Abstract: The invention discloses a carburizing steel composition comprising, by weight: 0.06% to 0.18% of C; 0.5% to 1.5% of Si; 0.2% to 1.5% of Cr; 1% to 3.5% of Ni; 1.1% to 3.5% of Mo; and, if appropriate: at most 1.6% of Mn; and/or at most 0.4% of V; and/or at most 2% of Cu; and/or at most 4% of Co; the complement being constituted by iron and residual impurities; the amounts of Ni, Mn, Cu, Co, Cr, Mo and V in said composition, expressed by weight, satisfying the following relationships: 2.5≦Ni+Mn+1.5Cu+0.5Co≦5  (1) 2.4≦Cr+Mo+V≦3.7  (2) and a process for producing carburized and treated parts produced from the compositions.

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: Disclosed is a process for producing an inner race for a constant velocity joint comprising the steps of: providing a steel comprising by weight carbon 0.10 to 0.25%, silicon 0.03 to 0.15%, manganese 0.20 to 0.60%, sulfur 0.003 to 0.030%, chromium 1.00 to 1.50%, titanium 0.05 to 0.20%, boron 0.0005 to 0.0050%, and nitrogen not more than 0.01% with the balance consisting of iron and impurities; hot rolling or hot forging the steel, to prepare a rolled/forged product; cold forging and machining the rolled/forged product; and carburizing, quenching, and tempering the machined rolled/forged product so that the treated steel satisfies an effective case depth of 0.4 to 0.9 mm, a thickness of abnormal-carburizing layer of not more than 15 &mgr;m, and an austenite grain size number as specified in JIS G 0551 of not less than 7.

Abstract: A rolling, sliding part comprises a bearing steel, is subjected to a carburizing treatment and has a surface layer from a surface the part to a depth to which a maximum shear stress acts. The surface layer is 1.0 to 1.6 wt. % in total carbon content, has a matrix containing 0.6 to 1.0 wt. % of solid-solution carbon, and contains a precipitating carbide in an amount of 5 to 20% in area ratio, the carbide being up to 3 &mgr;m in particle size. The rolling or sliding part is improved in wear resistance, usable with a lubricant free of or less susceptible to impression by extraneous matter present in the lubricant, and less susceptible to compressive stress due to the extraneous matter, with the development of cracks suppressed.

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 bearing pressure-resistant member, including a matrix and a carbide dispersed in the matrix, the carbide having an average particle size of not more than 0.3 &mgr;m. A carbon (C) content in an outer surface of the bearing pressure-resistant member is in a range of 0.6 to 1.5 mass percent. A process for making the bearing pressure-resistant member including subjecting a workpiece containing C to either of gas carburizing and gas carbonitriding to enhance the C content in the outer surface of the workpiece to 0.6 to 1.5 mass percent, holding the workpiece at a first temperature not more than an Ac1 transformation point under reduced pressure, heating the workpiece to a second temperature not less than the Ac1 transformation point under reduced pressure, followed by holding the workpiece at the second temperature, and subjecting the workpiece to quenching.

Abstract: Steel alloys susceptible to case and core hardening comprising 0.05 to 0.24 weight percent carbon; 15 to 28 weight percent cobalt and 1.5 to 9.5 weight percent in nickel, small percentages of one or more additives: chromium, molybdenum, and vanadium; and the balance iron.

Abstract: A method for quenching steel parts having undergone a low-pressure thermal processing, which consists of submitting the parts to a high-pressure air flow.

Abstract: High speed steel (HSS) compositions having less C and Cr contents than standard grades of HSS to permit carburization using conventional techniques. The alloys contain less than 0.40 wt. % C and less than 2% Cr. The low Cr content is a critical factor in enhancing the ease of carburizing the present steels. The resulting HSS compositions possess high hardness and fracture resistance. More particularly, the steels include, in % by weight: 0-0.4% C; 0.5-1.5% Cr; 1.5-3.5% Ni; 0.1-0.6% M; 0.15-0.65 % Si; 0.03 max % P; 0.03 max % S; one or more members selected from the group consisting of 4.0-15.3% Mo; 1.0-5.7% V; up to 13% Co and up to 28% W, and wherein the aggregate amount of %Cr+%Mo+%V+%W+%Co is between 7.5-35% and balance essentially Fe and incidental impurities. A method for treating the above alloy includes the steps of carburizing at about 960° C. followed by quenching, preheating to about 870° C. followed by austenitizing at 1125° C.-1225° C.

Abstract: High surface pressure resistant steel parts and their producing methods are disclosed. These steel parts are useful as gears, cams, bearings and similar high-strength compact steel articles which are required to have wear resistance and strength to withstand fatigue in rolling or rolling-slipping applications. In a steel part formed according to the invention, a fine nitride and/or carbonitride having at least an average grain size of 0.3 &mgr;m or less is dispersed in the contact surface structure; a multi phase structure composed of martensite, which is divided into extremely fine pieces, forming a disordered shape, by the nitride and/or carbonitride, is formed; and a carbide having a grain size of 3 &mgr;m or less is dispersed to increase the hardness of the surface.

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: Apparatus and process for recycling a quenching gas, such as helium, to be used with a treating gas, such as a carburizing gas, for the treating of components in an atmospheric furnace.

Abstract: A heat resistant carburized rolling bearing component is formed of a steel material at least containing, as alloy elements in a matrix, by mass %, at least 0.1% and at most 0.4% of C, at least 0.3% and at most 3.0% of Si, at least 0.2% and at most 2.0% of Mn, at most 0.03% of P, at most 0.03% of S, at least 0.3% and less tan 2.5% of Cr, at least 0.1% and less than 2.0% of Ni, at most 0.050% of Al, at most 0.003% of Ti, at most 0.0015% of O and at most 0.025% of N, and a remaining part of Fe and an unavoidable impurity, and the bearing component is prepared by performing carburizing-carbo-nitriding process followed by quenching, and after quenching, tempering at a tempering temperature of at least 200° C. and at most 350° C., and surface hardness after tempering process is at least HRC57.

Abstract: Steel compositions and processes are described that provide optimum resistance to austenite grain coarsening in cold-formed and carburized components for automotive and machine structural applications. The steel compositions include, in weight percent, 0.1-0.3% C 150-220 ppm N and a grain refining addition selected from the group consisting of Al, V plus Al and Nb plus Al, the balance comprising iron and other alloying elements typically found in carburizing grades of steel. The steels are processed by reheating to a temperature in the vicinity of solution temperature of the least soluble species of grain refining precipitate and then hot worked. The hot-worked steel is cooled at an accelerated rate to 500° C. and then subcritically annealed, cold formed in at least one operation with intermediate anneals subcritically annealed after the last cold-forming operation, and carburized quenched and tempered (6).

Abstract: For easily producing a toothed material for high-strength gears etc. with a plastic working technique, deformation resistance occurring in plastic working is reduced and stable high precision plastic working is enabled at lower temperatures. One or more types of heat treatment selected from carburization, carbonitriding and nitriding and a hardening process are applied to an alloy steel material containing: iron as a main component; at least 1.0 to 4.5 wt % Si; 0.35 wt % or less C; and balance Fe and unavoidable impurities, whereby a rolling element is obtained which has a surface layer mainly composed of martensite containing no &agr;-Fe phase and of residual austenite and an inner structure cooled from an (&agr;+&ggr;)-Fe two phase region.

Abstract: In a rolling bearing having a rolling bearing ring and a rolling element of at least 20 mm in diameter, at least one of the rolling bearing ring and the rolling element consists of carburized or carbonitrided steel containing at least 0.2 wt % and not more than 0.35 wt % of carbon and at least 2.2 wt % and not more than 3.6 wt % of Ni. Thus obtained is a rolling bearing capable of reducing the material cost and increasing the fatigue life or reducing the carburizing time by ensuring surface hardness and optimizing the case depth.

Abstract: A pulley useable with a driving belt in a continuously variable transmission, including a moveable pulley half having an integral cylinder portion integrally formed therewith by plastic working. The moveable pulley half includes an axially extending hollow shaft portion, a radially outwardly extending flange portion having a contact surface frictionally contacted with the driving belt, and the integral cylinder portion axially extending at near an outer peripheral portion of the flange portion. The plastic working includes forming a workpiece, machining the workpiece, spinning the workpiece to form the integral cylinder portion, heat-treating the workpiece and finishing the workpiece to complete the moveable pulley half.

Abstract: A carburizing method is described which is capable of dispersing cementite grains in the surface of steel uniformly and finely as not to affect fatigue strength and capable of fining the crystal grains of austenite. To prevent cementite precipitation during high temperature carburization at 980° C. or more, steel contains Al in an amount in the range of 0.05≦[Al wt %]≦2.0 and Cr in an amount in the range of 0.3≦[Cr wt %]≦4.0, and the composition of the steel satisfies the requirement represented by 1.9≧−5.6[Si wt %]−7.2[Al wt %]+1.1[Mn wt %]+2.1[Cr wt %]−0.9[Ni wt %]+1.1[Mo wt %]+0.6[W wt %]+4.3[V wt %].

Abstract: A rolling or sliding part is produced from a blank of steel material subjected to a heat treatment including carburization and thereby made to contain a spheroidal carbide precipitated and dispersed in a carburized layer matrix. The particle-to-particle distance of the spheroidal carbide is up to 15 &mgr;m in terms of the distance between the most proximate particles. The rolling or sliding part is suitable as antifriction bearing components, such bearing rings and rolling bodies, or as sliding bearing components, for use in soiled oil containing extraneous matter. The antifriction bearing comprising this part serves a lengthened rolling life in soiled oil and clean oil, and the sliding bearing incorporating the part is also given an extended life.

Abstract: A method for the production of hollow shafts from welded or seamlessly produced steel tubes having a maximum carbon content of 0.35% includes (1) carburizing a tube to a carbon content greater than 0.5%; (2) slowly cooling the carburized steel tube down from the process temperature, so that it undergoes no increase in hardness; (3) machining and/or non-cutting processing the carburized and soft steel tube to produce a workpiece blank; and (4) hardening the workpiece blank by local heating and quenching at desired points.

Abstract: A method for the heat treatment of steel, comprising carburization hardening said steel, to form carburized steel, followed by a second hardening, reduces the grain size of steel while precipitating carbonitrides inside the grains of steel, thereby increasing the strength of the heat-treated steel. The carburization hardening comprises heating the steel to a first austenitic temperature range in an atmosphere comprising a carburizing gas and optionally ammonia, cooling the steel to a martensitic temperature range, and quenching the steel, and the second hardening comprises heating the carburized steel to a second austenitic temperature range in an atmosphere comprising a carburizing gas and ammonia, and quenching the steel.

Abstract: A steel composition and method of processing have been developed that provide good grain coarsening resistance and optimum toughness after austenitizing at high temperatures for extended periods of time. The composition comprises, in % by weight, about: 0.10-0.40% C, 0.018-0.064% Nb, 0.024-0.066% Al, and 80-220 ppm N, the balance being Fe and other alloying elements found in common carburizing grades of steel. The steel is particularly suited to improving the core toughness of case-carburized components that require through-section toughness and fatigue resistance.

Abstract: A method for forming a pipe includes providing a tubular workpiece having an upper portion and a lower portion; forming a tapered hole in the inner wall of the upper portion of the workpiece and forming an annular shoulder on the outer wall of the upper portion of the workpiece synchronously by cold forging operation; forming a plurality of teeth on the outer wall of the lower portion of the workpiece by a turning-machining operation, thereby forming the pipe which includes the tapered hole, the annular shoulder, and the teeth; and finally reinforcing the pipe by carburizing treatment.

Abstract: A carburizing steel having the following chemical composition:C: 0.1 to 0.25%,Si: 0.2 to 0.4%,Mn: 0.3 to 0.9%,P: 0.02% or less,S: 0.001 to 0.15%,Cr: 0.5 to 0.9%,Mo: 0.15 to 1%,Al: 0.01 to 0.1%,B: 0.0005 to 0.009%,N: less than 0.006%, andthe balance of Fe and incidental impurities, wherein % is on a weight basis. Also disclosed are a method for the manufacture of the carburizing steel, parts of constant velocity universal joints for drive shafts made of the carburizing steel, as well as a method for the manufacture of such parts. The carburizing steel may further contain Ni: 0.3-4.0%, and one or more elements selected from the group consisting of Ti, Nb, V and Zr: 0.01-0.3% for each. The parts of constant velocity universal joints for drive shafts are manufactured using the carburizing steel of the present invention as a material. When they are carburized and quenched, they exhibit a surface hardness (Hv) of 650-800, core hardness (Hv) of 250-450, and carburized case depth of 0.2-1.2 mm.

Abstract: Improved input and output discs for toroidal type continuously variable transmissions are obtained by select processing techniques to form hardened layers. Processing techniques include, e.g., carburizing, carbonitriding, and high-frequency induction hardening. Shot peening may be used to impart compressive residual surface stress to predetermined disc portions to enhance resistance to cracking.

Abstract: The invention relates to a power roller used for a toroidal-type continuously variable transmission. This power roller has on its first side a groove for receiving a bearing, and the surface of the groove (bearing surface) has a carbon concentration which is not lower than that of the back surface of a second side opposed to the first side. The power roller has a hardened outer layer having first and second portions which are respectively defined by the bearing surface and the back surface. The first portion of the hardened outer layer has an effective depth which is not shallower than that of the second portion thereof. The power roller is prepared by the sequential steps of surface-hardening, quenching, and grinding. The surface-hardening process is one of carburizing and carbonitriding.

Abstract: Power transmission member such as gears with high breaking strength of the edge portion (A) of the root and high spalling resistance of the tooth side (B) is obtained. The work such as gears, etc. is cooled after carburization by plasma carburizing, etc. and the work surface is high-frequency hardened, and for heating at the time of high-frequency hardening, the heating conditions are set in such a manner that the heating temperature at the root becomes higher than that at the tooth side and time for holding to high temperature becomes long. This promotes solid solution of carbonate at the root and increases the remaining austenite volume after hardening (25-35% for a good-rule-of-thumb) as well as improves toughness at the edge. On the other hand, on the tooth side, the remaining austenite volume decreases (5-15% for a good-rule-of-thumb) and spalling resistance improves.

Abstract: A coil spring made of an oil-tempered steel wire with internal hardness of more than Hv 550 in cross-section, the surface hardness of the oil-tempered steel wire being determined in an extent between Hv 420 in a minimum value and hardness defined by subtraction of Hv 50 from the internal hardness in a maximum value.

Abstract: A method of heat treating steel for use in transmission gears of a vehicle including the steps of carburizing the steel to 900-950.degree. C. quenching the carburizing steel at 830-850.degree. C., reheating the steel with ammonia gas to a temperature of 800-900.degree. C., and fusing the reheated steel at a temperature of 150-230.degree. C. for providing excellent anti-abrasion, contact fatigue strength and blending fatigue strength properties, thereby controlling the quality of steel in a furnace.

Abstract: A steel article is formed of a steel material containing from about 0.08 to about 0.35 carbon and is characterized by having a plurality of carbides dispersed on at least one pre-selected surface area of the article, with the surface carbides being dispersed within a predominantly lower bainitic matrix. A method for forming the steel article having high hardness and higher toughness includes carburizing the article at a temperature and for a period of time, in an atmosphere having a carbon potential, sufficient to form carbides and austenite on at least one preselected surface of the article, and then quenching the carburized article to a temperature below the Ar.sub.1 temperature and above the M.sub.s temperature of the steel material for a time sufficient to transform a major portion of the austenite in the preselected surface area microstructure to lower bainite.

Abstract: A carburizing steel having the following chemical composition:C: 0.1 to 0.25%,Si: 0.2 to 0.4%,Mn: 0.3 to 0.9%,P: 0.02% or less,S: 0.001 to 0.15%,Cr: 0.5 to 0.9%,Mo: 0.15 to 1%,Al: 0.01 to 0.1%,B: 0.0005 to 0.009%,N: less than 0.006%, andthe balance of Fe and incidental impurities, wherein % is on a weight basis. Also disclosed are a method for the manufacture of the carburizing steel, parts of constant velocity universal joints for drive shafts made of the carburizing steel, as well as a method for the manufacture of such parts. The carburizing steel may further contain Ni: 0.3-4.0%, and one or more elements selected from the group consisting of Ti, Nb, V and Zr: 0.01-0.3% for each.

Abstract: The present invention involves a method and a device for the heat treatment of workpieces, which are heated with radiant heat generated through the combustion of gaseous fuel. Some of the workpieces are subjected to a carburisation atmosphere formed by a heated mixture of hydrocarbon containing gas and carbon dioxide, where the carbon dioxide has been separated from the exhaust gas of the gaseous fuel combustion. Other workpieces may be subjected to a nitrocarburisation atmosphere formed by a mixture of ammonia and the exhaust gas remaining after the carbon dioxide has been separated. By recycling some of the products of the combustion process, the present invention improves the efficiency of the carburisation process while reducing pollutant emissions.

Abstract: A method for treating soft magnetic parts by annealing and producing a wear guard layer, in which the soft magnetic parts are either successively annealed and provided with a wear guard layer in a reaction chamber of a treatment apparatus, or the annealing and production of a wear guard layer are done simultaneously in the reaction chamber. This avoids intermediate transportation and temporary storage as well as contamination of the parts and reduces the costs of the method. The method is especially suitable for treating soft magnetic parts of electromagnetic fuel injection valves.

Abstract: A treating material W pre-heated to a carburizing temperature of 750.degree.-950.degree. C. is heat-treated in a carburizing atmosphere directly supplied with hydrocarbon and oxidizing gases and heated to 1000.degree.-1100.degree. C. Then, the treating material W is forcibly cooled to a temperature below 600.degree. C., the treating material W is re-heated to 750.degree.-850.degree. C., and then it is hardened.Energy required to the carburization can be saved because drastic reduction of the treating time is possible.

Abstract: Metal inking rolls, particularly for flexographic printing, having: A roll structure composed of an ammonia hardenable steel, in particular stainless steel, the selection of a roll wherein the minimum thickness of the wall, if tubular, is a direct function of the diameter and an inverse function of the length of the roll, so that, when the roll is supported at its ends and stressed in the middle, on a surface relatively distributed, it may be permanently distorted in the axial direction but without distorting its cross-section; a post-engraving ionic nitriding treatment to increase the surface hardness of the screen to at least 60 HRC and a final straightening step, to reduce the screen eccentricity at least 0.02 mm.

Abstract: A manufacturing method of case-hardened parts whose chemical components comprising especially Fe, C, Si, Mn, S, Ni, Mo, Al, V and N including a step of the heat treatment 1 in which, after carburizing, carbonitriding or carburizing followed by carbonitriding steel is cooled gradually at a temperature less than 100.degree. C./minute, by another step of the heat treatment 2, in which steel is heated to a temperature higher than the Ac.sub.3 transformation point and less than 850.degree. C. and kept at the above temperature before quenching, or after keeping at the temperature, is cooled down to a level not below 600.degree. C. before quenching, or quenching is done after cooling down to and keeping the temperature not below 600.degree. C. is disclosed. This method makes the surface layer a mixture of martensite and retained austenite. Thus the case hardened steel products of high precision and high strength are obtainable.

Abstract: A process for forming a low silicon rapid-carburizing wear resistant steel article includes selecting an article formed of a steel material having less than about 0.05% silicon by weight, and carburizing the article for a preselected time and temperature to form an austenitic surface and attain a carburized case depth which is at least 5% greater than the carburized case depth of a similar article formed from a steel material having a range of about 0.09% to about 0.25% silicon by weight and being carburized at substantially same conditions of time and temperature. After quenching, the as-carburized surface transforms into a microstructure of martensite and retained austenite, being substantially free of intergranular oxides. A low silicon rapid-carburizing wear resistant steel article formed according to the present invention is particularly useful for making gears, couplings, shafts, bearings, and similar articles subjected to a combination of high bending loads, surface wear and contact fatigue.

Abstract: There is disclosed herein a steel alloy bearing having an inner race, an outer race and rolling elements comprising: at least one of said elements being made of alloy steel which constitutes from 10.0 to 18.0 wt % chromium and 0.05 to 0.30 wt % carbon, 0.10% to 2.0 wt % molybdenum, 0.15 to 1.0 wt % silicon, 0.20 to 1.5 wt % manganese, 0.8 to 1.2 wt % tungsten, 0.20 to 0.30 wt % vanadium, 0.2 to 1.0 wt % of nickel, and the remainder of said steel alloy being iron; and said at least one element having been carburized in a carbon atmosphere containing from 0.25 to about 0.40 % carbon potential.

Abstract: A process for making metal inking rolls, particularly for flexographic printing, having: A roll structure composed of an ammonia hardenable steel, in particular stainless steel, the selection of a roll wherein the minimum thickness of the wall, if tubular, is a direct function of the diameter and an inverse function of the length of the roll, so that, when the roll is supported at its ends and stressed in the middle, on a surface relatively distributed, it may be permanently distorted in the axial direction but without distorting its cross-section; a post-engraving ionic nitriding treatment to increase the surface hardness of the screen to at least 60 HRC and a final straightening step, to reduce the screen eccentricity at least 0.02 mm.

Abstract: A brightening chemical polishing solution for a hardened steel article (e.g., a carburized and quenched gear) comprises hydrofluoric acid having a molar concentration of from 0.2 to 2 mol/l, hydrogen peroxide having a molar concentration of from 0.4 to 4 mol/l, and water, a molar ratio of the hydrofluoric acid to the hydrogen peroxide being from 1:1.5 to 1:2.8. The steel article is quench hardened and is chemically polished in the solution. A shot-peening is additionally performed, prior to the polishing.

Abstract: A method of embrittling cleaned steel particles is described, followed by a grinding and sorting operation. Depending on the initial carbon content of the steel scrap, a reducing and carbon-containing atmosphere may be provided to carburize the particles as they are being embrittled. A quenching operation is provided at the end of the process to embrittle the particles and before the particles are ground. The ground grit which is produced may then be sorted by size and used as an abrasive compound, or, alternatively may be further ground and annealed in a subsequent operation to provide suitable powder for forming sintered parts. Prior to annealing the grit may be further ground in a partial oxidizing atmosphere to preoxidize the powder, in order to provide oxygen directly within the powder to react with any residual carbon so that the carbon monoxide gas can be formed and the powder can be substantially free of both carbon and oxides when the reaction is complete.

Abstract: In the preparation of a galvanized steel strip by continuously heating and anneal reducing a steel strip and subsequently admitting it, without contact with the ambient air, into a molten zinc bath to coat the strip with zinc, there is provided a method for preparing a galvanized or galvannealed steel strip having minimal uncoated defects, characterized in that a steel strip having a composition which containsup to 0.1% by weight of C,0.01 to 1.0% by weight of Si,0.05 to 2.0% by weight of Mn, andup to 0.15% by weight of P,and satisfies the following formula (1):Si/28+Mn/55+P/31.gtoreq.0.01 (1)wherein the element symbols represent the contents in % by weight of the respective elements in the steel strip is used as the starting strip to be galvanized, and the steel strip is subjected to carburizing treatment during the anneal reducing step or before the anneal reduced steel strip is admitted into the molten zinc bath.

Abstract: A case carburizable stainless steel alloy intended to be used at operating temperatures up to 700.degree. F. The alloy is able to achieve and maintain a high surface hardness when carburized and heat treated and combines high fracture toughness, hot hardness, metal-to-metal wear resistance and corrosion resistance while retaining core ductility and strength. The alloy consists essentially of (in weight percent) 0.1 to 0.25% carbon, 0 to 1% silicon, 0 to 1% manganese, 13 to 19% chromium, 1.75 to 5.25% nickel, 3 to 5% molybdenum, 0.25 to 1.25% vanadium, 5 to 14% cobalt, 0.01 to 0.1% niobium; 0 to 0.02% boron; and the balance iron and incidental impurities. The alloy is particularly suited for use in bearing applications and also in cams, shafts, gears, bolts and like articles exposed to elevated temperatures and corrosive atmospheres.

Abstract: A high tensile steel sheet excelling in workability and stretch flanging formability, which is of a composite texture composed of a ferrite phase and a 2nd phase selected from the group consisting of martensite, bainite, pearlite, retained austenite and cold-transformed ferrite, wherein the volume fraction of the 2nd phase is hoe less than about 1.3 times higher at an outer region of the steel sheet than the volume fraction of the 2nd phase in a central region of the sheet thickness.

Abstract: A method of cooling steel parts from austenitic stage to a temperature that is higher than its Ms point after carburization of said steel part to carry out diffusion transformation, then carrying out a nitriding treatment and further applying shot peening, and in order to implement said method provide a carburizing zone, a cooling zone for carrying out diffusion transformation and a nitriding treatment zone connected through opening and shutting doors, and provide feeding devices in each of said zones to feed the steel parts to the next zone.

Abstract: Steel is carburized at a temperature within the austenitic range and in an atmosphere which comprises nitrogen, hydrogen and carbon monoxide, by lowering the hydrogen concentration in the treatment atmosphere prior to cooling steel in oil, salt or water, so as to reduce the hydrogen concentration in the carburization layer of the steel, by outward diffusion of hydrogen from the carburization layer.