There is provided an Ni-base super alloy which is used for airplane engines and gas turbines for power generation and has favorable mechanical properties at high temperature. The Ni-base super alloy contains 0.001 to 0.1 mass % of C, 1.0 to 4.0 mass % of Al, 2.0 to 4.5 mass % of Ti, 12.0 to 18.0 mass % of Cr, 11.1 to 18.0 mass % of Co, 1.2 to 12.0 mass % of Fe, 1.5 to 6.5 mass % of Mo, 0.5 to 6.0 mass % of W, 0.1 to 3.0 mass % of Nb, 0.001 to 0.05 mass % of B, 0.001 to 0.1 mass % of Zr, and Ni and impurities as a remainder.

A method for heat treating a metal tube or pipe is provided to perform heat treatment in such a manner that metal tubes or pipes (1) to be accommodated in a heat treatment furnace are laid down on a plurality of cross beams (22) arranged along a longitudinal direction of the metal tubes or pipes with the distance between adjacent cross beams being in a range of 200 to 2500 mm. This makes it possible to inhibit bending and scratches of the metal tubes or pipes without causing discoloration and deterioration of the manufacturing efficiency for the metal tubes or pipes. When the metal tubes or pipes (1) are laid down on the cross beams (22), spacers may be interposed between the metal tubes or pipes (1) and the cross beams (22) on which they are laid down.

A nickel-based superalloy with an increased oxidation resistance, power, and welding method, is provided. As a result of the addition of hafnium, no precipitation phases occur in the nickel-based superalloy and the proportions of chromium (Cr) and aluminium (Al) lead to a slightly reduced y′-content, thus achieving good oxidation resistance and weldability.

The present invention relates to an Ni-based superalloy for hot forging, containing, in terms of % by mass, C: more than 0.001% and less than 0.100%, Cr: 11% or more and less than 19%, Co: more than 5% and less than 25%, Fe: 0.1% or more and less than 4.0%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Nb: 0.3% or more and less than 4.0%, Al: more than 3.0% and less than 5.0%, Ti: more than 1.0% and less than 3.0%, and Ta: 0.01% or more and less than 2.0%, with the balance being unavoidable impurities and Ni, in which the component composition satisfies the following two relationships: 3.5≦([Ti]+[Nb]+[Ta])/[Al]×10<6.5 and 9.5≦[Al]+[Ti]+[Nb]+[Ta]<13.0.

The present invention relates to an Ni-based superalloy for hot forging, containing, in terms of % by mass, C: more than 0.001% and less than 0.100%, Cr: 11% or more and less than 19%, Co: more than 5% and less than 25%, Fe: 0.1% or more and less than 4.0%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Nb: 2.0% or more and less than 4.0%, Al: more than 3.0% and less than 5.0%, and Ti: more than 1.0% and less than 3.0%, with the balance being unavoidable impurities and Ni, in which the component composition satisfies the following two relationships: 3.5≦([Ti]+[Nb])/[Al]×10<6.5 and 9.5≦[Al]+[Ti]+[Nb]<13.0.

Properties and performance of weld material between metals in a weldment is controlled by modifying one or more of the nitrogen content and the carbon content to produce carbide (e.g. MC-type), nitride and/or complex carbide/nitride (e.g. MX-type) type precipitates. Fusion welding includes (i) adjusting shield gas composition to increase nitrogen/carbon gas and nitride/carbide species, (ii) adjusting composition of nitrogen/carbon in materials that participate in molten welding processes, (iii) direct addition of nitrides/carbides (e.g. powder form), controlled addition of nitride/carbide forming elements (e.g. Ti, Al), or addition of elements that increase/impede solubility of nitrogen/carbon or nitride/carbide promoting elements (e.g. Mn), and (iv) other processes, such as use of fluxes and additive materials. Weld materials have improved resistance to different cracking mechanisms (e.g., hot cracking mechanisms and solid state cracking mechanisms) and improved tensile related mechanical properties.

The present invention provides a hot-forgeable Ni-based superalloy excellent in high temperature strength, including, in terms of % by mass: C: more than 0.001% and less than 0.100%, Cr: 11.0% or more and less than 19.0%, Co: 0.5% or more and less than 22.0%, Fe: 0.5% or more and less than 10.0%, Si: less than 0.1%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Mo+½W: 2.5% or more and less than 5.5%, S: 0.010% or less, Nb: 0.3% or more and less than 2.0%, Al: more than 3.00% and less than 6.50%, and Ti: 0.20% or more and less than 2.49%, with the balance being Ni and unavoidable impurities, in which (Ti/Al)×10 is 0.2 or more and less than 4.0 in terms of atomic ratio, and in which Al+Ti+Nb is 8.5% or more and less than 13.0% in terms of atomic %.

The present invention relates to a turbine wheel of an automotive turbocharger, including a Ni-based alloy having a composition which contains, in terms of mass %: C: 0.08 to 0.20%; Mn: 0.25% or less; Si: 0.01 to 0.50%; Cr: 12.0 to 14.0%; Mo: 3.80 to 5.20%; Nb+Ta: 1.80 to 2.80%; Ti: 0.50 to 1.00%; Al: 5.50 to 6.50%; B: 0.005 to 0.015%; Zr: 0.05 to 0.15%; and Fe: 0.01 to 2.5%, with the remainder being Ni and unavoidable impurities, in which the turbine wheel includes a wing part and a shaft part, and a size of γ′ phase in each site of from a tip of the wing part to the shaft part is structure-controlled so as to fall within a range of from 0.4 to 0.8 μm.

A nickel base super alloy or blade alloy having Ni as a main constituent and the following elements or portions in wt %: Fe: 2 to 8, Al: 6.1 to 6.8, Cr: 12.5 to 15, W: 1.5 to 4.5, Ta: 2.5 to 5.5, Hf: 1.2 to 2, C: 0.03 to 0.13, B: 0.005 to 0.02, Zr: 0.005 to 0.02, and Si: 0.005 to 0.02.

A nickel based superalloy, including: Chromium (Cr) 12.0%-14.0%, Molybdenum (Mo) 1.5%-3.0%, Tungsten (W) 2.5%-4.5%, Aluminum (Al) 4.0%-5.0%, Titanium (Ti) 1.8%-2.8%, Niobium (Nb) 1.5%-3.5%, Hafnium (Hf) 0.8%-1.8%, Carbon (C) 0.03%-0.13%, Boron (B) 0.005%-0.025%, Silicon (Si) 0.005%-0.05%, and optionally: Cobalt (Co) 0.0%-10.0%, Tantalum (Ta) 0.0%-3.0%, Zirconium (Zr) 0.0%-0.03%, especially remainder Nickel.