Abstract: A method of manufacturing a weld-free apparatus for use in the connection of dissimilar metals includes the steps of providing a mold designed to replicate a reverse of the apparatus, introducing a low alloy, ferritic steel composition atomized powder into a first portion of the mold, introducing a series of atomized powders incrementally into a second portion of the mold to form a transition region between the ferritic steel composition and an austenitic stainless steel composition, and introducing an austenitic stainless steel composition atomized powder into a third portion of the mold. The method further includes the step of consolidating and melting the atomized powders in a high temperature, high pressure inert gas atmosphere to form the apparatus.

Abstract: A method of manufacturing integral head and tube replacement sections includes the steps of providing a reverse mold of a head and tube replacement section, providing an atomized steel powder, and filling the reverse mold with the atomized steel powder. The method further includes the step of inserting the mold into a hot isostatic processing (HIP) furnace to consolidate and sinter the powder into the shape of the head and tube replacement section.

Abstract: In one embodiment, the present invention provides a method for welding together two metal pieces, comprising buttering a surface of a first metal piece with a first nickel-based filler metal at a thickness sufficient to isolate a heat-affected zone in the first metal piece from subsequent welding; heat-treating at least the heat-affected zone in the first metal piece; buttering a surface of a second metal piece with a second nickel-based filler metal having the same composition as the first nickel-based filler metal and at a thickness sufficient to isolate a heat-affected zone in the second metal piece from subsequent welding; heat-treating at least the heat-affected zone in the second metal piece; and welding the heat-treated first buttered surface to the heat-treated second buttered surface with a third nickel-based filler metal having the same composition as the first and second nickel-based filler metals.

Abstract: Accordingly, the present invention provides a weld filler composition for joining different alloy steel pieces with substantially different chromium content, such as joining low alloy ferritic steel to high alloy ferritic steel, low alloy ferritic steel to austenitic stainless steel, or high alloy ferritic steel to austenitic stainless steel, and a method using the same. In one embodiment, the present invention provides a composition for a weld filler comprising nickel, iron, and chromium, which collectively comprise at least 50% by weight of the weld filler; niobium, carbon, manganese, molybdenum, and silicon, which collectively comprise no more than 50% by weight of the weld filler, and a niobium to carbon ratio of approximately 20 or less.

Abstract: In one embodiment, the present invention provides a method for welding together two metal pieces, comprising buttering a surface of a first metal piece with a first nickel-based filler metal at a thickness sufficient to isolate a heat-affected zone in the first metal piece from subsequent welding; heat-treating at least the heat-affected zone in the first metal piece; buttering a surface of a second metal piece with a second nickel-based filler metal having the same composition as the first nickel-based filler metal and at a thickness sufficient to isolate a heat-affected zone in the second metal piece from subsequent welding; heat-treating at least the heat-affected zone in the second metal piece; and welding the heat-treated first buttered surface to the heat-treated second buttered surface with a third nickel-based filler metal having the same composition as the first and second nickel-based filler metals.

Abstract: In one embodiment, the present invention provides a method for welding together two metal pieces, comprising buttering a surface of a first metal piece with a first nickel-based filler metal at a thickness sufficient to isolate a heat-affected zone in the first metal piece from subsequent welding; heat-treating at least the heat-affected zone in the first metal piece; buttering a surface of a second metal piece with a second nickel-based filler metal having the same composition as the first nickel-based filler metal and at a thickness sufficient to isolate a heat-affected zone in the second metal piece from subsequent welding; heat-treating at least the heat-affected zone in the second metal piece; and welding the heat-treated first buttered surface to the heat-treated second buttered surface with a third nickel-based filler metal having the same composition as the first and second nickel-based filler metals.

Abstract: A method, an apparatus (150), and a prefabricated replacement tube (108) are provided for repairing a defect (112) in a tube (102), such as in a waterwall (100). In the method, a replacement tube (108) is prefabricated having a wall (116), a central opening (114) extending through a portion thereof, and a predetermined length. A length of the tube (102), including the defect (112), equal to the predetermined length is removed. The replacement tube (108) is positioned between stubs (126, 128) of the tube (102), and a rotatable torch (152) of an automated welding apparatus (150) inserted through the opening (114) to align with a joint between an end (118, 120) of the replacement tube and a stub (126, 128). The torch (152) is rotated to join it to the stub (126, 128) along the entire joint. The torch (152) is then removed, turned 180 degrees, and reinserted to weld the remaining joint.

Abstract: A method, a apparatus (150) and a prefabricated replacement tube (108) are provided for repairing a defect (112) in a tube (102), such as in a waterwall (100). In the method, a replacement tube (108) is prefabricated having a wall (116), a central opening (114) extending through a portion thereof and a predetermined length. A length of the tube (102), including the defect (112), equal to the predetermined length is removed. The replacement tube (108) is positioned between stubs (126, 128) of the tube (102), and a rotatable torch (152) of an automated welding apparatus (150) inserted through the opening (114) to align with a joint between an end (118, 112) of the replacement tube and a stub (126, 128). The torch (152) is rotated to join it to the stub (126, 128) along the entire joint. The torch (152) is then removed, turned 180 degrees, and reinserted to weld the remaining joint.