A method for treating a part made of ferrous metal includes a nitriding operation forming on the part a combination layer having a thickness of between 5 and 30 μm, and a diffusion region, arranged beneath and in contact with the combination layer, having a thickness of between 100 μm and 500 μm. The method also includes an operation of quenching the part by high-frequency induction, over an induction depth that is greater than or equal to 0.5 mm, thereby hardening the part. The resulting part has a surface hardness greater than or equal to 50 HRC, a hardness of the combination layer greater than or equal to 400 HV0.05, and a hardness of the part greater than or equal to 500 HV0.05 at a depth of 500 μm. The high-frequency induction quenching operation is performed without the application of a protective film on the part prior to the induction quenching operation.

A braking band having an annular band body arranged around a rotation axis and made of one of gray cast iron, steel, aluminum or alloys thereof, has at least one braking surface having an activated band body portion for increasing adhesive capacity of at least one protective surface coating placed on the surface of the activated band body portion and having at least one material with elevated resistance to abrasion. The activated band body portion is arranged on the surface of the annular band body to form an outermost layer of the braking band with the at least one protective surface coating and has a rough profile having at least one channel delimited by at least one pair of projections, extending along a path at least partially surrounding the rotation axis and having a channel bottom and a first channel side forming an acute angle with the channel bottom and an opposite second channel side forming an obtuse angle with the channel bottom.

A method for heat treating a steel component, the method comprising steps of: (a) carbonitriding the steel component and (b) ferritically nitrocarburizing the steel component.

A method for heat treating a steel component, the method comprising steps of: (a) carbonitriding the steel component and (b) ferritically nitrocarburizing the steel component.

A method and a system for cooling treating metal parts exiting a nitriding/nitrocarburizing treatment in molten salt baths, comprising a cooling chamber in direct relation with a nitriding/nitrocarburizing station for receiving parts therefrom; a gaseous nitrogen feeding unit connected to the cooling chamber and configured to create an inert atmosphere within the cooling chamber; and a screened transfer path between the nitriding/nitrocarburizing station and the cooling chamber; wherein after exiting molten salt baths of the nitriding/nitrocarburizing station, the treated parts are transferred to the cooling chamber through the screened transfer path, and cooled therein to a minimum temperature above a temperature at which salts congeal.

A method and a system for cooling treating metal parts exiting a nitriding/nitrocarburizing treatment in molten salt baths, comprising a cooling chamber in direct relation with a nitriding/nitrocarburizing station for receiving parts therefrom; a gaseous nitrogen feeding unit connected to the cooling chamber and configured to create an inert atmosphere within the cooling chamber; and a screened transfer path between the nitriding/nitrocarburizing station and the cooling chamber; wherein after exiting molten salt baths of the nitriding/nitrocarburizing station, the treated parts are transferred to the cooling chamber through the screened transfer path, and cooled therein to a minimum temperature above a temperature at which salts congeal.

A track pin for a track chain assembly includes a body made from a steel alloy. The steel alloy has a composition comprising iron, a nitride-forming element, a carbide-forming element, and silicon. The composition of the steel alloy comprises at least 0.5 percent by weight of silicon. The body includes a compound layer on an exterior surface thereof. The compound layer includes at least one of Fe.sub.2-3(C,N) microstructures and Fe.sub.4N microstructures formed therein by ferritic nitro-carburizing.

A track pin for a track chain assembly includes a body made from a steel alloy. The steel alloy has a composition comprising iron, a nitride-forming element, a carbide-forming element, and silicon. The composition of the steel alloy comprises at least 0.5 percent by weight of silicon. The body includes a compound layer on an exterior surface thereof. The compound layer includes at least one of Fe.sub.2-3(C,N) microstructures and Fe.sub.4N microstructures formed therein by ferritic nitro-carburizing.

A rotary positive displacement pump (1) comprises a pump enclosure (10) and at least one rotating member (20). The pump enclosure (10) has an inlet (12) and an outlet (14). The rotating member (20) is arranged for, when being rotated, causing a transfer of a liquid from the inlet (12) to the outlet (14). The rotary positive displacement pump (1) has internal sliding surfaces (16, 24, 26, 32, 34) that during operation are exposed to the liquid and are exposed to a sliding contact relative to other internal sliding surfaces (16, 24, 26, 32, 34) of the rotary positive displacement pump (1). At least a part of the internal sliding surfaces (16, 24, 26, 32, 34) has a surface region composed by a nitrided or nitrocarburized steel intercalated with a solid lubricant. A method for manufacturing a rotary positive displacement pump is also disclosed.

A sliding spline shaft device of the present invention includes a male spline and a female spline that is fitted to the male spline in an axially slidable manner, and at least one of the splines has a surface processed layer. The surface processed layer includes an undercoat layer, an intermediate layer containing phosphate, and a topcoat layer containing solid lubricant, in this order. The undercoat layer contains iron nitride and/or iron carbide. Thus, the surface of a base material has high hardness. As a result, microscopic deformation of the sliding surface is reduced, and increase in a real contact area is suppressed, whereby stick-slip is prevented.