The present invention relates to a steel composition carburizable and/or nitritable, comprising, in percentages by weight of the total composition: Carbon: 0.05-0.40, preferably 0.10-0.30; Chromium: 2.50-5.00, preferably 3.00-4.50; Molybdenum: 4.00-6.00; Tungsten: 0.01-1.80, preferably 0.02-1.50; Vanadium: 1.00-3.00, preferably 1.50-2.50; Nickel: 2.00-4.00; Cobalt: 2.00-8.00, preferably 3.00-7.00; Iron: balance as well as the inevitable impurities, optionally further comprising one or more of the following elements: Niobium: 2.00; Nitrogen: 0.50, preferably 0.20; Silicon: 0.70, preferably 0.05-0.50; Manganese: 0.70, preferably 0.05-0.50; Aluminum: 0.15, preferably 0.10; the combined niobium+vanadium content being in the range 1.00-3.50; and the carbon+nitrogen content being in the range 0.05-0.50. It further relates to the method of production thereof, the steel blank obtained and a mechanical device comprising the latter.

In a hot isostatic pressing (HIP) method, the component to be treated, affected by imperfections, like porosity, cracks and cavities in its structure, is placed into a container together with non-metallic material in form of powder or grains having size greater than the porosity and the cracks and imperfections of the component. During the HIP process, the non-metallic material presses on the whole surface of the embedded component in order to generate a combination of temperature and forces capable to reduce defects, embedded and not embedded, in the component itself. The component is not contaminated during the process thus allowing easily removal of the non-metallic material by a simple operation of mechanical cleaning or chemical washing.

A valve in an embodiment includes: a valve box in which valve box seat portions are provided; and a valve element on which valve element seat portions are provided. One of the valve box seat portion and the valve element seat portion is formed of a build-up material of a Co-based alloy and the other of the valve box seat portion and the valve element seat portion is formed of a build-up material of an Fe-based alloy. Then, a Vickers hardness of the build-up material of the Co-based alloy is larger than a Vickers hardness of the build-up material of the Fe-based alloy and a difference in the Vickers hardness between the build-up material of the Co-based alloy and the build-up material of the Fe-based alloy is HV50 or more.

Method of producing a tube of duplex stainless steel is disclosed. The steel comprises the following composition, in weight %: C max 0.03, Si max 1.0, Mn max 1.5, P max 0.05, S max 0.03, Cr 24-26, Ni 6-8, Mo 3.0-4.0, N 0.24-0.32. The method comprises steps of: forming a tube of the duplex stainless steel, cold working the tube obtained from the step of forming a tube, and soft annealing the tube after the step of cold working by subjecting the tube to a temperature, T, within a range of 500-750 C. for a time period, t, of 0.5-5 minutes.

A method of welding a superalloy component includes the following sequential steps. A welding step for welding a cavity using a filler metal in an inert atmosphere, where the cavity is located in the component. A covering step for covering the filler metal and a portion of the component with a weld filler layer in the inert atmosphere. The weld filler layer has a greater ductility than material comprising the component and/or material comprising the filler metal. A second covering step for covering the weld filler layer with a braze material, and subsequently performing a brazing operation. A heat treating step heat treats the component.

The present invention relates to a steel composition carburizable and/or nitritable, comprising, in percentages by weight of the total composition: Carbon: 0.05-0.40, preferably 0.10-0.30; Chromium: 2.50-5.00, preferably 3.00-4.50; Molybdenum: 4.00-6.00; Tungsten: 0.01-1.80, preferably 0.02-1.50; Vanadium: 1.00-3.00, preferably 1.50-2.50; Nickel: 2.00-4.00; Cobalt: 2.00-8.00, preferably 3.00-7.00; Iron: balance as well as the inevitable impurities, optionally further comprising one or more of the following elements: Niobium: 2.00; Nitrogen: 0.50, preferably 0.20; Silicon: 0.70, preferably 0.05-0.50; Manganese: 0.70, preferably 0.05-0.50; Aluminum: 0.15, preferably 0.10; the combined niobium+vanadium content being in the range 1.00-3.50; and the carbon+nitrogen content being in the range 0.05-0.50.

It further relates to the method of production thereof, the steel blank obtained and a mechanical device comprising the latter.

The inventive concept relates to method for manufacturing a metal based component comprising at least one protrusion. The method comprises: providing a metal based substrate comprising a surface having at least one cavity; providing a metal based protrusion element comprising a first portion and a second portion, wherein said first portion has a shape that conforms to a shape of the cavity; arranging the first portion of the protrusion element in said cavity such that at least the second portion of the protrusion element protrudes at least 5 mm from a surface of the metal based substrate, to form a substrate comprising a protrusion; placing said substrate comprising a protrusion in a canister such that a void is formed between the canister and the surface of the substrate comprising the protrusion; filling at least a portion of the void with a diamond powder such that the surface of the substrate comprising the protrusion is covered by the inert filler material; removing gas from the interface between said diamond powder and said substrate comprising the protrusion; subjecting said substrate comprising the protrusion to a hot isostatic pressing process for a predetermined time at a predetermined pressure and a predetermined temperature such that said substrate and protrusion element bond metallurgically to each other to form said metal based component comprising said at least one protrusion; removing at least a part of said diamond powder from said metal based component having a protrusion, wherein a melting point of the diamond powder at said predetermined temperature is higher than said predetermined temperature.

A carburisable steel alloy suitable for bearing components comprising, in percent by weight: C 0.05-0.5 wt. % Cr 2.5-5.0 wt. %, Mo 4-6 wt. %, W 2-4.5 wt. %, V 1-3 wt. %, Ni 2-4 wt. %, Co 2-8 wt. %, optionally one or more of the following elements: Nb 0-2 wt. % N 0-0.5 wt. % Si 0-0.7 wt. %, Mn 0-0.7 wt. %, Al 0-0.1 5 wt. %, wherein the combined amount of Nb+V is within the range 1-3.5 wt. %, the combined amount of C+N is within the range 0.05-0.5 wt. %, the balance being Fe and unavoidable impurities.

A method of manufacturing an austenitic iron alloy comprising placing austenitic iron alloy powder in a can, evacuating air and other gases from the can, supplying nitrogen gas into the can, sealing the can and then hot isostatically pressing the austenitic iron alloy powder in the can to diffuse the nitrogen into the austenitic iron alloy powder and to produce a nitrogen enriched austenitic iron alloy bar and removing the can from the nitrogen enriched austenitic iron alloy bar.

A strain-hardenable stainless steel alloy includes hard secondary phases dispersed in an austenitic primary phase, the alloy including 0.3-0.6% nitrogen by weight.