Systems and methods for thermally modifying an ice-to-object interface. One system includes a power supply configured to generate a magnitude of power. The magnitude of the power is sufficient to melt an interfacial layer of ice at the interface; typically the interfacial layer has a thickness in a range one micron to one millimeter. A controller may be used to limit the duration in which power supply generates the magnitude of the power, to limit unneeded heat energy dissipation into the environment. Modulating the pulsed heating energy to the interface modifies a coefficient of friction between the object and the ice.

Systems and methods for modifying an ice-to-object interface

A process is provided for welding a nickel or cobalt based superalloy article to minimize cracking by preheating the entire weld area to a maximum ductility temperature range, maintaining such temperature during welding and solidification of the weld, raising the temperature for stress relief of the superalloy, then cooling at a rate effective to minimize gamma prime precipitation.

Welding superalloy articles

A method is disclosed of repairing cracks (5) on a surface (6) of a component (1) such as gas turbine components. The method comprises the steps of repairing the cracks (5) of the component by brazing, detecting by any means remaining cracks (5) on the surface (6) or below the surface (6), which were not properly filled with braze material (7) during the repair brazing operation and repairing the crack zones with a focussed low-heat input welding method using an appropriate weld filler material (10).

Crack repair method

A solid-solution strengthened superalloy weld composition, includes: about 0 to about 10 wt % Co; about 18 to about 22 wt % Cr; about 0.2 to about 0.7 wt % Al; about 15 to about 28 wt % of the sum of refractory elements; up to about 0.09 wt % C; up to about 0.06 wt % Zr; up to about 0.015 wt % B; about 0.4 to about 1.2 wt % Mn; about 0.2 to about 0.45 wt % Si; and balance Ni.

Superalloy weld composition and repaired turbine engine component

Systems and methods for pulse electrothermal and heat-storage ice detachment. A pulse electrothermal ice detachment apparatus includes one or more coolant tubes, and optionally, fins in thermal contact with the coolant tubes. The tubes and/or fins form a resistive heater. Apparatus applies electrical power to the resistive heater, generating heat to detach ice from the tubes and/or the fins. A freezer unit forms a heat-storage icemaking system having a compressor and a condenser for dissipating waste heat, and coolant that circulates through the compressor, the condenser and a coolant tube. The coolant tube is in thermal contact with an evaporator plate. A tank, after the compressor and before the condenser, transfers heat from the coolant to a heating liquid. The heating liquid periodically flows through a heating tube in thermal contact with the evaporator plate, detaching ice from the evaporator plate.

Pulse electrothermal and heat-storage ice detachment apparatus and methods

An article made of a nickel-base superalloy having a nil-ductility range from the solidus temperature of the alloy to about 600° F. below the solidus temperature is welded, as for example in the weld repair of surface cracks, by removing foreign matter from the area to be welded, first stress relieving the article, adjusting the temperature of the article to a welding temperature of from about 1800° F. to about 2100° F., welding a preselected area in an inert atmosphere at the welding temperature, and second stress relieving the article. Welding is preferably accomplished by striking an arc in the preselected area so as to locally melt the alloy in the preselected area, providing a filler metal having the same composition as the nickel-based superalloy of the article, and feeding the filler metal into the arc so that the filler metal is melted and fused with the article to form a weldment upon solidification.

/pdf/welding-of-nickel-base-superalloys-having-a-nil-ductility-2vklt3ou44.pdf

Welding of nickel-base superalloys having a nil-ductility range

A heating apparatus (10) and method for pre-weld heat treating, welding and post-weld heat treating a superalloy article in a single enclosure (12) while avoiding oxidation of the article. The enclosure (12) is preferably equipped with a one-way valve (32) that permits the escape of gases, but otherwise seals the enclosure (12) to prevent the ingress of air during welding and heat treatment as a result of thermal gradients induced when the article is inductively heated. To provide access to the article and a device (20) used to weld the article, the enclosure (12) is equipped with gloves (30) by which the welding device (20) and the article can be manipulated while a nonreactive atmosphere is fully maintained within the enclosure (12) and the article is inductively heating.

Heating apparatus for a welding operation and method therefor

A directionally solidified nickel-base superalloy article has a defect therein extending parallel to the solidification direction. The article is repaired by removing any foreign matter present in the defect, and then heating the article to a repair temperature of from about 60 to about 98 percent of the solidus temperature of the base material in a chamber containing a protective gas that inhibits oxidation of the base material. The defect is filled with a filler metal while maintaining the article at the repair temperature. The filling is accomplished by providing a source of the filler metal of substantially the same composition as the base material of the directionally solidified article, and melting the filler metal into the defect progressively while moving the source of the filler metal relative to the article in a direction parallel to the solidification direction. Optionally, additional artificial heat extraction is accomplished in a heat-flow direction that is within about 45 degrees of the solidification direction, as the filler metal solidifies within the defect. The article may thereafter be heat treated.

/pdf/directionally-solidified-article-with-weld-repair-59u713sjqa.pdf

Directionally solidified article with weld repair

A directionally solidified nickel-based superalloy article (40) has a defect (58) therein extending parallel to the solidification direction (54). The article (40) is repaired by removing any foreign matter present in the defect (58), and then heating the article (40) to a repair temperature of from about 60 to about 98 percent of the solidus temperature of the base material in a chamber containing a protective gas that inhibits oxidation of the base material. The defect (58) is filled with a filler metal while maintaining the article (40) at the repair temperature. The filling is accomplished by providing a source of the filler metal of substantially the same composition as the base material of the directionally solidified article (40), and melting the filler metal into the defect (58) progressively while moving the source of the filler metal relative to the article (40) in a direction parallel to the solidification direction (54). Optionally, additional artificial heat extraction is accomplished in a heat-flow direction that is within about 45 degrees of the solidification direction (54), as the filler metal solidifies within the defect (58). The article (40) may thereafter be heat treated.

/pdf/weld-repair-of-directionally-solidified-articles-h1d6ixbz8t.pdf

Weld repair of directionally solidified articles

An article made of a gamma titanium aluminide alloy is welded, as for example in the weld repair of surface cracks, by removing foreign matter from the area to be welded, first stress relieving the article, cooling the entire article to a welding temperature of from about 1000° F. to about 1400° F., welding a preselected region in an inert atmosphere at the welding temperature, and second stress relieving the article. Welding is preferably accomplished by striking an arc in the preselected region so as to locally melt the alloy in the preselected region, providing a filler metal having the same composition as the gamma titanium aluminide alloy of the article, and feeding the filler metal into the arc so that the filler metal is melted and fused with the article to form a weldment upon solidification.

/pdf/welding-of-gamma-titanium-aluminide-alloys-2r8k0d8lno.pdf

John H. Snyder

Papers

Welding of nickel-base superalloys having a nil-ductility range

Heating apparatus for a welding operation and method therefor

Directionally solidified article with weld repair

Weld repair of directionally solidified articles

Welding of gamma titanium aluminide alloys