Abstract: An embodiment of the invention describes a method of treating an article to improve its corrosion resistance. The method includes the step of nitriding the article in a cyanide-free nitriding bath to obtain a nitrided article, heating the nitrided article in an atmosphere having nitrogen and carbon-carburizing to obtain a nitrided oxidised article. Further, in certain embodiments, the oxidised nitrided article may be coated with a metallic layer. The oxidised nitrided article with the metallic coating has improved corrosion resistance.

Abstract: An embodiment of the invention describes a method of treating an article to improve its corrosion resistance. The method includes the step of nitriding the article in a cyanide-free nitriding bath to obtain a nitrided article, heating the nitrided article in an atmosphere having nitrogen and carbon-carburizing to obtain a nitrided oxidised article. Further, in certain embodiments, the oxidised nitrided article may be coated with a metallic layer. The oxidised nitrided article with the metallic coating has improved corrosion resistance.

Abstract: Steel for nitrocarburizing includes, by mass %, C: 0% to less than 0.15%; Si: 0.01% to 1.00%; Mn: 0.01% to 1.00%; S: 0.0001% to 0.050%; Al: 0.0001% to 0.050%; Ti: more than 0.50% to 1.50%; N: 0.0005% to 0.0100%; and the balance consisting of Fe and inevitable impurities, in which P is limited to 0.050% or less; O is limited to 0.0060% or less; and the amount of Ti [Ti %], the amount of C [C %], the amount of N [N %], and the amount of S [S %] satisfy 0.48<[Ti %]?47.9×([C %]/12+[N %]/14+[S %]/32)?1.20.

Abstract: A manufacturing method includes, cutting out a plurality of rings, polishing the rings, adjusting the plurality of rings so that they exhibit circumferential lengths respectively predetermined for them, nitriding the plurality of rings, and assembling in order to layer the plurality of rings into a multi-layered ring; wherein after the rings are cut out from the pipe, each of them is polished one by one so that their order is not changed; in nitriding, they are subjected to a nitriding process in a state where they are set in a jig in order to keep their order; and in assembling, the rings are assembled so that rings that were parts originally adjacent to each other in a state of the pipe become layers that are adjacent to each other in the multi-layered ring.

Abstract: A method for manufacturing an endless metal belt used in a belt-type continuously variable transmission, wherein a stress-relief heat treatment is performed after the circumference of a ring body has been adjusted, and aging/nitridation is performed after the stress-relief heat treatment.

Abstract: A process for manufacturing a bellows, made of austenitic high-grade steel with high compressive strength and fatigue strength, forms a single-layer or multilayer sleeve into a bellows with hydraulic forming. The pressure resistance and fatigue strength are improved by the bellows being cleaned after the forming and by the bellows being exposed to a surrounding area containing carbon and/or nitrogen atoms at temperatures between 100° C. and 400° C., preferably 200° C. to 320° C. With this a hardening of the bellows takes place by means of the diffusing in of carbon and/or nitrogen atoms. A bellows made of austenitic high-grade steel with one or more layers created in this manner has the edge layer hardened by the incorporation of carbon and/or nitrogen atoms up to a hardening depth of at least 5% of the wall thickness.

Abstract: A molten-salt bath for nitriding mechanical steel parts, essentially consisting of the following (the contents being expressed in wt %): 25 to 60 wt % of alkali-metal chlorides; 10 to 40 wt % of alkali-metal carbonates; 20 to 50 wt % of alkali-metal cyanates; and a maximum of 3 wt % of cyanide ions (formed during the use of the bath), wherein the total of the contents is 100 wt %. Preferably, the bath contains: 25 to 30 wt % of sodium cyanate; 25 to 30 wt % of sodium carbonate and lithium carbonate; 40 to 50 wt % of potassium chlorides; and a maximum of 3 wt % of cyanide ions (formed during the use of the bath), the total of the contents being 100 wt %.

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: The invention relates to a crankshaft member having high fatigue strength and good bending correctability, and its method of manufacture. The steel made crankshaft member mainly consists of a two-phase structure of ferrite and perlite. The steel includes C, Ni, Mn, and Cr as required elements and Si, Cu, Mo, Ti, V, Nb, Ca, and S as optional elements that may be included, in the amounts of C within the range of 0.20 to 0.50 wt %, Si within the range of 0 to 0.6 wt %, Mn within the range of 0.5 to 1.5 wt %, Cu within the range of 0 to 0.7 wt %, Ni within the range of 0.05 to 1.5 wt %, Cr within the range of 0.05 to 0.45 wt %, and Mo within the range of 0 to 0.5 wt % to satisfy the condition 115?70C+8Si+23Mn+11Cu+128Cr+83Mo?50. A portion of the member surface is provided at least with a hard nitride layer having an average hardness within the range of 300 to 450 HV. Lamellar spacing of the perlite is 0.3 ?m or less.

Abstract: A molten-salt bath for nitriding mechanical steel parts, essentially consisting of the following (the contents being expressed in wt %): 25 to 60 wt % of alkali-metal chlorides; 10 to 40 wt % of alkali-metal carbonates; 20 to 50 wt % of alkali-metal cyanates; and a maximum of 3 wt % of cyanide ions (formed during the use of the bath), wherein the total of the contents is 100 wt %. Preferably, the bath contains: 25 to 30 wt % of sodium cyanate; 25 to 30 wt % of sodium carbonate and lithium carbonate; 40 to 50 wt % of potassium chlorides; and a maximum of 3 wt % of cyanide ions (formed during the use of the bath), the total of the contents being 100 wt %.

Abstract: A method for hardening running surfaces of roller bearing components, in particular outer bearing rings. In order to provide the edge area (functional layer) of the roller bearing components with a deep layer which is particularly hard and resistant to corrosion, the roller bearing component undergoes nitration for a long period of time at a temperature of between 450 and 650° C. for at least 25 hours. During treatment no carburizing and subsequently no quenching takes place.

Abstract: A metal composite for use in electrochemical devices is disclosed. The metal composite comprises a stainless steel interior component and a deposited nitrided metal exterior layer, wherein the nitrided exterior layer has lower electric contact resistance and greater corrosion resistance than the stainless steel interior component. A bipolar plate made of such metal composite and methods of producing the metal composite and bipolar plate are also disclosed.

Abstract: A cost effective system, method and apparatus adapted to provide a nitride layer on stainless steel used for the manufacture of consumer electronic products. In addition to providing a durable, hard surface that is both scratch and impact resistant, the nitride layer allows for the natural surface color and texture of the underlying stainless steel to remain visible to the user. It is this natural surface color and texture of the stainless steel that adds to the aesthetically pleasing appearance of the consumer electronic product thereby enhancing the user's overall experience.

Abstract: A cost effective system, method and apparatus adapted to provide a nitride layer on stainless steel used for the manufacture of consumer electronic products. In addition to providing a durable, hard surface that is both scratch and impact resistant, the nitride layer allows for the natural surface color and texture of the underlying stainless steel to remain visible to the user. It is this natural surface color and texture of the stainless steel that adds to the aesthetically pleasing appearance of the consumer electronic product thereby enhancing the user's overall experience.

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

Abstract: Disclosed is a method of producing maraging steel, which includes producing a consumable electrode for vacuum remelting; and subjecting the consumable electrode to the vacuum remelting. The consumable electrode contains not less 5 ppm Mg. Disclosed is also a maraging steel containing, by mass %, at least, from more than zero to less than 10 ppm Mg, less than 10 ppm oxygen, and less than 15 ppm nitrogen. The steel contains also nitride inclusions having a maximum length of not more than 15 ?m and oxide inclusions having a maximum length of not more than 20 ?m. Regarding the oxide inclusions, a content rate of spinel form inclusions having a length of not less than 10 ?m to a total content of the spinel form inclusions having a length of not less than 10 ?m and alumina inclusions having a length of not less than 10 ?m exceeds 0.33 (i.e. 33%).

Abstract: A method for diffusing titanium and nitride into a base material having a coating thereon using conventional surface treatments or coatings. The method generally includes the steps of providing a base material having a coating thereon; providing a salt bath which includes sodium dioxide and a salt selected from the group consisting of sodium cyanate and potassium cyanate; dispersing metallic titanium formed by electrolysis of a titanium compound in the bath; heating the salt bath to a temperature ranging from about 430° C. to about 670° C.; and soaking the base material in the salt bath for a time of from about 10 minutes to about 24 hours. In accordance with another aspect of the present invention, titanium and nitride may be diffused into a base material without a coating. The treated base material may further be treated with conventional surface treatments or coatings.

Abstract: Provided is a method for nitriding a metal in a salt bath by using a non-cyanide salt and a nitrided metal manufactured using the same. The method includes the steps of: immerging at least one salt selected from the group consisting of KNO3, KNO2, Ca(NO3)2, NaNO3 and NaNO2 into the salt bath; melting the salt by heating and maintaining the molten salt at a predetermined temperature; and submerging the metal in the salt bath. Nitriding in non-cyanide salts, such as potassium nitrate (KNO3), potassium nitrite (KNO2), sodium nitrate (NaNO3), sodium nitrite (NaNO2), calcium nitrate (Ca(NO3)2) and their mixtures, is capable of solving an environmental pollution problem and reducing a cost. Also, the method is capable of increasing nitrided depth of the metal two to six times compared to conventional nitriding methods. As a result, the method can be carried out in various application fields.

Abstract: A new nitriding process by using a salt bath to produce iron and steel parts having excellent abrasion resistance and corrosion resistance includes forming an iron lithium complex oxide layer at the outermost surface of the iron part by immersing the iron and steel parts in a salt bath containing cationic component of Li, Na and K and anionic components of CNO?and CO32?, where hydroxide compound selected from lithium hydroxide, sodium hydroxide and potassium hydroxide are added to the salt bath. Materials being in a hydrated state or in a free water containing state can be used for preparation or replenishing of the salt bath. Moistened air of (1×10?2 kg·H2O)/(1 kg dry air) can be used for mixing the salt bath. Containing ratio of Li, Na, K is preferable where a solidifying temperature of the mixture of carbonates of Li, Na, K in that ratio is lower than 500° C.

Abstract: A method for producing a steel material having a high fatigue strength and given a uniform residual stress by a rapid treatment. A marageing steel is subjected to a cold plastic working to have a predetermined dimension, to a solution treatment for 60 minutes or more at a temperature of 750 to 800° C., and to an aging.

Abstract: The present invention concerns a method for generating nanostructures in order to obtain in an area on the surface of a metal piece (10) a nanostructured layer of defined thickness, characterized in that it comprises: a step for projecting onto an impact point in the area of the surface of the piece (10) to be treated, for a given duration, at a given speed and at variable incidences at the same impact point, a given quantity of perfectly spherical balls (22) of given dimensions, reused continuously during the projection; repetition of the preceding step with a shift of the impact point so that the impact points as a group cover the entire surface of the piece to be treated; a step for treatment by diffusion of chemical compounds into the nanostructured layer generated during the step for implementing the method for generating nanostructures.

Abstract: Hard metal particles having hardness which is lower than the hardness of a nitrided outermost layer of a spring and in the range of Hv 500 to 800 and a diameter of 500 to 900 &mgr;m are protected against the nitrided surface of the spring at a velocity of 40 to 90 m/sec to prevent generation of a microcrack in the surface layer and provide a compression residual stress comparatively deep inside the spring. Against the resultant spring surface, a number of fine metal particles having a mean diameter of all particles of 80 &mgr;m or less, a mean diameter of each particle in the range between 10 &mgr;m inclusive and less than 100 &mgr;m, a spherical or near spherical shape with no square portions, a specific gravity of 7.0 to 9.0, and hardness which falls in the range between Hv 600 and Hv 1100 inclusive and is equal to or less than the hardness of the outermost surface layer of the spring after nitriding, at a velocity of 50 to 190 m/sec.

Abstract: A composition for nitrocarburizing stainless steel parts and a method for producing a nitride or hard case on such parts using the composition, are provided. The composition includes alkali metal cyanate and alkali metal carbonate, wherein the cyanate ion is present in a weight percentage of greater than 45% and less than 55.2%. The composition is fused and maintained between about 750° F. and about 950° F. depending upon the type of stainless steel to be treated. The workpiece is immersed in the fused bath and left in until a satisfactory compound layer or case is formed. With austenitic stainless steel, the piece is immersed from about four hours to about six hours at temperatures between about 750° F. and about 950° F., preferably between 750° F. and 850° F. to maintain corrosion resistance.

Abstract: A composition for nitrocarburizing stainless steel parts and a method for producing a nitride or hard case on such parts using the composition, are provided. The composition includes alkali metal cyanate and alkali metal carbonate, wherein the cyanate ion is present in a weight percentage of greater than 45% and less than 55.2%. The composition is fused and maintained between about 750° F. and about 950° F. depending upon the type of stainless steel to be treated. The workpiece is immersed in the fused bath and left in until a satisfactory compound layer or case is formed. With austenitic stainless steel, the piece is immersed from about four hours to about six hours at temperatures between about 750° F. and about 950° F., preferably between 750° F. and 850° F. to maintain corrosion resistance. With 400 series stainless steel, increased corrosion resistance is achieved by immersion for between four and six hours at 950° F.

Abstract: A laminated ring for use as a belt in transmitting power in a continuously variable transmission is produced by welding opposite ends of a sheet of maraging steel to produce a plurality of rings, and rolling said rings to a predetermined length. The rings are nitrided in a salt-bath nitriding process by dipping the rings in a molten salt containing 38-46% of CNO− and 1-2% of CN− and heated to a temperature in the range from 480 to 530° C., for a period of time ranging from 10 to 25 minutes. The nitrided rings are finally stacked into a laminated ring.

Abstract: A cylindrical drum, which comprises a sheet of maraging steel with welded opposite ends, is severed into a plurality of rings of predetermined width, and the rings are rolled to a predetermined length, after which circumferential lengths of the rings are corrected. The rings are aged by placing the rings into an aging chamber, heating the aging chamber to a predetermined aging temperature, and keeping the rings at the predetermined aging temperature for a predetermined period of time. Thereafter, the rings are nitrided by transferring the rings from the aging chamber into a nitriding chamber which is disposed independently of the aging chamber and has been heated to a predetermined nitriding temperature, while maintaining the rings at the aging temperature, keeping the rings at the nitriding temperature in an atmosphere containing at least an ammonia gas for a predetermined period of time, and cooling the rings.

Abstract: A cylindrical drum is prepared by welding opposite ends of a thin sheet of maraging steel. A first solution treatment is effected on the cylindrical drum, and then the cylindrical drum is severed into a plurality of rings each having a predetermined width. After the rings are rolled, a second solution treatment is effected on the rings which have been rolled, and then the circumferential length of each of the rings is corrected. The rings are aged and nitrided, and then stacked into a laminated ring. The first solution treatment and the second solution treatment are effected using the same heating furnace in the same atmosphere in the same temperature range.

Abstract: A rotary drill bit is manufactured by a method including the step of forming at least a portion of the bit body from a precipitation hardening alloy, and brazing cutters to the bit body by a heating and cooling cycle during which the bit body is first heated to a temperature sufficient to melt the brazing material and is then cooled to room temperature, the heating and cooling brazing cycle being controlled in a manner so as also to effect precipitation hardening of the alloy from which the bit body is formed. In the case where the bit body is formed from solid infiltrated matrix material around a solid preformed mandrel, the heating and cooling cycle of the matrix forming process may also be controlled in a manner to effect precipitation hardening of the alloy from which the mandrel is formed.

Abstract: A method for nitriding a metallic base material at low temperatures in a salt bath containing electrolyzed titanium metal. A nitride coating of exceptional depth and hardness is obtained in a very short operating time due to the rapid nitriding process. The method is applicable to steel, titanium, aluminum and alloys thereof.

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: 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: A method of surface treating a metallic machine tool element includes heating the element prior to insertion of the metal element into a nitrating salt bath for the purpose of both hardening the element and improving the resilience of portions required to be flexed in use.

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 of nitriding steel which comprises reacting the steel surface with nitrogen so as to form a hard nitrided layer, and, prior to nitriding, holding steel under a gas atmosphere containing fluorine compound gas or fluorine gas and also containing air of 0.5 to 20 volume % of the total or oxygen gas of 0.1 to 4 volume % of the total with heating, whereby occurrence of uneven nitriding is prevented and at the same time savings in consumption of expensive fluorine- or fluoride-containing gas can be realized.

Abstract: In subjecting a steel workpiece to nitriding by glow discharge, formation of brittle nitrogen compound is restrained and the surface hardened layer with a nitrogen diffusion layer of high toughness is obtained by making the gas atmospheric condition the gas mixing ratio of N.sub.2 :H.sub.2 =1:2-40. By mixing Ar gas in the above gas atmospheric condition additionally, glow width is adjusted and glow discharge is allowed to enter into narrow concaves at the surface of a workpiece.

Abstract: A hard wear-resistant and corrosion- and oxidation-resistant stainless steel article is made by precision machining a work piece of approximately the size and shape of the desired article, then subjecting the resulting cold worked article to ion bombardment until the article is nitrided to a depth of about 0.002 inch, and finally subjecting the nitrided article to an atmosphere of argon and nitrogen and oxygen until the resulting ion bombardment has penetrated to a depth in the article surface of about 0.0001 inch.