A method of manufacturing a brake disc of heterogeneous materials, may include a disc device and a hub device formed in a cast-bonding manner using different materials, includes performing a first casting for casting the disc device using a grey cast-iron material, performing a preparation step by placing the disc device in a casting mold as an insert, performing a second casting for preparing a brake disc cast product by injecting molten aluminum alloy into the casting mold and casting the hub device to be cast-bonded to the disc device, and performing an oxynitriding process for forming an oxynitride layer by smoothing a surface of the brake disc cast product and performing heat treatment in a gaseous atmosphere at a temperature ranging from 425 to 500 C.

A surface treatment layer for a titanium-containing substrate includes a disordered metal oxide lattice having metal nitride compounds doped in the disordered metal oxide lattice. A method of surface treating a metal substrate includes introducing oxygen to a titanium-containing substrate to thereby form an oxide layer within the titanium-containing substrate, and, after the step of introducing oxygen, introducing nitrogen to the titanium-containing substrate to thereby modify the oxide layer to form a surface treatment layer.

A method for manufacturing a forged article, capable of improving the durability of a die for forging is provided. The method, includes forging a steel material, by using a die, by spraying or applying a water-soluble polymer lubricant containing 0.01 to 0.98 mass % of a water-soluble sulfate onto a working surface of the die, the die being made of a raw material having a constituent composition of by mass %, of 0.4 to 0.7% of C, 1.0% or less of Si, 1.0% or less of Mn, 4.0 to 6.0% of Cr, 2.0 to 4.0% of (Mo+?W), 0.5 to 2.5% of (V+Nb), 0 to 1.0% of Ni, 0 to 5.0% of Co, 0.02% or less of N, and a remnant composed of Fe and impurities, and having hardness of 55 to 60 HRC, and the die including a nitrided layer or a nitrosulfidized layer on the working surface thereof.

The present invention relates to a case hardened component of a titanium alloy, the component having a diffusion zone of a thickness of at least 50 ltl, as calculated from the surface of the component, the diffusion zone comprising oxygen and carbon in solid solution and having a distinct phase of a carbo-oxide compound having the composition TiO.sub.xC.sub.1-x, wherein x is a number in the range of 0.01 to 0.99, which diffusion zone has a microhardness of at least 800 HV0.025 and which carbo-oxide compound has a microhardness of at least 1200 HV0.025. In another aspect the invention relates to a method of producing the case hardened component. In a further aspect the invention relates to a method of oxidising a component of a Group IV metal.

The present invention relates to a case hardened component of a titanium alloy, the component having a diffusion zone of a thickness of at least 50 ltl, as calculated from the surface of the component, the diffusion zone comprising oxygen and carbon in solid solution and having a distinct phase of a carbo-oxide compound having the composition TiO.sub.xC.sub.1-x, wherein x is a number in the range of 0.01 to 0.99, which diffusion zone has a microhardness of at least 800 HV0.025 and which carbo-oxide compound has a microhardness of at least 1200 HV0.025. In another aspect the invention relates to a method of producing the case hardened component. In a further aspect the invention relates to a method of oxidising a component of a Group IV metal.

A method of mechanically processing a metallic material component is provided whereby alloying, carburizing, nitriding and boriding can be performed using a friction stir processing tool. This method for mechanically processing metallic material surfaces is cost effective, efficient and does not require specialized equipment.

A number of variations may include a ferritic nitrocarburized part comprising steel, wherein the ferritic nitrocarburized steel has a tensile strength exceeding the parent steel material and sufficient ductility, bendability, and flangeability to support subsequent flanging and press-fitting of bushings. Exact strength increases and bendability will be dependent on exact process and alloy combinations.

A number of variations may include a ferritic nitrocarburized part comprising steel, wherein the ferritic nitrocarburized steel has a tensile strength exceeding the parent steel material and sufficient ductility, bendability, and flangeability to support subsequent flanging and press-fitting of bushings. Exact strength increases and bendability will be dependent on exact process and alloy combinations.

A method for providing a surface finish to a metal part includes both diffusion hardening a metal surface to form a diffusion-hardened layer, and oxidizing the diffusion-hardened layer to create an oxide coating thereon. The diffusion-hardened layer can be harder than an internal region of the metal part and might be ceramic, and the oxide coating can have a color that is different from the metal or ceramic, the color being unachievable only by diffusion hardening or only by oxidizing. The metal can be titanium or titanium alloy, the diffusion hardening can include carburizing or nitriding, and the oxidizing can include electrochemical oxidization. The oxide layer thickness can be controlled via the amount of voltage applied during oxidation, with the oxide coating color being a function of thickness. An enhanced hardness profile can extend to a depth of at least 20 microns below the top of the oxide coating.

A method for providing a surface finish to a metal part includes both diffusion hardening a metal surface to form a diffusion-hardened layer, and oxidizing the diffusion-hardened layer to create an oxide coating thereon. The diffusion-hardened layer can be harder than an internal region of the metal part and might be ceramic, and the oxide coating can have a color that is different from the metal or ceramic, the color being unachievable only by diffusion hardening or only by oxidizing. The metal can be titanium or titanium alloy, the diffusion hardening can include carburizing or nitriding, and the oxidizing can include electrochemical oxidization. The oxide layer thickness can be controlled via the amount of voltage applied during oxidation, with the oxide coating color being a function of thickness. An enhanced hardness profile can extend to a depth of at least 20 microns below the top of the oxide coating.