Abstract: Disclosed is a cold-rolled steel sheet having a specific steel composition and having a composite steel structure including a ferrite structure and a martensite-containing second phase. In a surface region of the steel sheet from the surface to a depth one-tenth the gage, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cm2 of a rolling plane, in which the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 80 ?m or more. Also disclosed is a cold-rolled steel sheet having a specific steel composition and having a steel structure of a martensite single-phase structure. In the surface region, the number density of groups of inclusions, in which the distance between the outermost surfaces is 100 ?m or more, is 120 or less per 100 cm2 of a rolling plane.

Abstract: A high-strength cold-rolled steel sheet according to the present invention: satisfies the requirement of a prescribed chemical composition; has a structure comprising a mother phase structure of ferrite and a second phase structure of retained austenite and martensite (the martensite may not be included); and satisfies the following expressions (1) and (2) when the volume fraction of the ferrite in the whole structure is represented by Vf (%), the volume fraction of the retained austenite in the whole structure is represented by V? (%), the carbon content in the retained austenite is represented by C? (mass %), the shortest distance between the second phase structures is represented by dis (?m), and the average grain size of the second phase structures is represented by dia (?m), (Vf×V?×C?×dis)/dia?300??(1), dis?1.0 ?m??(2).

Abstract: A bainitic steel alloy and a method for making such an alloy are disclosed, in which the bainite plates are particularly small, less than 50 nanometres in width. In preferred embodiments of the invention, each bainite plate is surrounded by a film of retained austenite; the level of retained austenite in the alloy is greater than 10%; and the alloy is substantially free of blocky unstable austenite and cementite.

Abstract: The present invention provides a high-strength composite steel sheet which has a tensile strength of 980 MPa class as well as excellent and excellent anti-delayed fraction property, and also has excellent spot-weldability. The high-strength composite steel sheet comprises a steel satisfying: C: 0.10 to 0.25% (% by mass in case of a chemical component, the same shall apply hereinafter), Si: 1.0 to 3.0%, Mn: 1.5 to 3.0%, P: 0.15% or less, S: 0.02% or less, Al: 0.4% or less, and comprising the remnant made from iron and unavoidable impurities; the contents of Si, Al, Mn and Cr satisfy the relationship of “(Si+Al)/Mn or (Si+Al)/(Mn+Cr)=0.74 to 1.26”; and microstructure is specified.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel having a free oxygen content between 20 and 75 ppm and having a composition such that the cast strip comprises by weight, less than 0.25% carbon, between 0.9 and 2.0% manganese, between 0.05 and 0.50% silicon, greater than 0.01% and less than or equal to 0.15% phosphorus, and less than 0.01% aluminum, counter rotating the casting rolls forming the steel strip, hot rolling the strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the strip at a temperature between 300 and 700° C. to provide a majority of the microstructure comprising bainite and acicular ferrite. Alternatively, the steel may have between 0.20 and 0.60% copper and manganese as low as 0.08%.

Abstract: The present invention provides a high-strength cold-rolled steel sheet and a high-strength surface treated steel sheet 780 MPa or more in tensile strength, said steel sheets having excellent local formability and suppressed weld hardness increase and being characterized by: said steel sheets containing, in weight, C: 0.05 to 0.09%, Si: 0.4 to 1.3%, Mn: 2.5 to 3.2%, P: 0.001 to 0.05%, N: 0.0005 to 0.006%, Al: 0.005 to 0.1%, Ti: 0.001 to 0.045%, and S in the range stipulated by the following expression (A), with the balance consisting of Fe and unavoidable impurities; the microstructures of said steel sheets being composed of bainite of 7% or more in terms of area percentage and the balance consisting of one or more of ferrite, martensite, tempered martensite and retained austenite; and said components in said steel sheets satisfying the following expressions (C) and (D) when Mneq. is defined by the following expression (B); S?0.08×(Ti(%)?3.43×N(%)+0.004 . . . (A), where, when a value of the member Ti(%)?3.

Abstract: A steel sheet excellent in mechanical strength, workability and thermal stability and suited for use as a raw material in such fields of manufacturing automobiles, household electric appliances and machine structures and of constructing buildings, and a manufacturing method thereof are provided. The steel sheet is a hot-rolled steel sheet of carbon steel or low-alloy steel, the main phase of which is ferrite, and is characterized in that the average ferrite crystal grain diameter D (?m) at the depth of ¼ of the sheet thickness from the steel sheet surface satisfies the relations respectively defined by the formulas (1) and (2) given below and the increase rate X (?m/min) in average ferrite crystal grain diameter at 700° C. at the depth of ¼ of the sheet thickness from the steel sheet surface and said average crystal grain diameter D (?m) satisfy the relation defined by the formula (3) given below: 1.2?D?7??formula (1) D?2.7+5000/(5+350.C+40.Mn)2??formula (2) D·X?0.

Abstract: A high-strength steel sheet has high stretch flangeability after working and corrosion resistance after painting. The steel sheet contains, on the basis of mass percent, C: 0.02% to 0.20%, Si: 0.3% or less, Mn: 0.5% to 2.5%, P: 0.06% or less, S: 0.01% or less, Al: 0.1% or less, Ti: 0.05% to 0.25%, and V: 0.05% to 0.25%, the remainder being Fe and incidental impurities. The steel sheet has a substantially ferritic single phase, the ferritic single phase containing precipitates having a size of less than 20 nm, the precipitates containing 200 to 1750 mass ppm Ti and 150 to 1750 mass ppm V, V dissolved in solid solution being 200 or more but less than 1750 mass ppm.

Abstract: A steel product or thin steel cast strip including, by weight, less than 0.25% carbon, between 0.20 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, and at least one of niobium between 0.01% and 0.20% and vanadium between 0.01% and 0.20%, and a microstructure of a majority bainite and acicular ferrite, and more than 70% niobium and/or vanadium in solid solution. The steel product may have an increase in elongation and an increase in yield strength after age hardening. The age hardened steel product may have niobium carbonitride particles with an average particle size of 10 nanometers and less, and may have substantially no niobium carbonitride particles greater than 50 nanometers. The steel product may have a yield strength of at least 380 MPa, a tensile strength of at least 410 MPa, or both. The product may have a total elongation of at least 6% or 10%.

Abstract: The invention relates to a steel and a processing method for high-strength fracture-splittable machine components that are composed of at least two fracture-splittable parts. The steel and method are characterized in that the chemical composition of the steel (expressed in percent by weight) is as follows: 0.40%?C?0.60%; 0.20%?Si?1.00%; 0.50%?Mn?1.50%; 0%?Cr?1.00%; 0%?Ni?0.50%; 0%?Mo?0.20%; 0%?Nb?0.050%; 0%?V?0.30%; 0%?Al?0.05%; 0.005%?N?0.020%, the rest being composed of iron and smelting-related impurities and residual matter.

Abstract: The present invention provides a high strength steel sheet with 780 MPa class tensile strength excellent in bending workability and fatigue strength. The high strength steel sheet is (1) a steel sheet whose steel composition contains: C: 0.05-0.20%; Si: 0.6-2.0%; Mn: 1.6-3.0%; P: 0.05% or below; S: 0.01% or below; Al: 0.1% or below; and N: 0.01% or below, the balance comprising iron and inevitable impurities, in which (2) a microstructure comprises a polygonal ferrite structure and a structure formed by low-temperature transformation, in which, when a sheet plane located at a depth of 0.1 mm from a surface of the steel sheet is in the observation under a scanning electron microscope with respect to twenty sights in total in different positions in the sheet-width direction, the maximum value of the areal proportion of the polygonal ferrite (Fmax) and the minimum value of the areal proportion of the ferrite (Fmin) in a 50 ?m×50 ?m area in each sight satisfy Fmax?80%, Fmin?10%, and Fmax?Fmin?40%.

Abstract: The present invention provides a high-strength steel sheet which has a 980 MPa class tensile strength as well as has excellent elongation, stretch flangeability and weldability, and also has excellent anti-delayed fraction property. The high-strength steel sheet comprises steel satisfying: C: 0.12 to 0.25%, Si: 1.0 to 3.0%, Mn: 1.5 to 3.0%, P: 0.15% or less, S: 0.02% or less, Al: 0.4% or less, and comprising the remnant made from iron and unavoidable impurities, wherein a ratio of the contents of Si and C (Si/C) is within the range from 7 to 14 in terms of a mass ratio, and a microstructure in a longitudinal section comprises, by an occupancy ratio based on the entire structure, 1) bainitic ferrite: 50% or more, 2) lath-type residual austenite: 3% or more, and 3) block-type residual austenite: 1% or more to ½×occupancy ratio of lath-type residual austenite, and 4) average size of block-type second phase is 10 ?m or less.

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: High-strength steel sheet excellent in hole-expandability and ductility, characterized by; comprising, in mass %, C: not less than 0.01% and not more than 0.20%, Si: not more than 1.5%, Al: not more than 1.5%, Mn: not less than 0.5% and not more than 3.5%, P: not more than 0.2%, S: not less than 0.0005% and not more than 0.009%, N: not more than 0.009%, Mg: not less than 0.0006% and not more than 0.01%, O: not more than 0.005% and Ti: not less than 0.01% and not more than 0.20% and/or Nb: not less than 0.01% and not more than 0.10%, with the balance consisting iron and unavoidable impurities, having Mn %, Mg %, S % and O % satisfying equations (1) to (3), and having the structure primarily comprising one or more of ferrite, bainite and martensite. [Mg %]?([O %]/16×0.8)×24??(1) [S %]?([Mg %]/24?[O %]/16×0.8+0.00012)×32??(2) [S %]?0.

Abstract: To provide a high-strength cold rolled steel sheet that has well-balanced tensile strength and elongation as well as well-balanced tensile strength and stretch-flangeability, and a plated steel sheet manufactured by plating the steel sheet. The high-strength cold rolled steel sheet contains: 0.10 to 0.28% of C, 1.0 to 2.0% of Si, 1.0 to 3.0% of Mn, and 0.03 to 0.10% of Nb in terms of % by mass, wherein the content of Al is controlled to 0.5 or less, the content of P is controlled to 0.15% or less, and the content of S is controlled to 0.02% or less, and wherein residual austenite accounts for 5 to 20%, bainitic ferrite accounts for 50% or more, and polygonal ferrite accounts for 30% or less (containing 0%), of the entire structure, and wherein a mean number of residual austenite blocks is 20 or more as determined when the random area (15 ?m×15 ?m) is observed by EBSP (electron back scatter diffraction pattern).

Abstract: There are provided a high-strength hot-rolled steel sheet having excellent weather resistance used for containers and a method of manufacturing the same. A high-strength hot-rolled steel sheet having excellent weather resistance includes, by weight: C: 0.05 to 0.07%, Mn: 2.5% or less, Nb: 0.04 to 0.06%, Ti: 0.08 to 0.10%, Cu: 0.30 to 0.60%, Cr: 0.5 to 1.0%, and Ni: 0.15 to 0.30%, and the balance of Fe and other inevitable impurities. A method of manufacturing the hot-rolled steel sheet is also provided. A hot-rolled steel sheet provided has weather resistance by addition of Cu, Cr, and Ni and material characteristics of a tensile strength within the range of 800 to 900 MPa and a yield strength within the range of 700 to 800 MPa.

Abstract: A high strength cold-rolled steel sheet and a high strength plated steel sheet which have an excellent surface appearance required for outer panels of automobiles and which have an extremely high r value in a direction at 45° with respect to the rolling direction and which have excellent press formability and a tensile strength of at least 340 MPa and a process for their manufacture are provided. The steel sheets have a chemical composition consisting essentially of, in mass %, C: 0.0005-0.025%, Si: at most 0.2%, Mn: 0.3-2.5%, P: at most 0.15%, S: at most 0.02%, N: at most 0.006%, sol. Al: less than 0.005%, Ti: 0.005-0.05%, and Nb: 0.020-0.200% with the mass ratio (Nb/Ti) of the contents of Nb and Ti being at least 2, and a remainder of Fe and impurities, and they have an r value in a direction at 45° with respect to the rolling direction (r45) of at least 1.80 and/or a mean r value (0 of at least 1.60, and a tensile strength of at least 340 MPa.

Abstract: A steel material superior in high temperature characteristics and toughness is provided, that is, a steel material containing, by mass %, C: 0.005% to 0.03%, Si: 0.05% to 0.40%, Mn: 0.40% to 1.70%, Nb: 0.02% to 0.25%, Ti: 0.005% to 0.025%, N: 0.0008% to 0.0045%, B: 0.0003% to 0.0030%, restricting P: 0.030% or less, S: 0.020% or less, Al: 0.03% or less, and having a balance of Fe and unavoidable impurities, where the contents of C and Nb satisfy C?Nb/7.74?0.02 and Ti-based oxides of a grain size of 0.05 to 10 ?m are present in a density of 30 to 300/mm2.

Abstract: The present invention is the thin steel sheet containing C, Si, Mn, P, S, Al, Mo, Ti, B, and N wherein a value Z calculated by the equation described below is 2.0-6.0, an area ratio against all the structure is 1% or above for retained austenite and 80% or above for total of bainitic ferrite and martensite, a mean axis ratio of the retained austenite crystal grain is 5 or above, and tensile strength is 980 MPa or above. Value Z=9×[C]+[Mn]+3×[Mo]+490×[B]+7×[Mo]/{100×([B]+0.001)} Thus a high strength thin steel sheet with 980 MPa or above tensile strength and enhanced hydrogen embrittlement resistance properties can be provided. Also, in accordance with the present invention, the hot-rolled steel sheet for cold-rolling capable of manufacturing the high strength thin steel sheet with good productivity and having improved cold-rollability can be provided.

Abstract: The present invention: provides a good-workability and high-strength cold-rolled steel sheet excellent in post-painting corrosion resistance to the extent of securing excellent resistance to salt warm water immersion which is a good-workability and high-strength cold-rolled steel sheet excellent in post-painting corrosion resistance characterized in that: said steel sheet contains, in mass, 0.16 to 0.19% C, 1.10 to 1.30% Si, 1.50 to 1.60% Mn, not more than 0.1% P and 0.015 to 0.050% Al, with the balance consisting of Fe and unavoidable impurities; the average of the amount of Si incrassating on the surface of said steel sheet is not more than 20 times the Si concentration in said steel sheet; and the area percentage of the portions where the ratio of the Si concentration on the surface of said steel sheet to the Si concentration in said steel sheet is not less than 10 is not more than 95%.

Abstract: Steel sheet having a composition of ingredients containing substantially, by mass %, C: 0.005 to 0.200%, Si: 2.50% or less, Mn: 0.10 to 3.00%, N: 0.0100% or less, Nb: 0.005 to 0.100%, and Ti: 0.002 to 0.150% and satisfying the relationship of Ti-48/14×N?0.0005, having a sum of the X-ray random intensity ratios of the {100}<001> orientation and the {110}<001> orientation of a ? sheet thickness part of 5 or less, having a sum of the maximum value of the X-ray random intensity ratios of the {110}<111> to {110}<112> orientation group and the X-ray random intensity ratios of the {211}<111> orientation of 5 or more, and having a high rolling direction Young's modulus measured by the static tension method and a method of production of the same are provided.

Abstract: This invention provides a forging steel excellent in forgeability, which forging steel comprises, in mass %, C: 0.001 to less than 0.07%, Si: 3.0% or less, Mn: 0.01 to 4.0%, Cr: 5.0% or less, P: 0.2% or less, S: 0.35% or less, Al: 0.0001 to 2.0%, N: 0.03% or less, one or both of Mo: 1.5% or less (including 0%) and Ni: 4.5% or less (including 0%), and a balance of iron and unavoidable impurities; wherein Di given by the following Equation (1) is 60 or greater: Di=5.

Abstract: A steel material superior in high temperature characteristics and toughness is provided, the fire resistant steel material containing by mass %, C: 0.001% to 0.030%, Si: 0.05% to 0.50%, Mn: 0.40% to 2.00%, Nb: 0.03% to 0.50%, Ti: 0.005% to less than 0.040%, and N: 0.0008% to less than 0.0050%, restricting P: 0.030% or less and S: 0.020% or less, and having a balance of Fe and unavoidable impurities, where the contents of C and Nb satisfy C—Nb/7.74?0.004, and Ti-based oxides of a grain size of 0.05 to 10 ?m are present in a density of 30 to 300/mm2.

Abstract: Provided is a hot-working steel excellent in machinability and impact value comprising, in mass %, C: 0.06 to 0.85%, Si: 0.01 to 1.5%, Mn: 0.05 to 2.0%, P: 0.005 to 0.2%, S: 0.001 to 0.35%, and Al: 0.06 to 1.0% and N: 0.016% or less, in contents satisfying Al×N×105?96, and a balance of Fe and unavoidable impurities, total volume of AlN precipitates of a circle-equivalent diameter exceeding 200 nm accounting for 20% or less of total volume of all AlN precipitates.

Abstract: Provided is a low alloy steel for high-pressure hydrogen gas environments, which contains, by mass percent, C: 0.15 to 0.60%, Si: 0.05 to 0.5%, Mn: 0.05 to 3.0%, P: not more than 0.025%, S: not more than 0.010%, Al: 0.005 to 0.10%, Mo: 0.5 to 3.0%, V: 0.05 to 0.30%, O (oxygen): not more than 0.01%, N: not more than 0.03%, and the balance Fe and impurities, and has tensile strength of not less than 900 MPa. This low alloy steel desirably contains B of 0.0003 to 0.003%, but in this case, N is limited to not more than 0.010%. It is desirable to contain at least one among Cr, Nb, Ti, Zr, and Ca. The contents of Mo and V desirably satisfy the following formula (1): [Mo(%)]·[V(%)]0.2?0.32??(1).

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 high strength steel sheet with both excellent elongation and stretch-flanging performance is provided. The high strength steel sheet of the present invention comprises, in percent by mass, C: 0.05 to 0.3%, Si: 0.01 to 3.0%, Mn: 0.5 to 3.0%, Al: 0.01 to 0.1%, and Fe and inevitable impurities as the remainder, and has a structure mainly composed of tempered martensite and annealed bainite. The space factor of the tempered martensite is 50 to 95%, the space factor of the annealed bainite is 5 to 30%, and the mean grain size of the tempered martensite is 10 ?m or smaller in terms of the equivalent of a circle diameter. The steel sheet has a tensile strength of 590 MPa or higher.

Abstract: Disclosed is a steel sheet, containing: Si: 0.20-2% (the term “%” herein means “mass %”, the same is true hereinbelow), Mn: 1-2.5%, a total mass of Si and Mn being 1.5% or more, and O: 0.002% or less (exclusive of 0%), C: 0.02-0.25%, P: 0.1% or less (exclusive of 0%), S: 0.05% or less (exclusive of 0%), Al—0.02-0.2%, and N: 0.0015-0.015%. The steel sheet of the invention can be advantageously used for forming wide beads even in high-speed arc welding of 100 cm/min or higher.

Abstract: A steel sheet contains, in terms of percent by mass, C: 0.01 to 0.2%, Si: 2.0% or less, and Mn: 3.0% or less and has a martensite phase as dominant phase and ferrite with a grain size of 20 ?m or less as a second phase. The ferrite is contained in area ratio of 1% to 30% and the amount of solute carbon being 0.01 percent by mass of more. The steel sheet can provide a hot-rolled steel sheet suitable for automobile steel sheet, i.e., has excellent press workability and excellent strain aging property whereby the tensile strength significantly increases by heat treatment at about the same temperature as typical baking process after the press-working. Moreover, hardening of the ferrite phase improves the fatigue strength after the strain aging.

Abstract: The invention relates to an ultrahigh-strength thin steel sheet excellent in the hydrogen embrittlement resistance, the steel sheet including, by weight %, 0.10 to 0.60% of C, 1.0 to 3.0% of Si, 1.0 to 3.5% of Mn, 0.15% or less of P, 0.02% or less of S, 1.5% or less of Al, 0.003 to 2.0% of Cr, and a balance including iron and inevitable impurities; in which grains of residual austenite have an average axis ratio (major axis/minor axis) of 5 or more, the grains of the residual austenite have an average minor axis length of 1 ?m or less, and the grains of the residual austenite have a nearest-neighbor distance between the grains of 1 ?m or less.

Abstract: A steel sheet for forming having low-temperature heat treatment property, in which heat treatment is performed within a range of lower temperature than a conventional steel sheet in the event of hot press forming or post-heat treatment after cold forming, a method of manufacturing the same, and a method of manufacturing parts using the same. The steel sheet has a composition of, by weight, carbon (C): 0.15 to 0.35%, silicon (Si): 0.5% or less, manganese (Mn): 1.5 to 2.2%, phosphorus (P): 0.025% or less, sulfur (S): 0.01% or less, aluminum (Al): 0.01 to 0.05%, nitrogen (N): 50 to 200 ppm, titanium (Ti): 0.005 to 0.05%, tungsten (W): 0.005 to 0.1%, and boron (B): 1 to 50 ppm, wherein Ti/N: less than 3.4, where Ti/N is the atomic ratio of the corresponding elements, Ceq expressed by the following formula ranges from 0.48 to 0.58, and temperature Ar3 ranges from 670° C. to 725° C. Wherein Ceq=C+Si/24+Mn/6+Ni/40+Cr/5+V/14 where C, Si, Mn, Ni, Cr and V indicate the contents (wt %) of the respective elements.

Abstract: To provide a high strength and low yield ratio cold rolled steel sheet having high elongation property and high flange drawing property, or a plated steel sheet made by plating the same. The high strength and low yield ratio cold rolled steel sheet or the plated steel sheet made by plating the same has such a constitution as 0.10 to 0.25% of C, 1.0 to 2.0% of Si and 1.5 to 3.0% of Mn, are contained in terms of weight percentage, while other elements are controlled such as Al within 0.2%, P within 0.15% and S within 0.02%, with residual austenite occupying at least 5%, bainitic ferrite occupying at least 60% (preferably 80% or more), and polygonal ferrite within 20% (containing 0%), so that a tensile strength is 980 MPa or higher, while an elongation (El in %), a flange drawing property (?in %), a tensile strength (TS in MPa) and a yield strength (YP in MPa) satisfy the following inequality (1): [(El ×?×TS)/YP]?645.

Abstract: For the production of hot strip referred to as TRIP steel (transformation induced plasticity), with a multiphase structure and with outstandingly good deformation properties along with high strengths, from the hot-rolled state, the invention proposes a method which is carried out with a predetermined chemical composition of the steel grade used within the limits 0.12-0.25% C; 0.05-1.8% Si; 1.0-2.0% Mn; the remainder Fe and customary accompanying elements and with a combined rolling and cooling strategy in such a way that a structure comprising 40-70% ferrite, 15-45% bainite and 5-20% residual austenite is obtained, wherein the finish rolling of the hot strip (7) is performed to set a very fine austenite grain (d<8 ?m) in the final forming operation (6?) at temperatures between 770 and 830° C.

Abstract: A main object thereof is to provide a non-oriented electrical steel sheet being excellent in surface characteristics and having both excellent mechanical characteristics and magnetic characteristics necessary for a rotor of rotating machines such as motors and generators which rotate at a high speed, and a method for producing the same. To achieve the object, the present invention provides a non-oriented electrical steel sheet comprising in % by mass: 0.06% or less of C; 3.5% or less of Si; from 0.05% or more to 3.0% or less of Mn; 2.5% or less of Al; 0.30% or less of P; 0.04% or less of S; 0.02% or less of N; at least one element selected from the group consisting of Nb, Ti, Zr and Vin the predetermined range; and a balance consisting of Fe and impurities; and having a recrystallized fraction being less than 90%.

Abstract: A high-ductility, high-strength and high Mn steel strip used for steel strips of automobiles requiring superior formability and high strength, a plated steel strip produced by using the same, and a manufacturing method thereof are disclosed. The high Mn steel strip comprises, by weight %, 0.2˜1.5% of C, 10˜25% of Mn, 0.01˜3.0% of Al, 0.005˜2.0% of Si, 0.03% or less of P, 0.03% or less of S, 0.040% or less of N, and the balance of Fe and other unavoidable impurities. The high-ductility, high-strength and high Mn steel strip, and the plated steel strip produced by using the same have superior surface properties and plating characteristics.

Abstract: An implant having a base body comprising entirely or in part a biocorrodible iron alloy wherein the base body of the implant comprises at least one of the following: (i) a biocorrodible iron alloy of formula (1): Fe—P where the amount of P in the alloy is from 0.

Abstract: The present invention provides steel superior in machinability comprised of, by wt %, C: 0.005 to 0.2%, Si: 0.001 to 0.5%, Mn: 0.2 to 3.0%, P: 0.001 to 0.2%, S: 0.03 to 1.0%, T.N: 0.002 to 0.02%, T.O: 0.0005 to 0.035%, and the balance of Fe and unavoidable impurities, said steel satisfying one or both of Mn/S in the steel being 1.2 to 2.8 or an area ratio of pearlite over a grain size of 1 ?m in a microstructure of the steel being not more than 5%.

Abstract: Provided are a steel-based damping alloy steel sheet having a thickness of 2.0 mm or less which has an excellent damping property of a loss factor of 0.030 or more, and excellent workability, without requiring plenty of elements such as Al, Si, and Cr; and a method for producing the same. Further provided is a damping alloy steel sheet having a thickness of 2.0 mm or less which has an element composition of C: 0.005% or less, Si: less than 1.0%, Mn: 0.05 to 1.5%, P: 0.2% or less, S: 0.01% or less, Sol. Al: less than 1.0%, and N: 0.005% or less, in terms of % by mass, and the remainder containing Fe and inevitable impurities, an average grain diameter of 50 to 300 ?m, a maximum permeability of 4,000 or more, and a residual induction of 1.10 T or less.

Abstract: A steel plate for submerged arc welding having good low temperature toughness at a fusion line vicinity part and a boundary with the base material in HAZ as well as at the base material and the weld metal is provided. The steel plate for submerged arc welding according to the invention contains, by mass, 0.03% to 0.09% C, 1.5% to 2.5% Mn, 0.005% to 0.025% Nb, 0.005% to 0.02% Ti, 0.01% to 0.06% Al, at most 0.0005% B, 0.001% to 0.008% N, at most 0.015% P, at most 0.015% S, and at most 0.006% O, and the balance consists of Fe and impurities. Therefore, the steel plate according to the present invention has good low temperature toughness not only at the fusion line vicinity part and the boundary with a base material in the HAZ but also in the base material and weld metal.

Abstract: A high tensile strength steel sheet excellent in processibility which can satisfy a strength, a total elongation, and stretch-flanging property (hole enlarging rate) at a further high level. and comprises a matrix microstructure of tempered martensite or tempered bainite and, if necessary, ferrite, and a second phase of retained austenite, wherein (1) the steel comprising C: 0.10 to 0.6 mass %, Si: 1.0 mass % or smaller, Mn: 1.0 to 3 ,mass %, Al: 0.3 to 2.0 mass %, P: 0.02 mass % or smaller, S: 0.03 mass % or smaller, (2) a volume rate of retained austenite obtained by a saturated magnetization measuring method is 5 to 40% by area (whole field is 100%), and (3) a relationship of a carbon amount (C: weight %) in the steel, a volume rate (f?R) of retained austenite and a carbon concentration (C?R) of the retained austenite satisfies the equation: (f?R×C?R)/C?50 .

Abstract: The present invention provides spring steel used for spring steel wire achieving both high strength and cold coilability and spring steel wire, that is, spring steel containing, by mass %, C: 0.45 to 0.70%, Si: 1.0 to 3.0%, Mn: 0.05 to 2.0%, P: 0.015% or less, S: 0.015% or less, N: 0.0015 to 0.0200%, and t-O: 0.0002 to 0.01 and further limiting Al?0.01% and Ti?0.003%. Further, it is characterized by satisfying the following regarding the cementite-based spherical carbides present at an observed plane, an occupied area ratio of grains with a circle equivalent diameter of 0.2 ?m or more of 7% or less, a density of presence of grains with a circle equivalent diameter of 0.2 to 3 ?m of 1/?m2 or less, and a density of presence of grains with a circle equivalent diameter 3 ?m or more of 0.

Abstract: Steel sheet, the composition of the steel of which comprises, the contents being expressed by weight: 0.08%?C?0.23%, 1%?Mn?2%, 1?Si?2%, Al?0.030%, 0.1%?V?0.25%, Ti?0.010%, S?0.015%, P?0.1%, 0.004%?N?0.012%, and, optionally, one or more elements chosen from: Nb?0.1%, Mo?0.5%, Cr?0.3%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting.

Abstract: An alloyed hot-dip galvanized steel sheet has a composition containing about 0.05 to about 0.25 wt % of C, about 0.5 wt % or less of Si, about 1 to about 3 wt % of Mn, about 0.1 wt % or less of P, about 0.01 wt % or less of S, about 0.1 to about 2 wt % of Al, and less than about 0.005 wt % of N, and satisfying the relations, Si+Al?0.6 wt %, (0.0006×Al) wt %?N?(0.0058?0.0026×Al) wt %, and Al?(1.25×C0.5?0.57×Si+0.625×Mn) wt %, the balance including Fe and inevitable impurities. The alloyed hot-dip galvanized steel sheet can be obtained without passing through a complicated process, has excellent surface appearance and anti-secondary work embrittlement and high strength, and is thus suitable for application to an automobile steel sheet.

Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.

Abstract: Disclosed herein is a steel for high-speed cold working which exhibits good cold workability during working and also exhibits high hardness after working. The steel for high-speed cold working contains C: 0.03 to 0.6% (by mass), Si: 0.005 to 0.6%, Mn: 0.05 to 2%, P: no more than 0.05% (excluding 0%), S: no more than 0.05% (excluding 0%), and N: no more than 0.04% (excluding 0%), with the remainder being iron and inevitable impurities and the amount of dissolved nitrogen in the steel being no less than 0.006%.

Abstract: A power transmission shaft having an improved strength and ensuring a stable torsion fatigue strength. The power transmission shaft has coupling members respectively provided on the opposite ends of an pipe part made of a steel material. The steel material includes 0.30-0.45% by weight of C, 0.05-0.35% by weight of Si, 1.0-2.0% by weight of Mn, 0.05% by weight or less of Al, 0.01% by weight or less of S, and the remainder (iron Fe and unavoidable impurities). The pipe part has an electro-unite portion that extends in the axial direction. The electro-unite portion and neighborhood thereof are hardened so as to have a Rockwell hardness HRC of 45 or more. Also, another power transmission shaft has coupling members integrally formed on opposite ends thereof. In addition, the shaft is formed from a steel element tube by a plastic working.

Abstract: An austenitic stainless steel with a composition comprising: at most 0.15% of C; 2% to 10% of Mn; at most 2% of Ni; at most 4% of Cu; 0.1% to 0.4% of N; 10% to 20% of Cr; at most 1% of Si; at most 3% of Mo; and at most 0.7% of Ti; is used to manufacture equipment, for example furnaces, reactors or ducts, or elements of this equipment, or to coat the internal walls of this equipment, said equipment being used to implement petrochemical processes conducted at temperatures of 350° C. to 1100° C. and in which coke can be formed.

Abstract: A case hardening steel having good-grain coarsening prevention properties during carburization. The steel comprises, by weight, 0.1 to 0.4%. C, 0.02 to 1.3% Si, 0.3 to 1.8% Mn, 0.001 to 0.15% S, 0.015 to 0.04% Al, 0.005 to 0.04% Nb, 0.006 to 0.020% N, one, two or more selected from 0.4 to 1.8% Cr, 0.02 to 1.0% Mo, 0.1 to 3.5% Ni, 0.03 to 0.5% V, and in which P is limited to not more than 0.025%, Ti is limited to not more than 0.010%, and O is limited to not more than 0.0025%, with the balance being iron and unavoidable impurities, the steel being characterized in that, following hot rolling, the steel has a Nb(CN) precipitation amount of not less than 0.005% and an AlN precipitation amount that. is limited to not more than 0.005%.

Abstract: A steel tube having a composition which contains: 0.05 to 0.30% of C; 1.8 to 4.0% of Mn; Si; and Al is subjected to a diameter-reducing rolling process in which the total diameter-reduction rate is no less than 20% and the temperature at which the diameter-reducing rolling process is finished is no higher than 800 ° C., whereby a structure constituted of martensite and/or bainite or further of ferrite is obtained as a transformation product from the deformed &ggr;. As a result, a steel tube having tensile strength of 1000 MPa or more and excellent three-point-bending property can be obtained. The composition of the steel tube of the present invention may further include at least one type of element selected from the group consisting of Cu, Ni, Cr and Mo, or at least one type of element selected from the group consisting of Nb, V, Ti and B, or at least of one type selected from the group consisting of REM and Ca.

Abstract: Process for producing a drawn wire, in particular a wire for reinforcing tires, having a diameter of less than 0.3 mm by drawing a base wire rod having a diameter of greater than 5 mm or a predrawn base wire made of steel with the following composition by weight: carbon≦40×10−3% nitrogen≦40×10−3%, the carbon and nitrogen satisfying the relationship C+N≦50×10−3%, 0.2%≦silicon≦1.0%, 0.2%≦manganese≦5%, 9%≦nickel≦12%, 15%≦chromium≦20%, 1.5%≦copper≦4%, sulfur≦10×10−3%, phosphorus<0.050%, 40×10−4%≦total oxygen≦120×10−4%, 0.1×10−4%≦aluminum≦20×10−4%, magnesium≦5×10−4%, 0.