Abstract: The refurbishing process permits an overlay to be formed on a casting to repair cracks, distortions and the like as well as to build up undersized sections. During refurbishing, a plasma arc is established under an electric current of less than 30 amps to form a shallow pool of molten metal on a casting. Powdered metal is delivered slightly above the molten pool and, subsequently, the melted powder and molten pool solidify to an overlay having a high integrity, cast structure which is metallurgically bonded to the casting with minimal dilution.

Abstract: A cutting tool is provided with a fabricated cutting edge which is applied using a low heat plasma transferred arc and powdered metal. The heat affected zone between the applied edge and the substrate is maintained at a minimum with low dilution and penetration of the applied material relative to the substrate.

Abstract: The shrouded turbine blade is provided with a wear resistant surface on the seals as well as along the abutment faces including the notched edges. The wear surfaces are characterized in being metallurgically bonded to the base material of the shroud without significant dilution by the base material. This is accomplished by using transparent plasma arc welding at a low amperage and a low temperature. The wear resistant surface can be of a material different from the base material of the shroud proper.

Abstract: The worn tip of a turbine blade is restored by applying a metallurgically bonded wear resistant surface at the tip. The wear resistant surface is applied using a transferred plasma arc and powdered metal particles.

Abstract: The welding method may be used to lay down weld beads on metallic substrates with a narrow width of 0.125 inch and less. The process employs a plasma transferred arc and pulses the current delivered to the arc such that a wave form having at least a main amplitude and a lower auxiliary amplitude is provided. The powdered metal which is delivered is laid down in a series of overlapping weld deposits which solidify very rapidly and produce a fine grain structure.

Abstract: The welding method is used to lay down weld beads on metallic substrates with a thin section, e.g., of down to 0.030 inch. The process employs a plasma transferred arc which is generated at low current, e.g., between 0.5 amps and 60 amps, and with a very high switching frequency, e.g., 15 KHz at the power supply. A low amount of heat is generated so that the thin section is not burned through. The surfacing powder is delivered into the arc and becomes metallurgically bonded to the substrate.

Abstract: The welding method may be used to lay down weld beads on metallic substrates with a narrow width of 0.125 inch and less. The process employs a plasma transferred arc and pulses the current delivered to the arc such that a wave form having at least a main amplitude and a lower auxiliary amplitude is provided. The powdered metal which is delivered is laid down in a series of overlapping weld deposits which solidify very rapidly and produce a fine grain structure.

Abstract: The filter assembly is constructed of outer sleeves of wire screen, a mass of shattered metal particles within the sleeves and at least one tubular filter element within the shattered metal particles. The mass of shattered metal particles serves to remove micro-gels from the polymeric material flowing through the filter assembly while the inner filter element serves to remove particulate matter.

Abstract: There is disclosed a process for forming a hardfacing surface including particulate refractory metal carbide by directing a plasma transferred arc against a wear surface of an element and passing a powder comprised of refractory metal carbide particles admixed in a suitable hard metal matrix through the plasma arc to thereby form on the wear surface of the element a hardfacing surface including particulate refractory metal carbide of a thickness of from 0.04 to 0.25 inches.