An assembly and method for repairing sheathing on a tension member of a post-tensioning tendon may include an outer tube having first and second end portions, a tubular long seal positioned inside the outer tube, the tubular long seal being shorter than the outer tube, first and second seals positioned in the first and second end portions of the outer tube, respectively, and first and second nuts retaining the first and second seals in the first and second end portions of the outer tube, respectively. The assembly may define a longitudinal passage adapted to receive the tension member and the presence of the assembly on the tension member seals the portion of the tension member that is within the assembly. An inner tube may be positioned between the outer tube and the tubular long seal and may radially compress the tubular long seal.

A method of repairing an active leak in embodiments of the present invention may include one or more of the following steps: (a) identifying the active leak on a pipe structure, tank or pressure vessel, (b) setting cold spray system settings to repair the pipe structure, (c) administering pressurized gas and metal powder to an active pipe leak, (d) identifying any potential hazards surrounding the active pipe leak, (e) eliminating and/or reducing the potential hazards surround the active pipe leak, (f) inserting a wedge within an active leak pipe hole, (g) ceasing administration of pressurized gas and metal powder to the active pipe leak when it appears sealed, (h) verifying the active pipe leak is sealed, and (i) re-administering the pressurized gas and the metal powder to the active leak is the active leak is not fully sealed.

A repair welding method according to at least one embodiment is for a member in which a first end and a second end of a parent material are connected by welding and includes: a step of removing a portion including at least a part of a first heat-affected zone of an existing welded portion of the member; and a step of performing repair welding after removing the portion. In a cross-section including the parent material and the existing welded portion, all intersection portions between the first heat-affected zone of the existing welded portion and a second heat-affected zone due to the repair welding have an intersection angle between the first heat-affected zone and the second heat-affected zone of 70° to 110°.

A repair welding method according to at least one embodiment is for a member in which a first end and a second end of a parent material are connected by welding and includes: a step of removing a portion including at least a part of a first heat-affected zone of an existing welded portion of the member; and a step of performing repair welding after removing the portion. In a cross-section including the parent material and the existing welded portion, all intersection portions between the first heat-affected zone of the existing welded portion and a second heat-affected zone due to the repair welding have an intersection angle between the first heat-affected zone and the second heat-affected zone of 70° to 110°.

Example aspects of a disk stack repair insert, a repaired disk stack, and a method for repairing a disk stack are disclosed. The disk stack repair insert can comprise a first replacement disk segment defining a first groove pattern comprising first grooves; and a second replacement disk segment defining a second groove pattern comprising second grooves, the first replacement disk segment coupled to the second replacement disk segment, wherein the first groove pattern and the second groove pattern define a fluid passageway therebetween.

Example aspects of a disk stack repair insert, a repaired disk stack, and a method for repairing a disk stack are disclosed. The disk stack repair insert can comprise a first replacement disk segment defining a first groove pattern comprising first grooves; and a second replacement disk segment defining a second groove pattern comprising second grooves, the first replacement disk segment coupled to the second replacement disk segment, wherein the first groove pattern and the second groove pattern define a fluid passageway therebetween.

The present invention is directed to in situ methods for maintaining turbine assemblies. One such method includes: disposing a maintenance apparatus on the rotor; positioning the maintenance apparatus proximate to the damaged region by rotating the rotor; and repairing the damaged region by operating a repair tool disposed on the apparatus. Another method includes: disposing a maintenance apparatus on the stator; positioning the damaged region proximate to the maintenance apparatus by rotating the rotor; and repairing the damaged region by operating a repair tool disposed on the apparatus.

A micro-nano composite powder dedicated for laser repair of tiny crack on stainless steel surface, includes 3 wt %-7 wt % of nano-WC, 0.5 wt %-2 wt % of nano-Al.sub.2O.sub.3, 0.2 wt %-0.8 wt % of micro-V powder and the balance of micro stainless steel powder. The stainless steel powder includes 0.08 wt % of C, 0.5 wt % of Si, 1.46 wt % of Mn, 0.03 wt % of P, 0.005 wt % of S, 19 wt % of Cr, 9.5 wt % of Ni, 0.5 wt % of Mo and the balance of Fe. The micro and nano powders are mixed through ball milling and mixed with anhydrous ethanol. The composite powder is suitable for laser repair of tiny crack on the surface of stainless steel part with high toughness requirement. After laser repair, the composite powder can be fused with the substrate, the repaired layer and the substrate are metallurgically bonded at the interface, the repaired layer contains fine grains, and therefore the compatibility and fracture property of the repaired layer are improved.

A micro-nano composite powder dedicated for laser repair of tiny crack on stainless steel surface, includes 3 wt %-7 wt % of nano-WC, 0.5 wt %-2 wt % of nano-Al.sub.2O.sub.3, 0.2 wt %-0.8 wt % of micro-V powder and the balance of micro stainless steel powder. The stainless steel powder includes 0.08 wt % of C, 0.5 wt % of Si, 1.46 wt % of Mn, 0.03 wt % of P, 0.005 wt % of S, 19 wt % of Cr, 9.5 wt % of Ni, 0.5 wt % of Mo and the balance of Fe. The micro and nano powders are mixed through ball milling and mixed with anhydrous ethanol. The composite powder is suitable for laser repair of tiny crack on the surface of stainless steel part with high toughness requirement. After laser repair, the composite powder can be fused with the substrate, the repaired layer and the substrate are metallurgically bonded at the interface, the repaired layer contains fine grains, and therefore the compatibility and fracture property of the repaired layer are improved.

A method for a laser surface treatment of furnace furniture of a heating furnace, which furnace furniture is used for the support of metal products in the heating furnace, the method including the steps of: setting a laser device to generate a laser beam of a pre-defined power, guiding the laser beam over the surface of the furnace furniture with a pre-defined velocity, such that the surface of the furnace furniture is heated locally to above its melting temperature.