Abstract: Provided by the present invention are a fine crystallite high-function metal alloy member, a method for manufacturing the same, and a business development method thereof, in which a crystallite of a metal alloy including a high-purity metal alloy whose crystal lattice is a face-centered cubic lattice, a body-centered cubic lattice, or a close-packed hexagonal lattice is made fine with the size in the level of nanometers (10?9 m to 10?6 m) and micrometers (10?6 m to 10?3 m), and the form thereof is adjusted, thereby remedying drawbacks thereof and enhancing various characteristics without losing superior characteristics owned by the alloy.

Abstract: The present invention provides a steel material for automobile chassis parts, having high fatigue characteristics, without a heat treatment, and superior shapeability, and a method of production of such automobile chassis parts. The surface of the steel has a high hardness and the center has a low hardness, providing the superior characteristics. With an annealing step of the invention, it is possible to relieve internal stress and further improve fatigue characteristics.

Abstract: Provided is a low yield ratio, high strength and high toughness steel plate having excellent strain ageing resistance equivalent to API 5L X70 Grade or lower and a method for manufacturing the same. The steel plate has a metallographic microstructure that is a three-phase microstructure including bainite, M-A constituent, and quasi-polygonal ferrite, the area fraction of the bainite being 5% to 70%, the area fraction of the M-A constituent being 3% to 20%, the remainder being the quasi-polygonal ferrite, the equivalent circle diameter of the M-A constituent being 3.0 ?m or less. The steel plate has a yield ratio of 85% or less and a Charpy impact test absorbed energy of 200 J or more at ?30° C. before or after being subjected to strain ageing treatment at a temperature of 250° C. or lower for 30 minutes or less.

Abstract: This high-carbon pearlitic steel rail having excellent ductility, includes: in terms of percent by mass, C: more than 0.85% to 1.40%; Si: 0.10% to 2.00%; Mn: 0.10% to 2.00%; Ti: 0.001% to 0.01%; V: 0.005% to 0.20%; and N: less than 0.0040%, with the balance being Fe and inevitable impurities, wherein contents of Ti and V fulfill the following formula (1), and a rail head portion has a pearlite structure.

Abstract: The present invention relates to a wire rod used in bolts for automobile engines, for example, and more specifically to a wire rod having an improved resistance to hydrogen delayed fracture, to a manufacturing method for same, to a bolt using same and a method for manufacturing the bolt. Provided are a high strength wire rod having a superior resistance to hydrogen delayed fracture and a method for manufacturing same, a high strength bolt using the wire rod and a method for manufacturing same, wherein. the wire rod comprises, 0.3-0.7 wt % C, 0.05-2.0 wt % Si, 0.7-1.5 wt % Mn, 0.01-0.1 wt % Ni, and 30-70 ppm La, and the remainder thereof is comprised by Fe and inevitable impurities.

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: A method of making a hypereutectoid, head-hardened steel rail is provided that includes a step of head hardening a steel rail having a composition containing 0.86-1.00 wt % carbon, 0.40-0.75 wt % manganese, 0.40-1.00 wt % silicon, 0.05-0.15 wt % vanadium, 0.015-0.030 wt % titanium, and sufficient nitrogen to react with the titanium to form titanium nitride. Head hardening is conducted at a cooling rate that, if plotted on a graph with xy-coordinates with the x-axis representing cooling time in seconds, and the y-axis representing temperature in Celsius of the surface of the head of the steel rail, is maintained in a region between an upper cooling rate boundary plot defined by an upper line connecting xy-coordinates (0 s, 775° C.), (20 s, 670° C.), and (110 s, 550° C.) and a lower cooling rate boundary plot defined by a lower line connecting xy-coordinates (0 s, 750° C.), (20 s, 610° C.), and (110 s, 500° C.).

Abstract: When contents of Ti, V, Zr, Nb, and C (mass %) are represented as [Ti], [V], [Zr], [Nb], and [C] respectively, a value of a parameter Q represented by “Q=([Ti]/48+[V]/51+[Zr]/91+[Nb]/93)/([C]/12)” is not less than 0.9 nor more than 1.1. A matrix of a metal structure is a ferrite phase, and the metal structure does not include a non-recrystallized structure. An average grain size of ferrite grains constituting the ferrite phase is not less than 10 ?m nor more than 200 ?m. A precipitate containing at least one selected from the group consisting of Ti, V, Zr, and Nb exists with a density of 10 ?m?3 or more in the ferrite grain. An average grain size of the precipitate is not less than 0.002 ?m nor more than 0.2 ?m.

Abstract: A high-strength hot-rolled steel sheet has a tensile strength (TS) of 540 to 780 MPa, only small variations in strength, and excellent uniformity in strength using a general-purpose Ti-containing steel sheet, which is inexpensive. The high-strength hot-rolled steel sheet includes, on a mass percent basis, 0.05%-0.12% C, 0.5% or less Si, 0.8%-1.8% Mn, 0.030% or less P, 0.01% or less S, 0.005%-0.1% Al, 0.01% or less N, 0.030%-0.080% Ti, and the balance being Fe and incidental impurities. The microstructure have a bainitic ferrite fraction of 70% or more, and the amount of Ti present in a precipitate having a size of less than 20 nm is 50% or more of the value of Ti* calculated using formula (1): Ti*=[Ti]?48/14×[N] (1) where [Ti] and [N] represent a Ti content (percent by mass) and a N content (percent by mass), respectively, of the steel sheet.

Abstract: A powder for a sintered valve sheet made of an iron-based alloy is provided, which has excellent compactibility and abrasion resistance and from which a carbide that may abrade a counterpart is not precipitated. A powder is provided, wherein a molten steel, in which carbon is controlled to be less than 0.1% by mass to avoid precipitation of a carbide, 0.5 to 8.5% by mass of Si, 10 to 25% by mass of Ni, 5 to 20% by mass of Mo, and 5 to 20% by mass of Co are contained, and a remainder includes Fe and incidental impurities, is rapidly cooled by a conventional technique such as a gas atomization method, a water atomization method, or a centrifugal force atomization method, so that a supersaturated solid solution of the alloy elements consisting mainly of austenite, which is effective in softening the powder, is formed. Since the powder has low hardness, the compactibility is excellent at the time of compression molding.

Abstract: A cold-rolled steel sheet satisfies that an average pole density of an orientation group of {100}<011> to {223}<110> is 1.0 to 5.0, a pole density of a crystal orientation {332}<113> is 1.0 to 4.0, a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50, and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50. Moreover, the cold-rolled steel sheet includes, as a metallographic structure, by area %, a ferrite and a bainite of 30% to 99% in total and a martensite of 1% to 70%.

Abstract: There are provided a steel for deep drawing, and a method for manufacturing the steel and a high pressure container. The steel for deep drawing includes, by weight: C: 0.25 to 0.40%, Si: 0.15 to 0.40%, Mn: 0.4 to 1.0%, Al: 0.001 to 0.05%, Cr: 0.8 to 1.2%, Mo: 0.15 to 0.8%, Ni: 1.0% or less, P: 0.015% or less, S: 0.015% or less, Ca: 0.0005 to 0.002%, Ti: 0.005 to 0.025%, B: 0.0005 to 0.0020% and the balance of Fe and inevitable impurities, wherein a microstructure of the steel has a triphase structure of ferrite, bainite and martensite. The steel for deep drawing may be useful to further improve the strength without the deterioration of the toughness by adding a trace of Ti and B, compared to the conventional steels having a strength of approximately 1100 MPa.

Abstract: This high-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability contains, C: 0.01 to 0.4%; Si: 0.001 to 2.5%; Mn: 0.001 to 4.0%; P: 0.001 to 0.15%; S: 0.0005 to 0.03%; Al: 0.001 to 2.0%; N: 0.0005 to 0.01%; and O: 0.0005 to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which at a sheet thickness center portion, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 5.0 or less, and a pole density of the {332}<113> crystal orientation is 4.0 or less, a metal structure contains 5 to 80% of ferrite, 5 to 80% of bainite, and 1% or less of martensite in terms of an area ratio and the total of martensite, pearlite, and retained austenite is 5% or less, and an r value (rC) in a direction perpendicular to a rolling direction is 0.70 or more and an r value (r30) in a direction 30° from the rolling direction is 1.10 or less.

Abstract: Disclosed herein are iron-based alloys having a microstructure comprising a fine-grained ferritic matrix and having a 60+ Rockwell C surface, wherein the ferritic matrix comprises <10 ?m carbide precipitates. Also disclosed are methods of welding comprising forming a crack free hardbanding weld overlay coating with such an iron-based alloy. Also disclosed are families of alloys capable of forming crack-free weld overlays after multiple welding passes.

Abstract: The method provides heat-resistant chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloys having improved creep resistance. A precursor is provided containing preselected constituents of a chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloy, at least one of the constituents for forming a nanoscale precipitate MaXb where M is Cr, Nb, Ti, V, Zr, or Hf, individually and in combination, and X is C, N, O, B, individually and in combination, a=1 to 23 and b=1 to 6. The precursor is annealed at a temperature of 1000-1500° C. for 1-48 h in the presence of a magnetic field of at least 5 Tesla to enhance supersaturation of the MaXb constituents in the annealed precursor. This forms nanoscale MaXb precipitates for improved creep resistance when the alloy is used at service temperatures of 500-1000° C. Alloys having improved creep resistance are also disclosed.

Abstract: A steel product or thin steel cast strip including, by weight, less than 0.25% carbon, between 0.20 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, niobium between 0.01% and 0.20%, and vanadium between 0.01% and 0.20%. The steel product may have a tensile strength of between 550 and 600 MPa after age hardening at a peak temperature of between 700 and 750° C.

Abstract: A precipitation hardening type martensitic stainless steel of an embodiment contains: Cr: 8.5 to 12.5%; Mo: 1 to 2%; Ni: 8.5 to 11.5%; Ti: 0.6 to 1.4%; C: 0.0005 to 0.05%; Al: 0.0005 to 0.25%; Cu: 0.005 to 0.75%; Nb: 0.0005 to 0.3%; Si: 0.005 to 0.75%; Mn: 0.005 to 1%; and N: 0.0001 to 0.03% by mass, and the balance of Fe and unavoidable impurities.

Abstract: An electron-beam welded joint including, by mass %, C: 0.02% to 0.1%, Si: 0.03% to 0.30%, Mn: 1.5% to 2.5%, Ti: 0.005 to 0.015%, N: 0.0020 to 0.0060%, O: 0.0010% to 0.0035%, Nb: 0% to 0.020%, V: 0% to 0.030%, Cr: 0% to 0.50%, Mo: 0% to 0.50%, Cu: 0% to 0.25%, Ni: 0% to 0.50%, B: 0% to 0.0030%, S: limited to 0.010% or less, P: limited to 0.015% or less, Al: limited to 0.004% or less, and a balance consisting of iron and unavoidable impurities, wherein an index value CeEB is 0.49% to 0.60%, a number of oxides having an equivalent circle diameter of 1.0 ?m or more is 20 pieces/mm2 or less, and a number of oxides having an equivalent circle diameter of 0.05 ?m or more and less than 0.5 ?m is 1×103 pieces/mm2 to 1×105 pieces/mm2 at a thickness center portion.

Abstract: The present invention provides a maraging steel containing: 0.10?C?0.30 mass %, 6.0?Ni?9.4 mass %, 11.0?Co?20.0 mass %, 1.0?Mo?6.0 mass %, 2.0?Cr?6.0 mass %, 0.5?Al?1.3 mass %, and Ti?0.1 mass %, with the balance being Fe and unavoidable impurities, and satisfying 1.00?A?1.08, in which A is 0.95+0.35×[C]?0.0092×[Ni]+0.011×[Co]?0.02×[Cr]?0.001×[Mo], where [C] indicates a content (mass %) of C, [Ni] indicates a content (mass %) of Ni, [Co] indicates a content (mass %) of Co, [Cr] indicates a content (mass%) of Cr, and [Mo] indicates a content (mass%) of Mo, respectively, The maraging steel has a tensile strength of 2,300 MPa or more and is also excellent in the toughness/ductility and fatigue characteristics.

Abstract: A value of a parameter Q represented by “Q=([Ti]/48+[V]/51+[Zr]/91+[Nb]/93)/([C]/12)” is not less than 0.9 nor more than 1.1, when contents of Ti, V, Zr, Nb, and C (mass %) are represented as [Ti], [V], [Zr], [Nb], and [C] respectively. A matrix of a metal structure is a ferrite phase, and the metal structure does not contain a non-recrystallized structure. An average grain size of ferrite grains constituting the ferrite phase is not less than 30 ?m nor more than 200 ?m. A precipitate containing at least one selected from the group consisting of Ti, V, Zr, and Nb exists with a density of 1 particle/?m3 or more in the ferrite grain. An average grain size of the precipitate is not less than 0.002 ?m nor more than 0.2 ?m.

Abstract: Disclosed are quaternary ammonium salts containing non-halogen anions such as carbonates, bicarbonates, phosphates, glycolates and mixtures thereof as conversion coatings or additives imparting anti-corrosive properties to paints. The invention relates to a method for inhibiting the corrosion of metal surfaces by applying a composition containing one or more quaternary ammonium carbonate or bicarbonate. The disclosure is also directed to anti-corrosive coatings for metal substrates containing these compounds and to metal substrates having these anticorrosive coatings.

Abstract: A multi-phase steel including in % wt. C: 0.14-0.25%, Mn: 1.7-2.5%, Si: 0.2-0.7%, Al: 0.5-1.5%, Cr: <0.1%, Mo: <0.05%, Nb: 0.02-0.06%, S: up to 0.01%, P: up to 0.02%, N: up to 0.01% and optionally at least one of Ti, B, and V according to the following stipulation: Ti: up to 0.1%, B: up to 0.002%, V: up to 0.15%, with the remainder iron and unavoidable impurities, wherein the microstructure has at least 10% vol. ferrite and at least 6% vol. residual austenite and the steel has a tensile strength Rm of at least 950 MPa, a yield point ReL of at least 500 MPa and an elongation at break A80 measured in the transverse direction of at least 15%. A method of producing the multi-phase steel.

Abstract: Disclosed herein are iron-based alloys having a microstructure comprising a fine-grained ferritic matrix and having a 60+ Rockwell C surface, wherein the ferritic matrix comprises <10 ?m Nb and W carbide precipitates. Also disclosed are methods of welding comprising forming a crack free hardbanding weld overlay coating with such an iron-based alloy. Also disclosed are methods of designing an alloy capable of forming a crack free hardbanding weld overlay, the methods comprising the steps of determining an amorphous forming epicenter composition, determining a variant composition having a predetermined change in constituent elements from the amorphous forming epicenter composition, and forming and analyzing an alloy having the variant composition.

Abstract: Disclosed herein are iron-based alloys having a structure comprising fine-grained ferritic matrix and having a 60+ Rockwell C surface, wherein the ferritic matrix comprises <10 ?m Nb and W carbide precipitates. Also disclosed are methods of welding comprising forming a crack free hardbanding weld overlay coating with such an iron-based alloy. Also disclosed are methods of designing an alloy capable of forming a crack free hardbanding weld overlay, the methods comprising the step determining an amorphous forming epicenter composition, determining a variant composition having a predetermined change in constituent elements from the amorphous forming epicenter composition, and forming and analyzing an alloy having the variant composition.

Abstract: Steel is described having a chemical composition, in weight-%, of 0.3 to 0.5% carbon (C), from traces to a max. of 1.5% silicon (Si), 0.2 to 1.5% manganese (Mn), 0.01 to 0.2% sulfur (S), 1.5 to 4% chromium (Cr), 1.5 to 5% nickel (Ni), 0.5 to 2% molybdenum (Mo), which at least partially may be replaced by twice as much tungsten (W), 0.2 to 1.5% vanadium (V), from traces to a max. of 0.2% rare earth metals, and a balance essentially of only iron, impurities and accessory elements in normal amounts. In addition, a method for manufacturing a blank of the steel and a process for manufacturing a cutting tool body or holder for cutting tools of the steel is described.

Abstract: The invention provides a steel material with satisfactory hydrogen embrittlement resistance, and particularly it relates to high-strength steel with satisfactory hydrogen embrittlement resistance and a strength of 1200 MPa or greater, as well as a process for production thereof. At least one simple or compound deposit of oxides, carbides or nitrides as hydrogen trap sites which trap hydrogen with a specific trap energy is added to steel, where the mean sizes, number densities, and length-to-thickness ratios (aspect ratio) are in specific ranges. By applying the specific steel components and production process it is possible to obtain high-strength steel with excellent hydrogen embrittlement resistance.

Abstract: A steel sheet for bottom covers of aerosol cans includes, as chemical composition, C: 0.025 to 0.065mass %, Mn: 0.10 to 0.28mass %, P: 0.005 to 0.03mass %, Al: 0.01 to 0.04mass %, N: 0.0075 to 0.013mass %, Si: limited to 0.05mass % or less, S: limited to 0.009mass % or less, and balance consisting of Fe and unavoidable impurities, wherein yield point YP in rolling direction after aging treatment is in range of 460 to 540 MPa, total elongation in the rolling direction after the aging treatment is 15% or more, yield point elongation ELYP in the rolling direction after the aging treatment is 6% or less, and sheet thickness t in unit of mm, the yield point YP in unit of MPa in the rolling direction after the aging treatment, and the yield point elongation ELYP in unit of % in the rolling direction after the aging treatment satisfy 130?t×YP×(1?ELYP/100).

Abstract: A multi-phase steel which in addition to iron and unavoidable impurities includes (in % wt.) C: 0.14-0.25%, Mn: 1.7-2.5%, Si: 1.4-2.0%, Al: <0.1%, Cr: <0.1%, Mo: <0.05%, Nb: 0.02-0.06%, S: up to 0.01%, P: up to 0.02%, N: up to 0.01% and optionally one of Ti, B, and V according to the following stipulation: Ti: ?0.1%, B: ?0.002%, V: ?0.15%. A cast semi-finished product, is hot rolled starting at an initial temperature of 1100-1300° C. and ending at a final temperature of 820-950° C., coiled at 400-750° C., cold rolled into the cold flat product at degrees of 30-80%, and subjected to a heat treatment including continuous annealing at 20° C.+Ac1-Ac3 and overageing at 350-500° C.

Abstract: A steel sheet contains, on a mass percent basis, 0.03%-0.12% C, 0.5% or less Si, 0.8%-1.8% Mn, 0.030% or less P, 0.01% or less S, 0.005%-0.1% Al, 0.01% or less N, 0.035%-0.100% Ti, and the balance being Fe and incidental impurities and has microstructures with a fraction of polygonal ferrite of 80% or more, the polygonal ferrite having an average grain size of 5 to 10 ?m. The amount of Ti present in a precipitate having a size of less than 20 nm is 70% or more of the value of Ti* calculated using expression (1): Ti*=[Ti]?48×[N]/14??(1) where [Ti] and [N] represent a Ti content (percent by mass) and a N content percent by mass), respectively, of the steel sheet.

Abstract: The present invention provides a steel material for hardening, including chemical components, by mass %, of: C: 0.15 to 0.60%; Si: 0.01 to 1.5%; Mn: 0.05 to 2.5%; P: 0.005 to 0.20%; S: 0.001 to 0.35%; Al: over 0.06 to 0.3%; and total N: 0.006 to 0.03%, with a balance including Fe and inevitable impurities including B of not more than 0.0004%, in which a hardness R at a position 5 mm away from a quenching end measured through a Jominy-type end-quenching method specified in JIS G 0561, and a calculation hardness H at a position 4.763 mm away from the quenching end satisfy the following Equation (1). H×0.948?R?H×1.

Abstract: A seamless expandable oil country tubular article, which has a superior pipe expansion property in a expanding process at an expand ratio of more than about 30% although having a high strength such as a tensile strength (TS) of about 600 MPa or more, and a manufacturing method thereof, the seamless expandable oil country tubular goods being in an as-rolled state or being processed, optionally necessary, by inexpensive nonthermal-refining type heat treatment.

Abstract: Embodiments of the present disclosure comprise carbon steels and methods of manufacture. In one embodiment, a double austenizing procedure is disclosed in which a selected steel composition is formed and subjected to heat treatment to refine the steel microstructure. In one embodiment, the heat treatment may comprise austenizing and quenching the formed steel composition a selected number of times (e.g., 2) prior to tempering. In another embodiment, the heat treatment may comprise subjecting the formed steel composition to austenizing, quenching, and tempering a selected number of times (e.g., 2). Steel products formed from embodiments of the steel composition in this manner (e.g., seamless tubular bars and pipes) will possess high yield strength, at least about 175 ksi (about 1200 MPa) while maintaining good toughness.

Abstract: The present invention provides a steel part for machine structural use whose fatigue strength and toughness are improved and a manufacturing method thereof. A steel part made of a steel containing, in mass %, C: 0.05 to 0.20%, Si: 0.10 to 1.00%, Mn: 0.75 to 3.00%, P: 0.001 to 0.050%, S: 0.001 to 0.200%, V: exceeding 0.20 to 0.25%, Cr: 0.01 to 1.00%, Al: 0.001 to 0.500%, and N: 0.0080 to 0.0200%, and a balance being composed of Fe and inevitable impurities, in which a steel structure contains a bainite structure having an area ratio of 95% or more, a bainite lath width is 5 ?m or less, V carbide having an average grain diameter of not less than 4 nm nor more than 7 nm dispersedly exists in the bainite structure, and an area ratio of V carbide in the bainite structure is 0.18% or more.

Abstract: Described are a high tensile strength galvanized steel sheet with high strength and excellent formability (elongation and stretch-flange ability), and manufacturing method. Tensile strength ?980 MPa and excellent formability, having (i) defined composition ranges for C, Si, Mn, P, S, N, Al, Ti, V, Solute V, Solute Ti, and Fe and incidental impurities, (ii) microstructure with fine carbides dispersion precipitated therein, the fine carbides containing Ti and V and having the average particle diameter <10 nm, and volume ratio with respect to the entire microstructure ?0.007, and (iii) matrix as ferrite phase having area ratio with respect to the entire microstructure ?97%; and hot-dip galvanized/galvannealed coating on a surface of the hot rolled steel sheet. Contents of C, Ti, V, S, N satisfy (1) Ti?0.10+N/14*48+S/32*48) and (2) 0.8?(Ti/48+V/51)/(C/12)?1.2.

Abstract: The present invention provides a steel part for machine structural use whose fatigue strength and toughness are improved and a manufacturing method thereof. A steel part made of a steel containing, in mass %, C: 0.05 to 0.20%, Si: 0.10 to 1.00%, Mn: 0.75 to 3.00%, P: 0.001 to 0.050%, S: 0.001 to 0.200%, V: 0.05 to 0.20%, Cr: 0.01 to 1.00%, Al: 0.001 to 0.500%, and N: 0.0080 to 0.0200%, and a balance being composed of Fe and inevitable impurities, in which a steel structure contains a bainite structure having an area ratio of 95% or more, a bainite lath width is 5 ?m or less, V carbide having an average grain diameter of not less than 4 nm nor more than 7 nm dispersedly exists in the bainite structure, and an area ratio of V carbide in the bainite structure is 0.18% or more.

Abstract: A hot-rolled steel bar or wire rod consisting of C: 0.1 to 0.3%, Si: 0.05 to 1.5%, Mn: 0.4 to 2.0%, S: 0.003 to 0.05%, Cr: 0.5 to 3.0%, Al: 0.02 to 0.05%, and N: 0.010 to 0.025%, the balance being Fe and impurities, and the impurities containing P: 0.025% or less, Ti: 0.003% or less, and O: 0.002% or less, wherein the structure thereof is composed of a ferrite-pearlite structure, ferrite-pearlite-bainite structure, or ferrite-bainite structure; the standard deviation of ferrite fractions at the time when randomly selected 15 viewing fields of a transverse cross section are observed and measured with the area per one viewing field being 62,500 ?m2 is 0.10 or less; and in a region from the surface to one-fifth of the radius and a region from the center to one-fifth of the radius in the transverse cross section, the amount of Al precipitating as AlN is 0.005% or less, and the density in terms of the number of AlN having a diameter of 100 nm or larger is 5/100 ?m2 or less.

Abstract: A piston ring material is provided which retains excellent mechanical properties and processability, which are required of piston ring materials, and has wearing resistance and scuffing resistance, which are sliding properties required of piston rings. The piston ring material, which is for use in internal combustion engines, contains, in terms of mass %, 0.3-0.8% carbon, 0.1-3.0% silicon, 0.1-3.0% manganese, 0.01-0.3% sulfur, 0.1-2.0% chromium, and 0.05-2.0% the sum of titanium and/or zirconium, with the remainder being iron and incidental impurities. The titanium and/or zirconium contained in the piston ring material and the sulfur contained therein satisfy the following relationship. [Ti (%)+½Zr (%)]/S (%)?5.0 Preferably, the material may contain one or more members selected from up to 1.0% copper, less than 3.0% molybdenum, up to 1.0% aluminum, and less than 2.0% nickel, in terms of mass %.

Abstract: The present invention provides a steel part for machine structural use whose fatigue strength and toughness are improved and a manufacturing method thereof. A steel part made of a steel containing, in mass %, C: 0.05 to 0.20%, Si: 0.10 to 1.00%, Mn: 0.75 to 3.00%, P: 0.001 to 0.050%, S: 0.001 to 0.200%, V: exceeding 0.25 to 0.50%, Cr: 0.01 to 1.00%, Al: 0.001 to 0.500%, and N: 0.0080 to 0.0200%, and a balance being composed of Fe and inevitable impurities, in which a steel structure contains a bainite structure having an area ratio of 95% or more, a bainite lath width is 5 ?m or less, V carbide having an average grain diameter of not less than 4 nm nor more than 7 nm dispersedly exists in the bainite structure, and an area ratio of V carbide in the bainite structure is 0.18% or more.

Abstract: A method for producing a tempered martensitic heat resistant steel for high temperature applications at an application temperature of up to 650° C. and to a steel produced by the method. The use of the steel in the production of components for high temperature applications such as turbine blades or casings, bolting and boiler tubes, heat exchangers or other elements in power generation systems.

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: The present disclosure is directed and formulations and methods to provide non-stainless steel alloys having relative high strength and ductility. The alloys may be provided in sheet or pressed form and characterized by their particular alloy chemistries and identifiable crystalline grain size morphology. The alloys are such that they include boride pinning phases. In what is termed a Class 1 Steel the alloys indicate tensile strengths of 630 MPa to 1100 MPa and elongations of 10-40%. Class 2 Steel indicates tensile strengths of 875 MPa to 1590 MPa and elongations of 5-30%. Class 3 Steel indicates tensile strengths of 1000 MPa to 1750 MPa and elongations of 0.5-15%.

Abstract: Disclosed herein is a precipitation hardening cold-rolled steel sheet and method for manufacturing the same, which can be used for structural components such as seat rails and the like of a vehicle body. The steel sheet comprises, by weight %, C: 0.07˜0.1%, Mn: 1.4˜1.7%, P: 0.05˜0.07%, S: 0.005% or less, acid-soluble Al: 0.1˜0.15%, Nb: 0.06˜0.09%, B: 0.0008˜0.0012%, Sb: 0.02˜0.06%, and the balance of Fe and other unavoidable impurities. The steel sheet has a yield strength of 750 MPa or more and a yield ratio of 85% or more, and is free from surface defects due to a very low degree of oxide enrichment on the surface thereof.

Abstract: A high-strength steel sheet according to the present invention not only is suitably adjusted in its chemical elements composition, but also has a DE value defined by the following Equation (1) of 0.0340% or more, and a carbon equivalent Ceq defined by the following Equation (2) of 0.45% or less: DE value=[Ti]+[Nb]+0.3[V]+0.0075[Cr]??(1) where, [Ti], [Nb], [V], and [Cr] represent contents (mass %) of Ti, Nb, V, and Cr, respectively; Ceq=[C]+[Mn]/6+([Cr]+[Mo]+[V])/5+([Cu]+[Ni])/15 ??(2) where, [C], [Mn], [Cr], [Mo], [V], [Cu], and [Ni] represent contents (mass %) of C, Mn, Cr, Mo, V, Cu, and Ni, respectively. A high-strength steel sheet resistant to strength reduction and good in low-temperature toughness of HAZ even when subjected for a long time to a stress-relief annealing process after being processed by welding, is provided.

Abstract: On a cross section with a sheet width direction of a high-strength hot-rolled steel sheet set as a normal line, with regard to an inclusion having a major diameter of 3.0 ?m or more, a maximum of a major diameter/minor diameter ratio expressed by (a major diameter of the inclusion)/(a minor diameter of the inclusion) is 8.0 or less, and a sum total of a rolling direction length per 1 mm2 cross section of a predetermined inclusion group composed of plural inclusions each having a major diameter of 3.0 ?m or more and a predetermined extended inclusion having a length in a rolling direction of 30 ?m or more is 0.25 mm or less. The plural inclusions composing the predetermined inclusion group congregate in both the rolling direction and a direction perpendicular to the rolling direction 50 ?m or less apart from each other. The predetermined extended inclusion is spaced over 50 ?m apart from all the inclusions each having a major diameter of 3.

Abstract: The invention proposes a lever-type cam follower (1) made without chip removal out of a sheet steel for use in a valve train of an internal combustion engine for actuating at least one gas exchange valve. This lever-type cam follower (1) is characterized by being made of a cold-forming, core-hardening heat-treatable steel.

Abstract: Embodiments of the present application are directed towards steel compositions that provide improved properties under corrosive environments. Embodiments also relate to protection on the surface of the steel, reducing the permeation of hydrogen. Good process control, in terms of heat treatment working window and resistance to surface oxidation at rolling temperature, are further provided.

Abstract: Disclosed is a ball for a constant velocity joint, and a method for producing the same. The ball for a constant velocity joint is produced via a quenching step for heating a spherical body consisting of a material corresponding to a high carbon chromium bearing steel regulated by Japanese Industrial Standards (JIS) to 840-900° C. and then cooling the spherical body under such a condition as 10-25 vol. % of austenite remains up to a first part where the depth from the surface is 0.1 mm, a step for tempering the spherical body at 150° C. or more, and a step for shot peening the spherical body and imparting a compression residual stress of ?1000 MPa or more to a region reaching second part where the depth from the surface is 0.2 mm.

Abstract: A transformation toughened, high-strength steel alloy useful in plate steel applications achieves extreme fracture toughness (Cv > 80 ft-lbs corresponding to KId=200 ksi.in ½) at strength levels of 150-180 ksi yield strength, is weldable and formable. The alloy is characterized by dispersed austenite stabilization for transformation toughening to a weldable, bainitic plate steel and is strengthened by precipitation of M2C carbides in combination with copper and nickel. The desired microstructure is a matrix containing a bainite-martensite mix, BCC copper and M2C carbide particles for strengthening with a fine dispersion of optimum stability austenite for transformation toughening. The bainite-martensite mix is formed by air-cooling from solution treatment temperature and subsequent aging at secondary hardening temperatures to precipitate the toughening and strengthening dispersions.

Abstract: Provided is a low yield ratio, high strength and high uniform elongation steel plate having excellent strain ageing resistance equivalent to API 5L X70 Grade or lower and a method for manufacturing the same. In particular, the steel plate contains 0.06% to 0.12% C, 0.01% to 1.0% Si, 1.2% to 3.0% Mn, 0.015% or less P, 0.005% or less S, 0.08% or less Al, 0.005% to 0.07% Nb, 0.005% to 0.025% Ti, 0.010% or less N, and 0.005% or less O on a mass basis, the remainder being Fe and unavoidable impurities. The low yield ratio, high strength and high uniform elongation steel plate has a metallographic microstructure that is a two-phase microstructure consisting of bainite and M-A constituent, the area fraction of the M-A constituent being 3% to 20%, the equivalent circle diameter of the M-A constituent being 3.0 ?m or less.