Abstract: The present invention lowers the strength before nitriding to improve the machinability, while deepens the effective hardened case of the nitrided case for improving the fatigue strength. It provides steel for nitriding use containing, by mass %, C: 0.05 to 0.30%, Si: 0.003 to 0.50%, Mn: 0.4 to 3.0%, Cr: 0.2 to 0.9%, Al: 0.19 to 0.70%, V: 0.05 to 1.0%, and Mo: 0.05 to 0.50%, having contents of Al and Cr satisfying 0.5%?1.9Al+Cr?1.8%, and having a balance of Fe and unavoidable impurities.

Abstract: Steel for nitrocarburizing includes, by mass %, C: 0% to less than 0.15%; Si: 0.01% to 1.00%; Mn: 0.01% to 1.00%; S: 0.0001% to 0.050%; Al: 0.0001% to 0.050%; Ti: more than 0.50% to 1.50%; N: 0.0005% to 0.0100%; and the balance consisting of Fe and inevitable impurities, in which P is limited to 0.050% or less; O is limited to 0.0060% or less; and the amount of Ti [Ti %], the amount of C [C %], the amount of N [N %], and the amount of S [S %] satisfy 0.48<[Ti %]?47.9×([C %]/12+[N %]/14+[S %]/32)?1.20.

Abstract: A bearing part having long life against rolling contact fatigue, excellent in anti-crack strength and restricted in an increase of aged dimensional change, a heat treatment method thereof, and a rolling bearing including the bearing part are obtained. Steel for a bearing part is subjected to carbonitriding at a carbonitriding temperature exceeding the A1 transformation temperature, and cooled to a temperature lower than the A1 transformation temperature. The steel is reheated to a temperature for quenching that is not lower than the A1 transformation temperature but lower than the carbonitriding temperature, and then quenched.

Abstract: A carburized and tempered hardened steel structure includes an iron based steel alloy including from about 3.7 to about 6 wt % copper, from 6 to about 10 wt % cobalt and from about 1 to about 10 wt % of non-ferrous secondary carbide formation elements selected from any of the group consisting of chromium, molybdenum, vanadium and combinations thereof. At least a percentage of the secondary carbide formation elements are in the form of metal carbides attached to nucleation sites on copper precipitates within a carburized portion of the structure, and wherein the copper precipitates are at least one of i) characterized by a mean copper precipitate radius of from about 0.1 nm to about 5 nm, or ii) characterized by a density of about 2.7×1018 per cubic centimeter.

Abstract: A method for refining the texture of a ferrous material. The method includes a first step and a second step. The first step includes a step of making carbide particles in a portion of a base material smaller. The second step includes a step of nitriding at least a part of said portion.

Abstract: Provided is a maraging steel strip which has such a composition that can reduce the content of TiN acting as the starting point of fatigue fracture in a high-cycle region, and the bending fatigue strength of which has been improved by the precipitation hardening effect yielded by precipitating coherent nitrides in the nitrided structure. A maraging steel strip produced by nitriding a managing steel which contains by mass, C: 0.01% or less, Si: 0.1% or less, Mn: 0.1% or less, P: 0.01% or less, S: 0.005% or less, Ni: 8.0 to 22.0%, Cr: 0.1 to 8.0%, Mo: 2.0 to 10.0%, Co: 2.0 to 20.0%, Ti: 0.1% or less, Al: 2.5% or less, N: 0.03% or less, and O: 0.005% or less, with the balance being Fe and unavoidable impurities, wherein Baker-Nutting orientation relationship with an orientation difference within 10° exists between the Cr nitride precipitated in the nitrided layer and the matrix martensite.

Abstract: A steel composition which has good nitridability, in particular for the manufacture of piston rings and cylinder liners, contains the following elements in the following quantities expressed with respect to 100 weight % of the steel composition: 0.5-1.5 weight % Al, 0.5-1.2 weight % C, 68.2-96.9 weight % Fe, 0.1-3.0 weight % Mn and 2.0-10.0 weight % Si. It can be manufactured by producing a melt of starting materials and casting the melt into a prepared mould. Nitriding the steel composition obtained results in a nitrided steel composition produced by gravity casting manufacturing with properties that surpass those of hardened and tempered spheroidal graphite.

Abstract: In the steel for a surface layer hardening which is treated with carburizing in a temperature range of 800° C. to 900° C., chemical composition thereof contains, by mass %, C: 0.10% to 0.60%, Si: 0.01% to 2.50%, Mn: 0.20% to 2.00%, S: 0.0001% to 0.10%, Cr: 2.00% to 5.00%, Al: 0.001% to 0.50%, N: 0.0020% to 0.020%, P: 0.001% to 0.050%, and O: 0.0001% to 0.0030%; the remaining portion thereof includes Fe and unavoidable impurities; and the total amount of Cr, Si, and Mn satisfies, by mass %, 2.0?Cr+Si+Mn?8.0.

Abstract: To improve corrosion resistance in wet environments, for a martensitic cast steel material obtained at a predetermined composition ratio and martensitic steel casting products, and to provide a martensitic cast steel material that is appropriate for various types of molds and dies, mechanical parts, etc., and a manufacturing method for martensitic steel casting products. Nickel, Ni, of 5 to 10 mass %, silicon, Si, of 0.5 to 5 mass %, manganese, Mn, of 0.01 to 1 mass %, carbon, C, of 0.2 to 2 mass % and a remaining part consisting of iron, Fe, and incidental impurities are employed, and further chromium, Cr, of 1 to 10 mass % is added to obtain a martensitic cast steel material for which a martensitic transformation finish temperature (Mf point) is below freezing. Further, a cast steel material that contains vanadium V of 0.1 to 5 mass % in addition to the above elements of the material is also obtained.

Abstract: A rolling apparatus including an external member having a raceway surface on an inner peripheral surface thereof, an internal member having a raceway surface on an outer peripheral surface thereof, and a plurality of rolling elements which are rotatably provided between the raceway surface of the external member and the raceway surface of the internal member. A surface of at least one of the internal member, the external member, and the rolling elements is subjected to carbonitriding or nitriding; an area percentage of a nitride containing Si and Mn is 1% or more and 20% or less; surface hardness is HV750 or more. When depth from the raceway surface or depth from a rolling surface of the rolling element is defined as Z and diameter of the rolling element is defined as d, hardness at Z=0.045 d is HV650 to 850, and hardness at Z=0.18 d is HV400 to 800.

Abstract: A method for processing parts for kitchen tools in order to protect the parts from scratches, includes sequentially: a nitridation step, optionally including a nitrocarburizing step, between 592 and 750° C. in order to promote the formation of a nitrogen austenite layer; and a processing step for promoting the conversion of at least a portion of the nitrogen austenite into a phase with reinforced hardness.

Abstract: A rolling bearing comprises an outer ring, an inner ring and rolling elements rotatably disposed between the outer and inner rings. At least a member selected from the outer ring, inner ring and rolling elements has C content of 0.2 or more and 0.6 or less wt %, Cr content of 2.5 or more and 7.0 or less wt %, Mn content of 0.5 or more and 2.0 or less wt %, Si content of 0.1 wt % or more and 1.5 or less wt %, and Mo content of 0.5 or more and 3.0 or less wt %. Further, a carburizing or carbo-nitriding treatment, a quenching treatment and a tempering treatment are applied to the selected member. Furthermore, retained austenite on a surface thereof is 15% or more and 45% or less vol. %, and the surface hardness thereof is HRC60 or more.

Abstract: A steel-made rolling-contact shaft with a joint claw improved in both the rolling contact fatigue life at the raceway and the static fracture strength (torsional strength) at the claw includes a joint claw at one end, and has a portion of the outer cylindrical surface functioning as a raceway of a needle roller qualified as a rolling element of a needle bearing. The joint claw is subjected to tempering by induction heating. A nitrogen-enriched layer is formed at the surface layer of the rolling-contact shaft with a joint claw. The grain size number of austenite grains in the nitrogen-enriched layer exceeds number 10. The hydrogen content of the rolling-contact shaft with a joint claw is not more than 0.5 ppm.

Abstract: A carbonitrided part, where a base steel contains, in mass percent, C: 0.10 to 0.35%, Si: 0.15 to 1.0%, Mn: 0.30 to 1.0%, Cr: 0.40 to 2.0%, S?0.05%, and according to need further Mo?0.50%, with the balance being Fe and impurities, and in the region to a position of effective hardening depth from the surface of a hardened layer of the carbonitrided part, iron nitride particles of ?-Fe3N and/or ?-Fe2N are dispersed, and retained austenite is decomposed into bainitic ferrite, Fe3C, and ??-Fe16N2 has excellent abrasion strength and high pitting strength, although the base steel is a low-cost one with less content of Mo of an expensive alloy element or without addition of Mo. This carbonitrided part can be produced, for example, by subjecting the base steel part to carburizing in which the base steel part is held in a carburizing atmosphere at 900 to 950° C. and successively to carbonitriding in which the base steel part is held in a carbonitriding atmosphere with a nitrogen potential of 0.2 to 0.

Abstract: A nitrided steel product or thin cast steel strip comprising, 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 about 0.20%, and between 0.01 and 0.075% nitrogen, and having a majority of the microstructure comprised of bainite and acicular ferrite, having more than 70% niobium in solid solution prior to nitriding and having yield strength between 650 MPa and 800 MPa and tensile strength between 750 MPa and 900 MPa.

Abstract: There is provided a bearing constituent member capable of achieving a long life of a rolling bearing and securing sufficient static loading capacity and dimensional stability and a production process thereof as well as a rolling bearing having a long life and exhibiting sufficient static loading capacity and dimensional stability. A workpiece obtained from a steel containing 3.2 to 5.0% by mass of Cr and 0.05% by mass or more to less than 0.5% by mass of V is subjected to a heat treatment such as a carbonitriding treatment. Thereby, the following are achieved: the content of C in the surface layer ranging from the surface of the bearing constituent member of the rolling bearing to 10 ?m is 1.1 to 1.6% by mass, Vickers hardness at the position of a depth of 50 ?m from the surface is 740 to 900 (Rockwell C hardness is 62 to 67), the ? amount at the position of a depth of 10 ?m from the surface is 20 to 55% by volume, particles composed of vanadium nitride having a particle diameter of 0.

Abstract: Nitriding process of a steel strip is performed. Next, annealing is performed to form a forsterite based glass coating film at a surface of the steel strip. Heating is performed up to 1000° C. or more in a mixed gas atmosphere containing H2 gas and N2 gas, and a rate of N2 gas is 20 volume % or more, next, the atmosphere is switched into H2 gas atmosphere at the temperature of 1000° C. or more and 1100° C. or less, when the annealing is performed. An oxygen potential P (H2O)/P (H2) is set to be 0.05 to 0.3 when the temperature is 850° C. or less during the heating in the mixed gas atmosphere.

Abstract: A steel wire has tempered martensite, comprises, as essential components, by mass, C: 0.53 to 0.68%; Si: 1.2 to 2.5%; Mn: 0.2 to 1.5%; Cr: 1.4 to 2.5%; Al: 0.05% or less; further comprises, as a selective component, Ni: 0.4% or less; V: 0.4% or less; Mo: 0.05 to 0.5%; or Nb: 0.05 to 0.5%; and further comprises remainder essentially consisting of Fe and inevitable impurities, wherein the grain size number of prior austenite is 11.0 or larger, and the proof stress ratio (?0.2/?B), namely, a ratio of 0.2% proof stress (?0.2) to tensile strength (?B) is 0.85 or lower. Satisfying the above requirements makes it possible to produce a steel wire for high-strength spring excellent both in workability (cold workability), and in sag resistance and fatigue properties.

Abstract: Obtain a bearing's component, a heat treatment method thereof, and a rolling bearing having a long life against rolling contact fatigue and high anti-crack strength, and suppressed long-term dimensional variation rate. The bearing's component is carbonitrided at a carbonitriding temperature higher than an A1 transformation point of steel for the bearing's component and then cooled to a temperature lower than the A1 transformation point, and subsequently, using a heat treatment apparatus that successively moves and heats each individual bearing's component, reheated to a range of quenching temperature of no less than the A1 transformation point and less than the carbonitriding temperature to be quenched.

Abstract: The present invention relates to a steel material giving more effective case hardening for improving the fatigue strength and is characterized by containing, by mass %, C: 0.01 to 0.3%, Si: less than 0.1%, Mn: 0.4 to 3%, Cr: 0.5 to 3%, and Al: 0.01 to 0.3%, further containing one or both of Mo: 0.2 to 1.5%, and V: 0.05 to 1.0%, having a balance of Fe and unavoidable impurities, and comprising a structure having 50% or more of bainite.

Abstract: Providing an iron and steel material having quenched surface part, avoiding oxidation of a compound layer formed on the surface of the iron and steel material due to quenching, its production method, and an induction-quenched component. A quenched iron and steel material 10 comprises an iron and steel material 11, a compound layer 12 formed on the iron and steel material 11, and an antioxidant cover layer 13 formed on the compound layer 12. The iron and steel material 11 has a hardened layer having a given depth, and the surface of the iron and steel material 11 has enhanced hardness.

Abstract: The present invention relates to a manufacturing process of a structural component for a motor vehicle, wherein a plate bar is heated, is fed to a die in the heated state and is shaped in the die. The process is characterized in that the plate bar is subjected to a nitriding process before the shaping. Furthermore, a plate bar for hot-forming for manufacturing a structural component for a motor vehicle is described, wherein the surface of the plate bar has a nitrided layer. Finally, the present invention relates to a structural component of a motor vehicle, which is manufactured by hot forming from a plate bar having a nitrided layer.

Abstract: A method for improving corrosion resistance in FNC cast iron substrates without the need for additional coating or painting. The exemplary methods remove a portion of the FNC coating applied to a cast iron substrate, preferably through polishing, to expose the epsilon phase portion of the compound area. The epsilon phase portion is thought to provide improved corrosion protection as compared to non-polished FNC cast iron substrates. One exemplary product that may be provided with improved corrosion protection according to the above method is a brake rotor having a FNC treatment.

Abstract: A cost effective system, method and apparatus adapted to provide a nitride layer on stainless steel used for the manufacture of consumer electronic products. In addition to providing a durable, hard surface that is both scratch and impact resistant, the nitride layer allows for the natural surface color and texture of the underlying stainless steel to remain visible to the user. It is this natural surface color and texture of the stainless steel that adds to the aesthetically pleasing appearance of the consumer electronic product thereby enhancing the user's overall experience.

Abstract: Steel for machine structure use for surface hardening containing, by mass %, C: 0.3 to 0.6%, Si: 0.02 to 2.0%, Mn: 1.5% to 3.0%, W: 0.0025 to 0.5%, Al: 0.001 to 0.5%, N: 0.003 to 0.02%, S: 0.0001 to 0.025%, P: 0.0001 to 0.03%, and O: 0.0001 to 0.0050%, having an Mn/S of 70 to 30000, and having a balance of substantially Fe and unavoidable impurities.

Abstract: It is devised to further enhance strength and straightening ability of a nitrocarburized raw material for crankshafts. A nitrocarburized raw material for crankshafts is formed so as to have a composition composed of C, Si, Mn, Cu, Ni, Cr, V, S, s-Al, Ca and N in prescribed % by mass, with the balance being Fe and inevitable impurities and having a structure of ferrite+pearlite; after smelting a steel having the foregoing composition, hot forging is performed; thereafter, a normalizing treatment is applied to the subject hot forged material at a treatment temperature in the range of from 780° C. to 850° C.; and straightening process for correcting bending to be caused due to the nitrocarburizing treatment is later applied.

Abstract: A rolling part formed by performing spheroidizing annealing, processing, carbonitriding and finishing on a steel material containing C in an amount of 0.90 mass % to 1.10 mass %, Si in an amount of more than 0.35% and up to 0.70%, Mn in an amount of less than 0.80 mass %, Cr in an amount of 1.85 mass % to 2.50 mass %, O in an amount of 12 ppm or less, and the balance of Fe and unavoidable impurities. The mean C amount on a surface is from 1.20 mass % to 1.50 mass %, and the mean N amount is from 0.10 mass % to 0.60 mass %. Deposits having a particle size of 0.1 ?m or more on the surface have a mean particle size of 0.6 ?m or less, exist as 700,000 particles or more per mm2, and have an area ratio of 10% or more. The amount of retained austenite of the surface is from 25% to 45% by volume ratio. The hardness of the surface is Hv 750 or more. The inside of the rolling part has an amount of retained austenite of 20% or less by volume ratio.

Abstract: A highly corrosion-resistant member that is equipped with: a substrate made of stainless steel; an intermediate layer coated on at least a part of a surface of the substrate; and an amorphous carbon film coated on at least a part of a surface of the intermediate layer is completed by forming the intermediate layer and amorphous carbon film at such a low temperature that a temperature of the surface of the substrate is 450° C. or less. Another highly corrosion-resistant member that is equipped with: a substrate made of stainless steel, substrate whose superficial-layer portion is subjected to nitriding treatment; and an amorphous carbon film coated on at least a part of a surface of the superficial-layer portion is completed by carrying out the nitriding treatment and a formation of the amorphous carbon film at such a low temperature that a temperature of a surface of said substrate is 450° C. or less.

Abstract: A cost effective system, method and apparatus adapted to provide a nitride layer on stainless steel used for the manufacture of consumer electronic products. In addition to providing a durable, hard surface that is both scratch and impact resistant, the nitride layer allows for the natural surface color and texture of the underlying stainless steel to remain visible to the user. It is this natural surface color and texture of the stainless steel that adds to the aesthetically pleasing appearance of the consumer electronic product thereby enhancing the user's overall experience.

Abstract: The invention relates to a method for producing corrosion-resistant surfaces of nitrated or nitrocarburated steel components, the surfaces having roughness heights (Rz) of Rz?1.5 ?m. The method comprises the following steps: oxidation of the surfaces of the nitrated or nitrocarburated components in a first oxidation step; carrying out at least a second oxidation of the component surfaces in an immediately subsequent oxidation step; polishing the component surface in a final method step, directly after the final oxidation.

Abstract: Disclosed is a hard-drawn spring which exhibits fatigue strength and sag resistance equal or superior to springs produced using an oil-tempered wire. The hard-drawn spring is produced using a steel wire containing 0.5 to 0.7 mass % of C, 1.0 to 1.95 mass % of Si, 0.5 to 1.5 mass % of Mn and 0.5 to 1.5 mass % of Cr, with the balance being Fe and inevitable impurities. In the steel wire, the number of carbides having circle-equivalent diameters of 0.1 ?m or more is 5 particles/100 ?m2 or less.

Abstract: The invention relates to a method for the plasma-nitriding of precipitation-hardenable stainless steels or stainless maraging steels. The invention also relates to a shaver cap for an electric shaver. The invention also relates to a cutting device. The invention further relates to an electric shaver comprising at least one such cutting device.

Abstract: A technique for increasing mechanical strength, such as contact pressure strength, and abrasion resistance and bending fatigue strength, of mechanical and/or structural parts by using surface hardening treatment. A quenched steel member, wherein a hard nitride layer is formed on the surface of a steel material, and an inorganic compound layer containing at least one metal oxide selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, W, Mo and Al is formed on the hard nitride layer.

Abstract: A carbonitriding method that can improve the nitrogen permeating rate to render the carbonitriding process effective includes an atmosphere control step (50), and a heating pattern control step (60). The atmosphere control step (50) includes an undecomposed NH3 partial pressure control step (51), and a CO/CO2 partial pressure control step (53). The undecomposed NH3 partial pressure control step (51) and the CO/CO2 partial pressure control step (53) are carried out in the atmosphere control step (50) such that ac* defined by the following equation (1) is at least 0.88 and not more than 1.27, and ? defined by equation (2) is at least 0.012 and not more than 0.

Abstract: The surface of a pre-molded article made of SKH51 (Fe-based alloy) is coated with a powder of Al, Cr and the like. The coating may be performed by applying a coating agent which is prepared by dispersing the powder in an organic solvent. The coating agent may contain a reducing agent. After coating, the pre-molded article is subjected to heat treatment to form a carbonized product of the metal. The pre-molded article may be further treated with nitrogen, thereby forming a layered Fe-based alloy which has a diffusion layer which is formed by the diffusion of the carbonized product, a nitrided product and AIN in the base material. Subsequently, the article may be subjected to finishing process to give a punch having a predetermined shape for use in a hot-roll forging process.

Abstract: The present invention provides a gear, continuously variable transmission, constant velocity joint, hub, or other steel part superior in surface fatigue strength compared with the past and method of production of the same, that is, provides a carbonitrided induction hardened steel part made of steel comprised of a specific composition of chemical ingredients and carbonitrided, then treated by induction hardening, the steel part characterized in that a surface N concentration is 0.1 to 0.8 mass %, a sum of an N concentration and C concentration is 1.0 to 2.0 mass %, an amount of surface residual austenite is less than 15 vol %, a depth of the incompletely hardened layer from the surface is less than 5 ?m, and a surface X-ray diffraction half width is 6.0 degrees or more, and a method of production of the same.

Abstract: A high-performance stainless steel sheet which has a high strength which is optimal for a gasket for use in high-performance engines of automobiles and motorcycles and which also has excellent workability and fatigue properties and a method for its manufacture are provided. At least in a region from the surface of the sheet up to 3 ?m in the thickness direction, nitrogen compounds of at least 10 nm and at most 200 nm are present in an amount of at least 200 per 100 ?m2. The number of nitrogen compounds of at least 10 nm and at most 200 nm in a region from the sheet surface up to 3 ?m in the thickness direction of the sheet is at least 2 times the number of nitrogen compounds of this size in the central portion of the sheet thickness.

Abstract: A ferrous abrasion resistant sliding material capable of improving seizing resistance, abrasion resistance and heat crack resistance is provided. The ferrous abrasion resistant sliding material has a martensite parent phase which forms a solid solution with carbon of 0.15 to 0.5 wt %, and the martensite parent phase contains one or more types of each special carbide of Cr, Mo, W and V dispersed therein in a total content of 10 to 50% by volume.

Abstract: Low temperature carburization of a workpiece surface is accomplished faster by impregnating the surface with a diffusion promoter prior to or during the low temperature carburization process.

Abstract: A raw steel is coated with or surrounded by a boron compound (step S1). A coating film of h-BN is formed on the surface of the raw steel. Then, the raw steel is nitrided by a nitriding gas while being heated (step S2). B from the boron compound and N from the nitriding gas are diffused into the raw steel, turning the raw steel into a steel material containing B and N. Most of B and N are present as an Fe (B, N) solid solution or an Fe (C, B, N) solid solution in the structure of the steel material. The raw steel is heated and nitrided under conditions such that B and N are contained ranging from 7 to 30 ppm by weight and ranging from 10 to 70 ppm by weight, respectively.

Abstract: A transition metal nitride obtained by nitriding a base material including an austenitic stainless steel having a Cr concentration of 25% or more includes a first layer (first nitrided layer) formed continuously on a base layer formed by the base material, having a stacked crystal structure of a nano-level including a nitride having a cubic crystal structure of M4N type, and a nitride having a hexagonal crystal structure of M2-3N type, and a second layer (second nitrided layer) formed continuously on the first layer, including a nitride having at least one kind of crystal structure out of hexagonal crystal structures of Cr2N, CrN, and M2-3N type, and a cubic crystal structure of M4N type, and being formed as a surface-nitriding-processed portion of the base material continuously in a depth direction from a surface of the base material.

Abstract: A body of iron, steel or other such ferrous material is protected from thermochemical erosion by a layer of an iron nitride having a relatively low nitrogen content. The atomic percentage of nitrogen in the iron nitride layer is no greater than 20%, and in specific embodiments is in the range of 10-15%. The nitride layer may have a layer of a refractory material deposited thereatop. Some refractory materials include metals such as chromium. The invention has specific utility for protecting gun barrels, turbines, internal combustion engines, drilling equipment, machine tools, aerospace systems and chemical reactors which are exposed to extreme conditions of temperature and pressure. Specifically disclosed is a gun barrel which incorporates the invention.

Abstract: In a surface layer of an ultra-low carbon stainless steel comprising a seal function layer in the surface layer, an ion such as a nitrogen ion is implanted to form the seal function layer. Since the ultra-low carbon stainless steel comprising the seal function layer is excellent in elasticity, sealing properties, peelability and abrasion resistance, it can make a seal material which has been used unnecessary, and can realize all stainless-made products such as seal and joint system parts.

Abstract: A steel product for a line pipe according to the invention has a composition containing, in mass %, C : 0.03% to 0.15%, Si: 0.05% to 1.0%, Mn: 0.5% to 1.8%, P: 0.015% or less, S: 0.004% or less, O: 0.01% or less, N: 0.007% or less, sol. Al: 0.01% to 0.1%, Ti: 0.024% or less, Ca: 0.0003% to 0.02%, and the balance consisting of Fe and impurities. The size of TiN in the steel product for a line pipe is at most 30 ?m. The steel product has high HIC resistance and its crack area ratio can be reduced to 3% or less.

Abstract: An oil-tempered wire that has high fatigue strength and toughness after the nitriding treatment, and a method of producing the same, and a spring using the oil-tempered wire are provided. The oil-tempered wire has a tempered martensite structure. A lattice constant of a nitride layer formed on a surface of the wire is 2.870 ? to 2.890 ? when the oil-tempered wire is nitrided. The oil-tempered wire is produced by wire drawing a steel wire and quenching and tempering the wire drawn steel wire. The quenching is performed after the radiation heating is performed at 850 to 950° C. for over 30 sec to 150 sec, and the tempering is performed at 400 to 600° C.

Abstract: A raw steel is coated with or surrounded by a boron compound (step S1). A coating film of h-BN is formed on the surface of the raw steel. Then, the raw steel is nitrided by a nitriding gas while being heated (step S2). B from the boron compound and N from the nitriding gas are diffused into the raw steel, turning the raw steel into a steel material containing B and N. Most of B and N are present as an Fe (B, N) solid solution or an Fe (C, B, N) solid solution in the structure of the steel material. The raw steel is heated and nitrided under conditions such that B and N are contained ranging from 7 to 30 ppm by weight and ranging from 10 to 70 ppm by weight, respectively.

Abstract: A method, and an article produced thereby, of providing a corroson-resistant, scratch-resistant, and stick-resistant, surface on a ferrous-metal-containing article, including forming microcavities in a ferrous-metal-containing article surface by ferritic nitrocarburization and seasoning the surface, including a non-stick agent deposited thereon. In preferred embodiments, the surface of the article including the exposed microcavities is oxidized before seasoning. The article includes cookware. Certain preferred embodiments include forming microcavities by ferritic nitrocarburization wherein the article is heated in an atmosphere including ammonia, nitrogen, and carbon-containing gas to a nitriding temperature of between about 800° F. and about 1300° F. for a time of about 0.5 hours to about 10 hours.

Abstract: Disclosed is a hard-drawn spring which exhibits fatigue strength and sag resistance equal or superior to springs produced using an oil-tempered wire. The hard-drawn spring is produced using a steel wire containing 0.5 to 0.7 mass % of C, 1.0 to 1.95 mass % of Si, 0.5 to 1.5 mass % of Mn and 0.5 to 1.5 mass % of Cr, with the balance being Fe and inevitable impurities. In the steel wire, the number of carbides having circle-equivalent diameters of 0.1 ?m or more is 5 particles/100 ?m2 or less.

Abstract: A method for manufacturing a raceway member, in which a hardness of a region to be plastically deformed is controllable in a stable manner and a sufficient rolling contact fatigue life is ensured by making a hardness of a region including a raceway surface sufficiently high, while suppressing increase in the manufacturing cost, includes a steel member preparation step, a heat treatment step, and a finishing step. The heat treatment step includes: a carbonitriding step, in which the steel member is heated to a carbonitriding temperature, which is a temperature not lower than A1 point, and carbonitrided; a temperature holding step, in which the steel member is cooled from the carbonitriding temperature to a temperature range between not lower than a temperature 100° C.

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).