Abstract: In the production of high permeability electrical steel, the control of condition of thin slab continuous casting allows to obtain advantageous solidification structures and precipitates. This, in turn, allows to decritize the process for controlling the grain dimensions and to add nitrogen to the cold rolled sheet, such as to immediately form aluminum nitride.

Abstract: A member used in contact with a hot dip galvanizing bath, such as a sinker roll, a support roll or a bearing, is produced by nitriding stainless steel to form a nitride layer and a nitrogen-diffused layer on the surface thereof. The member used in contact with a hot dip galvanizing bath is formed on its surface with the nitride layer by nitriding it in a salt bath containing a cyanide, a cyanate, a carbonate and the like or by heat-treating it in an atmosphere containing ammonium or nitrogen.

Abstract: In the production of grain oriented electrical steel sheet, controlling the condition of thin slab continuous casting results in advantageous solidification structures and precipitates. The steel has an initial content of carbon less than 300 ppm and an initial content of acid-soluble aluminum higher than that normally used for said type of steel. During the final processing steps, the annealed sheet is nitrided through a limited amount of nitrogen. This, in turn, renders the process for controlling the grain dimensions much less critical and results in a constant quality product.

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 dispersion hardened FeCrAl-alloy and method of its production which includes in one step, forming a nitride dispersion in a FeCr-alloy, whereby this nitride dispersion includes one or more of the basic elements hafnium, titanium and zirconium, and, in a later step aluminum is added to the nitrided FeCr-alloy. The unfavorable formation of aluminum nitrides has thereby been avoided by adding aluminum after the nitriding. A FeCrAl-alloy with high high temperature strength and high creep strength has thereby been achieved.

Abstract: The high-strength valve spring uses, as the material, a steel containing 0.5-0.8% C, 1.2-2.5 wt % Si, 0.4-0.8 wt % Mn, 0.7-1.0 wt % Cr, balance Fe and inevitable impurities, where, in the inevitable impurities, Al is no more than 0.005 wt % and Ti is no more than 0.005 wt %, and the largest non-metallic inclusion is 15 &mgr;m. In the oil tempering treatment, the heating temperature at hardening is between 950-1100° C., and nitriding treatment is performed after coiling. It is preferable to nitride at a temperature no lower than 480° C. Since the material is a high-silicon steel, the tempering temperature can be set at a higher temperature, and the nitriding temperature can be so high. In another way, after coiling, the spring is subjected to shot peening at least twice with shot particles of hardness 720 Hv or higher to produce a compressive residual stress of 85 kgf/mm2 at around surface.

Abstract: A method for improving the corrosion resistance, increasing the hardness, providing superior ductility, and reducing surface-cracking of a diffusion coating by nitriding and heating-treating the diffusion coating is disclosed. The nitriding and heat-treating may occur subsequently or simultaneously. Further, the disclosed method may be practiced subsequent to or incorporated as an intergral part of any known diffusion coating process which utilizes a heating step in a furnace having a cover gas.

Abstract: A motor rotary shaft according to the present invention is constructed only at the surface layer of a journal portion with a hard nitride layer, so that the resultant motor rotary shaft is available at a low cost, not so heavy and excellent in durability in comparison with a case employing a hard material for the whole motor rotary shaft. Also, a method of manufacturing a motor rotary shaft according to the present invention employs fluorinating process prior to nitriding process to change a passive coat layer such as oxide layer on the surface of the journal portion to a fluoride layer, which protects the same surface. Therefore, even when there is space of time between formation of fluoride on the surface of the journal portion and nitriding process, the fluoride layer protects and keeps the surface of the journal portion in a favorable condition, resulting in that re-formation of oxide layer on that surface is prevented.

Abstract: Rolling-element bearing components made from high quality steel are subjected to ion nitriding in a plasma as a final step in the manufacturing process to produce a layer with a hardness around 800-1200 HV with a depth no more than 150 &mgr;m. By controlling the conditions no friable surface layer is created and no further steps need to be performed on the component.

Abstract: The present invention generally describes methods for modifying MCrAlY coatings by using gaseous carburization, gaseous nitriding or gaseous carbonitriding. The modified MCrAlY coatings are useful in thermal barrier coating systems, which may be used in gas turbine engines.

Abstract: A method of treating a metallic machine part to increase wear life and to change surface appearance comprising the steps of roughening the surface, thereafter changing its color by case hardening and, subsequently, increasing the lubricity of the case hardened surface by coating the surface with a pigmented, solid perfluorinated lubricant of a color comparable to the color of the case hardened surface.

Abstract: A substantially carbon free (e.g. 50-80 ppm carbon max.) iron base melt is strip cast to provide a cast strip having a low strength, high ductility, essentially ferrite matrix substantially free of hardening acicular ferrite, bainite and martensite phases. The strip strength may be enhanced by subjecting the strip to a carburizing or nitriding treatment either directly after casting or after casting followed by cold rolling and annealing.

Abstract: A gear having high pitching resistance, sufficient surface hardness, sufficient hardened depth, high abrasion resistance, high breakage resistance, high fatigue resistance, and low gear noises. A material equivalent to JIS-SCM420 is soft nitrided for two hours in a mixture gas containing 45 to 65 volume % of residual NH.sub.3 at a gas temperature of 530 to 565.degree. C., thus producing a compound layer having a hardness equal to or higher than that of the material plus Hv 50 and a thickness of 200 .mu.m or more.

Abstract: By forming a Cr playing layer on the surface of a metal and forming a CrN film by nitriding the surface thereof, it is possible to improve the surface hardness, wear resistance, corrosion resistance, etc., of the metal; wherein the nitriding treatment of the Cr plating layer surface is carried out by a method of heating in a nitrided atmosphere, preferably heated in a nitrided atmosphere which includes an ammonia decomposed gas treated in advance with an ammonia decomposition catalyst as a nitrogen source; in addition it is preferable that before the nitriding treatment, the Cr plating layer surface is purified and activated by heating in a halogen compound or a reacting gas which includes halogen.

Abstract: A method and apparatus for making a piston ring in which a metal strip having a first coefficient of expansion is coiled about a special mandrel having a second greater coefficient of expansion and a threaded form that has a zero helix angle along most of its circumference or perimeter and then a relatively steep helix angle for a short distance.

Abstract: In a manufacturing method of a valve spring, a coiled valve spring made of an oil-tempered wire is applied with nitriding treatment and is supported to be rotated about its center axis. During a shot peening process of the coiled valve spring, cut wires of Hv 650 to 850 in hardness and 1.0 to 0.6 mm in diameter are shot to the coiled valve spring at a first step, in a roller-type shot machine and cut wires of Hv 650 to 850 in hardness and 0.4 to 0.2 mm in diameter are shot to the coiled valve spring at a second step in a tumbling shot machine, the time for the second step being longer than the time for the first step.

Abstract: A crank shaft is constructed only at the surface layer of a journal portion with a hard nitride layer, so that the resultant crank shaft is available at a low cost, not so heavy and excellent in durability in comparison with a case employing a hard material for the whole crank shaft. Also, a method of manufacturing a crank shaft according to the present invention employs fluorinating process prior to nitriding process to change a passive coat layer, such as oxide layer on the surface of the journal portion to a fluoride layer, which protects the same surface. Therefore, even when there is space of time between formation of fluoride on the surface of the journal portion and nitriding process, the fluoride layer protects and keeps the surface of the journal portion in a favorable condition, resulting in that re-formation of oxide layer on that surface is prevented.

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: The object of the present invention is to provide a simple, inexpensive method of surface treatment capable of improving the strength and smoothness of fishing tackle parts made of alloy steel containing chrome. The method of surface treatment for a fishing tackle part made of alloy steel containing chrome according to the present invention is characterized in that the surface of the fishing tackle part made of alloy steel containing chrome is nitrided to form a diffused layer of chromium nitride from the surface of said part inwards, and then said surface is covered with a layer of titanium nitride.

Abstract: A method for shot peening a hard metal product that has a hardened surface. The method includes projecting shot on the hardened surface of the hard metal product. The ratio of the Vickers hardness of the shot to that of the hardened surface is 0.8-1.6, and the diameter of the shot is 30-250.mu..

Abstract: A rare earth-iron-nitrogen based magnetic material has superior magnetic properties. A method of manufacturing the rare earth-iron-nitrogen based magnetic material controls the decline in the magnetic properties of the material during pulverizing processes, and pulverizes the material to a critical particle dimension for single-domain behavior. The fragility of the material is increased since the material includes at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W at 0.05-5% atomic percentage. The material is pulverized by a gas current type jet mill. Sample powder injected from a hopper is introduced from a supply mouth to a pulverizing chamber by nitrogen gas spouting from a pressure nozzle, and the powder is then accelerated to acoustic velocity by high pressure nitrogen gas spouting from gliding nozzles. As a result, the powder particles collide with each other.

Abstract: A composite diffusion type nitriding method and a composite diffusion type nitriding apparatus of the present invention are effectively used for nitriding various materials, such as machine parts, as well as a material which is difficult for nitriding by a conventional method. The composite diffusion nitriding apparatus is formed of a container filled with solid granular materials, a furnace for housing the container therein, a nitriding gas introduction path for introducing the nitriding gas into the container, and an exhausting path for exhausting the gas from the container. In the method, the material to be nitrided is placed in the solid granular materials, and the nitriding gas is supplied to flow through the solid granular materials to thereby nitride the material.

Abstract: The adhesive strength and hardness of chromium nitride(CrN) film deposited on SKD 61 tool steel was significantly enhanced by a nitriding process on the surface the tool steel before coating with a CrN film. These nitriding processes included nitrocarburing, gas nitriding, and plasma nitriding, respectively. After nitriding, the surface of tool steel was repolishing with grits #600, #1000, #1800 of SiC grinding paper, as well as #1000 grinding paper and diamond paste, respectively. After repolishing, the CrN film was deposited by the cathodic arc ion plating deposition process at low temperatre of 200.degree. C. The present invention was related to the process modification for enhancing the adhesive strength and surface hardness of CrN film deposited on tool steels. This method included a nitriding process and a repolishing followed by the cathodic arc ion plating deposition.

Abstract: A method of producing high strength steel sheet and formed articles fabricated from the sheet and containing about 0.01-0.3 free and uncombined atomic percent Ti, Nb or V as strengthening element, by hot rolling or hot rolling plus cold rolling the sheet within limited temperature ranges, annealing the rolled sheet or formed articles at a temperature of about 1275.degree.-1350.degree. F. to provide a (111) grain structure, nitriding the annealed sheet or formed article in an annealing furnace at a temperature of about 800.degree.-1250.degree. F. under fully developed laminar gas flow, and controlling the strengthening of the steel article as a function of steel composition, the nitriding gas composition, nitriding time, nitriding temperature, thickness of the steel sheet and depth of strengthening desired, in accordance with specified relationships, to provide a steel article having an 0.2% off-set yield strength after temper rolling of at least about 40 ksi and an r value in excess of about 1.

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 method for producing cast iron gears includes the steps of heating a blank composed of cast iron and having a teeth forming part to such a temperature that at least the teeth forming part is at least austenitized, and hot rolling the teeth forming part of the blank by pressing projecting teeth of a rolling machine against the teeth forming part which is in a hot state and within an austenitized range, while cooling the blank, thereby generating a teeth part in the teeth forming part of the blank. Hot rolling with a low plastic deformation resistance prevents lowering of strength due to the exposure of graphite particles of cast iron and occurrence of quenching cracks and rolling cracks, and improves gear accuracy.

Abstract: A method for forming a spring which can reduce variations in the surface hardness and the thickness of the hardened layer when the spring is nitrided. Before nitriding the spring, the thickness of an oxide film formed on the surface of the spring is reduced to 1.5 .mu.m or less by electropolishing or any other suitable means so that the residual stress of the spring will be -5 kgf/mm.sup.2 to 5 kgf/mm.sup.2 near its surface. With this arrangement, it is possible to increase the surface hardness and the thickness of the nitrided layer of the spring obtained by nitriding.

Abstract: A process for producing a coil spring comprises steps of: cold drawing a wire comprising: C in an amount of 0.55 to 0.75% by weight; Si in an amount of 1.00 to 2.50% by weight; at least two primary metals selected from the primary metal group consisting of: Mn in an amount of 0.30 to 1.5% by weight; Ni in an amount of 1.00 to 4.00% by weight; Cr in an amount of 0.50 to 2.50% by weight; Mo in an amount of 0.10 to 1.00% by weight; at least one secondary metal selected from the secondary metal group consisting of: V in an amount of 0.05 to 0.60% by weight; Nb in an amount of 0.05 to 0.60% by weight; and the balance of substantially Fe; oil quenching and tempering the wire; hot tempering the wire, thereby preparing the tempered wire whose tensile strength .sigma.b falls in the range of from 1370 to 1670 N/mm.sup.2 ; cold coiling; hardening and tempering; grinding; gas nitriding; high strength two-stage shot peening; and low temperature annealing the tempered wire.

Abstract: Loom components such as reed dents or weft brake lamellae that, during operation, are exposed to frictional abrasion by a moving weft thread, are made of cold rolled strip steel or of refined nitrided steels. The components are then exposed to a heat treatment at a temperature larger than 480.degree. C. for a duration of more than two hours, preferably up to 8 hours. A thermo-chemical treatment is performed simultaneously with the heat treatment to harden at least those surface areas of the components that in operation will be exposed to the frictional abrasion.

Abstract: Enrichment of surface and near surface regions of stainless steel components that nearly have their final shape with dissolved nitrogen at temperatures between 1000.degree. and 1200.degree. C. is provided. In this way, ferritic and martensitic structure portions in the surface zone are changed to austenite. By means of mixed crystal hardening, nitrogen increases the strength of the surface layer that is formed and that at the same time is characterized by the degree of toughness of the austenitic structure. The combination of strength and toughness leads to a significantly increased resistance to wear, especially wear due to impact, cavitation, and impingement of drops. In contrast to carbon, the resistance to corrosion of the surface layer is not adversely affected when nitrogen diffuses in, but rather is even further increased. The thermal treatment process is suitable for increasing the service life of rust proof components in flow-producing mechanisms.

Abstract: The present invention resides in a method for making an internal combustion engine intake valve. An iron aluminum alloy, in the form of a coil or bar stock, is provided. The alloy comprises 76.05 to 90.15 weight percent iron, 9 to 13.3 weight percent aluminum, 0.05 to 0.35 weight percent carbon, and 0.5 to 3 weight percent of a refractory metal, and/or 0.3 to 1.5 weight percent of titanium in combination with, or in place of, the refractory metal. The coil or bar stock is extruded to a poppet valve preform configuration at a heading temperature in the range of 800.degree. to 2,000.degree. F. and a true strain of about 0.5 to 2.2. The preform configuration is then headed to a pre-machined configuration while maintaining the head of such preform at an effective heading temperature up to 2,200.degree. F. said heading being carried out at a true strain of about 1.4 to 2.3.

Abstract: A method and article of manufacture of a coated iron based alloy. The method includes providing an iron based alloy substrate, depositing a silicon containing layer on the alloy surface while maintaining the alloy at a temperature of about 700.degree. C.-1200.degree. C. to diffuse silicon into the alloy surface and exposing the alloy surface to an ammonia atmosphere to form a silicon/oxygen/nitrogen containing protective layer on the iron based alloy.

Abstract: The surface layer of a hard austenitic stainless steel screw is formed as nitrided layer and then is covered by a plating coat or a resin coat to give properties such as shortening the boring time as well as heightening the surface hardness of the screw itself.

Abstract: In a process for producing a workpiece from sintered metal, especially from sintered iron, the latter is subjected, after sintering, to a steam treatment at temperatures below 500.degree. C., especially at 430.degree.-480.degree. C., at a steam partial pressure of from 20 to 80 mbar, especially from 30 to 50 mbar, to form an oxide layer on the surface, and to subsequent surface-hardening. Workpieces, especially internally geared wheels for starters, having a wear-resistant surface and, in the core, properties unchanged by the hardening are obtained.

Abstract: A hard nitrided layer is formed on austenitic stainless steel by holding the austenitic stainless steel in a heated condition under a fluorine- or fluoride-containing atmosphere and then nitriding it so that a close uniform nitriding layer can be formed, resulting the remarkable improvement in the surface hardness of the above-mentioned austenitic stainless steel. The temperature in the above-mentioned nitriding treatment is set below 450.degree. C. so that high anti-corrosion property, originally inherent in austenitic stainless steel, can be retained without deterioration.

Abstract: Method for the treatment of alloy steels and refractory metals such as Ti, Zr and Nb, especially for depassivation and subsequent thermochemical surface treatment in a process chamber (1, 2) under the action of pressure and temperature, wherein, in a first process step, a first gas or gas mixture from the group N.sub.2, H.sub.2 or NH.sub.3 is admitted for the depassivation into a process chamber (1), a pressure greater than 1 bar a and a temperature between 100.degree. C. and 1,000.degree. C. is established in the chamber (1), and in a second process step a second gas or gas mixture from the group of N-, C- or B-containing gases is admitted into a process chamber (1, 2) for the thermochemical surface treatment, and a temperature between 100.degree. C. and 1,000.degree. C. at a pressure greater than or equal to 1 bar a is established.

Abstract: A process for producing low-cost furnace atmospheres suitable for annealing and heat treating ferrous and nonferrous metals and alloys, brazing metals and ceramics, sealing glass to metal, and sintering metal and ceramic powders in a continuous furnace equipped with an ammonia dissociator from non-cryogenically produced nitrogen containing from 0.05 to 5.0% residual oxygen is presented. The disclosed process involves mixing non-cryogenically produced nitrogen with a pre-determined amount of a reducing gas such as hydrogen, ammonia, a C, H, and O containing hydrocarbon such as an alcohol, an ether, etc., or a mixture thereof, passing the mixture through an ammonia dissociator and converting the residual oxygen to an acceptable form such as moisture, carbon monoxide, carbon dioxide, or mixture thereof, and using the resultant gaseous mixture for annealing and heat treating ferrous and nonferrous metals and alloys, brazing metals and ceramics, sealing glass to metal, and sintering metal and ceramic powders.

Abstract: An improved process for deoxygenating non-cryogenically produced nitrogen with a hydrocarbon is disclosed. According to the process, non-cryogenically produced nitrogen stream containing residual oxygen impurity is 1) pre-heated, 2) mixed with a hydrocarbon, and 3) passed through a reactor packed with a platinum group of metal catalyst to reduce oxygen to very low levels by converting it to a mixture of carbon dioxide and moisture. The reactor effluent stream is optionally treated downstream to produce a nitrogen stream substantially free of moisture and carbon dioxide. The key features of the disclosed process include 1) pre-heating non-cryogenically produced nitrogen containing residual oxygen to a certain minimum temperature, 2) adding more than stoichiometric amount of a hydrocarbon to the pre-heated nitrogen stream, and 3) using a platinum group of metal catalyst to initiate and sustain the reaction between oxygen and hydrocarbon.

Abstract: The object of the present invention is to provide a piston ring which is free from occurrence of cracks on the nitrided layer and having enhanced abrasion resistance and fatigue strength, and to provide a process for manufacturing the piston ring. In the invention, a surface of the steel body is subjected to a two-stage nitriding treatment consisting of low-temperature nitriding and high-temperature nitriding. A white layer on the slidable surface along the inner periphery surface of a cylinder is removed, and a white layer on each of the upper and lower surfaces and the corner portions each being adjacent to the slidable surface is removed to have a thickness of not more than 5 .mu.m.

Abstract: A sliding member is sulphonitride by heating at 480.degree.-600.degree. C. in the presence of both 10-500 ppm of a hydrogen sulfide gas and a 20-70 vol % ammonia gas, or by a method which comprises performing a primary heat treatment on the sliding member at 450.degree.-540.degree. C. in the presence of 50-200 ppm of a hydrogen sulfide gas and a 10-70 vol % ammonia gas, then ceasing the supply of the ammonia gas, slowly reducing the temperature to a level of 200.degree.-350.degree. C., and performing a secondary heat treatment at that temperature level. By the either method, the sliding member having a FeS.sub.2 on its topmost surface can be obtained.

Abstract: A process for producing low-cost furnace atmospheres suitable for annealing and heat treating ferrous and non-ferrous metals and alloys, brazing metals and ceramics, sealing glass to metals, and sintering non-ferrous metal and ceramic powders from non-cryogenically produced nitrogen containing from 0.05 to 5.0% residual oxygen is presented. The disclosed process involves 1) mixing non-cryogenically produced nitrogen with a predetermined amount of dissociated ammonia, 2) passing the mixture through a low-pressure drop catalytic reactor, 3) converting the residual oxygen to an acceptable form such as moisture and reducing the residual oxygen level to below about 10 ppm, and 4) using the resultant gaseous mixture for annealing and heat treating ferrous and non-ferrous metals and alloys, brazing metals and ceramics, sealing glass to metals, and sintering non-ferrous metal and ceramic powders.

Abstract: A method of forming a wear-resistant coating for internal combustion engine component parts which allows the part to remain dimensionally stable under severe engine operating conditions is provided. The coating is formed by a two step method. First, the engine part is coated with chromium to form a chromium base layer. Second, the chromium coated part is subjected to a reactive gas plasma in a reaction chamber at an elevated temperature and under an applied electrical potential. The gas of the plasma reacts with the chromium to form the wear-resistant layer. Preferably, the reactive gas is nitrogen which reacts with the chromium to form a chromium nitride surface layer on the chromium base layer.

Abstract: Very low-pore, thick nitride cases may be obtained in a short time during a gas nitriding process in accordance with the invention. This process includes nitriding in a gaseous mixture containing about 5 to 95% by volume ammonia and about 95 to 5% by volume nitrogen. The nitriding process is most preferably carried out at essentially a constant pressure above about 0.2 MPa.

Abstract: A method for manufacturing a shadow mask is used for color television picture tubes and the like. The surface of a shadow mask body, made of Fe-Ni type alloy, is ion-nitriding processed so as to make the most of the low thermal expansion property inherent in the alloy. The result is that the color purity degradation caused by the thermal expansion at temperature increases of the mask, and by the resonance of the mask itself, can be prevented, thereby realizing a shadow mask serving to render a highly refined CRT.

Abstract: Steel is nitrided first by treating the steel to be nitrided with NF.sub.3 at elevated temperatures to form a fluorinated layer on the steel, and then the steel is nitrided by heating in a nitriding atmosphere.

Abstract: This invention makes a furnace body divide into two, a pretreating chamber and a nitriding chamber by an opening and closing center wall. After pretreating works to be treated in the pretreating chamber, the opening and closing center wall is opened and the pretreated works are transferred to the nitriding chamber to nitride them. Treatment gas can be saved largely compared with the case that the nitriding is conducted after pretreating works in a furnace which has only a nitriding chamber.