Abstract: A method of forming a bearing ring having improved hardness is disclosed herein. The method generally includes a duplex hardening process in which the bearing ring is first subjected to a heat treatment. After the heat treatment process, the bearing ring undergoes a nitriding treatment in predetermined portions, including at least a raceway and a cage pilot surface.

Abstract: An ultra-high strength, high toughness alloy steel comprising, by weight, 0.24% to 0.32% carbon, 1.0% manganese or less, 0.45% silicon or less, 1.60% to 1.85% chromium, 2.5% to 3.1% nickel, 0.40% to 0.65% molybdenum, and 0.025% to 0.05% vanadium, the balance being iron and unavoidable impurities; or 0.23% to 0.28% carbon, 1.0% manganese or less, 0.45% silicon or less, 2.05% to 2.4% chromium, 0.35% or less nickel, 0.85% to 1.15% molybdenum, and 0.03% or less vanadium, the balance being iron and unavoidable impurities; or 0.27% to 0.32% carbon, 1.0% manganese or less, 0.45% silicon or less, 0.7% to 1.0% chromium, 0.7% to 1.0% nickel, 0.7% to 1.0% molybdenum, 0.05% or less vanadium, and 0.05% or less niobium, the balance being iron and unavoidable impurities.

Abstract: A workpiece for a fuel injection component is made of a steel having compositions, by mass %, of C: 0.08 to 0.16%, Si: 0.10 to 0.30%, Mn: 1.00 to 2.00%, S: 0.005 to 0.030%, Cu: 0.01 to 0.30%, Ni: 0.40 to 1.50%, Cr: 0.50 to 1.50%, Mo: 0.30 to 0.70%, V: 0.10 to 0.40%, s-Al: 0.001 to 0.100%, and Fe and unavoidable impurities as remaining components. After heating the workpiece to a temperature of 950° C. or more and 1350° C. or less, the workpiece is subjected to a hot forging, and thereafter cooled at an average cooling rate of 0.1° C./sec. or more in a temperature range from 800° C. to 500° C., and at the average cooling rate of 0.02° C./sec. or more and 10° C./sec. or less in the subsequent temperature range from 500° C. to 300° C. to set an area ratio of a bainite structure after hot forging to 85% or more.

Abstract: There is provided a toroidal continuously variable transmission including an input side disk and an output side disk which are provided to be concentric with each other and rotatable in a state where inner side surfaces thereof face each other, and a power roller which is interposed between the input side disk and the output side disk. At least one of the input side disk and the output side disk is configured as a gear disk which has teeth on an outer circumferential portion thereof. Each tooth on the outer circumferential portion of the gear disk is provided with a protruding portion which outwardly protrudes in a radial direction of the gear disk and has a width narrower than a width of the teeth in an axial direction of the gear disk. A tip end surface of the protruding portion serves as a processing reference of the gear disk.

Abstract: A method for production of a track bushing for an undercarriage assembly is provided. The method includes carburizing a base material of the track bushing in less than 100 minutes and to a depth of less than 1000 microns. The base material is medium carbon steel. The method includes hardening the base material. The method includes tempering the base material.

Abstract: A method of manufacturing a sliding camshaft for an internal combustion engine includes providing the sliding camshaft from a steel alloy having a carbon content between 0.25% and 0.60%. The sliding camshaft is then processed with a carbon infusing heat treatment process, such as carburization or carbonitriding. After the sliding camshaft has been processed with the carbon infusing heat treatment process, the sliding camshaft is then processed with a quenching heat treatment process, such as a mar-quenching heat treatment process.

Abstract: A bearing steel composition contains 0.1 to 0.2 wt % C, 3.25 to 4.25 wt % Cr, 9.5 to 11.5 wt % Mo, 5.75 to 6.75 wt % W, 1.5 to 2.5 wt % V, and 2.5 to 3.5 wt % Ni. A bearing component, such as a rolling element, an inner race or outer race, is formed from the bearing steel composition, for example, by a powder metallurgical technique and then is subjected to a case hardening treatment. The bearing component may have a microstructure composed of martensite, retained austenite and at least one of carbides and/or carbonitrides. The carbon level at the surface of the bearing component may be 0.5 to 1.1 wt %.

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: On the contact surface of the rolling bearing part made of alloy steel containing appropriate amounts of Cr and Mo, the C+N content is 0.9 to 1.4 mass % and the area ratio of carbide is 10% or less. At the depth of 1% of the diameter of the rolling element from the contact surface, the hardness is 720 to 832 in Hv, the amount of retained austenite is 20 to 45 volume %, and the compressive residual stress is 50 to 300 Mpa. At the depth of 1 to 3% of the diameter of the rolling element from the contact surface, the average value of the prior austenite grain size is 20 ?m or less and the maximum value of the prior austenite grain size is 3 times or less the average value, and the hardness of the core portion is 400 to 550 in Hv.

Abstract: A method for producing a steel component by performing the treatments of the following sequentially steps 1 and 2 to a steel material containing, by mass %, C: 0.15 to 0.25%, Si: 0.01 to 0.10%, Mn: 0.50 to 0.80%, S: 0.003 to 0.030%, Cr: 0.80 to 1.20%, Mo: 0.30 to 0.45%, Al: 0.015 to 0.050%, and N: 0.010 to 0.025%, wherein Cr/Mn is 1.3 to 2.4, the balance being Fe and impurities, and contents of P and O among the impurities are P: not more than 0.010%, and O: not more than 0.0020%: step 1: a treatment which holds the steel material at a temperature of 850 to 1000° C. in a carburizing atmosphere or carbonitriding atmosphere, and step 2: a treatment which quenches the carburized or carbonitrided steel material, by using quenching oil having a temperature of 40 to 80° C. and a kinetic viscosity of 20 to 25 mm2/s at 40° C.

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: The invention relates to a screw having a head, an adjoining retaining section and a functional tip for use as a self-tapping screw. The functional tip is of greater hardness than the retaining section. The entire screw is made of hardened low-alloy carbon steel.

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: 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 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 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 for processing a low manganese steel is more cost effective and improves residual stress, bending fatigue, and surface characteristics for driveline components. The low manganese steel comprises in combination, by weight, about 0.30-0.75% carbon (C) and 0.15-0.40% manganese (Mn), with the balance being essentially iron (Fe). The method for processing the low manganese steel includes carbonitriding the low manganese steel at temperatures between 1600° F. to 1750° F. for a time period of about three to six hours. The low manganese steel is subsequently quenched in a water based solution that is kept at room temperature. The process provides the low manganese steel with an irregular case profile with a core hardness of no more than 50 Rockwell C and a surface hardness of approximately 58-63 Rockwell C. Further, the process provides the low manganese steel with little or no intergranular oxidation or surface high temperature transformation product.

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 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 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 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: A production method of a rolling/sliding part which includes applying a spherodizing annealing treatment to a steel to render an average particle diameter of the carbide of the surface layer portion in a range of 0.3 to 0.6 ?m and a maximum particle diameter thereof 4 ?m, to render the surface hardness 62 or more by Rockwell C hardness and to render a solid solution carbon amount in a residual austenite of the surface layer portion in a range of 0.95 to 1.15% by weight.

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 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: An articulated structural part includes a peripheral zone. The peripheral zone includes a surface, an outermost layer situated immediately adjacent the surface, a further layer situated adjacent the outermost layer and a core situated adjacent the further layer, wherein the outermost layer is substantially martensite. The further layer includes a varying mixture of martensite and of ferrite or perlite. The core is substantially ferrite or perlite. A process for producing an articulated structural part is also provided.

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: A method of manufacturing a sheave member for a belt-type continuously variable transmission includes a forming step wherein an intermediate product having a sheave surface is formed by forging a steel material; a carburization step wherein the intermediate product is heated in a carburization gas; a gradual cooling step wherein the cooling speed is equal to or less than 20° C./sec, at least until the temperature of the intermediate product has passed through the transformation point; a high-frequency electrical heating step wherein a selected portion(s) of the intermediate product is heated; a water quenching step wherein the selected portion is quenched by contact with water; and a finishing step wherein a grinding process is applied to the intermediate product to attain the final shape. In the cooling step, preferably, the intermediate product is contacted with a cooling gas at a pressure lower than atmospheric pressure.

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: High toughness, high strength alloys are thermochemically processed by performing concurrent bulk alloy heat treatment and surface engineering processing. The concurrent steps can include high temperature solutionizing together with carburizing and tempering together with nitriding.

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: This invention provides a process for producing a high-concentration carburized steel which can realize dispersion of a large amount of fine and spherical carbides without causing lowered service life of a furnace, deformed steel products, and lowered working efficiency. The production process comprises (i) a primary carburization step for carburizing a steel product having a predetermined composition at a primary carburization temperature (T1) (° C.) until the surface carbon concentration (C) reaches a predetermined carbon concentration, (ii) a cooling step of, after the completion of the primary carburization step, cooling the steel product at a cooling rate of not less than 1° C./min to Ar1 point or less, (iii) a secondary carburization initial step of raising the temperature of the steel product to a secondary carburization start temperature (T2s), which is at least 100° C.

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: The invention relates to a gas quenching method of the type that makes use of (i) a quenching cell (V1) which is intended to receive objects to be quenched with a quenching gas and (ii) a buffer capacity (V2) which is designed to contain the quenching gas.

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: A process for heat treating metal workpieces contains with respect to an efficient process control the following successive operations following directly one after the other: a heating phase; an enrichment phase; a first cooling phase; a bonding phase; a second cooling phase; and a concluding quenching phase. Workpieces processed by a method of this type are distinguished by a comparatively great fatigue limit and fatigue strength with simultaneous high resistance to wear and tear.

Abstract: The present invention provides a carburizing method that involves heating a steel component quickly to a relatively high carburizing temperature (e.g. 1900 degrees F. and above), contacting the component at the relatively high carburizing temperature with a methane-containing carburization atmosphere for time to form a carbon-enriched surface case on the component, and cooling the component at a relatively slow rate effective to provide a relatively soft martensite-free surface case on the component. The component then is subjected to a hardening treatment wherein the carburized component is heated to a hardening temperature in the austenitic range followed by quenching and tempering to form a tempered martensitic surface case on an underlying non-martenistic core.

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.

Abstract: A welding structural steel product exhibiting a superior heat affected zone toughness, comprising, in terms of percent by weight, 0.03 to 0.17% C, 0.01 to 0.5% Si, 0.4 to 2.0% Mn, 0.005 to 0.2% Ti, 0.0005 to 0.1% Al, 0.008 to 0.030% N, 0.0003 to 0.01% B, 0.001 to 0.2% W, at most 0.03% P, at most 0.03% S, at most 0.005% O, and balance Fe and incidental impurities while satisfying conditions of 1.2?Ti/N?2.5, 10?N/B?40, 2.5?Al/N?7, and 6.5?(Ti+2Al+4B)/N?14, and having a microstructure essentially consisting of a complex structure of ferrite and pearlite having a grain size of 20 ?m or less. The method includes the steps of preparing a slab of the above-described composition, heating the slab to 1,100° C. to 1,250° C. for 60-180 minutes, hot rolling the heated slab in an austenite recrystallization range at a 40% or more rolling reduction followed by controlled cooling.

Abstract: Low carbon carburizing (surface hardening) and higher carbon through hardening steels primarily containing molybdenum, vanadium and nickel and, to a lesser amount, chromium used for rolling contact bearings, gears and other similar applications where high hardness at elevated temperatures is required. The alloy steel includes, in % by weight: 0.05% to 1.25% C; up to 1.25% Cr; 0.40% to 4% Mn; up to 4.0% Mo; up to 2.0% V; 1.0% to 3.0% Ni; 4% to 8% (Mo+V+Ni+Cr); less than 0.20% Si; and balance Fe plus incidental additions and impurities. The method for providing a steel having improved hardness at elevated temperatures includes the steps of: (a) providing an alloy including, in % by weight: less than 1.25% Cr, 0.4% to 4% Mn, up to 4% Mo, up to 2% V, 1 to 3% Ni, 4% to 8% (Mo+V+Ni+Cr), less than 0.2% Si, a C content selected from one of 0.05% to 0.40% C defining a carburizing steel or greater than 0.40% to 1.

Abstract: High toughness, high strength alloys are thermochemically processed by performing concurrent bulk alloy heat treatment and surface engineering processing. The concurrent steps can include high temperature solutionizing together with carburizing and tempering together with nitriding.

Abstract: A roller member comprising high carbon chromium bearing steel having a carburization treatment. The bearing steel comprising a surface portion defined as a range between a surface of a rolling face of the roller member to a depth where a maximum shearing stress acts thereon, the surface portion containing carbon in a total amount comprising a range of 1.0 to 1.6 wt % and an amount of residual austenite comprising a range of 20 vol % to 35 vol % wherein a compression residual stress of the surface portion comprises a range of 150 to 1000 MPa, wherein a surface hardness of the surface portion comprises a range of 64 or higher in Rockwell C hardness, wherein an amount of carbide precipitate on the surface portion comprises a range of 10% to 25% in an area rate and each carbide particle size comprises a range of 3 ?m or less.

Abstract: A rocker arm 1 made of sheet metal is formed so that Vickers hardness Hv of the surface layer portion 9a of the valve stem receiver 9 is set at Hv 650 to 800 and a quantity of the retained austenite ?R is set at 25 to 35 vol %.

Abstract: An article and method for forming an article having a hard-finished surface including a predetermined density of carbides to improve pitting and wear resistance and to significantly increase the overall life of the article. This method comprises selecting a carburizing grade material to form an article, carburizing the article to form a microstructure on at least one portion of the article having a predetermined density of carbides dispersed in the microstructure to a predetermined depth, quenching the article to form a hardened matrix dispersed with carbides and hard finishing the article to form the surface, the surface having at least approximately 20% by volume fraction carbides dispersed in the hardened matrix.

Abstract: A rolling support device excellent in both of the characteristics of durability and corrosion resistance is provided. The inner ring (1) and the outer ring (2) comprises an austenitic stainless steel and has, on a raceway surface, a carburizing hardened layer containing no substantial carbides at a Vickers hardness (Hv) of 650 or more. The carburizing hardened layer is formed by applying fluoriding and then applying carburizing at a temperature of 540° C. or lower. The rolling element (3) is made of Si3N4.

Abstract: In a first process of a method of gas carburizing, a steel treatment object in a carburizing atmosphere containing carburizing gas is heated to an initial set temperature which is not higher than a peritectic point at which ? iron and a liquid phase transform into ? iron and not less than a eutectic point at which the liquid phase transforms into ? iron and cementite, such that the surface carbon concentration thereof does not exceed a solid solubility limit. In a second process following the first process, the carburizing temperature is gradually decreased from the initial set temperature such that the surface carbon concentration of the treatment object increases without exceeding the solid solubility limit, and such that the carburized depth of the treatment object increases.

Abstract: The invention relates to components made of steel, more particularly outer joint parts and inner joint parts of constant velocity joints, and to a process of heat treating such components made of steel. The heat treatment operation includes the process stages of nitriding, induction surface layer hardening and tempering, which processes follow one another. As a result of the nitriding operation, the joint parts are provided with a surface layer (15) including nitrides and a diffusion layer (18) positioned thereunderneath. The subsequent induction hardening process causes the diffusion layer (18) to be hardened, so that it comprises good supporting characteristics for supporting the surface layer (15) positioned above same.

Abstract: The present invention is directed to a process for producing pearlite from an iron containing article comprising the steps of, (a) heating an iron containing article comprising at least 50 wt % iron for a time and at a temperature sufficient to convert at least a portion of said iron from a ferritic structure to an austenitic structure, (b) exposing said austenitic structure, for a time sufficient and at a temperature of about 727 to about 900° C., to a carbon supersaturated environment to diffuse carbon into said austenitic structure and (c) cooling said iron containing article to form a continuous pearlite structure.

Abstract: A rolling element for a continuously variable transmission, including a plurality of rolling members having rolling contact portions that come into rolling contact with each other via lubricating oil. At least one of the rolling contact portions includes an outer surface layer having a surface microhardness of not less than Hv 750, a surface residual compressive stress of not less than 1000 MPa and a residual austenite content of not more than 10% by volume.

Abstract: Disclosed is a process for producing a retainer for a constant velocity joint for automobiles or the like, which has improved flexural strength properties without sacrificing the machinability, using a steel corresponding to SCr 415 (JIS) or SCM 415 (JIS). This production process comprises the steps of: providing a steel comprising by weight carbon (C): 0.10 to 0.25%, silicon (Si): 0.03 to 0.15%, manganese (Mn): 0.20 to 0.60%, sulfur (S): 0.003 to 0.030%, chromium (Cr): 1.00 to 1.50%, titanium (Ti): 0.05 to 0.20%, boron (B): 0.0005 to 0.0050%, and nitrogen (N): not more than 0.01% with the balance consisting of iron (Fe) and inevitable impurities; hot forging the steel at a heating temperature of 1000 to 1100° C. to prepare a forged product having a Rockwell hardness of not more than 88 HRB; machining and optionally piercing the forged product; carburizing and quenching and tempering the machined steel to attain an effective case depth of 0.4 to 0.

Abstract: A method of improving wear-resistance and anti-seizing properties of slide surface of machineries, such as outer slide surfaces of piston pins of vehicle engines, wherein slide surfaces of iron or steel base materials of machineries are first processed carburizing, then the carburized surfaces are plated with chromium, and next the chromium-plated surfaces undergo impulses fine peening to produce lubricant-retaining cavities on the slide surfaces, which include fine cavities in the form of depressions in the chromium-plating layer and relatively large cavities produced by exfoliation of the chromium-plating layer.