Abstract: Methods for forming a dual-phase magnetic component from an initial component comprising a non-magnetic austenite composition are provided. The method may include: forming a coating on a portion of the surface of the initial component to form a masked area while leaving an unmasked area thereon. Thereafter the initial component may be heated to a treatment temperature such that nitrogen diffuses out of the unmasked area of the initial component to transform the non-magnetic austenite composition to a magnetic phase in the unmasked area. Thereafter, the initial component may be cooled from the treatment temperature to form a dual-phase magnetic component having a magnetic region corresponding to the unmasked area and a non-magnetic region corresponding to the masked area.

Abstract: There is provided a precipitation hardening stainless steel with the composition: C: 0.05-0.30 wt %, Ni: 9-10 wt %, Mo: 0.5-1.5 wt %, Al: 1.75-3 wt %, Cr: 10.5-13 wt %, V: 0.25-1.5 wt %, Co: 0-0.03 wt %, Mn: 0-0.5 wt %, Si: 0-0.3 wt %, and remaining part up to 100 wt % is Fe and impurity elements, with the additional proviso that the amounts of Al and Ni also fulfil Al=Ni/4±0.5 in wt %. Further Creq is in the interval 11-15.4 wt % and Nieq is in the interval 10.5-15 wt %. There is the possibility to have very low amounts of cobalt, well below 0.01 wt %. The precipitation hardening stainless steel displays, low segregation, high yield strength at elevated temperatures, and can also suitably be nitrided. The precipitation hardening stainless steel is more economical to manufacture compared to stainless steel according to the state of the art with the same strength at elevated temperatures.

Abstract: A solid wire for electroslag welding, including Fe and, by mass % based on a total mass of the wire: C: more than 0% and 0.03% or less; Si: more than 0% and 0.10% or less; Mn: more than 0% and 0.25% or less; Ni: 10.5%-14.0%; S: more than 0% and 0.010% or less; Al: more than 0% and 0.250% or less; REM: 0.002%-0.080%; and O: more than 0% and 0.0090% or less.

Abstract: A difference between a maximum value and a minimum value of arithmetic mean roughness Ra of an annular surface region in contact with a larger flange surface, in a larger end face of the tapered roller, is not greater than 0.02 ?m. A value of a ratio R/RBASE is not smaller than 0.75 and not greater than 0.87 where R represents a set radius of curvature of the larger end face of the tapered roller and RBASE represents a distance from a point which is an apex of a cone angle of the tapered roller to the larger flange surface of the inner ring. A ratio Rprocess/R is not lower than 0.5 where Rprocess represents an actual radius of curvature after grinding of the larger end face of the tapered roller and R represents a set radius of curvature.

Abstract: The present invention relates to a method for producing an article out of a maraging steel, wherein the article is successively subjected to a solution annealing and heat treatment, wherein the steel has the following composition in weight percent: C=0.01-0.05 Si=0.4-0.8 Mn=0.1-0.5 Cr=12.0-13.0 Ni=9.5-10.5 Mo=0.5-1.5 Ti=0.5-1.5 Al=0.5-1.5 Cu=0.0-0.05 Residual iron and smelting-induced impurities.

Abstract: A control method according to one aspect of the technology is for use where a power supply of an apparatus having a first application and a second application is turned off during display of a screen of the second application and remains off, the first application being used to view a program, the second application being different from the first application. The control method includes: in a case where a power button is pressed, turning on the power supply of the apparatus to start simultaneously the second application and to display the screen thereof; and in a case where a channel selection button is pressed, turning on the power supply of the apparatus to start simultaneously the first application and to display an image of the program distributed on a selected channel.

Abstract: Disclosed is a method for manufacturing high-carbon bearing steel, which include: heating a billet at a temperature of about 950 to 1,050° C. for about 70 to 120 minutes, rolling the billet to manufacture a wire rod, winding the wire rod to manufacture a wire rod coil, cooling the wire rod coil, and subsequently heat treating the wire rod coil for spheroidizing and carbonitriding, respectively. The bearing steel may include an amount of about 0.9 to 1.3 wt % of carbon (C), an amount of about 1.1 to 1.6 wt % of silicon (Si), an amount of about 1.0 to 1.5 wt % of manganese (Mn), an amount of about 1.5 to 1.9 wt % of chromium (Cr), an amount of about 0.2 to 0.6 wt % of nickel (Ni), an amount of about 0.1 to 0.3 wt % of molybdenum (Mo), and the balance iron (Fe) based on the total weight thereof.

Abstract: A series of welding filler wires with innovative composition design for fusion welding precipitation-hardened lightweight austenitic Fe—Mn—Al—C alloys. The first class of the welding filler wires is composed of 23-34 wt. % Mn, 7.5-11.5 wt. % Al, 1.35-1.95 wt. % C, with the balance being essentially Fe. After fusion welding, there are high-density of nano-sized (˜3-5 nm) (Fe,Mn)3AlC carbides (?-carbides) uniformly distributed within the austenite dendrite cells in the fusion zone (FZ). The amount of nano-sized (˜6-10 nm) ?-carbides existing within the eutectic regions is significantly increased and the size of the austenite dendrite cells is substantially reduced. The second class of welding filler wires has the composition of 23-34 wt. % Mn, 7.5-11.5 wt. % Al, 1.40-1.95 wt. % C, 0.1-2.5 wt. % Ti, 0.1-3.0 wt. % Nb, 0.1-2.5 wt. % V, with the balance being essentially Fe.

Abstract: A hot forged steel material in the present embodiment includes a chemical composition that consists of, in mass %, C: 0.14 to 0.20%, Si: 0.20 to 1.00%, Mn: 1.00 to 1.90%, P: 0.030% or less, S: 0.030% or less, V: 0.16 to 0.30%, Al: 0.015 to 0.050%, N: 0.0050 to 0.0250%, Cr: 0.10 to 0.30%, Cu: 0 to 0.10%, and Nb: 0 to 0.10%, with the balance being Fe and impurities, and that satisfies Formula (1) and Formula (2), wherein a grain size number of ferrite in the steel is 9.0 or more, and an absorbed energy at ?30° C. is 100 J or more in the Charpy impact test using a V notch specimen. 0.36?C+(Si+Mn)/6+(Cr+V)/5+Cu/15<0.68??(1) 51/12×C?V?0.

Abstract: A nitrided part and soft nitrided part with excellent wear resistance and pitting resistance and a nitriding method and soft nitriding method are provided, specifically, a nitrided part or soft nitrided part made by a steel material comprising, by mass %, C: 0.05 to 0.3%, Si: 0.05 to 1.5%, Mn: 0.2 to 1.5%, P: 0.025% or less, S: 0.003 to 0.05%, Cr: 0.5 to 2.0%, Al: 0.01 to 0.05%, and N: 0.003 to 0.025% and having a balance of Fe and impurities, wherein, the surface layer comprises a compound layer containing iron, nitrogen, and carbon and a nitrogen diffusion layer positioned below the compound layer, the compound layer comprises an ? single phase, the ? single phase has a thickness of 8 to 30 ?m and a Vicker's hardness of 680 HV or more, and the ? single phase has a volume ratio of pores of less than 10%.

Abstract: A hot-work mold steel includes 0.37 to 0.46 wt % of carbon (C), 0.25 to 0.5 wt % of silicon (Si), 0.36 to 0.56 wt % of manganese (Mn), 2.0 to 5.0 wt % of chromium (Cr), 1.4 to 2.6 wt % of molybdenum (Mo), 0.4 to 0.8 wt % of vanadium (V), 0.0007 to 0.004 wt % of boron (B), 0.002 to 0.022 wt % of aluminum (Al), 0.001 to 0.09 wt % of titanium (Ti) and the remainder of iron (Fe) and inevitable impurities. The hot-work mold steel exhibits superior thermal conductivity, hardenability, durability, and nitriding characteristics, and increased resistance to heat check and melt-out. A die-casting mold made of the steel has improved thermal conductivity regardless of mold size and a prolonged life cycle and can improve the surface quality in manufactured parts.

Abstract: To provide a piston ring free from microwelding to a piston while exhibiting excellent wear resistance in side surfaces, for a long period of use in a high-temperature, high-pressure environment, and its production method, a nitride layer is formed on at least one of upper and lower side surfaces of the piston ring, and then subjected to a phosphate chemical conversion treatment, such that the nitride layer has at least one of granular and vermicular surface forms.

Abstract: A nitrided component has a chemical composition consisting of, by mass percent, C: 0.07-0.14%, Si: 0.10-0.30%, Mn: 0.4-1.0%, S: 0.005-0.030%, Cr: 1.0-1.5%, Mo: ?0.05% (including 0%), Al: 0.010% or more to less than 0.10%, V: 0.10-0.25%, optionally at least one element selected from Cu: ?0.30% and Ni: ?0.25%, [0.61Mn+1.11Cr+0.35Mo+0.47V?2.30], and the balance of Fe and impurities. P, N, Ti and O among the impurities are P: ?0.030%, N: ?0.008%, Ti: ?0.005%, and O: ?0.0030%. The nitrided composition is suitable for use as an automobile ring gear. The nitrided component has a surface hardness of 650-900 HV, core hardness being ?150 HV, effective case depth of ?0.15 mm, has excellent bending fatigue strength and surface fatigue strength although the content of Mo is as low as ?0.05% and has a small amount of expansion caused by nitriding.

Abstract: A compressor includes a cylinder including a cylinder chamber, a piston movably arranged relative to the cylinder in the cylinder chamber, and a sliding member slideable against the cylinder and the piston in the cylinder chamber. The cylinder and the piston are constructed from an Al—Si alloy having a Si content exceeding 12.6 wt %, which is a eutectic point. The sliding member is constructed from steel and has a surface layer including a sliding surface slideable against the cylinder and the piston. The surface layer is treated so as to have greater hardness than hardness of proeutectic Si contained in the Al—Si alloy, and the surface layer has hardness of at least Hv 1000 in the sliding surface.

Abstract: A spray-formed high-speed steel includes chemical components by mass percent of: C: 0.85-1.65%, Si: 0.1-1.2%, Cr: 3.5-8.0%, W: 4.0-6.5%, Mo: 4.5-7.0%, V: 1.0-4.0%, Co: 1.0-8.0%, Mn: 0.2-0.8%, and Nb: 0.2-3.5%, with balance of iron and impurities.

Abstract: A novel FeMnAlC alloy, comprising 23˜34 wt. % Mn, 6˜12 wt. % Al, and 1.4˜2.2 wt. % C with the balance being Fe, is disclosed. The as-quenched alloy contains an extremely high density of nano-sized (Fe,Mn)3AlCx carbides (??-carbides) formed within austenite matrix by spinodal decomposition during quenching. With almost equivalent elongation, the yield strength of the present alloys after aging is about 30% higher than that of the optimally aged FeMnAlC (C?1.3 wt. %) alloy systems disclosed in prior arts. Moreover, the as-quenched alloy is directly nitrided at 450˜550° C., the resultant surface microhardness and corrosion resistance in 3.5% NaCl solution are far superior to those obtained previously for the optimally nitrided commercial alloy steels and stainless steels, presumably due to the formation of a nitrided layer consisting predominantly of AlN.

Abstract: A steel for cold forging/nitriding has, by mass percent, C: 0.01 to 0.15%, Si?0.35%, Mn: 0.10 to 0.90%, P?0.030%, S?0.030%, Cr: 0.50 to 2.0%, V: 0.10 to 0.50%, Al: 0.01 to 0.10%, N?0.0080%, and O?0.0030%, further according to need a specific amount of one or more elements selected from Mo, Cu, Ni, Ti, Nb, Zr, Pb, Ca, Bi, Te, Se and Sb, with the balance being Fe and impurities, and further satisfying the conditions of [399×C+26×Si+123×Mn+30×Cr+32×Mo+19×V?160], [20?(669.3×logeC?1959.6×logeN?6983.3)×(0.067×Mo+0.147×V)?80], [140×Cr+125×Al+235×V?160] and [90?511×C+33×Mn+56×Cu+15×Ni+36×Cr+5×Mo+134×V?170] are excellent in cold forgeability and machinability after cold forging.

Abstract: To provide an oil-well steel pipe having excellent SSC resistance. The oil-well steel pipe according to the present invention contains, by mass percent, C: 0.15 to 0.35%, Si: 0.1 to 0.75%, Mn: 0.1 to 1.0%, Cr: 0.1 to 1.7%, Mo: 0.1 to 1.2%, Ti: 0.01 to 0.05%, Nb: 0.010 to 0.030%, Al: 0.01 to 0.1%, P: at most 0.03%, S: at most 0.01%, N: at most 0.007%, and O: at most 0.01%, the balance being Fe and impurities. The Ti content and the Nb content in a residue obtained by bromine-methanol extraction satisfy equation (1): 100×[Nb]/([Ti]+[Nb])?27.5??(1) where the Ti content (mass %) and the Nb content (mass %) in the residue are substituted for [Ti] and [Nb].

Abstract: A hot-rolled steel sheet for nitriding or a cold-rolled steel sheet for nitriding, in which a dislocation density within 50 ?m in the sheet thickness direction from the surface is not less than 2.0 times nor more than 10.0 times as compared to a dislocation density at the position of ¼ in the sheet thickness direction; and a method of manufacturing the same. The manufacturing method comprises, on a hot-rolled steel sheet or a cold-rolled steel sheet, performing pickling, and then performing skin pass rolling under the condition that a reduction ratio is 0.5 to 5.0% and FIT, defined as a ratio of a line load F (kg/mm) of a rolling mill load divided by a sheet width of the steel sheet and a load T (kg/mm2) per unit area to be applied in the longitudinal direction of the steel sheet, is 8000 or more.

Abstract: To provide a price-competitive compression ring having excellent thermal conductivity and thermal sag resistance, which can be used in a high-thermal-load environment of high-compression-ratio engines, steel identified by the material number of SUP10 in JIS G 4801, which contains small amounts of alloying elements, is used, and a piston ring wire is annealed before an oil-tempering treatment such that spheroidal cementite having an average particle size of 0.1-1.5 ?m is dispersed in a tempered martensite matrix, thereby suppressing the movement of dislocation and creep even at 300° C., and improving thermal sag resistance.

Abstract: A steel comprises, by mass percent, C: 0.10 to 0.15%, Si: not less than 0.02% and less than 0.10%, Mn: more than 0.90% and not more than 2.50%, P?0.030%, S?0.050%, Cr: 0.80 to 2.0%, V: 0.05 to 0.50%, Al: 0.01 to 0.07%, N?0.0080%, O?0.0030%, and one or more selected from Mo, Cu, Ni, Ti, Nb, Zr, Pb, Ca, Bi, Te, Se and Sb, the balance being Fe and impurities. The composition satisfies [35?Mn/S?200], [20?(669.3×loge C?1959.6×loge N?6983.3)×(0.067×Mo+0.147×V)?80], [140×Cr+125×Al+235×V?160] and [150?511×C+33×Mn+56×Cu+15×Ni+36×Cr+5×Mo+134×V?200].

Abstract: Processes for protecting steel chains from corrosion and steel chains thus protected are provided. The process includes using finite element analysis to determine stress levels within links of a steel chain having a plurality of connected links. Regions of each link of the chain corresponding to high stress levels are identified. Target areas corresponding to the regions identified are indicated for coating each link of the chain with a sacrificial coating. Thermally sprayed alumina can be used as the sacrificial coating.

Abstract: A coated piston ring having a base body of chromium steel with more than 10 wt.-% chromium and having an inner circumferential surface, a first flank surface, a second flank surface and an outer circumferential surface. The first flank surface comprises a nitride diffusion layer with a layer thickness of from 5-300 ?m, a nitride connecting layer with a layer thickness of from 0.5-15 ?m on the nitride diffusion layer, and an oxide layer with a layer thickness of from 0.05-3 ?m on the nitride connecting layer. The second flank surface comprises the nitride diffusion layer, and the outer circumferential surface comprises the nitride diffusion layer and a chromium solid particle layer with 0.1-30 vol.-% solid particles, relative to the total volume of the chromium solid particle layer on the nitride diffusion layer.

Abstract: A multi-element alloy material consists of Al, Cr, Fe, Mn, Mo and Ni. From an outer surface to a center of the multi-element alloy material exhibits a hardness gradient from high to low. A method of manufacturing a multi-element alloy material with hardness gradient includes melting and casting metals with a metal combination of Al, Cr, Fe, Mn, Mo and Ni to form an alloy body, subjecting the alloy body to a homogenization treatment, and subjecting the homogenized alloy body to a high temperature treatment to perform precipitation hardening at surface of the alloy body by heating, thereby forming a multi-element alloy material having hardness gradient.

Abstract: A method for method for solution hardening of a cold deformed workpiece of a passive alloy containing at least 10% chromium, which method includes dissolving at least nitrogen in the workpiece at a temperature T1, which is higher than the solubility temperature for carbide and/or nitride and lower than the melting point of the passive alloy, wherein dissolution of nitrogen at temperature T1 is performed to obtain a diffusion depth in the range of 50 ?m to 5 mm, and cooling the workpiece after the dissolution step at temperature T1 to a temperature which is lower than the temperature at which carbides and/or nitrides form in the passive alloy, wherein the cooling step takes place in an inert gas not containing nitrogen. Further, a member, such as a lock washer for securing bolts or nuts prepared using the method.

Abstract: This invention relates to a partially carbonitriding heat treated stainless steel ferrule, having a first region with a first hardness and a second region with a second hardness, wherein the first region includes a nitrogen layer having a nitrogen concentration higher than a carbon concentration, and a carbon layer formed under the nitrogen layer and having a carbon concentration higher than a nitrogen concentration, so that the first hardness is greater than the second hardness. Thereby, partial heat treatment is effective at preventing rotational torque of the region, except for the portion to be heat treated, from increasing due to the total hardening.

Abstract: The invention relates generally to welding and, more specifically, to welding wires for arc welding, such as Gas Metal Arc Welding (GMAW) or Flux Core Arc Welding (FCAW). A disclosed tubular welding wire has a sheath and a core, and the tubular welding wire includes an organic stabilizer component, a rare earth component, and a corrosion resistant component comprising one or more of: nickel, chromium, and copper.

Abstract: A nitrocarburized crankshaft member made of a steel having essentially ferrite and perlite, and at least a portion of a steel surface thereof having a ferrite surface area of 50% or greater that is imparted with a nitrocarburized hard layer. The steel consists of C, Si, Mn, Cu, Ni, and Cr as required elements and Mo, N, s-Al, Ti, Pb, Bi, and Ca as optional elements that may be included, and Fe and inevitable impurities. C is within a range of 0.25 to 0.32%. The nitrocarburized crankshaft member includes a thickness of a surface compound layer of the nitrocarburized hard layer of 10 to 35 ?m that is formed during establishment of a diffusion depth of a nitrogen diffusion zone below the surface compound layer of 700 ?m or greater.

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 steel comprises, by mass percent, C: 0.10 to 0.15%, Si: not less than 0.02% and less than 0.10%, Mn: more than 0.90% and not more than 2.50%, P?0.030%, S?0.050%, Cr: 0.80 to 2.0%, V: 0.05 to 0.50%, Al: 0.01 to 0.07%, N?0.0080%, O?0.0030%, and one or more selected from Mo, Cu, Ni, Ti, Nb, Zr, Pb, Ca, Bi, Te, Se and Sb, the balance being Fe and impurities. The composition satisfies [35?Mn/S?200], [20?(669.3×logeC?1959.6×logeN?6983.3)×(0.067×Mo+0.147×V)?80], [140×Cr+125×Al+235×V?160] and [150?511×C+33×Mn+56×Cu+15×Ni+36×Cr+5×Mo+134×V?200].

Abstract: A method for producing a welded part from two components, where at least one of the components has a hardened surface. The method can include case hardening the surface of one of the components using a salt bath nitriding process and then welding the case hardened first component to the second component by gas metal arc welding (GMAW).

Abstract: A nitrided steel member including an iron nitride compound layer formed on a surface of a steel member having predetermined components, wherein: in X-ray diffraction peak intensity IFe4N (111) of a (111) crystal plane of Fe4N and X-ray diffraction peak intensity IFe3N (111) of a (111) crystal plane of Fe3N, which are measured on a surface of the nitrided steel member by X-ray diffraction, an intensity ratio expressed by IFe4N (111)/{IFe4N (111)+IFe3N (111)} is 0.5 or more; Vickers hardness of the iron nitride compound layer is 900 or less, Vickers hardness of a base metal immediately under the iron nitride compound layer is 700 or more, and a difference between the Vickers hardness of the iron nitride compound layer and the Vickers hardness of the base metal is 150 or less; and a thickness of the iron nitride compound layer is 2 to 17 ?m.

Abstract: A steel which is excellent in delayed fracture resistance containing, by mass %, C: 0.10 to 0.55%, Si: 0.01 to 3%, and Mn: 0.1 to 2%, further containing one or more of Cr: 0.05 to 1.5%, V: 0.05 to 0.2%, Mo: 0.05 to 0.4%, Nb: 0.001 to 0.05%, Cu: 0.01 to 4%, Ni: 0.01 to 4%, and B: 0.0001 to 0.005%, and having a balance of Fe and unavoidable impurities, the structure being a mainly tempered martensite structure, the surface of the steel being formed with (a) a nitrided layer having a certain thickness range and a nitrogen concentration higher than the nitrogen concentration of the steel by 0.02 mass % or more and (b) a low carbon region having a certain depth range from the surface of the steel and having a carbon concentration of 0.9 time or less the carbon concentration of the steel.

Abstract: This gear has a predetermined chemical composition and has, in a surface-layer part, a texture of tempered martensite and/or tempered bainite and a steel material texture in which retained austenite exists in 1-10% by area percentage and in which a carbide is deposited in at least 5% by area percentage, and the nitrogen content at a depth of 20 ?m below the surface is 2.0-6.0%. Thus, a gear that achieves even better seizing resistance in a power transmission part subjected to high rotation and high slippage and using a low-kinematic-viscosity lubricating oil is provided.

Abstract: A rolling bearing (6), in particular for the mounting of the shaft of a turbocharger, which rolling bearing includes a bearing ring (1) and a number of rolling bodies (9). The bearing ring (1) is formed from a steel which comprises, as alloy constituents, 0.05 to 0.65 wt % carbon, 0.5 to 5.0 wt % chromium, up to 1.0 wt % molybdenum, up to 1.0 wt % vanadium, and up to 1.0 wt % aluminum. The surface of the bearing ring (1) has a hardened surface layer (2) which comprises nitrites and which comprises a diffusion layer (3) and a connecting layer (4) situated above said diffusion layer. The surface layer (2) has a thickness of up to 1 mm. The invention also relates to a method for producing a corresponding bearing ring (6).

Abstract: A steel material for nitriding has a composition comprising, by mass percent, C: more than 0.15% and not more than 0.35%, Si?0.20%, Mn: 0.10 to 2.0%, P?0.030%, S?0.050%, Cr: 0.80 to 2.0%, V: 0.10 to 0.50%, Al: 0.01 to 0.06%, N?0.0080%, O?0.0030%, and optionally one or more elements of Mo, Cu, Ni, Ti, Nb, Zr, Pb, Ca, Bi, Te, Se and Sb, the balance being Fe and impurities. The composition satisfies the conditions of [20?(669.3×logeC?1959.6×logeN?6983.3)×(0.067×Mo+0.147×V)?80] and [140×Cr+125×Al+235×V?160]. The microstructure is a ferritic-pearlitic structure, a ferritic-bainitic structure, or a ferritic-pearlitic-bainitic structure. The area fraction of ferrite is 20% or more and the precipitate content of V is 0.10% or less.

Abstract: A hard and wear resistant coating for a body includes at least one metal based nitride layer having improved high temperature performance. The layer is (Zr1-x-zSixMez)Ny with 0<x<0.30, 0.90<y<1.20, 0?z<0.25, and Me is one or more of the elements Y, Ti, Nb, Ta, Cr, Mo, W and Al, comprised of a single cubic phase, a single hexagonal phase or a mixture thereof, with a cubic phase of a sodium chloride structure and a thickness between 0.5 ?m and 15 ?m. The layer is deposited using cathodic arc evaporation and is useful for metal cutting applications generating high temperatures.

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

Abstract: Provided is a case hardening steel which allows effective inhibition of abnormal grain growth during carburizing treatment or the like and makes it possible to solve the problem of abnormal grain growth-induced reduction in characteristics. In the case hardening steel, a total amount of TiC, ZrC and AlN which are precipitate particles contained in 100 g of a steel material after subjecting the case hardening steel to hot rolling is 3.5×10?4 mole or less.

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

Abstract: This case hardened steel has a composition including, in mass %: C: 0.05 to 0.45%; Si: 0.01 to 1.0%; Mn: over 0 to 2.0%; Al: 0.001 to 0.06%, N: 0.002 to 0.03%, S: over 0 to 0.1%, P: over 0 to 0.05%; and balance: Fe and inevitable impurities. Equation (1) described below and Equation (2) described below are satisfied in equiaxed zone, or Equation (3) described below is satisfied in columnar zone. Re=(Ae/Ao)×100?30%??Equation (1) (Cmin,1/Co)?0.95??Equation (2) (Cmin,2/Co)?0.

Abstract: Disclosed are a method for adjusting the pore size of a porous metal material and the pore structure of a porous metal material. The method comprises: permeating at least one element into the surface of the pores of the material to generate a permeated layer on the surface of the pores, so that the average pore size of the porous material is reduced to within a certain range, thus obtaining a pore structure of the porous metal material having the pores distributed on the surface of the material and the permeated layer provided on the surface of the pores.

Abstract: An outer ring, an inner ring, and a ball, each of which is a bearing part, are made of a quench-hardened steel containing not less than 0.90 mass % and not more than 1.05 mass % of carbon, not less than 0.15 mass % and not more than 0.35 mass % of silicon, not less than 0.01 mass % and not more than 0.50 mass % of manganese, and not less than 1.30 mass % and not more than 1.65 mass % of chromium with the rest consisting of an impurity. A contact surface thereof with another part has a nitrogen concentration of not less than 0.25 mass %. A remaining austenite amount in the contact surface is not less than 6 volume % and not more than 12 volume %.

Abstract: Provided is a method of manufacturing a nitrocarburized crankshaft which is obtained by subjecting a bainitic microalloyed steel to a forging and a machining, and further subjecting the bainitic microalloyed steel to at least a strain releasing heat treatment and a subsequent nitrocarburizing treatment, the bainitic microalloyed steel containing, as essentially added elements, in terms of mass %: 0.10% to 0.40% of C; 0.10% to 1.0% of Si; 1.0% to 2.0% of Mn; 0.05% to 0.40% of Mo; and 0.05% to 0.40% of V, and the bainitic microalloyed steel optionally further containing, as arbitrarily added elements, in terms of mass %: 0.01% to 0.1% of S; 0.005% to 0.2% of Ti; 0.001% to 0.03% of Al; 0.50% or less of Cr; 0.5% or less of Cu; and 0.5% or less of Ni, with the balance being Fe and unavoidable impurities.

Abstract: The present invention provides a steel for nitriding with a composition including, by mass %: C: 0.10% to 0.20%; Si: 0.01% to 0.7%; Mn: 0.2% to 2.0%; Cr: 0.2% to 2.5%; Al: 0.01% to less than 0.19%; V: over 0.2% to 1.0%; Mo: 0% to 0.54%; N: 0.001% to 0.01%; P limited to not more than 0.05%; S limited to not less than 0.2%; and a balance including Fe and inevitable impurities, the composition satisfying 2?[V]/[C]?10, where [V] is an amount of V by mass % and [C] is an amount of C by mass %, in which the steel for nitriding has a microstructure containing bainite of 50% or more in terms of an area percentage.

Abstract: An outer ring, an inner ring and a ball are each constituted of steel containing at least 0.60 mass % and not more than 1.50 mass % of carbon, at least 0.15 mass % and not more than 2.50 mass % of silicon, at least 0.30 mass % and not more than 1.50 mass % of manganese, and at least 0.20 mass % and not more than 2.00 mass % of chromium with the rest consisting of an impurity. A nitrogen concentration in surface layer portions is at least 0.3 mass %. An average quantity of residual austenite as a whole in each of the outer ring, the inner ring and the ball is not more than 20 volume %.

Abstract: A method for producing a case-hardened martensitic stainless steel article includes: providing an article comprised, at least in part, of a martensitic stainless steel, carburizing the article within a temperature range of 1625° F.-1680° F. (885° C.-916° C.), and then carbo-nitriding the article within a temperature range of 1575° F.-1625° F. (857° C.-885° C.). An article, such as a bearing ring, comprising such a case-hardened martensitic stainless steel is also disclosed.

Abstract: A roller bearing having two cooperating rolling parts of which one is of ceramic and the other of a steel. The steel part is of such structure and/or material and/or is so produced to cause residual compressive stresses to form beneath the contact surface of the steel part, at least in a load-free state, down to a depth.

Abstract: The present invention provides spring use heat treated steel which is cold coiled, can achieve both sufficient atmospheric strength and coilability, has a tensile strength of 2000 MPa or more, and can improve the performance as a spring by heat treatment after spring fabrication, that is, high strength spring-use heat treated steel characterized by containing, by mass %, C: 0.45 to 0.9%, Si: 1.7 to 3.0%, and Mn: 0.1 to 2.0%, restricting N: to 0.007% or less, having a balance of Fe and unavoidable impurities, and satisfying, in terms of the analyzed value of the extracted residue after heat treatment, [amount of Fe in residue on 0.2 ?m filter/[steel electrolysis amount]×100?1.1.

Abstract: A forged, microalloyed, and nitrided steel part is disclosed to have a composition including 0.20-0.40 wt. % C, 0.50-1.60 wt. % Mn, 0.40-1.50 wt. % Cr, 0.07-0.30 wt. % Al, 0.03-0.20 wt. % V, 0.10-0.40 wt. % Si, and a balance of Fe and incidental impurities. The part may be produced by heating the steel part to austenization temperature of approximately 1100 degrees C. to 1260 degrees C., hot forging the steel part, controlled air cooling the steel part after hot forging at a rate falling approximately in the range from 1 degree C. per second to 5 degrees C. per second as the steel part cools from approximately 900 degrees C. to approximately 500 degrees C. to produce a predominantly bainitic microstructure of greater than approximately 50% bainite. The steel part may then be machined to a desired configuration, and nitrided by heating in an atmosphere containing ammonia.