Abstract: A method of providing boiler tubes with a variably ribbed interior surface. A suitably dimensioned spindle with a channel having a desired pattern on the exterior surface of the spindle is wrapped by a wire-like member in the channel so as to form thereon a reverse image of the desired, patterned tube ribbing. A brazing metal paste is applied on the exterior surface of the wire-like member and the spindle is inserted into a tube to be ribbed. The wire-like member is released from the spindle to allow the wire-like member to conform to the inner surface of the tube, and the tube is heated to the melting temperature of the brazing metal paste so that the wire-like member bonds to the inner surface of the tube, and the metal tube is then cooled.

Abstract: A method of providing boiler tubes with a variably ribbed interior surface. A suitably dimensioned spindle with a channel having a desired pattern on the exterior surface of the spindle is wrapped by a wire-like member in the channel so as to form thereon a reverse image of the desired, patterned tube ribbing. A brazing metal paste is applied on the exterior surface of the wire-like member and the spindle is inserted into a tube to be ribbed. The wire-like member is released from the spindle to allow the wire-like member to conform to the inner surface of the tube, and the tube is heated to the melting temperature of the brazing metal paste so that the wire-like member bonds to the inner surface of the tube, and the metal tube is then cooled.

Abstract: A method for producing chromium carbide coatings on steel provides a steel component having a surface which is carburized to contain at least about 0.40% by weight carbon and is followed by chromizing the surface to form a chromium carbide coating on the surface.

Abstract: An improved process for chromizing and chrome-siliconizing 400-series stainless steel components, and in particular, 430 stainless steel components, such as boiler panel studs. The process includes the addition of between 0.12%-0.25% by weight of calcium fluoride salt to the conventional 4% by weight of ammonium chloride activator salt to the coating composition used in known diffusion coating processes. In a more preferred embodiment, small amounts of silicon powder, such as between about 0.12%-0.25% by weight, are added to the two salts and the diffusion coating material. A coating composition is provided as well.

Abstract: An improved method and apparatus for producing flexible fibers (30) of superconducting material includes a crucible (12) for containing a charge of the superconducting material. The material is melted in the crucible (12) and falls in a stream (18) through a bottom hole (16) in the crucible (12). The stream (18) falls through a protecting collar (22) which maintains the stream (18) at high temperatures. The stream (18) is then supplied through a downwardly directed nozzle (26) where it is subjected to a high velocity of a heated gas (36′) which breaks the melted superconducting material into ligaments which solidify into the flexible fibers (30). The fibers (30) are collected by directing them against a collection filter (32).

Abstract: An improved process for chromizing commercial quantities of small, industrial, ferrous-based parts, such as but not limited to threaded connectors, pins, bolts, nuts, washers, fasteners, fittings, couplings, studs, etc., uses a retort filled with layers of parts coated with a chromium-containing slurry. The plurality of parts are arranged in layers on sheets of refractory felt paper and are heat treated simultaneously for causing the chromizing reaction between the slurry and the ferrous-based parts.

Abstract: An improved method and apparatus for producing flexible fibers (30) of superconducting material includes a crucible (12) for containing a charge of the superconducting material. The material is melted in the crucible (12) and falls in a stream (18) through a bottom hole (16) in the crucible (12). The stream (18) falls through a protecting collar (22) which maintains the stream (18) at high temperatures. The stream (18) is then supplied through a downwardly directed nozzle (26) where it is subjected to a high velocity of a heated gas (36') which breaks the melted superconducting material into ligaments which solidify into the flexible fibers (30). The fibers (30) are collected by directing them against a collection filter (32).

Abstract: An elongated heat exchanger tube has an internally located stiffener assembly which prevents the deflection of the tube wall due to pressure differentials between the tube internal and external surfaces while allowing the flow of fluid between the areas on opposite sides of the stiffener inside of the tube. The heat exchanger tube can have an elliptical, oval or flat cross-section. The internal stiffener can have a variety of cross-sectional configurations having uniform or non-uniform shapes.