There is provided a surface treatment method in which a processing gas is brought in contact with a heated processing object made of steel, an element in the processing gas is solid-solutionized, and thus a surface treatment is performed on the processing object. The processing object is heated to a heating temperature in a vicinity of a processing temperature at which the surface treatment is performed by heating an atmosphere in which the processing object is disposed. The surface treatment is performed by bringing the processing gas in contact with a surface of the processing object while the processing object which is heated is directly heated to the processing temperature.

There is provided a surface treatment method in which a processing gas is brought in contact with a heated processing object made of steel, an element in the processing gas is solid-solutionized, and thus a surface treatment is performed on the processing object. The processing object is heated to a heating temperature in a vicinity of a processing temperature at which the surface treatment is performed by heating an atmosphere in which the processing object is disposed. The surface treatment is performed by bringing the processing gas in contact with a surface of the processing object while the processing object which is heated is directly heated to the processing temperature.

Provided is steel for nitrocarburizing with excellent surface fatigue strength. The steel has a nitride compound layer with a thickness of 5.0 μm to 30.0 μm and a hardened layer in an order from a steel surface to steel inside, where a thickness of a porous layer on an outermost surface of the compound layer is 3.0 μm or less and 40.0% or less of a compound layer's thickness, the hardened layer has hardness of HV600 or more, HV400 or more and HV250 or more at 50 μm inward from the steel surface, from the steel surface to the steel inside of 400 μm, and from the steel surface to the steel inside of 600 μm, respectively, an unhardened portion excluding the compound and hardened layers has a predetermined chemical composition, and the hardened layer has a chemical composition with a higher N content than the unhardened portion.

Provided is steel for nitrocarburizing with excellent surface fatigue strength. The steel has a nitride compound layer with a thickness of 5.0 μm to 30.0 μm and a hardened layer in an order from a steel surface to steel inside, where a thickness of a porous layer on an outermost surface of the compound layer is 3.0 μm or less and 40.0% or less of a compound layer's thickness, the hardened layer has hardness of HV600 or more, HV400 or more and HV250 or more at 50 μm inward from the steel surface, from the steel surface to the steel inside of 400 μm, and from the steel surface to the steel inside of 600 μm, respectively, an unhardened portion excluding the compound and hardened layers has a predetermined chemical composition, and the hardened layer has a chemical composition with a higher N content than the unhardened portion.

The present invention relates to a method of hardening slides of a perforating press comprising providing a steel beam; hardening of the steel beam in a vacuum furnace; tempering the steel beam twice; first straightening of the steel beam at a temperature of 20° C. ± 10° C.; milling of an at least partially continuous sawtooth profile, along a longitudinal direction of the steel beam, on a first side of the steel beam; wherein, after milling the at least partially continuous sawtooth profile on the first side of the steel beam, a second side of the steel beam, lying opposite the first side, is hardened by means of induction currents, after which the steel beam is again tempered twice and after which the steel beam is straightened a second time at a temperature of 20° C. ± 10° C. The invention also relates to a slide for a perforating press hardened according to the method.

A ductile iron composition including, by weight: about 3.4% to about 4.0% Si; about 3.0% to about 3.5% C; about 0.5% to about 1.0% Cr; about 0.02% to about 0.05% Mo; up to about 0.01% S; up to about 0.5% Mn; and balance iron and incidental impurities.

The composition has a a ferritic body center cubic microstructure and has a graphite nodule density of greater than 100 per mm.sup.2. A method for forming a ductile iron composition is also disclosed.

A method and apparatus for manufacturing a part. The part may be positioned in a chamber. The part may be comprised of a metal and may be a positioned part. A gas containing nitrogen may be sent into the chamber. An electromagnetic field may be generated in the chamber with the gas. The electromagnetic field may heat a portion of the metal in the positioned part to a temperature from about 60 percent to about 99 percent of the melting point of the metal such that the portion of the metal has a desired hardness. The portion of the metal may extend from a surface of the positioned part to a selected depth from the surface.

A method and apparatus for manufacturing a part. The part may be positioned in a chamber. The part may be comprised of a metal and may be a positioned part. A gas containing nitrogen may be sent into the chamber. An electromagnetic field may be generated in the chamber with the gas. The electromagnetic field may heat a portion of the metal in the positioned part to a temperature from about 60 percent to about 99 percent of the melting point of the metal such that the portion of the metal has a desired hardness. The portion of the metal may extend from a surface of the positioned part to a selected depth from the surface.

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 IFe.sub.4N (111) of a (111) crystal plane of Fe.sub.4N and X-ray diffraction peak intensity IFe.sub.3N (111) of a (111) crystal plane of Fe.sub.3N, which are measured on a surface of the nitrided steel member by X-ray diffraction, an intensity ratio expressed by IFe.sub.4N (111)/{IFe.sub.4N (111)+IFe.sub.3N (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 μm.

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 IFe.sub.4N (111) of a (111) crystal plane of Fe.sub.4N and X-ray diffraction peak intensity IFe.sub.3N (111) of a (111) crystal plane of Fe.sub.3N, which are measured on a surface of the nitrided steel member by X-ray diffraction, an intensity ratio expressed by IFe.sub.4N (111)/{IFe.sub.4N (111)+IFe.sub.3N (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 μm.