Class / Patent application number | Description | Number of patent applications / Date published |
148533000 | Zinc(Zn), zinc base alloy or unspecified galvanizing | 72 |
20090025836 | Method Of Producing A Part With Very High Mechanical Properties From A Rolled Coated Sheet - The invention relates to a steel part coated with a compound consisting, over more than 90% of its thickness, of at least one Fe/Zn-based phase, the iron weight content of which is equal to 65% or higher and the Fe/Zn ratio of which is between 1.9 and 4, said compound being formed by at least one heat treatment for alloying between said steel and a precoat, said precoat consisting of a zinc alloy comprising, the contents being expressed by weight, between 0.5 and 2.5% aluminum and, optionally, one or more elements chosen from: Pb≦0.003%; Sb≦0.003%; Bi≦0.003%; 0.002%≦Si≦0.070%; La<0.05%; Ce<0.05%, the balance consisting of zinc and inevitable impurities. | 01-29-2009 |
20090065103 | METHOD AND APPARATUS FOR IMPROVED FORMABILITY OF GALVANIZED STEEL HAVING HIGH TENSILE STRENGTH - The present invention is directed to a method and apparatus of producing a dual-phase galvanized steel strip with improved formability while maintaining a high tensile strength. The present invention comprises a step of cooling and a step of reheating. In the cooling step, the galvanized steel strip has a temperature reduction of from about 300° C. to about 150° C.-250° C. This step of cooling should cool to a maximum extent of about 150° C. different between the initial temperature and the final temperature. This cooling may be accomplished by a hot water quench, or the use of a cooling tower, or other means. The step of reheating should follow the step of cooling. The step of reheating should heat the galvanized steel strip to a temperature of about 340°-390° C. This reheating causes the martensite in the galvanized steel strip to be tempered at a relatively low temperature, which reduces the Fe—Zn phase formation in the GI-coating. | 03-12-2009 |
20090139611 | Galvanized Steel Sheet and Method for Producing the Same - A galvanized steel sheet excellent in strength-ductility balance and bake-hardenability as well as a method for producing the same are provided. The chemical components thereof include C, Si, Mn, P, S, Al, N and Cr at content ratios of 0.005 to 0.04%, 1.5% or lower, 1.0 to 2.0%, 0.10% or lower, 0.03% or lower, 0.01 to 0.1%, less than 0.008% and 0.2 to 1.0%, respectively, with Mn (mass %)+1.29Cr (mass %) being in the range of 2.1 to 2.8, and further include iron and unavoidable impurities as the balance. The structure thereof consists of a ferrite phase and a martensite phase with a volume fraction being at least 3.0% and less than 10%, the average particle diameter of the ferrite is larger than 6 μm and not more than 15 μm, and 90% or more of the martensite phase exists in a ferrite grain boundary. In addition, in the production process of such a galvanized steel sheet, a steel sheet obtained in a cold rolling step is annealed at a temperature being at least the Ac1 point and not more than the Ac3 point. | 06-04-2009 |
20090151820 | Method of Production of Hot Dip Galvannealed Steel Sheet with Excellent Workability, Powderability, and Slidability - The present invention provides a method of production of hot dip galvannealed steel sheet with excellent workability compared with the Sendzimir method or non-oxidizing furnace method and further with excellent powdering or slidability, that is, a method of production of hot dip galvannealed steel sheet with excellent workability, powdering, and slidability characterized by processing a slab containing, by mass %, C: 0.01 to 0.12%, Mn: 0.05 to 0.6%, Si: 0.002 to 0.1%, P: 0.05% or less, S: 0.03% or less, sol. Al: 0.005 to 0.1%, and N: 0.01% or less and having a balance of Fe and unavoidable impurities by hot rolling, pickling, cold rolling, then annealing at 650 to 900° C., cooling to 250 to 450° C., holding at said temperature range for 120 seconds or more, then cooling to room temperature, pickling, preplating Ni or Ni—Fe without intermediate temper rolling, heating by 5° C./sec or more down to 430 to 500° C., galvanizing in a galvanization bath, wiping, then heating by a rate of temperature rise of 20° C./sec or more up to 460 to 550° C., not providing any soaking time or holding for soaking for less than 5 seconds, then cooling by 3° C./sec or more, and final temper rolling by a 0.4 to 2% elongation rate. | 06-18-2009 |
20090272467 | High-strength hot-dip galvanized steel sheet and hot-dip galvannealed steel sheet having fatigue resistance, corrosion resistance, ductility and plating adhesion, after severe deformation, and a method of producing the same - The present invention provides: a high-strength high-ductility hot-dip galvanized steel sheet and hot-dip galvannealed steel sheet having high fatigue resistance and corrosion resistance; a high-strength hot-dip galvanized steel sheet excellent in ductility, which improves non-plating defects and plating adhesion after severe deformation, and a method of producing the same; a high-strength and high-ductility hot-dip galvanized steel sheet having high fatigue resistance and corrosion resistance; a high-strength hot-dip galvanized steel sheet and hot-dip galvannealed steel sheet having superior appearance and workability, which suppresses the generation of non-plating defects, and a method of producing the same; and a high-strength hot-dip galvannealed steel sheet and a high-strength hot-dip galvanized steel sheet, which suppress non-plating defects and surface defects and have both corrosion resistance, in particular corrosion resistance in an environment containing chlorine ion, and high ductility, and a method of producing the same. | 11-05-2009 |
20100024925 | Steel Sheet Product Provided with an Anticorrosion Coating and Process for Producing It - A flat steel product, and a method for its production, which is formed from a steel substrate, such as strip or sheet steel, and a zinc-based corrosion protection coating, applied to at least one side of the steel substrate, which contains (in wt. %) Mg: 0.25 to 2.5%, Al: 0.2 to 3.0%, Fe: ≦4.0%, and optionally in total up to 0.8% of one or more elements of the group Pb, Bi, Cd, Ti, B, Si, Cu, Ni, Co, Cr, Mn, Sn and rare earths, remainder zinc and unavoidable impurities are described. The corrosion protection coating has an Al content of maximum 0.5 wt. % in an intermediate layer extending between a surface layer directly adjacent to the surface of the flat steel product and a border layer adjacent to the steel substrate and with a thickness amounting to at least 20% of the total thickness of the corrosion protection coating. | 02-04-2010 |
20100132849 | HIGH TENSILE-STRENGTH GALVANIZED STEEL SHEET AND PROCESS FOR MANUFACTURING HIGH TENSILE-STRENGTH GALVANIZED STEEL SHEET - 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 μm or less. The high tensile-strength galvanized steel sheet has a tensile strength of at least 980 MPa, and excellent formability and weldability. | 06-03-2010 |
20100132850 | HIGH STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR PRODUCING THE SAME - A high-strength hot-dip galvanized steel sheet that even on the premise of ordinary CGL heat cycle, has a low yield stress and excels in resistance to natural aging and baking hardenability without reliance on the use of expensive Mo; and a process for producing the same. The constituent composition thereof comprises 0.01 to less than 0.08% C, 0.2% or less Si, more than 1.0 to 1.8% Mn, 0.10% or less P, 0.03% or less S, 0.1% or less Al, 0.008% or less N and more than 0.5% Cr so that the relationship 1.95≦Mn(mass %)+1.3Cr(mass %)≦2.8 is satisfied and comprising the balance iron and unavoidable impurities. The structure thereof has a ferrite phase and a martensite phase of 2 to 15% area ratio, and the cumulative area ratio of pearlite phase and/or bainite phase is 1.0% or less. In the production of this hot-dip galvanized steel sheet, the temperature and cooling rate are controlled during the annealing/plating operation subsequent to cold rolling. | 06-03-2010 |
20100200126 | PRODUCTION FACILITY AND PRODUCTION PROCESS FOR HOT DIP GALVANNEALED STEEL PLATE - The present invention provides a production facility of hot dip galvannealed steel plate able to produce hot dip galvannealed steel plate on production conditions optimal at all times despite rapid changes in the steel type, plating deposition, and other external factors, wherein the production facility | 08-12-2010 |
20100218857 | HIGH TENSILE STRENGTH GALVANIZED STEEL SHEET EXCELLENT IN FORMABILITY AND METHOD FOR MANUFACTURING THE SAME - A high tensile strength galvanized steel sheet with excellent formability and anti-crush properties contains, in terms of % by mass, 0.05 to 0.3% of C, 0.01 to 2.5% of Si, 0.5 to 3.5% of Mn, 0.003 to 0.100% of P, 0.02% or less of S, 0.010 to 1.5% of Al, 0.007% or less of N, in addition, 0.01 to 0.2% in total of at least one element selected from Ti, Nb, and V, the remainder being Fe and unavoidable impurities, the steel sheet having a microstructure composed of, in terms of area fraction, 20 to 87% of ferrite, 3 to 10% in total of martensite and residual austenite, and 10 to 60% of tempered martensite, and a second phase composed of the martensite, residual austenite, and tempered martensite having an average crystal grain diameter of 3 μm or less. | 09-02-2010 |
20100258216 | METHOD FOR ANNEALING A STRIP OF STEEL HAVING A VARIABLE THICKNESS IN LENGTH DIRECTION - A method for annealing a strip of steel having a variable thickness in its length direction with at least thicker and thinner sections, wherein the strip has been cold rolled to form the thicker and thinner sections, one thicker and one thinner section having a length of at most a few meter. The annealing is performed by continuous annealing. | 10-14-2010 |
20100282374 | GALVANIZED OR GALVANNEALED SILICON STEEL - The invention deals with a hot-dip galvanized or galvannealed steel sheet wherein, the composition of the steel sheet comprises, by weight: 0.01≦C≦0.22%, 0.50≦Mn≦2.0%, 0.2≦Si≦3.0%, 0.005≦Al≦2.0%, Mo<1.0%, Cr≦1.0%, P<0.02%, Ti≦0.20%, V≦0.40%, Ni≦1.0%, Nb≦0.20%, the balance of the composition being iron and unavoidable impurities resulting from the smelting, and the steel sheet comprises a layer of an internal nitride of at least one type of nitride selected from a Si nitride, Mn nitride, Al nitride, complex nitride comprising Si and Mn, or Al and Si, or Al and Mn, or complex nitride comprising Si, Mn and Al, said steel sheet comprising no further outer layer of iron nitride. | 11-11-2010 |
20100314009 | HIGH STRENGTH GALVANIZED STEEL SHEET EXCELLENT IN FORMABILITY AND METHOD FOR MANUFACTURING THE SAME - A high strength galvanized steel sheet having a TS of 780 MPa or more and exhibiting excellent stretch frangeability and bendability and a method for manufacturing the same are provided. The component composition contains C: 0.05% to 0.15%, Si: 0.8% to 2.5%, Mn: 1.5% to 3.0%, P: 0.001% to 0.05%, S: 0.0001% to 0.01%, Al: 0.001% to 0.1%, N: 0.0005% to 0.01%, Cr: 0.1% to 1.0%, Ti: 0.0005% to 0.1%, B: 0.0003% to 0.003%, and the remainder composed of iron and incidental impurities, on a percent by mass basis. The microstructure includes 30% or more of ferrite phase and 30% or more, and 70% or less of martensite phase on an areal fraction basis, wherein regarding the above-described martensite phase, the proportion of a tempered martensite phase is 20% or more relative to the whole martensite phase and the proportion of a martensite phase having a grain diameter of 1 μm or less is 10% or less relative to the whole martensite phase. | 12-16-2010 |
20100326570 | HIGH-STRENGTH QUENCHED FORMED BODY WITH GOOD CORROSION RESISTANCE AND PROCESS FOR PRODUCING THE SAME - A high-strength quenched formed body containing a layer on the surface of an after-quenching formed-body steel material in which layer Zn is a major component and which layer contains 30% by mass or less of Fe, and which layer is present in an amount of 30 g/m | 12-30-2010 |
20110017362 | STEEL FLAT PRODUCT HAVING A METALLIC COATING WHICH PROTECTS AGAINST CORROSION AND METHOD FOR PRODUCING A METALLIC ZN-MG COATING, WHICH PROTECTS AGAINST CORROSION, ON A STEEL FLAT PRODUCT - A steel flat product having a Zn—Mg—Al coating. The coating, which in addition to zinc and unavoidable impurities, comprises in wt. %: Mg: 4-8%, Al: 0.5-1.8% and optionally one or more of the following: Si: <2%, Pb: <0.1%, Ti: <0.2%, Ni: <1%, Cu: <1%, Co: <0.3%, Mn: <0.5%, Cr: <0.2%, Sr: <0.5%, Fe: <3%, B: <0.1%, Bi: <0.1%, Cd: <0.1%, REM<0.2%, and Sn<0.5%. The steel flat product according to the invention is not only outstandingly protected against corrosion, but also welds well and coats well with an organic layer applied subsequently. The invention also relates to a method for producing a steel flat product having a Zn—Mg—Al coating. | 01-27-2011 |
20110024004 | HIGH-STRENGTH STEEL SHEET AND GALVANIZED STEEL SHEET HAVING VERY GOOD BALANCE BETWEEN HOLE EXPANSIBILITY AND DUCTILITY, AND ALSO EXCELLENT IN FATIGUE RESISTANCE, AND METHODS OF PRODUCING THE STEEL SHEETS - The invention is directed to providing, for application in automobiles, construction materials, household appliances and the like, high-strength sheets excellent in formability properties such as hole expansibility and ductility, and also in fatigue resistance, characterized in comprising, in specified contents expressed in mass %, C, Si, Mn, P, S, Al, N and O and a balance of iron and unavoidable impurities, and having a steel sheet structure composed mainly of ferrite and hard structures, a crystal orientation difference between some ferrite adjacent to hard structures and the hard structures of less than 9°, and a maximum tensile strength of 540 MPa or greater. | 02-03-2011 |
20110048586 | DUAL PHASE STEEL SHEET AND METHOD OF MANUFACTURING THE SAME - 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. | 03-03-2011 |
20110083774 | High Strength Steel Sheet and Hot Dip Galvanized Steel Sheet Having High Ductility and Excellent Delayed Fracture Resistance and Method for Manufacturing the Same - A cold rolled steel sheet and a hot dip galvanized steel sheet, which have high strength and elongation, such as a tensile strength of 980 MPa or more and an elongation of 28% or more, and excellent delayed fracture resistance, and manufacturing methods thereof. The cold rolled steel sheet has a composition including 0.05 to 0.3 weight percent C, 0.3 to 1.6 weight percent. Si, 4.0 to 7.0 weight percent Mn, 0.5 to 2.0 weight percent Al, 0.01 to 0.1 weight percent Cr, 0.02 to 0.1 weight percent Ni and 0.005 to 0.03 weight percent Ti, 5 to 30 ppm B, 0.01 to 0.03 weight percent Sb, 0.008 weight percent or less S, balance Fe and impurities. The hot dip galvanized steel sheet has a hot dip galvanized layer or a hot dip galvannealed layer on the cold rolled steel sheet. | 04-14-2011 |
20110139315 | HIGH STRENGTH GALVANIZED STEEL SHEET WITH EXCELLENT FORMABILITY AND METHOD FOR MANUFACTURING THE SAME - A high-strength galvanized steel sheet has a TS of at least 590 MPa and excellent ductility and stretch flangeability and a method for manufacturing the high-strength galvanized steel sheet. The galvanized steel sheet contains, on the basis of mass percent, C: 0.05% to 0.3%, Si: 0.01% to 2.5%, Mn: 0.5% to 3.5%, P: 0.003% to 0.100% or less, S: 0.02% or less, and Al: 0.010% to 1.5%. The total of Si and Al is 0.5% to 2.5%. The remainder are iron and incidental impurities, contain 20% or more of ferrite phase, 10% or less of martensite phase, and 10% to 60% of tempered martensite, on the basis of area percent, and 3% to 10% of retained austenite phase on the basis of volume fraction. The retained austenite has an average grain size of 2.0 μm or less. | 06-16-2011 |
20110139316 | HIGH STRENGTH GALVANNEALED STEEL SHEET WITH EXCELLENT APPEARANCE AND METHOD FOR MANUFACTURING THE SAME - A high strength galvanized steel sheet with excellent appearance that does not have non-uniformity of coating or coating defects or allow linear defects to occur after press forming includes a steel sheet having a ferrite single-phase structure and having a composition containing 0.0005% to 0.0040% by mass of C; 0.1% to 1.0% by mass of Si; 1.0% to 2.5% by mass of Mn; 0.01% to 0.20% by mass of P; 0.015% by mass of less of S; 0.01% to 0.10% by mass of Al; 0.0005% to 0.0070% by mass of N; 0.010% to 0.080% by mass of Ti; 0.0005% to 0.0020% by mass of B; 0.05% to 0.50% by mass of Cu; 0.03% to 0.50% by mass of Ni; and the balance of Fe and incidental impurities. | 06-16-2011 |
20110146852 | HIGH STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A high-strength steel sheet has good ductility and stretch-flangeability and has a tensile strength (TS) of 980 MPa or more. The steel sheet contains 0.17%-0.73% C, 3.0% or less Si, 0.5%-3.0% Mn, 0.1% or less P, 0.07% or less S, 3.0% or less Al, and 0.010% or less N, in which Si+Al is 0.7% or more. | 06-23-2011 |
20110162762 | HIGH STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A high strength steel sheet having composition includes, on a percent by mass basis, C: 0.17% to 0.73%; Si: 3.0% or less; Mn: 0.5% to 3.0%; P: 0.1% or less; S: 0.07% or less; Al: 3.0% or less; and N: 0.010% or less, satisfies Si+Al≧0.7%, and the remainder includes Fe and incidental impurities, with a microstructure that has an area percentage of a total amount of lower bainite and whole martensite 10% to 90% relative to the whole steel sheet microstructure, an amount of retained austenite is 5% to 50%, an area percentage of bainitic ferrite in upper bainite is 5% or more relative to the whole steel sheet microstructure, as-quenched martensite is 75% or less of the total amount of lower bainite and whole martensite, and an area percentage of polygonal ferrite is 10% or less relative to the whole steel sheet microstructure, an average amount of C in retained austenite is 0.70% or more, and tensile strength is 980 MPa or more. | 07-07-2011 |
20110168301 | ULTRAHIGH STRENGTH HOT DIP GALVANIZED STEEL SHEET HAVING MARTENSITIC STRUCTURE AS MATRIX, AND MANUFACTURING METHOD THEREOF - The present invention relates to a hot dip galvanized steel sheet and a manufacturing method thereof. The hot dip galvanize steel sheet includes a steel sheet including a martensitic structure as a matrix, and a hot dip galvanized layer formed on the steel sheet. The steel sheet includes C of 0.05 wt % to 0.30 wt %, Mn of 0.5 wt % to 3.5 wt %, Si of 0.1 wt % to 0.8 wt %, Al of 0.01 wt % to 1.5 wt %, Cr of 0.01 wt % to 1.5 wt %, Mo of 0.01 wt % to 1.5 wt %, Ti of 0.001 wt % to 0.10 wt %, N of 5 ppm to 120 ppm, B of 3 ppm to 80 ppm, an impurity, and the remainder of Fe. | 07-14-2011 |
20110198002 | HIGH-STRENGTH GALVANIZED STEEL SHEET WITH EXCELLENT FORMABILITY AND METHOD FOR MANUFACTURING THE SAME - A high-strength galvanized steel sheet has excellent mechanical properties such as a TS of 1200 MPa or more, an El of 13% or more, and a hole expansion ratio of 50% or more and a method for manufacturing the same. A high-strength galvanized steel sheet excellent in formability contains 0.05% to 0.5% C, 0.01% to 2.5% Si, 0.5% to 3.5% Mn, 0.003% to 0.100% P, 0.02% or less S, and 0.010% to 0.5% Al on a mass basis, the remainder being Fe and unavoidable impurities, and has a microstructure which contains 0% to 10% ferrite, 0% to 10% martensite, and 60% to 95% tempered martensite on an area basis as determined by structure observation and which further contains 5% to 20% retained austenite as determined by X-ray diffractometry. | 08-18-2011 |
20110209800 | HIGH STRENGTH STEEL SHEET WITH GOOD WETTABILITY AND MANUFACTURING METHOD THEREOF - 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. | 09-01-2011 |
20110303328 | HIGH-STRENGTH PRESS HARDENED ARTICLE, AND MANUFACTURING METHOD THEREFOR - A high-strength quenched formed article has a zinc plating layer which is formed at a post-quenching formed steel sheet surface, and which contains 30 g/m | 12-15-2011 |
20110308672 | FURNACE CONFIGURED FOR USE IN BOTH THE GALVANNEALING AND GALVANIZING OF A METAL STRIP - A heat treatment or heat soak furnace for use in both galvannealing and galvanizing processes including a heating apparatus configured to supply heat and remove heat. The heating apparatus may draw hot air from the exhaust of a direct fire strip annealing furnace, gas burners or electric heat exchangers as necessary. The furnace also may include a plurality of cooling mechanisms in order to ensure heat is removed and the temperature within the furnace regulated. In addition, the furnace may include baffles configured to allow portions of the interior of the furnace to be separated into different temperature zones. The furnace under this invention is capable of providing a suitable thermal environment for a desired time, duration, for steel sheet substrates with different chemistries, different coating thicknesses and different process speeds to achieve an optimum phase microstructure of the galvannealed, zinc-iron alloy coating; or to promptly solidify the galvanizing unalloyed zinc coating so that it has a high quality surface morphology. | 12-22-2011 |
20110315279 | HIGH-STRENGTH GALVANIZED STEEL SHEET HAVING EXCELLENT FORMABILITY AND METHOD FOR MANUFACTURING THE SAME - The high-strength galvanized steel sheet having excellent formability has a component composition containing, on the basis of mass percent, 0.05 to 0.2% C, 0.5 to 2.5% Si, 1.5 to 3.0% Mn, 0.001 to 0.05% P, 0.0001 to 0.01% S, 0.001 to 0.1% Al, and 0.0005 to 0.01% N, the balance being Fe and incidental impurities; and the steel sheet has a microstructure including a ferritic phase and a martensitic phase including a tempered-martensitic phase, the ferritic phase having an area fraction of 30% or more relative to an entirety of the microstructure, the martensitic phase having an area fraction of 30 to 50% relative to the entirety of the microstructure, and the tempered-martensitic phase having an area fraction of 70% or more relative to an entirety of the martensitic phase. | 12-29-2011 |
20120018059 | METHOD OF MAKING HOT ROLLED DUAL PHASE STEEL SHEET - A method of making hot rolled steel sheet having a dual phase microstructure with a martensite phase of less than 35% by volume and a ferrite phase of more than 50% by volume and a composition containing by percent weight: 0.01≦C≦0.2; 0.3≦Mn≦3; 0.2≦Si≦2; 0.2≦Cr+Ni≦2; 0.01≦Al≦0.10; Mo less than about 0.2%, 0.0005≦Ca≦0.01, with the balance iron and incidental ingredients. Hot rolled sheet for cold rolling, the silicon range may be from about 0.05% to about 2%, and the amount of molybdenum may be up to 0.5%. Also, the hot rolled steel sheet has a tensile strength of at least 500 megapascals, a hole expansion ratio more than about 50%, and a yield strength/tensile strength ratio less than 70%. | 01-26-2012 |
20120018060 | HIGH-STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - Provided is a method for manufacturing a high-strength galvanized steel sheet, made from a steel sheet containing Si and/or Mn, having excellent exfoliation resistance during heavy machining. When a steel sheet containing 0.01% to 0.18% C, 0.02% to 2.0% Si, 1.0% to 3.0% Mn, 0.001% to 1.0% Al, 0.005% to 0.060% P, and 0.01% or less S on a mass basis, the remainder being Fe and unavoidable impurities, is annealed and galvanized in a continuous galvanizing line, a temperature region with a furnace temperature of A° C. to B° C. (600≦A≦780 and 800≦B≦900) is performed at an atmosphere dew-point temperature of −5° C. or higher in a heating process. | 01-26-2012 |
20120037281 | HIGH STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - The high strength galvanized steel sheet contains C: more than 0.015% and lower than 0.100%, Si: 0.3% or lower, Mn: lower than 1.90%, P: 0.015% or more and 0.05% or lower, S: 0.03% or lower, sol.Al: 0.01% or more and 0.5% or lower, N: 0.005% or lower, Cr: lower than 0.30%, B: 0.0003% or more and 0.005% or lower, and Ti: lower than 0.014% in terms of mass %, and satisfies 2.2≦[Mneq]≦3.1 and 0.42≦8[% P]+150B*≦0.73. The steel microstructure contains ferrite and a second phase, in which the second phase area ratio is 3 to 15%, the ratio of the area ratio of martensite and retained γ to the second phase area ratio is more than 70%, and 50% or more of the area ratio of the second phase exists in the grain boundary triple point. | 02-16-2012 |
20120037282 | HIGH STRENGTH GALVANIZED STEEL SHEET WITH EXCELLENT WORKABILITY AND METHOD FOR MANUFACTURING THE SAME - A high strength galvanized steel sheet with excellent workability, having a component composition containing C: 0.04% or more, and 0.15% or less, Si: 0.7% or more, and 2.3% or less, Mn: 0.8% or more, and 2.2% or less, P: 0.1% or less, S: 0.01% or less, Al: 0.1% or less, N: 0.008% or less, and the remainder composed of iron and incidental impurities on a percent by mass basis, and a microstructure including 70% or more of ferrite phase, 2% or more, and 10% or less of bainite phase, and 0% or more, and 12% or less of pearlite phase on an area fraction basis and 1% or more, and 8% or less of retained austenite phase on a volume fraction basis, wherein an average crystal grain diameter of ferrite is 18 μm or less and an average crystal grain diameter of retained austenite is 2 μm or less. | 02-16-2012 |
20120090737 | HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET AND METHOD FOR PRODUCING SAME - A method for producing a high-strength hot-dip galvanized steel sheet includes a steel sheet containing, in percent by mass, 0.01% to 0.18% of C, 0.02% to 2.0% of Si, 1.0% to 3.0% of Mn, 0.001% to 1.0% of Al, 0.005% to 0.060% of P, 0.01% or less of S, and the balance being Fe and incidental impurities, and a galvanized coating layer on each surface of the steel sheet with a coating weight of 20 to 120 g/m | 04-19-2012 |
20120118438 | HIGH-STRENGTH GALVANNEALED STEEL SHEET HAVING EXCELLENT FORMABILITY AND FATIGUE RESISTANCE AND METHOD FOR MANUFACTURING THE SAME - The present invention provides a high-strength galvanized steel sheet having excellent ductility, stretch flangeability, and fatigue resistance, and a method for manufacturing the same. A high-strength galvannealed steel sheet having excellent formability and fatigue resistance is characterized in that the steel sheet is composed of steel having a composition containing, by % by mass, C: 0.05% to 0.3%, Si: 0.5% to 2.5%, Mn: 1.0% to 3.5%, P: 0.003% to 0.100%, S: 0.02% or less, Al: 0.010% to 0.1%, and the balance including iron and unavoidable impurities, and the steel sheet has a microstructure containing 50% or more of ferrite, 5% to 35% of martensite, and 2% to 15% of pearlite in terms of an area ratio, the martensite having an average gain size of 3 μm or less and an average distance of 5 μm or less between adjacent martensite grains. | 05-17-2012 |
20120118439 | HIGH-STEEL GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A high-strength galvanized steel sheet has a low YP, good stretch flangeability, and excellent corrosion resistance and contains, on a percent by mass basis, more than 0.015% to less than 0.10% of C, 0.5% or less of Si, 1.0% to 1.9% of Mn, 0.015% to 0.050% of P, 0.03% or less of S, 0.01% to 0.5% of sol. Al, 0.005% or less of N, less than 0.40% of Cr, 0.005% or less of B, less than 0.15% of Mo, 0.4% or less of V, and less than 0.020% of Ti, in which 2.2≦[Mneq]≦3.1 and [% Mn]+3.3[% Mo]≦1.9, and [% Mn]+3.3 [% Mo])/(1.3[% Cr]+8[% P]+150B*)<3.5 are satisfied. | 05-17-2012 |
20120125491 | Method for the Hot-Dip Coating of a Flat Steel Product Containing 2 - 35 wt.% of Mn, and a Flat Steel Product - A method by which a flat steel product containing 2-35 wt. % of Mn can be provided with a coating of Zn which adheres well by annealing at an annealing temperature T | 05-24-2012 |
20120152411 | HIGH-STRENGTH GALVANIZED STEEL SHEET AND METHOD OF MANUFACTURING THE SAME - Provided is a galvanized steel sheet having a tensile strength of 770 MPa or more including a steel sheet portion, and a plated layer formed on the surface of the steel sheet portion, in which the plated layer is a galvanized plated layer or an galvannealed plated layer, the steel sheet portion has a soft layer that directly adjoins the interface with the plated layer and an inside layer that is other than the soft layer, the thickness D of soft layer is 0.001% to 5% of thickness t of the steel sheet portion, and, when the hardness of the soft layer measured by nano-indentation method is indicated by H1, and the representative hardness of the steel sheet portion measured by the nano-indentation method is indicated by Ha in cross section that goes along the thickness direction of the steel sheet portion, H1 is 5% to 75% of Ha. | 06-21-2012 |
20120255654 | DUAL PHASE STEEL SHEET AND METHOD OF MANUFACTURING THE SAME - 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. | 10-11-2012 |
20120279617 | HIGH STRENGTH GALVANIZED STEEL SHEET HAVING EXCELLENT FATIGUE RESISTANCE AND STRETCH FLANGEABILITY AND METHOD FOR MANUFACTURING THE SAME - A steel sheet has the chemical composition containing, by mass %, C: 0.04 to 0.13%, Si: 0.9 to 2.3%, Mn: 0.8 to 1.8%, P: 0.1% or less, S: 0.01% or less, Al: 0.1% or less, N: 0.008% or less, the remainder being Fe and the inevitable impurities and a microstructure including, in terms of area ratio, a ferrite phase of 80% or more, a bainitic ferrite phase of 1.0% or more, a pearlite phase of 1.0 to 10.0%, and a martensite phase of 1.0% or more and less than 5.0%, wherein the mean grain size of ferrite is 14 μm or less, the mean grain size of martensite is 4 μm or less, the mean free path of martensite is 3 μm or more, the Vickers hardness of ferrite is 140 or more, and the relationship area ratio of martensite/(area ratio of bainitic ferrite+area ratio of pearlite) 0.6 is satisfied. | 11-08-2012 |
20120305144 | STEEL SHEET AND METHOD OF MANUFACTURING STEEL SHEET - 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. | 12-06-2012 |
20130000796 | HIGH STRENGTH, HOT DIPPED GALVANIZED STEEL SHEET EXCELLENT IN SHAPEABILITY AND METHOD OF PRODUCTION OF SAME - High strength hot dipped galvanized steel sheet with little fluctuation in material quality at the time of production and excellent in shapeability is provided. | 01-03-2013 |
20130008569 | METHOD FOR PRODUCING HIGH-STRENGTH HOT-DIP GALVANNEALED STEEL SHEET - Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion. | 01-10-2013 |
20130008570 | ULTRAHIGH-STRENGTH STEEL SHEET WITH EXCELLENT WORKABILITY, AND MANUFACTURING METHOD THEREOF - Disclosed is an ultra high strength steel plate with at least 1100 MPa of tensile strength that has both an excellent strength-stretch balance and excellent bending workability, and a method for producing the same. The metal structure of the steel plate has martensite, and the soft phases of bainitic ferrite and polygonal ferrite. The area of the aforementioned martensite constitutes 50% or more, the area of the aforementioned bainitic ferrite constitutes 15% or more, and the area of the aforementioned polygonal ferrite constitutes 5% or less (including 0%). When the circle-equivalent diameter of the aforementioned soft phases is measured, the coefficient of variation (standard deviation/mean value) is less or equal to 1.0. The ultra high strength steel plate has at least 1100 MPa of tensile strength. | 01-10-2013 |
20130008571 | METHOD FOR MANUFACTURING THE HIGH STRENGTH STEEL SHEET HAVING EXCELLENT DEEP DRAWABILITY - A high-strength steel sheet has excellent deep drawability with a tensile strength of 390 to 700 MPa and an r-value of 1.1 or more in the orientation in which the r-value is lowest. A steel slab is subjected to finish rolling by hot rolling at a finish rolling delivery temperature of 800° C. or higher, coiling at 550° C. to 720° C., and cooling to form a hot-rolled steel sheet. The hot-rolled steel sheet is pickled and cold-rolled to a rolling reduction of 50% to 85% to form a cold-rolled steel sheet. The cold-rolled steel sheet is annealed at an annealing temperature of 760° C. to 950° C. In this step, a strain of 0.1% to 2.0% is applied in the temperature range of 700° C. to the annealing temperature. | 01-10-2013 |
20130032253 | HIGH-STRENGTH GALVANIZED STEEL SHEET HAVING EXCELLENT FORMABILITY AND METHOD FOR MANUFACTURING THE SAME - A galvanized steel sheet having excellent formability is provided including steel having a composition which contains, on a percent by mass basis, 0.03% to 0.15% of C, less than 0.5% of Si, 1.0% to 2.5% of Mn, 0.05% or less of P, 0.01% or less of S, 0.05% or less of Al, 0.0050% or less of N, 0.05% to 0.8% of Cr, 0.01% to 0.1% of V, and the balance being Fe and inevitable impurities; and a zinc plating film on a surface of a steel sheet, and wherein a microstructure of the steel contains ferrite having an average grain diameter of 15 μm or less and 5% to 40% of martensite in an area ratio, and the ratio of martensite having an aspect ratio of less than 3.0 to all the martensite is more than 95% in area ratio. | 02-07-2013 |
20130087253 | HIGH STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A high strength steel sheet has tensile strength of at least 1470 MPa and (tensile strength×total elongation) of at least 29000 MPa·% with a composition including, by mass %, C: 0.30% to 0.73%, Si: 3.0% or less, Al: 3.0% or less, Si+Al: at least 0.7%, Cr: 0.2% to 8.0%, Mn: 10.0% or less, Cr+Mn: at least 1.0%, P: 0.1% or less, S: 0.07% or less, N: 0.010% or less, and remainder as Fe and incidental impurities; and processing the steel sheet such that microstructure satisfies area ratio of martensite with respect to the microstructure of 15% to 90%; content of retained austenite of 10% to 50%; at least 50% of the martensite is constituted of tempered martensite and area ratio of the tempered martensite with respect to the microstructure is at least 10%; and area ratio of polygonal ferrite with respect to the microstructure is 10% or less. | 04-11-2013 |
20130133786 | METHOD FOR MANUFACTURING HIGH STRENGTH STEEL SHEET - A method for manufacturing a high strength steel sheet includes heating a steel sheet containing at least 0.10 mass % of carbon to either a temperature in an austenite single phase region or a temperature in an (austenite+ferrite) two-phase region; cooling the steel sheet to a cooling stop temperature as a target temperature set within a cooling temperature region ranging from Ms to (Ms−150° C.) to allow a portion of non-transformed austenite to proceed to martensitic transformation; retaining a coldest part in a sheet widthwise direction of the steel sheet at a temperature in a temperature range from the cooling stop temperature as the target temperature to (the cooling stop temperature+15° C.) for 15 seconds to 100 seconds; and heating the sheet to a temperature to temper said martensite, wherein “Ms” represents martensitic transformation start temperature and said cooling temperature region is exclusive of Ms and inclusive of (Ms−150° C.). | 05-30-2013 |
20130153094 | METHOD FOR HOT FORMING A COATED METAL PART AND FORMED PART - A method for manufacturing a coated part having very high mechanical properties using hot forming techniques. The method includes:—providing an annealed steel strip or blank or pre-shaped part that was coated with a metal or metal alloy before the annealing—if a strip is provided, cutting a blank from the strip before or after the annealing—optionally forming a pre-shaped part from the blank—heating the blank or preshaped part to a temperature of 500° C. at an average heating rate of 16° C./s or more—further heating the blank or pre-shaped part to a temperature between 700 and 1000° C.—hot forming the blank or preshaped part into a hot formed part—hardening the hot formed part. A method for manufacturing a coated steel strip, blank or pre-shaped part, and a coated steel strip, blank or part and a hot formed part. | 06-20-2013 |
20130206288 | HIGH-STRENGTH GALVANIZED STEEL SHEET HAVING EXCELLENT FORMABILITY AND CRASHWORTHINESS AND METHOD FOR MANUFACTURING THE SAME - A high-strength galvanized steel sheet having excellent formability and crashworthiness, including a component composition containing 0.03% to 0.13% C, 1.0% to 2.0% Si, 2.4% to 3.5% Mn, 0.001% to 0.05% P, 0.0001% to 0.01% S, 0.001% to 0.1% Al, 0.0005% to 0.01% N, and 0.0003% to 0.01% B on a mass basis, the remainder being Fe and unavoidable impurities, and a microstructure containing a tempered martensitic phase and a bainitic phase such that the sum of an area fraction of the tempered martensitic phase and an area fraction of the bainitic phase is 30% or more (the area fraction of the martensitic phase is 30% or more in the absence of the bainitic phase), wherein a distance of closest approach of the tempered martensitic phase is 10 μm or less and the contents of C, Mn, and B satisfy (1): | 08-15-2013 |
20130269838 | HOT-ROLLED, COLD ROLLED, AND PLATED STEEL SHEET HAVING IMPROVED UNIFORM AND LOCAL DUCTILITY AT A HIGH STRAIN RATE - A multi-phase hot-rolled steel sheet has a metallurgical structure having a main phase of ferrite with an average grain diameter of at most 3.0 μm and a second phase including at least one of martensite, bainite, and austenite. In the surface layer, the average grain diameter of the second phase is at most 2.0 μm, the difference (ΔnH | 10-17-2013 |
20130292010 | HIGH STRENGTH GALVANIZED STEEL SHEET HAVING EXCELLENT DEEP DRAWABILITY AND STRETCH FLANGEABILITY AND METHOD FOR MANUFACTURING THE SAME - A high-strength galvanized steel sheet contains C: 0.010% or more and 0.06% or less, Si: more than 0.5% and 1.5% or less, Mn: 1.0% or more and 3.0% or less, P: 0.005% or more and 0.1% or less, S: 0.01% or less, sol.Al: 0.005% or more and 0.5% or less, N: 0.01% or less, Nb: 0.010% or more and 0.090% or less, and Ti: 0.015% or more and 0.15% or less, on a mass percent basis. The Nb and C contents of the steel satisfy the relation of (Nb/93)/(C/12)<0.20. C* satisfies 0.005≦C*≦0.025. Ferrite constitutes 70% by area ratio or more of the steel sheet. Martensite constitutes 3% by area ratio or more of the steel sheet. C*=C−(12/93)Nb−(12/48){Ti−(48/14)N}, wherein C, Nb, Ti, and N denote the C, Nb, Ti, and N contents of the steel. | 11-07-2013 |
20140102597 | HIGH STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - The high strength galvanized steel sheet contains C: more than 0.015% and lower than 0.100%, Si: 0.3% or lower, Mn: lower than 1.90%, P: 0.015% or more and 0.05% or lower, S: 0.03% or lower, sol.Al: 0.01% or more and 0.5% or lower, N: 0.005% or lower, Cr: lower than 0.30%, B: 0.0003% or more and 0.005% or lower, and Ti: lower than 0.014% in terms of mass %, and satisfies 2.2≦[Mneq]≦3.1 and 0.42≦8[% P]+150B*≦0.73. The steel microstructure contains ferrite and a second phase, in which the second phase area ratio is 3 to 15%, the ratio of the area ratio of martensite and retained γ to the second phase area ratio is more than 70%, and 50% or more of the area ratio of the second phase exists in the grain boundary triple point. | 04-17-2014 |
20140137990 | PROCESS FOR MANUFACTURING FERRITIC HOT ROLLED STEEL STRIP - A process for manufacturing a ferritic hot rolled steel strip is provided. The process includes providing a steel slab, hot rolling the slab to produce a transfer bar and ferritic hot rolling the transfer bar to produce hot rolled strip. The ferritic hot rolled strip is coiled at temperatures between 580-780° C. and has a yield strength between 130-210 MPa, a tensile strength greater than 260 MPa, a uniform elongation greater than 15%, a total elongation to failure greater than 30%, and an n-value greater than 0.2. | 05-22-2014 |
20140158256 | PLANT AND METHOD FOR HOT FORMING BLANKS - There is provided a heating device, in particular an austenitization device, for a plant for hot forming blanks, wherein the heating device is for locally heating, in particular austenitization, regions of the blanks and has at least one burner. Also included is means for moving the burner and/or the flame of the burner to the regions of the blank which are to be subjected to local heating. | 06-12-2014 |
20140209216 | HIGH-MANGANESE STEEL WITH SUPERIOR WELDABILITY AND METHOD FOR MANUFACTURING HOT-DIPPED GALVANIZED STEEL SHEET FROM SAME - The present invention relates to high-manganese steel with superior weldability and to a method for manufacturing hot-dipped galvanized steel sheets from same. The high-manganese steel according to one aspect of the present invention is characterized by comprising, by weight %: C: 0.3-1%; Mn: 8-25%; Al: 1-8%; Si: 0.1-3.0%; Ti: 0.01-0.2%; Sn: 0.06-0.2%; and B: 0.0005-0.01%, with the remainder being Fe and unavoidable impurities. The present invention may provide high-manganese hot-dipped galvanized steel sheets, having high strength and processability and superior surface quality, which can prevent plating failures caused by manganese. | 07-31-2014 |
20140209217 | HIGH-STRENGTH GALVANNEALED STEEL SHEET HAVING EXCELLENT FORMABILITY AND FATIGUE RESISTANCE AND METHOD FOR MANUFACTURING THE SAME - The present invention provides a high-strength galvanized steel sheet having excellent ductility, stretch flangeability, and fatigue resistance, and a method for manufacturing the same. A high-strength galvannealed steel sheet having excellent formability and fatigue resistance is characterized in that the steel sheet is composed of steel having a composition containing, by % by mass, C: 0.05% to 0.3%, Si: 0.5% to 2.5%, Mn: 1.0% to 3.5%, P: 0.003% to 0.100%, S: 0.02% or less, Al: 0.010% to 0.1%, and the balance including iron and unavoidable impurities, and the steel sheet has a microstructure containing 50% or more of ferrite, 5% to 35% of martensite, and 2% to 15% of pearlite in terms of an area ratio, the martensite having an average gain size of 3 μm or less and an average distance of 5 μm or less between adjacent martensite grains. | 07-31-2014 |
20140230971 | HIGH STRENGTH STEEL SHEET HAVING EXCELLENT FORMABILITY AND METHOD FOR MANUFACTURING THE SAME - 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 Ar | 08-21-2014 |
20140338797 | High Strength Steel Exhibiting Good Ductility and Method of Production via In-Line Heat Treatment Downstream of Molten Zinc Bath - Steel with high strength and good formability is produced with compositions and methods for forming austenitic and martensitic microstructure in the steel. Carbon, manganese, molybdenum, nickel copper and chromium may promote the formation of room temperature stable (or meta-stable) austenite by mechanisms such as lowering transformation temperatures for non-martensitic constituents, and/or increasing the hardenability of steel. Thermal cycles utilizing a rapid cooling below a martensite start temperature followed by reheating may promote formation of room temperature stable austenite by permitting diffusion of carbon into austenite from martensite. | 11-20-2014 |
20140338798 | High Strength Steel Exhibiting Good Ductility and Method of Production via Quenching and Partitioning Treatment by Zinc Bath - Steel with high strength and good formability is produced with compositions and methods for forming austenitic and martensitic microstructure in the steel. Carbon, manganese, molybdenum, nickel copper and chromium may promote the formation of room temperature stable (or meta-stable) austenite by mechanisms such as lowering transformation temperatures for non-martensitic constituents, and/or increasing the hardenability of steel. Thermal cycles utilizing a rapid cooling below a martensite start temperature followed by reheating may promote formation of room temperature stable austenite by permitting diffusion of carbon into austenite from martensite. | 11-20-2014 |
20140345753 | SYSTEM AND METHOD FOR HOT-FORMING BLANKS - A system for hot-forming blanks (P) includes at least one heating device ( | 11-27-2014 |
20140360632 | METHOD FOR MANUFACTURING HIGH STRENGTH STEEL SHEET HAVING EXCELLENT FORMABILITY - A method of manufacturing a high strength steel sheet having excellent formability suitable for the material of an automotive part has a tensile strength (TS) of 980 MPa or more and total elongation (EL) is 25% or more. A steel slab has a chemical composition containing C: 0.03% to 0.35%, Si: 0.5% to 3.0%, Mn: 3.5% to 10.0%, P: 0.100% or less, S: 0.02% or less, and the remainder includes Fe and incidental impurities on a percent by mass basis is hot-rolled, a heat treatment is performed, in which an achieved temperature of Ac1 to Ac1+100° C. is held for 3 minutes or more, subsequently, cold rolling is performed at a rolling reduction of 20% or more and, annealing is performed, in which an achieved temperature of Ac1−30° C. to Ac1+100° C. is held for 1 minute or more. | 12-11-2014 |
20150027596 | STEEL SHEET FOR HOT PRESS-FORMING, METHOD FOR MANUFACTURING THE SAME, AND METHOD FOR PRODUCING HOT PRESS-FORMED PARTS USING THE SAME - The invention provides a steel sheet for hot press-forming that can reliably give hot press-formed parts having excellent paint adhesiveness, perforation corrosion resistance and joint corrosion resistance, and also provides a method for manufacturing the steel sheet for hot press-forming, and a method for producing hot press-formed parts using the steel sheet for hot press-forming. The steel sheet for hot press-forming includes a base steel sheet and a Zn-based coating layer with a mass of coating of 10 to 90 g/m | 01-29-2015 |
20150329950 | HIGH-STRENGTH HOT-ROLLED STEEL SHEET HAVING EXCELLENT BAKING HARDENABILITY AND LOW TEMPERATURE TOUGHNESS WITH MAXIMUM TENSILE STRENGTH OF 980 MPA OR MORE - Provided is a high-strength hot-rolled steel sheet consisting of, in mass %, C: 0.01% to 0.2%, Si: 0% to 2.5%, Mn: 0% to 4.0%, Al: 0% to 2.0%, N: 0% to 0.01%, Cu: 0% to 2.0%, Ni: 0% to 2.0%, Mo: 0% to 1.0%, V: 0% to 0.3%, Cr: 0% to 2.0%, Mg: 0% to 0.01%, Ca: 0% to 0.01%, REM: 0% to 0.1%, B: 0% to 0.01%, P: less than or equal to 0.10%, S: less than or equal to 0.03%, O: less than or equal to 0.01%, one or both of Ti and Nb: 0.01% to 0.30% in total, and the balance being Fe and inevitable impurities. The steel sheet has a structure in which a total volume fraction of tempered martensite or lower bainite is 90% or more, a dislocation density thereof is greater than or equal to 5×10 | 11-19-2015 |
20150345002 | Method for Hot-Dip Coating of a Steel Flat Product - The invention specifies a method which allows process-stable hot-dip coating of Ni-alloy steel flat products in a cost- and resource-effective manner, comprising the following steps:
| 12-03-2015 |
20150368730 | METHOD OF TREATMENT OF A RUNNING FERROUS ALLOY SHEET AND TREATMENT LINE FOR ITS IMPLEMENTATION - A method of treatment of a running ferrous alloy sheet containing at least one easily oxidized element is provided. The method includes a step of immersion of the sheet in a molten oxides bath. | 12-24-2015 |
20150368738 | HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - There are provided a high-strength hot-rolled steel sheet having high burring formability and a method for manufacturing the high-strength hot-rolled steel sheet. A high-strength hot-rolled steel sheet having high burring formability contains, on a mass percent basis, C: 0.03% or more and 0.1% or less, Si: less than 0.5%, Mn: more than 0.7% and less than 1.2%, P: 0.05% or less, S: 0.005% or less, N: 0.01% or less, Al: 0.1% or less, and Ti: 0.1% or more and 0.25% or less such that C, S, N, and Ti satisfy Ti*≧0.1 and C×(48/12)−0.1412-24-2015 | |
20150368739 | HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - There are provided a high-strength hot-rolled steel sheet having high burring formability and a method for manufacturing the high-strength hot-rolled steel sheet. The high-strength hot-rolled steel sheet having high burring formability contains, on a mass percent basis, C: 0.013% or more and less than 0.08%, Si: less than 0.5%, Mn: more than 0.8% and less than 1.2%, P: 0.05% or less, S: 0.005% or less, N: 0.01% or less, Al: 0.1% or less, and Ti: 0.03% or more and 0.15% or less such that C, S, N, and Ti satisfy 0.05≦Ti*<0.1 and C×(48/12)−0.1612-24-2015 | |
20150368741 | HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME (AS AMENDED) - There are provided a high-strength hot-rolled steel sheet having high burring formability and a method for manufacturing the high-strength hot-rolled steel sheet. A high-strength hot-rolled steel sheet having high burring formability contains, on a mass percent basis, C: 0.06% or more and 0.13% or less, Si: less than 0.5%, Mn: more than 0.5% and 1.4% or less, P: 0.05% or less, S: 0.005% or less, N: 0.01% or less, Al: 0.1% or less, Ti: 0.05% or more and 0.25% or less, and V: more than 0.15% and 0.4% or less such that S, N, Ti, and V satisfy Ti.+V≧0.35 (wherein Ti.═Ti—N×(48/14)−S×(48/32), and S, N, Ti, and V denote the amounts (% by mass) of the corresponding elements), the remainder being Fe and incidental impurities, wherein the high-strength hot-rolled steel sheet has a microstructure in which a ferrite phase fraction is more than 90%, a carbide containing Ti is precipitated, and 70% or more of the carbide has a grain size of less than 9 nm. | 12-24-2015 |
20160017473 | HIGH STRENGTH GALVANIZED STEEL SHEET HAVING EXCELLENT BENDABILITY AND WELDABILITY, AND METHOD OF MANUFACTURING THE SAME - A method of manufacturing a galvanized steel sheet includes a two-stage temperature raising process which includes: primary heating the sheet from 200° C. to an intermediate temperature of 500 to 800° C. at a primary average heating rate of 5 to 50° C./second at an excess air ratio of 1.10 to 1.20 maintained up to the intermediate temperature; secondary heating the sheet from the intermediate temperature to an annealing temperature of 730 to 900° C. at a secondary average heating rate of 0.1 to 10° C./second at an excess air ratio of less than 1.10 maintained up to the annealing temperature; holding the sheet to the annealing temperature for 10 to 500 seconds; cooling the sheet to 450 to 550° C. at an average cooling rate of 1 to 30° C./second; and subjecting the sheet to a galvanizing process and, optionally, an alloying process. | 01-21-2016 |
20160040275 | High Strength Thin Steel Sheet for the Superior Press Formability and Surface Quality and Galvanized Steel Sheet and Method for Manufacturing the Same - A high strength thin steel sheet that is mainly used for structural members and inner and outer panels for a vehicle, a galvanized steel sheet, and methods of manufacturing the same. The high strength thin steel sheet for superior press formability includes, by weight percent, 0.06 to 0.4% C, 1.0 to 5.0% Mn, 0.05 to 2.5% Si, 0.01 to 2.0% Ni, 0.02 to 2% Cu, 0.01 to 0.04% Ti, 0.05 to 2.5% Al, 0.005 to 0.1% Sb, 0.0005 to 0.004% B, 0.007% or less N, and balance Fe and inevitable impurities, and meeting relation of Ni+0.5×Mn+0.3×Cu>0.9, which is defined as Ni*, and Al/Ni*<1.3 at a same time, and relation of Ti≧0.028×Al. This thin steel sheet is galvanized or galvannealed. | 02-11-2016 |
20160047011 | HIGH-STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME (AS AMENDED) - A high-strength galvanized steel sheet has a chemical composition containing, by mass %, C: 0.16% or more and 0.24% or less, Si: 0.8% or more and 1.8% or less, Mn: 1.0% or more and 3.0% or less, P: 0.020% or less, S: 0.0040% or less, Al: 0.01% or more and 0.1% or less, N: 0.01% or less, Ca: 0.0001% or more and 0.0020% or less, and the balance including Fe and incidental impurities, and a microstructure, in which the total area ratio of a ferrite phase and a bainite phase with respect to the whole microstructure is 30% or more and 70% or less, in which the area ratio of a tempered martensite phase with respect to the whole microstructure is 20% or more and 40% or less, in which the area ratio of a retained austenite phase with respect to the whole microstructure is 10% or more and 20% or less, and in which the area ratio of a martensite phase with respect to the whole microstructure is 2% or more and 20% or less. | 02-18-2016 |
20160145731 | Controlling Liquid Metal Embrittlement In Galvanized Press-Hardened Components - Methods for press hardening galvanized, pre-treated, optionally non-annealed steel alloys are provided. The press-hardened steel alloy may have an ultimate tensile strength (UTS) of at least about 1,000 MPa and is substantially free of liquid metal embrittlement (LME). The press-hardened steel alloy may be further quenched to below room temperature. The press-hardened steel may have a multi-phase microstructure of ferrite at greater than or equal to about 1% to less than or equal to about 60% by volume and a combined volume percentage of martensite, retained austenite, and other transformation products at greater than or equal to about 40% to less than or equal to about 99%. | 05-26-2016 |