Abstract: An epsilon iron nitride surface layer of high surface wear resistance is formed on a steel component by gas nitriding or nitrocarburizing and, according to the invention, includes the preliminary step of heating the component to the nitriding temperature in an atmosphere which is inert to the metal of the component.

Abstract: A method is disclosed for subjecting a steel component made of a non-alloy or fine grained steel to a hardening treatment. An epsilon iron nitride surface layer of high surface area resistance is formed on the steel component by gas nitriding or nitrocarburizing and includes the preliminary step of heating the component to the nitriding temperature in an atmosphere which is inert to the metal of the component.

Abstract: Thin metal articles of pre-determined shape are given a first treatment to provide a hardened surface and a second treatment to correct distortion caused by the hardening treatment. The hardening is provided an epsilon nitride layer and the corrective treatment is a heat treatment at 150.degree. to 600.degree. C., which will correct the distortion without reducing the hardness of the epsilon nitride layer.

Abstract: A component formed of interstitial free steel is heated in a gaseous atmosphere containing 15% by volume of a nitrogen doner, e.g. ammonia, at about 500.degree. C. to about 740.degree. C. for about 30 minutes to about 4 hours to form an epsilon iron nitride surface layer, and a layer of nitrides of trace alloying elements below the surface layer.

Abstract: A non-alloy steel component is nitrocarburized at 550.degree. to 720.degree. C. for up to 4 hours in a nitriding gaseous atmosphere e.g. ammonia or ammonia and endothermic or exothermic gas, and is thus exposed to air or other oxidizing atmosphere for 2 to 120 seconds to form an oxide-rich layer thereon before being quenched into an oil/water emulsion, degreased and a tack-free wax coating applied. Alternatively, the component may be cooled in air or other oxidizing atmosphere and then wax coated or it may be cooled in a non-oxidizing atmosphere and then reheated to provide the oxide-rich surface layer before being cooled again and wax coated. As a further alternative, the component may be cooled, lapped to a surface roughness of not more than 0.2 micrometers Ra, reheated to oxidize and then quenched. These techniques give a good corrosion resistance to the component.

Abstract: To impart good salt spray corrosion resistance to alloy steel components, such components are gas nitrocarburized at 550.degree. C. to 800.degree. C. to produce an epsilon layer, oxidized to produce an Fe.sub.3 O.sub.4 layer not more than 1 micrometer thick, quenched into an oil/water emulsion, degreased and then wax coated. The steel components may be surface finished after nitrocarburizing.A carburizing, carbonitriding or neutral atmosphere heat treatment may be effected prior to nitrocarburizing heat treatment with both heat treatments being effected at above the pearlite to austenite transformation temperature.

Abstract: A non-alloy steel component is nitrocarburized at 550.degree. to 720.degree. C. for up to 4 hours in a nitriding gaseous atmosphere eg. ammonia or ammonia and endothermic or exothermic gas, and is thus exposed to air or other oxidizing atmosphere for 2 to 120 seconds to form an oxide-rich layer thereon before being quenched into an oil/water emulsion, degreased and a tack-free wax coating applied. Alternatively, the component may be cooled in air or other oxidizing atmosphere and then wax coated or it may be cooled in a non-oxidizing atmosphere and then reheated to provide the oxide-rich surface layer before being cooled again and wax coated. As a further alternative, the component may be cooled, lapped to a surface roughness of not more than 0.2 micrometers Ra, reheated to oxidize and then quenched. These techniques give a good corrosion resistance to the component.