Abstract: In accordance with one aspect of the present disclosure, there is provided a steel material for a tailor-welded blank, including 0.04 to 0.06 wt % of carbon (C), 1.2 to 1.5 wt % of manganese (Mn), 0.01 to 0.10 wt % of titanium (Ti), 0.01 to 0.10 wt % of niobium (Nb), and the balance of iron (Fe) and inevitable impurities; having a tensile strength (TS) of 550 MPa or greater, a yield strength (YS) of 300 MPa or greater, and an elongation (EL) of 20% or greater; and having a dual-phase structure of ferrite and martensite.

Abstract: The present invention relates to tool steels which present an extremely high conductivity while maintaining high levels of mechanical properties the manufacturing process thereof. Tool steels of the present invention are able to undergo low temperature hardening treatments with good homogeneity of the microstructure and can be obtained at low cost.

Abstract: A method for producing a molded article includes the steps of: preparing a first steel plate and a second steel plate. The first steel plate and the second steel plate are joined to each other, thereby preparing a joined steel plate. The joined steel plate is heated at a temperature between 910° C. and 950° C. The heated joined steel plate is then subjected to hot-press molding, thereby preparing an intermediate molded article; and cooling the intermediate molded article, wherein the first steel plate has a tensile strength (TS) higher than that of the second steel plate.

Abstract: A powder metallurgy wear-resistant tool steel includes chemical components by mass percent of: V: 12.2%-16.2%, Nb: 1.1%-3.2%, C: 2.6%-4.0%, Si: ?2.0%, Mn: 0.2%-1.5%, Cr: 4.0%-5.6%, Mo: ?3.0%, W: 0.1%-1.0%, Co: 0.05%-0.5%, N: 0.05%-0.7%, with balance iron and impurities; wherein a carbide component of the powder metallurgy wear-resistant tool steel is an MX carbide with a NaCl type face-centered cubic lattice structure; wherein an M element of the MX carbide comprises V and Nb, and an X element comprises C and N.

Abstract: A spring steel according to the present embodiment has a chemical composition consisting of, in mass %, C: 0.4 to 0.7%, Si: 1.1 to 3.0%, Mn: 0.3 to 1.5%, P: 0.03% or less, S: 0.05% or less, Al: 0.01 to 0.05%, rare earth metal: 0.0001 to 0.002%, N: 0.015%, O or less: 0.0030% or less, Ti: 0.02 to 0.1%, with the balance being Fe and impurities. In the spring steel, the number of oxide inclusions having an equivalent circular diameter of equal to or greater than 5 ?m is equal to or less than 0.2/mm2, the oxide inclusions each being one of an Al-based oxide, a complex oxide containing REM, O and Al, and a complex oxysulfide containing REM, O, S, and Al. Further, a maximum value among equivalent circular diameters of the oxide inclusions is equal to or less than 40 ?m.

Abstract: This welded structure comprises a weld metal which contains C, Si, Mn, Cr, Mo, V, Nb, N and O in prescribed amounts respectively with the balance being Fe and unavoidable impurities and which exhibits an A value of 200 or more and a Z value of 0.05 or more. The A value is calculated from the element contents of the weld metal according to the formula: A value=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×104. The Z value is calculated according to the formula: Z value=N×[insol. V] [wherein N (particles/?m) is the number density of carbide particles present in a prior austenite grain boundary per unit grain boundary in the stress-relief annealed weld metal, and [insol. V] is the concentration of compound-type V as determined by analyzing an extraction residue of the stress-relief annealed weld metal].

Abstract: A turbine rotor includes a high- and low-temperature side rotor base materials. The high- and low-temperature materials include concavities and grooves. The turbine rotor has an enclosed space formed by the concavity of the high- and low-temperature materials being disposed opposingly, and a gap formed by the grooves of the high- and low-temperature materials being disposed opposingly. The turbine rotor contains a buildup welding section formed between the high- and low-temperature materials, which has the same composition as that of the high- or low-temperature material, and has a penetration bead on the enclosed space side, and the gap contains a weld metal filled therein. Thus, a stable penetration bead can be formed in a dissimilar material welded rotor combining two kinds of alloy materials with different thermal properties, and then generation of a non-welded portion of a butting section that becomes a start point of fracture can be suppressed.

Abstract: A formable galvanized steel sheet includes, in terms of % by mass, 0.05 to 0.3% of C, 0.01 to 2.5% of Si, 0.5 to 3.5% of Mn, 0.003 to 0.100% of P, 0.02% or less of S, 0.010 to 1.5% of Al, and 0.01 to 0.2% in total of at least one element selected from Ti, Nb and V, the remainder being Fe and unavoidable impurities, having a microstructure composed of, in terms of area fraction, 20 to 87% of ferrite, 3 to 10% in total of martensite and residual austenite, and 10 to 60% of tempered martensite, and a second phase composed of the martensite, residual austenite, and tempered martensite having an average crystal grain diameter of 3 ?m or less, and having a ratio of absorption energy AE to tensile strength TS (AE/TS) not less than 0.063.

Abstract: Provided is a mold steel for plastic injection that is excellent in fatigue strength and tensile strength and available for long term use, where the mold steel includes: 0.15 to 0.40 wt. % of carbon (C), 0.15 to 0.50 wt. % of silicon (Si), 0.70 to 1.50 wt. % of manganese (Mn), 0.50 to 1.20 wt. % of nickel (Ni), 1.50 to 2.50 wt. % of chrome (Cr), 0.25 to 0.70 wt. % of molybdenum (Mo), 0.20 wt. % or less of vanadium (V), 0.010 wt. % or less of boron (B), and a trace of iron (Fe) and a plurality of impurities.

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: The invention relates to a steel and to a flat steel product produced therefrom that have optimized mechanical properties and at the same time can be produced at low cost, without having to rely for this on expensive alloying elements that are subject to great fluctuations with regard to their procurement costs. The steel and the flat steel product have for this purpose the following composition according to the invention (in % by weight): C: 0.11-0.16%; Si: 0.1-0.3%; Mn: 1.4-1.9%; Al: 0.02-0.1%; Cr: 0.45-0.85%; Ti: 0.025-0.06%; B: 0.0008-0.002%, the remainder Fe and impurities that are unavoidable for production-related reasons, which include contents of phosphorus, sulfur, nitrogen or molybdenum as long as the following respectively apply for their contents: P: ?0.02%, S: ?0.003%, N: ?0.008%, Mo: ?0.1%. Similarly, the invention relates to a method for producing a flat steel product that consists of a steel according to the invention.

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 forging heat resistant steel of an embodiment contains in percent by mass C: 0.05-0.2, Si: 0.01-0.1, Mn: 0.01-0.15, Ni: 0.05-1, Cr: 8 or more and less than 10, Mo: 0.05-1, V: 0.05-0.3, Co: 1-5, W: 1-2.2, N: 0.01 or more and less than 0.015, Nb: 0.01-0.15, B: 0.003-0.03, and a remainder comprising Fe and unavoidable impurities.

Abstract: A steel sheet for hot pressing use according to the present invention has a specified chemical component composition, wherein some of Ti-containing precipitates contained in the steel sheet, each of which having an equivalent circle diameter of 30 nm or less, have an average equivalent circle diameter of 6 nm or less, the precipitated Ti amount and the total Ti amount in the steel fulfill the relationship represented by formula (1) shown below, and the sum total of the fraction of bainite and the fraction of martensite in the metal microstructure is 80 area % or more. Precipitated Ti amount (mass %)?3.4[N]?0.5×[(total Ti amount (mass %))?3.4[N]]??(1) (In the formula (1), [N] represents the content (mass %) of N in the steel.

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 dual phase or complex phase steel strip showing no tigerstripes. The steel strip having an ultimate tensile strength Rm classifying for 1000 MPa steel category, includes (in mass percent) C 0.09-0.19%; Mn 1.9-2.6%; Si at most 0.1%; Cr 0.4-0.8%; Mo at most 0.3%; Ni at most 0.4%; Al 0.02-1.3%; and optionally one or more of the following elements: Nb at most 0.08%; P equal to or more than 0.0005%; N equal to or less than 0.015%; Ti equal to or less than 0.1%; V equal to or less than 0.1%; B equal to or less than 0.01%; wherein the sum of Cr, Mo and Ni is at least 0.5%; the balance being Fe and inevitable impurities.

Abstract: Provided are: a boron-added high strength steel for bolt excellent in delayed fracture resistance even having a tensile strength of 1100 MPa or more without addition of large amounts of expensive alloy elements such as Cr and Mo: and a high strength bolt made from the boron-added high strength steel for bolt. The high strength steel for bolt contains C of 0.23% to less than 0.40%, Si of 0.23% to 1.50%, Mn of 0.30% to 1.45%, P of 0.03% or less (excluding 0%), S of 0.03% or less (excluding 0%), Cr of 0.05% to 1.5%, V of 0.02% to 0.30%, Ti of 0.02% to 0.1%, B of 0.0003% to 0.0050%, Al of 0.01% to 0.10%, and N of 0.002% to 0.010%, with the remainder being iron and inevitable impurities. The steel has a ratio ([Si]/[C]) of the Si content [Si] to the C content [C] of 1.0 or more and has a ferrite-pearlite mixed microstructure.

Abstract: A steel wire rod or steel bar as hot-rolled, including: by mass %: C: 0.1 to 0.6%, Si: 0.01 to 1.5%, Mn: 0.05 to 2.5%, Al: 0.015 to 0.3%, and N: 0.0040 to 0.0150%, and P: limited to 0.035% or less and S: limited to 0.025% or less, and the balance substantially consisting of iron and unavoidable impurities, wherein a depth of d (mm) from the surface of the surface layer region with 20 HV 0.2 or more higher, relative to HV 0.2 that is the average hardness in the region where the depth from the surface is from sectional radius R×0.5 (mm) to the center satisfies the formula (1); the steel structure of the surface layer region has a ferrite fraction of 10% or less by area ratio, with the balance being one or two or more of martensite, bainite and pearlite; the steel structure where the depth from the surface is from the sectional radius R×0.

Abstract: A steel article is provided for improved wear resistance due to optimized hardness, toughness and temper resistance. In one exemplary embodiment, the steel article may have a composition including about 0,2 to 0.43 percent by weight of carbon, about 0.5 to about 3.0 percent by weight of silicon, about 0.01 to about 3.0 percent by weight of chromium, and 0.43 to about 2.5 percent by weight of vanadium.

Abstract: A steel sheet for hot pressing use according to the present invention has a specified chemical component composition, wherein some of Ti-containing precipitates contained in the steel sheet, each of which having an equivalent circle diameter of 30 nm or less, have an average equivalent circle diameter of 3 nm or more, the precipitated Ti amount and the total Ti amount in the steel fulfill the relationship represented by formula (1) shown below, and the sum total of the fraction of bainite and the fraction of martensite in the metal microstructure is 80 area % or more. Precipitated Ti amount (mass %)?3.4[N]>0.5×[total Ti amount (mass %)?3.4[N]]??(1) (In the formula (1), [N] represents the content (mass %) of N in the steel.

Abstract: According to the present invention, it is possible to obtain steel for nitrocarburizing having a predetermined chemical composition, a bainite area ratio exceeding 50% and excellent machinability by cutting before nitrocarburizing, and having strength and toughness equivalent to conventional steel, such as SCr420 carburized steel material, and excellent fatigue properties after nitrocarburizing.

Abstract: A cast alloy is generally provided, along with methods of forming the cast alloy and components constructed from the cast alloy (e.g., stationary components of a turbine). The cast alloy can include, by weight, 0.12% to 0.20% carbon, 0.50% to 0.90% manganese, 0.25% to 0.60% silicon, 0.10% to 0.50% nickel, 1.15% to 1.50% chromium, 0.90% to 1.50% molybdenum, 0.70% to 0.80% vanadium, 0.0075% to 0.060% titanium, 0.008% to 0.012% boron, the balance iron, optionally low levels of other alloying constituents, and incidental impurities.

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: Provided is bearing steel excellent in post spheroidizing-annealing workability and in post quenching-tempering hydrogen fatigue resistance property. 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; 0.0020% or less O; and 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 rolling contact fatigue life and also the workability such as cuttability and forgeability of the material.

Abstract: Provided is a wear resistant steel including 2.6 wt % to 4.5 wt % of manganese (Mn), carbon (C) satisfying (6-Mn)/50?C?(10-Mn)/50, 0.05 wt % to 1.0 wt % of silicon (Si), and iron (Fe) as well as other unavoidable impurities as a remainder, wherein a Brinell hardness of a surface portion is in a range of 360 to 440. The wear resistant steel further includes at least one component selected from the group consisting of 0.1 wt % or less (excluding 0 wt %) of niobium (Nb), 0.1 wt % or less (excluding 0 wt %) of vanadium (V), 0.1 wt % or less (excluding 0 wt %) of titanium (Ti), and 0.02 wt % or less (excluding 0 wt %) of boron (B) to complement the performance thereof. The wear resistant steel is characterized in that a microstructure includes martensite in an amount of 90% or more, and an average packet diameter of the martensite is 20 ?m or less.

Abstract: The present invention provides a high-tensile steel material having a tensile strength of the 550 MPa class or more which can simultaneously raise the strength and toughness of the heat affected zone of weld to equal those of the matrix and a method of production of the same, that is, a high-tensile steel material with excellent weldability and toughness and with tensile strength of the 550 MPa class or more containing, by mass %, C: 0.005 to 0.10%, W: 0.10 to 3.0%, Nb: 0.010 to 0.080%, and V: 0.010 to 0.50%, limiting the Ti to less than 0.005%, satisfying equation; EC=2[C]?[Nb]/9?[V]/12>0.020, having an amount of precipitation of W contained in the steel material, in terms of analytical value obtained by quantitative analysis of potential electrolysis extraction residue by fluorescent X-ray analysis, of 0.0050% or less, and having 60% or more of its structural composition in a cross-section of the steel as a bainite structure.

Abstract: A steel for welding includes steel components in which PCTOD is less than or equal to 0.065%, CeqH is less than or equal to 0.225%, FB is greater than or equal to 0.0003%, and Bp is 0.09% to 0.30%. In the steel for welding, in a thickness center portion of a cross-section in a thickness direction, the number of oxide particles having an equivalent circle diameter of 2 ?m or greater is less than or equal to 20 particles/mm2 and the number of Ti oxides having an equivalent circle diameter of 0.05 ?m to 0.5 ?m is 1.0×103 particles/mm2 to 1.0×105 particles/mm2.

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: A hard weld overlay which is resistant to cracking when re-heated, and a method for designing such alloys, is disclosed. The alloys are able to resist re-heat cracking through prevention of the precipitation and/or growth of embrittling carbide, borides, or borocarbides at elevated temperatures. In one embodiment, the thermodynamics of the alloy system possess only primary carbides and secondary ferrite carbides.

Abstract: The present invention provides high strength steel pipe for line pipe superior in low temperature toughness suppressed in drop of toughness of the HAZ and a method of production of the same, more particularly high strength steel plate for line pipe used as a material for high strength steel pipe for line pipe and a method of production of the same, in particular high strength steel pipe for line pipe superior in low temperature toughness characterized in that the chemical compositions of the base metal is, by mass %, C: 0.020 to 0.080%, Si: 0.01 to 0.50%, Mo: 0.01 to 0.15%, Al: 0.0005 to 0.030%, and Nb: 0.0001 to 0.030% contained in a range of C+0.25Si+0.1Mo+Al+Nb: 0.100% or less and the mixture of austenite and martensite present along prior austenite grain boundaries of the reheated part of the heat affected zone has a width of 10 ?m or less and a length of 50 ?m 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: 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 an alloy steel for hot forging and a heat treatment method thereof, more particularly, an alloy steel for hot forging and a heat treatment method thereof, which includes iron as a base material, and about 0.08 to 0.13% by weight of carbon (C), about 1.3 to 1.5% by weight of manganese (Mn), and about 0.1 to 0.3% by weight of molybdenum (Mo), based on a total weight of the alloy steel. As such, a tempering process can be omitted to reduce process costs, while still providing excellent strength and toughness as compared to the alloy steel in the related art.

Abstract: A steel having excellent formability, fatigue endurance after quenching, low temperature toughness, resistance for hydrogen embrittlement, and corrosion fatigue endurance. A method includes heating a steel slab at 1160° C. to 1320° C., hot-finish-rolling the steel slab at a finisher delivery temperature of 750° C. to 980° C., and then coiling the hot-rolled steel at a coiling temperature of 560° C. to 740° C. after slow cooling for a time of 2 seconds or more to produce a hot-rolled steel strip having a structure in which the ferrite grain diameter df corresponding to a circle is 1.1 ?m to less than 1.2 ?m and the ferrite volume fraction Vf is 30% to 98%, the steel slab containing 0.18 to 0.29% of C, 0.06 to 0.45% of Si, 0.91 to 1.85% of Mn, 0.019% or less of P, 0.0029% or less of S, 0.015 to 0.075% of sol. Al, 0.0049% or less of N, 0.0049% or less of O, 0.0001 to 0.0029% of B, 0.001 to 0.019% of Nb, 0.001 to 0.029% of Ti, 0.001 to 0.195% of Cr, and 0.001 to 0.

Abstract: Disclosed are heat-hardened steel with excellent crashworthiness and a method for manufacturing heat-hardenable parts using the same. The heat-hardened steel according to the invention comprises, based on wt %; C: 0.12-0.8%; Cr: 0.01-2%; Mo: 0.2% or less; B: 0.0005-0.08%; Ca: 0.01 or less; Sb: 1.0% or less; and Ti and/or Nb: 0.2%; and the reminder being Fe and inevitable impurities. In addition, the heat-treatment hardening steel satisfies anyone of following conditions i)-iv), wherein condition i) comprises Si: 0.5-3%; Mn: 1-10% and Al: 0.05-2%; condition ii) comprises Si: 1% or less; Mn: 0.5-5%; Al: 0.1-2.5%; and Ni: 0.01-8%; condition iii) comprises Si: 0.5-3%; Mn: 1-10%; Al: 0.1% or less; and Ni: 0.01-8%; and condition iv) comprises Si: 0.5-3%; Mn: 1-10%; Al: 0.1-2.5%; and Ni: 0.01-8%.

Abstract: There is provided a hot press-formed product, including a thin steel sheet formed by a hot press-forming method, and having a metallic structure that contains martensite at 80% to 97% by area and retained austenite at 3% to 20% by area, the remainder structure of which is at 5% by area or lower, whereby balance between strength and elongation can be controlled in a proper range and high ductility can be achieved.

Abstract: A low-chromium hot-work tool steel consisting of (in wt-%): C 0.08-0.40, N 0.015-0.30, C+N 0.30-0.50, Cr 1-4, Mo 1.5-3, V 0.8-1.3, Mn 0.5-2, Si 0.1-0.5, optionally Ni<3, Co?5, B<0.01, Fe balance apart from impurities, and a process for making a low-chromium hot-work tool steel article having increased tempering resistance.

Abstract: There is provided a hot press-formed product, including a steel sheet formed by a hot press-forming method, and having a metallic structure that contains ferrite at 30% to 80% by area, bainitic ferrite at lower than 30% by area (not including 0% by area), martensite at 30% by area or lower (not including 0% by area), and retained austenite at 3% to 20% by area, whereby balance between strength and elongation can be controlled in a proper range and high ductility can be achieved.

Abstract: There is provided a hot press-formed product, including a thin steel sheet formed by a hot press-forming method, and having a metallic structure that contains bainitic ferrite at 70% to 97% by area, martensite at 27% by area or lower, and retained austenite at 3% to 20% by area, the remainder structure of which is at 5% by area or lower, whereby balance between strength and elongation can be controlled in a proper range and high ductility can be achieved.

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: A steel for an oil well pipe, having high strength and excellent SSC resistance, consists of, by mass %, C: 0.30 to 0.60%, Si: 0.05 to 0.5%, Mn: 0.05 to 1.0%, Al: 0.005 to 0.10%, Cr+Mo: 1.5 to 3.0%, wherein Mo is 0.5% or more, V: 0.05 to 0.3%, Nb: 0 to 0.1%, Ti: 0 to 0.1%, Zr: 0 to 0.1%, N (nitrogen): 0 to 0.03%, Ca: 0 to 0.01%, and the balance Fe and impurities; P 0.025% or less, S 0.01% or less, B 0.0010% or less and O (oxygen) 0.01% or less. The method involves heating the steel at 1150° C. or more; producing a seamless steel pipe by hot working; water-cooling the pipe to a temperature in a range of 400 to 600° C. immediately after finishing the working; and subjecting the pipe to a heat treatment for bainite isothermal transformation in a range of 400 to 600° C.

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: A piston ring includes: a refined steel including: carbon C in a range of 0.20% mass to 0.90% mass, silicon Si in a range of 0.10% mass to less than 0.60% mass, manganese Mn in a range of 0.20% mass to 1.50% mass, chromium Cr in a range of 0.30% mass to 2.00% mass, and a remnant including: iron Fe, and an unavoidable impurity. A parameter A calculated from the following expression (1) based on contents of the Si, Mn and Cr is 9.0 or less: parameter A=8.8 Si+1.6 Mn+1.7 Cr—expression (1). A parameter B calculated from the following expression (2) based on contents of the C, Si, Mn and Cr is 10.8 or more: parameter B=36 C+4.2 Si+3.8 Mn+4.5 Cr—expression (2).

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: Disclosed is a carburized machine part which is free from the problem of decreased strength at edge-shaped parts due to excess introduction of carbon. The machine part is produced by processing a case hardening steel of the alloy composition consisting essentially of, by weight %, C: 0.1-0.3%, Si: 0.5-3.0%, Mn: 0.3-3.0%, P: up to 0.03%, S: up to 0.03%, Cu: 0.01-1.00%, Ni: 0.01-3.00%, Cr: 0.3-1.0%, Al: up to 0.2% and N: up to 0.05% and the balance of Fe and inevitable impurities, and satisfying the following condition: [Si %]+[Ni %]+Cu %]?[Cr %]>0.5 and carburizing by vacuum carburization.

Abstract: Compositions for Chromium-free hardfacing welding consumables are provided that include between approximately 0.3% and approximately 1.5% Carbon, between approximately 0.2% and approximately 2.5% Manganese, between approximately 0.3% and approximately 1.3% Silicon, between approximately 1.3% and approximately 5.5% Boron, between approximately 1.0% and approximately 4.0% Nickel, between approximately 1.0% and approximately 6.0% of at least one of Titanium and Niobium, and between approximately 0.1% and approximately 2.0% Tungsten and/or Molybdenum. Additional welding consumable compositions and weld deposit compositions are also provided to provide hardfacing materials with little or no Chromium content.

Abstract: A steel sheet according to the present invention has tensile strength of 980 MPa or more, exerts a high-yield ratio, and has excellent workability (in detail, strength-ductility balance). The steel sheet contains: C: 0.06-0.12% (excluding 0.12%); Si: 0.2% or less; Mn: 2.0-3.5%; at least one element selected from the group consisting of Ti, Nb, and V of 0.01-0.15% in total; B: 0.0003-0.005%; P: 0.05% or less; S: 0.05% or less; Al: 0.005-0.1%; N: 0.015% or less; and the balance is iron and unavoidable impurities, in which the content of ferrite is more than 5% to 15% or less, that of martensite is 25-55%, and the total content of bainite and tempered martensite is 30% or more to less than 70%, based on the whole microstructure, and in which the average crystal grain size of the ferrite is 3.0 ?m or less.

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: A steel material which is suitable for hot press working or hot three-dimensional bending and direct quench and which can be used to manufacture a high-strength formed article with sufficient quench hardening even by short time heating at a low temperature has a chemical composition comprising, in mass percent, C: 0.05-0.35%, Si: at most 0.5%, Mn: 0.5-2.5%, P: at most 0.03%, S: at most 0.01%, sol. Al: at most 0.1%, N: at most 0.01%, and optionally at least one element selected from the group consisting of B: 0.0001-0.005%, Ti: 0.01-0.1%, Cr: 0.18-0.5%, Nb: 0.03-0.1%, Ni: 0.18-1.0%, and Mo: 0.03-0.5% and has a steel structure in which the spheroidization ratio of carbides is 0.60-0.90.