Abstract: A rotor, a steam turbine having a rotor, and a method of producing a rotor are disclosed. The rotor disclosed includes a shaft high pressure section. The high pressure section includes a first high pressure section, a second high pressure section, the second high pressure section being joined to the first pressure section, and a third high pressure section, the third high pressure section being joined to the second high pressure section. At least a portion of the second high pressure section is formed of a high-chromium alloy steel comprising 0.1-1.2 wt % of Mn, up to 1.5 wt % of Ni, 8.0-15.0 wt % of Cr, up to 4.0 wt % of Co, 0.5-3.0 wt % of Mo, 0.05-1.0 wt % of V, 0.02-0.5 wt % of Nb, 0.005-0.15 wt % of N, up to 0.04 wt % of B, up to 3.0 wt % of W, and balance Fe and incidental impurities.

Abstract: Shrouded turbine blisks and methods of manufacturing same are provided. A shrouded turbine blisk includes a central disk portion including an axis of rotation, an inner rim, a plurality of airfoils that extends radially outwardly from the inner rim; and a shroud integrally coupled to each of the plurality of airfoils. The shroud includes a plurality of circumferentially-arranged arcuate shroud segments defined at least in part by gaps positioned between adjacent shroud segments. The central disk portion, the inner rim, the plurality of airfoils, and the shroud are defined from a single billet of blisk material.

Abstract: A method of making a turbine rotor is disclosed. The method includes forming a last stage disk preform having a disk axis, the preform having a rotor face and an opposed shaft face, the rotor face having a circumferential, axially-extending rotor rib protruding therefrom, the shaft face having a circumferential, axially-extending shaft rib protruding therefrom, the disk preform comprising a disk preform material. The method also includes joining the rotor rib to a rotor preform to form a rotor joint, the rotor preform comprising a rotor preform material. The method further includes joining the shaft rib to a shaft to form a shaft joint, the shaft comprising a shaft material, wherein the disk preform material is different than the rotor preform material and the shaft material.

Abstract: A method of heat treating a superalloy article is disclosed. The method includes hot-working an article comprising an superalloy to produce a hot-worked microstructure throughout the article; solution treating the article at a temperature and for a time sufficient to form a partially recrystallized warm-worked microstructure throughout the article; and cooling the article. The method also includes precipitation aging the article at a first precipitation aging temperature of about 1300° F. to about 1400° F. for a first duration of about 4 hours to about 12 hours; cooling the article to a second precipitation aging temperature; precipitation aging the article at a second precipitation aging temperature of about 1150° F. to about 1200° F. for a second duration of about 4 hours to about 12 hours; and cooling the article from the second precipitation aging temperature to an ambient temperature.

Abstract: A method of forming a dual alloy member for joining two dissimilar materials includes selecting a first material and a second material that is different from the first material, metallurgically combining the first and second materials, forming the first and second materials into a preform using a hot work metal working process, shaping the preform into using another metal working process, and machining the perform to obtain a predetermined shape.

Abstract: Disclosed herein is a method of treating a component comprising solution treating the component for a period of about 4 to about 10 hours at a temperature of about 1750 to about 1850° F.; cooling the component to a temperature of about 1490 to about 1520° F. at an average rate of 1° F./min to about 25° F./min; stabilizing the component at about 1450 to about 1520° F. for a period of from about 1 to about 10 hours; cooling the component to room temperature; precipitation aging the component by heating the component to a first precipitation aging temperature of about 1275 to about 1375° F. for about 3 to about 15 hours; cooling the component at an average rate of 50 to about 150° F./hour to a second precipitation aging temperature of about 1100 to about 1200° F. for a time period of about 2 to about 15 hours; and cooling the component.

Abstract: Disclosed herein is a method of treating a component comprising solution treating the component for a period of about 4 to about 10 hours at a temperature of about 1750 to about 1850°F.; cooling the component to a temperature of about 1580 to about 1650°F. at an average rate of 1°F./min to about 25°F./min; stabilizing the component at about 1580 to about 1650°F. for a period of about 1 to about 10 hours; cooling the component to room temperature; precipitation aging the component at a first precipitation aging temperature of about 1275 to about 1375°F. for about 3 to about 15 hours; cooling the component at an average rate of 50 to about 150°F./hour to a second precipitation aging temperature of about 1100 to about 1200°F. for a time period of about 2 to about 15 hours; and cooling the component.

Abstract: A large volume, cast superalloy pressure containment vessel is disclosed. The vessel includes a hollow body portion having a volume of at least about 4 cubic feet and a substantially porosity-free cast microstructure. The containment vessel configured for operation at an operating temperature of at least about 1,200° F. and an operating pressure of at least about 1,500 psi. A large volume, cast superalloy article is also disclosed. The article has a volume of at least about 4 cubic feet and a substantially porosity-free cast microstructure, the article configured for operation at an operating temperature of at least about 1,400° F.

Abstract: A process and alloy for producing a turbine blade whose properties enable the blade to operate within a steam turbine at maximum operating temperatures of greater than 1300° F. (about 705° C.). The process includes casting the blade from a gamma prime-strengthened nickel-base superalloy having a composition of, by weight, 14.25-15.75% cobalt, 14.0-15.25% chromium, 4.0-4.6% aluminum, 3.0-3.7% titanium, 3.9-4.5% molybdenum, 0.05-0.09% carbon, 0.012-0.020% boron, maximum 0.5% iron, maximum 0.2% silicon, maximum 0.15% manganese, maximum 0.04% zirconium, maximum 0.015% sulfur, maximum 0.1% copper, balance nickel and incidental impurities, and an electron vacancy number of 2.32 maximum. The casting then undergoes a high temperature solution heat treatment to promote resistance to hold-time cracking. The blade exhibits a combination of yield strength, stress rupture properties, environmental resistance, and cost in steam turbine applications to 1400° F. (about 760° C.).

Abstract: A treatment for improving resistance to stress corrosion cracking (SCC) and a treated component are disclosed. A surface of a relatively high tensile strength component that includes a superalloy material is heated to a temperature at which softening occurs. The surface is then cooled in a controlled manner so as to maintain a reduced tensile strength at the surface that improves resistance to SCC while keeping a relatively high tensile strength in the remainder of the component.

Abstract: A multi-material rotor, a super-critical steam turbine having a multi-material rotor, and a method of producing a multi-material rotor are disclosed. The rotor includes a shaft high temperature section having a first end and a second end. The shaft high temperature section is made up of at least three different materials.

Abstract: A sectioned rotor is disclosed that includes a high temperature section. The high temperature section includes a first high temperature material section, a second high temperature material section; and a sectioned high temperature material section formed of a plurality of high temperature material subsection components. The sectioned high temperature material section is joined to the first high temperature material section and the second high temperature section. The plurality of the high temperature subsection components are independently formed of a nickel-based superalloy. A steam turbine having a sectioned rotor and a method for manufacturing a sectioned rotor are also disclosed.

Abstract: A rotor, a steam turbine having a rotor, and a method of producing a rotor are disclosed. The rotor disclosed includes a shaft high pressure section. The high pressure section includes a first high pressure section, a second high pressure section, the second high pressure section being joined to the first pressure section, and a third high pressure section, the third high pressure section being joined to the second high pressure section. At least a portion of the second high pressure section is formed of a high-chromium alloy steel comprising 0.1-1.2 wt % of Mn, up to 1.5 wt % of Ni, 8.0-15.0 wt % of Cr, up to 4.0 wt % of Co, 0.5-3.0 wt % of Mo, 0.05-1.0 wt % of V, 0.02-0.5 wt % of Cb, 0.005-0.15 wt % of N, up to 0.04 wt % of B, up to 3.0 wt % of W, and balance Fe and incidental impurities.

Abstract: A detection process is disclosed. The detection process includes applying a load to a preselected portion of an article. The applying of the load permits visually indiscernible cracks in the preselected portion of the article to be detected. The treated article includes a preselected portion having treated visually indiscernible cracks. The treated visually indiscernible cracks are substantially devoid of damage due to the treatment of the visually indiscernible cracks.

Abstract: A method of making a multiple alloy, multi-section welded turbine rotor includes providing a forged multiple alloy rotor section having an integral microstructure, the rotor section comprising a first alloy having a first alloy composition and second alloy having a second alloy composition, a first weld face comprising the first alloy on a first end and an a second weld face comprising the second alloy on an opposed second end. The method also includes providing a first rotor section comprising the first alloy composition and a second rotor section comprising the second alloy composition. The method also includes welding the first rotor section to the first weld face and welding the second rotor section to the second weld face.

Abstract: A method of making a turbine rotor is disclosed. The method includes forming a last stage disk preform having a disk axis, the preform having a rotor face and an opposed shaft face, the rotor face having a circumferential, axially-extending rotor rib protruding therefrom, the shaft face having a circumferential, axially-extending shaft rib protruding therefrom, the disk preform comprising a disk preform material. The method also includes joining the rotor rib to a rotor preform to form a rotor joint, the rotor preform comprising a rotor preform material. The method further includes joining the shaft rib to a shaft to form a shaft joint, the shaft comprising a shaft material, wherein the disk preform material is different than the rotor preform material and the shaft material.

Abstract: A method of heat treating an Ni-base superalloy article is disclosed. The method includes hot-working an article comprising an NiCrMoNbTi superalloy comprising, in weight percent, at least about 55 Ni to produce a hot-worked microstructure; solution treating the article at a temperature of about 1600° F. to about 1750° F. for about 1 to about 12 hours to form a partially recrystallized warm-worked microstructure; and cooling the article. The method also includes precipitation aging the article at a first precipitation aging temperature of about 1300° F. to about 1400° F. for a first duration of about 4 hours to about 12 hours; cooling the article to a second precipitation aging temperature; precipitation aging the article at a second precipitation aging temperature of about 1150° F. to about 1200° F. for a second duration of about 4 hours to about 12 hours; and cooling the article from the second precipitation aging temperature to an ambient temperature.

Abstract: A treatment for prevention of stress corrosion cracking (SCC) and a treated component are disclosed. A surface of a relatively high tensile strength component is heated to a temperature at which at least one of tempering or annealing occurs. The surface is then cooled in a controlled manner so as to maintain a reduced tensile strength at the surface that minimizes SCC while keeping a relatively high tensile strength in the remainder of the component.

Abstract: Embodiments of the invention relate generally to welding methods and, more particularly, to methods for welding in a horizontal position and a joint structure suitable for such methods. In one embodiment, the invention provides a method of forming a welded joint between two components, the method comprising: aligning a first and second component to form a joint therebetween, the joint comprising: a protrusion of the first component, and a recess of the second component, wherein the protrusion and recess have complimentary shapes; orienting the first and second components such that a major axis of each is oriented vertically; and welding the first and second components at a substantially horizontally-oriented root opening, the substantially horizontally-oriented root opening positioned along the joint.

Abstract: A method of making a multiple alloy, multi-section welded turbine rotor includes providing a forged multiple alloy rotor section having an integral microstructure, the rotor section comprising a first alloy having a first alloy composition and second alloy having a second alloy composition, a first weld face comprising the first alloy on a first end and an a second weld face comprising the second alloy on an opposed second end. The method also includes providing a first rotor section comprising the first alloy composition and a second rotor section comprising the second alloy composition. The method also includes welding the first rotor section to the first weld face and welding the second rotor section to the second weld face.