Abstract: A low carbon-high manganese steel sheet and process for manufacturing the sheet is provided. The process includes soaking a steel slab with a desired chemical composition within a temperature range of 1200-1350° C., followed by hot rolling of the slab into hot strip. The cold rolled sheet is continuously annealed within a temperature range of 730-850° C. and temper rolled between 1.0-2.0%. The temper rolled sheet has a yield strength greater than 280 megapascals (MPa), a tensile strength greater than 400 MPa, an elongation to fracture greater than 30%, an n-value greater than 0.15, and a bakehard index between 15-35 MPa.

Abstract: A high strength-high ductility cold rolled steel sheet is provided. The steel sheet has a recovery annealed microstructure, a yield strength greater than 820 megapascals (MPa) and a percent elongation to failure greater than 3.5%. In some instances, the steel alloy sheet has a Rockwell B hardness greater than 100 and may or may not exhibit a yield strength-to-tensile strength ratio between 0.25 and 1.00.

Abstract: A non-oriented electrical steel sheet containing: in mass %, C: 0.005% or less; Si: 0.1% to 2.0%; Mn: 0.05% to 0.6%; P: 0.100% or less; and Al: 0.5% or less, in which 10 pieces/?m3 or less in number density of non-magnetic precipitate AlN having an average diameter of 10 nm to 200 nm are contained, and an average magnetic flux density B50 in a rolling direction and in a direction perpendicular to rolling is 1.75 T or more. This non-oriented electrical steel sheet can be manufactured by two methods of a method of performing hot rolling annealing at a temperature of 750° C. to an Ac1 transformation point and a method of setting a coil winding temperature to 780° C. or higher and performing self annealing.

Abstract: The present invention provides a high-strength steel sheet excellent in shape fixability. The high-strength steel sheet contains C, Si, Mn, P, S, Al, N, and O with predetermined contents, in which a retained austenite phase of 5 to 20% in volume fraction is contained, an amount of solid-solution C contained in the retained austenite phase is 0.80 to 1.00% in mass %, WSi? is 1.10 times or more WSi*, WMn? is 1.10 times or more WMn*, and when a frequency distribution is measured with respect to a sum of a ratio between WSi and WSi* and a ratio between WAl and WAl*, a mode value of the frequency distribution is 1.95 to 2.05, and a kurtosis is 2.00 or more.

Abstract: A method for producing a high-tensile cold-rolled steel sheet includes subjecting a slab having a composition containing C: more than 0.020% and less than 0.30%, Si: more than 0.10% and 3.00% or less, and Mn: more than 1.00% and 3.50% or less to hot rolling wherein the roll draft of the final one pass is higher than 15%, and rolling is finished in the temperature region of Ar3 point or higher, optionally annealing wherein the hot-rolled steel sheet is heated to 300° C. or higher after being cooled to 780° C. or lower, coiling higher than 400° C. or lower than 400° C., cold rolling the hot-rolled steel sheet or the annealed steel sheet, and annealing wherein the cold-rolled steel sheet is soaked in the temperature region of (Ac3 point?40° C.) or higher, cooling to 500° C. or lower and 300° C. or higher, and holding in that temperature region for 30 seconds or longer.

Abstract: A high strength pressed member has excellent ductility and stretch flangeability and tensile strength of 780-1400 MPa, with a predetermined steel composition and steel microstructure relative to the entire microstructure of steel sheet, where area ratio of martensite 5-70%, area ratio of retained austenite 5-40%, area ratio of bainitic ferrite in upper bainite 5% or more, and total thereof is 40% or more, 25% or more of martensite is tempered martensite, polygonal ferrite area ratio is above 10% and below 50% to the entire microstructure of steel sheet, and average grain size is 8 ?m or less, average diameter of a group of polygonal ferrite grains is 15 ?m or less, the group of polygonal ferrite grains represented by a group of ferrite grains of adjacent polygonal ferrite grains, and average carbon content in retained austenite is 0.70 mass % or more and tensile strength is 780 MPa or more.

Abstract: A method for manufacturing the high strength steel sheet having excellent formability includes hot-rolling a steel slab having a chemical composition containing, by mass %, C: 0.03% or more and 0.35% or less, Si: 0.5% or more and 3.0% or less, Mn: 3.5% or more and 10.0% or less, P: 0.1% or less, S: 0.01% or less, N: 0.008% or less and the balance comprising Fe and inevitable impurities, coiling the hot-rolled steel sheet at a temperature range of the Ar1 transformation point to the Ar1 transformation point+(the Ar3 transformation point?the Ar1 transformation point)/2, cooling the coiled steel sheet down to 200° C. or lower, heating and holding the cooled steel sheet at a temperature range of the Ac1 transformation point?200° C.

Abstract: A method for producing a grain-oriented electrical steel strip or sheet, in which the slab temperature of a thin slab consisting of a steel having (% wt.) Si: 2-6.5%, C: 0.02-0.15%, S: 0.01-0.1%, Cu: 0.1-0.5%, wherein the Cu to S content ratio is % Cu/% S>4, Mn: up to 0.1%, wherein the Mn to S content ratio is % Mn/% S<2.5, and optional contents of N, Al, Ni, Cr, Mo, Sn, V, Nb, is homogenised to 1000-1200° C. The thin slab is hot rolled into a hot strip having a thickness of 0.5-4.0 mm at an initial hot-rolling temperature of <=1030° C. and a final hot-rolling temperature of >=710° C., with a thickness reduction in the first and in the second hot-forming passes of >=40%. The hot strip is cooled, coiled, and cold rolled into a cold strip having a final thickness of 0.15-0.50 mm. An annealing separator is applied onto the annealed cold strip to form a Goss texture.

Abstract: A low specific gravity and high strength steel sheet includes C of 0.2% to 0.8%, Mn of 2% to 10%, P of 0.02% or less, S of 0.015% or less, Al of 3% to 15%, and N of 0.01% or less. A ratio of Mn/Al is 0.4 to 1.0. Retained austenite in a structure is included in the range of 1% or more. The steel sheet further includes one or two or more elements selected from the group consisting of Si of 0.1% to 2.0%, Cr of 0.1% to 0.3%, Mo of 0.05% to 0.5%, Ni of 0.1% to 2.0%, Cu of 0.1% to 1.0%, B of 0.0005% to 0.003%, Ti of 0.01% to 0.2%, Zr of 0.005% to 0.2%, Nb of 0.005% to 0.2%, W of 0.1% to 1.0%, Sb of 0.005% to 0.2%, and Ca of 0.001% to 0.2%.

Abstract: A method for manufacturing a high-strength steel sheet for a can, including (a) hot rolling a steel slab at a slab extraction temperature of 1200° C. or more and a finish rolling temperature of (Ar3 transformation temperature?30)° C. or more, the steel slab containing, on the basis of mass percent, more than 0.02%, but 0.10% or less of C, 0.10% or less of Si, 1.5% or less of Mn, 0.20% or less of P, 0.20% or less of S, 0.10% or less of Al, 0.0120% to 0.0250% of N, and the balance being Fe and incidental impurities; (b) coiling at a temperature of 650° C. or less; (c) pickling; (d) carrying out a first cold rolling; (e) continuously annealing; and (f) carrying out a second cold rolling at a reduction ratio of 10% or more and less than 20%.

Abstract: High strength steel sheet which secures tensile maximum strength 900 MPa or more high strength while having excellent shapeability, which high strength steel sheet which is excellent in shapeability characterized by having a predetermined composition of ingredients, by the steel sheet structure including a ferrite phase and martensite phase, by the ratio of Cu particles incoherent with the bcc iron being 15% or more with respect to the Cu particles as a whole, by a density of Cu particles in the ferrite phase being 1.0×1018/m3 or more, and by an average particle size of Cu particles in the ferrite phase being 2.0 nm or more.

Abstract: A process for manufacturing a cold rolled high strength dual phase steel. The process includes soaking a steel slab within a temperature range of 1200-1300° C., hot rolling the soaked steel slab in a roughing treatment and producing a transfer bar, and hot rolling the transfer bar in a finishing treatment and producing hot rolled strip. The hot rolled strip is cold rolled with at least a 55% reduction in thickness. The cold rolled sheet is intercritically annealed at a temperature between 790-840 ° C. and rapidly cooled to a temperature between 450-500 ° C. The rapidly cooled sheet has a ferrite plus martensite microstructure, a 0.2% yield strength of at least 550 MPa, a tensile strength of at least 980 MPa and a total elongation to failure of at least 10%.

Abstract: High strength steel sheet and high strength galvanized steel sheet which are excellent in shapeability which secure a tensile maximum strength 900 MPa or more high strength while obtaining excellent ductility and stretch flangeability, which sheets have predetermined compositions of ingredients, have steel sheet structures which contain volume fraction 1 to 20% of residual austenite phases, and which have martensite transformation points of the residual austenite phases of ?60° C. or less.

Abstract: The present invention relates to a hot press forming steel plate made of a composition comprising: 0.3-1.0 wt % of C; 0.0-4.0 wt % of Mn; 1.0-2.0 wt % of Si; 0.01-2.0 wt % of Al; 0.015 wt % or less of S; 0.01 wt % or less of N; and the remainder being Fe and unavoidable impurities. Further, the present. invention relates to a method for manufacturing the hot press forming steel plate, characterized by comprising the steps of: heating, to between 1100 and 1300° C., a steel slab having the composition; performing hot rolling finishing between. an Ar3 transformation point and 950° C.; and performing winding between MS and 720° C. Further, the present invention. relates to a hot press formed member characterized by having the composition, and having a dual phase microstructure made of bainite and residual austenite.

Abstract: Dual-phase steels and a process for producing a family of dual-phase steels that have a low YS/TS ratio and tensile strength above 590 MPa. The process includes employing low annealing temperatures combined with specific cooling strategies using gas jet rapid cooling equipped with “Ultra Rapid Cooling” (URC) capacity in the cooling tower. The process can also include the production of dual-phase steels with tensile strengths of at least 690 MPa by processing steels with specific cooling strategies using the URC having a refined Mo content towards the higher end of the chemical composition range mentioned in the current stated invention.

Abstract: The present disclosure relates to a high strength steel sheet having good wettability, a tensile strength of 590 MPa or more and a strength-ductility balance (TS×El) of 16,520 MPa·% or more, and a manufacturing method thereof. The high strength steel comprises, in % by weight, C: 0.03˜0.1%, Si: 0.005˜0.105%, Mn: 1.0˜3.0%, P: 0.005˜0.04%, S: 0.003% or less, N: 0.003˜0.008%, Al: 0.05˜0.4%, Mo or Cr satisfying the inequality 10?50·[Mo %]+100·[Cr %]?30, at least one of Ti: 0.005˜0.020%, V: 0.005˜0.050% and B: 0.0005˜0.0015%, and the balance of Fe and unavoidable impurities, wherein a microstructure of the steel sheet is a multi-phase structure comprising, in an area ratio of cross-sectional structure, 70% or more ferrite phase having a Vickers hardness Hv of 120˜250 and 10% or more martensite phase having a Vickers hardness Hv of 321˜555.

Abstract: A high strength mild steel alloy is provided. In addition, a process for making the high strength steel alloy is also provided. The process includes providing a mild steel alloy with a chemical composition in weight percent within a range of 0.12-0.25 carbon, 0.30-1.70 manganese, 0.50 max silicon, 0.10 max chromium, 0.01 max niobium, 0.035 max titanium, 0.01 vanadium, 0.10 max molybdenum, 0.10 max nickel, 0.015 max sulfur, 0.025 max phosphorus, 0.012 max nitrogen, 0.003 max boron, and 0.015-0.065 aluminum. Hot rolled steel strip with a thickness of less than 10 millimeters is cold rolled to produce a cold rolled steel sheet that has a thickness that is less than 50% of the hot rolled steel strip thickness which is subsequently recovery annealed to provide sheet material having a yield strength greater than 550 megapascals (MPa) and a percent elongation to failure greater than 3.5%.

Abstract: A steel sheet having a composition containing C: 0.20% to 0.50%, Si: 1.0% or less, Mn: 2.0% or less, P: 0.03% or less, S: 0.02% or less, sol.Al: 0.08% or less, N: 0.02% or less, and Fe and incidental impurities, and a microstructure composed of ferrite and cementite, wherein each of the average grain size ds of the ferrite in the region from the surface of the steel sheet to the position at one-quarter of the sheet thickness and the average grain size dc of the ferrite in the region from the position at one-quarter of the sheet thickness of the steel sheet to the sheet thickness center is 20 to 40 ?m, 0.80?ds/dc?1.20 is satisfied, the average grain size of the cementite is 1.0 ?m or more, the spheroidizing ratio is 90% or more, and 90% or more of cementite is present inside ferrite grains.

Abstract: The present invention is related to a rolled steel sheet suitable for enamelling, said sheet having a carbon profile, defined by a gradient in the C-level from a level Csurface at at least one surface of the sheet, to a level Cbulk in the bulk of the sheet, Cbulk being higher than Csurface, and with: Cbulk higher than 0 and lower than or equal to 0.08 wt %, Csurface between 0 and 0.015 wt %, Al between 0.012 wt % and 0.07 wt %, Mn between 0.12 wt % and 0.45 wt %, O lower than 0.01 wt % and optionally: Cu between 0.025 wt % and 0.1 wt %, S between 0.008 wt % and 0.04 wt %, Ca between 0.0005 wt % and 0.005 wt %, the balance being Fe and incidental impurities, and wherein the depth where the C-level reaches Cbulk+Csurface)/2, is higher than 75 ?m. The invention is equally related to a method for producing said steel sheet.

Abstract: A non-oriented electrical steel sheet contains 2.8 mass % or more and 4.0 mass % or less of Si, 0.2 mass % or more and 3.0 mass % or less of Al, and 0.02 mass % or more and 0.2 mass % or less of P. The non-oriented electrical steel sheet contains further contains 0.5 mass % or more in total of at least one kinds selected from a group consisting of 4.0 mass % or less of Ni and 2.0 mass % or less of Mn. A C content is 0.05 mass % or less, a N content is 0.01 mass % or less, an average grain diameter is 15 ?m or less, and a <111> axial density is 6 or larger.

Abstract: The present invention provides ferritic stainless steel sheet which is excellent in heat resistance at 950° C. and workability at ordinary temperature, that is, ferritic stainless steel sheet excellent in heat resistance and workability which is characterized by containing, by mass %, C: 0.02% or less, N: 0.02% or less, Si: over 0.1 to 1.0%, Mn: 0.5% or less, P: 0.020 to 0.10%, Cr: 13.0 to 20.0%, Nb: 0.5 to 1.0%, Cu: 1.0 to 3.0%, Mo: 1.5 to 3.5%, W: 2.0% or less, B: 0.0001 to 0.0010%, and Al: 0.01 to 1.0% and having a balance of Fe and unavoidable impurities, where Mo+W is made 2.0 to 3.5%.

Abstract: Provided are a high-strength cold-rolled steel sheet having excellent formability, excellent ductility, excellent hole expansibility, and high yield ratio and a method for producing the same. The high-strength cold-rolled steel sheet contains 0.05% to 0.15% C, 0.10% to 0.90% Si, 1.0% to 2.0% Mn, 0.005% to 0.05% P, 0.0050% or less S, 0.01% to 0.10% Al, 0.0050% or less N, and 0.010% to 0.100% Nb, which are chemical components, on a mass basis, the balance being Fe and unavoidable impurities; has a microstructure which is a multi-phase structure containing 90% or more of a ferrite phase and 0.5% to less than 5.0% of a martensite phase on a volume fraction basis, the remainder being low-temperature transformation phases; and has a yield ratio of 70% or more.

Abstract: This hot-rolled ferritic stainless steel sheet has a steel composition containing, in terms of % by mass: 0.02% or less of C; 0.02% or less of N; 0.1% to 1.5% of Si; 1.5% or less of Mn; 0.035% or less of P; 0.010% or less of S; 1.5% or less of Ni; 10% to 20% of Cr; 1.0% to 3.0% of Cu; 0.08% to 0.30% of Ti; and 0.3% or less of Al, with the balance being Fe and unavoidable impurities, and the hot-rolled ferritic stainless steel sheet has a Vickers hardness of less than 235 Hv.

Abstract: The present invention provides a method for manufacturing a hot stamped body, the method including: a hot-rolling step; a coiling step; a cold-rolling step; a continuous annealing step; and a hot stamping step, in which the continuous annealing step includes a heating step of heating the cold-rolled steel sheet to a temperature range of equal to or higher than Ac1° C. and lower than Ac3° C.; a cooling step of cooling the heated cold-rolled steel sheet from the highest heating temperature to 660° C. at a cooling rate of equal to or less than 10° C./s; and a holding step of holding the cooled cold-rolled steel sheet in a temperature range of 550° C. to 660° C. for one minute to 10 minutes.

Abstract: Provided is an austenitic, lightweight, high-strength steel sheet having a high yield ratio and ductility and a method for producing the same, and more particularly, to a high-strength steel sheet for automotive interior panels, exterior panels, and structural parts, and a method for producing the steel sheet. The steel sheet may be a hot-rolled steel sheet, a cold-rolled steel sheet, or a plated steel sheet. The steel sheet includes, by weight %, C: 0.6% to 1.0%, Si: 0.1% to 2.5%, Mn: 10% to 15%, P: 0.02% or less, S: 0.015% or less, Al: 5% to 8%, Ti: 0.01% to 0.20%, N: 0.02% or less, and the balance of Fe and inevitable impurities, wherein the steel sheet has a specific gravity of 7.4 g/cm3 and a Mn/Al ratio of 2 to 3.

Abstract: A high-strength, high-workability steel sheet for cans contains 0.070% to less than 0.080% C, 0.003% to 0.10% Si, 0.51% to 0.60% Mn, and the like on a mass basis and has a tensile strength of 500 MPa or more and a yield elongation of 10% or more. The average size and elongation rate of crystal grains are 5 ?m or more and 2.0 or less, respectively, in cross section in the rolling direction thereof. The hardness difference obtained by subtracting the average Vickers hardness of a cross section ranging from a surface to a depth equal to one-eighth of the thickness of the sheet from the average Vickers hardness of a cross section ranging from a depth equal to three-eighths of the sheet thickness to a depth equal to four-eighths of the sheet thickness is 10 points or more and/or the maximum Vickers hardness difference is 20 points or more.

Abstract: A method for manufacturing a precipitation hardening cold-rolled steel sheet with an excellent yield ratio. The method may include the steps of hot rolling a steel slab with finish rolling at a temperature of Ar3 transformation point or more to form a hot-rolled steel sheet, coiling the hot-rolled steel sheet at a temperature of 550-600 ° C., cold rolling the hot-rolled steel sheet at a reduction ratio of 50% or more; and recovery-recrystallization annealing the cold-rolled steel sheet at a line speed of 150-200 mpm and at a temperature of 780-820° C. in a continuous annealing furnace. The recovery-recrystallization annealing may provide a recrystallization ratio of 65-75%. The steel slab includes, by weight %: C: 0.07-0.10%, Mn: 1.41-1.70%, P: 0.05-0.07%, S: 0.005% or less, N: 0.005% or less, acid-soluble Al: 0.10-0.15%, Nb: 0.06-0.09%, B: 0.0008-0.0012%, Sb: 0.02-0.06%, and the balance comprising Fe and other unavoidable impurities.

Abstract: It is an object of the present invention to provide a high strength cold-rolled steel sheet, which has superior bake hardenability, aging resistance at room temperature and secondary work embrittlement resistance, and a method for manufacturing the same. The steel sheet has a grain size of ASTM No. of 9 or more after annealing, a BH of 30 MPa or more, an AI of 30 MPa or less, and a tensile strength of 340˜390 MPa through appropriate control of solute elements in steel by addition of a small amount of Ti, addition of Al and Mo, and control of manufacturing conditions, and refinement of crystal grains after annealing. The cold-rolled steel sheet and the galvannealed steel sheet produced using the cold-rolled steel sheet have the superior bake hardenability, aging resistance at room temperature, and secondary work embrittlement resistance.

Abstract: The present invention provides a method for manufacturing a hot stamped body having a vertical wall, the method including: a hot-rolling step; a coiling step; a cold-rolling step; a continuous annealing step; and a hot stamping step, in which the continuous annealing step includes a heating step of heating the cold-rolled steel sheet to a temperature range of equal to or higher than Ac1° C. and lower than Ac3° C.; a cooling step of cooling the heated cold-rolled steel sheet from the highest heating temperature to 660° C. at a cooling rate of equal to or less than 10° C./s; and a holding step of holding the cooled cold-rolled steel sheet in a temperature range of 550° C. to 660° C. for one minute to 10 minutes.

Abstract: Provided is a method of manufacturing a high-carbon hot-rolled steel sheet, including the steps of i) preparing high-carbon steel materials comprising C: 0.7 to 0.9%, Si: 0.5% or less, Mn: 0.1 to 1.5%, Cr: 0.5% or less, P: 0.05% or less, and S: 0.03% or less in wt % and remaining Fe and other inevitable impurities; ii) heating the high-carbon steel materials again and manufacturing a steel sheet by performing hot rolling in an austenite region in which a finishing temperature for the hot rolling is an Ar3 transformation temperature or higher; iii) rapidly cooling the steel sheet at 520 to 620° C. before phase transformation is started in a Run-Out Table (ROT); iv) uniformly maintaining a cooling retention temperature so that the cooled steel sheet is subject to phase transformation in any one temperature between 520 to 620° C.; and v) winding the steel sheet in the cooling retention temperature. Also provided is the high-carbon steel sheet made by the above-described method.

Abstract: A steel sheet for enameling for eliminating surface defects such as fish scale defects and having excellent formability, and provides a steel sheet for enamel having no surface defects, including: more than 0 wt % and 0.005 wt % or less of C, 0.1 to 0.5 wt % of Mn, more than 0 wt % and 0.03 wt % or less of Si, 0.05 to 0.3 wt % of Cr, more than 0 wt % and 0.03 wt % or less of Al, 0.03 to 0.1 wt % of O, more than 0 wt % and 0.03 wt % or less of P, more than 0 wt % and 0.02 wt % or less of S, more than 0 wt % and 0.015 wt % or less of Cu, more than 0 wt % and 0.005 wt % or less of N, Fe in a remaining content, and other inevitable impurities.

Abstract: The present disclosure relates to a dual phase steel sheet and a method of manufacturing the same. The steel sheet comprises C: 0.05˜0.10% wt %, Si: 0.03˜0.50 wt %, Mn: 1.50˜2.00 wt %, P: greater than 0 wt %˜0.03 wt %, S: greater than 0 wt %˜0.003 wt %, Al: 0.03˜0.50 wt %, Cr: 0.1˜0.2 wt %, Mo: 0.1˜0.20 wt %, Nb: 0.02˜0.04 wt %, B: greater than 0 wt %˜0.005 wt %, N: greater than 0 wt %˜0.01 wt %, and the balance of Fe and other unavoidable impurities. To impart excellent formability, bake hardenability, dent resistance, high Ri value and plating characteristics to the steel sheet for exterior and interior panels of automobiles, the steel sheet is processed to have a dual phase structure through cold rolling, annealing, and hot-dip galvanizing.

Abstract: A method for manufacturing a fine spheroidized steel sheet having an excellent heat treatment characteristic, the method including: i) manufacturing a high carbon slab that is formed of 0.3 to 1.0 wt % C, 0.1 to 1.2 wt % Mn, 0 to 0.4 wt % Si, 0.01 to 0.1 wt % Al, 0 to 0.01 wt % S, and balance Fe and an inevitably added impurity as residuals; ii) reheating the slab to a temperature of Ar3 transformation point or more; iii) roughing rolling the slab, and manufacturing a thin plate by performing finish rolling in an austenite region; iv) cooling the thin plate at a cooling speed of 50 to 300° C./sec; v) finishing the cooling of the thin plate at a temperature region of 400 to 650° C. and maintaining the temperature; vi) winding the thin plate at a temperature region of 450 to 700° C.; vii) performing cold rolling at a reduction ratio of 30% or more; and viii) spheroidizing annealing the cold rolled thin plate.

Abstract: A high tensile-strength galvanized steel sheet includes C: at least 0.05% but less than 0.12%, Si: at least 0.01% but less than 0.35%, Mn: 2.0% to 3.5%, P: 0.001% to 0.020%, S: 0.0001% to 0.0030%, Al: 0.005% to 0.1%, N: 0.0001% to 0.0060%, Cr: more than 0.5% but not more than 2.0%, Mo: 0.01% to 0.50%, Ti: 0.010% to 0.080%, Nb: 0.010% to 0.080%, and B: 0.0001% to 0.0030%, the remainder being Fe and unavoidable impurities, wherein the high tensile-strength galvanized steel sheet has a microstructure that contains 20% to 70% by volume ferrite having an average grain size of 5 ?m or less. The high tensile-strength galvanized steel sheet has a tensile strength of at least 980 MPa, and excellent formability and weldability.

Abstract: A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 ?m to 1 ?m, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.

Abstract: A method provides a slab by continuous casting of a steel having a component composition of, in mass %, C: 0.005% or less, Mn: 0.05 to 0.5%, Al: 0.01 to 0.10%, N: 0.0010 to 0.0070%, B: 0.15×N to 0.75×N (0.15 to 0.75 in terms of B/N), and one or both of Nb: 4×C to 20×C (4 to 20 in terms of Nb/C) and Ti: 2×C to l0×C (2 to 10 in terms of Ti/C), and the balance of Fe and inevitable impurity elements; rough rolling the slab; finish rolling the rough-rolled slab wherein 5% or more and less than 50% of the total amount of rolling reduction in the finish rolling is hot-rolled at a temperature lower than the Ar3 transformation point; winding the hot-rolled steel sheet at a winding temperature of 640 to 750 ° C.; pickling the coiled steel sheet; cold rolling the pickled steel sheet at a rolling reduction rate of 88 to 96%; and annealing the cold-rolled steel sheet in a temperature range of higher than 400 ° C. to a temperature that is 20 ° C. lower than the recrystallization temperature.

Abstract: The stainless steel sheet according to the present invention is a ferritic stainless steel which is comprised of, by mass %, C: 0.001 to 0.03%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.5%, P: 0.005 to 0.05%, S: 0.0001 to 0.01%, Cr: 12 to 16%, N: 0.001 to 0.03%, Nb: 0.05 to 0.3%, Ti: 0.03 to 0.15%, Al: 0.005 to 0.5%, Sn: 0.01 to 1.0%, and has the remainder of Fe and unavoidable impurities and satisfies the relationship of 1?Nb/Ti?3.5. The method comprises heating a slab of stainless steel which contains the above steel ingredients, setting the extraction temperature 1080 to 1190° C., and setting the coiling temperature after the end of hot rolling 500 to 700° C. After hot rolling, the method comprises annealing the hot rolled sheet, which can be omitted, cold rolling once or cold rolling twice or more which includes processing annealing, and finish annealing the steel sheet at 850 to 980° C.

Abstract: A steel sheet, including: as chemical components, by mass %, 0.05% to 0.35% of C; 0.05% to 2.0% of Si; 0.8% to 3.0% of Mn; 0.01% to 2.0% of Al; equal to or less than 0.1% of P; equal to or less than 0.05% of S; equal to or less than 0.01% of N; and the balance including iron and inevitable impurities, wherein an area ratio of equal to or higher than 50% of a total of a ferrite phase, a bainite phase, and a tempered martensite phase is contained, an area ratio of equal to or higher than 3% of a retained austenite phase is contained, and crystal grains of the retained austenite phase having a number ratio of equal to or higher than 50% satisfy Expression 1, assuming carbon concentration at a position of center of gravity is Cgc and a carbon concentration at a grain boundary is Cgb.

Abstract: Provided is a steel sheet having excellent surface roughening resistance and a manufacturing method thereof. The steel sheet for cans contains 0.0040 to 0.01% C and 0.02 to 0.12% Nb. An average ferrite grain size in a cross section in the rolling direction in a region ranging from a surface layer of the steel sheet to a position ¼ of a sheet thickness away from the surface layer of the steel sheet is set to 7 ?m or more and 10 ?m or less, and the average ferrite grain size in a cross section in the rolling direction in a region ranging from the position ¼ of a sheet thickness away from the surface layer of the steel sheet to a sheet thickness center portion of the steel sheet is set to 15 ?m or less.

Abstract: The present disclosure relates to a dual phase steel sheet and a method of manufacturing the same. The steel sheet comprises C: 0.05˜0.10 % wt %, Si: 0.03˜0.50 wt %, Mn: 1.50˜2.00 wt %, P: greater than 0 wt %˜0.03 wt %, S: greater than 0 wt %˜0.003 wt %, Al: 0.03˜0.50 wt %, Cr:0.1˜0.2 wt %, Mo: 0.1˜0.20 wt %, Nb: 0.02˜0.04 wt %, B: greater than 0 wt %˜0.005 wt %, N: greater than 0 wt %˜0.01 wt %, and the balance of Fe and other unavoidable impurities. To impart excellent formability, bake hardenability, dent resistance, high Ri value and plating characteristics to the steel sheet for exterior and interior panels of automobiles, the steel sheet is processed to have a dual phase structure through cold rolling, annealing, and hot-dip galvanizing.

Abstract: A high strength steel sheet excellent in formability which has a chemical composition in mass %: C: 0.03 to 0.20%, Si: 0.005 to 0.3%, Mn: 1.0 to 3.1%, P: 0.001 to 0.06%, S: 0.001 to 0.01%, N: 0.0005 to 0.01%, Al: 0.2 to 1.2%, Mo?0.5%, and the balance: Fe and inevitable impurities, with the proviso that the values of mass % for Si and Al satisfy the following formula (1): (0.0012×[objective value of TS]?0.29?[Si])/2.45<Al<1.5?3×[Si]??(1) wherein [objective value of TS] represents a design strength value for the steel sheet in an Mpa unit, and has a metal structure containing ferrite and martensite. The above high strength steel sheet is also excellent in formability and the capability of being chemically treated and that of being hot-dip zinc sheeted.

Abstract: The present invention provides high strength thin-gauge steel sheet with excellent elongation and hole expandability having a tensile strength of 500 MPa or more and a method of production of high strength thin-gauge steel sheet with excellent elongation and hole expandability enabling production of this on an industrial scale, that is, high strength thin-gauge steel sheet comprised of, by mass %, C: 0.03 to 0.25%, Si: 0.013 to 0.299%, Mn: 0.8 to 3.1%, P?0.02%, S?0.02%, Al?2.0%, N?0.01%, and a balance of Fe and unavoidable impurities and having a microstructure comprised of ferrite with an area fraction of 10 to 85% and residual austenite with a volume fraction of 1 to 10%, an area fraction of 10% to 60% of tempered martensite, and a balance of bainite.

Abstract: A cold-rolled steel sheet for outer panels and the like of an automobile body, a galvannealed steel sheet using the cold-rolled steel sheet, and a method for manufacturing the same are disclosed. It is an object of the present invention to provide a high strength cold-rolled steel sheet, which has superior bake hardenability, aging resistance at room temperature and secondary work embrittlement resistance, and a method for manufacturing the same. The steel sheet has a grain size of ASTM No. of 9 or more after annealing, a BH of 30 MPa or more, an AI of 30 MPa or less, and a tensile strength of 340˜390 MPa through appropriate control of solute elements in steel by addition of a small amount of Ti, addition of Al and Mo, and control of manufacturing conditions, and refinement of crystal grains after annealing.

Abstract: The present invention is related to a process comprising a cold rolling step, for the production of uncoated, electro-galvanised or hot dip galvanised TRIP steel products, hot rolling a slab of a specific composition, wherein the finishing rolling temperature is higher than the Ar3 temperature, to form a hot-rolled substrate, cooling said substrate to a coiling temperature (CT) between 500° C. and 680° C., coiling said substrate at said coiling temperature, pickling said substrate to remove the oxides, cold rolling said substrate to obtain a reduction of thickness, with a minimum reduction of 40%.

Abstract: A slab having a predetermined composition is heated to 1280° C. or more. The slab is hot-rolled to obtain a hot-rolled steel sheet. The hot-rolled steel sheet is annealed to obtain an annealed steel sheet. The annealed steel sheet is cold-rolled to obtain a cold-rolled steel sheet. The cold-rolled steel sheet is decarburization annealed to obtain a decarburization annealed steel sheet. The decarburization annealed steel sheet is coiled in a coil state. The coil-state decarburization annealed steel sheet is finish-annealed. The cold-rolled steel sheet is heated to a temperature of 800° C. or more at a rate of 30° C./sec or more and 100° C./sec or less during increasing temperature of the cold-rolled steel sheet in the decarburization annealing or before the decarburization annealing. The decarburization annealed steel sheet is heated at a rate of 20° C./h or less within a temperature range of 750° C. or more and 1150° C.

Abstract: The invention provides a carbon steel sheet including C: 0.20% to 0.45% by mass, Si: 0.05% to 0.8% by mass, Mn: 0.85% to 2.0% by mass, P: 0.001% to 0.04% by mass, S: 0.0001% to 0.006% by mass, Al: 0.01% to 0.1% by mass, Ti: 0.005% to 0.3% by mass, B: 0.0005% to 0.01% by mass and N: 0.001% to 0.01% by mass, in which a K value that can be obtained from 3C+Mn+0.5Si is greater than or equal to 2.0; surface hardness is less than or equal to 77 on the Rockwell B Scale; and the average content of N in a zone from the surface to a depth of 100 ?m is less than or equal to 100 ppm. This carbon steel sheet is configured to be carburized in a carburization atmosphere with a carbon potential of 0.6 or less.

Abstract: A cold-rolled steel sheet with excellent bending workability has a component composition of 0.025% or less C, 0.1% or less Si, 0.05% to 0.5% Mn, 0.03% or less P, 0.02% or less S, and 0.01% to 0.1% sol. Al on a mass basis, the remainder being Fe and unavoidable impurities; a microstructure that is a ferrite rolling texture; a tensile strength TS of 390 MPa or more; a thickness of 0.4 mm or more; and a sheet thickness direction ultimate ductility of 1.3 or more, wherein the sheet thickness direction ultimate ductility is the natural logarithm Ln(t0/t1) of the ratio of the thickness t0 of an untested steel sheet to the thickness t1 of the fracture surface of the tested steel sheet as determined by a tensile test.

Abstract: A high strength cold rolled steel sheet excellent in weldability and has a TS of 440 MPa or more includes a composition including C: 0.0005 to 0.005%, Si: 0.1 to 1.0%, Mn: 1 to 2.5%, P: 0.01 to 0.2%, S: 0.015% or less, sol. Al: 0.05% or less, N: 0.007% or less, Ti: 0.01 to 0.1%, B: 0.0005 to 0.0020%, Cu: 0.05 to 0.5%, and Ni: 0.03 to 0.5% by mass with the balance Fe and incidental impurities; and a microstructure constituted by a ferrite single phase.

Abstract: A high carbon cold-rolled steel sheet having both excellent stretch-flange formability and excellent homogeneity of hardness in the sheet thickness direction is provided by a manufacturing method having the steps of: hot-rolling a steel containing 0.2 to 0.7% C by mass at finishing temperatures of (Ar3 transformation point ?20° C.) or above to prepare a hot-rolled sheet; cooling the hot-rolled sheet to temperatures of 650° C. or below at cooling rates from 60° C./s or larger to smaller than 120° C./s; coiling the hot-rolled sheet after cooling at coiling temperatures of 600° C. or below; cold-rolling the coiled hot-rolled sheet at rolling reductions of 30% or more to prepare a cold-rolled sheet; and annealing the cold-rolled sheet at annealing temperatures from 600° C. or larger to Ac1 transformation point or lower.

Abstract: The invention provides a steel sheet for hard tinplate and a TFS steel sheet each having an excellent formability and a temper grade of T4 to DR9, and an efficient manufacturing method capable of selectively manufacturing these steel sheets by using raw materials having the same composition, wherein, the steel sheet for hard tinplate and a TFS steel sheet having a temper grade of T4 to DR9 is manufactured from raw materials having the same composition by changing a reduction ratio of temper rolling or double reduce rolling for ultra-low carbon aluminum killed steel C and P contents of which are so regulated as to satisfy a specific formula <1>: 1.6×C×104+0.93×P×103?70??<1>.