0.15% or less C, 2.0% or less Si, 3.0% or less Mn, P, S, Al and N in adjusted amounts, from 0.5 to 3.0% Cu, or one or more of Cr, Mo and W in a total amount of 2.0% or less, and having a composite structure comprising ferrite and martensite having an area ratio of 2% or more. The steel sheet is in the form of a high-strength hot-rolled steel sheet, a high-strength cold-rolled steel sheet, or a hot-dip galvanized steel sheet. There is thus available a steel sheet excellent in press-formability and in strain age hardening property as represented by a &Dgr;TS of 80 MPa or more.