Abstract: A rotor disc configured to reduce the likelihood of fractures developing in spindle bolts in gas turbine engines is disclosed. The spindle bolts extend axially through the rotor disc to retain the rotor assembly in place in the gas turbine engine. The rotor disc may be formed from a rotor disc body having a plurality of circumferentially positioned spindle bolt holes sized to house a spindle bolts within each spindle bolt hole. One or more relief channels, which also may be referred to as scallops, may extend radially outward from one of the spindle bolt holes. The relief channels may foster removal of condensation and debris from the space between the spindle bolt and the surface forming the spindle bolt hole and may be configured to discourage the ingress of air through the relief channel and into space between the spindle bolt and the surface forming the spindle bolt hole.

Abstract: A removed damaged portion of a fully consolidated turbine engine component is replaced with a powder coupon that includes powder particles that are at most partially sintered or are bonded together with a binder. A bonding agent is applied to the component and/or the powder coupon. The powder coupon is then positioned over the component and heat is applied to fully sinter the powder particles, thus causing the powder coupon to shrink onto the component. The heat also activates the bonding agent to bond the shrunken powder coupon to the component, but the heat does not sinter the material forming the fully consolidated component.

Abstract: A spindle bolt structure is provided in a gas turbine engine, and includes a pilot region located within a bolt hole extending through a seal disk. The pilot region includes a circumferential pilot ridge located adjacent to a downstream axial face of the seal disk and a circumferential trough portion located between a bolt shoulder and the pilot ridge. The trough portion defines a trough diameter that is less than a diameter of the bolt shoulder and less than a diameter of the pilot ridge. The bolt shoulder and pilot ridge are formed with an applied compressive residual stress and are positioned for engagement with the seal disk.

Abstract: Ultrasonic bolt inspection apparatus and methods facilitate in situ as well as bench non-destructive evaluation (NDE) inspection of fastening bolt distal ends and their mating nuts. The apparatus is coupled to an exposed end of a fastener bolt head, its exposed thread tip or to a mating nut. The apparatus retains a phased array ultrasonic probe that generates inspection scan data and a rotational position encoder that generates rotational position data. The probe is coupled to an ultrasonic inspection system analyzer, which converts scan data into inspection data that characterizes possible defects in the inspected bolt. A system controller is coupled to the analyzer and the rotational position encoder, correlating rotation position data and inspection data, in order to identify location and characteristics of possible defects in the inspected bolt end.

Abstract: Ni base superalloys containing relatively large amounts of Al and/or Ti are known to be difficult to weld satisfactorily. As the Al and Ti content of the superalloy is increased to improve the strength, the weldability of the component is drastically reduced. It is concluded herein that reducing the ?? phase improves weldability. A stepwise, controlled heating and cooling process is described to be used in cooperation with a welding process to reduce the ?? present and thereby improve weldability.

Abstract: A spindle bolt structure is provided in a gas turbine engine, and includes a pilot region located within a bolt hole extending through a seal disk. The pilot region includes a circumferential pilot ridge located adjacent to a downstream axial face of the seal disk and a circumferential trough portion located between a bolt shoulder and the pilot ridge. The trough portion defines a trough diameter that is less than a diameter of the bolt shoulder and less than a diameter of the pilot ridge. The bolt shoulder and pilot ridge are formed with an applied compressive residual stress and are positioned for engagement with the seal disk.

Abstract: A fatigue resistant turbine through bolt formed from a base material covered by a first surface modification and a second surface modification is disclosed. The first surface modification may be in contact with the base material and, in at least one embodiment, may be a low plasticity burnished layer that increases the residual compressive stresses on an outer surface of the turbine through bolt. The second surface modification may cover the first surface modification and, in at least one embodiment, may be a spinel oxide layer on the low plasticity burnished layer. The second surface modification may be positioned on the first surface modification or on the bare turbine through bolt contact surface without low plastiocity burnishing on the shaft of the turbine through bolt. The first and second surface modifications reduce the likelihood of fretting fatigue failures.

Abstract: Ni base superalloys containing relatively large amounts of Al and/or Ti are known to be difficult to weld satisfactorily. As the Al and Ti content of the superalloy is increased to improve the strength, the weldability of the component is drastically reduced. It is concluded herein that reducing the ?? phase improves weldability. A stepwise, controlled heating and cooling process is described to be used in cooperation with a welding process to reduce the ?? present and thereby improve weldability.

Abstract: A rotor disc configured to reduce the likelihood of fractures developing in spindle bolts in gas turbine engines is disclosed. The spindle bolts extend axially through the rotor disc to retain the rotor assembly in place in the gas turbine engine. The rotor disc may be formed from a rotor disc body having a plurality of circumferentially positioned spindle bolt holes sized to house a spindle bolts within each spindle bolt hole. One or more relief channels, which also may be referred to as scallops, may extend radially outward from one of the spindle bolt holes. The relief channels may foster removal of condensation and debris from the space between the spindle bolt and the surface forming the spindle bolt hole and may be configured to discourage the ingress of air through the relief channel and into space between the spindle bolt and the surface forming the spindle bolt hole.

Abstract: Ultrasonic bolt inspection apparatus and methods facilitate in situ as well as bench non-destructive evaluation (NDE) inspection of fastening bolt distal ends and their mating nuts. The apparatus is coupled to an exposed end of a fastener bolt head, its exposed thread tip or to a mating nut. The apparatus retains a phased array ultrasonic probe that generates inspection scan data and a rotational position encoder that generates rotational position data. The probe is coupled to an ultrasonic inspection system analyzer, which converts scan data into inspection data that characterizes possible defects in the inspected bolt. A system controller is coupled to the analyzer and the rotational position encoder, correlating rotation position data and inspection data, in order to identify location and characteristics of possible defects in the inspected bolt end.

Abstract: A superalloy component, such as gas turbine blade or vane, is structurally welded by placing the component in an isolation chamber. Inert gas is introduced into the chamber. The substrate is welded in the chamber, creating a weld zone. Pressure is applied directly on the weld zone that is greater than atmospheric pressure. Application of such pressure increases the weld zone ductility and reduces likelihood of solidification cracking and strain age cracking, compared to weld zones formed at atmospheric pressure. In some embodiments an isostatic pressure chamber is used to apply isostatic pressure on the weld zone. In other embodiments the welding is performed by laser welding or cladding, TIG welding electron beam welding or autogenous welding.

Abstract: A removed damaged portion of a fully consolidated turbine engine component is replaced with a powder coupon that includes powder particles that are at most partially sintered or are bonded together with a binder. A bonding agent is applied to the component and/or the powder coupon. The powder coupon is then positioned over the component and heat is applied to fully sinter the powder particles, thus causing the powder coupon to shrink onto the component. The heat also activates the bonding agent to bond the shrunken powder coupon to the component, but the heat does not sinter the material forming the fully consolidated component.

Abstract: A composition and method for cleaning turbine engine components (10) during servicing. An embodiment of the invention includes a colloidal mixture or slurry (22) of nanoparticles. The slurry may be nontoxic and provide optimal cleaning of tiny surface-exposed crevices (18) of braze joints and components. When a colloidal mixture is in a polar solvent, the pH of the slurry is maintained at about 5 to 9 and at the isoelectric point of the nanoparticles to minimize or prevent agglomeration. When a colloidal mixture is in a nonpolar solvent, the pH of the slurry is maintained at about 5 to 9 and at the isoelectric point of the nanoparticles to minimize or prevent agglomeration by use of surfactant additives.

Abstract: A composition and method for cleaning turbine engine components (10) during servicing. An embodiment of the invention includes a colloidal mixture or slurry (22) of nanoparticles. The slurry may be nontoxic and provide optimal cleaning of tiny surface-exposed crevices (18) of braze joints and components. When a colloidal mixture is in a polar solvent, the pH of the slurry is maintained at about 5 to 9 and at the isoelectric point of the nanoparticles to minimize or prevent agglomeration. When a colloidal mixture is in a nonpolar solvent, the pH of the slurry is maintained at about 5 to 9 and at the isoelectric point of the nanoparticles to minimize or prevent agglomeration by use of surfactant additives.