Abstract: The present invention relates to a steel for a mold including: on % by mass basis, 0.55%?C?0.70%; 0.30%?Si?0.60%; 0.55%?Mn?1.2%; 5.7%?Cr?6.9%; 1.2%?Mo+W/2?1.6%; 0.55%?V?0.79%; and 0.005%?N?0.1%, with the remainder being Fe and inevitable impurities including, Al?0.020%, Ni?0.20%, S?0.0015%, and Cu?0.10%, and satisfying P1?24 and 4.9?P2?7.3, P1 and P2 being a value obtained based on the following formula (1) and (2), respectively, P1=45?13.6[Si]?7.0([Mo]+[W]/2)?12.9[Ni] (1), P2=7.4[V]+15.8[N]+38.6[Al] (2) in which [M] represents a content of an element M in % by mass basis, and relates to a mold including the steel for a mold.

Abstract: The present invention discloses a Fe—Al-based metal porous membrane and a preparation method thereof, which relate to the technical field of industrial gas-solid and liquid-solid separation and purification, and mainly address problems in the prior art, such as cracking-prone and peeling of a membrane layer of an existing Fe—Al-based metal porous membrane during its preparation and use. The preparation method of the present invention comprises the steps of: adding a Fe—Al-based metal powder and a metal fiber powder into an organic-additive-added water-based solvent, and mixing them into a slurry; casting the slurry, through a casting machine, to form a membrane green body on a metal substrate layer, and letting it dry; and placing the dried membrane green body in a sintering furnace, to remove organic substances and perform high-temperature sintering and predetermined-temperature reaction synthesis.

Abstract: Provided is a steel sheet having: ferrite and pearlite composing 80% or more, in area fraction, of the microstructure; yield strength of 60 ksi or more; elongation of at least 23%; an n-value of at least 0.14; incidental impurities; and, in weight percent: C: 0.03˜0.10 Si: 0˜0.6 Mn: 0.5˜1.5 Cu: 0˜1.0 Ni: 0˜1.0 Nb: 0˜0.06 Ti: 0˜0.1 Mo: 0˜0.5% Cr: 0˜1.0 Al: 0˜0.06 N: 0.0001˜0.006 Ca: 0˜0.006 P: 0˜0.02 S: 0˜0.005.

Abstract: Provided herein is an alloy steel in which carburization is prevented by a processing load, the alloy steel including: about 0.13 to 0.25 wt % of carbon (C), about 0.6 to 1.5 wt % of silicon (Si), about 0.6 to 1.5 wt % of manganese (Mn), about 1.5 to 3.0 wt % of chromium (Cr), about 0.01 to 0.1 wt % of niobium (Nb), about 0.01 to 0.1 wt % of aluminum (Al), about 0.05 to 0.5 wt % of vanadium (V), the balance iron (Fe), and impurities, based on the total weight of the alloy steel.

Abstract: The present invention relates to the application of at least partially bainitic or interstitial martensitic heat treatments on steels, often tool steels or steels that can be used for tools. The first tranche of the heat treatment implying austenitization is applied so that the steel presents a low enough hardness to allow for advantageous shape modification, often trough machining. Thus a steel product is obtained which can be shaped with ease and whose hardness can be raised to a higher working hardness with a simple heat treatment at low temperature (below austenitization temperature).

Abstract: A steel material contains: by mass %, C: greater than 0.05% to 0.18%; Mn: 1% to 3%; Si: greater than 0.5% to 1.8%; Al: 0.01% to 0.5%; N: 0.001% to 0.015%; one or both of V and Ti: 0.01% to 0.3% in total; Cr: 0% to 0.25%; Mo: 0% to 0.35%; a balance: Fe and impurities; and 80% or more of bainite by area %, and 5% or more in total of one or two or more selected from a group consisting of ferrite, martensite and austenite by area %, in which an average block size of the above-described bainite is less than 2.0 ?m, an average grain diameter of all of the above-described ferrite, martensite and austenite is less than 1.0 ?m, an average nanohardness of the above-described bainite is 4.0 GPa to 5.0 GPa, and MX-type carbides each having a circle-equivalent diameter of 10 nm or more exist with an average grain spacing of 300 nm or less therebetween.

Abstract: The steel for hot forming has the following composition in weight %: C: 0.10-0.25, Mn: 1.4-2.8, Si: ?1.0, Cr: ?1.0, Ti: ?0.05, Nb: ?0.05, V: ?0.1, Mo: ?0.1, Al: ?0.05, P: ?0.02, S: ?0.005, Ca: ?0.005, O: ?0.01, N: ?0.02, B: ?0.0004, the remainder being iron and unavoidable impurities. Also disclosed is a strip, sheet or blank produced with such a steel, a method for producing a hot formed product, such a product and the use thereof.

Abstract: A steel material having a chemical composition of, by mass %, C: greater than 0.05% to 0.2%, Mn: 1% to 3%, Si: greater than 0.5% to 1.8%, Al: 0.01% to 0.5%, N: 0.001% to 0.015%, Ti or a sum of V and Ti: greater than 0.1% to 0.25%, Ti: 0.001% or more, Cr: 0% to 0.25%, Mo: 0% to 0.35%, and a balance: Fe and impurities, includes a steel structure being a multi-phase structure having a main phase made of ferrite of 50 area % or more, and a second phase containing one or two or more selected from a group consisting of bainite, martensite and austenite, in which an average nanohardness of the above-described second phase is less than 6.

Abstract: The present invention is a steel for a mechanical structure for cold working, the steel characterized in containing C, Si, Mn, P, S, Al, N, and Cr, the remainder being iron and inevitable impurities; the metal composition having pearlite and pro-eutectoid ferrite; the combined area of the pearlite and pro-eutectoid ferrite being 90% or more of the total composition; the area percentage A of the pro-eutectoid ferrite having the relationship A>Ae, where Ae=(0.8?Ceq)×96.75 (Ceq=[C]+0.1×[Si]+0.06×[Mn]?0.11×[Cr], and “(element names)” indicates the element content (percent in mass); and the mean grain size of the pro-eutectoid ferrite and the ferrite in the pearlite being 15 to 25 ?m.

Abstract: There is provided a metal powder for powder metallurgy including Zr and Si in a manner such that following conditions of (A) and (B) are satisfied, wherein a remainder thereof includes at least one element selected from the group consisting of Fe, Co and Ni, (A) the mass ratio of a content of Zr to a content of Si is 0.03 to 0.3, and (B) the content of Si is 0.35 to 1.5% by mass.

Abstract: A high strength spring steel suppresses ferrite decarburization in a surface layer of a predetermined wire rod manufactured by hot rolling therefrom and possesses excellent decarburization resistance, as compared to conventional high strength spring steel, by optimizing the amount of C, Si, Mn, Cr, Mo and Sb to be added. The spring steel contains, under a certain relationship: 0.35 mass %?C?0.45 mass %; 1.75 mass %?Si?2.40 mass %; 0.1 mass %?Mn?1.0 mass %; 0.01 mass %?Cr<0.50 mass %; 0.01 mass %?Mo?1.00 mass %; P?0.025 mass %; S?0.025 mass %; and O?0.0015 mass %; and at least one selected from 0.035 mass %?Sb?0.12 mass % and 0.035 mass %?Sn?0.20 mass %.

Abstract: A rolled steel bar or wire rod having hot surface fatigue strength, wear resistance, and machinability even after hot forging has a composition containing C, Si, Mn, S, Cr, Mo (optional), Al, and N, with the balance being Fe and impurities. The chemical composition satisfies that fn1 defined by Formula (1) is 1.60 to 2.10. The structure of the rolled steel bar or wire rod for hot forging includes a ferrite-pearlite structure, a ferrite-pearlite-bainite structure, or a ferrite-bainite structure. A maximum value/a minimum value of average ferrite grain size, which is observed and measured randomly in 15 visual fields each having an area of 62500 ?m2 in a cross section, is not more than 2.0. fn1=Cr+2×Mo (1), and each symbol of elements in Formula (1) is substituted by a content (mass %) of a corresponding element.

Abstract: Provided is a high-strength bolt which has a tensile strength of 1,200 MPa or more while exhibiting excellent ductility and delayed facture resistance, and further has an excellent impact toughness which had not been obtained in the conventional high-strength bolt. The high-strength bolt has a tensile strength of 1.2 GPa or more and includes a threaded portion and cylindrical neck portion. The bolt has K of 0.8 or more and satisfies Ho<Hs, where K is defined by the equation: (Ao×Ho)/(As×Hs)=K, in which Ao is an effective cross-sectional area of the cylindrical neck portion with a diameter larger than that of the threaded portion, Ho is a Vickers hardness of a portion at which Ao is measured, As is an effective cross-sectional area of the threaded portion, and Hs is a Vickers hardness of the threaded portion.

Abstract: A rolled steel bar has a composition consisting, by mass percent, of C: 0.27 to 0.37%, Si: 0.30 to 0.75%, Mn: 1.00 to 1.45%, S: 0.008% or more and less than 0.030%, Cr: 0.05 to 0.30%, Al: 0.005 to 0.050%, V: 0.200 to 0.320%, and N: 0.0080 to 0.0200%, the balance being Fe and impurities. The contents of P, Ti and O in the impurities are, by mass percent, P: 0.030% or less, Ti: 0.0040% or less, and O: 0.0020% or less. Y1 expressed by the formula <1> is 1.05 to 1.18. Y1=C+(1/10)Si+(1/5)Mn+(5/22)Cr+1.65V?(5/7)S ??<1>. C, Si, Mn, Cr, V, and S in the formula represent mass percent of the elements. A hot-forged part having a tensile strength of 900 MPa or higher and a transverse endurance ratio of 0.47 can be obtained by the rolled steel bar.

Abstract: The invention relates to a steel alloy for a low alloy steel for producing high-tensile, weldable, hot-rolled seamless steel tubing, in particular construction tubing. The chemical composition (in % by mass) is: 0.15-0.18% C; 0.20-0.40% Si; 1.40-1.60% Mn; max. 0.05% P; max. 0.01% S; >0.50-0.90% Cr; >0.50-0.80% Mo; >0.10-0.15% V; 0.60-1.00% W; 0.0130-0.0220% N; the remainder is made up of iron with production-related impurities; with the optional addition of one or more elements selected from Al, Ni, Nb, Ti, with the proviso that the relationship V/N has a value of between 4 and 12 and the Ni content of the steel is not more than 0.40%.

Abstract: A weld metal according to the present invention has a specific chemical composition, contains carbide particles each having an equivalent circle diameter of greater than 0.5 ?m in a number of 0.25 or less per micrometer of grain boundary length, and has an A-value as specified by Formula (1) of 0.12 or more, Formula (1) expressed as follows: A-value=([V]/51+[Nb]/93)/([Cr]/52+[Mo]/96) ??(1) where [V], [Nb], [Cr], and [Mo] are contents (percent by mass) of V, Nb, Cr, and Mo, respectively, in the weld metal.

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.

Abstract: A cold die steel excellent in the characteristic of suppressing dimensional change, which has a chemical composition in mass %: C: 0.7% or more and less than 1.6%, Si: 0.5 to 3.0%, Mn: 0.1 to 3.0%, P: less than 0.05% including 0%, S: 0.01 to 0.12%, Cr: 7.0 to 13.0%, one or two elements selected from the group consisting of Mo and W: amounts satisfying the formula (Mo+(W/2))=0.5 to 1.7%, V: less than 0.7% including 0, Ni: 0.3 to 1.5%, Cu: 0.1 to 1.0% and Al: 0.1 to 0.7%. Preferably, the die steel satisfies the formula in mass %: Ni/Al=1 to 3.7. It is preferred that the die steel also satisfies the following formula in mass %: (Cr?4.2×C)=5 or less and (Cr?6.3×C)=1.4 or more and that it contains 0.3% or less of Nb.

Abstract: A case hardened gear steel having enhanced core fracture toughness includes by weight percent about 16.3Co, 7.5Ni, 3.5Cr, 1.75Mo, 0.2W, 0.11C, 0.03Ti, and 0.02V and the balance Fe, characterized as a predominantly lath martensitic microstructure essentially free of topologically close-packed (TCP) phases and carburized to include fine M2C carbides to provide a case hardness of at least about 62 HRC and a core toughness of at least about 50 ksi?in.

Abstract: To provide an oil-well steel pipe having excellent SSC resistance. The oil-well steel pipe according to the present invention contains, by mass percent, C: 0.15 to 0.35%, Si: 0.1 to 0.75%, Mn: 0.1 to 1.0%, Cr: 0.1 to 1.7%, Mo: 0.1 to 1.2%, Ti: 0.01 to 0.05%, Nb: 0.010 to 0.030%, Al: 0.01 to 0.1%, P: at most 0.03%, S: at most 0.01%, N: at most 0.007%, and O: at most 0.01%, the balance being Fe and impurities. The Ti content and the Nb content in a residue obtained by bromine-methanol extraction satisfy equation (1): 100×[Nb]/([Ti]+[Nb])?27.5??(1) where the Ti content (mass %) and the Nb content (mass %) in the residue are substituted for [Ti] and [Nb].

Abstract: Disclosed is steel for a leaf spring with high fatigue strength containing, in mass percentage, C: 0.40 to 0.54%, Si: 0.40 to 0.90%, Mn: 0.40 to 1.20%, Cr: 0.70 to 1.50%, Ti: 0.070 to 0.150%, B: 0.0005 to 0.0050%, N: 0.0100% or less, and a remainder composed of Fe and impurity elements. Also disclosed is a high fatigue-strength leaf spring part obtained by forming the steel. The steel for a leaf spring is prepared to have a Ti content and a N content to satisfy a relation of Ti/N?10. Preferably, the leaf spring part is subjected to a shot peening treatment in a temperature range of the room temperature through 400° C. with a bending stress of 650 to 1900 MPa being applied to it.

Abstract: Disclosed is a steel having high manufacturability and better rolling-contact fatigue properties. The steel contains C of 0.65% to 1.30%, Si of 0.05% to 1.00%, Mn of 0.1% to 2.00%, P of greater than 0% to 0.050%, S of greater than 0% to 0.050%, Cr of 0.15% to 2.00%, Al of 0.010% to 0.100%, N of greater than 0% to 0.025%, Ti of greater than 0% to 0.015%, and O of greater than 0% to 0.0025% and further contains iron and unavoidable impurities. Al-containing nitrogen compound particles dispersed in the steel have an average equivalent circle diameter of 25 to 200 nm, and Al-containing nitrogen compound particles each having an equivalent circle diameter of 25 to 200 nm are present in a number density of 1.1 to 6.0 per square micrometer.

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: 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: A tool steel family with outstanding thermal diffusivity, hardness and wear resistance has been developed, also exhibiting good hardenability. Also its mechanical strength, as well as its yield strength, at ambient and high temperature (superior to 600° C.) are high, due to a high alloying level in spite of the high thermal conductivity. Because of its high thermal conductivity and good toughness, steels of this invention have also good resistance to thermal fatigue and thermal shock. This steels are ideal for discontinuous processes where it is interesting to reduce cycle time and that require high hardness and/or wear resistance (plastic injection molding, other plastic forming processes and curing of thermosets, hot forming of sheet . . . ). These tool steels are also appropriate for processes requiring high wear resistance and good resistance to thermal fatigue (forging, hot stamping, light-alloy injection . . . ).

Abstract: The present invention has as its object the provision of steel sheet for hot stamping use which is excellent in part strength after hot stamping and delayed fracture resistance comprised of large C content high strength steel sheet in which effective hydrogen traps are formed in the steel material. The steel sheet of the present invention solves this problem by forming Fe—Mn-based composite oxides in the steel sheet and trapping hydrogen at the interfaces of the composite oxides and matrix steel and in the voids around the composite oxides. Specifically, it provides steel sheet for hot stamping use which is comprised of chemical ingredients which contain, by mass %, C: 0.05 to 0.40%, Si: 0.02% or less, Mn: 0.1 to 3%, S: 0.02% or less, P: 0.03% or less, Al: 0.005% or less, Ti: 0.01% or less, N: 0.01% or less, one or both of Cr and Mo in a total of 0.005 to 1%, and O: 0.003 to 0.03% and which have a balance of Fe and unavoidable impurities and which contains average diameter 0.

Abstract: This weld metal has a predetermined chemical composition, controls the number of oxides in accordance with size, and has an A value stipulated by the belowmentioned formula of no greater than 5.0. A value=(100×[C]?6×[insol.Cr]?2×[insol.Mo]?24×[insol.V]?13×[insol.Nb])×([Mo]?[insol.Mo]), where [insol.Cr], [insol.Mo], [insol.Nb], and [insol.V] are contents (in mass percent) of Cr, Mo, Nb, and V, respectively, present as a compound after stress-relief heat treatment, and [C] and [Mo] are contents (in mass percent) of C and Mo, respectively, contained in the weld metal.

Abstract: Disclosed is a weld metal which is formed by gas-shielded arc welding using a flux-cored wire, and which has a specific chemical composition, in which retained austenite particles are present in a number density of 2500 per square millimeter or more and in a total volume fraction of 4.0% or more based on the total volume of entire structures of the weld metal. The weld metal has excellent hydrogen embrittlement resistance and is resistant to cracking at low temperatures even when the weld metal has a high strength.

Abstract: This weld metal has excellent creep characteristics and has a given chemical composition. In the weld metal, the value A defined by equation (1) is 200 or greater, and carbide particles each having an equivalent-circle diameter of 0.40 ?m or more have an average equivalent-circle diameter less than 0.85 ?m. In the segments that connect the centers of three or more carbide particles which are present on a 6-?m straight line and which each has an equivalent-circle diameter of 0.40 ?m or more, the sum of the lengths of the portions where the segments intersect the carbide particles is 25% or more of the overall length of the segments. Value A=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×104??(1) In the equation, [V], [Nb], [Cr], and [Mo] respectively indicate the contents (mass %) of V, Nb, Cr, and Mo in the weld metal.

Abstract: A work piece for use in abrasive environments with hardbanding is provided. The work piece has at least a protective layer deposited onto at least a portion to be protected. The deposited layer exhibits a hardness of at least 50 Rc, a wear rate of less than 0.5 grams of mass loss as measured according to ASTM G65-04, Procedure A, a wear rate on a contacting secondary body comprising carbon steel of less than 0.005 grams as measured according to modified ASTM G77 wear test. The deposited alloy forms an iron matrix comprising embedded hard particles in an amount of less than 15 vol. %. The embedded hard particles have an average particle size of ranging from 100 nm to 5 ?m. In one embodiment, the deposition is via welding.

Abstract: A rolled steel bar or a wire rod for hot forging capable of coping with both bending/surface fatigue strength of components and machinability at a high level includes: a composition containing, in mass %, C: 0.1 to 0.25%, Si: 0.01 to 0.10%, Mn: 0.4 to 1.0%, S: 0.003 to 0.05%, Cr: 1.60 to 2.00%, Mo: 0.10% or less (including 0%), Al: 0.025 to 0.05%, and N: 0.010 to 0.025%, where a value of fn1 represented in a following formula (1) satisfies 1.82?fn1?2.10: fn1=Cr+2×Mo (1); impurities containing P: 0.025% or less, Ti: 0.003% or less, and O (oxygen): 0.002% or less; and a cross section in which a maximum value/a minimum value of an average ferrite grain diameter is 2.0 or less when measurement by observation is randomly carried out in 15 visual fields with an area per visual field set to be 62500 ?m2.

Abstract: Provided is bearing steel excellent in workability after spheroidizing-annealing and in hydrogen fatigue resistance property after quenching and tempering. The bearing steel has a chemical composition containing, by mass %: 0.85% to 1.10% C; 0.30% to 0.80% Si; 0.90% to 2.00% Mn; 0.025% or less P; 0.02% or less S; 0.05% or less Al; 1.8% to 2.5% Cr; 0.15% to 0.4% Mo; 0.0080% or less N; and 0.0020% or less O, which further contains more than 0.0015% to 0.0050% or less Sb, with the balance being Fe and incidental impurities, to thereby effectively suppress the generation of WEA even in environment where hydrogen penetrates into the steel, so as to improve the roiling contact fatigue life and also the workability such as cuttability and forgeability of the material.

Abstract: Provided is an abrasion-resistant steel plate or sheet which exhibits excellent weld toughness and excellent delayed fracture resistance and is thus suitable for construction machines, industrial machines, and so on. Specifically provided is a steel plate or sheet which contains, in mass %, 0.20 to 0.30% of C, 0.05 to 1.0% of Si, 0.40 to 1.2% of Mn, 0.010% or less of P, 0.005% or less of S, 0.40 to 1.5% of Cr, 0.005 to 0.025% of Nb, 0.005 to 0.03% of Ti, 0.1% or less of Al, 0.01% or less of N, and, as necessary, one or more of Mo, W, B, Cu, Ni, V, REM, Ca and Mg, and has a DI* of 45 to 180 while satisfying the relationship: C+Mn/4?Cr/3+10P?0.47, and which has a microstructure that comprises martensite as the matrix phase. DI*=33.85×(0.1×C)0.5×(0.7×Si+1)×(3.33×Mn+1)×(0.35×Cu+1)×(0.36×Ni+1)×(2.16×Cr+1)×(3×Mo+1)×(1.75×V+1)×(1.

Abstract: A steel for electron-beam welding according to the present invention includes at least C: 0.02% to 0.10%, Si: 0.03% to 0.30%, Mn: 1.5% to 2.5%, Ti: 0.005% to 0.015%, N: 0.0020% to 0.0060%, and O: 0.0010% to 0.0035%, further includes S: limited to 0.010% or less, P: limited to 0.015% or less, and Al: limited to 0.004% or less, with a balance including iron and inevitable impurities. An index value CeEBB obtained by substituting composition of the steel into following Formula 1 falls in the range of 0.42 to 0.65%, the number of oxide having an equivalent circle diameter of 1.0 ?m or more is 20 pieces/mm2 or less at a thickness center portion in cross section along the thickness direction of the steel, and the number of oxide containing Ti of 10% or more and having an equivalent circle diameter of not less than 0.05 ?m or more and less than 0.5 ?m falls in the range of 1×103 to 1×105 pieces/mm2 at the thickness center portion.

Abstract: According to the present invention, there is provided a high strength steel sheet, which has, for example, a tensile strength of 590 to 980 MPa or more, which has favorable workability, and which is useful for an automobile, etc. The high strength steel sheet of the present invention comprises 0.03 to 0.20% C (% by mass in chemical compositions; hereafter, the same holds true), 0.50 to 2.5% Si, 0.50 to 2.5% Mn, and further, preferably 0.02 to 0.2% Mo. Moreover, its metal structure includes ferrite and low temperature transformation phase. The mean grain size of the low temperature transformation phase is 3.0 ?m or less. Further, grains whose size is 3.0 ?m or less occupy 50% or more by area ratio of the low temperature transformation phase, and an average aspect ratio of the low temperature transformation phase is 0.35 or more.

Abstract: In light of the recent analytical technology demanded of fast and accurate measurement of high purity materials, a zirconium crucible is provided for melting an analytical sample and is capable of inhibiting the inclusion of impurities from the crucible by using a high-purity crucible, improving the durability of high-purity zirconium as an expensive crucible material, and increasing the number of times that the zirconium crucible can be used. With this zirconium crucible used for melting an analytical sample in the pretreatment of the analytical sample, the purity excluding gas components is 3N or higher, and the content of carbon as a gas component is 100 mass ppm or less.

Abstract: Provided are: a steel wire rod material for a high-strength spring, which does not undergo the increase in deformation resistance arising from the increase in hardness and can exhibit good wire-drawing processability and the like even when a heat treatment, which deteriorates productivity, is eliminated or a simplified and rapid heat treatment is employed instead; a useful method for producing the steel wire rod material for a high-strength spring; a high-strength spring produced using the steel wire rod material for a high-strength spring as a material; and others. This steel wire rod material for a high-strength spring is a steel wire rod material that has been hot-rolled already, and has a texture having a specified chemical composition and mainly composed of pearlite, wherein the average value (Pave) of the pearlite nodule size numbers and the standard deviation (P?) of the pearlite nodule size numbers fulfill the following formulae (1) and (2), respectively: 9.5?Pave?12.0;??(1) and 0.2?P??0.

Abstract: The invention provides a high-strength pearlitic steel rail, which is inexpensive, and has a tensile strength of 1200 MPa or more, and is excellent in delayed fracture properties. Specifically, the rail contains, in mass percent, C of 0.6 to 1.0%, Si of 0.1 to 1.5%, Mn of 0.4 to 2.0%, P of 0.035% or less, S of 0.0005 to 0.010%, and the remainder is Fe and inevitable impurities, wherein tensile strength is 1200 MPa or more, and size of a long side of an A type inclusion is 250 mm or less in at least a cross-section in a longitudinal direction of a rail head, and the number of A type inclusions, each having a size of a long side of 1 mm to 250 mm, is less than 25 per observed area of 1 mm2 in the cross-section in the longitudinal direction of the rail head.

Abstract: A steel contains, by weight: C: 0.3% to 0.5%, Si: 0.1% to 0.5%, Mn: 1% or less, P: 0.03% or less, S: 0.005% or less, Cr: 0.3% to 1%, Mo: 1% to 2%, W: 0.3% to 1%, V: 0.03% to 0.25%, Nb: 0.01% to 0.15%, Al: 0.01% to 0.1%, the remainder of the chemical composition of the steel being constituted by Fe and impurities or residuals resulting from or necessary to steel production and casting processes. The steel can be used to produce seamless tubes for hydrocarbon wells with a yield strength after heat treatment of 862 MPa or more or even 965 MPa or more.

Abstract: A high strength steel sheet contains, in percent by mass, 0.03 to 0.2% of C, 0.5 to 2.5% of Si, 1 to 3.0% of Mn, 0.01 to 0.5% of Cr, 0.01 to 0.5% of Mo, 0.02 to 0.15% of Al, 0.15% or less of Ti, 0.15% or less of No, and 0.15% or less of V; wherein the remainder includes Fe and inevitable impurities, and the content of Si satisfies the following formula (1), ??4.1?[Si]??2.4??(1), provided, ?=6.9×([C]+[Mn]/6+[Cr]/5+[Mo]/4+[Ti]/15+[Nb]/17+[V]/14)1/2 is given, wherein [ ] shows the quantity (mass percent) of each element contained in the steel sheet. The high strength steel sheet is improved in formability (particularly, elongation), and excellent in balance between strength and elongation.

Abstract: Disclosed is a high-strength steel plate having a predetermined chemical composition, in which a microstructure of the steel plate at a depth of one-fourth to one half the thickness from a surface has an area fraction of bainite of 90% or more, an average lath width of bainite of 3.5 ?m or less, and a maximum equivalent circle diameter of martensite-austenite constituents in bainite of 3.0 ?m or less. The steel plate exhibits high strengths and good drop weight properties and is useful as structural materials for offshore structure, ships, and bridges, as well as materials for pressure vessels in nuclear power plants.

Abstract: A steel rail including a composition of, in mass percent, C of 0.6% to 1.0%, Si of 0.1% to 1.5%, Mn of 0.4% to 2.0%, P of 0.035% or less, S of 0.010% or less, Ca of 0.0010% to 0.010%, and the remainder being Fe and inevitable impurities, wherein the tensile strength is 1200 MPa or more, and the size of a long side of a C type inclusion is 50 ?m or less in at least a cross-section in a longitudinal direction of a rail head, and the number of Ca type inclusions, each having a size of a long side of 1 ?m to 50 ?m, is 0.2 to 10 per observed area of 1 mm2 in the cross-section in the longitudinal direction of the rail head.

Abstract: An ingot steel for bearings has a composition containing C: 0.56% by mass or more and 0.70% by mass or less, Si: 0.15% by mass or more and less than 0.50% by mass, Mn: 0.60% by mass or more and 1.50% by mass or less, Cr: 0.50% by mass or more and 1.10% by mass or less, P: 0.025% by mass or less, S: 0.025% by mass or less, Al: 0.005% by mass or more and 0.500% by mass or less, O: 0.0015% by mass or less, N: 0.0030% by mass or more and 0.015% by mass or less, and a remainder of Fe and incidental impurities, wherein eutectic carbide formation index Ec satisfies 0<Ec?0.25.

Abstract: Drawn heat treated steel wire for high strength spring use is provided containing, by mass %, C: 0.67% to less than 0.9%, Si: 2.0 to 3.5%, Mn: 0.5 to 1.2%, Cr: 1.3 to 2.5%, N: 0.003 to 0.007%, and Al: 0.0005% to 0.003%, having Si and Cr satisfying the following formula: 0.3%?Si?Cr?1.2%, and having a balance of iron and unavoidable impurities, having as impurities, P: 0.025% or less and S: 0.025% or less, furthermore having a circle equivalent diameter of undissolved spherical carbides of less than 0.2 ?m, further having, as a metal structure, at least residual austenite in a volume rate of over 6% to 15%, having a prior austenite grain size number of #10 or more, and having a circle equivalent diameter of undissolved spherical carbides of less than 0.2 ?m.

Abstract: A spring steel contains 0.15-0.40% carbon, 1-3.5% silicon, 0.20-2.0% manganese, 0.05-1.20% chromium, at most 0.030% phosphorus, at most 0.02% sulfur, and at least one of the following: 0.005-0.10% titanium, 0.005-0.05% niobium, and at most 0.25% vanadium. The remainder of said spring steel includes iron and unavoidable impurities. The carbon equivalent (Ceq1) of the provided spring steel, as calculated by formula (1), is at most 0.55. (1) Ceq1=[C]+0.108×[Si]?0.067×[Mn]+0.024×[Cr]?0.05×[Ni]+0.074×[V]. In the formula (1), each symbol in brackets represents the content (mass %) of the corresponding element.

Abstract: The present invention provides a high strength thick steel material excellent in toughness and weldability reduced in amount of C and amount of N, containing suitable amounts of Si, Mn, Nb, Ti, B, and O, having contents of C and Nb satisfying C—Nb/7.74?0.004, having a density of Ti-containing oxides of a particle size of 0.05 to 10 ?m of 30 to 300/mm2, and having a density of Ti-containing oxides of a particle size over 10 ?m of 10/mm2 or less, produced by treating steel by preliminary deoxidation to adjust the dissolved oxygen to 0.005 to 0.015 mass %, then adding Ti and, furthermore, vacuum degassing the steel for 30 minutes or more, smelting it, then continuously casting it to produce a steel slab or billet, heating the steel slab or billet to 1100 to 1350° C., hot rolling the slab or billet to a thickness of 40 to 150 mm, then cooling it.

Abstract: A steel material composition, in particular for producing piston rings and cylinder sleeves, contains the following elements in the cited fractions relative to 100% by weight of the steel material: 0.5-1.2% by weight C, 0-3.0% by weight Cr, 72.0-94.5% by weight Fe, 3.0-15.0% by weight Mn and 2.0-10.0% by weight Si. It can be produced by melting the starting materials and casting the melt into a pre-fabricated mold.

Abstract: The present invention provides a high strength steel sheet with 780 MPa class tensile strength excellent in bending workability and fatigue strength. The high strength steel sheet is (1) a steel sheet whose steel composition contains: C: 0.05-0.20%; Si: 0.6-2.0%; Mn: 1.6-3.0%; P: 0.05% or below; S: 0.01% or below; Al: 0.1% or below; and N: 0.01% or below, the balance comprising iron and inevitable impurities, in which (2) a microstructure comprises a polygonal ferrite structure and a structure formed by low-temperature transformation, in which, when a sheet plane located at a depth of 0.1 mm from a surface of the steel sheet is in the observation under a scanning electron microscope with respect to twenty sights in total in different positions in the sheet-width direction, the maximum value of the areal proportion of the polygonal ferrite (Fmax) and the minimum value of the areal proportion of the ferrite (Fmin) in a 50 ?m×50 ?m area in each sight satisfy Fmax?80%, Fmin?10%, and Fmax?Fmin?40%.

Abstract: “HARD ALLOYS WITH DRY COMPOSITION”, presenting a composition of alloy elements consisting, in mass percentage, of Carbon between 0.5 and 2.0; Chrome between 1.0 and 10.0; Tungsten-equivalent, as given by ratio 2Mo+W, between 7.0 and 14.0; Niobium between 0.5 and 3.5. Niobium can be partially or fully replaced with Vanadium, at a ratio of 2% Niobium to each 1% Vanadium; Vanadium between 0.5 and 3.5. Vanadium can be partially or fully replaced with Niobium, at a ratio of 2% Niobium to each 1% Vanadium; Cobalt lower than 8, the remaining substantially Iron and impurities inevitable to the preparation process. As an option to refine carbides, the steel of the present invention can have content of Nitrogen controlled, below 0.030 and addition of Cerium or other earth elements at content between 0.005 and 0.020. For the same purpose, Silicon and Aluminum can be optionally added, at content between 0.5 and 3.0% for both of them.

Abstract: A weld metal of a high-strength Cr—Mo steel formed by shielded metal arc welding contains: 0.04 to 0.10% by mass C, 0.15 to 0.5% by mass Si, 0.5 to 1.0% by mass Mn, 2.00 to 3.25% by mass Cr, 0.9 to 1.2% by mass Mo, 0.01 to 0.03% by mass Nb, 0.2 to 0.7% by mass V, 0.003% by mass or below and above 0% by mass B, 0.02 to 0.05% by mass O, and the balance of Fe and inevitable impurities. A residual extracted by electrolytic extraction from only an unaffected zone of the weld metal contains precipitated Cr in a Cr content below 0.3% by mass, and precipitated Nb in a Nb content of 0.005% by mass or above.