JFE STEEL CORPORATION, A CORPORATION OF JAPAN Patent applications |
Patent application number | Title | Published |
20100282376 | ULTRA SOFT HIGH CARBON HOT ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME - An ultra soft high carbon hot-rolled steel sheet has excellent workability. The steel sheet is a high carbon hot-rolled steel sheet containing 0.2 to 0.7% C, and has a structure in which mean grain size of ferrite is 20 μm or larger, the volume percentage of ferrite grains having 10 μm or smaller size is 20% or less, mean diameter of carbide is in a range from 0.10 μm to smaller than 2.0 μm, the percentage of carbide grains having 5 or more of aspect ratio is 15% or less, and the contact ratio of carbide is 20% or less. | 11-11-2010 |
20090277544 | HIGH-TENSILE STRENGTH WELDED STEEL TUBE FOR STRUCTURAL PARTS OF AUTOMOBILES AND METHOD OF PRODUCING THE SAME - A high-tensile strength welded steel tube has excellent formability and torsional fatigue endurance after being formed into cross-sectional shape and then stress-relief annealed. A steel material used has a composition which contains C, Si, Al, 1.01% to 1.99% Mn, 0.041% to 0.150% Ti, 0.017% to 0.150% Nb, P, S, N, and O such that the sum of the content of Ti and that of Nb is 0.08% or more, the content of each of C, Si, and Al being within an appropriate range, the content of each of P, S, N, and O being adjusted to a predetermined value or less. | 11-12-2009 |
20090272469 | STAINLESS-STEEL PIPE FOR OIL WELL AND PROCESS FOR PRODUCING THE SAME - A steel composition contains: 0.05% or less of C; 0.5% or less of Si; 0.20% to 1.80% of Mn; 0.03% or less of P; 0.005% or less of S; 14.0% to 18.0% of Cr; 5.0% to 8.0% of Ni; 1.5% to 3.5% of Mo; 0.5% to 3.5% of Cu; 0.05% or less of Al; 0.20% or less of V; 0.01% to 0.15% of N; and 0.006% or less of O on a mass basis, and satisfies the following expressions: Cr+0.65Ni+0.6Mo+0.55Cu−20C≧18.5 and Cr+Mo+0.3Si−43.5C−0.4Mn−Ni−0.3Cu−9N≦11 (where Cr, Ni, Mo, Cu, C, Si, Mn, and N represent their respective contents (mass %)). After such a steel pipe material is formed into a steel pipe, the steel pipe is quenched by cooling after heating to a temperature of the A | 11-05-2009 |
20090252641 | Hot-Rolled Steel Sheet, Method for Making the Same, and Worked Body of Hot-Rolled Steel Sheet - A steel sheet contains, in terms of percent by mass, C: 0.01 to 0.2%, Si: 2.0% or less, and Mn: 3.0% or less and has a martensite phase as dominant phase and ferrite with a grain size of 20 μm or less as a second phase. The ferrite is contained in area ratio of 1% to 30% and the amount of solute carbon being 0.01 percent by mass of more. The steel sheet can provide a hot-rolled steel sheet suitable for automobile steel sheet, i.e., has excellent press workability and excellent strain aging property whereby the tensile strength significantly increases by heat treatment at about the same temperature as typical baking process after the press-working. Moreover, hardening of the ferrite phase improves the fatigue strength after the strain aging. | 10-08-2009 |
20090214892 | HIGH STRENGTH STEEL SHEET HAVING SUPERIOR DUCTILITY AND METHOD FOR MANUFACTURING THE SAME - A high strength steel sheet and a method for manufacturing the same has superior phosphatability properties and hot-dip galvannealed properties besides a tensile strength of 950 MPa or more and a high ductility, and also having a small variation in mechanical properties with the change in annealing conditions. | 08-27-2009 |
20090202384 | HIGH TENSILE STRENGTH HOT-ROLLED STEEL SHEET HAVING SUPERIOR STRAIN AGING HARDENABILITY AND METHOD FOR PRODUCING THE SAME - A high tensile strength hot-rolled steel sheet having superior strain aging hardenability, which has high formability and stable quality characteristics, and in which satisfactory strength is obtained when the steel sheet is formed into automotive components, thus enabling the reduction in weight of automobile bodies. Specifically, a method for producing a high tensile strength hot-rolled steel sheet having superior strain aging hardenability with a BH of 80 MPa or more, a ΔTS of 40 MPa or more, and a tensile strength of 440 MPa or more includes the steps of heating a steel slab to 1,000° C. or more, the steel slab containing, in percent by mass, 0.15% or less of C, 0.45% or less of Si, 3.0% or less of Mn, 0.08% or less of P, 0.02% or less of S, 0.02% or less of Al, 0.0050% to 0.0250% of N, and optionally 0.1% or less in total of at least one of more than 0.02% to 0.1% of Nb and more than 0.02% to 0.1% of V, the ratio N (mass %)/Al (mass %) being 0.86 or more; rough-rolling the steel slab to form a sheet bar; finish-rolling the sheet bar at a finishing temperature of 800° C. or more; cooling at a cooling rate of 20° C. to 40° C./s or more within 0.5 second after the finish-rolling; and coiling at a temperature of 650° C. to 450° C. or less. | 08-13-2009 |
20090061133 | TWO-PIECE CAN, METHOD FOR MANUFACTURING SAME, AND STEEL SHEET THEREFOR - A two-piece can has sufficient can strength and excellent corrosion resistance and to provide a method for forming the two-piece can easily without generating cracks. The two-piece can uses a laminated steel sheet as the base material and having a can body in a shape of cylinder integrated with bottom. The can body is treated by diametral reduction to become the diameter of opening side thereof smaller than the diameter of can body, and to satisfy the formulae (1) and (2). There is formed a bead at the opening side of the can body, being curled outward from the can at the tip of the opening in a shape of circular arc or vertically long ellipse in cross section, and is further formed a bead having a cross sectional shape of further curled at the tip thereof, an upper bead, and a lower bead: | 03-05-2009 |
20090041608 | IRON-BASED POWDER MIXTURE, AND METHOD OF MANUFACTURING IRON-BASED COMPACTED BODY AND IRON-BASED SINTERED BODY - An iron-based powder mixture for powder metallurgy is provided, in which iron-based powder is blended with at least one selected from talc and steatite, and preferably further blended with metallic soap, thereby when a compacted body is sintered, furnace environment is not adversely affected, and excellent compaction performance is achieved even in a low temperature range of less than 100° C., and more preferably, an obtained sintered body has excellent machining performance. | 02-12-2009 |
20090034203 | Cr-Cu ALLOY, METHOD FOR PRODUCING THE SAME, HEAT-RELEASE PLATE FOR SEMICONDUCTOR, AND HEAT-RELEASE COMPONENT FOR SEMICONDUCTOR - In a Cr—Cu alloy that is formed by powder metallurgy and contains a Cu matrix and flattened Cr phases, the Cr content in the Cr—Cu alloy is more than 30% to 80% or less by mass, and the average aspect ratio of the flattened Cr phases is more than 1.0 and less than 100. The Cr—Cu alloy has a small thermal expansion coefficient in in-plane directions, a high thermal conductivity, and excellent processability. A method for producing the Cr—Cu alloy is also provided. A heat-release plate for semiconductors and a heat-release component for semiconductors, each utilizing the Cr—Cu alloy, are also provided. | 02-05-2009 |
20080264530 | Hot Forged Product With Excellent Fatigue Strength, Method for Making the Same, and Machine Structural Part Made From the Same - A hot forged product including hardened areas introduced by partial cooling after hot forging, and unhardened areas, wherein Vickers hardness V | 10-30-2008 |