Abstract: This ferrite stainless steel includes: by mass %, C: 0.020% or less; N: 0.025% or less; Si: 1.0% or less; Mn: 0.5% or less; P: 0.035% or less; S: 0.01% or less; Cr: 16% to 25%; Al: 0.15% or less; Ti: 0.05% to 0.5%; and Ca: 0.0015% or less, with the balance being Fe and inevitable impurities, wherein the following formula (1) is fulfilled, BI=3Al+Ti+0.5Si+200Ca?0.8??(1) (wherein Al, Ti, Si, and Ca in the formula (1) represent contents (mass %) of the respective components in the steel).
Abstract: This high-strength steel sheet includes: in terms of percent by mass, 0.03 to 0.10% of C; 0.01 to 1.5% of Si; 1.0 to 2.5% of Mn; 0.1% or less of P; 0.02% or less of S; 0.01 to 1.2% of Al; 0.06 to 0.15% of Ti; and 0.01% or less of N; and contains as the balance, iron and inevitable impurities, wherein a tensile strength is in a range of 590 MPa or more, and a ratio between the tensile strength and a yield strength is in a range of 0.80 or more, a microstructure includes bainite at an area ratio of 40% or more and the balance being either one or both of ferrite and martensite, a density of Ti(C,N) precipitates having sizes of 10 nm or smaller is in a range of 1010 precipitates/mm3 or more, and a ratio (Hvs/Hvc) of a hardness (Hvs) at a depth of 20 ?m from a surface to a hardness (Hvc) at a center of a sheet thickness is in a range of 0.85 or more.
Type:
Grant
Filed:
May 26, 2010
Date of Patent:
November 18, 2014
Assignee:
Nippon Steel & Sumitomo Metal Corporation
Abstract: A high strength hot dip galvanized steel strip including, in mass percent, of the following elements: 0.10-0.18% C, 1.90-2.50% Mn, 0.30-0.50% Si, 0.50-0.70% Al, 0.10-0.50% Cr, 0.001-0.10% P, 0.01-0.05% Nb, max 0.004% Ca, max 0.05% S, max 0.007% N, and optionally at least one of the following elements: 0.005-0.50% Ti, 0.005-0.50% V, 0.005-0.50% Mo, 0.005-0.50% Ni, 0.005-0.50% Cu, max 0.005% B, the balance Fe and inevitable impurities, wherein 0.80%<Al+Si<1.05% and Mn+Cr>2.10%. This steel offers improved formability at a high strength, has a good weldability and surface quality together with a good produce-ability and coat-ability.
Abstract: An austenitic stainless steel composition having low nickel and molybdenum and exhibiting high corrosion resistance and good formability. The austenitic stainless steel includes, in weight %, up to 0.20 C, 2.0-6.0 Mn, up to 2.0 Si, 16.0-23.0 Cr, 5.0-7.0 Ni, up to 3.0 Mo, up to 3.0 Cu, 0.1-0.35 N, up to 4.0 W, up to 0.01 B, up to 1.0 Co, iron and impurities. The austenitic stainless steel has a ferrite number less than 11 and an MD30 value less than ?10° C.
Type:
Grant
Filed:
February 26, 2008
Date of Patent:
November 4, 2014
Assignee:
ATI Properties, Inc.
Inventors:
David S. Bergstrom, James M. Rakowski, Charles P. Stinner, John J. Dunn, John F. Grubb
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: The invention relates to an air hardenable high-hardness steel for armoring applications, such as armor plate for use in light armored vehicles and body armor, and having a high level of ballistic performance relative to its plate thickness. In particular, the invention concerns a high ballistic strength martensitic armor steel which, in an air cooled and untempered condition, has a strength coefficient (s0) of higher than 2500 MPa; a flow parameter (P) of higher than 8.0, preferably higher than 18.0; and a manganese content of 1.8 to 3.6% by weight of manganese, preferably 2.8 to 3.1% by weight of manganese. The armor steel also includes retained austenite at a volume fraction of at least 1%, and preferably a volume fraction of 4 to 20%.
Type:
Grant
Filed:
June 15, 2010
Date of Patent:
October 28, 2014
Assignee:
Damascus Armour Development (Pty) Ltd.
Inventors:
Deon Francoise Du Plessis, Jacob Johannes Wessels, Percy Phillip Adams, Roelof Johannes Mostert, Waldo Edmund Stumpf
Abstract: The present invention provides a thick welded steel pipe excellent in low temperature toughness in which contents of Mn and Mo satisfy (Expression 1) below, Pcm obtained by (Expression 2) below is 0.16 to 0.19, and a metal structure of a base material steel plate consists of ferrite being 30 to 95% in an area ratio and a low temperature transformation structure, and in a metal structure of a coarse-grained HAZ, an area ratio of grain boundary ferrite is 1.5% or more, the total area ratio of the grain boundary ferrite and intragranular ferrite is not less than 11% nor more than 90%, an area ratio of MA is 10% or less, and its balance is composed of bainite. 1.2325?(0.85×[Mn]?[Mo])?1.5215??(Expression 1) and Pcm=[C]+[Si]/30+([Mn]+[Cu]+[Cr])/20+[Ni]/60+[Mo]/15+[V]/10??(Expression 2).
Type:
Grant
Filed:
September 13, 2011
Date of Patent:
October 28, 2014
Assignee:
Nippon Steel & Sumitomo Metal Corporation
Abstract: In a method for heat treating a metal tube or pipe for a nuclear power plant, the tube or pipe being accommodated in a batch-type vacuum heat treatment furnace, when the tube or pipe is laid down on and is subjected to heat treatment on a plurality of metal cross beams arranged along a longitudinal direction of the tube or pipe, it is possible to suppress scratches to be formed on the outer surface of the tube or pipe and attributable to heat treatment, and to reduce the discoloration on the outer surface of the tube or pipe by holding the tube or pipe and the metal cross beams in indirect contact with each other by virtue of a heat resistant fabric having a thickness of 0.1 to 1.2 mm interposed in between.
Type:
Grant
Filed:
July 23, 2012
Date of Patent:
October 14, 2014
Assignee:
Nippon Steel & Sumitomo Metal Corporation
Abstract: An austenitic stainless steel having low nickel and molybdenum and exhibiting comparable corrosion resistance and formability properties to higher nickel and molybdenum alloys comprises, in weight %, up to 0.20 C, 2.0-9.0 Mn, up to 2.0 Si, 16.0-23.0 Cr, 1.0-5.0 Ni, up to 3.0 Mo, up to 3.0 Cu, 0.1-0.35 N, up to 4.0 W, up to 0.01 B, up to 1.0 Co, iron and impurities, the steel having a ferrite number of less than 10 and a MD30 value of less than 20° C.
Type:
Grant
Filed:
October 15, 2012
Date of Patent:
October 14, 2014
Assignee:
ATI Properties, Inc.
Inventors:
David S. Bergstrom, James M. Rakowski, Charles P Stinner, John J. Dunn, John F. Grubb
Abstract: This high strength hot-rolled steel sheet includes: in terms of percent by mass, C: 0.05 to 0.12%; Si: 0.8 to 1.2%; Mn: 1.6 to 2.2%; Al: 0.30 to 0.6%; P: 0.05% or less; S: 0.005% or less; and N: 0.01% or less, with the remainder being Fe and unavoidable impurities, wherein a microstructure includes specific ranges (in area %) of ferrite phases as well as martensite phases, and a maximum concentration of Al detected by a glow discharge emission spectroscopic analysis is in a range of 0.75 mass % or less in a region from a surface of the steel sheet to a thickness of 500 nm after being acid-pickled.
Type:
Grant
Filed:
November 16, 2010
Date of Patent:
October 7, 2014
Assignee:
Nippon Steel & Sumitomo Metal Corporation
Abstract: A method of production of high-strength hollow bodies from multiphase martensitic steels includes a heating process, a forming process and a cooling process. A heating device heats hollow steel stock to the austenitic temperature of the material from which the stock is made. The stock is then converted by deformation in a forming device into a hollow body having the final shape. A cooling device thereafter cools the hollow body such that the material with the original austenite microstructure refined by deformation during the forming process cools to a temperature at which incomplete transformation of austenite to martensite occurs. The retained austenite stabilization is performed in an annealing device by diffusion-based carbon partitioning within the material from which the hollow body is made. The hollow body is cooled in a cooling device to ambient temperature after stabilization.
Type:
Grant
Filed:
February 1, 2012
Date of Patent:
October 7, 2014
Assignee:
Zapadoceska Univerzita v Plzni
Inventors:
Bohuslav Ma{hacek over (s)}ek, Hana Jirková, Pavel Hronek, Ctibor {hacek over (S)}tádler, Miroslav Urbánek
Abstract: An austenitic heat-resisting cast steel is disclosed which is composed mainly of Fe and including 0.4˜0.6 wt % of C, 0.5˜1.0 wt % of Si, 2.1˜2.9 wt % of Mn, 2.1˜2.9 wt % of Ni, 18˜22 wt % of Cr, 1.0˜2.0 wt % of Nb, 2.0˜3.0 wt % of W, 0.25˜0.35 wt % of N and other inevitable impurities. More specifically, this austenitic heat-resisting cast steel can beneficially be applied to an exhaust manifold of an automobile to realize a maximum allowable exhaust gas temperature of the exhaust manifold is 950° C.˜1050° C.
Type:
Grant
Filed:
December 12, 2011
Date of Patent:
September 30, 2014
Assignees:
Hyundai Motor Company, Kia Motors Corporation
Abstract: A steel pipe with a wall thickness over 30 mm is subjected to heat treatment of quenching and tempering using a temperature range of at least not less than 750° C. during the heating stage, makes it possible to obtain a heavy-wall seamless steel pipe having excellent toughness by resulting grain refinement. Quenching is by performing water cooling after heating the steel pipe to a temperature in the range of not less than 900° C. to not more than 1000° C. by using, as a heating means, induction heating at a frequency of not more than 200 Hz. Tempering is performed at a temperature in the range of not less than 500° C. to not more than 750° C. Preferably, after the heating by induction heating, a soaking treatment is performed in the temperature range of not less than 900° C. to not more than 1000° C. for 10 minutes or less followed by water cooling.
Type:
Grant
Filed:
January 20, 2012
Date of Patent:
September 30, 2014
Assignee:
Nippon Steel & Sumitomo Metal Corporation
Abstract: A non-oriented electrical steel sheet, containing: C: 0.01 mass % or less; Si: 1.0 mass % or more and 3.5 mass % or less; Al: 0.1 mass % or more and 3.0 mass % or less; Mn: 0.1 mass % or more and 2.0 mass % or less; P: 0.1 mass % or less; S: 0.005 mass % or less; Ti: 0.001 mass % or more and 0.01 mass % or less; N: 0.005 mass % or less; and Y: more than 0.05 mass % and 0.2 mass % or less, with the balance being iron and inevitable impurities.
Type:
Grant
Filed:
February 5, 2013
Date of Patent:
September 23, 2014
Assignee:
Nippon Steel & Sumitomo Metal Corporation
Abstract: Fatigue damage resistant metal or metal alloy wires have a submicron-scale or nanograin microstructure that demonstrates improved fatigue damage resistance properties, and methods for manufacturing such wires. The present method may be used to form a wire having a nanograin microstructure characterized by a mean grain size that is 500 nm or less, in which the wire demonstrates improved fatigue damage resistance. Wire manufactured in accordance with the present process may show improvement in one or more other material properties, such as ultimate strength, unloading plateau strength, permanent set, ductility, and recoverable strain, for example. Wire manufactured in accordance with the present process is suitable for use in a medical device, or other high end application.
Type:
Grant
Filed:
September 18, 2009
Date of Patent:
September 23, 2014
Assignee:
Fort Wayne Metals Research Products Corp
Abstract: Steel for induction hardening wherein coarsening of austenite crystal grains can be prevented even at a high temperature of over 1100° C. such as which occurs at projecting parts of steel parts at the time of induction hardening, the steel for induction hardening characterized by containing, by mass %, C: 0.35 to 0.6%, Si: 0.01 to 1%, Mn: 0.2 to 1.8%, S: 0.001 to 0.15%, Al: 0.001 to 1%, Ti: 0.05 to 0.2%, and Nb: 0.001 to 0.04%, restricting N: 0.0060% or less, P: 0.025% or less, and O: 0.0025% or less, satisfying Nb/Ti?0.015, and having a balance of iron and unavoidable impurities.
Type:
Grant
Filed:
October 7, 2010
Date of Patent:
September 2, 2014
Assignee:
Nippon Steel & Sumitomo Metal Corporation
Abstract: Embodiments of the present disclosure comprise carbon steels and methods of manufacturing thick walled pipes (wall thickness greater than or equal to about 35 mm) there from. In one embodiment, a steel composition is processed that yields an average prior austenite grain size greater than about 15 or 20 ?m and smaller than about 100 ?m. Using this composition, a quenching sequence is provided that yields a microstructure of greater than or equal to about 50% by volume, and less than or equal to about 50% by volume, lower bainite, without substantial ferrite, upper bainite, or granular bainite. After quenching, pipes may be tempered. The quenched and tempered pipes may exhibit yield strengths greater than about 450 MPa (65 ksi) or 485 (70 ksi). Mechanical property measurements find the quenched and tempered pipes suitable for 450 MPa grade and 485 MPa grade, and resistance to sulfide stress corrosion cracking.
Type:
Grant
Filed:
February 6, 2012
Date of Patent:
September 2, 2014
Assignee:
Dalmine S.p.A.
Inventors:
Ettore Anelli, Mariano Armengol, Paolo Novelli, Federico Tintori
Abstract: 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 ?m or less is 10% or less relative to the whole martensite phase.
Abstract: A method fabricating a stainless martensitic steel, including electroslag remelting then cooling an ingot of the steel, then at least one austenitic thermal cycle heating the ingot above its austenitic temperature followed by a cooling. During each cooling: if the cooling is not followed by an austenitic thermal cycle, holding the ingot at a holding temperature included in the ferritic-pearlitic transformation nose for a hold time longer than sufficient for transforming the austenite into a ferritic-pearlitic structure in the ingot as completely as possible at the holding temperature; if the cooling is followed by an austenitic thermal cycle, before its minimum temperature falls below the martensitic transformation start temperature, the ingot is either held throughout the period between the two austenitic thermal cycles at a temperature above the austenitic transformation completion temperature on heating, or held at the holding temperature included in the ferritic-pearlitic transformation nose.
Abstract: A steel sheet undergone precipitation strengthening and refinement in crystal grain size by containing at least one element of 0.005% to 0.05% of Nb, 0.005% to 0.05% of Ti, and 0.0005% to 0.005% of B as a chemical composition is produced through continuous annealing. A steel containing at least one element of Nb, Ti, and B is hot rolled, cooled at a cooling rate of 40° C./s or less, and coiled at 550° C. or higher to facilitate precipitation of cementite after recrystallization annealing. As a result, a steel sheet for a can having a tensile strength of 450 to 550 MPa, a total elongation of 20% or more, and a yield elongation of 5% or less is produced.