Abstract: The present invention provides a steel product for gas carburizing used for manufacturing a carburized steel part. In the above steel product for gas carburizing, a composition of a base metal contains, in mass %, C: 0.1 to 0.4%, Si: exceeding 1.2 to 4.0%, Mn: 0.2 to 3.0%, Cr: 0.5 to 5.0%, Al: 0.005 to 0.1%, S: 0.001 to 0.3%, N: 0.003 to 0.03%, and O: limited to 0.0050% or less, and P: limited to 0.025% or less, and when the contents of Si, Mn, and Cr (mass %) are set to [Si %], [Mn %], and [Cr %], Expression (1) below is satisfied, and an alloy shortage layer satisfying Expression (2) below exists in a range from its surface to 2 to 50 ?m in depth. 32?3.5[Si %]+[Mn %]+3[Cr %]>9??(1) 3.

Abstract: A method of processing steel includes carburizing a martensitic stainless steel work piece to produce a carburized case by utilizing in combination, (i) a composition of the martensitic stainless steel work piece, (ii) a preselected carbon concentration in the carburized case, and (iii) a preselected grain size of the martensitic stainless steel work piece such that the carburized case predominately forms carbides of composition M6C, M2C, M23C6 or combinations thereof. The martensitic stainless steel work piece is then heated to substantially solution the metal carbides. The work piece is then quenched at a cooling rate that is sufficient to avoid substantial precipitation of any carbides during cool down to the martensite start temperature, then given a low temperature temper. In so doing, the carburized case hardened martensitic stainless steel will have balanced mechanical, tribological and corrosion resistance properties for high performance bearing and gear components.

Abstract: A manufacturing method for a composite steel part including manufacturing a first steel part by preparing an intermediate product in which an extra portion is added, and heating the intermediate product to an austenitizing temperature in a carburizing atmosphere to form a carburized layer, cooling the intermediate product at a rate less than a cooling rate at which martensitic transformation is caused and in which the intermediate product is cooled to a temperature equal to or less than a temperature at which structure transformation due to the cooling is completed, heating the intermediate product to an austenitizing range by high-density energy and thereafter cooled at a rate equal to or more than the cooling rate at which martensitic transformation is caused to form a carburized quenched portion, cutting the extra portion of the intermediate product, and welding the first steel part and the second steel part to each other.

Abstract: A carburizing process for increasing the hardness of a case region of a steel component. In one form the application includes plating the outer surface of a stainless steel component with nickel prior to carburizing. One component includes a stainless steel object having a hardened case substantially free of continuous phase grain boundary carbides.

Abstract: A carburized steel member is manufactured by specific carburizing, cooling, and quenching steps. The steel member contains: C: 0.1% to 0.4%, Si: 0.35% to 3.0%, Mn: 0.1% to 3.0%, P: 0.03% or less, S: 0.15% or less, Al: 0.05% or less, and N: 0.03% or less, and a content of Cr is less than 0.2%, a content of Mo is 0.1% or less, and remainder is constituted of Fe and unavoidable impurities. A surface layer thereof includes: a first layer having a carbon concentration of 0.60 mass % to 0.85 mass % and including a martensitic structure in which no grain boundary oxide layer caused by Si exists; a second layer having a carbon concentration of 0.1 mass % to 0.4 mass % and including a martensitic structure; and a third layer having a carbon concentration of 0.1 mass % to 0.4 mass % and including no martensitic structure.

Abstract: To provide an iron-based composite material which has higher abrasion and seizure resistance, and more excellent impact absorbing property as compared with a steel material, and which has higher mechanical strength as compared with a cast iron material, and also a method of manufacturing the iron-based composite material. The iron-based composite material includes at least a steel structure layer 12, a cast iron structure layer 14, and a carburized structure layer 13 which is formed by carburizing the steel structure between the steel structure layer 12 and the cast iron structure layer 14.

Abstract: Disclosed is a steel for machine structural use including 0.05-0.8% of C, 0.03-2% of Si, 0.2-1.8% of Mn, 0.1-0.5% of Al, 0.0005-0.008% of B, and 0.002-0.015% of N, and including 0.03% of P or less (excluding 0%), 0.03% of S or less (excluding 0%), and 0.002% of 0 or less (excluding 0%), with the remainder comprising iron and unavoidable impurities. The ratio of BN/A1N precipitated in the steel is 0.020-0.2. Also disclosed is a case hardened steel component in which the ratio of BN/AlN deposited on the carburized or carbonitrided component surface is 0.01 or less and a manufacturing method for same. The steel for machine structural use exhibits excellent machinability in continuous cutting at high speeds using cemented carbide tools, and in interrupted cutting at low speeds using high-speed steel tools, as well as excellent impact performance, even after being subjected to a heat treatment such as quenching and tempering.

Abstract: Disclosed is a carburization heat treatment method including carburizing a workpiece at a relatively low temperature within a temperature range of A1˜A3 using a vacuum carburizing furnace and then performing quenching using a high-pressure gas, in which the workpiece is made of typical carburizing alloy steel having a carbon content of about 0.10˜0.35 wt %. This method can be applied to carburization heat treatment of a steel workpiece sensitive to heat deformation, such as an annulus gear, in lieu of a conventional gas carburization method using plug quenching.

Abstract: A process for the high temperature carburization of steel comprising heating said steel in a vacuum furnace in the presence of a hydrocarbon carburizing gas in combination with hydrogen wherein said carburizing gas/hydrogen combination is administered to the vacuum furnace by cyclically reducing the pressure in the furnace followed by the pulsed addition of the hydrocarbon carburizing gas with hydrogen at partial pressure followed by a second diffusion cycle wherein the steel is further annealed for a time sufficient to allow for the additional deposition of from about 0.8% to about 3.0% m/o of said carbon onto the surface of said steel to permit the further migration of the carbon from the steel surface to the interior thereof.

Abstract: An advanced secondary hardening carburized Ni—Co steel achieves an improved case hardness of about 68-69 Rc together with nominal core hardness of about 50 Rc.

Abstract: Disclosed is a carburization heat treatment method including carburizing a workpiece at a relatively low temperature within a temperature range of A1˜A3 using a vacuum carburizing furnace and then performing quenching using a high-pressure gas, in which the workpiece is made of typical carburizing alloy steel having a carbon content of about 0.10˜0.35 wt %. This method can be applied to carburization heat treatment of a steel workpiece sensitive to heat deformation, such as an annulus gear, in lieu of a conventional gas carburization method using plug quenching.

Abstract: A carburized steel part having excellent low cycle bending fatigue strength which is comprised of a steel material which contains, by mass %, C: 0.1 to 0.6%, Si: 0.01 to 1.5%, Mn: 0.3 to 2.0, P: 0.02% or less, S: 0.001 to 0.15%, N: 0.001 to 0.03%, Al: 0.001 to 0.06%, and O: 0.005% or less and has a balance of substantially iron and unavoidable impurities and which is carburized and quenched, and then tempered, which steel part has a surface hardness of HV550 to HV800 and a core hardness of HV400 to HV500.

Abstract: A method for manufacturing a carburized part that includes vacuum carburizing a steel under a reduced pressure of 2 kPa or less, so that a surface carbon concentration after slow cooling performed after carburizing falls in a range of 0.9 to 1.5%, performing the slow cooling by air cooling at such a cooling rate that causes pearlite transformation, to transform a surface structure into pearlite; and thereafter, performing induction hardening under such heating and cooling conditions that produce fine carbides in a range of up to 0.1 mm from a surface by finely dividing cementite in the pearlite structure, where the fine carbides contain 90% or more of carbides of 1 ?m or less.

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: The present invention is directed to a process for tempering steel comprising carburizing said steel in a vacuum furnace in the presence of a hydrocarbon carburizing gas in combination with hydrogen wherein said carburizing gas/hydrogen combination is administered to the vacuum furnace by cyclically reducing the pressure in the furnace followed by the pulsed addition of the hydrocarbon carburizing gas consisting of an acetylene/hydrogen mixture is in a ratio of from about 1:1 to about 1:10 to replenish the air removed in the pressure reduction step.

Abstract: A method of heat-treating a steel member including carburizing a steel member in a carburizing gas under a reduced pressure. The steel member is then cooled in a cooling gas having a pressure lower than atmospheric pressure. A desired portion of the cooled steel member is then heated using high-density energy. The steel member is then quenched.

Abstract: One exemplary embodiment includes a process for forming a hard carbide coating onto a low chromium-containing steel article via a chemical deposition process carried out on a particulate mix, in which molybdenum in the form of a compound FeMo or titanium in the form of a compound FeTi, or a mixture of FeMo and FeTi, may be added to the particulate mix used to form the coating.

Abstract: This case hardening steel has a chemical composition including, by mass %: C: 0.1 to 0.6%; Si: 0.02 to 1.5%; Mn: 0.3 to 1.8%; P: 0.025% or less; S: 0.001 to 0.15%; Al: over 0.05 to 1.0%; Ti: 0.05 to 0.2%; N: 0.01% or less; and O: 0.0025% or less, and further including, by mass %, one or more of Cr: 0.4 to 2.0%, Mo: 0.02 to 1.5%, Ni: 0.1 to 3.5%, V: 0.02 to 0.5%, and B: 0.0002 to 0.005%, and the balance consisting of iron and unavoidable impurities.

Abstract: A carburized component with a base metal containing 0.10% to 0.40% C, 0.05% to 0.8% Si, 0.35% to 1.2% Mn, 2.0% to 5.0% Cr, remnant including Fe and inevitable impurities, a carburized layer formed on a surface layer portion, a grain boundary oxidized layer depth of 1 ?m or less on a surface thereof and an average C concentration of 1.5% to 4.0% at 25 ?m deep from the surface, and adjusted so as to satisfy 1.76 SC?1.06<WCr<1.76 SC+0.94, wherein said carburized layer also has a carbide area ratio of 15% to 60% at 25 ?m deep from the surface, a fine carbide area ratio, a dimension of 0.5 ?m to 10 ?m, and constitutes 80% or more of the total and 70% by volume or more of said fine carbide is M3C type.

Abstract: The present invention provides a carburized steel part obtained by subjecting a base material to a cutting operation and a carburizing operation, in which the base material includes chemical components of: C: greater than 0.3 but less than or equal to 0.6% by mass; Si: 0.01 to 1.5% by mass; Mn: 0.3 to 2.0% by mass; P: 0.0001 to 0.02% by mass; S: 0.001 to 0.15% by mass; N: 0.001 to 0.03% by mass; Al: greater than 0.06 but less than or equal to 0.3% by mass; and, 0: 0.0001 to 0.005% by mass, with a balance including iron and inevitable impurities, and in which the carburized steel part has a hardness of HV550 to HV800 in a surface layer portion, and a hardness of HV400 to HV550 in a core portion.

Abstract: A compression molding which is high in both dimensional accuracy and mechanical strength is difficult to manufacture by a powder molding process. Especially, a molding including a soft magnetic material with high soft magnetic properties is difficult to manufacture. A composite metal molding according to the present invention includes metal particles and the carbide of a resin intervening among the particles. It is manufactured by coating metal particles with a resin, molding the prepared molding material under pressure into a predetermined shape, and heating the prepared pressurized preform to calcine the resin and weld mutually the particles. The carbide of the resin has a weight ratio of 0.001 to 2% to the metal particles when the particles have their proportion expressed as 100. The particles have a weld ratio of 10 to 80%. The particles preferably contain a soft magnetic material and the resin is preferably a furan resin.

Abstract: The invention relates to a method for producing a cylinder jacket, comprising the following steps: producing a cylindrical starting product from a steel material having a carbon content of not more than 0.8% by weight and a ferritic or ferritic/pearlitic structure; enriching, by carburization, the surface layer of the inner peripheral surface of the cylindrical starting product with carbon in the form of carbides that are deposited on the grain boundaries; slowly cooling the cylindrical starting product in such a manner that a pearlitic structure having a carbide network is formed in the surface layer; finishing the cylindrical starting product to give a cylinder jacket. The invention also relates to a cylinder jacket produced by said method.

Abstract: Iron-carbon-manganese austenitic steel sheet, the chemical composition of which comprises, the contents being expressed by weight: 0.45%?C?0.75%; 15%?Mn?26%; Si?3%; Al?0.050%; S?0.030%; P?0.080%; N?0.1%; at least one metal element chosen from vanadium, titanium, niobium, chromium and molybdenum, where 0.050%?V?0.50%; 0.040%?Ti?0.50; 0.070%?Nb?0.50%; 0.070%?Cr?2%; 0.14%?Mo?2%; and, optionally, one or more elements chosen from 0.0005%?B?0.003%; Ni?1%; Cu?5%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the amounts of said at least one metal element in the form of precipitated carbides, nitrides or carbonitrides being: 0.030%?Vp?0.150%; 0.030%?Tip?0.130%; 0.040%?Nbp?0.220%; 0.070%?Crp?0.6%; 0.14%?Mop?0.44%.

Abstract: An advanced secondary hardening carburized Ni—Co steel achieves an improved case hardness of about 68-69 Rc together with nominal core hardness of about 50 Rc.

Abstract: A wear component includes a base metal and a carburized case on the base metal. The carburized case may have a first region having greater than or equal to about 75% volume fraction of carbides and a second region having greater than or equal to about 20% volume fraction of carbides. The first region may be a region extending to a depth greater than or equal to about 5 microns from a surface of the wear component, and the second region may be a region below the first region and having a thickness greater than or equal to about 100 microns.

Abstract: The invention provides a deep groove ball bearing which exhibits a long life even in a high-temperature environment or an environment involving the penetration of water in spite of its low alloying element content. The outer race, inner race and ball constituting the bearing are made of a steel which contains 0.3 to 0.4% of carbon, 0.3 to 0.7% of silicon, 0.3 to 0.8% of manganese, 0.5 to 1.2% of nickel, 1.6 to 2.5% of chromium, 0.1 to 0.7% of molybdenum and 0.2 to 0.4 of vanadium with the balance consisting of iron and impurities and in a total content of silicon and manganese of 1.0% or below, a total content of nickel and chromium of 2.3% or above and a total content of chromium, molybdenum and vanadium of 3.0% or below.

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: A chain pin manufacturing method that requires only one heat treatment step of forming a boundary part composed of (V, Cr) 8C7 by Cr and C in a base material at first through a cementation process in a VCl atmosphere by using Cr-rich steel as the pin base material and of forming a surface layer composed of V8C7. A Cr content in the boundary part decreases gradually toward the base material and the surface layer and the boundary part is not clearly divided. The inventive manufacturing method is simple and enables to manufacture the pin having high abrasion resistance and suitably used in a severe environment like a timing chain.

Abstract: A method for manufacturing a carburized part that includes vacuum carburizing a steel under a reduced pressure of 2 kPa or less, so that a surface carbon concentration after slow cooling performed after carburizing falls in a range of 0.9 to 1.5%, performing the slow cooling by air cooling at such a cooling rate that causes pearlite transformation, to transform a surface structure into pearlite; and thereafter, performing induction hardening under such heating and cooling conditions that produce fine carbides in a range of up to 0.1 mm from a surface by finely dividing cementite in the pearlite structure, where the fine carbides contain 90% or more of carbides of 1 ?m or less.

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: To provide an iron-based composite material which has higher abrasion and seizure resistance, and more excellent impact absorbing property as compared with a steel material, and which has higher mechanical strength as compared with a cast iron material, and also a method of manufacturing the iron-based composite material. The iron-based composite material includes at least a steel structure layer 12, a cast iron structure layer 14, and a carburized structure layer 13 which is formed by carburizing the steel structure between the steel structure layer 12 and the cast iron structure layer 14.

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: The application contemplates a steel body having a hardened case portion and a core portion. The case portion has a hardness of at least Rc 50 and is substantially free of continuous phase grain boundary carbides. The steel body is formed of Pyrowear 675 which is a stainless steel material.

Abstract: Disclosed is a carburization heat treatment method including carburizing a workpiece at a relatively low temperature within a temperature range of A1˜A3 using a vacuum carburizing furnace and then performing quenching using a high-pressure gas, in which the workpiece is made of typical carburizing alloy steel having a carbon content of about 0.10˜0.35 wt %. This method can be applied to carburization heat treatment of a steel workpiece sensitive to heat deformation, such as an annulus gear, in lieu of a conventional gas carburization method using plug quenching.

Abstract: A steel component formed by carburizing and then induction-hardening of a steel consisting essentially of, by mass, C: minimum 0.08% and less than 0.3%; Si: maximum 2.0%; Mn: from 0.2% to 3.0%; P: maximum 0.03%; S: from 0.005% to 0.05%; Ni: maximum 1.5%; Cr: maximum 3.0%; Mo: maximum 1.0%; O: maximum 0.0025%; and N: from 0.005% to 0.03%; and further including either or both of, by mass, Al: from 0.005% to 0.05%, and Ti: from 0.005% to 0.05%; and still further including either or both of, by mass, V: maximum 0.3%, and Nb: maximum 0.3%; and a balance including Fe and unavoidable impurities. The hardness of the surface layer is at least 55 HRC and the hardness of the core portion is from 20 to 50 HRC. The core portion does not include a martensite structure.

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: 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 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: Various inexpensive rolling elements for use under high interface pressure such as induction hardened gears are provided, which have improved seizure resistance at tooth flanks and a temper hardness of HRC 50 or more at 300° C. To this end, a rolling element is made from a steel material which contains at least 0.5 to 1.5 wt % carbon and 0.2 to 2.0 wt % one or more alloy elements selected from V, Ti, Zr, Nb, Ta and Hf; and in which 0.4 to 4.0% by volume one or more compounds selected from the carbides, nitrides and carbonitrides of the above alloy elements and having an average particle diameter of 0.2 to 5 ?m are dispersed. In such a rolling element, the soluble carbon concentration of a martensite parent phase of a rolling contact surface layer is adjusted to 0.3 to 0.8 wt %, the martensite parent phase having been subjected to induction hardening and low temperature tempering, and one or more of the above carbides, nitrides and carbonitrides are dispersed in an amount of 0.4 to 4.

Abstract: A metal material that is, without using expensive apparatus, carburized in a low temperature region where crystal grains do not grow so much, and a producing method of the metal material are provided. A metal material mainly containing iron, wherein a surface of the metal material is subjected to a carburization treatment by a treatment using fullerenes as a carbon source.

Abstract: An iron-base sintered part having high density and totally enhanced strength, toughness and abrasion resistance, a manufacturing method of the iron-base sintered part, and an actuator are disclosed. The iron-base sintered part is formed by an iron-nickel-molybdenum-carbon-based sintered alloy, has density of 7.25 g/cm3 or more, and has a carburization quenched structure. A method for manufacturing the iron-base sintered part includes a molding process of charging a raw mixture powder of an iron-nickel-molybdenum-based metal powder and a carbon-based powder into a cavity of a molding die and compressing the raw powder in the cavity to form a consolidation body, a sintering process of sintering the consolidation body at a sintering temperature to form a sintered alloy, and a carburization quenching process of heating the sintered alloy in a carburization atmosphere and quenching the heated alloy.

Abstract: A workpiece is designed for rolling stresses and includes a body having a core zone and a carbonitrided surface zone which surrounds the core zone. The workpiece body is formed of a fully hardening steel. The core zone has a bainite microstructure as its main constituent. The surface zone of the workpiece has a mixed microstructure comprising martensite and bainite and the martensite in the surface zone constitutes a proportion of at least twenty percent by volume.

Abstract: An alloy composition forms a steel having low manganese content, low silicon content, and medium carbon content. The alloy composition comprises in combination, by weight, about 0.3 to 0.5% carbon (C) and 0.15 to 0.40% manganese (Mn), with the balance being essentially iron (Fe). Further, the alloy composition has no more than about 0.04% aluminum (Al), no more than about 0.035% phosphorous (P), no more than about 0.025% sulfur (S), no more than about 0.15% chromium (Cr), no more than about 0.18% silicon (Si), and no more than about 0.08% molybdenum (Mo). The use of an alloy composition with lower silicon and manganese contents eliminates the need for prolonged carbuization. Instead, shorter carbonitriding cycles can be used, which results in improved residual stress, bending fatigue, and surface characteristics for driveline components.

Abstract: Link chain with improved wear resistance as well as method of manufacturing such a link chain. For manufacturing of a link chain, several chain links (39; 40) comprising link pins (41) or plates provided with coatings being applied by means of a PVD process are assembled. The coatings consist of hard material layers and/or slide material layers. It is possible that no PVD coating is provided on a transition zone (1a; 4) of elements (41; 42) used for the manufacturing of the chain links predetermined for connection with another element (42; 41).

Abstract: A double carboaustempering combined with a martensite-producing quench provides plain-carbon and low alloy steel power transmission shafts with a carbon-rich exterior having a martensite and bainite microstructure and a substantially bainite interior. The shafts offer increased fatigue resistance.

Abstract: The invention relates to a cold-working steel having a chemical composition, in % by weight, of 1.3-2.4 (C+N), whereof at least 0.5 C, 0.1-1.5 Si, 0.1-1.5 Mn, 4.0-5.5 Cr, 1.5-3.6 (Mo+W/2), but max 0.5 W, 4.8-6.3 (V+Nb/2), but max 2 Nb, and max 0.3 S, in which the content of (C+N) and of (V+Nb/2) are balanced in relation to each other such that the contents of these elements are within an area that is defined by the coordinates A, B, C, D, A in the system of coordinates in FIG. 11, where the coordinates of [(C+N), (V+Nb/2)] for these points are A: [1.38, 4.8], B: [1.78, 4.8], C: [2.32, 6.3], D: [1.92, 6.3], and a balance essentially only iron and impurities at normal contents.

Abstract: A steel part according to the present invention is a part in which a surface of an austenitic stainless steel containing 3 to 20 mass % of Mn was carbonitrided to be hardened. By setting Vickers hardness of the surface to 1350 HV or more and setting a depth of a hardened layer having 1000 HV or more from the surface of the steel to 10 ?m or more, when the part according to the present invention is applied to a part required for sliding and wear resistance particularly, the service life can be improved significantly. Further, since the manufacturing method is performed by only heating in a gas atmosphere, a large number of parts can be simultaneously treated. Thus the stainless steel parts of the present invention can be adopted to wide fields as stainless steel parts required for wear resistance.

Abstract: There is provided an inexpensive rolling element used under high interface pressure such as induction hardened gears, the rolling element being improved in the seizure resistance of its tooth flanks and having a temper hardness of HRC 50 or more at 300° C. To this end, the rolling element is made from a steel material containing at least 0.45 to 1.5 wt % C and one or more alloy elements selected from 0.1 to 0.5 wt % V and 0.3 to 1.5 wt % Cr, and has a rolling contact surface layer having a structure tempered at low temperature in which 2 to 18% by volume cementite disperses in a martensite parent phase formed by induction heating and cooling and containing 0.25 to 0.8 wt % carbon solid-dissolving therein.

Abstract: A fuel injection valve for internal combustion engines, having a valve body and at least one injection opening embodied in it, through which opening, controlled by a valve needle that cooperates with a valve seat embodied in the valve body, fuel can be injected into the combustion chamber of the engine. The valve body comprises a high-alloy hot-work steel, which has been hardened by a case-hardening process.