Abstract: An Ni base forged alloy is easy to make hot forging and miniaturization of crystal grains while excellent high-temperature strength and segregation property are compatible. The Ni base forged alloy has solid solution temperature of a precipitation strengthening phase lower than or equal to 970° C., difference in the solid solution temperature between a ?-phase and the precipitation strength phase larger than or equal to 50° C., Al of 0.5 to 1.0%, Cr of 17 to 21%, Fe of 17 to 19%, Nb of 4.5 to 5.5%, Ti of 0.8 to 1.3%, W of 3.0 to 6.0%, B of 0.001 to 0.03%, C of 0.001 to 0.1% and Mo of 1.0% or less in mass percentage [%] and remainder made of Ni and inevitable impurities.

Abstract: A turbine rotor includes a high- and low-temperature side rotor base materials. The high- and low-temperature materials include concavities and grooves. The turbine rotor has an enclosed space formed by the concavity of the high- and low-temperature materials being disposed opposingly, and a gap formed by the grooves of the high- and low-temperature materials being disposed opposingly. The turbine rotor contains a buildup welding section formed between the high- and low-temperature materials, which has the same composition as that of the high- or low-temperature material, and has a penetration bead on the enclosed space side, and the gap contains a weld metal filled therein. Thus, a stable penetration bead can be formed in a dissimilar material welded rotor combining two kinds of alloy materials with different thermal properties, and then generation of a non-welded portion of a butting section that becomes a start point of fracture can be suppressed.

Abstract: A nickel (Ni) based alloy for forging includes: 0.001 to 0.1 wt. % of carbon (C); 12 to 23 wt. % of chromium (Cr); 3.5 to 5.0 wt. % of aluminum (Al); 5 to 12 combined wt. % of tungsten (W) and molybdenum (Mo) in which the Mo content is 5 wt. % or less; a negligible small amount of titanium (Ti), tantalate (Ta) and niobium (Nb); and the balance of Ni and inevitable impurities.

Abstract: A high-temperature piping product is configured from a plurality of primary pipe members and a welding material. The primary pipe members are each made from an Ni-based forged alloy containing: Ni, Al, and at least one of Mo and W. The total content of the Mo and the W being 3-8 mass %. The Ni-based forged alloy exhibiting a ??-phase dissolution temperature of from 920 to 970° C., and the ?? phase being precipitated in 30 volume % or more in a temperature range of from 700 to 800° C. The welding material is made from an Ni-based cast alloy having a cast structure formed by welding. The Ni-based cast alloy containing: Ni, Al, and at least one of Mo and W, the total content of the Mo and the W being 9-15 mass %, the Ni-based cast alloy exhibiting a ??-phase dissolution temperature of from 850 to 900° C.

Abstract: The Ni based forged alloy has a composition containing, on the basis of mass percent, Al: 0.5 to 1.0%, Cr: 17 to 21%, Fe: 17 to 19%, Nb: 4.5 to 5.5%, Ti: 0.8 to 1.3%, W: 3.0 to 6.0%, B: 0.001 to 0.03%, C: 0.001 to 0.015%, and Mo: 1.0% or less, the balance being Ni and inevitable impurities. The alloy includes carbide grains of the contained elements. The carbide grains have an average grain diameter of 20 ?m or less. Thus, a Ni based forged alloy is provided which is excellent in high-temperature fatigue property and has a moderate macrosegregation property.

Abstract: To provide, in producing a large product through casting, a Ni-based alloy with a composition that minimizes variations in strength at different locations even when the solidification rate becomes slow and the amount of micro segregation increases. The Ni-based casting alloy of the present invention has a composition of, in mass %, 0.001% to 0.1% C, 15% to 23% Cr, 0% to 11.5% Mo, 3% to 18% W, 5 or less % Fe, 10 or less % Co, 0.4 or less % Ti, 0.4 or less % Al, and Nb and Ta (where 0.5%?Nb+Ta?4.15%), in which 7%?Mo+1/2W?13% is satisfied, and the composition also contains inevitable impurities and Ni.

Abstract: A heat resistant alloy member that maintains the creep strength and improves the fatigue characteristics is provided. The heat resistant alloy member according to the present invention includes a recrystallized structure layer including finer grains on the surface of the member than those inside of the member. The recrystallized structure layer is formed by forming a stirred layer by giving processing strain to the surface of the member using a friction stir processing, and applying recrystallization heat treatment to the stirred layer for recrystallization.

Abstract: It is an objective of the invention to provide a steam turbine rotor of which a rotor shaft is made of a low-cost heat resistant ferritic steel and that can withstand high main steam temperatures of about 650° C. There is provided a steam turbine rotor comprising: a rotor shaft made of a heat resistant ferritic steel such as a 12-Cr steel; and a rotor blade made of a Ti—Al alloy, wherein the Ti—Al alloy includes: from 38 to 45 atomic % of Al; from 0.5 to 2 atomic % of V; from 2 to 6 atomic % of Cr and/or Mo; and the balance being Ti and incidental impurities.

Abstract: There are provided: an Ni-based alloy member including a ?? phase precipitation with 36 to 60 volume % and exhibiting a high durable temperature and good cold workability; a method for producing the member; an Ni-based alloy product to be used as a precursor of the member; and a method for producing the product. The Ni-based alloy product has a two-phase structure composed of a ? phase and a ?? phase being incoherent to the ? phase, the incoherent ?? phase being present at a ratio of 20 volume % or higher. The Ni-based alloy member produced by cold working the Ni-based alloy product and subsequently by conducting heat treatment comprises a ? phase and a ?? phase being coherent to the ? phase, the coherent ?? phase being present at a ratio of 36 to 60 volume %, and has a predetermined shape.

Abstract: The invention provides a Ni—Fe-based alloy which is preferable for a welding of a joint between different materials such as a steel material and a Ni-based alloy, and a rotor for a steam turbine which is manufactured by using the same. The invention employs a Ni—Fe-based alloy including Cr: 14 to 18%, Al: 1.0 to 2.5%, Mo+W: 2.5 to 5.0%, C: 0.01 to 0.10%, B: 0.001 to 0.03%, and Fe: 15 to 20%, in mass, in which the remaining portion is constructed by an unavoidable impurity and Ni, as a welding metal. As a result, it is possible to provide a rotor for a steam turbine which can hold down a reduction of a ductility and a toughness generated in the case of welding the different materials, and is excellent in a strength and the ductility.

Abstract: To provide a manufacturing process of a Ni based superalloy and a member of the Ni based superalloy which achieves both of excellent workability in a manufacturing step of the Ni based superalloy of the precipitation strengthening type which contains much amount of the gamma prime phase and excellent high temperature strength of the Ni based superalloy. The manufacturing process of a Ni based superalloy includes a step for softening the Ni based superalloy and improving the workability, in which the step for softening the Ni based superalloy and improving the workability is a step for precipitating the gamma prime phase that is incoherent with a gamma phase that is a matrix by 20 vol % or more.

Abstract: It is an objective of the invention to provide a precipitation-hardening martensitic stainless steel having a far better balance between a high mechanical strength and a high toughness than conventional ones as well as having good corrosion resistance properties. There is provided a precipitation-hardening martensitic stainless steel throughout which precipitates of intermetallic compounds are dispersed, the martensitic stainless steel including: 0.1 mass % or less of C; 11 to 13 mass % of Cr; 7.5 to 11 mass % of Ni; 0.9 to 1.7 mass % of Al; 0.85 to 1.35 mass % of Mo; 1.75 to 2.75 mass % of W; and the balance including Fe and inevitable impurities, in which “[Mo content]+0.5×[W content]” is from 1.9 mass % to 2.5 mass %, and “[Mo content]/[W content]” is from 0.4 to 0.6.

Abstract: A nickel (Ni) based alloy for forging includes: 0.001 to 0.1 wt. % of carbon (C); 12 to 23 wt. % of chromium (Cr); 3.5 to 5.0 wt. % of aluminum (Al); 5 to 12 combined wt. % of tungsten (W) and molybdenum (Mo) in which the Mo content is 5 wt. % or less; a negligible small amount of titanium (Ti), tantalate (Ta) and niobium (Nb); and the balance of Ni and inevitable impurities.

Abstract: A nickel (Ni) based alloy for forging includes: 0.001 to 0.1 wt. % of carbon (C); 12 to 23 wt. % of chromium (Cr); 3.5 to 5.0 wt. % of aluminum (Al); 5 to 12 combined wt. % of tungsten (W) and molybdenum (Mo) in which the Mo content is 5 wt. % or less; a negligible small amount of titanium (Ti), tantalate (Ta) and niobium (Nb); and the balance of Ni and inevitable impurities.

Abstract: The Ni based forged alloy has a composition containing, on the basis of mass percent, Al: 0.5 to 1.0%, Cr: 17 to 21%, Fe: 17 to 19%, Nb: 4.5 to 5.5%, Ti: 0.8 to 1.3%, W: 3.0 to 6.0%, B: 0.001 to 0.03%, C: 0.001 to 0.015%, and Mo: 1.0% or less, the balance being Ni and inevitable impurities. The alloy includes carbide grains of the contained elements. The carbide grains have an average grain diameter of 20 ?m or less. Thus, a Ni based forged alloy is provided which is excellent in high-temperature fatigue property and has a moderate macrosegregation property.

Abstract: Disclosed are a high-strength Ni-base alloy, a method of producing the Ni-base alloy, and a method of recovering a member made of a degraded Ni-base alloy. It contains not more than 0.1 wt % C, not more than 50 wt % Fe, not more than 30 wt % Cr, Ti, and at least one of Nb and Al. It has been strengthened by precipitates of a ?? phase (Ni3Al) and/or a ?? phase (Ni3Nb). It contains also a ? phase (Ni3Ti) which is thermodynamically stable in a temperature range of 800° C. to 900° C. When observed a cross-section of the Ni-base alloy, a plurality of nodes exist along each segment connecting two meeting points each of which point is defined by adjacent three crystal grains, and precipitates of the ?? phase and/or the ?? phase in each of crystal grains of the Ni-base alloy have an average particle size of not more than 100 nm.

Abstract: This method is a method for manufacturing a gas turbine blade, including: producing a gas turbine blade having a cooling pass inside thereof; and partially coating an inner surface of the cooling pass with Al. The step of partially coating an inner surface of the cooling pass with Al further including: a first step of specifying a temperature range which satisfies both of oxidation resistance and fatigue strength and the temperature distribution of the inner surface of the cooling pass based on an examination result or result of a numerical analysis; a second step of setting an Al-coating-applying portion of the inner surface of the cooling pass as the temperature range specified at the first step; and a third step of applying Al coating only into the set Al-coating-applying portion.

Abstract: The present invention provides, in a ?? phase precipitation strengthening type Ni-base alloy, an alloy excellent in heat treatment capability and weldability and suitable for joint with a ferritic steel. Further, the present invention provides a welded turbine rotor having the strength, ductility, and toughness simultaneously over the whole welded structure when a precipitation strengthening type Ni-base alloy having a heatproof temperature of 675° C. or higher is joined to a ferritic steel. A Ni-base alloy according to the present invention contains cobalt, chromium, aluminum, carbon, boron, and at least either tungsten or molybdenum with the remainder being nickel and inevitable impurities, having an alloy composition including 12 to 25 percent by mass of Co, 10 to 18 percent by mass of Cr, 2.0 to 3.6 percent by mass of Al, 0.01 to 0.15 percent by mass of C, 0.001 to 0.03 percent by mass of B, the total amount of tungsten and molybdenum being 5.0 to 10 percent by mass.

Abstract: It is an objective of the invention to provide a Ni-based forged alloy having good large ingot formability and good hot formability as well as high mechanical strength at high temperature. There is provided a Ni-based forged alloy comprising: 0.001 to 0.1 mass % of C; 0.001 to 0.01 mass % of B; 16 to 22 mass % of Cr; 0.5 to 1.5 mass % of Al; 0.1 to 6.0 mass % of W; 3.5 to 5.5 mass % of Nb; 0.8 to 3.0 mass % of Ti; 16 to 20 mass % of Fe; 2.0 mass % or less of Mo; and the balance including Ni and unavoidable impurities, in which: a segregation parameter Ps defined by a formula of “Ps (mass %) =1.05×[Al concentration (mass %)]+0.6×[Ti concentration (mass %)]?0.8×[Nb concentration (mass %)]?0.3×[Mo concentration (mass %)]” satisfies a relationship of “Ps??3.0 mass %”; and a total amount of W and Mo is 1.75 atomic % or less.

Abstract: In a gas turbine blade where a part of the ?? phase precipitation strengthened type Ni-based alloy base material is composed of a weld metal, the weld metal is a Ni-based alloy containing Ta from 4.8 to 5.3 wt. %, Cr from 18 to 23 wt. %, Co from 12 to 17 wt. %, W from 14 to 18 wt. %, C from 0.03 to 0.1 wt. %, Mo from 1 to 2 wt. %, and Al of 1 wt. % or less, in which the oxygen content is 0 to 30 ppm, the Ti content from 0 to 0.1 wt. %, and the Re content from 0 to 0.5 wt. %. A blade base metal is manufactured by the step of stripping, the step of solution heat treatment where the ?? phase is dissolved again, the step of welding in an inert gas chamber by a TIG method using a welding wire where the weld metal can be obtained, the step of HIP treatment at 1100° C. to 1150° C., and the step of an aging treatment at 835° C. to 855° C.